Commit graph

11606 commits

Author SHA1 Message Date
Jeff King 53ce2e3f0a am: add explicit "--retry" option
After a patch fails, you can ask "git am" to try applying it again with
new options by running without any of the resume options. E.g.:

  git am <patch
  # oops, it failed; let's try again
  git am --3way

But since this second command has no explicit resume option (like
"--continue"), it looks just like an invocation to read a fresh patch
from stdin. To avoid confusing the two cases, there are some heuristics,
courtesy of 8d18550318 (builtin-am: reject patches when there's a
session in progress, 2015-08-04):

	if (in_progress) {
		/*
		 * Catch user error to feed us patches when there is a session
		 * in progress:
		 *
		 * 1. mbox path(s) are provided on the command-line.
		 * 2. stdin is not a tty: the user is trying to feed us a patch
		 *    from standard input. This is somewhat unreliable -- stdin
		 *    could be /dev/null for example and the caller did not
		 *    intend to feed us a patch but wanted to continue
		 *    unattended.
		 */
		if (argc || (resume_mode == RESUME_FALSE && !isatty(0)))
			die(_("previous rebase directory %s still exists but mbox given."),
				state.dir);

		if (resume_mode == RESUME_FALSE)
			resume_mode = RESUME_APPLY;
		[...]

So if no resume command is given, then we require that stdin be a tty,
and otherwise complain about (potentially) receiving an mbox on stdin.
But of course you might not actually have a terminal available! And
sadly there is no explicit way to hit this same code path; this is the
only place that sets RESUME_APPLY. So you're stuck, and scripts like our
test suite have to bend over backwards to create a pseudo-tty.

Let's provide an explicit option to trigger this mode. The code turns
out to be quite simple; just setting "resume_mode" to RESUME_FALSE is
enough to dodge the tty check, and then our state is the same as it
would be with the heuristic case (which we'll continue to allow).

When we don't have a session in progress, there's already code to
complain when resume_mode is set (but we'll add a new test to cover
that).

To test the new option, we'll convert the existing tests that rely on
the fake stdin tty. That lets us test them on more platforms, and will
let us simplify test_terminal a bit in a future patch.

It does, however, mean we're not testing the tty heuristic at all.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-06-06 10:07:41 -07:00
Junio C Hamano 3c562ef2e6 Merge branch 'fixes/2.45.1/2.42' into fixes/2.45.1/2.43
* fixes/2.45.1/2.42:
  Revert "fsck: warn about symlink pointing inside a gitdir"
  Revert "Add a helper function to compare file contents"
  clone: drop the protections where hooks aren't run
  tests: verify that `clone -c core.hooksPath=/dev/null` works again
  Revert "core.hooksPath: add some protection while cloning"
  init: use the correct path of the templates directory again
  hook: plug a new memory leak
  ci: stop installing "gcc-13" for osx-gcc
  ci: avoid bare "gcc" for osx-gcc job
  ci: drop mention of BREW_INSTALL_PACKAGES variable
  send-email: avoid creating more than one Term::ReadLine object
  send-email: drop FakeTerm hack
2024-05-24 16:58:11 -07:00
Junio C Hamano 73339e4dc2 Merge branch 'fixes/2.45.1/2.41' into fixes/2.45.1/2.42
* fixes/2.45.1/2.41:
  Revert "fsck: warn about symlink pointing inside a gitdir"
  Revert "Add a helper function to compare file contents"
  clone: drop the protections where hooks aren't run
  tests: verify that `clone -c core.hooksPath=/dev/null` works again
  Revert "core.hooksPath: add some protection while cloning"
  init: use the correct path of the templates directory again
  hook: plug a new memory leak
  ci: stop installing "gcc-13" for osx-gcc
  ci: avoid bare "gcc" for osx-gcc job
  ci: drop mention of BREW_INSTALL_PACKAGES variable
  send-email: avoid creating more than one Term::ReadLine object
  send-email: drop FakeTerm hack
2024-05-24 16:57:43 -07:00
Junio C Hamano 4f215d214f Merge branch 'fixes/2.45.1/2.40' into fixes/2.45.1/2.41
* fixes/2.45.1/2.40:
  Revert "fsck: warn about symlink pointing inside a gitdir"
  Revert "Add a helper function to compare file contents"
  clone: drop the protections where hooks aren't run
  tests: verify that `clone -c core.hooksPath=/dev/null` works again
  Revert "core.hooksPath: add some protection while cloning"
  init: use the correct path of the templates directory again
  hook: plug a new memory leak
  ci: stop installing "gcc-13" for osx-gcc
  ci: avoid bare "gcc" for osx-gcc job
  ci: drop mention of BREW_INSTALL_PACKAGES variable
  send-email: avoid creating more than one Term::ReadLine object
  send-email: drop FakeTerm hack
2024-05-24 16:57:02 -07:00
Junio C Hamano 48440f60a7 Merge branch 'jc/fix-2.45.1-and-friends-for-2.39' into fixes/2.45.1/2.40
Revert overly aggressive "layered defence" that went into 2.45.1
and friends, which broke "git-lfs", "git-annex", and other use
cases, so that we can rebuild necessary counterparts in the open.

