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673472a Johannes Schindelin 06 February 2023, 08:37:53 UTC Git 2.36.5 Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> 06 February 2023, 08:37:53 UTC
4084321 Johannes Schindelin 06 February 2023, 08:37:52 UTC Sync with 2.35.7 * maint-2.35: Git 2.35.7 Git 2.34.7 http: support CURLOPT_PROTOCOLS_STR http: prefer CURLOPT_SEEKFUNCTION to CURLOPT_IOCTLFUNCTION http-push: prefer CURLOPT_UPLOAD to CURLOPT_PUT Git 2.33.7 Git 2.32.6 Git 2.31.7 Git 2.30.8 apply: fix writing behind newly created symbolic links dir-iterator: prevent top-level symlinks without FOLLOW_SYMLINKS clone: delay picking a transport until after get_repo_path() t5619: demonstrate clone_local() with ambiguous transport 06 February 2023, 08:37:52 UTC
b7a92d0 Johannes Schindelin 06 February 2023, 08:29:45 UTC Git 2.35.7 Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> 06 February 2023, 08:29:45 UTC
6a53a59 Johannes Schindelin 06 February 2023, 08:29:44 UTC Sync with 2.34.7 * maint-2.34: Git 2.34.7 http: support CURLOPT_PROTOCOLS_STR http: prefer CURLOPT_SEEKFUNCTION to CURLOPT_IOCTLFUNCTION http-push: prefer CURLOPT_UPLOAD to CURLOPT_PUT Git 2.33.7 Git 2.32.6 Git 2.31.7 Git 2.30.8 apply: fix writing behind newly created symbolic links dir-iterator: prevent top-level symlinks without FOLLOW_SYMLINKS clone: delay picking a transport until after get_repo_path() t5619: demonstrate clone_local() with ambiguous transport 06 February 2023, 08:29:44 UTC
91da4a2 Johannes Schindelin 06 February 2023, 08:29:17 UTC Git 2.34.7 Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> 06 February 2023, 08:29:17 UTC
a7237f5 Johannes Schindelin 06 February 2023, 08:29:16 UTC Sync with 2.33.7 * maint-2.33: Git 2.33.7 Git 2.32.6 Git 2.31.7 Git 2.30.8 apply: fix writing behind newly created symbolic links dir-iterator: prevent top-level symlinks without FOLLOW_SYMLINKS clone: delay picking a transport until after get_repo_path() t5619: demonstrate clone_local() with ambiguous transport 06 February 2023, 08:29:16 UTC
bd6d3de Junio C Hamano 20 January 2023, 23:36:21 UTC Merge branch 'jk/curl-avoid-deprecated-api' Deal with a few deprecation warning from cURL library. * jk/curl-avoid-deprecated-api: http: support CURLOPT_PROTOCOLS_STR http: prefer CURLOPT_SEEKFUNCTION to CURLOPT_IOCTLFUNCTION http-push: prefer CURLOPT_UPLOAD to CURLOPT_PUT 06 February 2023, 08:27:41 UTC
f44e6a2 Jeff King 17 January 2023, 03:04:48 UTC http: support CURLOPT_PROTOCOLS_STR The CURLOPT_PROTOCOLS (and matching CURLOPT_REDIR_PROTOCOLS) flag was deprecated in curl 7.85.0, and using it generate compiler warnings as of curl 7.87.0. The path forward is to use CURLOPT_PROTOCOLS_STR, but we can't just do so unilaterally, as it was only introduced less than a year ago in 7.85.0. Until that version becomes ubiquitous, we have to either disable the deprecation warning or conditionally use the "STR" variant on newer versions of libcurl. This patch switches to the new variant, which is nice for two reasons: - we don't have to worry that silencing curl's deprecation warnings might cause us to miss other more useful ones - we'd eventually want to move to the new variant anyway, so this gets us set up (albeit with some extra ugly boilerplate for the conditional) There are a lot of ways to split up the two cases. One way would be to abstract the storage type (strbuf versus a long), how to append (strbuf_addstr vs bitwise OR), how to initialize, which CURLOPT to use, and so on. But the resulting code looks pretty magical: GIT_CURL_PROTOCOL_TYPE allowed = GIT_CURL_PROTOCOL_TYPE_INIT; if (...http is allowed...) GIT_CURL_PROTOCOL_APPEND(&allowed, "http", CURLOPT_HTTP); and you end up with more "#define GIT_CURL_PROTOCOL_TYPE" macros than actual code. On the other end of the spectrum, we could just implement two separate functions, one that handles a string list and one that handles bits. But then we end up repeating our list of protocols (http, https, ftp, ftp). This patch takes the middle ground. The run-time code is always there to handle both types, and we just choose which one to feed to curl. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com> Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> 06 February 2023, 08:27:09 UTC
4bd481e Jeff King 17 January 2023, 03:04:44 UTC http: prefer CURLOPT_SEEKFUNCTION to CURLOPT_IOCTLFUNCTION The IOCTLFUNCTION option has been deprecated, and generates a compiler warning in recent versions of curl. We can switch to using SEEKFUNCTION instead. It was added in 2008 via curl 7.18.0; our INSTALL file already indicates we require at least curl 7.19.4. But there's one catch: curl says we should use CURL_SEEKFUNC_{OK,FAIL}, and those didn't arrive until 7.19.5. One workaround would be to use a bare 0/1 here (or define our own macros). But let's just bump the minimum required version to 7.19.5. That version is only a minor version bump from our existing requirement, and is only a 2 month time bump for versions that are almost 13 years old. So it's not likely that anybody cares about the distinction. Switching means we have to rewrite the ioctl functions into seek functions. In some ways they are simpler (seeking is the only operation), but in some ways more complex (the ioctl allowed only a full rewind, but now we can seek to arbitrary offsets). Curl will only ever use SEEK_SET (per their documentation), so I didn't bother implementing anything else, since it would naturally be completely untested. This seems unlikely to change, but I added an assertion just in case. Likewise, I doubt curl will ever try to seek outside of the buffer sizes we've told it, but I erred on the defensive side here, rather than do an out-of-bounds read. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com> Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> 06 February 2023, 08:27:09 UTC
4fab049 Jeff King 17 January 2023, 03:04:38 UTC http-push: prefer CURLOPT_UPLOAD to CURLOPT_PUT The two options do exactly the same thing, but the latter has been deprecated and in recent versions of curl may produce a compiler warning. Since the UPLOAD form is available everywhere (it was introduced in the year 2000 by curl 7.1), we can just switch to it. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com> Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> 06 February 2023, 08:27:08 UTC
ed4404a Johannes Schindelin 06 February 2023, 08:25:58 UTC Git 2.33.7 Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> 06 February 2023, 08:25:58 UTC
87248c5 Johannes Schindelin 06 February 2023, 08:25:56 UTC Sync with 2.32.6 * maint-2.32: Git 2.32.6 Git 2.31.7 Git 2.30.8 apply: fix writing behind newly created symbolic links dir-iterator: prevent top-level symlinks without FOLLOW_SYMLINKS clone: delay picking a transport until after get_repo_path() t5619: demonstrate clone_local() with ambiguous transport 06 February 2023, 08:25:56 UTC
2aedeff Johannes Schindelin 06 February 2023, 08:25:09 UTC Git 2.32.6 Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> 06 February 2023, 08:25:09 UTC
aeb93d7 Johannes Schindelin 06 February 2023, 08:25:08 UTC Sync with 2.31.7 * maint-2.31: Git 2.31.7 Git 2.30.8 apply: fix writing behind newly created symbolic links dir-iterator: prevent top-level symlinks without FOLLOW_SYMLINKS clone: delay picking a transport until after get_repo_path() t5619: demonstrate clone_local() with ambiguous transport 06 February 2023, 08:25:08 UTC
0bbcf95 Johannes Schindelin 06 February 2023, 08:24:07 UTC Git 2.31.7 Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> 06 February 2023, 08:24:07 UTC
e14d6b8 Johannes Schindelin 06 February 2023, 08:24:06 UTC Sync with 2.30.8 * maint-2.30: Git 2.30.8 apply: fix writing behind newly created symbolic links dir-iterator: prevent top-level symlinks without FOLLOW_SYMLINKS clone: delay picking a transport until after get_repo_path() t5619: demonstrate clone_local() with ambiguous transport 06 February 2023, 08:24:06 UTC
394a759 Junio C Hamano 03 February 2023, 22:58:10 UTC Git 2.30.8 Signed-off-by: Junio C Hamano <gitster@pobox.com> 06 February 2023, 08:14:45 UTC
a3033a6 Junio C Hamano 03 February 2023, 22:57:27 UTC Merge branch 'ps/apply-beyond-symlink' into maint-2.30 Fix a vulnerability (CVE-2023-23946) that allows crafted input to trick `git apply` into writing files outside of the working tree. * ps/apply-beyond-symlink: dir-iterator: prevent top-level symlinks without FOLLOW_SYMLINKS Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> 06 February 2023, 08:12:16 UTC
2c9a4c7 Taylor Blau 25 January 2023, 19:58:38 UTC Merge branch 'tb/clone-local-symlinks' into maint-2.30 Resolve a security vulnerability (CVE-2023-22490) where `clone_local()` is used in conjunction with non-local transports, leading to arbitrary path exfiltration. * tb/clone-local-symlinks: dir-iterator: prevent top-level symlinks without FOLLOW_SYMLINKS clone: delay picking a transport until after get_repo_path() t5619: demonstrate clone_local() with ambiguous transport 06 February 2023, 08:09:14 UTC
fade728 Patrick Steinhardt 02 February 2023, 10:54:34 UTC apply: fix writing behind newly created symbolic links When writing files git-apply(1) initially makes sure that none of the files it is about to create are behind a symlink: ``` $ git init repo Initialized empty Git repository in /tmp/repo/.git/ $ cd repo/ $ ln -s dir symlink $ git apply - <<EOF diff --git a/symlink/file b/symlink/file new file mode 100644 index 0000000..e69de29 EOF error: affected file 'symlink/file' is beyond a symbolic link ``` This safety mechanism is crucial to ensure that we don't write outside of the repository's working directory. It can be fooled though when the patch that is being applied creates the symbolic link in the first place, which can lead to writing files in arbitrary locations. Fix this by checking whether the path we're about to create is beyond a symlink or not. Tightening these checks like this should be fine as we already have these precautions in Git as explained above. Ideally, we should update the check we do up-front before starting to reflect the computed changes to the working tree so that we catch this case as well, but as part of embargoed security work, adding an equivalent check just before we try to write out a file should serve us well as a reasonable first step. Digging back into history shows that this vulnerability has existed since at least Git v2.9.0. As Git v2.8.0 and older don't build on my system anymore I cannot tell whether older versions are affected, as well. Reported-by: Joern Schneeweisz <jschneeweisz@gitlab.com> Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com> 03 February 2023, 22:41:31 UTC
