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2021-10-13Merge branch 'jh/builtin-fsmonitor-part1'Libravatar Junio C Hamano2-22/+171
Built-in fsmonitor (part 1). * jh/builtin-fsmonitor-part1: t/helper/simple-ipc: convert test-simple-ipc to use start_bg_command run-command: create start_bg_command simple-ipc/ipc-win32: add Windows ACL to named pipe simple-ipc/ipc-win32: add trace2 debugging simple-ipc: move definition of ipc_active_state outside of ifdef simple-ipc: preparations for supporting binary messages. trace2: add trace2_child_ready() to report on background children
2021-10-13Merge branch 'ab/config-based-hooks-1'Libravatar Junio C Hamano1-1/+1
Mostly preliminary clean-up in the hook API. * ab/config-based-hooks-1: hook-list.h: add a generated list of hooks, like config-list.h hook.c users: use "hook_exists()" instead of "find_hook()" hook.c: add a hook_exists() wrapper and use it in bugreport.c hook.[ch]: move find_hook() from run-command.c to hook.c Makefile: remove an out-of-date comment Makefile: don't perform "mv $@+ $@" dance for $(GENERATED_H) Makefile: stop hardcoding {command,config}-list.h Makefile: mark "check" target as .PHONY
2021-09-27lazyload.h: use an even more generic function pointer than FARPROCLibravatar Carlo Marcelo Arenas Belón1-3/+6
gcc will helpfully raise a -Wcast-function-type warning when casting between functions that might have incompatible return types (ex: GetUserNameExW returns bool which is only half the size of the return type from FARPROC which is long long), so create a new type that could be used as a completely generic function pointer and cast through it instead. Additionaly remove the -Wno-incompatible-pointer-types temporary flag added in 27e0c3c (win32: allow building with pedantic mode enabled, 2021-09-03), as it will be no longer needed. Signed-off-by: Carlo Marcelo Arenas Belón <carenas@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-09-27lazyload.h: fix warnings about mismatching function pointer typesLibravatar Johannes Sixt1-2/+3
Here, GCC warns about every use of the INIT_PROC_ADDR macro, for example: In file included from compat/mingw.c:8: compat/mingw.c: In function 'mingw_strftime': compat/win32/lazyload.h:38:12: warning: assignment to 'size_t (*)(char *, size_t, const char *, const struct tm *)' {aka 'long long unsigned int (*)(char *, long long unsigned int, const char *, const struct tm *)'} from incompatible pointer type 'FARPROC' {aka 'long long int (*)()'} [-Wincompatible-pointer-types] 38 | (function = get_proc_addr(&proc_addr_##function)) | ^ compat/mingw.c:1014:6: note: in expansion of macro 'INIT_PROC_ADDR' 1014 | if (INIT_PROC_ADDR(strftime)) | ^~~~~~~~~~~~~~ (message wrapped for convenience). Insert a cast to keep the compiler happy. A cast is fine in these cases because they are generic function pointer values that have been looked up in a DLL. Helped-by: Carlo Marcelo Arenas Belón <carenas@gmail.com> Signed-off-by: Johannes Sixt <j6t@kdbg.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-09-23Makefile: stop hardcoding {command,config}-list.hLibravatar Ævar Arnfjörð Bjarmason1-1/+1
Change various places that hardcode the names of these two files to refer to either $(GENERATED_H), or to a new generated-hdrs target. That target is consistent with the *-objs targets I recently added in 029bac01a8 (Makefile: add {program,xdiff,test,git,fuzz}-objs & objects targets, 2021-02-23). A subsequent commit will add a new generated hook-list.h. By doing this refactoring we'll only need to add the new file to the GENERATED_H variable, not EXCEPT_HDRS, the vcbuild/README etc. Hardcoding command-list.h there seems to have been a case of copy/paste programming in 976aaedca0 (msvc: add a Makefile target to pre-generate the Visual Studio solution, 2019-07-29). The config-list.h was added later in 709df95b78 (help: move list_config_help to builtin/help, 2020-04-16). Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-09-20Merge branch 'cb/pedantic-build-for-developers'Libravatar Junio C Hamano2-2/+2
Update the build procedure to use the "-pedantic" build when DEVELOPER makefile macro is in effect. * cb/pedantic-build-for-developers: developer: enable pedantic by default win32: allow building with pedantic mode enabled gettext: remove optional non-standard parens in N_() definition
2021-09-20Merge branch 'ab/tr2-leaks-and-fixes'Libravatar Junio C Hamano1-24/+145
The tracing of process ancestry information has been enhanced. * ab/tr2-leaks-and-fixes: tr2: log N parent process names on Linux tr2: do compiler enum check in trace2_collect_process_info() tr2: leave the parent list empty upon failure & don't leak memory tr2: stop leaking "thread_name" memory tr2: clarify TRACE2_PROCESS_INFO_EXIT comment under Linux tr2: remove NEEDSWORK comment for "non-procfs" implementations
