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2020-05-04ref-filter: apply fallback refname sort only after all user sortsLibravatar Jeff King2-8/+53
Commit 9e468334b4 (ref-filter: fallback on alphabetical comparison, 2015-10-30) taught ref-filter's sort to fallback to comparing refnames. But it did it at the wrong level, overriding the comparison result for a single "--sort" key from the user, rather than after all sort keys have been exhausted. This worked correctly for a single "--sort" option, but not for multiple ones. We'd break any ties in the first key with the refname and never evaluate the second key at all. To make matters even more interesting, we only applied this fallback sometimes! For a field like "taggeremail" which requires a string comparison, we'd truly return the result of strcmp(), even if it was 0. But for numerical "value" fields like "taggerdate", we did apply the fallback. And that's why our multiple-sort test missed this: it uses taggeremail as the main comparison. So let's start by adding a much more rigorous test. We'll have a set of commits expressing every combination of two tagger emails, dates, and refnames. Then we can confirm that our sort is applied with the correct precedence, and we'll be hitting both the string and value comparators. That does show the bug, and the fix is simple: moving the fallback to the outer compare_refs() function, after all ref_sorting keys have been exhausted. Note that in the outer function we don't have an "ignore_case" flag, as it's part of each individual ref_sorting element. It's debatable what such a fallback should do, since we didn't use the user's keys to match. But until now we have been trying to respect that flag, so the least-invasive thing is to try to continue to do so. Since all callers in the current code either set the flag for all keys or for none, we can just pull the flag from the first key. In a hypothetical world where the user really can flip the case-insensitivity of keys separately, we may want to extend the code to distinguish that case from a blanket "--ignore-case". Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-05-04ref-filter: apply --ignore-case to all sorting keysLibravatar Jeff King6-3/+51
All of the ref-filter users (for-each-ref, branch, and tag) take an --ignore-case option which makes filtering and sorting case-insensitive. However, this option was applied only to the first element of the ref_sorting list. So: git for-each-ref --ignore-case --sort=refname would do what you expect, but: git for-each-ref --ignore-case --sort=refname --sort=taggername would sort the primary key (taggername) case-insensitively, but sort the refname case-sensitively. We have two options here: - teach callers to set ignore_case on the whole list - replace the ref_sorting list with a struct that contains both the list of sorting keys, as well as options that apply to _all_ keys I went with the first one here, as it gives more flexibility if we later want to let the users set the flag per-key (presumably through some special syntax when defining the key; for now it's all or nothing through --ignore-case). The new test covers this by sorting on both tagger and subject case-insensitively, which should compare "a" and "A" identically, but still sort them before "b" and "B". We'll break ties by sorting on the refname to give ourselves a stable output (this is actually supposed to be done automatically, but there's another bug which will be fixed in the next commit). Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-19Git 2.20.4Libravatar Jonathan Nieder12-42/+474
This merges up the security fix from v2.17.5. Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
2020-04-19Git 2.19.5Libravatar Jonathan Nieder11-42/+469
This merges up the security fix from v2.17.5. Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
2020-04-19Git 2.18.4Libravatar Jonathan Nieder10-42/+464
This merges up the security fix from v2.17.5. Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
2020-04-19Git 2.17.5Libravatar Jeff King3-2/+24
Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
2020-04-19fsck: reject URL with empty host in .gitmodulesLibravatar Jonathan Nieder2-3/+39
Git's URL parser interprets https:///example.com/repo.git to have no host and a path of "example.com/repo.git". Curl, on the other hand, internally redirects it to https://example.com/repo.git. As a result, until "credential: parse URL without host as empty host, not unset", tricking a user into fetching from such a URL would cause Git to send credentials for another host to example.com. Teach fsck to block and detect .gitmodules files using such a URL to prevent sharing them with Git versions that are not yet protected. A relative URL in a .gitmodules file could also be used to trigger this. The relative URL resolver used for .gitmodules does not normalize sequences of slashes and can follow ".." components out of the path part and to the host part of a URL, meaning that such a relative URL can be used to traverse from a https://foo.example.com/innocent superproject to a https:///attacker.example.com/exploit submodule. Fortunately, redundant extra slashes in .gitmodules are rare, so we can catch this by detecting one after a leading sequence of "./" and "../" components. Helped-by: Jeff King <peff@peff.net> Signed-off-by: Jonathan Nieder <jrnieder@gmail.com> Reviewed-by: Jeff King <peff@peff.net>
