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2018-05-21verify_path: disallow symlinks in .gitmodulesLibravatar Jeff King4-15/+37
There are a few reasons it's not a good idea to make .gitmodules a symlink, including: 1. It won't be portable to systems without symlinks. 2. It may behave inconsistently, since Git may look at this file in the index or a tree without bothering to resolve any symbolic links. We don't do this _yet_, but the config infrastructure is there and it's planned for the future. With some clever code, we could make (2) work. And some people may not care about (1) if they only work on one platform. But there are a few security reasons to simply disallow it: a. A symlinked .gitmodules file may circumvent any fsck checks of the content. b. Git may read and write from the on-disk file without sanity checking the symlink target. So for example, if you link ".gitmodules" to "../oops" and run "git submodule add", we'll write to the file "oops" outside the repository. Again, both of those are problems that _could_ be solved with sufficient code, but given the complications in (1) and (2), we're better off just outlawing it explicitly. Note the slightly tricky call to verify_path() in update-index's update_one(). There we may not have a mode if we're not updating from the filesystem (e.g., we might just be removing the file). Passing "0" as the mode there works fine; since it's not a symlink, we'll just skip the extra checks. Signed-off-by: Jeff King <peff@peff.net>
2018-05-21update-index: stat updated files earlierLibravatar Jeff King1-8/+17
In the update_one(), we check verify_path() on the proposed path before doing anything else. In preparation for having verify_path() look at the file mode, let's stat the file earlier, so we can check the mode accurately. This is made a bit trickier by the fact that this function only does an lstat in a few code paths (the ones that flow down through process_path()). So we can speculatively do the lstat() here and pass the results down, and just use a dummy mode for cases where we won't actually be updating the index from the filesystem. Signed-off-by: Jeff King <peff@peff.net>
2018-05-21verify_dotfile: mention case-insensitivity in commentLibravatar Jeff King1-1/+4
We're more restrictive than we need to be in matching ".GIT" on case-sensitive filesystems; let's make a note that this is intentional. Signed-off-by: Jeff King <peff@peff.net>
2018-05-21verify_path: drop clever fallthroughLibravatar Jeff King1-4/+4
We check ".git" and ".." in the same switch statement, and fall through the cases to share the end-of-component check. While this saves us a line or two, it makes modifying the function much harder. Let's just write it out. Signed-off-by: Jeff King <peff@peff.net>
2018-05-21skip_prefix: add case-insensitive variantLibravatar Jeff King1-0/+17
We have the convenient skip_prefix() helper, but if you want to do case-insensitive matching, you're stuck doing it by hand. We could add an extra parameter to the function to let callers ask for this, but the function is small and somewhat performance-critical. Let's just re-implement it for the case-insensitive version. Signed-off-by: Jeff King <peff@peff.net>
2018-05-21is_{hfs,ntfs}_dotgitmodules: add testsLibravatar Johannes Schindelin2-0/+106
This tests primarily for NTFS issues, but also adds one example of an HFS+ issue. Thanks go to Congyi Wu for coming up with the list of examples where NTFS would possibly equate the filename with `.gitmodules`. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Jeff King <peff@peff.net>
2018-05-21is_ntfs_dotgit: match other .git filesLibravatar Johannes Schindelin2-1/+93
When we started to catch NTFS short names that clash with .git, we only looked for GIT~1. This is sufficient because we only ever clone into an empty directory, so .git is guaranteed to be the first subdirectory or file in that directory. However, even with a fresh clone, .gitmodules is *not* necessarily the first file to be written that would want the NTFS short name GITMOD~1: a malicious repository can add .gitmodul0000 and friends, which sorts before `.gitmodules` and is therefore checked out *first*. For that reason, we have to test not only for ~1 short names, but for others, too. It's hard to just adapt the existing checks in is_ntfs_dotgit(): since Windows 2000 (i.e., in all Windows versions still