Commit graph

270 commits

Author SHA1 Message Date
Johannes Schindelin
e394a16023 interpolate_path(): allow specifying paths relative to the runtime prefix
Ever since Git learned to detect its install location at runtime, there
was the slightly awkward problem that it was impossible to specify paths
relative to said location.

For example, if a version of Git was shipped with custom SSL
certificates to use, there was no portable way to specify
`http.sslCAInfo`.

In Git for Windows, the problem was "solved" for years by interpreting
paths starting with a slash as relative to the runtime prefix.

However, this is not correct: such paths _are_ legal on Windows, and
they are interpreted as absolute paths in the same drive as the current
directory.

After a lengthy discussion, and an even lengthier time to mull over the
problem and its best solution, and then more discussions, we eventually
decided to introduce support for the magic sequence `%(prefix)/`. If a
path starts with this, the remainder is interpreted as relative to the
detected (runtime) prefix. If built without runtime prefix support, Git
will simply interpolate the compiled-in prefix.

If a user _wants_ to specify a path starting with the magic sequence,
they can prefix the magic sequence with `./` and voilà, the path won't
be expanded.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-07-26 12:17:16 -07:00
Johannes Schindelin
a03b097d63 Use a better name for the function interpolating paths
It is not immediately clear what `expand_user_path()` means, so let's
rename it to `interpolate_path()`. This also opens the path for
interpolating more than just a home directory.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-07-26 12:17:16 -07:00
Johannes Schindelin
644e6b2c0f expand_user_path(): clarify the role of the real_home parameter
The `real_home` parameter only has an effect when expanding paths
starting with `~/`, not when expanding paths starting with `~<user>/`.
Let's make that clear.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-07-26 12:17:16 -07:00
Johannes Schindelin
789f6f226b expand_user_path(): remove stale part of the comment
In 395de250d9 (Expand ~ and ~user in core.excludesfile,
commit.template, 2009-11-17), the `user_path()` function was refactored
into the `expand_user_path()`. During that refactoring, the `buf`
parameter was lost, but the code comment above said function still talks
about it. Let's remove that stale part of the comment.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-07-26 12:17:16 -07:00
Jeff King
801ed010bf t0060: test ntfs/hfs-obscured dotfiles
We have tests that cover various filesystem-specific spellings of
".gitmodules", because we need to reliably identify that path for some
security checks. These are from dc2d9ba318 (is_{hfs,ntfs}_dotgitmodules:
add tests, 2018-05-12), with the actual code coming from e7cb0b4455
(is_ntfs_dotgit: match other .git files, 2018-05-11) and 0fc333ba20
(is_hfs_dotgit: match other .git files, 2018-05-02).

Those latter two commits also added similar matching functions for
.gitattributes and .gitignore. These ended up not being used in the
final series, and are currently dead code. But in preparation for them
being used in some fsck checks, let's make sure they actually work by
throwing a few basic tests at them. Likewise, let's cover .mailmap
(which does need matching code added).

I didn't bother with the whole battery of tests that we cover for
.gitmodules. These functions are all based on the same generic matcher,
so it's sufficient to test most of the corner cases just once.

Note that the ntfs magic prefix names in the tests come from the
algorithm described in e7cb0b4455 (and are different for each file).

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-05-04 11:52:02 +09:00
Elijah Newren
5291828df8 merge-ort: write $GIT_DIR/AUTO_MERGE whenever we hit a conflict
There are a variety of questions users might ask while resolving
conflicts:
  * What changes have been made since the previous (first) parent?
  * What changes are staged?
  * What is still unstaged? (or what is still conflicted?)
  * What changes did I make to resolve conflicts so far?
The first three of these have simple answers:
  * git diff HEAD
  * git diff --cached
  * git diff
There was no way to answer the final question previously.  Adding one
is trivial in merge-ort, since it works by creating a tree representing
what should be written to the working copy complete with conflict
markers.  Simply write that tree to .git/AUTO_MERGE, allowing users to
answer the fourth question with
  * git diff AUTO_MERGE

I avoided using a name like "MERGE_AUTO", because that would be
merge-specific (much like MERGE_HEAD, REBASE_HEAD, REVERT_HEAD,
CHERRY_PICK_HEAD) and I wanted a name that didn't change depending on
which type of operation the merge was part of.

Ensure that paths which clean out other temporary operation-specific
files (e.g. CHERRY_PICK_HEAD, MERGE_MSG, rebase-merge/ state directory)
also clean out this AUTO_MERGE file.

Signed-off-by: Elijah Newren <newren@gmail.com>
Reviewed-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-03-20 12:35:40 -07:00
Han-Wen Nienhuys
b8825ef233 sequencer: treat REVERT_HEAD as a pseudo ref
Signed-off-by: Han-Wen Nienhuys <hanwen@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-08-21 11:20:11 -07:00
Han-Wen Nienhuys
c8e4159efd sequencer: treat CHERRY_PICK_HEAD as a pseudo ref
Check for existence and delete CHERRY_PICK_HEAD through ref functions.
This will help cherry-pick work with alternate ref storage backends.

Signed-off-by: Han-Wen Nienhuys <hanwen@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-08-21 11:20:10 -07:00
Junio C Hamano
bf10200871 Merge branch 'dl/merge-autostash'
"git merge" learns the "--autostash" option.

