The previous commits disabled NTLM authentication by default due to its
cryptographic weaknesses. Users can re-enable it via the config setting
http.<url>.allowNTLMAuth, but this requires manual intervention.
Credential helpers may have knowledge about which servers are trusted
for NTLM authentication (e.g., known on-prem Azure DevOps instances).
To allow them to signal this trust, introduce a simple negotiation:
when NTLM is suppressed and the server offered it, Git advertises
ntlm=suppressed to the credential helper. The helper can respond with
ntlm=allow to re-enable NTLM for this request.
This happens precisely at the point where we would otherwise warn the
user about NTLM being suppressed, ensuring the capability is only
advertised when relevant.
Helped-by: Matthew John Cheetham <mjcheetham@outlook.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
The new default of Git is to disable NTLM authentication by default.
To help users find the escape hatch of that config setting, should they
need it, suggest it when the authentication failed and the server had
offered NTLM, i.e. if re-enabling it would fix the problem.
Helped-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
NTLM authentication is relatively weak. This is the case even with the
default setting of modern Windows versions, where NTLMv1 and LanManager
are disabled and only NTLMv2 is enabled: NTLMv2 hashes of even
reasonably complex 8-character passwords can be broken in a matter of
days, given enough compute resources.
Even worse: On Windows, NTLM authentication uses Security Support
Provider Interface ("SSPI"), which provides the credentials without
requiring the user to type them in.
Which means that an attacker could talk an unsuspecting user into
cloning from a server that is under the attacker's control and extracts
the user's NTLMv2 hash without their knowledge.
For that reason, let's disallow NTLM authentication by default.
NTLM authentication is quite simple to set up, though, and therefore
there are still some on-prem Azure DevOps setups out there whose users
and/or automation rely on this type of authentication. To give them an
escape hatch, introduce the `http.<url>.allowNTLMAuth` config setting
that can be set to `true` to opt back into using NTLM for a specific
remote repository.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Although NTLM authentication is considered weak (extending even to
NTLMv2, which purportedly allows brute-forcing reasonably complex
8-character passwords in a matter of days, given ample compute
resources), it _is_ one of the authentication methods supported by
libcurl.
Note: The added test case *cannot* reuse the existing `custom_auth`
facility. The reason is that that facility is backed by an NPH script
("No Parse Headers"), which does not allow handling the 3-phase NTLM
authentication correctly (in my hands, the NPH script would not even be
called upon the Type 3 message, a "200 OK" would be returned, but no
headers, let alone the `git http-backend` output as payload). Having a
separate NTLM authentication script makes the exact workings clearer and
more readable, anyway.
Co-authored-by: Matthew John Cheetham <mjcheetham@outlook.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
These fixes have been sent to the Git mailing list but have not been
picked up by the Git project yet.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
This addresses:
- CVE-2024-52005:
Insufficient neutralization of ANSI escape sequences in sideband
payload can be used to mislead Git users into believing that
certain remote-generated messages actually originate from Git.
Signed-off-by: Johannes Schindelin <Johannes.Schindelin@gmx.de>
In some implementations, `regexec_buf()` assumes that it is fed lines;
Without `REG_NOTEOL` it thinks the end of the buffer is the end of a
line. Which makes sense, but trips up this case because we are not
feeding lines, but rather a whole buffer. So the final newline is not
the start of an empty line, but the true end of the buffer.
This causes an interesting bug:
$ echo content >file.txt
$ git grep --no-index -n '^$' file.txt
file.txt:2:
This bug is fixed by making the end of the buffer consistently the end
of the final line.
The patch was applied from
https://lore.kernel.org/git/20250113062601.GD767856@coredump.intra.peff.net/
Reported-by: Olly Betts <olly@survex.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
When a Unix socket is initialized, the current directory's path is
stored so that the cleanup code can `chdir()` back to where it was
before exit.
If the path that needs to be stored exceeds the default size of the
`sun_path` attribute of `struct sockaddr_un` (which is defined as a
108-sized byte array on Linux), a larger buffer needs to be allocated so
that it can hold the path, and it is the responsibility of the
`unix_sockaddr_cleanup()` function to release that allocated memory.
In Git's CI, this stack allocation is not necessary because the code is
checked out to `/home/runner/work/git/git`. Concatenate the path
`t/trash directory.t0301-credential-cache/.cache/git/credential/socket`
and a terminating NUL, and you end up with 96 bytes, 12 shy of the
default `sun_path` size.