2021-09-20simple-ipc/ipc-win32: add Windows ACL to named pipeLibravatar Jeff Hostetler1-11/+129
Set an ACL on the named pipe to allow the well-known group EVERYONE to read and write to the IPC server's named pipe. In the event that the daemon was started with elevation, allow non-elevated clients to communicate with the daemon. Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-09-20simple-ipc/ipc-win32: add trace2 debuggingLibravatar Jeff Hostetler1-1/+24
Create "ipc-debug" category events to log unexpected errors when creating Simple-IPC connections. Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-09-20simple-ipc: preparations for supporting binary messages.Libravatar Jeff Hostetler2-10/+18
Add `command_len` argument to the Simple IPC API. In my original Simple IPC API, I assumed that the request would always be a null-terminated string of text characters. The `command` argument was just a `const char *`. I found a caller that would like to pass a binary command to the daemon, so I am amending the Simple IPC API to receive `const char *command, size_t command_len` arguments. I considered changing the `command` argument to be a `void *`, but the IPC layer simply passes it to the pkt-line layer which takes a `const char *`, so to avoid confusion I left it as is. Note, the response side has always been a `struct strbuf` which includes the buffer and length, so we already support returning a binary answer. (Yes, it feels a little weird returning a binary buffer in a `strbuf`, but it works.) Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-09-08Merge branch 'rs/git-mmap-uses-malloc'Libravatar Junio C Hamano1-1/+6
mmap() imitation used to call xmalloc() that dies upon malloc() failure, which has been corrected to just return an error to the caller to be handled. * rs/git-mmap-uses-malloc: compat: let git_mmap use malloc(3) directly
2021-09-07tr2: log N parent process names on LinuxLibravatar Ævar Arnfjörð Bjarmason1-17/+132
In 2f732bf15e6 (tr2: log parent process name, 2021-07-21) we started logging parent process names, but only logged all parents on Windows. on Linux only the name of the immediate parent process was logged. Extend the functionality added there to also log full parent chain on Linux. This requires us to lookup "/proc/<getppid()>/stat" instead of "/proc/<getppid()>/comm". The "comm" file just contains the name of the process, but the "stat" file has both that information, and the parent PID of that process, see procfs(5). We parse out the parent PID of our own parent, and recursively walk the chain of "/proc/*/stat" files all the way up the chain. A parent PID of 0 indicates the end of the chain. It's possible given the semantics of Linux's PID files that we end up getting an entirely nonsensical chain of processes. It could happen if e.g. we have a chain of processes like: 1 (init) => 321 (bash) => 123 (git) Let's assume that "bash" was started a while ago, and that as shown the OS has already cycled back to using a lower PID for us than our parent process. In the time it takes us to start up and get to trace2_collect_process_info(TRACE2_PROCESS_INFO_STARTUP) our parent process might exit, and be replaced by an entirely different process! We'd racily look up our own getppid(), but in the meantime our parent would exit, and Linux would have cycled all the way back to starting an entirely unrelated process as PID 321. If that happens we'll just silently log incorrect data in our ancestry chain. Luckily we don't need to worry about this except in this specific cycling scenario, as Linux does not have PID randomization. It appears it once did through a third-party feature, but that it was removed around 2006[1]. For anyone worried about this edge case raising PID_MAX via "/proc/sys/kernel/pid_max" will mitigate it, but not eliminate it. One thing we don't need to worry about is getting into an infinite loop when walking "/proc/*/stat". See 353d3d77f4f (trace2: collect Windows-specific process information, 2019-02-22) for the related Windows code that needs to deal with that, and [2] for an explanation of that edge case. Aside from potential race conditions it's also a bit painful to correctly parse the process name out of "/proc/*/stat". A simpler approach is to use fscanf(), see [3] for an implementation of that, but as noted in the comment being added here it would fail in the face of some weird process names, so we need our own parse_proc_stat() to parse it out. With this patch the "ancestry" chain for a trace2 event might look like this: $ GIT_TRACE2_EVENT=/dev/stdout ~/g/git/git version | grep ancestry | jq -r .ancestry [ "bash", "screen", "systemd" ] And in the case of naughty process names like the following. This uses perl's ability to use prctl(PR_SET_NAME, ...). See Perl/perl5@7636ea95c5 (Set