2020-04-19credential: treat URL with empty scheme as invalidLibravatar Jonathan Nieder3-3/+43
Until "credential: refuse to operate when missing host or protocol", Git's credential handling code interpreted URLs with empty scheme to mean "give me credentials matching this host for any protocol". Luckily libcurl does not recognize such URLs (it tries to look for a protocol named "" and fails). Just in case that changes, let's reject them within Git as well. This way, credential_from_url is guaranteed to always produce a "struct credential" with protocol and host set. Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
2020-04-19credential: treat URL without scheme as invalidLibravatar Jonathan Nieder4-9/+84
libcurl permits making requests without a URL scheme specified. In this case, it guesses the URL from the hostname, so I can run git ls-remote http::ftp.example.com/path/to/repo and it would make an FTP request. Any user intentionally using such a URL is likely to have made a typo. Unfortunately, credential_from_url is not able to determine the host and protocol in order to determine appropriate credentials to send, and until "credential: refuse to operate when missing host or protocol", this resulted in another host's credentials being leaked to the named host. Teach credential_from_url_gently to consider such a URL to be invalid so that fsck can detect and block gitmodules files with such URLs, allowing server operators to avoid serving them to downstream users running older versions of Git. This also means that when such URLs are passed on the command line, Git will print a clearer error so affected users can switch to the simpler URL that explicitly specifies the host and protocol they intend. One subtlety: .gitmodules files can contain relative URLs, representing a URL relative to the URL they were cloned from. The relative URL resolver used for .gitmodules can follow ".." components out of the path part and past the host part of a URL, meaning that such a relative URL can be used to traverse from a https://foo.example.com/innocent superproject to a https::attacker.example.com/exploit submodule. Fortunately a leading ':' in the first path component after a series of leading './' and '../' components is unlikely to show up in other contexts, so we can catch this by detecting that pattern. Reported-by: Jeff King <peff@peff.net> Signed-off-by: Jonathan Nieder <jrnieder@gmail.com> Reviewed-by: Jeff King <peff@peff.net>
2020-04-19credential: die() when parsing invalid urlsLibravatar Jeff King2-6/+3
When we try to initialize credential loading by URL and find that the URL is invalid, we set all fields to NULL in order to avoid acting on malicious input. Later when we request credentials, we diagonse the erroneous input: fatal: refusing to work with credential missing host field This is problematic in two ways: - The message doesn't tell the user *why* we are missing the host field, so they can't tell from this message alone how to recover. There can be intervening messages after the original warning of bad input, so the user may not have the context to put two and two together. - The error only occurs when we actually need to get a credential. If the URL permits anonymous access, the only encouragement the user gets to correct their bogus URL is a quiet warning. This is inconsistent with the check we perform in fsck, where any use of such a URL as a submodule is an error. When we see such a bogus URL, let's not try to be nice and continue without helpers. Instead, die() immediately. This is simpler and obviously safe. And there's very little chance of disrupting a normal workflow. It's _possible_ that somebody has a legitimate URL with a raw newline in it. It already wouldn't work with credential helpers, so this patch steps that up from an inconvenience to "we will refuse to work with it at all". If such a case does exist, we should figure out a way to work with it (especially if the newline is only in the path component, which we normally don't even pass to helpers). But until we see a real report, we're better off being defensive. Reported-by: Carlo Arenas <carenas@gmail.com> Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
2020-04-19fsck: convert gitmodules url to URL passed to curlLibravatar Jonathan Nieder2-5/+118