bffc762 Taylor Blau 25 January 2023, 00:43:51 UTC dir-iterator: prevent top-level symlinks without FOLLOW_SYMLINKS When using the dir_iterator API, we first stat(2) the base path, and then use that as a starting point to enumerate the directory's contents. If the directory contains symbolic links, we will immediately die() upon encountering them without the `FOLLOW_SYMLINKS` flag. The same is not true when resolving the top-level directory, though. As explained in a previous commit, this oversight in 6f054f9fb3 (builtin/clone.c: disallow `--local` clones with symlinks, 2022-07-28) can be used as an attack vector to include arbitrary files on a victim's filesystem from outside of the repository. Prevent resolving top-level symlinks unless the FOLLOW_SYMLINKS flag is given, which will cause clones of a repository with a symlink'd "$GIT_DIR/objects" directory to fail. Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com> 25 January 2023, 00:52:16 UTC
cf8f6ce Taylor Blau 25 January 2023, 00:43:48 UTC clone: delay picking a transport until after get_repo_path() In the previous commit, t5619 demonstrates an issue where two calls to `get_repo_path()` could trick Git into using its local clone mechanism in conjunction with a non-local transport. That sequence is: - the starting state is that the local path https:/example.com/foo is a symlink that points to ../../../.git/modules/foo. So it's dangling. - get_repo_path() sees that no such path exists (because it's dangling), and thus we do not canonicalize it into an absolute path - because we're using --separate-git-dir, we create .git/modules/foo. Now our symlink is no longer dangling! - we pass the url to transport_get(), which sees it as an https URL. - we call get_repo_path() again, on the url. This second call was introduced by f38aa83f9a (use local cloning if insteadOf makes a local URL, 2014-07-17). The idea is that we want to pull the url fresh from the remote.c API, because it will apply any aliases. And of course now it sees that there is a local file, which is a mismatch with the transport we already selected. The issue in the above sequence is calling `transport_get()` before deciding whether or not the repository is indeed local, and not passing in an absolute path if it is local. This is reminiscent of a similar bug report in [1], where it was suggested to perform the `insteadOf` lookup earlier. Taking that approach may not be as straightforward, since the intent is to store the original URL in the config, but to actually fetch from the insteadOf one, so conflating the two early on is a non-starter. Note: we pass the path returned by `get_repo_path(remote->url[0])`, which should be the same as `repo_name` (aside from any `insteadOf` rewrites). We *could* pass `absolute_pathdup()` of the same argument, which 86521acaca (Bring local clone's origin URL in line with that of a remote clone, 2008-09-01) indicates may differ depending on the presence of ".git/" for a non-bare repo. That matters for forming relative submodule paths, but doesn't matter for the second call, since we're just feeding it to the transport code, which is fine either way. [1]: https://lore.kernel.org/git/CAMoD=Bi41mB3QRn3JdZL-FGHs4w3C2jGpnJB-CqSndO7FMtfzA@mail.gmail.com/ Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com> 25 January 2023, 00:52:16 UTC
58325b9 Taylor Blau 25 January 2023, 00:43:45 UTC t5619: demonstrate clone_local() with ambiguous transport When cloning a repository, Git must determine (a) what transport mechanism to use, and (b) whether or not the clone is local. Since f38aa83f9a (use local cloning if insteadOf makes a local URL, 2014-07-17), the latter check happens after the remote has been initialized, and references the remote's URL instead of the local path. This is done to make it possible for a `url.<base>.insteadOf` rule to convert a remote URL into a local one, in which case the `clone_local()` mechanism should be used. However, with a specially crafted repository, Git can be tricked into using a non-local transport while still setting `is_local` to "1" and using the `clone_local()` optimization. The below test case demonstrates such an instance, and shows that it can be used to include arbitrary (known) paths in the working copy of a cloned repository on a victim's machine[^1], even if local file clones are forbidden by `protocol.file.allow`. This happens in a few parts: 1. We first call `get_repo_path()` to see if the remote is a local path. If it is, we replace the repo name with its absolute path. 2. We then call `transport_get()` on the repo name and decide how to access it. If it was turned into an absolute path in the previous step, then we should always treat it like a file. 3. We use `get_repo_path()` again, and set `is_local` as appropriate. But it's already too late to rewrite the repo name as an absolute path, since we've already fed it to the transport code. The attack works by including a submodule whose URL corresponds to a path on disk. In the below example, the repository "sub" is reachable via the dumb HTTP protocol at (something like): http://127.0.0.1:NNNN/dumb/sub.git However, the path "http:/127.0.0.1:NNNN/dumb" (that is, a top-level directory called "http:", then nested directories "127.0.0.1:NNNN", and "dumb") exists within the repository, too. To determine this, it first picks the appropriate transport, which is dumb HTTP. It then uses the remote's URL in order to determine whether the repository exists locally on disk. However, the malicious repository also contains an embedded stub repository which is the target of a symbolic link at the local path corresponding to the "sub" repository on disk (i.e., there is a symbolic link at "http:/127.0.0.1/dumb/sub.git", pointing to the stub repository via ".git/modules/sub/../../../repo"). This stub repository fools Git into thinking that a local repository exists at that URL and thus can be cloned locally. The affected call is in `get_repo_path()`, which in turn calls `get_repo_path_1()`, which locates a valid repository at that target. This then causes Git to set the `is_local` variable to "1", and in turn instructs Git to clone the repository using its local clone optimization via the `clone_local()` function. The exploit comes into play because the stub repository's top-level "$GIT_DIR/objects" directory is a symbolic link which can point to an arbitrary path on the victim's machine. `clone_local()` resolves the top-level "objects" directory through a `stat(2)` call, meaning that we read through the symbolic link and copy or hardlink the directory contents at the destination of the link. In other words, we can get steps (1) and (3) to disagree by leveraging the dangling symlink to pick a non-local transport in the first step, and then set is_local to "1" in the third step when cloning with `--separate-git-dir`, which makes the symlink non-dangling. This can result in data-exfiltration on the victim's machine when sensitive data is at a known path (e.g., "/home/$USER/.ssh"). The appropriate fix is two-fold: - Resolve the transport later on (to avoid using the local clone optimization with a non-local transport). - Avoid reading through the top-level "objects" directory when (correctly) using the clone_local() optimization. This patch merely demonstrates the issue. The following two patches will implement each part of the above fix, respectively. [^1]: Provided that any target directory does not contain symbolic links, in which case the changes from 6f054f9fb3 (builtin/clone.c: disallow `--local` clones with symlinks, 2022-07-28) will abort the clone. Reported-by: yvvdwf <yvvdwf@gmail.com> Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com> 25 January 2023, 00:52:16 UTC
5c1fc48 Junio C Hamano 19 January 2023, 21:48:08 UTC Sync with maint-2.35 * maint-2.35: attr: adjust a mismatched data type 19 January 2023, 21:48:08 UTC
c508c30 Junio C Hamano 19 January 2023, 21:48:00 UTC Sync with maint-2.34 * maint-2.34: attr: adjust a mismatched data type 19 January 2023, 21:48:00 UTC
f39fe8f Junio C Hamano 19 January 2023, 21:47:42 UTC Sync with maint-2.33 * maint-2.33: attr: adjust a mismatched data type 19 January 2023, 21:47:42 UTC
25d7cb6 Junio C Hamano 19 January 2023, 21:46:04 UTC Sync with maint-2.32 * maint-2.32: attr: adjust a mismatched data type 19 January 2023, 21:46:04 UTC
012e0d7 Junio C Hamano 19 January 2023, 21:45:37 UTC Sync with maint-2.31 * maint-2.31: attr: adjust a mismatched data type 19 January 2023, 21:45:37 UTC
f8bf6b8 Junio C Hamano 19 January 2023, 21:45:23 UTC Sync with maint-2.30 * maint-2.30: attr: adjust a mismatched data type 19 January 2023, 21:45:23 UTC
0227130 Johannes Schindelin 12 January 2023, 00:05:02 UTC attr: adjust a mismatched data type On platforms where `size_t` does not have the same width as `unsigned long`, passing a pointer to the former when a pointer to the latter is expected can lead to problems. Windows and 32-bit Linux are among the affected platforms. In this instance, we want to store the size of the blob that was read in that variable. However, `read_blob_data_from_index()` passes that pointer to `read_object_file()` which expects an `unsigned long *`. Which means that on affected platforms, the variable is not fully populated and part of its value is left uninitialized. (On Big-Endian platforms, this problem would be even worse.) The consequence is that depending on the uninitialized memory's contents, we may erroneously reject perfectly fine attributes. Let's address this by passing a pointer to a variable of the expected data type. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com> 19 January 2023, 21:38:06 UTC
ad949b2 Junio C Hamano 13 December 2022, 12:19:24 UTC Git 2.36.4 Signed-off-by: Junio C Hamano <gitster@pobox.com> 13 December 2022, 12:19:24 UTC
8253c00 Junio C Hamano 13 December 2022, 12:19:11 UTC Merge branch 'maint-2.35' into maint-2.36 13 December 2022, 12:19:11 UTC
02f4981 Junio C Hamano 13 December 2022, 12:17:26 UTC Git 2.35.6 Signed-off-by: Junio C Hamano <gitster@pobox.com> 13 December 2022, 12:17:26 UTC
fbabbc3 Junio C Hamano 13 December 2022, 12:17:10 UTC Merge branch 'maint-2.34' into maint-2.35 13 December 2022, 12:17:10 UTC
6c94669 Junio C Hamano 13 December 2022, 12:15:39 UTC Git 2.34.6 Signed-off-by: Junio C Hamano <gitster@pobox.com> 13 December 2022, 12:15:39 UTC