the legacy process name with prctl() on assignment to $0 on Linux, 2010-04-15)[4]: $ perl -e '$0 = "(naughty\nname)"; system "GIT_TRACE2_EVENT=/dev/stdout ~/g/git/git version"' | grep ancestry | jq -r .ancestry [ "sh", "(naughty\nname)", "bash", "screen", "systemd" ] 1. https://grsecurity.net/news#grsec2110 2. https://lore.kernel.org/git/48a62d5e-28e2-7103-a5bb-5db7e197a4b9@jeffhostetler.com/ 3. https://lore.kernel.org/git/87o8agp29o.fsf@evledraar.gmail.com/ 4. https://github.com/Perl/perl5/commit/7636ea95c57762930accf4358f7c0c2dec086b5e Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Acked-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-09-07tr2: do compiler enum check in trace2_collect_process_info()Libravatar Ævar Arnfjörð Bjarmason1-6/+7
Change code added in 2f732bf15e6 (tr2: log parent process name, 2021-07-21) to use a switch statement without a "default" branch to have the compiler error if this code ever drifts out of sync with the members of the "enum trace2_process_info_reason". Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Acked-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-09-07tr2: leave the parent list empty upon failure & don't leak memoryLibravatar Ævar Arnfjörð Bjarmason1-3/+5
In a subsequent commit I'll be replacing most of this code to log N parents, but let's first fix bugs introduced in the recent 2f732bf15e6 (tr2: log parent process name, 2021-07-21). It was using the strbuf_read_file() in the wrong way, its return value is either a length or a negative value on error. If we didn't have a procfs, or otherwise couldn't access it we'd end up pushing an empty string to the trace2 ancestry array. It was also using the strvec_push() API the wrong way. That API always does an xstrdup(), so by detaching the strbuf here we'd leak memory. Let's instead pass in our pointer for strvec_push() to xstrdup(), and then free our own strbuf. I do have some WIP changes to make strvec_push_nodup() non-static, which makes this and some other callsites nicer, but let's just follow the prevailing pattern of using strvec_push() for now. We'll also need to free that "procfs_path" strbuf whether or not strbuf_read_file() succeeds, which was another source of memory leaks in 2f732bf15e6, i.e. we'd leak that memory as well if we weren't on a system where we could read the file from procfs. Let's move all the freeing of the memory to the end of the function. If we're still at STRBUF_INIT with "name" due to not having taken the branch where the strbuf_read_file() succeeds freeing it is redundant. So we could move it into the body of the "if", but just handling freeing the same way for all branches of the function makes it more readable. In combination with the preceding commit this makes all of t[0-9]*trace2*.sh pass under SANITIZE=leak on Linux. Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Acked-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-09-07tr2: clarify TRACE2_PROCESS_INFO_EXIT comment under LinuxLibravatar Ævar Arnfjörð Bjarmason1-1/+5
Rewrite a comment added in 2f732bf15e6 (tr2: log parent process name, 2021-07-21) to describe what we might do under TRACE2_PROCESS_INFO_EXIT in the future, instead of vaguely referring to "something extra". Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Acked-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-09-07tr2: remove NEEDSWORK comment for "non-procfs" implementationsLibravatar Ævar Arnfjörð Bjarmason1-1/+0
I'm fairly sure that there is no way on Linux to inspect the process tree without using procfs, any tool such as ps(1), top(1) etc. that shows this sort of information ultimately looks the information up in procfs. So let's remove this comment added in 2f732bf15e6 (tr2: log parent process name, 2021-07-21), it's setting us up for an impossible task. Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Acked-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-09-03win32: allow building with pedantic mode enabledLibravatar Carlo Marcelo Arenas Belón2-2/+2
In preparation to building with pedantic mode enabled, change a couple of places where the current mingw gcc compiler provided with the SDK reports issues. A full fix for the incompatible use of (void *) to store function pointers has been punted, with the minimal change to instead use a generic function pointer (FARPROC), and therefore the (hopefully) temporary need to disable incompatible pointer warnings. Signed-off-by: Carlo Marcelo Arenas Belón <carenas@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-08-24Merge branch 'es/trace2-log-parent-process-name'Libravatar Junio C Hamano2-0/+66
trace2 logs learned to show parent process name to see in what context Git was invoked. * es/trace2-log-parent-process-name: tr2: log parent process name tr2: make process info collection platform-generic