* jc/fix-2.45.1-and-friends-for-2.39:
  Revert "fsck: warn about symlink pointing inside a gitdir"
  Revert "Add a helper function to compare file contents"
  clone: drop the protections where hooks aren't run
  tests: verify that `clone -c core.hooksPath=/dev/null` works again
  Revert "core.hooksPath: add some protection while cloning"
  init: use the correct path of the templates directory again
  hook: plug a new memory leak
  ci: stop installing "gcc-13" for osx-gcc
  ci: avoid bare "gcc" for osx-gcc job
  ci: drop mention of BREW_INSTALL_PACKAGES variable
  send-email: avoid creating more than one Term::ReadLine object
  send-email: drop FakeTerm hack
2024-05-24 12:29:36 -07:00
Johannes Schindelin 873a466ea3 clone: drop the protections where hooks aren't run
As part of the security bug-fix releases v2.39.4, ..., v2.45.1, I
introduced logic to safeguard `git clone` from running hooks that were
installed _during_ the clone operation.

The rationale was that Git's CVE-2024-32002, CVE-2021-21300,
CVE-2019-1354, CVE-2019-1353, CVE-2019-1352, and CVE-2019-1349 should
have been low-severity vulnerabilities but were elevated to
critical/high severity by the attack vector that allows a weakness where
files inside `.git/` can be inadvertently written during a `git clone`
to escalate to a Remote Code Execution attack by virtue of installing a
malicious `post-checkout` hook that Git will then run at the end of the
operation without giving the user a chance to see what code is executed.

Unfortunately, Git LFS uses a similar strategy to install its own
`post-checkout` hook during a `git clone`; In fact, Git LFS is
installing four separate hooks while running the `smudge` filter.

While this pattern is probably in want of being improved by introducing
better support in Git for Git LFS and other tools wishing to register
hooks to be run at various stages of Git's commands, let's undo the
clone protections to unbreak Git LFS-enabled clones.

This reverts commit 8db1e8743c (clone: prevent hooks from running
during a clone, 2024-03-28).

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-05-21 12:33:08 -07:00
Johannes Schindelin 8e97ec3662 Sync with 2.42.2
* maint-2.42: (39 commits)
  Git 2.42.2
  Git 2.41.1
  Git 2.40.2
  Git 2.39.4
  fsck: warn about symlink pointing inside a gitdir
  core.hooksPath: add some protection while cloning
  init.templateDir: consider this config setting protected
  clone: prevent hooks from running during a clone
  Add a helper function to compare file contents
  init: refactor the template directory discovery into its own function
  find_hook(): refactor the `STRIP_EXTENSION` logic
  clone: when symbolic links collide with directories, keep the latter
  entry: report more colliding paths
  t5510: verify that D/F confusion cannot lead to an RCE
  submodule: require the submodule path to contain directories only
  clone_submodule: avoid using `access()` on directories
  submodules: submodule paths must not contain symlinks
  clone: prevent clashing git dirs when cloning submodule in parallel
  t7423: add tests for symlinked submodule directories
  has_dir_name(): do not get confused by characters < '/'
  ...
2024-04-19 12:38:50 +02:00
Johannes Schindelin be348e9815 Sync with 2.41.1
* maint-2.41: (38 commits)
  Git 2.41.1
  Git 2.40.2
  Git 2.39.4
  fsck: warn about symlink pointing inside a gitdir
  core.hooksPath: add some protection while cloning
  init.templateDir: consider this config setting protected
  clone: prevent hooks from running during a clone
  Add a helper function to compare file contents
  init: refactor the template directory discovery into its own function
  find_hook(): refactor the `STRIP_EXTENSION` logic
  clone: when symbolic links collide with directories, keep the latter
  entry: report more colliding paths
  t5510: verify that D/F confusion cannot lead to an RCE
  submodule: require the submodule path to contain directories only
  clone_submodule: avoid using `access()` on directories
  submodules: submodule paths must not contain symlinks
  clone: prevent clashing git dirs when cloning submodule in parallel
  t7423: add tests for symlinked submodule directories
  has_dir_name(): do not get confused by characters < '/'
  docs: document security issues around untrusted .git dirs
  ...
2024-04-19 12:38:46 +02:00
Johannes Schindelin f5b2af06f5 Sync with 2.40.2
* maint-2.40: (39 commits)
  Git 2.40.2
  Git 2.39.4
  fsck: warn about symlink pointing inside a gitdir
  core.hooksPath: add some protection while cloning
  init.templateDir: consider this config setting protected
  clone: prevent hooks from running during a clone
  Add a helper function to compare file contents
  init: refactor the template directory discovery into its own function
  find_hook(): refactor the `STRIP_EXTENSION` logic
  clone: when symbolic links collide with directories, keep the latter
  entry: report more colliding paths
  t5510: verify that D/F confusion cannot lead to an RCE
  submodule: require the submodule path to contain directories only
  clone_submodule: avoid using `access()` on directories
  submodules: submodule paths must not contain symlinks
  clone: prevent clashing git dirs when cloning submodule in parallel
  t7423: add tests for symlinked submodule directories
  has_dir_name(): do not get confused by characters < '/'
  docs: document security issues around untrusted .git dirs
  upload-pack: disable lazy-fetching by default
  ...
2024-04-19 12:38:42 +02:00
Johannes Schindelin 93a88f42db Sync with 2.39.4
* maint-2.39: (38 commits)
  Git 2.39.4
  fsck: warn about symlink pointing inside a gitdir
  core.hooksPath: add some protection while cloning
  init.templateDir: consider this config setting protected
  clone: prevent hooks from running during a clone
  Add a helper function to compare file contents
  init: refactor the template directory discovery into its own function
  find_hook(): refactor the `STRIP_EXTENSION` logic
  clone: when symbolic links collide with directories, keep the latter
  entry: report more colliding paths
  t5510: verify that D/F confusion cannot lead to an RCE
  submodule: require the submodule path to contain directories only
  clone_submodule: avoid using `access()` on directories
  submodules: submodule paths must not contain symlinks
  clone: prevent clashing git dirs when cloning submodule in parallel
  t7423: add tests for symlinked submodule directories
  has_dir_name(): do not get confused by characters < '/'
  docs: document security issues around untrusted .git dirs
  upload-pack: disable lazy-fetching by default
  fetch/clone: detect dubious ownership of local repositories
  ...
2024-04-19 12:38:37 +02:00
Johannes Schindelin 9e65df5eab Merge branch 'ownership-checks-in-local-clones'
This topic addresses two CVEs:

- CVE-2024-32020:

  Local clones may end up hardlinking files into the target repository's
  object database when source and target repository reside on the same
  disk. If the source repository is owned by a different user, then
  those hardlinked files may be rewritten at any point in time by the
  untrusted user.

- CVE-2024-32021:

  When cloning a local source repository that contains symlinks via the
  filesystem, Git may create hardlinks to arbitrary user-readable files
  on the same filesystem as the target repository in the objects/
  directory.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2024-04-19 12:38:32 +02:00
Johannes Schindelin 8db1e8743c clone: prevent hooks from running during a clone
Critical security issues typically combine relatively common
vulnerabilities such as case confusion in file paths with other
weaknesses in order to raise the severity of the attack.

One such weakness that has haunted the Git project in many a
submodule-related CVE is that any hooks that are found are executed
during a clone operation. Examples are the `post-checkout` and
`fsmonitor` hooks.

However, Git's design calls for hooks to be disabled by default, as only
disabled example hooks are copied over from the templates in
`<prefix>/share/git-core/templates/`.

As a defense-in-depth measure, let's prevent those hooks from running.

Obviously, administrators can choose to drop enabled hooks into the
template directory, though, _and_ it is also possible to override
`core.hooksPath`, in which case the new check needs to be disabled.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2024-04-19 12:38:23 +02:00
Johannes Schindelin df93e407f0 init: refactor the template directory discovery into its own function
We will need to call this function from `hook.c` to be able to prevent
hooks from running that were written as part of a `clone` but did not
originate from the template directory.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2024-04-17 22:30:10 +02:00
Johannes Schindelin e8d0608944 submodule: require the submodule path to contain directories only
Submodules are stored in subdirectories of their superproject. When
these subdirectories have been replaced with symlinks by a malicious
actor, all kinds of mayhem can be caused.

This _should_ not be possible, but many CVEs in the past showed that
_when_ possible, it allows attackers to slip in code that gets executed
during, say, a `git clone --recursive` operation.

Let's add some defense-in-depth to disallow submodule paths to have
anything except directories in them.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2024-04-17 22:30:04 +02:00
Johannes Schindelin eafffd9ad4 clone_submodule: avoid using access() on directories
In 0060fd1511 (clone --recurse-submodules: prevent name squatting on
Windows, 2019-09-12), I introduced code to verify that a git dir either
does not exist, or is at least empty, to fend off attacks where an
inadvertently (and likely maliciously) pre-populated git dir would be
used while cloning submodules recursively.

The logic used `access(<path>, X_OK)` to verify that a directory exists
before calling `is_empty_dir()` on it. That is a curious way to check
for a directory's existence and might well fail for unwanted reasons.
Even the original author (it was I ;-) ) struggles to explain why this
function was used rather than `stat()`.

This code was _almost_ copypastad in the previous commit, but that
`access()` call was caught during review.

Let's use `stat()` instead also in the code that was almost copied
verbatim. Let's not use `lstat()` because in the unlikely event that
somebody snuck a symbolic link in, pointing to a crafted directory, we
want to verify that that directory is empty.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2024-04-17 22:30:03 +02:00
Johannes Schindelin 9706576133 submodules: submodule paths must not contain symlinks
When creating a submodule path, we must be careful not to follow
symbolic links. Otherwise we may follow a symbolic link pointing to
a gitdir (which are valid symbolic links!) e.g. while cloning.

On case-insensitive filesystems, however, we blindly replace a directory
that has been created as part of the `clone` operation with a symlink
when the path to the latter differs only in case from the former's path.