However, I use worktrees with slightly longer paths:
`/home/me/projects/git/yes/i/nest/worktrees/to/organize/them/` is more
in line with what I have. When I recently tried to locally reproduce a
failure of the `linux-leaks` CI job, this t0301 test failed (where it
had not failed in CI).
The reason: When `credential-cache` tries to reach its daemon initially
by calling `unix_sockaddr_init()`, it is expected that the daemon cannot
be reached (the idea is to spin up the daemon in that case and try
again). However, when this first call to `unix_sockaddr_init()` fails,
the code returns early from the `unix_stream_connect()` function
_without_ giving the cleanup code a chance to run, skipping the
deallocation of above-mentioned path.
The fix is easy: do not return early but instead go directly to the
cleanup code.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
The preceding two commits introduced special handling of the sideband
channel to neutralize ANSI escape sequences before sending the payload
to the terminal, and `sideband.allowControlCharacters` to override that
behavior.
However, some `pre-receive` hooks that are actively used in practice
want to color their messages and therefore rely on the fact that Git
passes them through to the terminal.
In contrast to other ANSI escape sequences, it is highly unlikely that
coloring sequences can be essential tools in attack vectors that mislead
Git users e.g. by hiding crucial information.
Therefore we can have both: Continue to allow ANSI coloring sequences to
be passed to the terminal, and neutralize all other ANSI escape
sequences.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
The preceding commit fixed the vulnerability whereas sideband messages
(that are under the control of the remote server) could contain ANSI
escape sequences that would be sent to the terminal verbatim.
However, this fix may not be desirable under all circumstances, e.g.
when remote servers deliberately add coloring to their messages to
increase their urgency.
To help with those use cases, give users a way to opt-out of the
protections: `sideband.allowControlCharacters`.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
The output of `git clone` is a vital component for understanding what
has happened when things go wrong. However, these logs are partially
under the control of the remote server (via the "sideband", which
typically contains what the remote `git pack-objects` process sends to
`stderr`), and is currently not sanitized by Git.
This makes Git susceptible to ANSI escape sequence injection (see
CWE-150, https://cwe.mitre.org/data/definitions/150.html), which allows
attackers to corrupt terminal state, to hide information, and even to
insert characters into the input buffer (i.e. as if the user had typed
those characters).
To plug this vulnerability, disallow any control character in the
sideband, replacing them instead with the common `^<letter/symbol>`
(e.g. `^[` for `\x1b`, `^A` for `\x01`).
There is likely a need for more fine-grained controls instead of using a
"heavy hammer" like this, which will be introduced subsequently.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
In commit ec0becacc9 (run-command: add stdin callback for
parallelization, 2026-01-28), we taught run_processes_parallel() to
ignore SIGPIPE, since we wouldn't want a write() to a broken pipe of one
of the children to take down the whole process.
But there's a subtle ordering issue. After we ignore SIGPIPE, we call
pp_init(), which installs its own cleanup handler for multiple signals
using sigchain_push_common(), which includes SIGPIPE. So if we receive
SIGPIPE while writing to a child, we'll trigger that handler first, pop
it off the stack, and then re-raise (which is then ignored because of
the SIG_IGN we pushed first).
But what does that handler do? It tries to clean up all of the child
processes, under the assumption that when we re-raise the signal we'll
be exiting the process!
So a hook that exits without reading all of its input will cause us to
get SIGPIPE, which will put us in a signal handler that then tries to
kill() that same child.
This seems to be mostly harmless on Linux. The process has already
exited by this point, and though kill() does not complain (since the
process has not been reaped with a wait() call), it does not affect the
exit status of the process.
However, this seems not to be true on all platforms. This case is
triggered by t5401.13, "pre-receive hook that forgets to read its
input". This test fails on NonStop since that hook was converted to the
run_processes_parallel() API.
We can fix it by reordering the code a bit. We should run pp_init()
first, and then push our SIG_IGN onto the stack afterwards, so that it
is truly ignored while feeding the sub-processes.
Note that we also reorder the popping at the end of the function, too.
This is not technically necessary, as we are doing two pops either way,
but now the pops will correctly match their pushes.
This also fixes a related case that we can't test yet. If we did have
more than one process to run, then one child causing SIGPIPE would cause
us to kill() all of the children (which might still actually be
running). But the hook API is the only user of the new feed_pipe
feature, and it does not yet support parallel hook execution. So for now
we'll always execute the processes sequentially. Once parallel hook
execution exists, we'll be able to add a test which covers this.