2021-08-24compat: let git_mmap use malloc(3) directlyLibravatar René Scharfe1-1/+6
xmalloc() dies on error, allows zero-sized allocations and enforces GIT_ALLOC_LIMIT for testing. Our mmap replacement doesn't need any of that. Let's cut out the wrapper, reject zero-sized requests as required by POSIX and use malloc(3) directly. Allocation errors were needlessly handled by git_mmap() before; this code becomes reachable now. Signed-off-by: René Scharfe <l.s.r@web.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-08-02mingw: align symlinks-related rmdir() behavior with LinuxLibravatar Thomas Bétous1-0/+21
When performing a rebase, rmdir() is called on the folder .git/logs. On Unix rmdir() exits without deleting anything in case .git/logs is a symbolic link but the equivalent functions on Windows (_rmdir, _wrmdir and RemoveDirectoryW) do not behave the same and remove the folder if it is symlinked even if it is not empty. This creates issues when folders in .git/ are symlinks which is especially the case when git-repo[1] is used: It replaces `.git/logs/` with a symlink. One such issue is that the _target_ of that symlink is removed e.g. during a `git rebase`, where `delete_reflog("REBASE_HEAD")` will not only try to remove `.git/logs/REBASE_HEAD` but then recursively try to remove the parent directories until an error occurs, a technique that obviously relies on `rmdir()` refusing to remove a symlink. This was reported in https://github.com/git-for-windows/git/issues/2967. This commit updates mingw_rmdir() so that its behavior is the same as Linux rmdir() in case of symbolic links. To verify that Git does not regress on the reported issue, this patch adds a regression test for the `git rebase` symptom, even if the same `rmdir()` behavior is quite likely to cause potential problems in other Git commands as well. [1]: git-repo is a python tool built on top of Git which helps manage many Git repositories. It stores all the .git/ folders in a central place by taking advantage of symbolic links. More information: https://gerrit.googlesource.com/git-repo/ Signed-off-by: Thomas Bétous <tomspycell@gmail.com> Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-07-22tr2: log parent process nameLibravatar Emily Shaffer1-0/+55
It can be useful to tell who invoked Git - was it invoked manually by a user via CLI or script? By an IDE? In some cases - like 'repo' tool - we can influence the source code and set the GIT_TRACE2_PARENT_SID environment variable from the caller process. In 'repo''s case, that parent SID is manipulated to include the string "repo", which means we can positively identify when Git was invoked by 'repo' tool. However, identifying parents that way requires both that we know which tools invoke Git and that we have the ability to modify the source code of those tools. It cannot scale to keep up with the various IDEs and wrappers which use Git, most of which we don't know about. Learning which tools and wrappers invoke Git, and how, would give us insight to decide where to improve Git's usability and performance. Unfortunately, there's no cross-platform reliable way to gather the name of the parent process. If procfs is present, we can use that; otherwise we will need to discover the name another way. However, the process ID should be sufficient to look up the process name on most platforms, so that code may be shareable. Git for Windows gathers similar information and logs it as a "data_json" event. However, since "data_json" has a variable format, it is difficult to parse effectively in some languages; instead, let's pursue a dedicated "cmd_ancestry" event to record information about the ancestry of the current process and a consistent, parseable way. Git for Windows also gathers information about more than one generation of parent. In Linux further ancestry info can be gathered with procfs, but it's unwieldy to do so. In the interest of later moving Git for Windows ancestry logging to the 'cmd_ancestry' event, and in the interest of later adding more ancestry to the Linux implementation - or of adding this functionality to other platforms which have an easier time walking the process tree - let's make 'cmd_ancestry' accept an array of parentage. Signed-off-by: Emily Shaffer <emilyshaffer@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-07-22tr2: make process info collection platform-genericLibravatar Emily Shaffer1-0/+11