supported by Git), NTFS short names are only generated in the <prefix>~<number> form up to number 4. After that, a *different* prefix is used, calculated from the long file name using an undocumented, but stable algorithm. For example, the short name of .gitmodules would be GITMOD~1, but if it is taken, and all of ~2, ~3 and ~4 are taken, too, the short name GI7EBA~1 will be used. From there, collisions are handled by incrementing the number, shortening the prefix as needed (until ~9999999 is reached, in which case NTFS will not allow the file to be created). We'd also want to handle .gitignore and .gitattributes, which suffer from a similar problem, using the fall-back short names GI250A~1 and GI7D29~1, respectively. To accommodate for that, we could reimplement the hashing algorithm, but it is just safer and simpler to provide the known prefixes. This algorithm has been reverse-engineered and described at https://usn.pw/blog/gen/2015/06/09/filenames/, which is defunct but still available via https://web.archive.org/. These can be recomputed by running the following Perl script: -- snip -- use warnings; use strict; sub compute_short_name_hash ($) { my $checksum = 0; foreach (split('', $_[0])) { $checksum = ($checksum * 0x25 + ord($_)) & 0xffff; } $checksum = ($checksum * 314159269) & 0xffffffff; $checksum = 1 + (~$checksum & 0x7fffffff) if ($checksum & 0x80000000); $checksum -= (($checksum * 1152921497) >> 60) * 1000000007; return scalar reverse sprintf("%x", $checksum & 0xffff); } print compute_short_name_hash($ARGV[0]); -- snap -- E.g., running that with the argument ".gitignore" will result in "250a" (which then becomes "gi250a" in the code). Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Jeff King <peff@peff.net>
2018-05-21is_hfs_dotgit: match other .git filesLibravatar Jeff King2-12/+51
Both verify_path() and fsck match ".git", ".GIT", and other variants specific to HFS+. Let's allow matching other special files like ".gitmodules", which we'll later use to enforce extra restrictions via verify_path() and fsck. Signed-off-by: Jeff King <peff@peff.net>
2018-05-21is_ntfs_dotgit: use a size_t for traversing stringLibravatar Jeff King1-1/+1
We walk through the "name" string using an int, which can wrap to a negative value and cause us to read random memory before our array (e.g., by creating a tree with a name >2GB, since "int" is still 32 bits even on most 64-bit platforms). Worse, this is easy to trigger during the fsck_tree() check, which is supposed to be protecting us from malicious garbage. Note one bit of trickiness in the existing code: we sometimes assign -1 to "len" at the end of the loop, and then rely on the "len++" in the for-loop's increment to take it back to 0. This is still legal with a size_t, since assigning -1 will turn into SIZE_MAX, which then wraps around to 0 on increment. Signed-off-by: Jeff King <peff@peff.net>
2018-05-21submodule-config: verify submodule names as pathsLibravatar Jeff King5-0/+143
Submodule "names" come from the untrusted .gitmodules file, but we blindly append them to $GIT_DIR/modules to create our on-disk repo paths. This means you can do bad things by putting "../" into the name (among other things). Let's sanity-check these names to avoid building a path that can be exploited. There are two main decisions: 1. What should the allowed syntax be? It's tempting to reuse verify_path(), since submodule names typically come from in-repo paths. But there are two reasons not to: a. It's technically more strict than what we need, as we really care only about breaking out of the $GIT_DIR/modules/ hierarchy. E.g., having a submodule named "foo/.git" isn't actually dangerous, and it's possible that somebody has manually given such a funny name. b. Since we'll eventually use this checking logic in fsck to prevent downstream repositories, it should be consistent across platforms. Because verify_path() relies on is_dir_sep(), it wouldn't block "foo\..\bar" on a non-Windows machine. 