3748b5b Junio C Hamano 13 December 2022, 12:15:22 UTC Merge branch 'maint-2.33' into maint-2.34 13 December 2022, 12:15:22 UTC
7fe9bf5 Junio C Hamano 13 December 2022, 12:13:48 UTC Git 2.33.6 Signed-off-by: Junio C Hamano <gitster@pobox.com> 13 December 2022, 12:13:48 UTC
5f22dcc Junio C Hamano 13 December 2022, 12:13:11 UTC Sync with Git 2.32.5 13 December 2022, 12:13:11 UTC
d96ea53 Junio C Hamano 13 December 2022, 12:10:27 UTC Git 2.32.5 Signed-off-by: Junio C Hamano <gitster@pobox.com> 13 December 2022, 12:10:27 UTC
32e357b Junio C Hamano 13 December 2022, 12:09:56 UTC Merge branch 'ps/attr-limits-with-fsck' into maint-2.32 13 December 2022, 12:09:56 UTC
8a755ed Junio C Hamano 13 December 2022, 12:09:40 UTC Sync with Git 2.31.6 13 December 2022, 12:09:40 UTC
82689d5 Junio C Hamano 13 December 2022, 12:04:03 UTC Git 2.31.6 Signed-off-by: Junio C Hamano <gitster@pobox.com> 13 December 2022, 12:04:03 UTC
1612876 Junio C Hamano 13 December 2022, 12:02:20 UTC Sync with Git 2.30.7 13 December 2022, 12:02:20 UTC
b7b37a3 Junio C Hamano 13 December 2022, 11:56:43 UTC Git 2.30.7 Signed-off-by: Junio C Hamano <gitster@pobox.com> 13 December 2022, 11:56:43 UTC
27ab478 Patrick Steinhardt 01 December 2022, 14:46:09 UTC fsck: implement checks for gitattributes Recently, a vulnerability was reported that can lead to an out-of-bounds write when reading an unreasonably large gitattributes file. The root cause of this error are multiple integer overflows in different parts of the code when there are either too many lines, when paths are too long, when attribute names are too long, or when there are too many attributes declared for a pattern. As all of these are related to size, it seems reasonable to restrict the size of the gitattributes file via git-fsck(1). This allows us to both stop distributing known-vulnerable objects via common hosting platforms that have fsck enabled, and users to protect themselves by enabling the `fetch.fsckObjects` config. There are basically two checks: 1. We verify that size of the gitattributes file is smaller than 100MB. 2. We verify that the maximum line length does not exceed 2048 bytes. With the preceding commits, both of these conditions would cause us to either ignore the complete gitattributes file or blob in the first case, or the specific line in the second case. Now with these consistency checks added, we also grow the ability to stop distributing such files in the first place when `receive.fsckObjects` is enabled. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com> 09 December 2022, 08:07:04 UTC
f8587c3 Patrick Steinhardt 01 December 2022, 14:46:05 UTC fsck: move checks for gitattributes Move the checks for gitattributes so that they can be extended more readily. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com> 09 December 2022, 08:05:00 UTC
a59a8c6 Patrick Steinhardt 01 December 2022, 14:46:01 UTC fsck: pull out function to check a set of blobs In `fsck_finish()` we check all blobs for consistency that we have found during the tree walk, but that haven't yet been checked. This is only required for gitmodules right now, but will also be required for a new check for gitattributes. Pull out a function `fsck_blobs()` that allows the caller to check a set of blobs for consistency. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com> 09 December 2022, 08:05:00 UTC
bb3a926 Patrick Steinhardt 01 December 2022, 14:45:57 UTC fsck: refactor `fsck_blob()` to allow for more checks In general, we don't need to validate blob contents as they are opaque blobs about whose content Git doesn't need to care about. There are some exceptions though when blobs are linked into trees so that they would be interpreted by Git. We only have a single such check right now though, which is the one for gitmodules that has been added in the context of CVE-2018-11235. Now we have found another vulnerability with gitattributes that can lead to out-of-bounds writes and reads. So let's refactor `fsck_blob()` so that it is more extensible and can check different types of blobs. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com> 09 December 2022, 08:05:00 UTC
e0bfc0b Junio C Hamano 09 December 2022, 08:03:49 UTC Merge branch 'ps/attr-limits' into maint-2.32 09 December 2022, 08:03:49 UTC
6662a83 Junio C Hamano 09 December 2022, 07:05:52 UTC Merge branch 'ps/attr-limits' into maint-2.30 09 December 2022, 07:05:52 UTC
3305300 Junio C Hamano 09 December 2022, 07:02:39 UTC Merge branch 'ps/format-padding-fix' into maint-2.30 09 December 2022, 07:02:39 UTC
304a50a Patrick Steinhardt 01 December 2022, 14:47:23 UTC pretty: restrict input lengths for padding and wrapping formats Both the padding and wrapping formatting directives allow the caller to specify an integer that ultimately leads to us adding this many chars to the result buffer. As a consequence, it is trivial to e.g. allocate 2GB of RAM via a single formatting directive and cause resource exhaustion on the machine executing this logic. Furthermore, it is debatable whether there are any sane usecases that require the user to pad data to 2GB boundaries or to indent wrapped data by 2GB. Restrict the input sizes to 16 kilobytes at a maximum to limit the amount of bytes that can be requested by the user. This is not meant as a fix because there are ways to trivially amplify the amount of data we generate via formatting directives; the real protection is achieved by the changes in previous steps to catch and avoid integer wraparound that causes us to under-allocate and access beyond the end of allocated memory reagions. But having such a limit significantly helps fuzzing the pretty format, because the fuzzer is otherwise quite fast to run out-of-memory as it discovers these formatters. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com> 09 December 2022, 05:26:21 UTC
f930a23 Patrick Steinhardt 01 December 2022, 14:47:15 UTC utf8: refactor `strbuf_utf8_replace` to not rely on preallocated buffer In `strbuf_utf8_replace`, we preallocate the destination buffer and then use `memcpy` to copy bytes into it at computed offsets. This feels rather fragile and is hard to understand at times. Refactor the code to instead use `strbuf_add` and `strbuf_addstr` so that we can be sure that there is no possibility to perform an out-of-bounds write. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com> 09 December 2022, 05:26:21 UTC
81c2d4c Patrick Steinhardt 01 December 2022, 14:47:10 UTC utf8: fix checking for glyph width in `strbuf_utf8_replace()` In `strbuf_utf8_replace()`, we call `utf8_width()` to compute the width of the current glyph. If the glyph is a control character though it can be that `utf8_width()` returns `-1`, but because we assign this value to a `size_t` the conversion will cause us to underflow. This bug can easily be triggered with the following command: $ git log --pretty='format:xxx%<|(1,trunc)%x10' >From all I can see though this seems to be a benign underflow that has no security-related consequences. Fix the bug by using an `int` instead. When we see a control character, we now copy it into the target buffer but don't advance the current width of the string. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com> 09 December 2022, 05:26:21 UTC
937b71c Patrick Steinhardt 01 December 2022, 14:47:04 UTC utf8: fix overflow when returning string width The return type of both `utf8_strwidth()` and `utf8_strnwidth()` is `int`, but we operate on string lengths which are typically of type `size_t`. This means that when the string is longer than `INT_MAX`, we will overflow and thus return a negative result. This can lead to an out-of-bounds write with `--pretty=format:%<1)%B` and a commit message that is 2^31+1 bytes long: ================================================================= ==26009==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x603000001168 at pc 0x7f95c4e5f427 bp 0x7ffd8541c900 sp 0x7ffd8541c0a8 WRITE of size 2147483649 at 0x603000001168 thread T0 #0 0x7f95c4e5f426 in __interceptor_memcpy /usr/src/debug/gcc/libsanitizer/sanitizer_common/sanitizer_common_interceptors.inc:827 #1 0x5612bbb1068c in format_and_pad_commit pretty.c:1763 #2 0x5612bbb1087a in format_commit_item pretty.c:1801 #3 0x5612bbc33bab in strbuf_expand strbuf.c:429 #4 0x5612bbb110e7 in repo_format_commit_message pretty.c:1869 #5 0x5612bbb12d96 in pretty_print_commit pretty.c:2161 #6 0x5612bba0a4d5 in show_log log-tree.c:781 #7 0x5612bba0d6c7 in log_tree_commit log-tree.c:1117 #8 0x5612bb691ed5 in cmd_log_walk_no_free builtin/log.c:508 #9 0x5612bb69235b in cmd_log_walk builtin/log.c:549 #10 0x5612bb6951a2 in cmd_log builtin/log.c:883 #11 0x5612bb56c993 in run_builtin git.c:466 #12 0x5612bb56d397 in handle_builtin git.c:721 #13 0x5612bb56db07 in run_argv git.c:788 #14 0x5612bb56e8a7 in cmd_main git.c:923 #15 0x5612bb803682 in main common-main.c:57 #16 0x7f95c4c3c28f (/usr/lib/libc.so.6+0x2328f) #17 0x7f95c4c3c349 in __libc_start_main (/usr/lib/libc.so.6+0x23349) #18 0x5612bb5680e4 in _start ../sysdeps/x86_64/start.S:115 0x603000001168 is located 0 bytes to the right of 24-byte region [0x603000001150,0x603000001168) allocated by thread T0 here: #0 0x7f95c4ebe7ea in __interceptor_realloc /usr/src/debug/gcc/libsanitizer/asan/asan_malloc_linux.cpp:85 #1 0x5612bbcdd556 in xrealloc wrapper.c:136 #2 0x5612bbc310a3 in strbuf_grow strbuf.c:99 #3 0x5612bbc32acd in strbuf_add strbuf.c:298 #4 0x5612bbc33aec in strbuf_expand strbuf.c:418 #5 0x5612bbb110e7 in repo_format_commit_message pretty.c:1869 #6 0x5612bbb12d96 in pretty_print_commit pretty.c:2161 #7 0x5612bba0a4d5 in show_log log-tree.c:781 #8 0x5612bba0d6c7 in log_tree_commit log-tree.c:1117 #9 0x5612bb691ed5 in cmd_log_walk_no_free builtin/log.c:508 #10 0x5612bb69235b in cmd_log_walk builtin/log.c:549 #11 0x5612bb6951a2 in cmd_log builtin/log.c:883 #12 0x5612bb56c993 in run_builtin git.c:466 #13 0x5612bb56d397 in handle_builtin git.c:721 #14 0x5612bb56db07 in run_argv git.c:788 #15 0x5612bb56e8a7 in cmd_main git.c:923 #16 0x5612bb803682 in main common-main.c:57 #17 0x7f95c4c3c28f (/usr/lib/libc.so.6+0x2328f) SUMMARY: AddressSanitizer: heap-buffer-overflow /usr/src/debug/gcc/libsanitizer/sanitizer_common/sanitizer_common_interceptors.inc:827 in __interceptor_memcpy Shadow bytes around the buggy address: 0x0c067fff81d0: fd fd fd fa fa fa fd fd fd fa fa fa fd fd fd fa 0x0c067fff81e0: fa fa fd fd fd fd fa fa fd fd fd fd fa fa fd fd 0x0c067fff81f0: fd fa fa fa fd fd fd fa fa fa fd fd fd fa fa fa 0x0c067fff8200: fd fd fd fa fa fa fd fd fd fd fa fa 00 00 00 fa 0x0c067fff8210: fa fa fd fd fd fa fa fa fd fd fd fa fa fa fd fd =>0x0c067fff8220: fd fa fa fa fd fd fd fa fa fa 00 00 00[fa]fa fa 0x0c067fff8230: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa 0x0c067fff8240: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa 0x0c067fff8250: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa 0x0c067fff8260: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa 0x0c067fff8270: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa Shadow byte legend (one shadow byte represents 8 application bytes): Addressable: 00 Partially addressable: 01 02 03 04 05 06 07 Heap left redzone: fa Freed heap region: fd Stack left redzone: f1 Stack mid redzone: f2 Stack right redzone: f3 Stack after return: f5 Stack use after scope: f8 Global redzone: f9 Global init order: f6 Poisoned by user: f7 Container overflow: fc Array cookie: ac Intra object redzone: bb ASan internal: fe Left alloca redzone: ca Right alloca redzone: cb ==26009==ABORTING Now the proper fix for this would be to convert both functions to return an `size_t` instead of an `int`. But given that this commit may be part of a security release, let's instead do the minimal viable fix and die in case we see an overflow. Add a test that would have previously caused us to crash. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com> 09 December 2022, 05:26:21 UTC
