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2018-08-20clear alternative URIs for mirror:// between steps (CVE-2018-0501)David Kalnischkies
APT in 1.6 saw me rewriting the mirror:// transport method, which works comparable to the decommissioned httpredir.d.o "just" that apt requests a mirror list and performs all the redirections internally with all the bells like parallel download and automatic fallback (more details in the apt-transport-mirror manpage included in the 1.6 release). The automatic fallback is the problem here: The intend is that if a file fails to be downloaded (e.g. because the mirror is offline, broken, out-of-sync, …) instead of erroring out the next mirror in the list is contacted for a retry of the download. Internally the acquire process of an InRelease file (works with the Release/Release.gpg pair, too) happens in steps: 1) download file and 2) verify file, both handled as URL requests passed around. Due to an oversight the fallbacks for the first step are still active for the second step, so that the successful download from another mirror stands in for the failed verification… *facepalm* Note that the attacker can not judge by the request arriving for the InRelease file if the user is using the mirror method or not. If entire traffic is observed Eve might be able to observe the request for a mirror list, but that might or might not be telling if following requests for InRelease files will be based on that list or for another sources.list entry not using mirror (Users have also the option to have the mirror list locally (via e.g. mirror+file://) instead of on a remote host). If the user isn't using mirror:// for this InRelease file apt will fail very visibly as intended. (The mirror list needs to include at least two mirrors and to work reliably the attacker needs to be able to MITM all mirrors in the list. For remotely accessed mirror lists this is no limitation as the attacker is in full control of the file in that case) Fixed by clearing the alternatives after a step completes (and moving a pimpl class further to the top to make that valid compilable code). mirror:// is at the moment the only method using this code infrastructure (for all others this set is already empty) and the only method-independent user so far is the download of deb files, but those are downloaded and verified in a single step; so there shouldn't be much opportunity for regression here even through a central code area is changed. Upgrade instructions: Given all apt-based frontends are affected, even additional restrictions like signed-by are bypassed and the attack in progress is hardly visible in the progress reporting of an update operation (the InRelease file is marked "Ign", but no fallback to "Release/Release.gpg" is happening) and leaves no trace (expect files downloaded from the attackers repository of course) the best course of action might be to change the sources.list to not use the mirror family of transports ({tor+,…}mirror{,+{http{,s},file,…}}) until a fixed version of the src:apt packages are installed. Regression-Of: 355e1aceac1dd05c4c7daf3420b09bd860fd169d, 57fa854e4cdb060e87ca265abd5a83364f9fa681 LP: #1787752
2018-08-08Set DPKG_FRONTEND_LOCKED as needed when doing selection changesJulian Andres Klode
We forgot to set the variable for the selection changes. Let's set it for that and some other dpkg calls. Regression-Of: c2c8b4787b0882234ba2772ec7513afbf97b563a
2018-08-07Add support for dpkg frontend lockJulian Andres Klode
The dpkg frontend lock is a lock dpkg tries to acquire except if the frontend already acquires it. This fixes a race condition in the install command where the dpkg lock is not held for a short period of time between different dpkg invocations. For this reason we also define an environment variable DPKG_FRONTEND_LOCKED for dpkg invocations so dpkg knows not to try to acquire the frontend lock because it's held by a parent process. We can set DPKG_FRONTEND_LOCKED only if the frontend lock really is held; that is, if our lock count is greater than 0 - otherwise an apt client not using the LockInner family of functions would run dpkg without the frontend lock set, but with DPKG_FRONTEND_LOCKED set. Such a process has a weaker guarantee: Because dpkg would not lock the frontend lock either, the process is prone to the existing races, and, more importantly, so is a new style process. Closes: #869546 [fixups: fix error messages, add public IsLocked() method, and make {Un,}LockInner return an error on !debSystem]
2018-07-06Use cheaper entropy source for randomizing items to fetchJulian Andres Klode
The random_device fails if not enough entropy is available. We do not need high-quality entropy here, though, so let's switch to a seed based on the current time in nanoseconds, XORed with the PID.