Let's simply avoid this situation by expecting not ever having to
overwrite any existing file/directory/symlink upon cloning. That way, we
won't even replace a directory that we just created.

This addresses CVE-2024-32002.

Reported-by: Filip Hejsek <filip.hejsek@gmail.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2024-04-17 22:30:02 +02:00
Filip Hejsek 9cf8547320 clone: prevent clashing git dirs when cloning submodule in parallel
While it is expected to have several git dirs within the `.git/modules/`
tree, it is important that they do not interfere with each other. For
example, if one submodule was called "captain" and another submodule
"captain/hooks", their respective git dirs would clash, as they would be
located in `.git/modules/captain/` and `.git/modules/captain/hooks/`,
respectively, i.e. the latter's files could clash with the actual Git
hooks of the former.

To prevent these clashes, and in particular to prevent hooks from being
written and then executed as part of a recursive clone, we introduced
checks as part of the fix for CVE-2019-1387 in a8dee3ca61 (Disallow
dubiously-nested submodule git directories, 2019-10-01).

It is currently possible to bypass the check for clashing submodule
git dirs in two ways:

1. parallel cloning
2. checkout --recurse-submodules

Let's check not only before, but also after parallel cloning (and before
checking out the submodule), that the git dir is not clashing with
another one, otherwise fail. This addresses the parallel cloning issue.

As to the parallel checkout issue: It requires quite a few manual steps
to create clashing git dirs because Git itself would refuse to
initialize the inner one, as demonstrated by the test case.

Nevertheless, let's teach the recursive checkout (namely, the
`submodule_move_head()` function that is used by the recursive checkout)
to be careful to verify that it does not use a clashing git dir, and if
it does, disable it (by deleting the `HEAD` file so that subsequent Git
calls won't recognize it as a git dir anymore).

Note: The parallel cloning test case contains a `cat err` that proved to
be highly useful when analyzing the racy nature of the operation (the
operation can fail with three different error messages, depending on
timing), and was left on purpose to ease future debugging should the
need arise.

Signed-off-by: Filip Hejsek <filip.hejsek@gmail.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2024-04-17 22:30:01 +02:00
Jeff King 7b70e9efb1 upload-pack: disable lazy-fetching by default
The upload-pack command tries to avoid trusting the repository in which
it's run (e.g., by not running any hooks and not using any config that
contains arbitrary commands). But if the server side of a fetch or a
clone is a partial clone, then either upload-pack or its child
pack-objects may run a lazy "git fetch" under the hood. And it is very
easy to convince fetch to run arbitrary commands.

The "server" side can be a local repository owned by someone else, who
would be able to configure commands that are run during a clone with the
current user's permissions. This issue has been designated
CVE-2024-32004.

The fix in this commit's parent helps in this scenario, as well as in
related scenarios using SSH to clone, where the untrusted .git directory
is owned by a different user id. But if you received one as a zip file,
on a USB stick, etc, it may be owned by your user but still untrusted.

This has been designated CVE-2024-32465.

To mitigate the issue more completely, let's disable lazy fetching
entirely during `upload-pack`. While fetching from a partial repository
should be relatively rare, it is certainly not an unreasonable workflow.
And thus we need to provide an escape hatch.

This commit works by respecting a GIT_NO_LAZY_FETCH environment variable
(to skip the lazy-fetch), and setting it in upload-pack, but only when
the user has not already done so (which gives us the escape hatch).

The name of the variable is specifically chosen to match what has
already been added in 'master' via e6d5479e7a (git: extend
--no-lazy-fetch to work across subprocesses, 2024-02-27). Since we're
building this fix as a backport for older versions, we could cherry-pick
that patch and its earlier steps. However, we don't really need the
niceties (like a "--no-lazy-fetch" option) that it offers. By using the
same name, everything should just work when the two are eventually
merged, but here are a few notes:

  - the blocking of the fetch in e6d5479e7a is incomplete! It sets
    fetch_if_missing to 0 when we setup the repository variable, but
    that isn't enough. pack-objects in particular will call
    prefetch_to_pack() even if that variable is 0. This patch by
    contrast checks the environment variable at the lowest level before
    we call the lazy fetch, where we can be sure to catch all code
    paths.

    Possibly the setting of fetch_if_missing from e6d5479e7a can be
    reverted, but it may be useful to have. For example, some code may
    want to use that flag to change behavior before it gets to the point
    of trying to start the fetch. At any rate, that's all outside the
    scope of this patch.

  - there's documentation for GIT_NO_LAZY_FETCH in e6d5479e7a. We can
    live without that here, because for the most part the user shouldn't
    need to set it themselves. The exception is if they do want to
    override upload-pack's default, and that requires a separate
    documentation section (which is added here)

  - it would be nice to use the NO_LAZY_FETCH_ENVIRONMENT macro added by
    e6d5479e7a, but those definitions have moved from cache.h to
    environment.h between 2.39.3 and master. I just used the raw string
    literals, and we can replace them with the macro once this topic is
    merged to master.

