fixup string comparison #7

nalla · 2015-03-03T14:07:02Z

Signed-off-by: nalla nalla@users.noreply.github.com

Signed-off-by: nalla <nalla@users.noreply.github.com>

buildhive · 2015-03-03T14:18:25Z

dscho » git #110 FAILURE
Looks like there's a problem with this pull request
(what's this?)

buildhive · 2015-03-03T14:30:07Z

dscho » git #111 FAILURE
Looks like there's a problem with this pull request
(what's this?)

nalla · 2015-03-03T14:51:00Z

Ok. Sounds good.

dscho · 2015-03-03T15:15:56Z

@nalla thank you for testing, and also for pointing out my mistake. This makes Git for Windows better!

Signed-off-by: Junio C Hamano <gitster@pobox.com>

We turn off ASan's leak detection by default in the test suite because it's too noisy. But we don't do so until part-way through test-lib. This is before we've run any tests, but after we do our initial "./git" to see if the binary has even been built. When built with clang, this seems to work fine. However, using "gcc -fsanitize=address", the leak checker seems to complain more aggressively: $ ./git ... ==5352==ERROR: LeakSanitizer: detected memory leaks Direct leak of 2 byte(s) in 1 object(s) allocated from: #0 0x7f120e7afcf8 in malloc (/usr/lib/x86_64-linux-gnu/libasan.so.3+0xc1cf8) #1 0x559fc2a3ce41 in do_xmalloc /home/peff/compile/git/wrapper.c:60 #2 0x559fc2a3cf1a in do_xmallocz /home/peff/compile/git/wrapper.c:100 #3 0x559fc2a3d0ad in xmallocz /home/peff/compile/git/wrapper.c:108 #4 0x559fc2a3d0ad in xmemdupz /home/peff/compile/git/wrapper.c:124 #5 0x559fc2a3d0ad in xstrndup /home/peff/compile/git/wrapper.c:130 #6 0x559fc274535a in main /home/peff/compile/git/common-main.c:39 #7 0x7f120dabd2b0 in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x202b0) This is a leak in the sense that we never free it, but it's in a global that is meant to last the whole program. So it's not really interesting or in need of fixing. And at any rate, mentioning leaks outside of the test_expect blocks is certainly unwelcome, as it pollutes stderr. Let's bump the setting of ASAN_OPTIONS higher in test-lib.sh to catch our initial "can we even run git?" test. While we're at it, we can add a comment to make it a bit less inscrutable. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>

This is to address concerns raised by ThreadSanitizer on the mailing list about threaded unprotected R/W access to map.size with my previous "disallow rehash" change (0607e10). See: https://public-inbox.org/git/adb37b70139fd1e2bac18bfd22c8b96683ae18eb.1502780344.git.martin.agren@gmail.com/ Add API to hashmap to disable item counting and thus automatic rehashing. Also include API to later re-enable them. When item counting is disabled, the map.size field is invalid. So to prevent accidents, the field has been renamed and an accessor function hashmap_get_size() has been added. All direct references to this field have been been updated. And the name of the field changed to map.private_size to communicate this. Here is the relevant output from ThreadSanitizer showing the problem: WARNING: ThreadSanitizer: data race (pid=10554) Read of size 4 at 0x00000082d488 by thread T2 (mutexes: write M16): #0 hashmap_add hashmap.c:209 #1 hash_dir_entry_with_parent_and_prefix name-hash.c:302 #2 handle_range_dir name-hash.c:347 #3 handle_range_1 name-hash.c:415 #4 lazy_dir_thread_proc name-hash.c:471 #5 <null> <null> Previous write of size 4 at 0x00000082d488 by thread T1 (mutexes: write M31): #0 hashmap_add hashmap.c:209 #1 hash_dir_entry_with_parent_and_prefix name-hash.c:302 #2 handle_range_dir name-hash.c:347 #3 handle_range_1 name-hash.c:415 #4 handle_range_dir name-hash.c:380 #5 handle_range_1 name-hash.c:415 #6 lazy_dir_thread_proc name-hash.c:471 #7 <null> <null> Martin gives instructions for running TSan on test t3008 in this post: https://public-inbox.org/git/CAN0heSoJDL9pWELD6ciLTmWf-a=oyxe4EXXOmCKvsG5MSuzxsA@mail.gmail.com/ Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Completely convert the pathname expoted in the %msvc_bin_dir_msys% variable to MSYS format with forward slashes rather than a mixture of forward and back slashes. This solves an obscure problem observed by some developers: [...] http-push.c CC remote-curl.o remote-curl.c * new script parameters GEN git-instaweb sed: -e expression #7, char 155: invalid reference \2 on `s' command's RHS make: *** [Makefile:2023: git-instaweb] Error 1 Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>