* dl/merge-autostash: (22 commits)
  pull: pass --autostash to merge
  t5520: make test_pull_autostash() accept expect_parent_num
  merge: teach --autostash option
  sequencer: implement apply_autostash_oid()
  sequencer: implement save_autostash()
  sequencer: unlink autostash in apply_autostash()
  sequencer: extract perform_autostash() from rebase
  rebase: generify create_autostash()
  rebase: extract create_autostash()
  reset: extract reset_head() from rebase
  rebase: generify reset_head()
  rebase: use apply_autostash() from sequencer.c
  sequencer: rename stash_sha1 to stash_oid
  sequencer: make apply_autostash() accept a path
  rebase: use read_oneliner()
  sequencer: make read_oneliner() extern
  sequencer: configurably warn on non-existent files
  sequencer: make read_oneliner() accept flags
  sequencer: make file exists check more efficient
  sequencer: stop leaking buf
  ...
2020-04-29 16:15:27 -07:00
Denton Liu
a03b55530a merge: teach --autostash option
In rebase, one can pass the `--autostash` option to cause the worktree
to be automatically stashed before continuing with the rebase. This
option is missing in merge, however.

Implement the `--autostash` option and corresponding `merge.autoStash`
option in merge which stashes before merging and then pops after.

This option is useful when a developer has some local changes on a topic
branch but they realize that their work depends on another branch.
Previously, they had to run something like

	git fetch ...
	git stash push
	git merge FETCH_HEAD
	git stash pop

but now, that is reduced to

	git fetch ...
	git merge --autostash FETCH_HEAD

When an autostash is generated, it is automatically reapplied to the
worktree only in three explicit situations:

	1. An incomplete merge is commit using `git commit`.
	2. A merge completes successfully.
	3. A merge is aborted using `git merge --abort`.

In all other situations where the merge state is removed using
remove_merge_branch_state() such as aborting a merge via
`git reset --hard`, the autostash is saved into the stash reflog
instead keeping the worktree clean.

Helped-by: Phillip Wood <phillip.wood@dunelm.org.uk>
Suggested-by: Alban Gruin <alban.gruin@gmail.com>
Signed-off-by: Denton Liu <liu.denton@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-10 09:28:02 -07:00
Junio C Hamano
f8cb64e3d4 Merge branch 'bc/sha-256-part-1-of-4'
SHA-256 transition continues.

* bc/sha-256-part-1-of-4: (22 commits)
  fast-import: add options for rewriting submodules
  fast-import: add a generic function to iterate over marks
  fast-import: make find_marks work on any mark set
  fast-import: add helper function for inserting mark object entries
  fast-import: permit reading multiple marks files
  commit: use expected signature header for SHA-256
  worktree: allow repository version 1
  init-db: move writing repo version into a function
  builtin/init-db: add environment variable for new repo hash
  builtin/init-db: allow specifying hash algorithm on command line
  setup: allow check_repository_format to read repository format
  t/helper: make repository tests hash independent
  t/helper: initialize repository if necessary
  t/helper/test-dump-split-index: initialize git repository
  t6300: make hash algorithm independent
  t6300: abstract away SHA-1-specific constants
  t: use hash-specific lookup tables to define test constants
  repository: require a build flag to use SHA-256
  hex: add functions to parse hex object IDs in any algorithm
  hex: introduce parsing variants taking hash algorithms
  ...
2020-03-26 17:11:20 -07:00
Alexandr Miloslavskiy
3d7747e318 real_path: remove unsafe API
Returning a shared buffer invites very subtle bugs due to reentrancy or
multi-threading, as demonstrated by the previous patch.

There was an unfinished effort to abolish this [1].

Let's finally rid of `real_path()`, using `strbuf_realpath()` instead.

This patch uses a local `strbuf` for most places where `real_path()` was
previously called.

However, two places return the value of `real_path()` to the caller. For
them, a `static` local `strbuf` was added, effectively pushing the
problem one level higher:
    read_gitfile_gently()
    get_superproject_working_tree()

[1] https://lore.kernel.org/git/1480964316-99305-1-git-send-email-bmwill@google.com/

Signed-off-by: Alexandr Miloslavskiy <alexandr.miloslavskiy@syntevo.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-03-10 11:41:40 -07:00
Alexandr Miloslavskiy
0915a5b4cd set_git_dir: fix crash when used with real_path()
`real_path()` returns result from a shared buffer, inviting subtle
reentrance bugs. One of these bugs occur when invoked this way:
    set_git_dir(real_path(git_dir))

In this case, `real_path()` has reentrance:
    real_path
    read_gitfile_gently
    repo_set_gitdir
    setup_git_env
    set_git_dir_1
    set_git_dir

Later, `set_git_dir()` uses its now-dead parameter:
    !is_absolute_path(path)

Fix this by using a dedicated `strbuf` to hold `strbuf_realpath()`.

