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2019-12-06t7415: adjust test for dubiously-nested submodule gitdirs for v2.20.xLibravatar Johannes Schindelin1-1/+1
In v2.20.x, Git clones submodules recursively by first creating the submodules' gitdirs and _then_ "updating" the submodules. This can lead to the situation where the clone path is taken because the directory (while it exists already) is not a git directory, but then the clone fails because that gitdir is unexpectedly already a directory. This _also_ works around the vulnerability that was fixed in "Disallow dubiously-nested submodule git directories", but it produces a different error message than the one expected by the test case, therefore we adjust the test case accordingly. Note: as the two submodules "race each other", there are actually two possible error messages, therefore we have to teach the test case to expect _two_ possible (and good) outcomes in addition to the one it expected before. Note: this workaround is only necessary for the v2.20.x release train; The behavior changed again in v2.21.x so that the original test case's expectations are met again. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2019-12-06Sync with 2.19.3Libravatar Johannes Schindelin13-28/+445
* 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 ...
2019-12-06Sync with 2.18.2Libravatar Johannes Schindelin13-28/+445
* 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 ...
2019-12-06Sync with 2.17.3Libravatar Johannes Schindelin13-29/+446
* 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 ...
2019-12-06fsck: reject submodule.update = !command in .gitmodulesLibravatar Jonathan Nieder1-0/+14
This allows hosting providers to detect whether they are being used to attack users using malicious 'update = !command' settings in .gitmodules. Since ac1fbbda2013 (submodule: do not copy unknown update mode from .gitmodules, 2013-12-02), in normal cases such settings have been treated as 'update = none', so forbidding them should not produce any collateral damage to legitimate uses. A quick search does not reveal any repositories making use of this construct, either. Reported-by: Joern Schneeweisz <jschneeweisz@gitlab.com> Signed-off-by: Jonathan Nieder <jrnieder@gmail.com> Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2019-12-06Sync with 2.16.6Libravatar Johannes Schindelin13-29/+432
* maint-2.16: (31 commits) 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 path: safeguard `.git` against NTFS Alternate Streams Accesses ...
2019-12-06test-drop-caches: use `has_dos_drive_prefix()`Libravatar Johannes Schindelin1-5/+8
This is a companion patch to 'mingw: handle `subst`-ed "DOS drives"': use the DOS drive prefix handling that is already provided by `compat/mingw.c` (and which just learned to handle non-alphabetical "drive letters"). Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2019-12-06Sync with 2.15.4Libravatar Johannes Schindelin12-24/+424
* maint-2.15: (29 commits) 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 path: safeguard `.git` against NTFS Alternate Streams Accesses clone --recurse-submodules: prevent name squatting on Windows is_ntfs_dotgit(): only verify the leading segment ...
2019-12-06submodule: reject submodule.update = !command in .gitmodulesLibravatar Jonathan Nieder1-6/+8
Since ac1fbbda2013 (submodule: do not copy unknown update mode from .gitmodules, 2013-12-02), Git has been careful to avoid copying [submodule "foo"] update = !run an arbitrary scary command from .gitmodules to a repository's local config, copying in the setting 'update = none' instead. The gitmodules(5) manpage documents the intention: The !command form is intentionally ignored here for security reasons Unfortunately, starting with v2.20.0-rc0 (which integrated ee69b2a9 (submodule--helper: introduce new update-module-mode helper, 2018-08-13, first released in v2.20.0-rc0)), there are scenarios where we *don't* ignore it: if the config store contains no submodule.foo.update setting, the submodule-config API falls back to reading .gitmodules and the repository-supplied !command gets run after all. This was part of a general change over time in submodule support to read more directly from .gitmodules, since unlike .git/config it allows a project to change values between branches and over time (while still allowing .git/config to override things). But it was never intended to apply to this kind of dangerous configuration. The behavior change was not advertised in ee69b2a9's commit message and was missed in review. Let's take the opportunity to make the protection more robust, even in Git versions that are technically not affected: instead of quietly converting 'update = !command' to 'update = none', noisily treat it as an error. Allowing the setting but treating it as meaning something else was just confusing; users are better served by seeing the error sooner. Forbidding the construct makes the semantics simpler and means we can check for it in fsck (in a separate patch). As a result, the submodule-config API cannot read this value from .gitmodules under any circumstance, and we can declare with confidence For security reasons, the '!command' form is not accepted here. Reported-by: Joern Schneeweisz <jschneeweisz@gitlab.com> Signed-off-by: Jonathan Nieder <jrnieder@gmail.com> Signed-off-by: Johannes Schindelin <Johannes.Schindelin@gmx.de>
2019-12-06Sync with 2.14.6Libravatar Johannes Schindelin11-18/+416
* 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 ...
