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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>
2018-09-27Sync with 2.17.2Libravatar Junio C Hamano2-0/+77
* maint-2.17: Git 2.17.2 fsck: detect submodule paths starting with dash fsck: detect submodule urls starting with dash Git 2.16.5 Git 2.15.3 Git 2.14.5 submodule-config: ban submodule paths that start with a dash submodule-config: ban submodule urls that start with dash submodule--helper: use "--" to signal end of clone options
2018-09-27fsck: detect submodule paths starting with dashLibravatar Jeff King1-0/+8
As with urls, submodule paths with dashes are ignored by git, but may end up confusing older versions. Detecting them via fsck lets us prevent modern versions of git from being a vector to spread broken .gitmodules to older versions. Compared to blocking leading-dash urls, though, this detection may be less of a good idea: 1. While such paths provide confusing and broken results, they don't seem to actually work as option injections against anything except "cd". In particular, the submodule code seems to canonicalize to an absolute path before running "git clone" (so it passes /your/clone/-sub). 2. It's more likely that we may one day make such names actually work correctly. Even after we revert this fsck check, it will continue to be a hassle until hosting servers are all updated. On the other hand, it's not entirely clear that the behavior in older versions is safe. And if we do want to eventually allow this, we may end up doing so with a special syntax anyway (e.g., writing "./-sub" in the .gitmodules file, and teaching the submodule code to canonicalize it when comparing). So on balance, this is probably a good protection. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-09-27fsck: detect submodule urls starting with dashLibravatar Jeff King1-0/+15
Urls with leading dashes can cause mischief on older versions of Git. We should detect them so that they can be rejected by receive.fsckObjects, preventing modern versions of git from being a vector by which attacks can spread. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-09-27Sync with 2.16.5Libravatar Junio C Hamano2-0/+54
* maint-2.16: Git 2.16.5 Git 2.15.3 Git 2.14.5 submodule-config: ban submodule paths that start with a dash submodule-config: ban submodule urls that start with dash submodule--helper: use "--" to signal end of clone options
2018-09-27Sync with 2.15.3Libravatar Junio C Hamano2-0/+54
* maint-2.15: Git 2.15.3 Git 2.14.5 submodule-config: ban submodule paths that start with a dash submodule-config: ban submodule urls that start with dash submodule--helper: use "--" to signal end of clone options
2018-09-27Sync with Git 2.14.4Libravatar Junio C Hamano2-0/+54
* maint-2.14: Git 2.14.5 submodule-config: ban submodule paths that start with a dash submodule-config: ban submodule urls that start with dash submodule--helper: use "--" to signal end of clone options
2018-09-27submodule-config: ban submodule paths that start with a dashLibravatar Jeff King1-0/+20
We recently banned submodule urls that look like command-line options. This is the matching change to ban leading-dash paths. As with the urls, this should not break any use cases that currently work. Even with our "--" separator passed to git-clone, git-submodule.sh gets confused. Without the code portion of this patch, the clone of "-sub" added in t7417 would yield results like: /path/to/git-submodule: 410: cd: Illegal option -s /path/to/git-submodule: 417: cd: Illegal option -s /path/to/git-submodule: 410: cd: Illegal option -s /path/to/git-submodule: 417: cd: Illegal option -s Fetched in submodule path '-sub', but it did not contain b56243f8f4eb91b2f1f8109452e659f14dd3fbe4. Direct fetching of that commit failed. Moreover, naively adding such a submodule doesn't work: $ git submodule add $url -sub The following path is ignored by one of your .gitignore files: -sub even though there is no such ignore pattern (the test script hacks around this with a well-placed "git mv"). Unlike leading-dash urls, though, it's possible that such a path _could_ be useful if we eventually made it work. So this commit should be seen not as recommending a particular policy, but rather temporarily closing off a broken and possibly dangerous code-path. We may revisit this decision later. There are two minor differences to the tests in t7416 (that covered urls): 1. We don't have a "./-sub" escape hatch to make this work, since the submodule code expects to be able to match canonical index names to the path field (so you are free to add submodule config with that path, but we would never actually use it, since an index entry would never start with "./"). 2. After this patch, cloning actually succeeds. Since we ignore the submodule.*.path value, we fail to find a config stanza for our submodule at all, and simply treat it as inactive. We still check for the "ignoring" message. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-09-27submodule-config: ban submodule urls that start with dashLibravatar Jeff King1-0/+34
The previous commit taught the submodule code to invoke our "git clone $url $path" with a "--" separator so that we aren't confused by urls or paths that start with dashes. However, that's just one code path. It's not clear if there are others, and it would be an easy mistake to add one in the future. Moreover, even with the fix in the previous commit, it's quite hard to actually do anything useful with such an entry. Any url starting with a dash must fall into one of three categories: - it's meant as a file url, like "-path". But then any clone is not going to have the matching path, since it's by definition relative inside the newly created clone. If you spell it as "./-path", the submodule code sees the "/" and translates this to an absolute path, so it at least works (assuming the receiver has the same filesystem layout as you). But that trick does not apply for a bare "-path". - it's meant as an ssh url, like "-host:path". But this already doesn't work, as we explicitly disallow ssh hostnames that begin with a dash (to avoid option injection against ssh). - it's a remote-helper scheme, like "-scheme::data". This _could_ work if the receiver bends over backwards and creates a funny-named helper like "git-remote--scheme". But normally there would not be any helper that matches. Since such a url does not work today and is not likely to do anything useful in the future, let's simply disallow them entirely. That protects the existing "git clone" path (in a belt-and-suspenders way), along with any others that might exist. Our tests cover two cases: 1. A file url with "./" continues to work, showing that there's an escape hatch for people with truly silly repo names. 