At least with respect to CVE-2024-32004, this does render this commit's
parent commit somewhat redundant. However, it is worth retaining that
commit as defense in depth, and because it may help other issues (e.g.,
symlink/hardlink TOCTOU races, where zip files are not really an
interesting attack vector).

The tests in t0411 still pass, but now we have _two_ mechanisms ensuring
that the evil command is not run. Let's beef up the existing ones to
check that they failed for the expected reason, that we refused to run
upload-pack at all with an alternate user id. And add two new ones for
the same-user case that both the restriction and its escape hatch.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2024-04-17 22:29:56 +02:00
Patrick Steinhardt 1204e1a824 builtin/clone: refuse local clones of unsafe repositories
When performing a local clone of a repository we end up either copying
or hardlinking the source repository into the target repository. This is
significantly more performant than if we were to use git-upload-pack(1)
and git-fetch-pack(1) to create the new repository and preserves both
disk space and compute time.

Unfortunately though, performing such a local clone of a repository that
is not owned by the current user is inherently unsafe:

  - It is possible that source files get swapped out underneath us while
    we are copying or hardlinking them. While we do perform some checks
    here to assert that we hardlinked the expected file, they cannot
    reliably thwart time-of-check-time-of-use (TOCTOU) style races. It
    is thus possible for an adversary to make us copy or hardlink
    unexpected files into the target directory.

    Ideally, we would address this by starting to use openat(3P),
    fstatat(3P) and friends. Due to platform compatibility with Windows
    we cannot easily do that though. Furthermore, the scope of these
    fixes would likely be quite broad and thus not fit for an embargoed
    security release.

  - Even if we handled TOCTOU-style races perfectly, hardlinking files
    owned by a different user into the target repository is not a good
    idea in general. It is possible for an adversary to rewrite those
    files to contain whatever data they want even after the clone has
    completed.

Address these issues by completely refusing local clones of a repository
that is not owned by the current user. This reuses our existing infra we
have in place via `ensure_valid_ownership()` and thus allows a user to
override the safety guard by adding the source repository path to the
"safe.directory" configuration.

This addresses CVE-2024-32020.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2024-04-17 02:17:40 +02:00
Patrick Steinhardt d1bb66a546 builtin/clone: abort when hardlinked source and target file differ
When performing local clones with hardlinks we refuse to copy source
files which are symlinks as a mitigation for CVE-2022-39253. This check
can be raced by an adversary though by changing the file to a symlink
after we have checked it.

Fix the issue by checking whether the hardlinked destination file
matches the source file and abort in case it doesn't.

This addresses CVE-2024-32021.

Reported-by: Apple Product Security <product-security@apple.com>
Suggested-by: Linus Torvalds <torvalds@linuxfoundation.org>
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2024-04-17 00:01:25 +02:00
Patrick Steinhardt 150e6b0aed builtin/clone: stop resolving symlinks when copying files
When a user performs a local clone without `--no-local`, then we end up
copying the source repository into the target repository directly. To
optimize this even further, we try to hardlink files into place instead
of copying data over, which helps both disk usage and speed.

There is an important edge case in this context though, namely when we
try to hardlink symlinks from the source repository into the target
repository. Depending on both platform and filesystem the resulting
behaviour here can be different:

  - On macOS and NetBSD, calling link(3P) with a symlink target creates
    a hardlink to the file pointed to by the symlink.

  - On Linux, calling link(3P) instead creates a hardlink to the symlink
    itself.

To unify this behaviour, 36596fd2df (clone: better handle symlinked
files at .git/objects/, 2019-07-10) introduced logic to resolve symlinks
before we try to link(3P) files. Consequently, the new behaviour was to
always create a hard link to the target of the symlink on all platforms.

Eventually though, we figured out that following symlinks like this can
cause havoc when performing a local clone of a malicious repository,
which resulted in CVE-2022-39253. This issue was fixed via 6f054f9fb3
(builtin/clone.c: disallow `--local` clones with symlinks, 2022-07-28),
by refusing symlinks in the source repository.

But even though we now shouldn't ever link symlinks anymore, the code
that resolves symlinks still exists. In the best case the code does not
end up doing anything because there are no symlinks anymore. In the
worst case though this can be abused by an adversary that rewrites the
source file after it has been checked not to be a symlink such that it
actually is a symlink when we call link(3P). Thus, it is still possible
to recreate CVE-2022-39253 due to this time-of-check-time-of-use bug.

Remove the call to `realpath()`. This doesn't yet address the actual
vulnerability, which will be handled in a subsequent commit.

Reported-by: Apple Product Security <product-security@apple.com>
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2024-04-17 00:01:25 +02:00
Junio C Hamano bd10c45672 Merge branch 'ps/report-failure-from-git-stash' into maint-2.43
"git stash" sometimes was silent even when it failed due to
unwritable index file, which has been corrected.

* ps/report-failure-from-git-stash:
  builtin/stash: report failure to write to index
2024-02-13 14:44:49 -08:00
Junio C Hamano 07fa383615 Merge branch 'jc/sign-buffer-failure-propagation-fix' into maint-2.43
A failed "git tag -s" did not necessarily result in an error
depending on the crypto backend, which has been corrected.