2019-12-05Merge branch 'win32-accommodate-funny-drive-names'Libravatar Johannes Schindelin1-1/+12
While the only permitted drive letters for physical drives on Windows are letters of the US-English alphabet, this restriction does not apply to virtual drives assigned via `subst <letter>: <path>`. To prevent targeted attacks against systems where "funny" drive letters such as `1` or `!` are assigned, let's handle them as regular drive letters on Windows. This fixes CVE-2019-1351. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2019-12-05Merge branch 'win32-filenames-cannot-have-trailing-spaces-or-periods'Libravatar Johannes Schindelin6-2/+51
On Windows, filenames cannot have trailing spaces or periods, when opening such paths, they are stripped automatically. Read: you can open the file `README` via the file name `README . . .`. This ambiguity can be used in combination with other security bugs to cause e.g. remote code execution during recursive clones. This patch series fixes that. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2019-12-05mingw: handle `subst`-ed "DOS drives"Libravatar Johannes Schindelin1-0/+9
Over a decade ago, in 25fe217b86c (Windows: Treat Windows style path names., 2008-03-05), Git was taught to handle absolute Windows paths, i.e. paths that start with a drive letter and a colon. Unbeknownst to us, while drive letters of physical drives are limited to letters of the English alphabet, there is a way to assign virtual drive letters to arbitrary directories, via the `subst` command, which is _not_ limited to English letters. It is therefore possible to have absolute Windows paths of the form `1:\what\the\hex.txt`. Even "better": pretty much arbitrary Unicode letters can also be used, e.g. `ä:\tschibät.sch`. While it can be sensibly argued that users who set up such funny drive letters really seek adverse consequences, the Windows Operating System is known to be a platform where many users are at the mercy of administrators who have their very own idea of what constitutes a reasonable setup. Therefore, let's just make sure that such funny paths are still considered absolute paths by Git, on Windows. In addition to Unicode characters, pretty much any character is a valid drive letter, as far as `subst` is concerned, even `:` and `"` or even a space character. While it is probably the opposite of smart to use them, let's safeguard `is_dos_drive_prefix()` against all of them. Note: `[::1]:repo` is a valid URL, but not a valid path on Windows. As `[` is now considered a valid drive letter, we need to be very careful to avoid misinterpreting such a string as valid local path in `url_is_local_not_ssh()`. To do that, we use the just-introduced function `is_valid_path()` (which will label the string as invalid file name because of the colon characters). This fixes CVE-2019-1351. Reported-by: Nicolas Joly <Nicolas.Joly@microsoft.com> Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2019-12-05mingw: refuse to access paths with trailing spaces or periodsLibravatar Johannes Schindelin4-1/+49
When creating a directory on Windows whose path ends in a space or a period (or chains thereof), the Win32 API "helpfully" trims those. For example, `mkdir("abc ");` will return success, but actually create a directory called `abc` instead. This stems back to the DOS days, when all file names had exactly 8 characters plus exactly 3 characters for the file extension, and the only way to have shorter names was by padding with spaces. Sadly, this "helpful" behavior is a bit inconsistent: after a successful `mkdir("abc ");`, a `mkdir("abc /def")` will actually _fail_ (because the directory `abc ` does not actually exist). Even if it would work, we now have a serious problem because a Git repository could contain directories `abc` and `abc `, and on Windows, they would be "merged" unintentionally. As these paths are illegal on Windows, anyway, let's disallow any accesses to such paths on that Operating System. For practical reasons, this behavior is still guarded by the config setting `core.protectNTFS`: it is possible (and at least two regression tests make use of it) to create commits without involving the worktree. In such a scenario, it is of course possible -- even on Windows -- to create such file names. Among other consequences, this patch disallows submodules' paths to end in spaces on Windows (which would formerly have confused Git enough to try to write into incorrect paths, anyway). While this patch does not fix a vulnerability on its own, it prevents an attack vector that was exploited in demonstrations of a number of recently-fixed security bugs. The regression test added to `t/t7417-submodule-path-url.sh` reflects that attack vector. Note that we have to adjust the test case "prevent git~1 squatting on Windows" in `t/t7415-submodule-names.sh` because of a very subtle issue. It tries to clone two submodules whose names differ only in a trailing period character, and as a consequence their git directories differ in the same way. Previously, when Git tried to clone the second submodule, it thought that the git directory already existed (because on Windows, when you create a directory with the name `b.