Signed-off-by: Alexandr Miloslavskiy <alexandr.miloslavskiy@syntevo.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-03-06 14:45:51 -08:00
brian m. carlson
cfe3917c85 setup: allow check_repository_format to read repository format
In some cases, we will want to not only check the repository format, but
extract the information that we've gained.  To do so, allow
check_repository_format to take a pointer to struct repository_format.
Allow passing NULL for this argument if we're not interested in the
information, and pass NULL for all existing callers.  A future patch
will make use of this information.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-02-24 09:33:27 -08:00
Jeff King
9734b74a8f normalize_path_copy(): document "dst" size expectations
We take a "dst" buffer to write into, but there's no matching "len"
parameter. The hidden assumption is that normalizing always makes things
smaller, so we're OK as long as "dst" is at least as big as "src". Let's
document that explicitly.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-01-30 13:45:58 -08:00
Junio C Hamano
7034cd094b Sync with Git 2.24.1 2019-12-09 22:17:55 -08:00
Johannes Schindelin
67af91c47a Sync with 2.23.1
* maint-2.23: (44 commits)
  Git 2.23.1
  Git 2.22.2
  Git 2.21.1
  mingw: sh arguments need quoting in more circumstances
  mingw: fix quoting of empty arguments for `sh`
  mingw: use MSYS2 quoting even when spawning shell scripts
  mingw: detect when MSYS2's sh is to be spawned more robustly
  t7415: drop v2.20.x-specific work-around
  Git 2.20.2
  t7415: adjust test for dubiously-nested submodule gitdirs for v2.20.x
  Git 2.19.3
  Git 2.18.2
  Git 2.17.3
  Git 2.16.6
  test-drop-caches: use `has_dos_drive_prefix()`
  Git 2.15.4
  Git 2.14.6
  mingw: handle `subst`-ed "DOS drives"
  mingw: refuse to access paths with trailing spaces or periods
  mingw: refuse to access paths with illegal characters
  ...
2019-12-06 16:31:39 +01:00
Johannes Schindelin
5421ddd8d0 Sync with 2.21.1
* maint-2.21: (42 commits)
  Git 2.21.1
  mingw: sh arguments need quoting in more circumstances
  mingw: fix quoting of empty arguments for `sh`
  mingw: use MSYS2 quoting even when spawning shell scripts
  mingw: detect when MSYS2's sh is to be spawned more robustly
  t7415: drop v2.20.x-specific work-around
  Git 2.20.2
  t7415: adjust test for dubiously-nested submodule gitdirs for v2.20.x
  Git 2.19.3
  Git 2.18.2
  Git 2.17.3
  Git 2.16.6
  test-drop-caches: use `has_dos_drive_prefix()`
  Git 2.15.4
  Git 2.14.6
  mingw: handle `subst`-ed "DOS drives"
  mingw: refuse to access paths with trailing spaces or periods
  mingw: refuse to access paths with illegal characters
  unpack-trees: let merged_entry() pass through do_add_entry()'s errors
  quote-stress-test: offer to test quoting arguments for MSYS2 sh
  ...
2019-12-06 16:31:23 +01:00
Johannes Schindelin
fc346cb292 Sync with 2.20.2
* maint-2.20: (36 commits)
  Git 2.20.2
  t7415: adjust test for dubiously-nested submodule gitdirs for v2.20.x
  Git 2.19.3
  Git 2.18.2
  Git 2.17.3
  Git 2.16.6
  test-drop-caches: use `has_dos_drive_prefix()`
  Git 2.15.4
  Git 2.14.6
  mingw: handle `subst`-ed "DOS drives"
  mingw: refuse to access paths with trailing spaces or periods
  mingw: refuse to access paths with illegal characters
  unpack-trees: let merged_entry() pass through do_add_entry()'s errors
  quote-stress-test: offer to test quoting arguments for MSYS2 sh
  t6130/t9350: prepare for stringent Win32 path validation
  quote-stress-test: allow skipping some trials
  quote-stress-test: accept arguments to test via the command-line
  tests: add a helper to stress test argument quoting
  mingw: fix quoting of arguments
  Disallow dubiously-nested submodule git directories
  ...
2019-12-06 16:31:12 +01:00
Johannes Schindelin
d851d94151 Sync with 2.19.3
* maint-2.19: (34 commits)
  Git 2.19.3
  Git 2.18.2
  Git 2.17.3
  Git 2.16.6
  test-drop-caches: use `has_dos_drive_prefix()`
  Git 2.15.4
  Git 2.14.6
  mingw: handle `subst`-ed "DOS drives"
  mingw: refuse to access paths with trailing spaces or periods
  mingw: refuse to access paths with illegal characters
  unpack-trees: let merged_entry() pass through do_add_entry()'s errors
  quote-stress-test: offer to test quoting arguments for MSYS2 sh
  t6130/t9350: prepare for stringent Win32 path validation
  quote-stress-test: allow skipping some trials
  quote-stress-test: accept arguments to test via the command-line
  tests: add a helper to stress test argument quoting
  mingw: fix quoting of arguments
  Disallow dubiously-nested submodule git directories
  protect_ntfs: turn on NTFS protection by default
  path: also guard `.gitmodules` against NTFS Alternate Data Streams
  ...
2019-12-06 16:30:49 +01:00
Johannes Schindelin
7c9fbda6e2 Sync with 2.18.2
* maint-2.18: (33 commits)
  Git 2.18.2
  Git 2.17.3
  Git 2.16.6
  test-drop-caches: use `has_dos_drive_prefix()`
  Git 2.15.4
  Git 2.14.6
  mingw: handle `subst`-ed "DOS drives"
  mingw: refuse to access paths with trailing spaces or periods
  mingw: refuse to access paths with illegal characters
  unpack-trees: let merged_entry() pass through do_add_entry()'s errors
  quote-stress-test: offer to test quoting arguments for MSYS2 sh
  t6130/t9350: prepare for stringent Win32 path validation
  quote-stress-test: allow skipping some trials
  quote-stress-test: accept arguments to test via the command-line
  tests: add a helper to stress test argument quoting
  mingw: fix quoting of arguments
  Disallow dubiously-nested submodule git directories
  protect_ntfs: turn on NTFS protection by default
  path: also guard `.gitmodules` against NTFS Alternate Data Streams
  is_ntfs_dotgit(): speed it up
  ...
2019-12-06 16:30:38 +01:00
Johannes Schindelin
14af7ed5a9 Sync with 2.17.3
* maint-2.17: (32 commits)
  Git 2.17.3
  Git 2.16.6
  test-drop-caches: use `has_dos_drive_prefix()`
  Git 2.15.4
  Git 2.14.6
  mingw: handle `subst`-ed "DOS drives"
  mingw: refuse to access paths with trailing spaces or periods
  mingw: refuse to access paths with illegal characters
  unpack-trees: let merged_entry() pass through do_add_entry()'s errors
  quote-stress-test: offer to test quoting arguments for MSYS2 sh
  t6130/t9350: prepare for stringent Win32 path validation
  quote-stress-test: allow skipping some trials
  quote-stress-test: accept arguments to test via the command-line
  tests: add a helper to stress test argument quoting
  mingw: fix quoting of arguments
  Disallow dubiously-nested submodule git directories
  protect_ntfs: turn on NTFS protection by default
  path: also guard `.gitmodules` against NTFS Alternate Data Streams
  is_ntfs_dotgit(): speed it up
  mingw: disallow backslash characters in tree objects' file names
  ...
2019-12-06 16:29:15 +01:00
Johannes Schindelin
d3ac8c3f27 Sync with 2.14.6
* maint-2.14: (28 commits)
  Git 2.14.6
  mingw: handle `subst`-ed "DOS drives"
  mingw: refuse to access paths with trailing spaces or periods
  mingw: refuse to access paths with illegal characters
  unpack-trees: let merged_entry() pass through do_add_entry()'s errors
  quote-stress-test: offer to test quoting arguments for MSYS2 sh
  t6130/t9350: prepare for stringent Win32 path validation
  quote-stress-test: allow skipping some trials
  quote-stress-test: accept arguments to test via the command-line
  tests: add a helper to stress test argument quoting
  mingw: fix quoting of arguments
  Disallow dubiously-nested submodule git directories
  protect_ntfs: turn on NTFS protection by default
  path: also guard `.gitmodules` against NTFS Alternate Data Streams
  is_ntfs_dotgit(): speed it up
  mingw: disallow backslash characters in tree objects' file names
  path: safeguard `.git` against NTFS Alternate Streams Accesses
  clone --recurse-submodules: prevent name squatting on Windows
  is_ntfs_dotgit(): only verify the leading segment
  test-path-utils: offer to run a protectNTFS/protectHFS benchmark
  ...
2019-12-06 16:26:55 +01:00
Johannes Schindelin
3a85dc7d53 is_ntfs_dotgit(): speed it up
Previously, this function was written without focusing on speed,
intending to make reviewing the code as easy as possible, to avoid any
bugs in this critical code.