17d23e8 Patrick Steinhardt 01 December 2022, 14:47:00 UTC utf8: fix returning negative string width The `utf8_strnwidth()` function calls `utf8_width()` in a loop and adds its returned width to the end result. `utf8_width()` can return `-1` though in case it reads a control character, which means that the computed string width is going to be wrong. In the worst case where there are more control characters than non-control characters, we may even return a negative string width. Fix this bug by treating control characters as having zero width. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com> 09 December 2022, 05:26:21 UTC
522cc87 Patrick Steinhardt 01 December 2022, 14:46:53 UTC utf8: fix truncated string lengths in `utf8_strnwidth()` The `utf8_strnwidth()` function accepts an optional string length as input parameter. This parameter can either be set to `-1`, in which case we call `strlen()` on the input. Or it can be set to a positive integer that indicates a precomputed length, which callers typically compute by calling `strlen()` at some point themselves. The input parameter is an `int` though, whereas `strlen()` returns a `size_t`. This can lead to implementation-defined behaviour though when the `size_t` cannot be represented by the `int`. In the general case though this leads to wrap-around and thus to negative string sizes, which is sure enough to not lead to well-defined behaviour. Fix this by accepting a `size_t` instead of an `int` as string length. While this takes away the ability of callers to simply pass in `-1` as string length, it really is trivial enough to convert them to instead pass in `strlen()` instead. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com> 09 December 2022, 05:26:21 UTC
48050c4 Patrick Steinhardt 01 December 2022, 14:46:49 UTC pretty: fix integer overflow in wrapping format The `%w(width,indent1,indent2)` formatting directive can be used to rewrap text to a specific width and is designed after git-shortlog(1)'s `-w` parameter. While the three parameters are all stored as `size_t` internally, `strbuf_add_wrapped_text()` accepts integers as input. As a result, the casted integers may overflow. As these now-negative integers are later on passed to `strbuf_addchars()`, we will ultimately run into implementation-defined behaviour due to casting a negative number back to `size_t` again. On my platform, this results in trying to allocate 9000 petabyte of memory. Fix this overflow by using `cast_size_t_to_int()` so that we reject inputs that cannot be represented as an integer. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com> 09 December 2022, 05:26:21 UTC
1de69c0 Patrick Steinhardt 01 December 2022, 14:46:39 UTC pretty: fix adding linefeed when placeholder is not expanded When a formatting directive has a `+` or ` ` after the `%`, then we add either a line feed or space if the placeholder expands to a non-empty string. In specific cases though this logic doesn't work as expected, and we try to add the character even in the case where the formatting directive is empty. One such pattern is `%w(1)%+d%+w(2)`. `%+d` expands to reference names pointing to a certain commit, like in `git log --decorate`. For a tagged commit this would for example expand to `\n (tag: v1.0.0)`, which has a leading newline due to the `+` modifier and a space added by `%d`. Now the second wrapping directive will cause us to rewrap the text to `\n(tag:\nv1.0.0)`, which is one byte shorter due to the missing leading space. The code that handles the `+` magic now notices that the length has changed and will thus try to insert a leading line feed at the original posititon. But as the string was shortened, the original position is past the buffer's boundary and thus we die with an error. Now there are two issues here: 1. We check whether the buffer length has changed, not whether it has been extended. This causes us to try and add the character past the string boundary. 2. The current logic does not make any sense whatsoever. When the string got expanded due to the rewrap, putting the separator into the original position is likely to put it somewhere into the middle of the rewrapped contents. It is debatable whether `%+w()` makes any sense in the first place. Strictly speaking, the placeholder never expands to a non-empty string, and consequentially we shouldn't ever accept this combination. We thus fix the bug by simply refusing `%+w()`. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com> 09 December 2022, 05:26:21 UTC
f6e0b9f Patrick Steinhardt 01 December 2022, 14:46:34 UTC pretty: fix out-of-bounds read when parsing invalid padding format An out-of-bounds read can be triggered when parsing an incomplete padding format string passed via `--pretty=format` or in Git archives when files are marked with the `export-subst` gitattribute. This bug exists since we have introduced support for truncating output via the `trunc` keyword a7f01c6b4d (pretty: support truncating in %>, %< and %><, 2013-04-19). Before this commit, we used to find the end of the formatting string by using strchr(3P). This function returns a `NULL` pointer in case the character in question wasn't found. The subsequent check whether any character was found thus simply checked the returned pointer. After the commit we switched to strcspn(3P) though, which only returns the offset to the first found character or to the trailing NUL byte. As the end pointer is now computed by adding the offset to the start pointer it won't be `NULL` anymore, and as a consequence the check doesn't do anything anymore. The out-of-bounds data that is being read can in fact end up in the formatted string. As a consequence, it is possible to leak memory contents either by calling git-log(1) or via git-archive(1) when any of the archived files is marked with the `export-subst` gitattribute. ==10888==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x602000000398 at pc 0x7f0356047cb2 bp 0x7fff3ffb95d0 sp 0x7fff3ffb8d78 READ of size 1 at 0x602000000398 thread T0 #0 0x7f0356047cb1 in __interceptor_strchrnul /usr/src/debug/gcc/libsanitizer/sanitizer_common/sanitizer_common_interceptors.inc:725 #1 0x563b7cec9a43 in strbuf_expand strbuf.c:417 #2 0x563b7cda7060 in repo_format_commit_message pretty.c:1869 #3 0x563b7cda8d0f in pretty_print_commit pretty.c:2161 #4 0x563b7cca04c8 in show_log log-tree.c:781 #5 0x563b7cca36ba in log_tree_commit log-tree.c:1117 #6 0x563b7c927ed5 in cmd_log_walk_no_free builtin/log.c:508 #7 0x563b7c92835b in cmd_log_walk builtin/log.c:549 #8 0x563b7c92b1a2 in cmd_log builtin/log.c:883 #9 0x563b7c802993 in run_builtin git.c:466 #10 0x563b7c803397 in handle_builtin git.c:721 #11 0x563b7c803b07 in run_argv git.c:788 #12 0x563b7c8048a7 in cmd_main git.c:923 #13 0x563b7ca99682 in main common-main.c:57 #14 0x7f0355e3c28f (/usr/lib/libc.so.6+0x2328f) #15 0x7f0355e3c349 in __libc_start_main (/usr/lib/libc.so.6+0x23349) #16 0x563b7c7fe0e4 in _start ../sysdeps/x86_64/start.S:115 0x602000000398 is located 0 bytes to the right of 8-byte region [0x602000000390,0x602000000398) allocated by thread T0 here: #0 0x7f0356072faa in __interceptor_strdup /usr/src/debug/gcc/libsanitizer/asan/asan_interceptors.cpp:439 #1 0x563b7cf7317c in xstrdup wrapper.c:39 #2 0x563b7cd9a06a in save_user_format pretty.c:40 #3 0x563b7cd9b3e5 in get_commit_format pretty.c:173 #4 0x563b7ce54ea0 in handle_revision_opt revision.c:2456 #5 0x563b7ce597c9 in setup_revisions revision.c:2850 #6 0x563b7c9269e0 in cmd_log_init_finish builtin/log.c:269 #7 0x563b7c927362 in cmd_log_init builtin/log.c:348 #8 0x563b7c92b193 in cmd_log builtin/log.c:882 #9 0x563b7c802993 in run_builtin git.c:466 #10 0x563b7c803397 in handle_builtin git.c:721 #11 0x563b7c803b07 in run_argv git.c:788 #12 0x563b7c8048a7 in cmd_main git.c:923 #13 0x563b7ca99682 in main common-main.c:57 #14 0x7f0355e3c28f (/usr/lib/libc.so.6+0x2328f) #15 0x7f0355e3c349 in __libc_start_main (/usr/lib/libc.so.6+0x23349) #16 0x563b7c7fe0e4 in _start ../sysdeps/x86_64/start.S:115 SUMMARY: AddressSanitizer: heap-buffer-overflow /usr/src/debug/gcc/libsanitizer/sanitizer_common/sanitizer_common_interceptors.inc:725 in __interceptor_strchrnul Shadow bytes around the buggy address: 0x0c047fff8020: fa fa fd fd fa fa 00 06 fa fa 05 fa fa fa fd fd 0x0c047fff8030: fa fa 00 02 fa fa 06 fa fa fa 05 fa fa fa fd fd 0x0c047fff8040: fa fa 00 07 fa fa 03 fa fa fa fd fd fa fa 00 00 0x0c047fff8050: fa fa 00 01 fa fa fd fd fa fa 00 00 fa fa 00 01 0x0c047fff8060: fa fa 00 06 fa fa 00 06 fa fa 05 fa fa fa 05 fa =>0x0c047fff8070: fa fa 00[fa]fa fa fd fa fa fa fd fd fa fa fd fd 0x0c047fff8080: fa fa fd fd fa fa 00 00 fa fa 00 fa fa fa fd fa 0x0c047fff8090: fa fa fd fd fa fa 00 00 fa fa fa fa fa fa fa fa 0x0c047fff80a0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa 0x0c047fff80b0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa 0x0c047fff80c0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa Shadow byte legend (one shadow byte represents 8 application bytes): Addressable: 00 Partially addressable: 01 02 03 04 05 06 07 Heap left redzone: fa Freed heap region: fd Stack left redzone: f1 Stack mid redzone: f2 Stack right redzone: f3 Stack after return: f5 Stack use after scope: f8 Global redzone: f9 Global init order: f6 Poisoned by user: f7 Container overflow: fc Array cookie: ac Intra object redzone: bb ASan internal: fe Left alloca redzone: ca Right alloca redzone: cb ==10888==ABORTING Fix this bug by checking whether `end` points at the trailing NUL byte. Add a test which catches this out-of-bounds read and which demonstrates that we used to write out-of-bounds data into the formatted message. Reported-by: Markus Vervier <markus.vervier@x41-dsec.de> Original-patch-by: Markus Vervier <markus.vervier@x41-dsec.de> Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com> 09 December 2022, 05:26:21 UTC