Dependencies such as cURL and OpenSSL are necessary to build and run Git. Previously, we obtained those dependencies by fetching NuGet packages. However, it is notoriously hard to keep NuGet packages of C/C++ libraries up-to-date, as the toolsets for different Visual Studio versions are different, and the NuGet packages would have to ship them all. That is the reason why the NuGet packages we use are quite old, and even insecure in the case of cURL and OpenSSL (the versions contain known security flaws that have been addressed by later versions for which no NuGet packages are available). The better way to handle this situation is to use the vcpkg system: https://github.com/Microsoft/vcpkg The idea is that a single Git repository contains enough supporting files to build up-to-date versions of a large number of Open Source libraries on demand, including cURL and OpenSSL. We integrate this system via four new .bat files to 1) initialize the vcpkg system, 2) build the packages, 4) set up Git's Makefile system to find the build artifacts, and 3) copy the artifacts into the top-level directory We now also completely convert the pathname exported in the %msvc_bin_dir_msys% variable to MSYS format with forward slashes rather than a mixture of forward and back slashes. This solves an obscure problem observed by some developers: [...] http-push.c CC remote-curl.o remote-curl.c * new script parameters GEN git-instaweb sed: -e expression #7, char 155: invalid reference \2 on `s' command's RHS make: *** [Makefile:2023: git-instaweb] Error 1 Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com> Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>

status: deserialization wait

write_commit_graph initialises topo_levels using init_topo_level_slab(), next it calls compute_topological_levels() which can cause the slab to grow, we therefore need to clear the slab again using clear_topo_level_slab() when we're done. First introduced in 72a2bfc (commit-graph: add a slab to store topological levels, 2021-01-16). LeakSanitizer output: ==1026==ERROR: LeakSanitizer: detected memory leaks Direct leak of 8 byte(s) in 1 object(s) allocated from: #0 0x498ae9 in realloc /src/llvm-project/compiler-rt/lib/asan/asan_malloc_linux.cpp:164:3 #1 0xafbed8 in xrealloc /src/git/wrapper.c:126:8 #2 0x7966d1 in topo_level_slab_at_peek /src/git/commit-graph.c:71:1 #3 0x7965e0 in topo_level_slab_at /src/git/commit-graph.c:71:1 #4 0x78fbf5 in compute_topological_levels /src/git/commit-graph.c:1472:12 #5 0x78c5c3 in write_commit_graph /src/git/commit-graph.c:2456:2 #6 0x535c5f in graph_write /src/git/builtin/commit-graph.c:299:6 #7 0x5350ca in cmd_commit_graph /src/git/builtin/commit-graph.c:337:11 #8 0x4cddb1 in run_builtin /src/git/git.c:453:11 #9 0x4cabe2 in handle_builtin /src/git/git.c:704:3 #10 0x4cd084 in run_argv /src/git/git.c:771:4 #11 0x4ca424 in cmd_main /src/git/git.c:902:19 #12 0x707fb6 in main /src/git/common-main.c:52:11 #13 0x7fee4249383f in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2083f) Indirect leak of 524256 byte(s) in 1 object(s) allocated from: #0 0x498942 in calloc /src/llvm-project/compiler-rt/lib/asan/asan_malloc_linux.cpp:154:3 #1 0xafc088 in xcalloc /src/git/wrapper.c:140:8 #2 0x796870 in topo_level_slab_at_peek /src/git/commit-graph.c:71:1 #3 0x7965e0 in topo_level_slab_at /src/git/commit-graph.c:71:1 #4 0x78fbf5 in compute_topological_levels /src/git/commit-graph.c:1472:12 #5 0x78c5c3 in write_commit_graph /src/git/commit-graph.c:2456:2 #6 0x535c5f in graph_write /src/git/builtin/commit-graph.c:299:6 #7 0x5350ca in cmd_commit_graph /src/git/builtin/commit-graph.c:337:11 #8 0x4cddb1 in run_builtin /src/git/git.c:453:11 #9 0x4cabe2 in handle_builtin /src/git/git.c:704:3 #10 0x4cd084 in run_argv /src/git/git.c:771:4 #11 0x4ca424 in cmd_main /src/git/git.c:902:19 #12 0x707fb6 in main /src/git/common-main.c:52:11 #13 0x7fee4249383f in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2083f) SUMMARY: AddressSanitizer: 524264 byte(s) leaked in 2 allocation(s). Signed-off-by: Andrzej Hunt <ajrhunt@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>