* jc/sign-buffer-failure-propagation-fix:
  ssh signing: signal an error with a negative return value
  tag: fix sign_buffer() call to create a signed tag
2024-02-13 14:44:48 -08:00
Junio C Hamano a1cd814f1f Merge branch 'jc/comment-style-fixes' into maint-2.43
Rewrite //-comments to /* comments */ in files whose comments
prevalently use the latter.

* jc/comment-style-fixes:
  reftable/pq_test: comment style fix
  merge-ort.c: comment style fix
  builtin/worktree: comment style fixes
2024-02-13 14:44:48 -08:00
Junio C Hamano 908fde12b0 Merge branch 'tc/show-ref-exists-fix' into maint-2.43
Update to a new feature recently added, "git show-ref --exists".

* tc/show-ref-exists-fix:
  builtin/show-ref: treat directory as non-existing in --exists
2024-02-13 14:44:47 -08:00
Junio C Hamano a064af6ef4 Merge branch 'jk/index-pack-lsan-false-positive-fix' into maint-2.43
Fix false positive reported by leak sanitizer.

* jk/index-pack-lsan-false-positive-fix:
  index-pack: spawn threads atomically
2024-02-08 16:22:12 -08:00
Junio C Hamano 232953b904 Merge branch 'rs/fast-import-simplify-mempool-allocation' into maint-2.43
Code simplification.

* rs/fast-import-simplify-mempool-allocation:
  fast-import: use mem_pool_calloc()
2024-02-08 16:22:11 -08:00
Junio C Hamano 0f7a10a3aa Merge branch 'en/header-cleanup' into maint-2.43
Remove unused header "#include".

* en/header-cleanup:
  treewide: remove unnecessary includes in source files
  treewide: add direct includes currently only pulled in transitively
  trace2/tr2_tls.h: remove unnecessary include
  submodule-config.h: remove unnecessary include
  pkt-line.h: remove unnecessary include
  line-log.h: remove unnecessary include
  http.h: remove unnecessary include
  fsmonitor--daemon.h: remove unnecessary includes
  blame.h: remove unnecessary includes
  archive.h: remove unnecessary include
  treewide: remove unnecessary includes in source files
  treewide: remove unnecessary includes from header files
2024-02-08 16:22:10 -08:00
Junio C Hamano 974c9369aa Merge branch 'jc/orphan-unborn' into maint-2.43
Doc updates to clarify what an "unborn branch" means.

* jc/orphan-unborn:
  orphan/unborn: fix use of 'orphan' in end-user facing messages
  orphan/unborn: add to the glossary and use them consistently
2024-02-08 16:22:10 -08:00
Junio C Hamano 541d0d75e7 Merge branch 'la/trailer-cleanups' into maint-2.43
Code clean-up.

* la/trailer-cleanups:
  trailer: use offsets for trailer_start/trailer_end
  trailer: find the end of the log message
  commit: ignore_non_trailer computes number of bytes to ignore
2024-02-08 16:22:09 -08:00
Junio C Hamano edf4c0d42b Merge branch 'jc/retire-cas-opt-name-constant' into maint-2.43
Code clean-up.

* jc/retire-cas-opt-name-constant:
  remote.h: retire CAS_OPT_NAME
2024-02-08 16:22:09 -08:00
Junio C Hamano 2873a9686c Merge branch 'rs/rebase-use-strvec-pushf' into maint-2.43
Code clean-up.

* rs/rebase-use-strvec-pushf:
  rebase: use strvec_pushf() for format-patch revisions
2024-02-08 16:22:09 -08:00
Junio C Hamano b471ea3a0d Merge branch 'jk/config-cleanup' into maint-2.43
Code clean-up around use of configuration variables.

* jk/config-cleanup:
  sequencer: simplify away extra git_config_string() call
  gpg-interface: drop pointless config_error_nonbool() checks
  push: drop confusing configset/callback redundancy
  config: use git_config_string() for core.checkRoundTripEncoding
  diff: give more detailed messages for bogus diff.* config
  config: use config_error_nonbool() instead of custom messages
  imap-send: don't use git_die_config() inside callback
  git_xmerge_config(): prefer error() to die()
  config: reject bogus values for core.checkstat
2024-02-08 16:22:07 -08:00
Junio C Hamano 6479e121c2 Merge branch 'rs/incompatible-options-messages' into maint-2.43
Clean-up code that handles combinations of incompatible options.

* rs/incompatible-options-messages:
  worktree: simplify incompatibility message for --orphan and commit-ish
  worktree: standardize incompatibility messages
  clean: factorize incompatibility message
  revision, rev-parse: factorize incompatibility messages about - -exclude-hidden
  revision: use die_for_incompatible_opt3() for - -graph/--reverse/--walk-reflogs
  repack: use die_for_incompatible_opt3() for -A/-k/--cruft
  push: use die_for_incompatible_opt4() for - -delete/--tags/--all/--mirror
2024-02-08 16:22:06 -08:00
Junio C Hamano a7ea468346 Merge branch 'rs/column-leakfix' into maint-2.43
Leakfix.