Turns out: we can do much better on both accounts. With this patch, we
make it as fast as this developer can make it go:

- We avoid the call to `is_dir_sep()` and make all the character
  comparisons explicit.

- We avoid the cost of calling `strncasecmp()` and unroll the test for
  `.git` and `git~1`, not even using `tolower()` because it is faster to
  compare against two constant values.

- We look for `.git` and `.git~1` first thing, and return early if not
  found.

- We also avoid calling a separate function for detecting chains of
  spaces and periods.

Each of these improvements has a noticeable impact on the speed of
`is_ntfs_dotgit()`.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2019-12-05 15:36:51 +01:00
Johannes Schindelin
91bd46588e path: also guard .gitmodules against NTFS Alternate Data Streams
We just safe-guarded `.git` against NTFS Alternate Data Stream-related
attack vectors, and now it is time to do the same for `.gitmodules`.

Note: In the added regression test, we refrain from verifying all kinds
of variations between short names and NTFS Alternate Data Streams: as
the new code disallows _all_ Alternate Data Streams of `.gitmodules`, it
is enough to test one in order to know that all of them are guarded
against.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2019-12-05 15:36:51 +01:00
Johannes Schindelin
7c3745fc61 path: safeguard .git against NTFS Alternate Streams Accesses
Probably inspired by HFS' resource streams, NTFS supports "Alternate
Data Streams": by appending `:<stream-name>` to the file name,
information in addition to the file contents can be written and read,
information that is copied together with the file (unless copied to a
non-NTFS location).

These Alternate Data Streams are typically used for things like marking
an executable as having just been downloaded from the internet (and
hence not necessarily being trustworthy).

In addition to a stream name, a stream type can be appended, like so:
`:<stream-name>:<stream-type>`. Unless specified, the default stream
type is `$DATA` for files and `$INDEX_ALLOCATION` for directories. In
other words, `.git::$INDEX_ALLOCATION` is a valid way to reference the
`.git` directory!

In our work in Git v2.2.1 to protect Git on NTFS drives under
`core.protectNTFS`, we focused exclusively on NTFS short names, unaware
of the fact that NTFS Alternate Data Streams offer a similar attack
vector.