` it actually creates `b`), but with this patch, the first submodule's clone will fail because of the illegal name of the git directory. Therefore, when cloning the second submodule, Git will take a different code path: a fresh clone (without an existing git directory). Both code paths fail to clone the second submodule, both because the the corresponding worktree directory exists and is not empty, but the error messages are worded differently. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2019-12-05quote-stress-test: offer to test quoting arguments for MSYS2 shLibravatar Johannes Schindelin1-3/+10
It is unfortunate that we need to quote arguments differently on Windows, depending whether we build a command-line for MSYS2's `sh` or for other Windows executables. We already have a test helper to verify the latter, with this patch we can also verify the former. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2019-12-05mingw: refuse to access paths with illegal charactersLibravatar Johannes Schindelin1-1/+3
Certain characters are not admissible in file names on Windows, even if Cygwin/MSYS2 (and therefore, Git for Windows' Bash) pretend that they are, e.g. `:`, `<`, `>`, etc Let's disallow those characters explicitly in Windows builds of Git. Note: just like trailing spaces or periods, it _is_ possible on Windows to create commits adding files with such illegal characters, as long as the operation leaves the worktree untouched. To allow for that, we continue to guard `is_valid_win32_path()` behind the config setting `core.protectNTFS`, so that users _can_ continue to do that, as long as they turn the protections off via that config setting. Among other problems, this prevents Git from trying to write to an "NTFS Alternate Data Stream" (which refers to metadata stored alongside a file, under a special name: "<filename>:<stream-name>"). This fix therefore also prevents an attack vector that was exploited in demonstrations of a number of recently-fixed security bugs. Further reading on illegal characters in Win32 filenames: https://docs.microsoft.com/en-us/windows/win32/fileio/naming-a-file Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2019-12-05quote-stress-test: allow skipping some trialsLibravatar Johannes Schindelin1-1/+5
When the, say, 93rd trial run fails, it is a good idea to have a way to skip the first 92 trials and dig directly into the 93rd in a debugger. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2019-12-05t6130/t9350: prepare for stringent Win32 path validationLibravatar Johannes Schindelin2-1/+2
On Windows, file names cannot contain asterisks nor newline characters. In an upcoming commit, we will make this limitation explicit, disallowing even the creation of commits that introduce such file names. However, in the test scripts touched by this patch, we _know_ that those paths won't be checked out, so we _want_ to allow such file names. Happily, the stringent path validation will be guarded via the `core.protectNTFS` flag, so all we need to do is to force that flag off temporarily. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2019-12-05quote-stress-test: accept arguments to test via the command-lineLibravatar Johannes Schindelin1-13/+22
When the stress test reported a problem with quoting certain arguments, it is helpful to have a facility to play with those arguments in order to find out whether variations of those arguments are affected, too. Let's allow `test-run-command quote-stress-test -- <args>` to be used for that purpose. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2019-12-05tests: add a helper to stress test argument quotingLibravatar Garima Singh1-2/+116
On Windows, we have to do all the command-line argument quoting ourselves. Worse: we have to have two versions of said quoting, one for MSYS2 programs (which have their own dequoting rules) and the rest. We care mostly about the rest, and to make sure that that works, let's have a stress test that comes up with all kinds of awkward arguments, verifying that a spawned sub-process receives those unharmed. Signed-off-by: Garima Singh <garima.singh@microsoft.com> Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2019-12-05mingw: fix quoting of argumentsLibravatar Johannes Schindelin1-0/+14