Reported-by: Randall S. Becker <rsbecker@nexbridge.com>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
During Git 2.52 timeframe, we broke streaming computation of object
hash outside a repository, which has been corrected.
* jt/index-fd-wo-repo-regression-fix:
During Git 2.52 timeframe, we broke streaming computation of object
hash outside a repository, which has been corrected.
* jt/index-fd-wo-repo-regression-fix-maint:
object-file: avoid ODB transaction when not writing objects
The experimental `git replay` command learned the `--ref=<ref>` option
to allow specifying which ref to update, overriding the default behavior.
* tc/replay-ref:
replay: allow to specify a ref with option --ref
replay: use stuck form in documentation and help message
builtin/replay: mark options as not negatable
add_files_to_cache() used diff_files() to detect only the paths that
are different between the index and the working tree and add them,
which does not need rename detection, which interfered with unnecessary
conflicts.
* ng/add-files-to-cache-wo-rename:
read-cache: disable renames in add_files_to_cache
Update reftable library part with what is used in libgit2 to improve
portability to different target codebases and platforms.
* ps/reftable-portability:
reftable/system: add abstraction to mmap files
reftable/system: add abstraction to retrieve time in milliseconds
reftable/fsck: use REFTABLE_UNUSED instead of UNUSED
reftable/stack: provide fsync(3p) via system header
reftable: introduce "reftable-system.h" header
Various code clean-up around odb subsystem.
* ps/odb-cleanup:
odb: drop unneeded headers and forward decls
odb: rename `odb_has_object()` flags
odb: use enum for `odb_write_object` flags
odb: rename `odb_write_object()` flags
treewide: use enum for `odb_for_each_object()` flags
CodingGuidelines: document our style for flags
Add the missing &&'s so we properly propagate failures
between commands in the hook helper functions.
Also add a missing mkdir -p arg (found by adding the &&).
Reported-by: SZEDER Gábor <szeder.dev@gmail.com>
Signed-off-by: Adrian Ratiu <adrian.ratiu@collabora.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In ce1661f9da (odb: add transaction interface, 2025-09-16), existing
ODB transaction logic is adapted to create a transaction interface
at the ODB layer. The intent here is for the ODB transaction
interface to eventually provide an object source agnostic means to
manage transactions.
An unintended consequence of this change though is that
`object-file.c:index_fd()` may enter the ODB transaction path even
when no object write is requested. In non-repository contexts, this
can result in a NULL dereference and segfault. One such case occurs
when running git-diff(1) outside of a repository with
"core.bigFileThreshold" forcing the streaming path in `index_fd()`:
$ echo foo >foo
$ echo bar >bar
$ git -c core.bigFileThreshold=1 diff -- foo bar
In this scenario, the caller only needs to compute the object ID. Object
hashing does not require an ODB, so starting a transaction is both
unnecessary and invalid.
Fix the bug by avoiding the use of ODB transactions in `index_fd()` when
callers are only interested in computing the object hash.
Reported-by: Luca Stefani <luca.stefani.ge1@gmail.com>
Signed-off-by: Justin Tobler <jltobler@gmail.com>
[jc: adjusted to fd13909e (Merge branch 'jt/odb-transaction', 2025-10-02)]
Signed-off-by: Junio C Hamano <gitster@pobox.com>
"git backfill" is capable of auto-detecting a sparsely checked out
working tree, which was broken.
* th/backfill-auto-detect-sparseness-fix:
backfill: auto-detect sparse-checkout from config
The check in "receive-pack" to prevent a checked out branch from
getting updated via updateInstead mechanism has been corrected.
* ps/receive-pack-updateinstead-in-worktree:
receive-pack: use worktree HEAD for updateInstead
t5516: clean up cloned and new-wt in denyCurrentBranch and worktrees test
t5516: test updateInstead with worktree and unborn bare HEAD
Handling of signed commits and tags in fast-import has been made more
configurable.
* jt/fast-import-signed-modes:
fast-import: add 'abort-if-invalid' mode to '--signed-tags=<mode>'
fast-import: add 'sign-if-invalid' mode to '--signed-tags=<mode>'
fast-import: add 'strip-if-invalid' mode to '--signed-tags=<mode>'
fast-import: add 'abort-if-invalid' mode to '--signed-commits=<mode>'
fast-export: check for unsupported signing modes earlier
The way the "git log -L<range>:<file>" feature is bolted onto the
log/diff machinery is being reworked a bit to make the feature
compatible with more diff options, like -S/G.