Let's fix this.

Seeing as it is better to be safe than sorry, we simply disallow paths
referring to *any* NTFS Alternate Data Stream of `.git`, not just
`::$INDEX_ALLOCATION`. This also simplifies the implementation.

This closes CVE-2019-1352.

Further reading about NTFS Alternate Data Streams:
https://docs.microsoft.com/en-us/openspecs/windows_protocols/ms-fscc/c54dec26-1551-4d3a-a0ea-4fa40f848eb3

Reported-by: Nicolas Joly <Nicolas.Joly@microsoft.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2019-12-05 15:36:50 +01:00
Johannes Schindelin
288a74bcd2 is_ntfs_dotgit(): only verify the leading segment
The config setting `core.protectNTFS` is specifically designed to work
not only on Windows, but anywhere, to allow for repositories hosted on,
say, Linux servers to be protected against NTFS-specific attack vectors.

As a consequence, `is_ntfs_dotgit()` manually splits backslash-separated
paths (but does not do the same for paths separated by forward slashes),
under the assumption that the backslash might not be a valid directory
separator on the _current_ Operating System.

However, the two callers, `verify_path()` and `fsck_tree()`, are
supposed to feed only individual path segments to the `is_ntfs_dotgit()`
function.

This causes a lot of duplicate scanning (and very inefficient scanning,
too, as the inner loop of `is_ntfs_dotgit()` was optimized for
readability rather than for speed.

Let's simplify the design of `is_ntfs_dotgit()` by putting the burden of
splitting the paths by backslashes as directory separators on the
callers of said function.

Consequently, the `verify_path()` function, which already splits the
path by directory separators, now treats backslashes as directory
separators _explicitly_ when `core.protectNTFS` is turned on, even on
platforms where the backslash is _not_ a directory separator.

Note that we have to repeat some code in `verify_path()`: if the
backslash is not a directory separator on the current Operating System,
we want to allow file names like `\`, but we _do_ want to disallow paths
that are clearly intended to cause harm when the repository is cloned on
Windows.

The `fsck_tree()` function (the other caller of `is_ntfs_dotgit()`) now
needs to look for backslashes in tree entries' names specifically when
`core.protectNTFS` is turned on. While it would be tempting to
completely disallow backslashes in that case (much like `fsck` reports
names containing forward slashes as "full paths"), this would be
overzealous: when `core.protectNTFS` is turned on in a non-Windows
setup, backslashes are perfectly valid characters in file names while we
_still_ want to disallow tree entries that are clearly designed to
exploit NTFS-specific behavior.

This simplification will make subsequent changes easier to implement,
such as turning `core.protectNTFS` on by default (not only on Windows)
or protecting against attack vectors involving NTFS Alternate Data
Streams.

Incidentally, this change allows for catching malicious repositories
that contain tree entries of the form `dir\.gitmodules` already on the
server side rather than only on the client side (and previously only on
Windows): in contrast to `is_ntfs_dotgit()`, the
`is_ntfs_dotgitmodules()` function already expects the caller to split
the paths by directory separators.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2019-12-05 15:36:50 +01:00
Johannes Schindelin
525e7fba78 path.c: document the purpose of is_ntfs_dotgit()
Previously, this function was completely undocumented. It is worth,
though, to explain what is going on, as it is not really obvious at all.

Suggested-by: Garima Singh <garima.singh@microsoft.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2019-12-04 13:20:05 +01:00
Junio C Hamano
a2b0451434 Merge branch 'js/git-path-head-dot-lock-fix'
"git rev-parse --git-path HEAD.lock" did not give the right path
when run in a secondary worktree.

* js/git-path-head-dot-lock-fix:
  git_path(): handle `.lock` files correctly
  t1400: wrap setup code in test case
2019-12-01 09:04:29 -08:00
Junio C Hamano
db806d7064 Merge branch 'sg/dir-trie-fixes'
Code clean-up and a bugfix in the logic used to tell worktree local
and repository global refs apart.

* sg/dir-trie-fixes:
  path.c: don't call the match function without value in trie_find()
  path.c: clarify two field names in 'struct common_dir'
  path.c: mark 'logs/HEAD' in 'common_list' as file
  path.c: clarify trie_find()'s in-code comment
  Documentation: mention more worktree-specific exceptions
2019-11-10 18:02:14 +09:00
Johannes Schindelin
76a53d640f git_path(): handle .lock files correctly
Ever since worktrees were introduced, the `git_path()` function _really_
needed to be called e.g. to get at the path to `logs/HEAD` (`HEAD` is
specific to the worktree, and therefore so is its reflog). However, the
wrong path is returned for `logs/HEAD.lock`.

This does not matter as long as the Git executable is doing the asking,
as the path for that `logs/HEAD.lock` file is constructed from
`git_path("logs/HEAD")` by appending the `.lock` suffix.

However, Git GUI just learned to use `--git-path` instead of appending
relative paths to what `git rev-parse --git-dir` returns (and as a
consequence not only using the correct hooks directory, but also using
the correct paths in worktrees other than the main one). While it does
not seem as if Git GUI in particular is asking for `logs/HEAD.lock`,
let's be safe rather than sorry.