b49f309 Patrick Steinhardt 01 December 2022, 14:46:30 UTC pretty: fix out-of-bounds read when left-flushing with stealing With the `%>>(<N>)` pretty formatter, you can ask git-log(1) et al to steal spaces. To do so we need to look ahead of the next token to see whether there are spaces there. This loop takes into account ANSI sequences that end with an `m`, and if it finds any it will skip them until it finds the first space. While doing so it does not take into account the buffer's limits though and easily does an out-of-bounds read. Add a test that hits this behaviour. While we don't have an easy way to verify this, the test causes the following failure when run with `SANITIZE=address`: ==37941==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x603000000baf at pc 0x55ba6f88e0d0 bp 0x7ffc84c50d20 sp 0x7ffc84c50d10 READ of size 1 at 0x603000000baf thread T0 #0 0x55ba6f88e0cf in format_and_pad_commit pretty.c:1712 #1 0x55ba6f88e7b4 in format_commit_item pretty.c:1801 #2 0x55ba6f9b1ae4 in strbuf_expand strbuf.c:429 #3 0x55ba6f88f020 in repo_format_commit_message pretty.c:1869 #4 0x55ba6f890ccf in pretty_print_commit pretty.c:2161 #5 0x55ba6f7884c8 in show_log log-tree.c:781 #6 0x55ba6f78b6ba in log_tree_commit log-tree.c:1117 #7 0x55ba6f40fed5 in cmd_log_walk_no_free builtin/log.c:508 #8 0x55ba6f41035b in cmd_log_walk builtin/log.c:549 #9 0x55ba6f4131a2 in cmd_log builtin/log.c:883 #10 0x55ba6f2ea993 in run_builtin git.c:466 #11 0x55ba6f2eb397 in handle_builtin git.c:721 #12 0x55ba6f2ebb07 in run_argv git.c:788 #13 0x55ba6f2ec8a7 in cmd_main git.c:923 #14 0x55ba6f581682 in main common-main.c:57 #15 0x7f2d08c3c28f (/usr/lib/libc.so.6+0x2328f) #16 0x7f2d08c3c349 in __libc_start_main (/usr/lib/libc.so.6+0x23349) #17 0x55ba6f2e60e4 in _start ../sysdeps/x86_64/start.S:115 0x603000000baf is located 1 bytes to the left of 24-byte region [0x603000000bb0,0x603000000bc8) allocated by thread T0 here: #0 0x7f2d08ebe7ea in __interceptor_realloc /usr/src/debug/gcc/libsanitizer/asan/asan_malloc_linux.cpp:85 #1 0x55ba6fa5b494 in xrealloc wrapper.c:136 #2 0x55ba6f9aefdc in strbuf_grow strbuf.c:99 #3 0x55ba6f9b0a06 in strbuf_add strbuf.c:298 #4 0x55ba6f9b1a25 in strbuf_expand strbuf.c:418 #5 0x55ba6f88f020 in repo_format_commit_message pretty.c:1869 #6 0x55ba6f890ccf in pretty_print_commit pretty.c:2161 #7 0x55ba6f7884c8 in show_log log-tree.c:781 #8 0x55ba6f78b6ba in log_tree_commit log-tree.c:1117 #9 0x55ba6f40fed5 in cmd_log_walk_no_free builtin/log.c:508 #10 0x55ba6f41035b in cmd_log_walk builtin/log.c:549 #11 0x55ba6f4131a2 in cmd_log builtin/log.c:883 #12 0x55ba6f2ea993 in run_builtin git.c:466 #13 0x55ba6f2eb397 in handle_builtin git.c:721 #14 0x55ba6f2ebb07 in run_argv git.c:788 #15 0x55ba6f2ec8a7 in cmd_main git.c:923 #16 0x55ba6f581682 in main common-main.c:57 #17 0x7f2d08c3c28f (/usr/lib/libc.so.6+0x2328f) #18 0x7f2d08c3c349 in __libc_start_main (/usr/lib/libc.so.6+0x23349) #19 0x55ba6f2e60e4 in _start ../sysdeps/x86_64/start.S:115 SUMMARY: AddressSanitizer: heap-buffer-overflow pretty.c:1712 in format_and_pad_commit Shadow bytes around the buggy address: 0x0c067fff8120: fa fa fd fd fd fa fa fa fd fd fd fa fa fa fd fd 0x0c067fff8130: fd fd fa fa fd fd fd fd fa fa fd fd fd fa fa fa 0x0c067fff8140: fd fd fd fa fa fa fd fd fd fa fa fa fd fd fd fa 0x0c067fff8150: fa fa fd fd fd fd fa fa 00 00 00 fa fa fa fd fd 0x0c067fff8160: fd fa fa fa fd fd fd fa fa fa fd fd fd fa fa fa =>0x0c067fff8170: fd fd fd fa fa[fa]00 00 00 fa fa fa 00 00 00 fa 0x0c067fff8180: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa 0x0c067fff8190: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa 0x0c067fff81a0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa 0x0c067fff81b0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa 0x0c067fff81c0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa Shadow byte legend (one shadow byte represents 8 application bytes): Addressable: 00 Partially addressable: 01 02 03 04 05 06 07 Heap left redzone: fa Freed heap region: fd Stack left redzone: f1 Stack mid redzone: f2 Stack right redzone: f3 Stack after return: f5 Stack use after scope: f8 Global redzone: f9 Global init order: f6 Poisoned by user: f7 Container overflow: fc Array cookie: ac Intra object redzone: bb ASan internal: fe Left alloca redzone: ca Right alloca redzone: cb Luckily enough, this would only cause us to copy the out-of-bounds data into the formatted commit in case we really had an ANSI sequence preceding our buffer. So this bug likely has no security consequences. Fix it regardless by not traversing past the buffer's start. Reported-by: Patrick Steinhardt <ps@pks.im> Reported-by: Eric Sesterhenn <eric.sesterhenn@x41-dsec.de> Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com> 09 December 2022, 05:26:21 UTC
81dc898 Patrick Steinhardt 01 December 2022, 14:46:25 UTC pretty: fix out-of-bounds write caused by integer overflow When using a padding specifier in the pretty format passed to git-log(1) we need to calculate the string length in several places. These string lengths are stored in `int`s though, which means that these can easily overflow when the input lengths exceeds 2GB. This can ultimately lead to an out-of-bounds write when these are used in a call to memcpy(3P): ==8340==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x7f1ec62f97fe at pc 0x7f2127e5f427 bp 0x7ffd3bd63de0 sp 0x7ffd3bd63588 WRITE of size 1 at 0x7f1ec62f97fe thread T0 #0 0x7f2127e5f426 in __interceptor_memcpy /usr/src/debug/gcc/libsanitizer/sanitizer_common/sanitizer_common_interceptors.inc:827 #1 0x5628e96aa605 in format_and_pad_commit pretty.c:1762 #2 0x5628e96aa7f4 in format_commit_item pretty.c:1801 #3 0x5628e97cdb24 in strbuf_expand strbuf.c:429 #4 0x5628e96ab060 in repo_format_commit_message pretty.c:1869 #5 0x5628e96acd0f in pretty_print_commit pretty.c:2161 #6 0x5628e95a44c8 in show_log log-tree.c:781 #7 0x5628e95a76ba in log_tree_commit log-tree.c:1117 #8 0x5628e922bed5 in cmd_log_walk_no_free builtin/log.c:508 #9 0x5628e922c35b in cmd_log_walk builtin/log.c:549 #10 0x5628e922f1a2 in cmd_log builtin/log.c:883 #11 0x5628e9106993 in run_builtin git.c:466 #12 0x5628e9107397 in handle_builtin git.c:721 #13 0x5628e9107b07 in run_argv git.c:788 #14 0x5628e91088a7 in cmd_main git.c:923 #15 0x5628e939d682 in main common-main.c:57 #16 0x7f2127c3c28f (/usr/lib/libc.so.6+0x2328f) #17 0x7f2127c3c349 in __libc_start_main (/usr/lib/libc.so.6+0x23349) #18 0x5628e91020e4 in _start ../sysdeps/x86_64/start.S:115 0x7f1ec62f97fe is located 2 bytes to the left of 4831838265-byte region [0x7f1ec62f9800,0x7f1fe62f9839) allocated by thread T0 here: #0 0x7f2127ebe7ea in __interceptor_realloc /usr/src/debug/gcc/libsanitizer/asan/asan_malloc_linux.cpp:85 #1 0x5628e98774d4 in xrealloc wrapper.c:136 #2 0x5628e97cb01c in strbuf_grow strbuf.c:99 #3 0x5628e97ccd42 in strbuf_addchars strbuf.c:327 #4 0x5628e96aa55c in format_and_pad_commit pretty.c:1761 #5 0x5628e96aa7f4 in format_commit_item pretty.c:1801 #6 0x5628e97cdb24 in strbuf_expand strbuf.c:429 #7 0x5628e96ab060 in repo_format_commit_message pretty.c:1869 #8 0x5628e96acd0f in pretty_print_commit pretty.c:2161 #9 0x5628e95a44c8 in show_log log-tree.c:781 #10 0x5628e95a76ba in log_tree_commit log-tree.c:1117 #11 0x5628e922bed5 in cmd_log_walk_no_free builtin/log.c:508 #12 0x5628e922c35b in cmd_log_walk builtin/log.c:549 #13 0x5628e922f1a2 in cmd_log builtin/log.c:883 #14 0x5628e9106993 in run_builtin git.c:466 #15 0x5628e9107397 in handle_builtin git.c:721 #16 0x5628e9107b07 in run_argv git.c:788 #17 0x5628e91088a7 in cmd_main git.c:923 #18 0x5628e939d682 in main common-main.c:57 #19 0x7f2127c3c28f (/usr/lib/libc.so.6+0x2328f) #20 0x7f2127c3c349 in __libc_start_main (/usr/lib/libc.so.6+0x23349) #21 0x5628e91020e4 in _start ../sysdeps/x86_64/start.S:115 SUMMARY: AddressSanitizer: heap-buffer-overflow /usr/src/debug/gcc/libsanitizer/sanitizer_common/sanitizer_common_interceptors.inc:827 in __interceptor_memcpy Shadow bytes around the buggy address: 0x0fe458c572a0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa 0x0fe458c572b0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa 0x0fe458c572c0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa 0x0fe458c572d0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa 0x0fe458c572e0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa =>0x0fe458c572f0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa[fa] 0x0fe458c57300: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0x0fe458c57310: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0x0fe458c57320: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0x0fe458c57330: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0x0fe458c57340: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 Shadow byte legend (one shadow byte represents 8 application bytes): Addressable: 00 Partially addressable: 01 02 03 04 05 06 07 Heap left redzone: fa Freed heap region: fd Stack left redzone: f1 Stack mid redzone: f2 Stack right redzone: f3 Stack after return: f5 Stack use after scope: f8 Global redzone: f9 Global init order: f6 Poisoned by user: f7 Container overflow: fc Array cookie: ac Intra object redzone: bb ASan internal: fe Left alloca redzone: ca Right alloca redzone: cb ==8340==ABORTING The pretty format can also be used in `git archive` operations via the `export-subst` attribute. So this is what in our opinion makes this a critical issue in the context of Git forges which allow to download an archive of user supplied Git repositories. Fix this vulnerability by using `size_t` instead of `int` to track the string lengths. Add tests which detect this vulnerability when Git is compiled with the address sanitizer. Reported-by: Joern Schneeweisz <jschneeweisz@gitlab.com> Original-patch-by: Joern Schneeweisz <jschneeweisz@gitlab.com> Modified-by: Taylor Blau <me@ttalorr.com> Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com> 09 December 2022, 05:26:21 UTC