* rs/column-leakfix:
  column: release strbuf and string_list after use
2024-02-08 16:22:06 -08:00
Junio C Hamano 25e2039cf6 Merge branch 'rs/i18n-cannot-be-used-together' into maint-2.43
Clean-up code that handles combinations of incompatible options.

* rs/i18n-cannot-be-used-together:
  i18n: factorize even more 'incompatible options' messages
2024-02-08 16:22:05 -08:00
Junio C Hamano 173d7746f6 Merge branch 'jb/reflog-expire-delete-dry-run-options' into maint-2.43
Command line parsing fix for "git reflog".

* jb/reflog-expire-delete-dry-run-options:
  builtin/reflog.c: fix dry-run option short name
2024-02-08 16:22:05 -08:00
Junio C Hamano 8566311a03 Merge branch 'jc/sparse-checkout-set-default-fix' into maint-2.43
"git sparse-checkout set" added default patterns even when the
patterns are being fed from the standard input, which has been
corrected.

* jc/sparse-checkout-set-default-fix:
  sparse-checkout: use default patterns for 'set' only !stdin
2024-02-08 16:22:04 -08:00
Junio C Hamano ce54593289 Merge branch 'jx/fetch-atomic-error-message-fix' into maint-2.43
"git fetch --atomic" issued an unnecessary empty error message,
which has been corrected.
cf. <ZX__e7VjyLXIl-uV@tanuki>

* jx/fetch-atomic-error-message-fix:
  fetch: no redundant error message for atomic fetch
  t5574: test porcelain output of atomic fetch
2024-02-08 16:22:03 -08:00
Junio C Hamano 952916f9e0 Merge branch 'rs/show-ref-incompatible-options' into maint-2.43
Code clean-up for sanity checking of command line options for "git
show-ref".

* rs/show-ref-incompatible-options:
  show-ref: use die_for_incompatible_opt3()
2024-02-08 16:22:03 -08:00
Junio C Hamano 28b47452b3 Merge branch 'jk/implicit-true' into maint-2.43
Some codepaths did not correctly parse configuration variables
specified with valueless "true", which has been corrected.

* jk/implicit-true:
  fsck: handle NULL value when parsing message config
  trailer: handle NULL value when parsing trailer-specific config
  submodule: handle NULL value when parsing submodule.*.branch
  help: handle NULL value for alias.* config
  trace2: handle NULL values in tr2_sysenv config callback
  setup: handle NULL value when parsing extensions
  config: handle NULL value when parsing non-bools
2024-02-08 16:22:03 -08:00
Junio C Hamano 5baedc68b0 Merge branch 'jk/bisect-reset-fix' into maint-2.43
"git bisect reset" has been taught to clean up state files and refs
even when BISECT_START file is gone.

* jk/bisect-reset-fix:
  bisect: always clean on reset
2024-02-08 16:22:03 -08:00
Junio C Hamano abfbff61ef tag: fix sign_buffer() call to create a signed tag
The command "git tag -s" internally calls sign_buffer() to make a
cryptographic signature using the chosen backend like GPG and SSH.
The internal helper functions used by "git tag" implementation seem
to use a "negative return values are errors, zero or positive return
values are not" convention, and there are places (e.g., verify_tag()
that calls gpg_verify_tag()) that these internal helper functions
translate return values that signal errors to conform to this
convention, but do_sign() that calls sign_buffer() forgets to do so.

Fix it, so that a failed call to sign_buffer() that can return the
exit status from pipe_command() will not be overlooked.

Reported-by: Sergey Kosukhin <skosukhin@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-02-07 10:47:25 -08:00
Patrick Steinhardt d2058cb2f0 builtin/stash: report failure to write to index
The git-stash(1) command needs to write to the index for many of its
operations. When the index is locked by a concurrent writer it will thus
fail to operate, which is expected. What is not expected though is that
we do not print any error message at all in this case. The user can thus
easily miss the fact that the command didn't do what they expected it to
do and would be left wondering why that is.

Fix this bug and report failures to write to the index. Add tests for
the subcommands which hit the respective code paths.

While at it, unify error messages when writing to the index fails. The
chosen error message is already used in "builtin/stash.c".

Reported-by: moti sd <motisd8@gmail.com>
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-02-06 12:08:38 -08:00
Junio C Hamano 777f783841 builtin/worktree: comment style fixes
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-01-29 14:08:52 -08:00
Toon Claes 0aabeaa562 builtin/show-ref: treat directory as non-existing in --exists
9080a7f178 (builtin/show-ref: add new mode to check for reference
existence, 2023-10-31) added the option --exists to git-show-ref(1).