To pave the way for non-Windows platforms to define trace2_collect_process_info(), reorganize the stub-or-definition schema to something which doesn't directly reference Windows. Platforms which want to collect parent process information in the future should: 1. Add an implementation to compat/ (e.g. compat/somearch/procinfo.c) 2. Add that object to COMPAT_OBJS to config.mak.uname (e.g. COMPAT_OBJS += compat/somearch/procinfo.o) 3. Define HAVE_PLATFORM_PROCINFO in config.mak.uname In the Windows case, this definition lives in compat/win32/trace2_win32_process_info.c, which is already conditionally added to COMPAT_OBJS; so let's add HAVE_PLATFORM_PROCINFO to hint to the build that compat/stub/procinfo.c should not be used. Signed-off-by: Emily Shaffer <emilyshaffer@google.com> Helped-by: Jonathan Nieder <jrnieder@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-05-22Merge branch 'jh/simple-ipc-sans-pthread'Libravatar Junio C Hamano3-7/+19
The "simple-ipc" did not compile without pthreads support, but the build procedure was not properly account for it. * jh/simple-ipc-sans-pthread: simple-ipc: correct ifdefs when NO_PTHREADS is defined
2021-05-21simple-ipc: correct ifdefs when NO_PTHREADS is definedLibravatar Jeff Hostetler3-7/+19
Simple IPC always requires threads (in addition to various platform-specific IPC support). Fix the ifdefs in the Makefile to define SUPPORTS_SIMPLE_IPC when appropriate. Previously, the Unix version of the code would only verify that Unix domain sockets were available. This problem was reported here: https://lore.kernel.org/git/YKN5lXs4AoK%2FJFTO@coredump.intra.peff.net/T/#m08be8f1942ea8a2c36cfee0e51cdf06489fdeafc Reported-by: Randall S. Becker <rsbecker@nexbridge.com> Helped-by: Jeff King <peff@peff.net> Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-04-20Merge branch 'js/access-nul-emulation-on-windows'Libravatar Junio C Hamano1-0/+2
Portability fix. * js/access-nul-emulation-on-windows: msvc: avoid calling `access("NUL", flags)`
2021-04-16msvc: avoid calling `access("NUL", flags)`Libravatar Johannes Schindelin1-0/+2
Apparently this is not supported with Microsoft's Universal C Runtime. So let's not actually do that. Instead, just return success because we _know_ that we expect the `NUL` device to be present. Side note: it is possible to turn off the "Null device driver" and thereby disable `NUL`. Too many things are broken if this driver is disabled, therefore it is not worth bothering to try to detect its presence when `access()` is called. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-04-13Merge branch 'tb/precompose-prefix-simplify'Libravatar Junio C Hamano2-5/+5
Streamline the codepath to fix the UTF-8 encoding issues in the argv[] and the prefix on macOS. * tb/precompose-prefix-simplify: macOS: precompose startup_info->prefix precompose_utf8: make precompose_string_if_needed() public
2021-04-05precompose_utf8: make precompose_string_if_needed() publicLibravatar Torsten Bögershausen2-5/+5
commit 5c327502 (MacOS: precompose_argv_prefix(), 2021-02-03) uses the function precompose_string_if_needed() internally. It is only used from precompose_argv_prefix() and therefore static in compat/precompose_utf8.c Expose this function, it will be used in the next commit. While there, allow passing a NULL pointer, which will return NULL. Signed-off-by: Torsten Bögershausen <tboegi@web.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-04-02Merge branch 'jh/simple-ipc'Libravatar Junio C Hamano3-0/+1778
A simple IPC interface gets introduced to build services like fsmonitor on top. * jh/simple-ipc: t0052: add simple-ipc tests and t/helper/test-simple-ipc tool simple-ipc: add Unix domain socket implementation unix-stream-server: create unix domain socket under lock unix-socket: disallow chdir() when creating unix domain sockets unix-socket: add backlog size option to unix_stream_listen() unix-socket: eliminate static unix_stream_socket() helper function simple-ipc: add win32 implementation simple-ipc: design documentation for new IPC mechanism pkt-line: add options argument to read_packetized_to_strbuf() pkt-line: add PACKET_READ_GENTLE_ON_READ_ERROR option pkt-line: do not issue flush packets in write_packetized_*() pkt-line: eliminate the need for static buffer in packet_write_gently()
2021-03-22simple-ipc: add Unix domain socket implementationLibravatar Jeff Hostetler1-0/+999
Create Unix domain socket based implementation of "simple-ipc". A set of `ipc_client` routines implement a client library to connect to an `ipc_server` over a Unix domain socket, send a simple request, and receive a single response. Clients use blocking IO on the socket. A set of `ipc_server` routines implement a thread pool to listen for and concurrently service client connections. The server creates a new Unix domain socket at a known location. If a socket already exists with that name, the server tries to determine if another server is already listening on the socket or if the socket is dead. If socket is busy, the server exits with an error rather than stealing the socket. If the socket is dead, the server creates a new one and starts up. If while running, the server detects that its socket has been stolen by another server, it automatically exits. Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-03-15simple-ipc: add win32 implementationLibravatar Jeff Hostetler2-0/+779