a244dc5 Carlo Marcelo Arenas Belón 02 November 2021, 15:46:06 UTC test-lib: add prerequisite for 64-bit platforms Allow tests that assume a 64-bit `size_t` to be skipped in 32-bit platforms and regardless of the size of `long`. This imitates the `LONG_IS_64BIT` prerequisite. Signed-off-by: Carlo Marcelo Arenas Belón <carenas@gmail.com> Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com> 09 December 2022, 05:26:04 UTC
3c50032 Patrick Steinhardt 01 December 2022, 14:45:53 UTC attr: ignore overly large gitattributes files Similar as with the preceding commit, start ignoring gitattributes files that are overly large to protect us against out-of-bounds reads and writes caused by integer overflows. Unfortunately, we cannot just define "overly large" in terms of any preexisting limits in the codebase. Instead, we choose a very conservative limit of 100MB. This is plenty of room for specifying gitattributes, and incidentally it is also the limit for blob sizes for GitHub. While we don't want GitHub to dictate limits here, it is still sensible to use this fact for an informed decision given that it is hosting a huge set of repositories. Furthermore, over at GitLab we scanned a subset of repositories for their root-level attribute files. We found that 80% of them have a gitattributes file smaller than 100kB, 99.99% have one smaller than 1MB, and only a single repository had one that was almost 3MB in size. So enforcing a limit of 100MB seems to give us ample of headroom. With this limit in place we can be reasonably sure that there is no easy way to exploit the gitattributes file via integer overflows anymore. Furthermore, it protects us against resource exhaustion caused by allocating the in-memory data structures required to represent the parsed attributes. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com> 05 December 2022, 06:50:03 UTC
dfa6b32 Patrick Steinhardt 01 December 2022, 14:45:48 UTC attr: ignore attribute lines exceeding 2048 bytes There are two different code paths to read gitattributes: once via a file, and once via the index. These two paths used to behave differently because when reading attributes from a file, we used fgets(3P) with a buffer size of 2kB. Consequentially, we silently truncate line lengths when lines are longer than that and will then parse the remainder of the line as a new pattern. It goes without saying that this is entirely unexpected, but it's even worse that the behaviour depends on how the gitattributes are parsed. While this is simply wrong, the silent truncation saves us with the recently discovered vulnerabilities that can cause out-of-bound writes or reads with unreasonably long lines due to integer overflows. As the common path is to read gitattributes via the worktree file instead of via the index, we can assume that any gitattributes file that had lines longer than that is already broken anyway. So instead of lifting the limit here, we can double down on it to fix the vulnerabilities. Introduce an explicit line length limit of 2kB that is shared across all paths that read attributes and ignore any line that hits this limit while printing a warning. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com> 05 December 2022, 06:33:07 UTC
d74b1fd Patrick Steinhardt 01 December 2022, 14:45:44 UTC attr: fix silently splitting up lines longer than 2048 bytes When reading attributes from a file we use fgets(3P) with a buffer size of 2048 bytes. This means that as soon as a line exceeds the buffer size we split it up into multiple parts and parse each of them as a separate pattern line. This is of course not what the user intended, and even worse the behaviour is inconsistent with how we read attributes from the index. Fix this bug by converting the code to use `strbuf_getline()` instead. This will indeed read in the whole line, which may theoretically lead to an out-of-memory situation when the gitattributes file is huge. We're about to reject any gitattributes files larger than 100MB in the next commit though, which makes this less of a concern. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com> 05 December 2022, 06:29:30 UTC
a60a66e Patrick Steinhardt 01 December 2022, 14:45:40 UTC attr: harden allocation against integer overflows When parsing an attributes line, we need to allocate an array that holds all attributes specified for the given file pattern. The calculation to determine the number of bytes that need to be allocated was prone to an overflow though when there was an unreasonable amount of attributes. Harden the allocation by instead using the `st_` helper functions that cause us to die when we hit an integer overflow. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com> 05 December 2022, 06:14:16 UTC
e1e12e9 Patrick Steinhardt 01 December 2022, 14:45:36 UTC attr: fix integer overflow with more than INT_MAX macros Attributes have a field that tracks the position in the `all_attrs` array they're stored inside. This field gets set via `hashmap_get_size` when adding the attribute to the global map of attributes. But while the field is of type `int`, the value returned by `hashmap_get_size` is an `unsigned int`. It can thus happen that the value overflows, where we would now dereference teh `all_attrs` array at an out-of-bounds value. We do have a sanity check for this overflow via an assert that verifies the index matches the new hashmap's size. But asserts are not a proper mechanism to detect against any such overflows as they may not in fact be compiled into production code. Fix this by using an `unsigned int` to track the index and convert the assert to a call `die()`. Reported-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com> 05 December 2022, 06:14:16 UTC
447ac90 Patrick Steinhardt 01 December 2022, 14:45:31 UTC attr: fix out-of-bounds read with unreasonable amount of patterns The `struct attr_stack` tracks the stack of all patterns together with their attributes. When parsing a gitattributes file that has more than 2^31 such patterns though we may trigger multiple out-of-bounds reads on 64 bit platforms. This is because while the `num_matches` variable is an unsigned integer, we always use a signed integer to iterate over them. I have not been able to reproduce this issue due to memory constraints on my systems. But despite the out-of-bounds reads, the worst thing that can seemingly happen is to call free(3P) with a garbage pointer when calling `attr_stack_free()`. Fix this bug by using unsigned integers to iterate over the array. While this makes the iteration somewhat awkward when iterating in reverse, it is at least better than knowingly running into an out-of-bounds read. While at it, convert the call to `ALLOC_GROW` to use `ALLOC_GROW_BY` instead. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com> 05 December 2022, 06:14:16 UTC
34ace8b Patrick Steinhardt 01 December 2022, 14:45:27 UTC attr: fix out-of-bounds write when parsing huge number of attributes It is possible to trigger an integer overflow when parsing attribute names when there are more than 2^31 of them for a single pattern. This can either lead to us dying due to trying to request too many bytes: blob=$(perl -e 'print "f" . " a=" x 2147483649' | git hash-object -w --stdin) git update-index --add --cacheinfo 100644,$blob,.gitattributes git attr-check --all file ================================================================= ==1022==ERROR: AddressSanitizer: requested allocation size 0xfffffff800000032 (0xfffffff800001038 after adjustments for alignment, red zones etc.) exceeds maximum supported size of 0x10000000000 (thread T0) #0 0x7fd3efabf411 in __interceptor_calloc /usr/src/debug/gcc/libsanitizer/asan/asan_malloc_linux.cpp:77 #1 0x5563a0a1e3d3 in xcalloc wrapper.c:150 #2 0x5563a058d005 in parse_attr_line attr.c:384 #3 0x5563a058e661 in handle_attr_line attr.c:660 #4 0x5563a058eddb in read_attr_from_index attr.c:769 #5 0x5563a058ef12 in read_attr attr.c:797 #6 0x5563a058f24c in bootstrap_attr_stack attr.c:867 #7 0x5563a058f4a3 in prepare_attr_stack attr.c:902 #8 0x5563a05905da in collect_some_attrs attr.c:1097 #9 0x5563a059093d in git_all_attrs attr.c:1128 #10 0x5563a02f636e in check_attr builtin/check-attr.c:67 #11 0x5563a02f6c12 in cmd_check_attr builtin/check-attr.c:183 #12 0x5563a02aa993 in run_builtin git.c:466 #13 0x5563a02ab397 in handle_builtin git.c:721 #14 0x5563a02abb2b in run_argv git.c:788 #15 0x5563a02ac991 in cmd_main git.c:926 #16 0x5563a05432bd in main common-main.c:57 #17 0x7fd3ef82228f (/usr/lib/libc.so.6+0x2328f) ==1022==HINT: if you don't care about these errors you may set allocator_may_return_null=1 SUMMARY: AddressSanitizer: allocation-size-too-big /usr/src/debug/gcc/libsanitizer/asan/asan_malloc_linux.cpp:77 in __interceptor_calloc ==1022==ABORTING Or, much worse, it can lead to an out-of-bounds write because we underallocate and then memcpy(3P) into an array: perl -e ' print "A " . "\rh="x2000000000; print "\rh="x2000000000; print "\rh="x294967294 . "\n" ' >.gitattributes git add .gitattributes git commit -am "evil attributes" $ git clone --quiet /path/to/repo ================================================================= ==15062==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x602000002550 at pc 0x5555559884d5 bp 0x7fffffffbc60 sp 0x7fffffffbc58 WRITE of size 8 at 0x602000002550 thread T0 #0 0x5555559884d4 in parse_attr_line attr.c:393 #1 0x5555559884d4 in handle_attr_line attr.c:660 #2 0x555555988902 in read_attr_from_index attr.c:784 #3 0x555555988902 in read_attr_from_index attr.c:747 #4 0x555555988a1d in read_attr attr.c:800 #5 0x555555989b0c in bootstrap_attr_stack attr.c:882 #6 0x555555989b0c in prepare_attr_stack attr.c:917 #7 0x555555989b0c in collect_some_attrs attr.c:1112 #8 0x55555598b141 in git_check_attr attr.c:1126 #9 0x555555a13004 in convert_attrs convert.c:1311 #10 0x555555a95e04 in checkout_entry_ca entry.c:553 #11 0x555555d58bf6 in checkout_entry entry.h:42 #12 0x555555d58bf6 in check_updates unpack-trees.c:480 #13 0x555555d5eb55 in unpack_trees unpack-trees.c:2040 #14 0x555555785ab7 in checkout builtin/clone.c:724 #15 0x555555785ab7 in cmd_clone builtin/clone.c:1384 #16 0x55555572443c in run_builtin git.c:466 #17 0x55555572443c in handle_builtin git.c:721 #18 0x555555727872 in run_argv git.c:788 #19 0x555555727872 in cmd_main git.c:926 #20 0x555555721fa0 in main common-main.c:57 #21 0x7ffff73f1d09 in __libc_start_main ../csu/libc-start.c:308 #22 0x555555723f39 