2. Where should we enforce it? These days most of the .gitmodules reads go through submodule-config.c, so I've put it there in the reading step. That should cover all of the C code. We also construct the name for "git submodule add" inside the git-submodule.sh script. This is probably not a big deal for security since the name is coming from the user anyway, but it would be polite to remind them if the name they pick is invalid (and we need to expose the name-checker to the shell anyway for our test scripts). This patch issues a warning when reading .gitmodules and just ignores the related config entry completely. This will generally end up producing a sensible error, as it works the same as a .gitmodules file which is missing a submodule entry (so "submodule update" will barf, but "git clone --recurse-submodules" will print an error but not abort the clone. There is one minor oddity, which is that we print the warning once per malformed config key (since that's how the config subsystem gives us the entries). So in the new test, for example, the user would see three warnings. That's OK, since the intent is that this case should never come up outside of malicious repositories (and then it might even benefit the user to see the message multiple times). Credit for finding this vulnerability and the proof of concept from which the test script was adapted goes to Etienne Stalmans. Signed-off-by: Jeff King <peff@peff.net>
2017-09-22Git 2.13.6Libravatar Junio C Hamano3-2/+19
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-09-22Sync with 2.12.5Libravatar Junio C Hamano9-56/+155
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-09-22Git 2.12.5Libravatar Junio C Hamano3-2/+19
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-09-22Sync with 2.11.4Libravatar Junio C Hamano8-56/+138
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-09-22Git 2.11.4Libravatar Junio C Hamano3-2/+19
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-09-22Sync with 2.10.5Libravatar Junio C Hamano7-56/+121
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-09-22Git 2.10.5Libravatar Junio C Hamano3-2/+19
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-09-22Merge branch 'jk/safe-pipe-capture' into maint-2.10Libravatar Junio C Hamano1-2/+2
2017-09-22Merge branch 'jk/cvsimport-quoting' into maint-2.10Libravatar Junio C Hamano1-0/+1
2017-09-22Merge branch 'jc/cvsserver' into maint-2.10Libravatar Junio C Hamano1-40/+37
2017-09-22Merge branch 'jk/git-shell-drop-cvsserver' into maint-2.10Libravatar Junio C Hamano3-14/+64
2017-09-12cvsimport: shell-quote variable used in backticksLibravatar Jeff King1-0/+1
We run `git rev-parse` though the shell, and quote its argument only with single-quotes. This prevents most metacharacters from being a problem, but misses the obvious case when $name itself has single-quotes in it. We can fix this by applying the usual shell-quoting formula. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-09-12archimport: use safe_pipe_capture for user inputLibravatar Jeff King1-2/+2
Refnames can contain shell metacharacters which need to be passed verbatim to sub-processes. Using safe_pipe_capture skips the shell entirely. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-09-12shell: drop git-cvsserver support by defaultLibravatar Jeff King3-14/+64
The git-cvsserver script is old and largely unmaintained these days. But git-shell allows untrusted users to run it out of the box, significantly increasing its attack surface. Let's drop it from git-shell's list of internal handlers so that it cannot be run by default. This is not backwards compatible. But given the age and development activity on CVS-related parts of Git, this is likely to impact very few users, while helping many more (i.e., anybody who runs git-shell and had no intention of supporting CVS). There's no configuration mechanism in git-shell for us to add a boolean and flip it to "off". But there is a mechanism for adding custom commands, and adding CVS support here is fairly trivial. Let's document it to give guidance to anybody who really is still running cvsserver. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-09-11cvsserver: use safe_pipe_capture for `constant commands` as wellLibravatar Junio C Hamano1-4/+4
This is not strictly necessary, but it is a good code hygiene. Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-09-11cvsserver: use safe_pipe_capture instead of backticksLibravatar joernchen1-11/+11
This makes the script pass arguments that are derived from end-user input in safer way when invoking subcommands. Reported-by: joernchen <joernchen@phenoelit.de> Signed-off-by: joernchen <joernchen@phenoelit.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-09-11cvsserver: move safe_pipe_capture() to the main packageLibravatar Junio C Hamano1-25/+22