We need to be careful to follow proper quoting rules. For example, if an argument contains spaces, we have to quote them. Double-quotes need to be escaped. Backslashes need to be escaped, but only if they are followed by a double-quote character. We need to be _extra_ careful to consider the case where an argument ends in a backslash _and_ needs to be quoted: in this case, we append a double-quote character, i.e. the backslash now has to be escaped! The current code, however, fails to recognize that, and therefore can turn an argument that ends in a single backslash into a quoted argument that now ends in an escaped double-quote character. This allows subsequent command-line parameters to be split and part of them being mistaken for command-line options, e.g. through a maliciously-crafted submodule URL during a recursive clone. Technically, we would not need to quote _all_ arguments which end in a backslash _unless_ the argument needs to be quoted anyway. For example, `test\` would not need to be quoted, while `test \` would need to be. To keep the code simple, however, and therefore easier to reason about and ensure its correctness, we now _always_ quote an argument that ends in a backslash. This addresses CVE-2019-1350. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2019-12-05Disallow dubiously-nested submodule git directoriesLibravatar Johannes Schindelin1-0/+23
Currently it is technically possible to let a submodule's git directory point right into the git dir of a sibling submodule. Example: the git directories of two submodules with the names `hippo` and `hippo/hooks` would be `.git/modules/hippo/` and `.git/modules/hippo/hooks/`, respectively, but the latter is already intended to house the former's hooks. In most cases, this is just confusing, but there is also a (quite contrived) attack vector where Git can be fooled into mistaking remote content for file contents it wrote itself during a recursive clone. Let's plug this bug. To do so, we introduce the new function `validate_submodule_git_dir()` which simply verifies that no git dir exists for any leading directories of the submodule name (if there are any). Note: this patch specifically continues to allow sibling modules names of the form `core/lib`, `core/doc`, etc, as long as `core` is not a submodule name. This fixes CVE-2019-1387. Reported-by: Nicolas Joly <Nicolas.Joly@microsoft.com> Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2019-12-05path: also guard `.gitmodules` against NTFS Alternate Data StreamsLibravatar Johannes Schindelin1-1/+6
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>
2019-12-05path: safeguard `.git` against NTFS Alternate Streams AccessesLibravatar Johannes Schindelin1-0/+1
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>
2019-12-05test-path-utils: offer to run a protectNTFS/protectHFS benchmarkLibravatar Garima Singh1-0/+96
In preparation to flipping the default on `core.protectNTFS`, let's have some way to measure the speed impact of this config setting reliably (and for comparison, the `core.protectHFS` config setting). For now, this is a manual performance benchmark: ./t/helper/test-path-utils protect_ntfs_hfs [arguments...] where the arguments are an optional number of file names to test with, optionally followed by minimum and maximum length of the random file names. The default values are one million, 3 and 20, respectively. Just like `sqrti()` in `bisect.c`, we introduce a very simple function to approximation the square root of a given value, in order to avoid having to introduce the first user of `<math.h>` in Git's source code. Note: this is _not_ implemented as a Unix shell script in t/perf/ because we really care about _very_ precise timings here, and Unix shell scripts are simply unsuited for precise and consistent benchmarking. Signed-off-by: Garima Singh <garima.singh@microsoft.com> Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2019-12-04mingw: disallow backslash characters in tree objects' file namesLibravatar Johannes Schindelin3-3/+7