* mm/line-log-use-standard-diff-output:
doc: note that -L supports patch formatting and pickaxe options
t4211: add tests for -L with standard diff options
line-log: route -L output through the standard diff pipeline
line-log: fix crash when combined with pickaxe options
Reduce dependency on `the_repository` in add-patch.c file.
* sp/add-patch-with-fewer-the-repository:
add-patch: use repository instance from add_i_state instead of the_repository
Internals of "git fsck" have been refactored to not depend on the
global `the_repository` variable.
* ps/fsck-wo-the-repository:
builtin/fsck: stop using `the_repository` in error reporting
builtin/fsck: stop using `the_repository` when marking objects
builtin/fsck: stop using `the_repository` when checking packed objects
builtin/fsck: stop using `the_repository` with loose objects
builtin/fsck: stop using `the_repository` when checking reflogs
builtin/fsck: stop using `the_repository` when checking refs
builtin/fsck: stop using `the_repository` when snapshotting refs
builtin/fsck: fix trivial dependence on `the_repository`
fsck: drop USE_THE_REPOSITORY
fsck: store repository in fsck options
fsck: initialize fsck options via a function
fetch-pack: move fsck options into function scope
The value of a wrong pointer variable was referenced in an error
message that reported that it shouldn't be NULL.
* yc/path-walk-fix-error-reporting:
path-walk: fix NULL pointer dereference in error message
Fix a regression in writing the commit-graph where commits with dates
exceeding 34 bits (beyond year 2514) could cause an underflow and
crash Git during the generation data overflow chunk writing.
* ps/commit-graph-overflow-fix:
commit-graph: fix writing generations with dates exceeding 34 bits
A handful of inappropriate uses of the_repository have been
rewritten to use the right repository structure instance in the
read-cache.c codepath.
* jd/read-cache-trace-wo-the-repository:
read-cache: use istate->repo for trace2 logging
Adjust the codebase for C23 that changes functions like strchr()
that discarded constness when they return a pointer into a const
string to preserve constness.
* jk/c23-const-preserving-fixes:
config: store allocated string in non-const pointer
rev-parse: avoid writing to const string for parent marks
revision: avoid writing to const string for parent marks
rev-parse: simplify dotdot parsing
revision: make handle_dotdot() interface less confusing
A few code paths that spawned child processes for network
connection weren't wait(2)ing for their children and letting "init"
reap them instead; they have been tightened.
* aa/reap-transport-child-processes:
transport-helper, connect: use clean_on_exit to reap children on abnormal exit
pack-objects's --stdin-packs=follow mode learns to handle
excluded-but-open packs.
* tb/stdin-packs-excluded-but-open:
repack: mark non-MIDX packs above the split as excluded-open
pack-objects: support excluded-open packs with --stdin-packs
t7704: demonstrate failure with once-cruft objects above the geometric split
pack-objects: refactor `read_packs_list_from_stdin()` to use `strmap`
pack-objects: plug leak in `read_stdin_packs()`
Object name handling (disambiguation and abbreviation) has been
refactored to be backend-generic, moving logic into the respective
object database backends.
* ps/odb-generic-object-name-handling:
odb: introduce generic `odb_find_abbrev_len()`
object-file: move logic to compute packed abbreviation length
object-name: move logic to compute loose abbreviation length
object-name: simplify computing common prefixes
object-name: abbreviate loose object names without `disambiguate_state`
object-name: merge `update_candidates()` and `match_prefix()`
object-name: backend-generic `get_short_oid()`
object-name: backend-generic `repo_collect_ambiguous()`
object-name: extract function to parse object ID prefixes
object-name: move logic to iterate through packed prefixed objects
object-name: move logic to iterate through loose prefixed objects
odb: introduce `struct odb_for_each_object_options`
oidtree: extend iteration to allow for arbitrary return codes
oidtree: modernize the code a bit
object-file: fix sparse 'plain integer as NULL pointer' error
"print" is not a valid argument for --update-refs. List both valid
alternatives literally in the argh string, consistent with documentation
and usage string.
Signed-off-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
1edeb9a (Win32: warn if the console font doesn't support Unicode,
2014-06-10) introduced both code to detect the current console font on
Windows Vista and newer and a fallback for older systems to detect the
default console font and issue a warning if that font doesn't support
unicode.
Since we haven't supported any Windows older than Vista in almost a
decade, we don't need to keep the workaround.
Signed-off-by: Matthias Aßhauer <mha1993@live.de>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