Side note: Git GUI _does_ ask for `index.lock`, but that is already
resolved correctly, due to `update_common_dir()` preferring to leave
unknown paths in the (worktree-specific) git directory.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-10-29 12:38:36 +09:00
SZEDER Gábor
f45f88b2e4 path.c: don't call the match function without value in trie_find()
'logs/refs' is not a working tree-specific path, but since commit
b9317d55a3 (Make sure refs/rewritten/ is per-worktree, 2019-03-07)
'git rev-parse --git-path' has been returning a bogus path if a
trailing '/' is present:

  $ git -C WT/ rev-parse --git-path logs/refs --git-path logs/refs/
  /home/szeder/src/git/.git/logs/refs
  /home/szeder/src/git/.git/worktrees/WT/logs/refs/

We use a trie data structure to efficiently decide whether a path
belongs to the common dir or is working tree-specific.  As it happens
b9317d55a3 triggered a bug that is as old as the trie implementation
itself, added in 4e09cf2acf (path: optimize common dir checking,
2015-08-31).

  - According to the comment describing trie_find(), it should only
    call the given match function 'fn' for a "/-or-\0-terminated
    prefix of the key for which the trie contains a value".  This is
    not true: there are three places where trie_find() calls the match
    function, but one of them is missing the check for value's
    existence.

  - b9317d55a3 added two new keys to the trie: 'logs/refs/rewritten'
    and 'logs/refs/worktree', next to the already existing
    'logs/refs/bisect'.  This resulted in a trie node with the path
    'logs/refs/', which didn't exist before, and which doesn't have a
    value attached.  A query for 'logs/refs/' finds this node and then
    hits that one callsite of the match function which doesn't check
    for the value's existence, and thus invokes the match function
    with NULL as value.

  - When the match function check_common() is invoked with a NULL
    value, it returns 0, which indicates that the queried path doesn't
    belong to the common directory, ultimately resulting the bogus
    path shown above.

Add the missing condition to trie_find() so it will never invoke the
match function with a non-existing value.  check_common() will then no
longer have to check that it got a non-NULL value, so remove that
condition.

I believe that there are no other paths that could cause similar bogus
output.  AFAICT the only other key resulting in the match function
being called with a NULL value is 'co' (because of the keys 'common'
and 'config').  However, as they are not in a directory that belongs
to the common directory the resulting working tree-specific path is
expected.

Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-10-23 12:54:22 +09:00
SZEDER Gábor
c72fc40d09 path.c: clarify two field names in 'struct common_dir'
An array of 'struct common_dir' instances is used to specify whether
various paths in $GIT_DIR are specific to a worktree, or are common,
i.e. belong to main worktree.  The names of two fields in this
struct are somewhat confusing or ambigious:

  - The path is recorded in the struct's 'dirname' field, even though
    several entries are regular files e.g. 'gc.pid', 'packed-refs',
    etc.

    Rename this field to 'path' to reduce confusion.

  - The field 'exclude' tells whether the path is excluded...  from
    where?  Excluded from the common dir or from the worktree?  It
    means the former, but it's ambigious.

    Rename this field to 'is_common' to make it unambigious what it
    means.  This, however, means the exact opposite of what 'exclude'
    meant, so we have to negate the field's value in all entries as
    well.

The diff is best viewed with '--color-words'.

Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-10-23 12:53:51 +09:00
SZEDER Gábor
8a64881b44 path.c: mark 'logs/HEAD' in 'common_list' as file
'logs/HEAD', i.e. HEAD's reflog, is a file, but its entry in
'common_list' has the 'is_dir' bit set.

Unset that bit to make it consistent with what 'logs/HEAD' is supposed
to be.

This doesn't make a difference in behavior: check_common() is the only
function that looks at the 'is_dir' bit, and that function either
returns 0, or '!exclude', which for 'logs/HEAD' results in 0 as well.

Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-10-23 12:53:51 +09:00
SZEDER Gábor
7cb8c929d7 path.c: clarify trie_find()'s in-code comment
A fairly long comment describes trie_find()'s behavior and shows
examples, but it's slightly incomplete/inaccurate.  Update this
comment to specify how trie_find() handles a negative return value
from the given match function.

Furthermore, update the list of examples to include not only two but
three levels of path components.  This makes the examples slightly
more complicated, but it can illustrate the behavior in more corner
cases.

Finally, basically everything refers to the data stored for a key as
"value", with two confusing exceptions:

  - The type definition of the match function calls its corresponding
    parameter 'data'.
    Rename that parameter to 'value'.  (check_common(), the only
    function of this type already calls it 'value').

  - The table of examples above trie_find() has a "val from node"
    column, which has nothing to do with the value stored in the trie:
    it's a "prefix of the key for which the trie contains a value"
    that led to that node.
    Rename that column header to "prefix to node".

Note that neither the original nor the updated description and
examples correspond 100% to the current implementation, because the
implementation is a bit buggy, but the comment describes the desired
behavior.  The bug will be fixed in the last patch of this series.

Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-10-23 12:53:51 +09:00
brian m. carlson
ce17feb1b3 path: add a function to check for path suffix
We have a function to strip the path suffix from a commit, but we don't
have one to check for a path suffix. For a plain filename, we can use
basename, but that requires an allocation, since POSIX allows it to
modify its argument. Refactor strip_path_suffix into a helper function
and a new function, ends_with_path_components, to meet this need.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-08-26 10:36:13 -07:00
Junio C Hamano
917f2cd1c2 Merge branch 'nd/rewritten-ref-is-per-worktree'
"git rebase" uses the refs/rewritten/ hierarchy to store its
intermediate states, which inherently makes the hierarchy per
worktree, but it didn't quite work well.