The backslash character is not a valid part of a file name on Windows. Hence it is dangerous to allow writing files that were unpacked from tree objects, when the stored file name contains a backslash character: it will be misinterpreted as directory separator. This not only causes ambiguity when a tree contains a blob `a\b` and a tree `a` that contains a blob `b`, but it also can be used as part of an attack vector to side-step the careful protections against writing into the `.git/` directory during a clone of a maliciously-crafted repository. Let's prevent that, addressing CVE-2019-1354. Note: we guard against backslash characters in tree objects' file names _only_ on Windows (because on other platforms, even on those where NTFS volumes can be mounted, the backslash character is _not_ a directory separator), and _only_ when `core.protectNTFS = true` (because users might need to generate tree objects for other platforms, of course without touching the worktree, e.g. using `git update-index --cacheinfo`). Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2019-12-04clone --recurse-submodules: prevent name squatting on WindowsLibravatar Johannes Schindelin1-0/+31
In addition to preventing `.git` from being tracked by Git, on Windows we also have to prevent `git~1` from being tracked, as the default NTFS short name (also known as the "8.3 filename") for the file name `.git` is `git~1`, otherwise it would be possible for malicious repositories to write directly into the `.git/` directory, e.g. a `post-checkout` hook that would then be executed _during_ a recursive clone. When we implemented appropriate protections in 2b4c6efc821 (read-cache: optionally disallow NTFS .git variants, 2014-12-16), we had analyzed carefully that the `.git` directory or file would be guaranteed to be the first directory entry to be written. Otherwise it would be possible e.g. for a file named `..git` to be assigned the short name `git~1` and subsequently, the short name generated for `.git` would be `git~2`. Or `git~3`. Or even `~9999999` (for a detailed explanation of the lengths we have to go to protect `.gitmodules`, see the commit message of e7cb0b4455c (is_ntfs_dotgit: match other .git files, 2018-05-11)). However, by exploiting two issues (that will be addressed in a related patch series close by), it is currently possible to clone a submodule into a non-empty directory: - On Windows, file names cannot end in a space or a period (for historical reasons: the period separating the base name from the file extension was not actually written to disk, and the base name/file extension was space-padded to the full 8/3 characters, respectively). Helpfully, when creating a directory under the name, say, `sub.`, that trailing period is trimmed automatically and the actual name on disk is `sub`. This means that while Git thinks that the submodule names `sub` and `sub.` are different, they both access `.git/modules/sub/`. - While the backslash character is a valid file name character on Linux, it is not so on Windows. As Git tries to be cross-platform, it therefore allows backslash characters in the file names stored in tree objects. Which means that it is totally possible that a submodule `c` sits next to a file `c\..git`, and on Windows, during recursive clone a file called `..git` will be written into `c/`, of course _before_ the submodule is cloned. Note that the actual exploit is not quite as simple as having a submodule `c` next to a file `c\..git`, as we have to make sure that the directory `.git/modules/b` already exists when the submodule is checked out, otherwise a different code path is taken in `module_clone()` that does _not_ allow a non-empty submodule directory to exist already. Even if we will address both issues nearby (the next commit will disallow backslash characters in tree entries' file names on Windows, and another patch will disallow creating directories/files with trailing spaces or periods), it is a wise idea to defend in depth against this sort of attack vector: when submodules are cloned recursively, we now _require_ the directory to be empty, addressing CVE-2019-1349. Note: the code path we patch is shared with the code path of `git submodule update --init`, which must not expect, in general, that the directory is empty. Hence we have to introduce the new option `--force-init` and hand it all the way down from `git submodule` to the actual `git submodule--helper` process that performs the initial clone. Reported-by: Nicolas Joly <Nicolas.Joly@microsoft.com> Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2019-12-04fast-import: disallow "feature import-marks" by defaultLibravatar Jeff King1-5/+17
As with export-marks in the previous commit, import-marks can access the filesystem. This is significantly less dangerous than export-marks because it only involves reading from arbitrary paths, rather than writing them. However, it could still be surprising and have security implications (e.g., exfiltrating data from a service that accepts fast-import streams). Let's lump it (and its "if-exists" counterpart) in with export-marks, and enable the in-stream version only if --allow-unsafe-features is set. Signed-off-by: Jeff King <peff@peff.net>