When you use this option against a ref that doesn't exist, but it is
a parent directory of an existing ref, you get the following error:

    $ git show-ref --exists refs/heads
    error: failed to look up reference: Is a directory

when the ref-files backend is in use.  To be more clear to user,
hide the error about having found a directory.  What matters to the
user is that the named ref does not exist.  Instead, print the same
error as when the ref was not found:

    error: reference does not exist

Signed-off-by: Toon Claes <toon@iotcl.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-01-18 11:17:25 -08:00
Jeff King 993d38a066 index-pack: spawn threads atomically
The t5309 script triggers a racy false positive with SANITIZE=leak on a
multi-core system. Running with "--stress --run=6" usually fails within
10 seconds or so for me, complaining with something like:

    + git index-pack --fix-thin --stdin
    fatal: REF_DELTA at offset 46 already resolved (duplicate base 01d7713666f4de822776c7622c10f1b07de280dc?)

    =================================================================
    ==3904583==ERROR: LeakSanitizer: detected memory leaks

    Direct leak of 32 byte(s) in 1 object(s) allocated from:
        #0 0x7fa790d01986 in __interceptor_realloc ../../../../src/libsanitizer/lsan/lsan_interceptors.cpp:98
        #1 0x7fa790add769 in __pthread_getattr_np nptl/pthread_getattr_np.c:180
        #2 0x7fa790d117c5 in __sanitizer::GetThreadStackTopAndBottom(bool, unsigned long*, unsigned long*) ../../../../src/libsanitizer/sanitizer_common/sanitizer_linux_libcdep.cpp:150
        #3 0x7fa790d11957 in __sanitizer::GetThreadStackAndTls(bool, unsigned long*, unsigned long*, unsigned long*, unsigned long*) ../../../../src/libsanitizer/sanitizer_common/sanitizer_linux_libcdep.cpp:598
        #4 0x7fa790d03fe8 in __lsan::ThreadStart(unsigned int, unsigned long long, __sanitizer::ThreadType) ../../../../src/libsanitizer/lsan/lsan_posix.cpp:51
        #5 0x7fa790d013fd in __lsan_thread_start_func ../../../../src/libsanitizer/lsan/lsan_interceptors.cpp:440
        #6 0x7fa790adc3eb in start_thread nptl/pthread_create.c:444
        #7 0x7fa790b5ca5b in clone3 ../sysdeps/unix/sysv/linux/x86_64/clone3.S:81

    SUMMARY: LeakSanitizer: 32 byte(s) leaked in 1 allocation(s).
    Aborted

What happens is this:

  0. We construct a bogus pack with a duplicate object in it and trigger
     index-pack.

  1. We spawn a bunch of worker threads to resolve deltas (on my system
     it is 16 threads).

  2. One of the threads sees the duplicate object and bails by calling
     exit(), taking down all of the threads. This is expected and is the
     point of the test.

  3. At the time exit() is called, we may still be spawning threads from
     the main process via pthread_create(). LSan hooks thread creation
     to update its book-keeping; it has to know where each thread's
     stack is (so it can find entry points for reachable memory). So it
     calls pthread_getattr_np() to get information about the new thread.
     That may allocate memory that must be freed with a matching call to
     pthread_attr_destroy(). Probably LSan does that immediately, but
     if you're unlucky enough, the exit() will happen while it's between
     those two calls, and the allocated pthread_attr_t appears as a
     leak.

This isn't a real leak. It's not even in our code, but rather in the
LSan instrumentation code. So we could just ignore it. But the false
positive can cause people to waste time tracking it down.

It's possibly something that LSan could protect against (e.g., cover the
getattr/destroy pair with a mutex, and then in the final post-exit()
check for leaks try to take the same mutex). But I don't know enough
about LSan to say if that's a reasonable approach or not (or if my
analysis is even completely correct).

In the meantime, it's pretty easy to avoid the race by making creation
of the worker threads "atomic". That is, we'll spawn all of them before
letting any of them start to work. That's easy to do because we already
have a work_lock() mutex for handing out that work. If the main process
takes it, then all of the threads will immediately block until we've
finished spawning and released it.

This shouldn't make any practical difference for non-LSan runs. The
thread spawning is quick, and could happen before any worker thread gets
scheduled anyway.

Probably other spots that use threads are subject to the same issues.
But since we have to manually insert locking (and since this really is
kind of a hack), let's not bother with them unless somebody experiences
a similar racy false-positive in practice.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-01-05 08:40:56 -08:00
Junio C Hamano 53ded839ae sparse-checkout: use default patterns for 'set' only !stdin
"git sparse-checkout set ---no-cone" uses default patterns when none
is given from the command line, but it should do so ONLY when
--stdin is not being used.  Right now, add_patterns_from_input()
called when reading from the standard input is sloppy and does not
check if there are extra command line parameters that the command
will silently ignore, but that will change soon and not setting this
unnecessary and unused default patterns start to matter when it gets
fixed.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
2023-12-26 12:15:58 -08:00
Elijah Newren d57c671a51 treewide: remove unnecessary includes in source files
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2023-12-26 12:04:33 -08:00
Elijah Newren ec2101abf3 treewide: add direct includes currently only pulled in transitively
The next commit will remove a bunch of unnecessary includes, but to do
so, we need some of the lower level direct includes that files rely on
to be explicitly specified.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2023-12-26 12:04:32 -08:00