* nd/rewritten-ref-is-per-worktree:
  Make sure refs/rewritten/ is per-worktree
  files-backend.c: reduce duplication in add_per_worktree_entries_to_dir()
  files-backend.c: factor out per-worktree code in loose_fill_ref_dir()
2019-04-10 02:14:23 +09:00
Nguyễn Thái Ngọc Duy
b9317d55a3 Make sure refs/rewritten/ is per-worktree
a9be29c981 (sequencer: make refs generated by the `label` command
worktree-local, 2018-04-25) adds refs/rewritten/ as per-worktree
reference space. Unfortunately (my bad) there are a couple places that
need update to make sure it's really per-worktree.

 - add_per_worktree_entries_to_dir() is updated to make sure ref listing
   look at per-worktree refs/rewritten/ instead of per-repo one [1]

 - common_list[] is updated so that git_path() returns the correct
   location. This includes "rev-parse --git-path".

This mess is created by me. I started trying to fix it with the
introduction of refs/worktree, where all refs will be per-worktree
without special treatments. Unfortunate refs/rewritten came before
refs/worktree so this is all we can do.

This also fixes logs/refs/worktree not being per-worktree.

[1] note that ref listing still works sometimes. For example, if you
    have .git/worktrees/foo/refs/rewritten/bar AND the directory
    .git/worktrees/refs/rewritten, refs/rewritten/bar will show up.
    add_per_worktree_entries_to_dir() is only needed when the directory
    .git/worktrees/refs/rewritten is missing.

Reported-by: Phillip Wood <phillip.wood123@gmail.com>
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-03-08 11:57:47 +09:00
Junio C Hamano
3b2f8a02fa Merge branch 'jk/loose-object-cache'
Code clean-up with optimization for the codepath that checks
(non-)existence of loose objects.

* jk/loose-object-cache:
  odb_load_loose_cache: fix strbuf leak
  fetch-pack: drop custom loose object cache
  sha1-file: use loose object cache for quick existence check
  object-store: provide helpers for loose_objects_cache
  sha1-file: use an object_directory for the main object dir
  handle alternates paths the same as the main object dir
  sha1_file_name(): overwrite buffer instead of appending
  rename "alternate_object_database" to "object_directory"
  submodule--helper: prefer strip_suffix() to ends_with()
  fsck: do not reuse child_process structs
2019-01-04 13:33:32 -08:00
Junio C Hamano
85eb0f162c Merge branch 'tb/char-may-be-unsigned' into maint
Build portability fix.

* tb/char-may-be-unsigned:
  path.c: char is not (always) signed
2018-11-21 22:58:09 +09:00
Junio C Hamano
e146cc97be Merge branch 'nd/per-worktree-ref-iteration'
The code to traverse objects for reachability, used to decide what
objects are unreferenced and expendable, have been taught to also
consider per-worktree refs of other worktrees as starting points to
prevent data loss.

* nd/per-worktree-ref-iteration:
  git-worktree.txt: correct linkgit command name
  reflog expire: cover reflog from all worktrees
  fsck: check HEAD and reflog from other worktrees
  fsck: move fsck_head_link() to get_default_heads() to avoid some globals
  revision.c: better error reporting on ref from different worktrees
  revision.c: correct a parameter name
  refs: new ref types to make per-worktree refs visible to all worktrees
  Add a place for (not) sharing stuff between worktrees
  refs.c: indent with tabs, not spaces
2018-11-13 22:37:26 +09:00
Jeff King
f0eaf63819 sha1-file: use an object_directory for the main object dir
Our handling of alternate object directories is needlessly different
from the main object directory. As a result, many places in the code
basically look like this:

  do_something(r->objects->objdir);

  for (odb = r->objects->alt_odb_list; odb; odb = odb->next)
        do_something(odb->path);

That gets annoying when do_something() is non-trivial, and we've
resorted to gross hacks like creating fake alternates (see
find_short_object_filename()).

Instead, let's give each raw_object_store a unified list of
object_directory structs. The first will be the main store, and
everything after is an alternate. Very few callers even care about the
distinction, and can just loop over the whole list (and those who care
can just treat the first element differently).

A few observations:

  - we don't need r->objects->objectdir anymore, and can just
    mechanically convert that to r->objects->odb->path

  - object_directory's path field needs to become a real pointer rather
    than a FLEX_ARRAY, in order to fill it with expand_base_dir()

  - we'll call prepare_alt_odb() earlier in many functions (i.e.,
    outside of the loop). This may result in us calling it even when our
    function would be satisfied looking only at the main odb.

    But this doesn't matter in practice. It's not a very expensive
    operation in the first place, and in the majority of cases it will
    be a noop. We call it already (and cache its results) in
    prepare_packed_git(), and we'll generally check packs before loose
    objects. So essentially every program is going to call it
    immediately once per program.

    Arguably we should just prepare_alt_odb() immediately upon setting
    up the repository's object directory, which would save us sprinkling
    calls throughout the code base (and forgetting to do so has been a
    source of subtle bugs in the past). But I've stopped short of that
    here, since there are already a lot of other moving parts in this
    patch.