2019-12-04fast-import: disallow "feature export-marks" by defaultLibravatar Jeff King1-8/+15
The fast-import stream command "feature export-marks=<path>" lets the stream write marks to an arbitrary path. This may be surprising if you are running fast-import against an untrusted input (which otherwise cannot do anything except update Git objects and refs). Let's disallow the use of this feature by default, and provide a command-line option to re-enable it (you can always just use the command-line --export-marks as well, but the in-stream version provides an easy way for exporters to control the process). This is a backwards-incompatible change, since the default is flipping to the new, safer behavior. However, since the main users of the in-stream versions would be import/export-based remote helpers, and since we trust remote helpers already (which are already running arbitrary code), we'll pass the new option by default when reading a remote helper's stream. This should minimize the impact. Note that the implementation isn't totally simple, as we have to work around the fact that fast-import doesn't parse its command-line options until after it has read any "feature" lines from the stream. This is how it lets command-line options override in-stream. But in our case, it's important to parse the new --allow-unsafe-features first. There are three options for resolving this: 1. Do a separate "early" pass over the options. This is easy for us to do because there are no command-line options that allow the "unstuck" form (so there's no chance of us mistaking an argument for an option), though it does introduce a risk of incorrect parsing later (e.g,. if we convert to parse-options). 2. Move the option parsing phase back to the start of the program, but teach the stream-reading code never to override an existing value. This is tricky, because stream "feature" lines override each other (meaning we'd have to start tracking the source for every option). 3. Accept that we might parse a "feature export-marks" line that is forbidden, as long we don't _act_ on it until after we've parsed the command line options. This would, in fact, work with the current code, but only because the previous patch fixed the export-marks parser to avoid touching the filesystem. So while it works, it does carry risk of somebody getting it wrong in the future in a rather subtle and unsafe way. I've gone with option (1) here as simple, safe, and unlikely to cause regressions. This fixes CVE-2019-1348. Signed-off-by: Jeff King <peff@peff.net>
2019-12-04fast-import: delay creating leading directories for export-marksLibravatar Jeff King1-2/+11
When we parse the --export-marks option, we don't immediately open the file, but we do create any leading directories. This can be especially confusing when a command-line option overrides an in-stream one, in which case we'd create the leading directory for the in-stream file, even though we never actually write the file. Let's instead create the directories just before opening the file, which means we'll create only useful directories. Note that this could change the handling of relative paths if we chdir() in between, but we don't actually do so; the only permanent chdir is from setup_git_directory() which runs before either code path (potentially we should take the pre-setup dir into account to avoid surprising the user, but that's an orthogonal change). The test just adapts the existing "override" test to use paths with leading directories. This checks both that the correct directory is created (which worked before but was not tested), and that the overridden one is not (our new fix here). While we're here, let's also check the error result of safe_create_leading_directories(). We'd presumably notice any failure immediately after when we try to open the file itself, but we can give a more specific error message in this case. Signed-off-by: Jeff King <peff@peff.net>
2019-12-04t9300: create marks files for double-import-marks testLibravatar Jeff King1-0/+2
Our tests confirm that providing two "import-marks" options in a fast-import stream is an error. However, the invoked command would fail even without covering this case, because the marks files themselves do not actually exist. Let's create the files to make sure we fail for the right reason (we actually do, because the option parsing happens before we open anything, but this future-proofs our test). Signed-off-by: Jeff King <peff@peff.net>
2019-12-04t9300: drop some useless uses of catLibravatar Jeff King1-5/+5