Create Windows implementation of "simple-ipc" using named pipes. Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-03-08Sync with Git 2.30.2 for CVE-2021-21300Libravatar Junio C Hamano1-0/+2
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-03-04Merge branch 'jk/open-returns-eintr'Libravatar Junio C Hamano2-0/+26
Work around platforms whose open() is reported to return EINTR (it shouldn't, as we do our signals with SA_RESTART). * jk/open-returns-eintr: config.mak.uname: enable OPEN_RETURNS_EINTR for macOS Big Sur Makefile: add OPEN_RETURNS_EINTR knob
2021-02-26Makefile: add OPEN_RETURNS_EINTR knobLibravatar Jeff King2-0/+26
On some platforms, open() reportedly returns EINTR when opening regular files and we receive a signal (usually SIGALRM from our progress meter). This shouldn't happen, as open() should be a restartable syscall, and we specify SA_RESTART when setting up the alarm handler. So it may actually be a kernel or libc bug for this to happen. But it has been reported on at least one version of Linux (on a network filesystem): https://lore.kernel.org/git/c8061cce-71e4-17bd-a56a-a5fed93804da@neanderfunk.de/ as well as on macOS starting with Big Sur even on a regular filesystem. We can work around it by retrying open() calls that get EINTR, just as we do for read(), etc. Since we don't ever _want_ to interrupt an open() call, we can get away with just redefining open, rather than insisting all callsites use xopen(). We actually do have an xopen() wrapper already (and it even does this retry, though there's no indication of it being an observed problem back then; it seems simply to have been lifted from xread(), etc). But it is used hardly anywhere, and isn't suitable for general use because it will die() on error. In theory we could combine the two, but it's awkward to do so because of the variable-args interface of open(). This patch adds a Makefile knob for enabling the workaround. It's not enabled by default for any platforms in config.mak.uname yet, as we don't have enough data to decide how common this is (I have not been able to reproduce on either Linux or Big Sur myself). It may be worth enabling preemptively anyway, since the cost is pretty low (if we don't see an EINTR, it's just an extra conditional). However, note that we must not enable this on Windows. It doesn't do anything there, and the macro overrides the existing mingw_open() redirection. I've added a preemptive #undef here in the mingw header (which is processed first) to just quietly disable it (we could also make it an #error, but there is little point in being so aggressive). Reported-by: Aleksey Kliger <alklig@microsoft.com> Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-02-12Sync with 2.29.3Libravatar Johannes Schindelin1-0/+2
* maint-2.29: Git 2.29.3 Git 2.28.1 Git 2.27.1 Git 2.26.3 Git 2.25.5 Git 2.24.4 Git 2.23.4 Git 2.22.5 Git 2.21.4 Git 2.20.5 Git 2.19.6 Git 2.18.5 Git 2.17.6 unpack_trees(): start with a fresh lstat cache run-command: invalidate lstat cache after a command finished checkout: fix bug that makes checkout follow symlinks in leading path
2021-02-12Sync with 2.28.1Libravatar Johannes Schindelin1-0/+2
* maint-2.28: Git 2.28.1 Git 2.27.1 Git 2.26.3 Git 2.25.5 Git 2.24.4 Git 2.23.4 Git 2.22.5 Git 2.21.4 Git 2.20.5 Git 2.19.6 Git 2.18.5 Git 2.17.6 unpack_trees(): start with a fresh lstat cache run-command: invalidate lstat cache after a command finished checkout: fix bug that makes checkout follow symlinks in leading path
2021-02-12Sync with 2.27.1Libravatar Johannes Schindelin1-0/+2
* maint-2.27: Git 2.27.1 Git 2.26.3 Git 2.25.5 Git 2.24.4 Git 2.23.4 Git 2.22.5 Git 2.21.4 Git 2.20.5 Git 2.19.6 Git 2.18.5 Git 2.17.6 unpack_trees(): start with a fresh lstat cache run-command: invalidate lstat cache after a command finished checkout: fix bug that makes checkout follow symlinks in leading path
2021-02-12Sync with 2.26.3Libravatar Johannes Schindelin1-0/+2
* maint-2.26: Git 2.26.3 Git 2.25.5 Git 2.24.4 Git 2.23.4 Git 2.22.5 Git 2.21.4 Git 2.20.5 Git 2.19.6 Git 2.18.5 Git 2.17.6 unpack_trees(): start with a fresh lstat cache run-command: invalidate lstat cache after a command finished checkout: fix bug that makes checkout follow symlinks in leading path
2021-02-12Sync with 2.25.5Libravatar Johannes Schindelin1-0/+2
* maint-2.25: Git 2.25.5 Git 2.24.4 Git 2.23.4 Git 2.22.5 Git 2.21.4 Git 2.20.5 Git 2.19.6 Git 2.18.5 Git 2.17.6 unpack_trees(): start with a fresh lstat cache run-command: invalidate lstat cache after a command finished checkout: fix bug that makes checkout follow symlinks in leading path
2021-02-12Sync with 2.24.4Libravatar Johannes Schindelin1-0/+2