in _start (git+0x1cff39) 0x602000002552 is located 0 bytes to the right of 2-byte region [0x602000002550,0x602000002552) allocated by thread T0 here: #0 0x7ffff768c037 in __interceptor_calloc ../../../../src/libsanitizer/asan/asan_malloc_linux.cpp:154 #1 0x555555d7fff7 in xcalloc wrapper.c:150 #2 0x55555598815f in parse_attr_line attr.c:384 #3 0x55555598815f in handle_attr_line attr.c:660 #4 0x555555988902 in read_attr_from_index attr.c:784 #5 0x555555988902 in read_attr_from_index attr.c:747 #6 0x555555988a1d in read_attr attr.c:800 #7 0x555555989b0c in bootstrap_attr_stack attr.c:882 #8 0x555555989b0c in prepare_attr_stack attr.c:917 #9 0x555555989b0c in collect_some_attrs attr.c:1112 #10 0x55555598b141 in git_check_attr attr.c:1126 #11 0x555555a13004 in convert_attrs convert.c:1311 #12 0x555555a95e04 in checkout_entry_ca entry.c:553 #13 0x555555d58bf6 in checkout_entry entry.h:42 #14 0x555555d58bf6 in check_updates unpack-trees.c:480 #15 0x555555d5eb55 in unpack_trees unpack-trees.c:2040 #16 0x555555785ab7 in checkout builtin/clone.c:724 #17 0x555555785ab7 in cmd_clone builtin/clone.c:1384 #18 0x55555572443c in run_builtin git.c:466 #19 0x55555572443c in handle_builtin git.c:721 #20 0x555555727872 in run_argv git.c:788 #21 0x555555727872 in cmd_main git.c:926 #22 0x555555721fa0 in main common-main.c:57 #23 0x7ffff73f1d09 in __libc_start_main ../csu/libc-start.c:308 SUMMARY: AddressSanitizer: heap-buffer-overflow attr.c:393 in parse_attr_line Shadow bytes around the buggy address: 0x0c047fff8450: fa fa 00 02 fa fa 00 07 fa fa fd fd fa fa 00 00 0x0c047fff8460: fa fa 02 fa fa fa fd fd fa fa 00 06 fa fa 05 fa 0x0c047fff8470: fa fa fd fd fa fa 00 02 fa fa 06 fa fa fa 05 fa 0x0c047fff8480: fa fa 07 fa fa fa fd fd fa fa 00 01 fa fa 00 02 0x0c047fff8490: fa fa 00 03 fa fa 00 fa fa fa 00 01 fa fa 00 03 =>0x0c047fff84a0: fa fa 00 01 fa fa 00 02 fa fa[02]fa fa fa fa fa 0x0c047fff84b0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa 0x0c047fff84c0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa 0x0c047fff84d0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa 0x0c047fff84e0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa 0x0c047fff84f0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa Shadow byte legend (one shadow byte represents 8 application bytes): Addressable: 00 Partially addressable: 01 02 03 04 05 06 07 Heap left redzone: fa Freed heap region: fd Stack left redzone: f1 Stack mid redzone: f2 Stack right redzone: f3 Stack after return: f5 Stack use after scope: f8 Global redzone: f9 Global init order: f6 Poisoned by user: f7 Container overflow: fc Array cookie: ac Intra object redzone: bb ASan internal: fe Left alloca redzone: ca Right alloca redzone: cb Shadow gap: cc ==15062==ABORTING Fix this bug by using `size_t` instead to count the number of attributes so that this value cannot reasonably overflow without running out of memory before already. Reported-by: Markus Vervier <markus.vervier@x41-dsec.de> Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com> 05 December 2022, 06:14:16 UTC
2455720 Patrick Steinhardt 01 December 2022, 14:45:23 UTC attr: fix integer overflow when parsing huge attribute names It is possible to trigger an integer overflow when parsing attribute names that are longer than 2^31 bytes because we assign the result of strlen(3P) to an `int` instead of to a `size_t`. This can lead to an abort in vsnprintf(3P) with the following reproducer: blob=$(perl -e 'print "A " . "B"x2147483648 . "\n"' | git hash-object -w --stdin) git update-index --add --cacheinfo 100644,$blob,.gitattributes git check-attr --all path BUG: strbuf.c:400: your vsnprintf is broken (returned -1) But furthermore, assuming that the attribute name is even longer than that, it can cause us to silently truncate the attribute and thus lead to wrong results. Fix this integer overflow by using a `size_t` instead. This fixes the silent truncation of attribute names, but it only partially fixes the BUG we hit: even though the initial BUG is fixed, we can still hit a BUG when parsing invalid attribute lines via `report_invalid_attr()`. This is due to an underlying design issue in vsnprintf(3P) which only knows to return an `int`, and thus it may always overflow with large inputs. This issue is benign though: the worst that can happen is that the error message is misreported to be either truncated or too long, but due to the buffer being NUL terminated we wouldn't ever do an out-of-bounds read here. Reported-by: Markus Vervier <markus.vervier@x41-dsec.de> Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com> 05 December 2022, 06:14:16 UTC
8d0d48c Patrick Steinhardt 01 December 2022, 14:45:19 UTC attr: fix out-of-bounds read with huge attribute names There is an out-of-bounds read possible when parsing gitattributes that have an attribute that is 2^31+1 bytes long. This is caused due to an integer overflow when we assign the result of strlen(3P) to an `int`, where we use the wrapped-around value in a subsequent call to memcpy(3P). The following code reproduces the issue: blob=$(perl -e 'print "a" x 2147483649 . " attr"' | git hash-object -w --stdin) git update-index --add --cacheinfo 100644,$blob,.gitattributes git check-attr --all file AddressSanitizer:DEADLYSIGNAL ================================================================= ==8451==ERROR: AddressSanitizer: SEGV on unknown address 0x7f93efa00800 (pc 0x7f94f1f8f082 bp 0x7ffddb59b3a0 sp 0x7ffddb59ab28 T0) ==8451==The signal is caused by a READ memory access. #0 0x7f94f1f8f082 (/usr/lib/libc.so.6+0x176082) #1 0x7f94f2047d9c in __interceptor_strspn /usr/src/debug/gcc/libsanitizer/sanitizer_common/sanitizer_common_interceptors.inc:752 #2 0x560e190f7f26 in parse_attr_line attr.c:375 #3 0x560e190f9663 in handle_attr_line attr.c:660 #4 0x560e190f9ddd in read_attr_from_index attr.c:769 #5 0x560e190f9f14 in read_attr attr.c:797 #6 0x560e190fa24e in bootstrap_attr_stack attr.c:867 #7 0x560e190fa4a5 in prepare_attr_stack attr.c:902 #8 0x560e190fb5dc in collect_some_attrs attr.c:1097 #9 0x560e190fb93f in git_all_attrs attr.c:1128 #10 0x560e18e6136e in check_attr builtin/check-attr.c:67 #11 0x560e18e61c12 in cmd_check_attr builtin/check-attr.c:183 #12 0x560e18e15993 in run_builtin git.c:466 #13 0x560e18e16397 in handle_builtin git.c:721 #14 0x560e18e16b2b in run_argv git.c:788 #15 0x560e18e17991 in cmd_main git.c:926 #16 0x560e190ae2bd in main common-main.c:57 #17 0x7f94f1e3c28f (/usr/lib/libc.so.6+0x2328f) #18 0x7f94f1e3c349 in __libc_start_main (/usr/lib/libc.so.6+0x23349) #19 0x560e18e110e4 in _start ../sysdeps/x86_64/start.S:115 AddressSanitizer can not provide additional info. SUMMARY: AddressSanitizer: SEGV (/usr/lib/libc.so.6+0x176082) ==8451==ABORTING Fix this bug by converting the variable to a `size_t` instead. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com> 05 December 2022, 06:14:16 UTC
eb22e7d Patrick Steinhardt 01 December 2022, 14:45:15 UTC attr: fix overflow when upserting attribute with overly long name The function `git_attr_internal()` is called to upsert attributes into the global map. And while all callers pass a `size_t`, the function itself accepts an `int` as the attribute name's length. This can lead to an integer overflow in case the attribute name is longer than `INT_MAX`. Now this overflow seems harmless as the first thing we do is to call `attr_name_valid()`, and that function only succeeds in case all chars in the range of `namelen` match a certain small set of chars. We thus can't do an out-of-bounds read as NUL is not part of that set and all strings passed to this function are NUL-terminated. And furthermore, we wouldn't ever read past the current attribute name anyway due to the same reason. And if validation fails we will return early. On the other hand it feels fragile to rely on this behaviour, even more so given that we pass `namelen` to `FLEX_ALLOC_MEM()`. So let's instead just do the correct thing here and accept a `size_t` as line length. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com> 05 December 2022, 06:14:16 UTC
fcdaa21 Taylor Blau 30 September 2022, 21:37:57 UTC Git 2.36.3 Signed-off-by: Taylor Blau <me@ttaylorr.com> 06 October 2022, 21:45:10 UTC
58612f8 Taylor Blau 06 October 2022, 21:44:44 UTC Sync with 2.35.5 Signed-off-by: Taylor Blau <me@ttaylorr.com> 06 October 2022, 21:44:44 UTC
868154b Taylor Blau 30 September 2022, 21:25:26 UTC Git 2.35.5 Signed-off-by: Taylor Blau <me@ttaylorr.com> 06 October 2022, 21:44:02 UTC
ac8a1db Taylor Blau 06 October 2022, 21:43:37 UTC Sync with 2.34.5 Signed-off-by: Taylor Blau <me@ttaylorr.com> 06 October 2022, 21:43:37 UTC
be85cfc Taylor Blau 30 September 2022, 21:22:02 UTC Git 2.34.5 Signed-off-by: Taylor Blau <me@ttaylorr.com> 06 October 2022, 21:43:08 UTC
478a426 Taylor Blau 06 October 2022, 21:42:55 UTC Sync with 2.33.5 Signed-off-by: Taylor Blau <me@ttaylorr.com> 06 October 2022, 21:42:55 UTC
7800e1d Taylor Blau 30 September 2022, 21:04:26 UTC Git 2.33.5 Signed-off-by: Taylor Blau <me@ttaylorr.com> 06 October 2022, 21:42:27 UTC
3957f3c Taylor Blau 06 October 2022, 21:42:02 UTC Sync with 2.32.4 Signed-off-by: Taylor Blau <me@ttaylorr.com> 06 October 2022, 21:42:02 UTC
af778cd Taylor Blau 30 September 2022, 21:00:58 UTC Git 2.32.4 Signed-off-by: Taylor Blau <me@ttaylorr.com> 06 October 2022, 21:41:15 UTC
9cbd282 Taylor Blau 06 October 2022, 21:40:44 UTC Sync with 2.31.5 Signed-off-by: Taylor Blau <me@ttaylorr.com> 06 October 2022, 21:40:44 UTC
ecf9b4a Taylor Blau 30 September 2022, 20:56:02 UTC Git 2.31.5 Signed-off-by: Taylor Blau <me@ttaylorr.com> 06 October 2022, 21:39:26 UTC
1225129 Taylor Blau 06 October 2022, 21:39:15 UTC Sync with 2.30.6 Signed-off-by: Taylor Blau <me@ttaylorr.com> 06 October 2022, 21:39:15 UTC
abd4d67 Taylor Blau 30 September 2022, 20:32:10 UTC Git 2.30.6 Signed-off-by: Taylor Blau <me@ttaylorr.com> 06 October 2022, 21:38:16 UTC
8a7bfa0 Taylor Blau 30 September 2022, 20:47:00 UTC t7814: prepare for changing protocol.file.allow Explicitly cloning over the "file://" protocol in t7814 in preparation for merging a security release which will change the default value of this configuration to be "user". Signed-off-by: Taylor Blau <me@ttaylorr.com> 01 October 2022, 04:31:40 UTC
59f2f80 Taylor Blau 30 September 2022, 20:47:00 UTC t5537: prepare for changing protocol.file.allow Explicitly cloning over the "file://" protocol in t5537 in preparation for merging a security release which will change the default value of this configuration to be "user". Signed-off-by: Taylor Blau <me@ttaylorr.com> 01 October 2022, 04:31:36 UTC