2018-06-13Fix lock counting in debSystemJulian Andres Klode
debSystem uses a reference counted lock, so you can acquire it multiple times in your applications, possibly nested. Nesting locks causes a fd leak, though, as we only increment the lock count when we already have locked twice, rather than once, and hence when we call lock the second time, instead of increasing the lock count, we open another lock fd. This fixes the code to check if we have locked at all (> 0). There is no practical problem here aside from the fd leak, as closing the new fd releases the lock on the old one due to the weird semantics of fcntl locks.
2018-05-28Use a steady clock source for progress reportingDavid Kalnischkies
Clock changes while apt is running can result in strange reports confusing (and amusing) users. Sadly, to keep the ABI for now the code is a bit more ugly than it would need to be.
2018-05-28Don't show acquire warning for "hidden" componentsDavid Kalnischkies
Commit d7c92411dc1f4c6be098d1425f9c1c075e0c2154 introduced a warning for non-existent files from components not mentioned in Components to hint users at a mispelling or the disappearance of a component. The debian-installer subcomponent isn't actively advertised in the Release file through, so if apt ends up in acquiring a file which doesn't exist for this component (like Translation files) apt would produce a warning: W: Skipping acquire of configured file 'main/debian-installer/i18n/Translation-en' as repository 'http://deb.debian.org/debian buster InRelease' doesn't have the component 'main/debian-installer' (component misspelt in sources.list?) We prevent this in the future by checking if any file exists from this component which results in the warning to be produced still for the intended cases and silence it on the d-i case. This could potentially cause the warning not to be produced in cases it should be if some marginal file remains, but as this message is just a hint and the setup a bit pathological lets ignore it for now. There is also the possibility of having no file present as they would all be 0-length files and being a "hidden" component, but that would be easy to workaround from the repository side and isn't really actively used at the moment in the wild. Closes: #879591
2018-05-24Merge branch 'feature/morevolatilesupport' into 'master'Julian Andres Klode
more volatile: build-dep foo.deb/release & show foo.deb See merge request apt-team/apt!14
2018-05-24Merge branch 'feature/byhashviaalturl' into 'master'Julian Andres Klode
Don't force the same mirror for by-hash URIs See merge request apt-team/apt!15
2018-05-21Increase debug verbosity in `apt-get autoremove`Filipe Brandenburger
When running with Debug::pkgAutoRemove=yes, explain why certain packages are being marked, either because they're marked essential/important or because they match the blacklist from APT::NeverAutoRemove. This should help troubleshoot cases where autoremove is not proposing removal of packages expected to be up for removal. Tested manually with `apt-get autoremove -o Debug::pkgAutoRemove=yes`.
2018-05-11Don't force the same mirror for by-hash URIsDavid Kalnischkies
Downloading from the same mirror we got a Release file from makes sense for non-unique URIs as their content changes between mirror states, but if we ask for an index via by-hash we can be sure that we either get the file we wanted or a 404 for which we can perform a fallback for which allows us to pull indexes from different mirror in parallel.
2018-05-11Handle by-hash URI construction more centrallyDavid Kalnischkies
Individual items shouldn't concern themselves with these alternative locations, we can deal with this more efficiently within the infrastructure created for other alternative URIs now avoiding the need to implement this in each item.
2018-05-11Drop alternative URIs we got a hash-based fail fromDavid Kalnischkies
If we got a file but it produced a hash error, mismatched size or similar we shouldn't fallback to alternative URIs as they likely result in the same error. If we can we should instead use another mirror. We used to be a lot stricter by stopping all trys for this file if we got a non-404 (or a hash-based) failure, but that is too hard as we really want to try other mirrors (if we have them) in the hope that they have the expected and correct files.
2018-05-11Deprectate buggy/incorrect Rls/PkgFile::IsOk methodsDavid Kalnischkies
With the advent of compressed files and especially with in-memory post-processed files the simple assumptions made in IsOk are no longer true. Worse, they are at best duplicates of checks performed by the cache generation (and validation) earlier and isn't used in too many places. It is hence best to simply get right of these calls instead of trying to fix them.