As a preparation for replacing `command` with a call to this function from outside GITCVS::updater package, move it to the main package. Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-08-01Git 2.13.5Libravatar Junio C Hamano3-2/+6
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-08-01Merge tag 'v2.12.4' into maintLibravatar Junio C Hamano13-2/+126
2017-08-01Git 2.13.4Libravatar Junio C Hamano1-1/+1
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-07-31Preparation for 2.13.4 continuesLibravatar Junio C Hamano1-0/+18
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-07-31Merge branch 'ks/doc-fixes' into maintLibravatar Junio C Hamano2-10/+11
Doc clean-up. * ks/doc-fixes: doc: reformat the paragraph containing the 'cut-line' doc: camelCase the i18n config variables to improve readability
2017-07-31Merge branch 'jk/test-copy-bytes-fix' into maintLibravatar Junio C Hamano1-0/+1
A test fix. * jk/test-copy-bytes-fix: t: handle EOF in test_copy_bytes()
2017-07-31Merge branch 'pw/unquote-path-in-git-pm' into maintLibravatar Junio C Hamano3-43/+61
Code refactoring. * pw/unquote-path-in-git-pm: t9700: add tests for Git::unquote_path() Git::unquote_path(): throw an exception on bad path Git::unquote_path(): handle '\a' add -i: move unquote_path() to Git.pm
2017-07-31Merge branch 'jk/gc-pre-detach-under-hook' into maintLibravatar Junio C Hamano2-0/+25
We run an early part of "git gc" that deals with refs before daemonising (and not under lock) even when running a background auto-gc, which caused multiple gc processes attempting to run the early part at the same time. This is now prevented by running the early part also under the GC lock. * jk/gc-pre-detach-under-hook: gc: run pre-detach operations under lock
2017-07-31Merge branch 'jn/hooks-pre-rebase-sample-fix' into maintLibravatar Junio C Hamano1-3/+3
Code clean-up, that makes us in sync with Debian by one patch. * jn/hooks-pre-rebase-sample-fix: pre-rebase hook: capture documentation in a <<here document
2017-07-31Merge branch 'rs/progress-overall-throughput-at-the-end' into maintLibravatar Junio C Hamano1-2/+6
The progress meter did not give a useful output when we haven't had 0.5 seconds to measure the throughput during the interval. Instead show the overall throughput rate at the end, which is a much more useful number. * rs/progress-overall-throughput-at-the-end: progress: show overall rate in last update
2017-07-31Merge branch 'tb/push-to-cygwin-unc-path' into maintLibravatar Junio C Hamano5-0/+27
On Cygwin, similar to Windows, "git push //server/share/repository" ought to mean a repository on a network share that can be accessed locally, but this did not work correctly due to stripping the double slashes at the beginning. This may need to be heavily tested before it gets unleashed to the wild, as the change is at a fairly low-level code and would affect not just the code to decide if the push destination is local. There may be unexpected fallouts in the path normalization. * tb/push-to-cygwin-unc-path: cygwin: allow pushing to UNC paths
2017-07-31Merge branch 'rs/apply-avoid-over-reading' into maintLibravatar Junio C Hamano1-4/+2
Code cleanup. * rs/apply-avoid-over-reading: apply: use strcmp(3) for comparing strings in gitdiff_verify_name() apply: use starts_with() in gitdiff_verify_name()
2017-07-30Git 2.12.4Libravatar Junio C Hamano3-2/+6
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-07-30Merge tag 'v2.11.3' into maint-2.12Libravatar Junio C Hamano11-0/+116
Git 2.11.3
2017-07-30Merge branch 'jk/lib-proto-disable-cleanup' into maint-2.12Libravatar Junio C Hamano1-2/+6
2017-07-30Git 2.11.3Libravatar Junio C Hamano3-2/+6
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-07-30Merge tag 'v2.10.4' into maint-2.11Libravatar Junio C Hamano10-0/+112
Git 2.10.4
2017-07-30Git 2.10.4Libravatar Junio C Hamano3-2/+6
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-07-30Merge tag 'v2.9.5' into maint-2.10Libravatar Junio C Hamano9-0/+108
Git 2.9.5
2017-07-30Git 2.9.5Libravatar Junio C Hamano3-2/+6
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-07-30Merge tag 'v2.8.6' into maint-2.9Libravatar Junio C Hamano8-0/+104
Git 2.8.6
2017-07-30Git 2.8.6Libravatar Junio C Hamano3-2/+6
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-07-30Merge tag 'v2.7.6' into maint-2.8Libravatar Junio C Hamano7-0/+100
Git 2.7.6