These waste a process, and make the line longer than it needs to be. Signed-off-by: Jeff King <peff@peff.net>
2018-12-15Merge branch 'jc/run-command-report-exec-failure-fix' into maintLibravatar Junio C Hamano1-3/+6
A recent update accidentally squelched an error message when the run_command API failed to run a missing command, which has been corrected. * jc/run-command-report-exec-failure-fix: run-command: report exec failure
2018-12-15Merge branch 'js/t9902-send-email-completion-fix' into maintLibravatar Junio C Hamano1-1/+1
* js/t9902-send-email-completion-fix: t9902: 'send-email' test case requires PERL
2018-12-15Merge branch 'js/mailinfo-format-flowed-fix' into maintLibravatar Junio C Hamano1-0/+1
Test portability fix. * js/mailinfo-format-flowed-fix: t4256: mark support files as LF-only
2018-12-14t9902: 'send-email' test case requires PERLLibravatar Johannes Schindelin1-1/+1
The oneline notwithstanding, 13374987dd (completion: use _gitcompbuiltin for format-patch, 2018-11-03) changed also the way send-email options are completed, by asking the git send-email command itself what options it offers. Necessarily, this must fail when built with NO_PERL because send-email itself is a Perl script. Which means that we need the PERL prerequisite for the send-email test case in t9902. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-12-13t4256: mark support files as LF-onlyLibravatar Johannes Schindelin1-0/+1
The test t4256-am-format-flowed.sh requires carefully applying a patch after ignoring padding whitespace. This breaks if the file is munged to include CRLF line endings instead of LF. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-12-12run-command: report exec failureLibravatar Junio C Hamano1-3/+6
In 321fd823 ("run-command: mark path lookup errors with ENOENT", 2018-10-24), we rewrote the logic to execute a command by looking in the directories on $PATH; as a side effect, a request to run a command that is not found on $PATH is noticed even before a child process is forked to execute it. We however stopped to report an exec failure in such a case by mistake. Add a logic to report the error unless silent-exec-failure is requested, to match the original code. Reported-by: John Passaro <john.a.passaro@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-12-04Merge branch 'es/format-patch-range-diff-fix-fix'Libravatar Junio C Hamano1-7/+13
* es/format-patch-range-diff-fix-fix: range-diff: always pass at least minimal diff options
2018-12-04range-diff: always pass at least minimal diff optionsLibravatar Martin Ågren1-7/+13
Commit d8981c3f88 ("format-patch: do not let its diff-options affect --range-diff", 2018-11-30) taught `show_range_diff()` to accept a NULL-pointer as an indication that it should use its own "reasonable default". That fixed a regression from a5170794 ("Merge branch 'ab/range-diff-no-patch'", 2018-11-18), but unfortunately it introduced a regression of its own. In particular, it means we forget the `file` member of the diff options, so rather than placing a range-diff in the cover-letter, we write it to stdout. In order to fix this, rewrite the two callers adjusted by d8981c3f88 to instead create a "dummy" set of diff options where they only fill in the fields we absolutely require, such as output file and color. Modify and extend the existing tests to try and verify that the right contents end up in the right place. Don't revert `show_range_diff()`, i.e., let it keep accepting NULL. Rather than removing what is dead code and figuring out it isn't actually dead and we've broken 2.20, just leave it for now. [es: retain diff coloring when going to stdout] Signed-off-by: Martin Ågren <martin.agren@gmail.com> Signed-off-by: Eric Sunshine <sunshine@sunshineco.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-12-01Merge branch 'sg/test-BUG'Libravatar Junio C Hamano7-23/+26
test framework has been updated to make a bug in the test script (as opposed to bugs in Git that are discovered by running the tests) stand out more prominently. * sg/test-BUG: tests: send "bug in the test script" errors to the script's stderr
2018-12-01Merge branch 'sg/test-cmp-rev'Libravatar Junio C Hamano1-3/+17
Test framework update. * sg/test-cmp-rev: test-lib-functions: make 'test_cmp_rev' more informative on failure
2018-12-01Merge branch 'sg/daemon-test-signal-fix'Libravatar Junio C Hamano1-1/+1
Test fix. * sg/daemon-test-signal-fix: t/lib-git-daemon: fix signal checking
2018-12-01Merge branch 'ab/replace-graft-with-replace-advice'Libravatar Junio C Hamano1-1/+4