2018-05-11Start pkg records for deb files with dpkg outputDavid Kalnischkies
It is easier to prepend our fields, but that results in confusion for things working on the so generated records as they don't start with the usual "Package" – that shouldn't be a problem in theory, but in practice e.g. "apt-cache show" shows these records directly to the user who will probably be more confused by it than tools.
2018-05-11don't try SRV requests based on IP addressesDavid Kalnischkies
IP addresses are by definition not a domain so in the best case the requests will just fail; we can do better than that on our own.
2018-05-07Remove obsolete RCS keywordsGuillem Jover
Prompted-by: Jakub Wilk <jwilk@debian.org>
2018-05-05Fix various typos reported by spellcheckersDavid Kalnischkies
Reported-By: codespell & spellintian Gbp-Dch: Ignore
2018-05-05Avoid implicitly promotion of float to doubleDavid Kalnischkies
Reported-By: gcc -Wdouble-promotion Gbp-Dch: Ignore
2018-04-20CMake: Fix builds without zstdJulian Andres Klode
Only use zstd defined variables if zstd was found.
2018-04-15Merge branch 'pu/zstd' into 'master'Julian Andres Klode
pu/zstd See merge request apt-team/apt!8
2018-04-13zstd: Implement support for multi-frame filesJulian Andres Klode
This implements support for multi frame files while keeping error checking for unexpected EOF working correctly. Files with multiple frames are generated by pzstd, for example.
2018-04-13Implement compression level handling for zstdJulian Andres Klode
This is a simplified variant of the code for xz, adapted to support multiple digit integers.
2018-04-07fix communication typo in https manpageDavid Kalnischkies
Reported-By: lintian spelling-error-in-manpage
2018-03-19Bump cache major version to allow different 1.5 and 1.6 updatesJulian Andres Klode
Shipping 1.6 with major 12 would not allow us to update 1.5.y in a different way than 1.6.y if we have to without resorting to minor version hacks. Let's just bump the major instead.
2018-03-15Use https for Ubuntu changelogsJulian Andres Klode
We just enabled https on changelogs.ubuntu.com, let's use it.
2018-03-12apt-pkg: Add support for zstdJulian Andres Klode
zstd is a compression algorithm developed by facebook. At level 19, it is about 6% worse in size than xz -6, but decompression is multiple times faster, saving about 40% install time, especially with eatmydata on cloud instances.
2018-02-19Merge branch 'pu/not-valid-before' into 'master'Julian Andres Klode
Check that Date of Release file is not in the future See merge request apt-team/apt!3
2018-02-19Check that Date of Release file is not in the futureJulian Andres Klode
By restricting the Date field to be in the past, an attacker cannot just create a repository from the future that would be accepted as a valid update for a repository. This check can be disabled by Acquire::Check-Date set to false. This will also disable Check-Valid-Until and any future date related checking, if any - the option means: "my computers date cannot be trusted." Modify the tests to allow repositories to be up to 10 hours in the future, so we can keep using hours there to simulate time changes.