In 07259e74ec1 (fsck: detect gitmodules URLs with embedded newlines, 2020-03-11), git fsck learned to check whether URLs in .gitmodules could be understood by the credential machinery when they are handled by git-remote-curl. However, the check is overbroad: it checks all URLs instead of only URLs that would be passed to git-remote-curl. In principle a git:// or file:/// URL does not need to follow the same conventions as an http:// URL; in particular, git:// and file:// protocols are not succeptible to issues in the credential API because they do not support attaching credentials. In the HTTP case, the URL in .gitmodules does not always match the URL that would be passed to git-remote-curl and the credential machinery: Git's URL syntax allows specifying a remote helper followed by a "::" delimiter and a URL to be passed to it, so that git ls-remote http::https://example.com/repo.git invokes git-remote-http with https://example.com/repo.git as its URL argument. With today's checks, that distinction does not make a difference, but for a check we are about to introduce (for empty URL schemes) it will matter. .gitmodules files also support relative URLs. To ensure coverage for the https based embedded-newline attack, urldecode and check them directly for embedded newlines. Helped-by: Jeff King <peff@peff.net> Signed-off-by: Jonathan Nieder <jrnieder@gmail.com> Reviewed-by: Jeff King <peff@peff.net>
2020-04-19credential: refuse to operate when missing host or protocolLibravatar Jeff King2-14/+40
The credential helper protocol was designed to be very flexible: the fields it takes as input are treated as a pattern, and any missing fields are taken as wildcards. This allows unusual things like: echo protocol=https | git credential reject to delete all stored https credentials (assuming the helpers themselves treat the input that way). But when helpers are invoked automatically by Git, this flexibility works against us. If for whatever reason we don't have a "host" field, then we'd match _any_ host. When you're filling a credential to send to a remote server, this is almost certainly not what you want. Prevent this at the layer that writes to the credential helper. Add a check to the credential API that the host and protocol are always passed in, and add an assertion to the credential_write function that speaks credential helper protocol to be doubly sure. There are a few ways this can be triggered in practice: - the "git credential" command passes along arbitrary credential parameters it reads from stdin. - until the previous patch, when the host field of a URL is empty, we would leave it unset (rather than setting it to the empty string) - a URL like "example.com/foo.git" is treated by curl as if "http://" was present, but our parser sees it as a non-URL and leaves all fields unset - the recent fix for URLs with embedded newlines blanks the URL but otherwise continues. Rather than having the desired effect of looking up no credential at all, many helpers will return _any_ credential Our earlier test for an embedded newline didn't catch this because it only checked that the credential was cleared, but didn't configure an actual helper. Configuring the "verbatim" helper in the test would show that it is invoked (it's obviously a silly helper which doesn't look at its input, but the point is that it shouldn't be run at all). Since we're switching this case to die(), we don't need to bother with a helper. We can see the new behavior just by checking that the operation fails. We'll add new tests covering partial input as well (these can be triggered through various means with url-parsing, but it's simpler to just check them directly, as we know we are covered even if the url parser changes behavior in the future). [jn: changed to die() instead of logging and showing a manual username/password prompt] Reported-by: Carlo Arenas <carenas@gmail.com> Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
2020-04-19credential: parse URL without host as empty host, not unsetLibravatar Jeff King3-2/+19
We may feed a URL like "cert:///path/to/cert.pem" into the credential machinery to get the key for a client-side certificate. That credential has no hostname field, which is about to be disallowed (to avoid confusion with protocols where a helper _would_ expect a hostname). This means as of the next patch, credential helpers won't work for unlocking certs. Let's fix that by doing two things: - when we parse a url with an empty host, set the host field to the empty string (asking only to match stored entries with an empty host) rather than NULL (asking to match _any_ host). - when we build a cert:// credential by hand, similarly assign an empty string It's the latter that is more likely to impact real users in practice, since it's what's used for http connections. But we don't have good infrastructure to test it. The url-parsing version will help anybody using git-credential in a script, and is easy to test. Signed-off-by: Jeff King <peff@peff.net> Reviewed-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
2020-04-19t0300: use more realistic inputsLibravatar Jeff King1-4/+85