The advice message to tell the user to migrate an existing graft file to the replace system when a graft file was read was shown even when "git replace --convert-graft-file" command, which is the way the message suggests to use, was running, which made little sense. * ab/replace-graft-with-replace-advice: advice: don't pointlessly suggest --convert-graft-file
2018-12-01Merge branch 'js/rebase-stat-unrelated-fix'Libravatar Junio C Hamano1-0/+10
"git rebase --stat" to transplant a piece of history onto a totally unrelated history were not working before and silently showed wrong result. With the recent reimplementation in C, it started to instead die with an error message, as the original logic was not prepared to cope with this case. This has now been fixed. * js/rebase-stat-unrelated-fix: rebase --stat: fix when rebasing to an unrelated history
2018-11-30rebase --stat: fix when rebasing to an unrelated historyLibravatar Johannes Schindelin1-0/+10
When rebasing to a commit history that has no common commits with the current branch, there is no merge base. In diffstat mode, this means that we cannot compare to the merge base, but we have to compare to the empty tree instead. Also, if running in verbose diffstat mode, we should not output Changes from <merge-base> to <onto> as that does not make sense without any merge base. Note: neither scripted nor built-in versoin of `git rebase` were prepared for this situation well. We use this opportunity not only to fix the bug(s), but also to make both versions' output consistent in this instance. And add a regression test to keep this working in all eternity. Reported-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-11-30rebase: fix GIT_REFLOG_ACTION regressionLibravatar Johannes Schindelin1-0/+26
The scripted version of "rebase" honored the `GIT_REFLOG_ACTION`, and some automation scripts expected the reflog entries to be prefixed with "rebase -i", not "rebase", after running "rebase -i". This regressed in the reimplementation in C. Fix that, and add a regression test, both with `GIT_REFLOG_ACTION` set and unset. Note: the reflog message for "rebase finished" did *not* honor GIT_REFLOG_ACTION, and as we are very late in the v2.20.0-rcN phase, we leave that bug for later (as it seems that that bug has been with us from the very beginning). Reported by Ian Jackson. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-11-29advice: don't pointlessly suggest --convert-graft-fileLibravatar Ævar Arnfjörð Bjarmason1-1/+4
The advice to run 'git replace --convert-graft-file' added in f9f99b3f7d ("Deprecate support for .git/info/grafts", 2018-04-29) didn't add an exception for the 'git replace --convert-graft-file' codepath itself. As a result we'd suggest running --convert-graft-file while the user was running --convert-graft-file, which makes no sense. Before: $ git replace --convert-graft-file hint: Support for <GIT_DIR>/info/grafts is deprecated hint: and will be removed in a future Git version. hint: hint: Please use "git replace --convert-graft-file" hint: to convert the grafts into replace refs. hint: hint: Turn this message off by running hint: "git config advice.graftFileDeprecated false" Add a check for that case and skip printing the advice while the user is busy following our advice. Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-11-27t/lib-git-daemon: fix signal checkingLibravatar SZEDER Gábor1-1/+1
Test scripts checking 'git daemon' stop the daemon with a TERM signal, and the 'stop_git_daemon' helper checks the daemon's exit status to make sure that it indeed died because of that signal. This check is bogus since 03c39b3458 (t/lib-git-daemon: use test_match_signal, 2016-06-24), for two reasons: - Right after killing 'git daemon', 'stop_git_daemon' saves its exit status in a variable, but since 03c39b3458 the condition checking the exit status looks at '$?', which at this point is not the exit status of 'git daemon', but that of the variable assignment, i.e. it's always 0. - The unexpected exit status should abort the whole test script with 'error', but it doesn't, because 03c39b3458 forgot to negate 'test_match_signal's exit status in the condition. This patch fixes both issues. Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-11-26Merge branch 'tb/clone-case-smashing-warning-test'Libravatar Junio C Hamano1-1/+1
The code recently added to "git clone" to see if the platform's filesystem is adequate to check out and use the project code correctly (e.g. a case smashing filesystem cannot be used for a project with two files whose paths are different only in case) was meant to help Windows users, but the test for it was not enabled for that platform, which has been corrected. * tb/clone-case-smashing-warning-test: t5601-99: Enable colliding file detection for MINGW