2. A url starting with "-" is rejected. Note that we expect case (2) to fail, but it would have done so even without this commit, for the reasons given above. So instead of just expecting failure, let's also check for the magic word "ignoring" on stderr. That lets us know that we failed for the right reason. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-06-19Merge branch 'cf/submodule-progress-dissociate'Libravatar Junio C Hamano1-2/+4
* cf/submodule-progress-dissociate: t7400: encapsulate setup code in test_expect_success
2018-06-19Merge branch 'js/rebase-i-root-fix'Libravatar Junio C Hamano1-1/+2
* js/rebase-i-root-fix: t3404: check root commit in 'rebase -i --root reword root commit'
2018-06-19t7400: encapsulate setup code in test_expect_successLibravatar Stefan Beller1-2/+4
When running t7400 in a shell you observe more output than expected: ... ok 8 - setup - hide init subdirectory ok 9 - setup - repository to add submodules to ok 10 - submodule add [master (root-commit) d79ce16] one Author: A U Thor <author@example.com> 1 file changed, 1 insertion(+) create mode 100644 one.t ok 11 - redirected submodule add does not show progress ok 12 - redirected submodule add --progress does show progress ok 13 - submodule add to .gitignored path fails ... Fix the output by encapsulating the setup code in test_expect_success Signed-off-by: Stefan Beller <sbeller@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-06-19t3404: check root commit in 'rebase -i --root reword root commit'Libravatar Todd Zullinger1-1/+2
When testing a reworded root commit, ensure that the squash-onto commit which is created and amended is still the root commit. Suggested-by: Phillip Wood <phillip.wood@talktalk.net> Helped-by: Johannes Schindelin <Johannes.Schindelin@gmx.de> Signed-off-by: Todd Zullinger <tmz@pobox.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-06-18Merge branch 'sg/t7406-chain-fix'Libravatar Junio C Hamano1-6/+6
Test fix. * sg/t7406-chain-fix: t7406-submodule-update: fix broken &&-chains
2018-06-18Merge branch 'ks/branch-set-upstream'Libravatar Junio C Hamano1-1/+1
A test title has been reworded to clarify it. * ks/branch-set-upstream: t3200: clarify description of --set-upstream test
2018-06-18Merge branch 'js/rebase-i-root-fix'Libravatar Junio C Hamano1-0/+9
A regression to "rebase -i --root" introduced during this cycle has been fixed. * js/rebase-i-root-fix: rebase --root: fix amending root commit messages rebase --root: demonstrate a bug while amending root commit messages
2018-06-18Merge branch 'jk/ewah-bounds-check'Libravatar Junio C Hamano1-0/+13
The code to read compressed bitmap was not careful to avoid reading past the end of the file, which has been corrected. * jk/ewah-bounds-check: ewah: adjust callers of ewah_read_mmap() ewah_read_mmap: bounds-check mmap reads
2018-06-18Merge branch 'ld/git-p4-updates'Libravatar Junio C Hamano3-0/+126
"git p4" updates. * ld/git-p4-updates: git-p4: auto-size the block git-p4: narrow the scope of exceptions caught when parsing an int git-p4: raise exceptions from p4CmdList based on error from p4 server git-p4: better error reporting when p4 fails git-p4: add option to disable syncing of p4/master with p4 git-p4: disable-rebase: allow setting this via configuration git-p4: add options --commit and --disable-rebase
2018-06-18t7406-submodule-update: fix broken &&-chainsLibravatar SZEDER Gábor1-6/+6
Three tests in 't7406-submodule-update' contain broken &&-chains, but since they are all in subshells, chain-lint couldn't notice them. Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-06-18rebase --root: fix amending root commit messagesLibravatar Johannes Schindelin1-1/+1
The code path that triggered that "BUG" really does not want to run without an explicit commit message. In the case where we want to amend a commit message, we have an *implicit* commit message, though: the one of the commit to amend. Therefore, this code path should not even be entered. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-06-18rebase --root: demonstrate a bug while amending root commit messagesLibravatar Todd Zullinger1-0/+9
When splitting a repository, running `git rebase -i --root` to reword the initial commit, Git dies with BUG: sequencer.c:795: root commit without message. Signed-off-by: Todd Zullinger <tmz@pobox.com> Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-06-18ewah_read_mmap: bounds-check mmap readsLibravatar Jeff King1-0/+13
The on-disk ewah format tells us how big the ewah data is, and we blindly read that much from the buffer without considering whether the mmap'd data is long enough, which can lead to out-of-bound reads. Let's make sure we have data available before reading it, both for the ewah header/footer as well as for the bit data itself. In particular: - keep our ptr/len pair in sync as we move through the buffer, and check it before each read - check the size for integer overflow (this should be impossible on 64-bit, as the size is given as a 32-bit count of 8-byte words, but is possible on a 32-bit system) - return the number of bytes read as an ssize_t instead of an int, again to prevent integer overflow - compute the return value using a pointer difference; this should yield the same result as the existing code, but makes it more obvious that we got our computations right The included test is far from comprehensive, as it just picks a static point at which to truncate the generated bitmap. But in practice this will hit in the middle of an ewah and make sure we're at least exercising this code. Reported-by: Luat Nguyen <root@l4w.io> Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>