* maint-2.24: Git 2.24.4 Git 2.23.4 Git 2.22.5 Git 2.21.4 Git 2.20.5 Git 2.19.6 Git 2.18.5 Git 2.17.6 unpack_trees(): start with a fresh lstat cache run-command: invalidate lstat cache after a command finished checkout: fix bug that makes checkout follow symlinks in leading path
2021-02-12Sync with 2.23.4Libravatar Johannes Schindelin1-0/+2
* maint-2.23: Git 2.23.4 Git 2.22.5 Git 2.21.4 Git 2.20.5 Git 2.19.6 Git 2.18.5 Git 2.17.6 unpack_trees(): start with a fresh lstat cache run-command: invalidate lstat cache after a command finished checkout: fix bug that makes checkout follow symlinks in leading path
2021-02-12Sync with 2.22.5Libravatar Johannes Schindelin1-0/+2
* maint-2.22: Git 2.22.5 Git 2.21.4 Git 2.20.5 Git 2.19.6 Git 2.18.5 Git 2.17.6 unpack_trees(): start with a fresh lstat cache run-command: invalidate lstat cache after a command finished checkout: fix bug that makes checkout follow symlinks in leading path
2021-02-12Sync with 2.21.4Libravatar Johannes Schindelin1-0/+2
* maint-2.21: Git 2.21.4 Git 2.20.5 Git 2.19.6 Git 2.18.5 Git 2.17.6 unpack_trees(): start with a fresh lstat cache run-command: invalidate lstat cache after a command finished checkout: fix bug that makes checkout follow symlinks in leading path
2021-02-12Sync with 2.20.5Libravatar Johannes Schindelin1-0/+2
* maint-2.20: Git 2.20.5 Git 2.19.6 Git 2.18.5 Git 2.17.6 unpack_trees(): start with a fresh lstat cache run-command: invalidate lstat cache after a command finished checkout: fix bug that makes checkout follow symlinks in leading path
2021-02-12Sync with 2.19.6Libravatar Johannes Schindelin1-0/+2
* maint-2.19: Git 2.19.6 Git 2.18.5 Git 2.17.6 unpack_trees(): start with a fresh lstat cache run-command: invalidate lstat cache after a command finished checkout: fix bug that makes checkout follow symlinks in leading path
2021-02-12Sync with 2.18.5Libravatar Johannes Schindelin1-0/+2
* maint-2.18: Git 2.18.5 Git 2.17.6 unpack_trees(): start with a fresh lstat cache run-command: invalidate lstat cache after a command finished checkout: fix bug that makes checkout follow symlinks in leading path
2021-02-12Sync with 2.17.6Libravatar Johannes Schindelin1-0/+2
* maint-2.17: Git 2.17.6 unpack_trees(): start with a fresh lstat cache run-command: invalidate lstat cache after a command finished checkout: fix bug that makes checkout follow symlinks in leading path
2021-02-12checkout: fix bug that makes checkout follow symlinks in leading pathLibravatar Matheus Tavares1-0/+2
Before checking out a file, we have to confirm that all of its leading components are real existing directories. And to reduce the number of lstat() calls in this process, we cache the last leading path known to contain only directories. However, when a path collision occurs (e.g. when checking out case-sensitive files in case-insensitive file systems), a cached path might have its file type changed on disk, leaving the cache on an invalid state. Normally, this doesn't bring any bad consequences as we usually check out files in index order, and therefore, by the time the cached path becomes outdated, we no longer need it anyway (because all files in that directory would have already been written). But, there are some users of the checkout machinery that do not always follow the index order. In particular: checkout-index writes the paths in the same order that they appear on the CLI (or stdin); and the delayed checkout feature -- used when a long-running filter process replies with "status=delayed" -- postpones the checkout of some entries, thus modifying the checkout order. When we have to check out an out-of-order entry and the lstat() cache is invalid (due to a previous path collision), checkout_entry() may end up using the invalid data and thrusting that the leading components are real directories when, in reality, they are not. In the best case scenario, where the directory was replaced by a regular file, the user will get an error: "fatal: unable to create file 'foo/bar': Not a directory". But if the directory was replaced by a symlink, checkout could actually end up following the symlink and writing the file at a wrong place, even outside the repository. Since delayed checkout is affected by this bug, it could be used by an attacker to write arbitrary files during the clone of a maliciously crafted repository. Some candidate solutions considered were to disable the lstat() cache during unordered checkouts or sort the entries before passing them to the checkout machinery. But both ideas include some performance penalty and they don't future-proof the code against new unordered use cases. Instead, we now manually reset the lstat cache whenever we successfully remove a directory. Note: We are not even checking whether the directory was the same as the lstat cache points to because we might face a scenario where the paths refer to the same location but differ due to case folding, precomposed UTF-8 issues, or the presence of `..