2018-02-19ensure correct file permissions for auxfilesDavid Kalnischkies
The interesting takeaway here is perhaps that 'chmod +w' is effected by the umask – obvious in hindsight of course. The usual setup helps with hiding that applying that recursively on all directories (and files) isn't correct. Ensuring files will not be stored with the wrong permissions even if in strange umask contexts is trivial in comparison. Fixing the test also highlighted that it wasn't bulletproof as apt will automatically fix the permissions of the directories it works with, so for this test we actually need to introduce a shortcut in the code. Reported-By: Ubuntu autopkgtest CI
2018-02-19indexcopy: Copy uncompressed indices from cdrom againJulian Andres Klode
This was broken by a refactoring in 1adcf56bec7d2127d83aa423916639740fe8e586 which iterated over getCompressorExtensions() instead of the compressors and using their extension field. getCompressorExtensions() does not contain the empty extension for uncompressed files, though, and hence this was broken. LP: #1746807
2018-01-19allow the apt/lists/auxfiles/ directory to be missingDavid Kalnischkies
apt 1.6~alpha6 introduced aux requests to revamp the implementation of a-t-mirror. This already included the potential of running as non-root, but the detection wasn't complete resulting in errors or could produce spurious warnings along the way if the directory didn't exist yet. References: ef9677831f62a1554a888ebc7b162517d7881116 Closes: 887624
2018-01-17Introduce inrelease-path option for sources.listJulian Andres Klode
Allow specifying an alternative path to the InRelease file, so you can have multiple versions of a repository, for example. Enabling this option disables fallback to Release and Release.gpg, so setting it to InRelease can be used to ensure that only that will be tried. We add two test cases: One for checking that it works, and another for checking that the fallback does not happen. Closes: #886745
2018-01-05dpkg status parsing: check if name is valid before useDavid Kalnischkies
The summary line sounds a bit much: what we end up doing is just adding two more guards before using results which should always be valid™. That these values aren't valid is likely a bug in itself somewhere, but that is no reason for crashing.
2018-01-04simplify translating "lists directory missing" msgDavid Kalnischkies
The appended "partial" should not be translated, but some translations got this wrong and now that there is also "auxfiles" we can just fix that problem by hiding these untranslatables from the translators. Gbp-Dch: Ignore
2018-01-03require methods to request AuxRequest capability at startupDavid Kalnischkies
Allowing a method to request work from other methods is a powerful capability which could be misused or exploited, so to slightly limited the surface let method opt-in into this capability on startup.
2018-01-03reimplement and simplify mirror:// methodDavid Kalnischkies
Embedding an entire acquire stack and HTTP logic in the mirror method made it rather heavy weight and fragile. This reimplement goes the other way by doing only the bare minimum in the method itself and instead redirect the actual download of files to their proper methods. The reimplementation drops the (in the real world) unused query-string feature as it isn't really implementable in the new architecture.
2018-01-03allow a method to request auxiliary filesDavid Kalnischkies
If a method needs a file to operate like e.g. mirror needs to get a list of mirrors before it can redirect the the actual requests to them. That could easily be solved by moving the logic into libapt directly, but by allowing a method to request other methods to do something we can keep this logic contained in the method and allow e.g. also methods which perform binary patching or similar things. Previously they would need to implement their own acquire system inside the existing one which in all likelyhood will not support the same features and methods nor operate with similar security compared to what we have already running 'above' the requesting method. That said, to avoid methods producing conflicts with "proper" files we are downloading a new directory is introduced to keep the auxiliary files in. [The message magic number 351 is a tribute to the german Grundgesetz article 35 paragraph 1 which defines that all authorities of the state(s) help each other on request.]
2018-01-03refactor message generation for methodsDavid Kalnischkies
The format isn't too hard to get right, but it gets funny with multiline fields (which we don't really have yet) and its just easier to deal with it once and for all which can be reused for more messages later.