  - Most call sites just get shorter. The check_and_freshen() functions
    are an exception, because they have entry points to handle local and
    nonlocal directories separately.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-11-13 14:22:03 +09:00
Junio C Hamano
1f8e7dc4da Merge branch 'tb/char-may-be-unsigned'
Build portability fix.

* tb/char-may-be-unsigned:
  path.c: char is not (always) signed
2018-11-06 15:50:22 +09:00
Torsten Bögershausen
3063477445 path.c: char is not (always) signed
If a "char" in C is signed or unsigned is not specified, because it is
out of tradition "implementation dependent".
Therefore constructs like "if (name[i] < 0)" are not portable,
use "if (name[i] & 0x80)" instead.

Detected by "gcc (Raspbian 6.3.0-18+rpi1+deb9u1) 6.3.0 20170516" when
setting
DEVELOPER = 1
DEVOPTS = extra-all

Signed-off-by: Torsten Bögershausen <tboegi@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-10-26 11:20:01 +09:00
Nguyễn Thái Ngọc Duy
8aff1a9ca5 Add a place for (not) sharing stuff between worktrees
When multiple worktrees are used, we need rules to determine if
something belongs to one worktree or all of them. Instead of keeping
adding rules when new stuff comes (*), have a generic rule:

- Inside $GIT_DIR, which is per-worktree by default, add
  $GIT_DIR/common which is always shared. New features that want to
  share stuff should put stuff under this directory.

- Inside refs/, which is shared by default except refs/bisect, add
  refs/worktree/ which is per-worktree. We may eventually move
  refs/bisect to this new location and remove the exception in refs
  code.

(*) And it may also include stuff from external commands which will
    have no way to modify common/per-worktree rules.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-10-07 08:21:18 +09:00
Junio C Hamano
00624d608c Merge branch 'sb/object-store-grafts'
The conversion to pass "the_repository" and then "a_repository"
throughout the object access API continues.

* sb/object-store-grafts:
  commit: allow lookup_commit_graft to handle arbitrary repositories
  commit: allow prepare_commit_graft to handle arbitrary repositories
  shallow: migrate shallow information into the object parser
  path.c: migrate global git_path_* to take a repository argument
  cache: convert get_graft_file to handle arbitrary repositories
  commit: convert read_graft_file to handle arbitrary repositories
  commit: convert register_commit_graft to handle arbitrary repositories
  commit: convert commit_graft_pos() to handle arbitrary repositories
  shallow: add repository argument to is_repository_shallow
  shallow: add repository argument to check_shallow_file_for_update
  shallow: add repository argument to register_shallow
  shallow: add repository argument to set_alternate_shallow_file
  commit: add repository argument to lookup_commit_graft
  commit: add repository argument to prepare_commit_graft
  commit: add repository argument to read_graft_file
  commit: add repository argument to register_commit_graft
  commit: add repository argument to commit_graft_pos
  object: move grafts to object parser
  object-store: move object access functions to object-store.h
2018-07-18 12:20:28 -07:00
Junio C Hamano
7913f53b56 Sync with Git 2.17.1
* maint: (25 commits)
  Git 2.17.1
  Git 2.16.4
  Git 2.15.2
  Git 2.14.4
  Git 2.13.7
  fsck: complain when .gitmodules is a symlink
  index-pack: check .gitmodules files with --strict
  unpack-objects: call fsck_finish() after fscking objects
  fsck: call fsck_finish() after fscking objects
  fsck: check .gitmodules content
  fsck: handle promisor objects in .gitmodules check
  fsck: detect gitmodules files
  fsck: actually fsck blob data
  fsck: simplify ".git" check
  index-pack: make fsck error message more specific
  verify_path: disallow symlinks in .gitmodules
  update-index: stat updated files earlier
  verify_dotfile: mention case-insensitivity in comment
  verify_path: drop clever fallthrough
  skip_prefix: add case-insensitive variant
  ...
2018-05-29 17:10:05 +09:00
Junio C Hamano
9e0f06d55d Sync with Git 2.14.4
* maint-2.14:
  Git 2.14.4
  Git 2.13.7
  verify_path: disallow symlinks in .gitmodules
  update-index: stat updated files earlier
  verify_dotfile: mention case-insensitivity in comment
  verify_path: drop clever fallthrough
  skip_prefix: add case-insensitive variant
  is_{hfs,ntfs}_dotgitmodules: add tests
  is_ntfs_dotgit: match other .git files
  is_hfs_dotgit: match other .git files
  is_ntfs_dotgit: use a size_t for traversing string
  submodule-config: verify submodule names as paths
2018-05-22 14:15:14 +09:00
Junio C Hamano
7b01c71b64 Sync with Git 2.13.7
* maint-2.13:
  Git 2.13.7
  verify_path: disallow symlinks in .gitmodules
  update-index: stat updated files earlier
  verify_dotfile: mention case-insensitivity in comment
  verify_path: drop clever fallthrough
  skip_prefix: add case-insensitive variant
  is_{hfs,ntfs}_dotgitmodules: add tests
  is_ntfs_dotgit: match other .git files
  is_hfs_dotgit: match other .git files
  is_ntfs_dotgit: use a size_t for traversing string
  submodule-config: verify submodule names as paths
2018-05-22 14:10:49 +09:00
Johannes Schindelin
e7cb0b4455 is_ntfs_dotgit: match other .git files
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>
2018-05-21 23:50:11 -04:00