Many of the tests in t0300 give partial inputs to git-credential, omitting a protocol or hostname. We're checking only high-level things like whether and how helpers are invoked at all, and we don't care about specific hosts. However, in preparation for tightening up the rules about when we're willing to run a helper, let's start using input that's a bit more realistic: pretend as if http://example.com is being examined. This shouldn't change the point of any of the tests, but do note we have to adjust the expected output to accommodate this (filling a credential will repeat back the protocol/host fields to stdout, and the helper debug messages and askpass prompt will change on stderr). Signed-off-by: Jeff King <peff@peff.net> Reviewed-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
2020-04-19t0300: make "quit" helper more realisticLibravatar Jeff King1-3/+13
We test a toy credential helper that writes "quit=1" and confirms that we stop running other helpers. However, that helper is unrealistic in that it does not bother to read its stdin at all. For now we don't send any input to it, because we feed git-credential a blank credential. But that will change in the next patch, which will cause this test to racily fail, as git-credential will get SIGPIPE writing to the helper rather than exiting because it was asked to. Let's make this one-off helper more like our other sample helpers, and have it source the "dump" script. That will read stdin, fixing the SIGPIPE problem. But it will also write what it sees to stderr. We can make the test more robust by checking that output, which confirms that we do run the quit helper, don't run any other helpers, and exit for the reason we expected. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
2020-03-17Git 2.20.3Libravatar Junio C Hamano12-7/+132
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-03-17Git 2.19.4Libravatar Junio C Hamano11-7/+127
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-03-17Git 2.18.3Libravatar Junio C Hamano10-7/+122
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-03-17Git 2.17.4Libravatar Junio C Hamano3-2/+18
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-03-12fsck: detect gitmodules URLs with embedded newlinesLibravatar Jeff King2-2/+32
The credential protocol can't handle values with newlines. We already detect and block any such URLs from being used with credential helpers, but let's also add an fsck check to detect and block gitmodules files with such URLs. That will let us notice the problem earlier when transfer.fsckObjects is turned on. And in particular it will prevent bad objects from spreading, which may protect downstream users running older versions of Git. We'll file this under the existing gitmodulesUrl flag, which covers URLs with option injection. There's really no need to distinguish the exact flaw in the URL in this context. Likewise, I've expanded the description of t7416 to cover all types of bogus URLs.
2020-03-12credential: detect unrepresentable values when parsing urlsLibravatar Jeff King3-4/+60
The credential protocol can't represent newlines in values, but URLs can embed percent-encoded newlines in various components. A previous commit taught the low-level writing routines to die() when encountering this, but we can be a little friendlier to the user by detecting them earlier and handling them gracefully. This patch teaches credential_from_url() to notice such components, issue a warning, and blank the credential (which will generally result in prompting the user for a username and password). We blank the whole credential in this case. Another option would be to blank only the invalid component. However, we're probably better off not feeding a partially-parsed URL result to a credential helper. We don't know how a given helper would handle it, so we're better off to err on the side of matching nothing rather than something unexpected. The die() call in credential_write() is _probably_ impossible to reach after this patch. Values should end up in credential structs only by URL parsing (which is covered here), or by reading credential protocol input (which by definition cannot read a newline into a value). But we should definitely keep the low-level check, as it's our final and most accurate line of defense against protocol injection attacks. Arguably it could become a BUG(), but it probably doesn't matter much either way. Note that the public interface of credential_from_url() grows a little more than we need here. We'll use the extra flexibility in a future patch to help fsck catch these cases.
2020-03-12t/lib-credential: use test_i18ncmp to check stderrLibravatar Jeff King1-1/+1
The credential tests have a "check" function which feeds some input to git-credential and checks the stdout and stderr. We look for exact matches in the output. For stdout, this makes sense; the output is the credential protocol. But for stderr, we may be showing various diagnostic messages, or the prompts fed to the askpass program, which could be translated. Let's mark them as such.