In a sparse index it is possible for the tree that is being verified to be freed while it is being verified. This happens when the index is sparse but the cache tree is not and index_name_pos() looks up a path from the cache tree that is a descendant of a sparse index entry. That triggers a call to ensure_full_index() which frees the cache tree that is being verified. Carrying on trying to verify the tree after this results in a use-after-free bug. Instead restart the verification if a sparse index is converted to a full index. This bug is triggered by a call to reset_head() in "git rebase --apply". Thanks to RenÃ© Scharfe and Derrick Stolee for their help analyzing the problem. ==74345==ERROR: AddressSanitizer: heap-use-after-free on address 0x606000001b20 at pc 0x557cbe82d3a2 bp 0x7ffdfee08090 sp 0x7ffdfee08080 READ of size 4 at 0x606000001b20 thread T0 #0 0x557cbe82d3a1 in verify_one /home/phil/src/git/cache-tree.c:863 #1 0x557cbe82ca9d in verify_one /home/phil/src/git/cache-tree.c:840 #2 0x557cbe82ca9d in verify_one /home/phil/src/git/cache-tree.c:840 #3 0x557cbe82ca9d in verify_one /home/phil/src/git/cache-tree.c:840 #4 0x557cbe830a2b in cache_tree_verify /home/phil/src/git/cache-tree.c:910 #5 0x557cbea53741 in write_locked_index /home/phil/src/git/read-cache.c:3250 #6 0x557cbeab7fdd in reset_head /home/phil/src/git/reset.c:87 #7 0x557cbe72147f in cmd_rebase builtin/rebase.c:2074 #8 0x557cbe5bd151 in run_builtin /home/phil/src/git/git.c:461 #9 0x557cbe5bd151 in handle_builtin /home/phil/src/git/git.c:714 #10 0x557cbe5c0503 in run_argv /home/phil/src/git/git.c:781 #11 0x557cbe5c0503 in cmd_main /home/phil/src/git/git.c:912 #12 0x557cbe5bad28 in main /home/phil/src/git/common-main.c:52 #13 0x7fdd4b82eb24 in __libc_start_main (/usr/lib/libc.so.6+0x27b24) #14 0x557cbe5bcb8d in _start (/home/phil/src/git/git+0x1b9b8d) 0x606000001b20 is located 0 bytes inside of 56-byte region [0x606000001b20,0x606000001b58) freed by thread T0 here: #0 0x7fdd4bacff19 in __interceptor_free /build/gcc/src/gcc/libsanitizer/asan/asan_malloc_linux.cpp:127 #1 0x557cbe82af60 in cache_tree_free /home/phil/src/git/cache-tree.c:35 #2 0x557cbe82aee5 in cache_tree_free /home/phil/src/git/cache-tree.c:31 #3 0x557cbe82aee5 in cache_tree_free /home/phil/src/git/cache-tree.c:31 #4 0x557cbe82aee5 in cache_tree_free /home/phil/src/git/cache-tree.c:31 #5 0x557cbeb2557a in ensure_full_index /home/phil/src/git/sparse-index.c:310 #6 0x557cbea45c4a in index_name_stage_pos /home/phil/src/git/read-cache.c:588 #7 0x557cbe82ce37 in verify_one /home/phil/src/git/cache-tree.c:850 #8 0x557cbe82ca9d in verify_one /home/phil/src/git/cache-tree.c:840 #9 0x557cbe82ca9d in verify_one /home/phil/src/git/cache-tree.c:840 #10 0x557cbe82ca9d in verify_one /home/phil/src/git/cache-tree.c:840 #11 0x557cbe830a2b in cache_tree_verify /home/phil/src/git/cache-tree.c:910 #12 0x557cbea53741 in write_locked_index /home/phil/src/git/read-cache.c:3250 #13 0x557cbeab7fdd in reset_head /home/phil/src/git/reset.c:87 #14 0x557cbe72147f in cmd_rebase builtin/rebase.c:2074 #15 0x557cbe5bd151 in run_builtin /home/phil/src/git/git.c:461 #16 0x557cbe5bd151 in handle_builtin /home/phil/src/git/git.c:714 #17 0x557cbe5c0503 in run_argv /home/phil/src/git/git.c:781 #18 0x557cbe5c0503 in cmd_main /home/phil/src/git/git.c:912 #19 0x557cbe5bad28 in main /home/phil/src/git/common-main.c:52 #20 0x7fdd4b82eb24 in __libc_start_main (/usr/lib/libc.so.6+0x27b24) previously allocated by thread T0 here: #0 0x7fdd4bad0459 in __interceptor_calloc /build/gcc/src/gcc/libsanitizer/asan/asan_malloc_linux.cpp:154 #1 0x557cbebc1807 in xcalloc /home/phil/src/git/wrapper.c:140 #2 0x557cbe82b7d8 in cache_tree /home/phil/src/git/cache-tree.c:17 #3 0x557cbe82b7d8 in prime_cache_tree_rec /home/phil/src/git/cache-tree.c:763 #4 0x557cbe82b837 in prime_cache_tree_rec /home/phil/src/git/cache-tree.c:764 #5 0x557cbe82b837 in prime_cache_tree_rec /home/phil/src/git/cache-tree.c:764 #6 0x557cbe8304e1 in prime_cache_tree /home/phil/src/git/cache-tree.c:779 #7 0x557cbeab7fa7 in reset_head /home/phil/src/git/reset.c:85 #8 0x557cbe72147f in cmd_rebase builtin/rebase.c:2074 #9 0x557cbe5bd151 in run_builtin /home/phil/src/git/git.c:461 #10 0x557cbe5bd151 in handle_builtin /home/phil/src/git/git.c:714 #11 0x557cbe5c0503 in run_argv /home/phil/src/git/git.c:781 #12 0x557cbe5c0503 in cmd_main /home/phil/src/git/git.c:912 #13 0x557cbe5bad28 in main /home/phil/src/git/common-main.c:52 #14 0x7fdd4b82eb24 in __libc_start_main (/usr/lib/libc.so.6+0x27b24) Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk> Signed-off-by: Derrick Stolee <dstolee@microsoft.com>