c193e6b Taylor Blau 30 September 2022, 20:47:00 UTC t5516: prepare for changing protocol.file.allow Explicitly cloning over the "file://" protocol in t5516 in preparation for merging a security release which will change the default value of this configuration to be "user". Signed-off-by: Taylor Blau <me@ttaylorr.com> 01 October 2022, 04:31:34 UTC
e175fb5 Taylor Blau 30 September 2022, 20:47:00 UTC t3207: prepare for changing protocol.file.allow Explicitly cloning over the "file://" protocol in t3207 in preparation for merging a security release which will change the default value of this configuration to be "user". Signed-off-by: Taylor Blau <me@ttaylorr.com> 01 October 2022, 04:31:31 UTC
ef374dd Taylor Blau 30 September 2022, 20:48:56 UTC t2080: prepare for changing protocol.file.allow Explicitly cloning over the "file://" protocol in t1092 in preparation for merging a security release which will change the default value of this configuration to be "user". Signed-off-by: Taylor Blau <me@ttaylorr.com> 01 October 2022, 04:30:45 UTC
092d3a2 Taylor Blau 30 September 2022, 20:47:00 UTC t1092: prepare for changing protocol.file.allow Explicitly cloning over the "file://" protocol in t1092 in preparation for merging a security release which will change the default value of this configuration to be "user". Signed-off-by: Taylor Blau <me@ttaylorr.com> 01 October 2022, 04:30:43 UTC
067aa8f Taylor Blau 30 September 2022, 20:48:56 UTC t2080: prepare for changing protocol.file.allow Explicitly cloning over the "file://" protocol in t1092 in preparation for merging a security release which will change the default value of this configuration to be "user". Signed-off-by: Taylor Blau <me@ttaylorr.com> 01 October 2022, 04:27:18 UTC
4a7dab5 Taylor Blau 30 September 2022, 20:47:00 UTC t1092: prepare for changing protocol.file.allow Explicitly cloning over the "file://" protocol in t1092 in preparation for merging a security release which will change the default value of this configuration to be "user". Signed-off-by: Taylor Blau <me@ttaylorr.com> 01 October 2022, 04:27:14 UTC
0ca6ead Kevin Backhouse 28 September 2022, 22:53:32 UTC alias.c: reject too-long cmdline strings in split_cmdline() This function improperly uses an int to represent the number of entries in the resulting argument array. This allows a malicious actor to intentionally overflow the return value, leading to arbitrary heap writes. Because the resulting argv array is typically passed to execv(), it may be possible to leverage this attack to gain remote code execution on a victim machine. This was almost certainly the case for certain configurations of git-shell until the previous commit limited the size of input it would accept. Other calls to split_cmdline() are typically limited by the size of argv the OS is willing to hand us, so are similarly protected. So this is not strictly fixing a known vulnerability, but is a hardening of the function that is worth doing to protect against possible unknown vulnerabilities. One approach to fixing this would be modifying the signature of `split_cmdline()` to look something like: int split_cmdline(char *cmdline, const char ***argv, size_t *argc); Where the return value of `split_cmdline()` is negative for errors, and zero otherwise. If non-NULL, the `*argc` pointer is modified to contain the size of the `**argv` array. But this implies an absurdly large `argv` array, which more than likely larger than the system's argument limit. So even if split_cmdline() allowed this, it would fail immediately afterwards when we called execv(). So instead of converting all of `split_cmdline()`'s callers to work with `size_t` types in this patch, instead pursue the minimal fix here to prevent ever returning an array with more than INT_MAX entries in it. Signed-off-by: Kevin Backhouse <kevinbackhouse@github.com> Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Taylor Blau <me@ttaylorr.com> 01 October 2022, 04:23:38 UTC
71ad7fe Jeff King 28 September 2022, 22:52:48 UTC shell: limit size of interactive commands When git-shell is run in interactive mode (which must be enabled by creating $HOME/git-shell-commands), it reads commands from stdin, one per line, and executes them. We read the commands with git_read_line_interactively(), which uses a strbuf under the hood. That means we'll accept an input of arbitrary size (limited only by how much heap we can allocate). That creates two problems: - the rest of the code is not prepared to handle large inputs. The most serious issue here is that split_cmdline() uses "int" for most of its types, which can lead to integer overflow and out-of-bounds array reads and writes. But even with that fixed, we assume that we can feed the command name to snprintf() (via xstrfmt()), which is stuck for historical reasons using "int", and causes it to fail (and even trigger a BUG() call). - since the point of git-shell is to take input from untrusted or semi-trusted clients, it's a mild denial-of-service. We'll allocate as many bytes as the client sends us (actually twice as many, since we immediately duplicate the buffer). We can fix both by just limiting the amount of per-command input we're willing to receive. We should also fix split_cmdline(), of course, which is an accident waiting to happen, but that can come on top. Most calls to split_cmdline(), including the other one in git-shell, are OK because they are reading from an OS-provided argv, which is limited in practice. This patch should eliminate the immediate vulnerabilities. I picked 4MB as an arbitrary limit. It's big enough that nobody should ever run into it in practice (since the point is to run the commands via exec, we're subject to OS limits which are typically much lower). But it's small enough that allocating it isn't that big a deal. The code is mostly just swapping out fgets() for the strbuf call, but we have to add a few niceties like flushing and trimming line endings. We could simplify things further by putting the buffer on the stack, but 4MB is probably a bit much there. Note that we'll _always_ allocate 4MB, which for normal, non-malicious requests is more than we would before this patch. But on the other hand, other git programs are happy to use 96MB for a delta cache. And since we'd never touch most of those pages, on a lazy-allocating OS like Linux they won't even get allocated to actual RAM. The ideal would be a version of strbuf_getline() that accepted a maximum value. But for a minimal vulnerability fix, let's keep things localized and simple. We can always refactor further on top. The included test fails in an obvious way with ASan or UBSan (which notice the integer overflow and out-of-bounds reads). Without them, it fails in a less obvious way: we may segfault, or we may try to xstrfmt() a long string, leading to a BUG(). Either way, it fails reliably before this patch, and passes with it. Note that we don't need an EXPENSIVE prereq on it. It does take 10-15s to fail before this patch, but with the new limit, we fail almost immediately (and the perl process generating 2GB of data exits via SIGPIPE). Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Taylor Blau <me@ttaylorr.com> 01 October 2022, 04:23:38 UTC
32696a4 Jeff King 28 September 2022, 22:50:36 UTC shell: add basic tests We have no tests of even basic functionality of git-shell. Let's add a couple of obvious ones. This will serve as a framework for adding tests for new things we fix, as well as making sure we don't screw anything up too badly while doing so. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Taylor Blau <me@ttaylorr.com> 01 October 2022, 04:23:38 UTC
a1d4f67 Taylor Blau 29 July 2022, 19:22:13 UTC transport: make `protocol.file.allow` be "user" by default An earlier patch discussed and fixed a scenario where Git could be used as a vector to exfiltrate sensitive data through a Docker container when a potential victim clones a suspicious repository with local submodules that contain symlinks. That security hole has since been plugged, but a similar one still exists. Instead of convincing a would-be victim to clone an embedded submodule via the "file" protocol, an attacker could convince an individual to clone a repository that has a submodule pointing to a valid path on the victim's filesystem. For example, if an individual (with username "foo") has their home directory ("/home/foo") stored as a Git repository, then an attacker could exfiltrate data by convincing a victim to clone a malicious repository containing a submodule pointing at "/home/foo/.git" with `--recurse-submodules`. Doing so would expose any sensitive contents in stored in "/home/foo" tracked in Git. For systems (such as Docker) that consider everything outside of the immediate top-level working directory containing a Dockerfile as inaccessible to the container (with the exception of volume mounts, and so on), this is a violation of trust by exposing unexpected contents in the working copy. To mitigate the likelihood of this kind of attack, adjust the "file://" protocol's default policy to be "user" to prevent commands that execute without user input (including recursive submodule initialization) from taking place by default. Suggested-by: Jeff King <peff@peff.net> Signed-off-by: Taylor Blau <me@ttaylorr.com> 01 October 2022, 04:23:38 UTC
f4a32a5 Taylor Blau 29 July 2022, 19:21:53 UTC t/t9NNN: allow local submodules To prepare for the default value of `protocol.file.allow` to change to "user", ensure tests that rely on local submodules can initialize them over the file protocol. Tests that interact with submodules a handful of times use `test_config_global`. Signed-off-by: Taylor Blau <me@ttaylorr.com> 01 October 2022, 04:23:38 UTC
0d3beb7 Taylor Blau 29 July 2022, 19:21:40 UTC t/t7NNN: allow local submodules To prepare for the default value of `protocol.file.allow` to change to "user", ensure tests that rely on local submodules can initialize them over the file protocol. Tests that only need to interact with submodules in a limited capacity have individual Git commands annotated with the appropriate configuration via `-c`. Tests that interact with submodules a handful of times use `test_config_global` instead. Test scripts that rely on submodules throughout use a `git config --global` during a setup test towards the beginning of the script. Signed-off-by: Taylor Blau <me@ttaylorr.com> 01 October 2022, 04:23:38 UTC
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