2020-03-12credential: avoid writing values with newlinesLibravatar Jeff King2-0/+8
The credential protocol that we use to speak to helpers can't represent values with newlines in them. This was an intentional design choice to keep the protocol simple, since none of the values we pass should generally have newlines. However, if we _do_ encounter a newline in a value, we blindly transmit it in credential_write(). Such values may break the protocol syntax, or worse, inject new valid lines into the protocol stream. The most likely way for a newline to end up in a credential struct is by decoding a URL with a percent-encoded newline. However, since the bug occurs at the moment we write the value to the protocol, we'll catch it there. That should leave no possibility of accidentally missing a code path that can trigger the problem. At this level of the code we have little choice but to die(). However, since we'd not ever expect to see this case outside of a malicious URL, that's an acceptable outcome. Reported-by: Felix Wilhelm <fwilhelm@google.com>
2019-12-06Git 2.20.2Libravatar Johannes Schindelin3-2/+20
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2019-12-06submodule: defend against submodule.update = !command in .gitmodulesLibravatar Jonathan Nieder1-0/+2
In v2.15.4, we started to reject `submodule.update` settings in `.gitmodules`. Let's raise a BUG if it somehow still made it through from anywhere but the Git config. Signed-off-by: Jonathan Nieder <jrnieder@gmail.com> Signed-off-by: Johannes Schindelin <Johannes.Schindelin@gmx.de>
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 Schindelin40-82/+914
* 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 ...
2019-12-06Git 2.19.3Libravatar Johannes Schindelin3-2/+10
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2019-12-06Sync with 2.18.2Libravatar Johannes Schindelin39-82/+906
* 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 ...
2019-12-06Git 2.18.2Libravatar Johannes Schindelin3-2/+10
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2019-12-06Sync with 2.17.3Libravatar Johannes Schindelin38-83/+898
* 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 ...
2019-12-06Git 2.17.3Libravatar Johannes Schindelin3-2/+14
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2019-12-06fsck: reject submodule.update = !command in .gitmodulesLibravatar Jonathan Nieder2-0/+21
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 Schindelin37-82/+865
* 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 ...
2019-12-06Git 2.16.6Libravatar Johannes Schindelin3-2/+10
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
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 Schindelin35-77/+842
* 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 ...
2019-12-06Git 2.15.4Libravatar Johannes Schindelin3-2/+13
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2019-12-06submodule: reject submodule.update = !command in .gitmodulesLibravatar Jonathan Nieder3-11/+20
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 Schindelin31-66/+811
* 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 ...
2019-12-06Git 2.14.6Libravatar Johannes Schindelin3-2/+56
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2019-12-05Merge branch 'win32-accommodate-funny-drive-names'Libravatar Johannes Schindelin4-6/+54
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 Schindelin11-4/+127
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>
2019-12-05Merge branch 'fix-mingw-quoting-bug'Libravatar Johannes Schindelin3-5/+156
This patch fixes a vulnerability in the Windows-specific code where a submodule names ending in a backslash were quoted incorrectly, and that bug could be abused to insert command-line parameters e.g. to `ssh` in a recursive clone. Note: this bug is Windows-only, as we have to construct a command line for the process-to-spawn, unlike Linux/macOS, where `execv()` accepts an already-split command line. While at it, other quoting issues are fixed as well. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2019-12-05Merge branch 'dubiously-nested-submodules'Libravatar Johannes Schindelin4-2/+79
Recursive clones are currently affected by a vulnerability that is caused by too-lax validation of submodule names. This topic branch fixes that. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2019-12-05Merge branch 'turn-on-protectntfs-by-default'Libravatar Johannes Schindelin3-28/+31
This patch series makes it safe to use Git on Windows drives, even if running on a mounted network share or within the Windows Subsystem for Linux (WSL). This topic branch addresses CVE-2019-1353. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2019-12-05mingw: handle `subst`-ed "DOS drives"Libravatar Johannes Schindelin4-3/+36
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>
2019-12-05Merge branch 'disallow-dotgit-via-ntfs-alternate-data-streams'Libravatar Johannes Schindelin6-8/+162
This patch series plugs an attack vector we had overlooked in our December 2014 work on `core.protectNTFS`. Essentially, the path `.git::$INDEX_ALLOCATION/config` is interpreted as `.git/config` when NTFS Alternate Data Streams are available (which they are on Windows, and at least on network shares that are SMB-mounted on macOS). Needless to say: we don't want that. In fact, we want to stay on the very safe side and not even special-case the `$INDEX_ALLOCATION` stream type: let's just prevent Git from touching _any_ explicitly specified Alternate Data Stream of `.git`. In essence, we'll prevent Git from tracking, or writing to, any path with a segment of the form `.git:<anything>`. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2019-12-05mingw: refuse to access paths with trailing spaces or periodsLibravatar Johannes Schindelin8-2/+123
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>