` components in the path. Two regression tests, with case-collisions and utf8-collisions, are also added for both checkout-index and delayed checkout. Note: to make the previously mentioned clone attack unfeasible, it would be sufficient to reset the lstat cache only after the remove_subtree() call inside checkout_entry(). This is the place where we would remove a directory whose path collides with the path of another entry that we are currently trying to check out (possibly a symlink). However, in the interest of a thorough fix that does not leave Git open to similar-but-not-identical attack vectors, we decided to intercept all `rmdir()` calls in one fell swoop. This addresses CVE-2021-21300. Co-authored-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Matheus Tavares <matheus.bernardino@usp.br>
2021-02-03MacOS: precompose_argv_prefix()Libravatar Torsten Bögershausen2-20/+34
The following sequence leads to a "BUG" assertion running under MacOS: DIR=git-test-restore-p Adiarnfd=$(printf 'A\314\210') DIRNAME=xx${Adiarnfd}yy mkdir $DIR && cd $DIR && git init && mkdir $DIRNAME && cd $DIRNAME && echo "Initial" >file && git add file && echo "One more line" >>file && echo y | git restore -p . Initialized empty Git repository in /tmp/git-test-restore-p/.git/ BUG: pathspec.c:495: error initializing pathspec_item Cannot close git diff-index --cached --numstat [snip] The command `git restore` is run from a directory inside a Git repo. Git needs to split the $CWD into 2 parts: The path to the repo and "the rest", if any. "The rest" becomes a "prefix" later used inside the pathspec code. As an example, "/path/to/repo/dir-inside-repå" would determine "/path/to/repo" as the root of the repo, the place where the configuration file .git/config is found. The rest becomes the prefix ("dir-inside-repå"), from where the pathspec machinery expands the ".", more about this later. If there is a decomposed form, (making the decomposing visible like this), "dir-inside-rep°a" doesn't match "dir-inside-repå". Git commands need to: (a) read the configuration variable "core.precomposeunicode" (b) precocompose argv[] (c) precompose the prefix, if there was any The first commit, 76759c7dff53 "git on Mac OS and precomposed unicode" addressed (a) and (b). The call to precompose_argv() was added into parse-options.c, because that seemed to be a good place when the patch was written. Commands that don't use parse-options need to do (a) and (b) themselfs. The commands `diff-files`, `diff-index`, `diff-tree` and `diff` learned (a) and (b) in commit 90a78b83e0b8 "diff: run arguments through precompose_argv" Branch names (or refs in general) using decomposed code points resulting in decomposed file names had been fixed in commit 8e712ef6fc97 "Honor core.precomposeUnicode in more places" The bug report from above shows 2 things: - more commands need to handle precomposed unicode - (c) should be implemented for all commands using pathspecs Solution: precompose_argv() now handles the prefix (if needed), and is renamed into precompose_argv_prefix(). Inside this function the config variable core.precomposeunicode is read into the global variable precomposed_unicode, as before. This reading is skipped if precomposed_unicode had been read before. The original patch for preocomposed unicode, 76759c7dff53, placed precompose_argv() into parse-options.c Now add it into git.c::run_builtin() as well. Existing precompose calls in diff-files.c and others may become redundant, and if we audit the callflows that reach these places to make sure that they can never be reached without going through the new call added to run_builtin(), we might be able to remove these existing ones. But in this commit, we do not bother to do so and leave these precompose callsites as they are. Because precompose() is idempotent and can be called on an already precomposed string safely, this is safer than removing existing calls without fully vetting the callflows. There is certainly room for cleanups - this change intends to be a bug fix. Cleanups needs more tests in e.g. t/t3910-mac-os-precompose.sh, and should be done in future commits. [1] git-bugreport-2021-01-06-1209.txt (git can't deal with special characters) [2] https://lore.kernel.org/git/A102844A-9501-4A86-854D-E3B387D378AA@icloud.com/ Reported-by: Daniel Troger <random_n0body@icloud.com> Helped-By: Philippe Blain <levraiphilippeblain@gmail.com> Signed-off-by: Torsten Bögershausen <tboegi@web.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-12-14Merge branch 'da/vs-build-iconv-fix'Libravatar Junio C Hamano1-1/+1
Build update. * da/vs-build-iconv-fix: ci(vs-build): stop passing the iconv library location explicitly