2018-01-02Support cleartext signed InRelease files with CRLF line endingsDavid Kalnischkies
Commit 89c4c588b275 ("fix from David Kalnischkies for the InRelease gpg verification code (LP: #784473)") amended verification of cleartext signatures by a check whether the file to be verified actually starts with "-----BEGIN PGP SIGNATURE-----\n". However cleartext signed InRelease files have been found in the wild which use \r\n as line ending for this armor header line, presumably generated by a Windows PGP client. Such files are incorrectly deemed unsigned and result in the following (misleading) error: Clearsigned file isn't valid, got 'NOSPLIT' (does the network require authentication?) RFC 4880 specifies in 6.2 Forming ASCII Armor: That is to say, there is always a line ending preceding the starting five dashes, and following the ending five dashes. The header lines, therefore, MUST start at the beginning of a line, and MUST NOT have text other than whitespace following them on the same line. RFC 4880 does not seem to specify whether LF or CRLF is used as line ending for armor headers, but CR is generally considered whitespace (e.g. "man perlrecharclass"), hence using CRLF is legal even under the assumption that LF must be used. SplitClearSignedFile() is stripping whitespace (including CR) on lineend already before matching the string, so StartsWithGPGClearTextSignature() is adapted to use the same ignoring. As the earlier method is responsible for what apt will end up actually parsing nowadays as signed/unsigned this change has no implications for security. Thanks: Lukas Wunner for detailed report & initial patch! References: 89c4c588b275d098af33f36eeddea6fd75068342 Closes: 884922
2017-12-24do not remap current files if nullptrs in cache generationDavid Kalnischkies
If the cache needs to grow to make room to insert volatile files like deb files into the cache we were remapping null-pointers making them non-null-pointers in the process causing trouble later on. Only the current Releasefile pointer can currently legally be a nullpointer as volatile files have no release file they belong to, but for safety the pointer to the current Packages file is equally guarded. The option APT::Cache-Start can be used to workaround this problem. Reported-By: Mattia Rizzolo on IRC
2017-12-14remove pointless APT_PURE from void functionsDavid Kalnischkies
Earlier gcc versions used to complain that you should add them althrough there isn't a lot of point to it if you think about it, but now gcc (>= 8) complains about the attribute being present. warning: ‘pure’ attribute on function returning ‘void’ [-Wattributes] Reported-By: gcc -Wattributes Gbp-Dch: Ignore
2017-12-13implement fallback to alternative URIs for all itemsDavid Kalnischkies
For deb files we always supported falling back from one server to the other if one failed to download the deb, but that was hardwired in the handling of this specific item. Moving this alongside the retry infrastructure we can implement it for all items and allow methods to use this as well by providing additional URIs in a redirect.
2017-12-13give the methods more metadata about the files to acquireDavid Kalnischkies
We have quite a bit of metadata available for the files we acquire, but the methods weren't told about it and got just the URI. That is indeed fine for most, but to avoid methods trying to parse the metadata out of the provided URIs (and fail horribly in edgecases) we can just as well be nice and tell them stuff directly.
2017-12-13implement Acquire::Retries support for all itemsDavid Kalnischkies
Moving the Retry-implementation from individual items to the worker implementation not only gives every file retry capability instead of just a selected few but also avoids needing to implement it in each item (incorrectly).
2017-12-13support multiline values in LookupTagDavid Kalnischkies
LookupTag is a little helper to deal with rfc822-style strings we use in apt e.g. to pass acquire messages around for cases in which our usual rfc822 parser is too heavy. All the fields it had to deal with so far were single line, but if they aren't it should really produce the right output and not just return the first line. Error messages are a prime candidate for becoming multiline as at the moment they are stripped of potential newlines due to the previous insufficiency of LookupTag.
2017-12-13deal with floats without old-style castDavid Kalnischkies
We have no speed problem with handling floats/doubles in our progress handling, but that shouldn't prevent us from cleaning up the handling slightly to avoid unclean casting to ints. Reported-By: gcc -Wdouble-promotion -Wold-style-cast
2017-12-13avoid some useless casts reported by -Wuseless-castDavid Kalnischkies
The casts are useless, but the reports show some where we can actually improve the code by replacing them with better alternatives like converting whatever int type into a string instead of casting to a specific one which might in the future be too small. Reported-By: gcc -Wuseless-cast
2017-12-13convert various c-style casts to C++-styleDavid Kalnischkies
gcc was warning about ignored type qualifiers for all of them due to the last 'const', so dropping that and converting to static_cast in the process removes the here harmless warning to avoid hidden real issues in them later on. Reported-By: gcc Gbp-Dch: Ignore
2017-12-13deprecate the single-line deprecation ignoring macroDavid Kalnischkies
gcc has problems understanding this construct and additionally thinks it would produce multiple lines and stuff, so to keep using it isn't really worth it for the few instances we have: We can just write the long form there which works better. Reported-By: gcc Gbp-Dch: Ignore