When I was playing around with trace2 data and creating flamegraphs, I tried a `git fetch` call to see how the `git-remote-https` command would show up. What I didn't expect was an `ensure_full_index()` region! It turns out that `git fetch` and `git pull` need to check the index for a `.gitmodules` file to see if it should recurse into any submodules. Here is the stack trace from a debugger: ``` #0 ensure_full_index (istate=0x555555ac1c80 <the_index>) at sparse-index.c:404 #1 0x000055555571a979 in do_read_index (istate=istate@entry=0x555555ac1c80 <the_index>, path=path@entry=0x555555ad7b90 ".git/index", must_exist=must_exist@entry=0) at read-cache.c:2386 #2 0x000055555571eb7d in do_read_index (must_exist=0, path=0x555555ad7b90 ".git/index", istate=0x555555ac1c80 <the_index>) at hash.h:244 #3 read_index_from (istate=0x555555ac1c80 <the_index>, path=0x555555ad7b90 ".git/index", gitdir=0x555555ad7b30 ".git") at read-cache.c:2426 #4 0x000055555573f4c2 in repo_read_index (repo=repo@entry=0x555555ac1da0 <the_repo>) at repository.c:286 #5 0x00005555556f14d0 in get_oid_with_context_1 (repo=repo@entry=0x555555ac1da0 <the_repo>, name=name@entry=0x55555582c022 ":.gitmodules", flags=flags@entry=0, prefix=prefix@entry=0x0, oid=oid@entry=0x7fffffffdb00, oc=oc@entry=0x7fffffffda70) at object-name.c:1850 #6 0x00005555556f1f53 in get_oid_with_context (oc=0x7fffffffda70, oid=0x7fffffffdb00, flags=0, str=0x55555582c022 ":.gitmodules", repo=0x555555ac1da0 <the_repo>) at object-name.c:1947 #7 repo_get_oid (r=r@entry=0x555555ac1da0 <the_repo>, name=name@entry=0x55555582c022 ":.gitmodules", oid=oid@entry=0x7fffffffdb00) at object-name.c:1603 #8 0x000055555577330f in config_from_gitmodules (fn=fn@entry=0x555555773460 <gitmodules_fetch_config>, repo=0x555555ac1da0 <the_repo>, data=data@entry=0x7fffffffdb60) at submodule-config.c:650 #9 0x000055555577462d in config_from_gitmodules (data=0x7fffffffdb60, repo=<optimized out>, fn=0x555555773460 <gitmodules_fetch_config>) at submodule-config.c:638 #10 fetch_config_from_gitmodules (max_children=<optimized out>, recurse_submodules=<optimized out>) at submodule-config.c:800 #11 0x00005555555b9e41 in cmd_fetch (argc=1, argv=0x7fffffffe090, prefix=0x0) at builtin/fetch.c:1999 #12 0x0000555555573ff6 in run_builtin (argv=<optimized out>, argc=<optimized out>, p=<optimized out>) at git.c:528 #13 handle_builtin (argc=<optimized out>, argv=<optimized out>) at git.c:785 #14 0x000055555557528c in run_argv (argv=0x7fffffffddf0, argcp=0x7fffffffddfc) at git.c:857 #15 cmd_main (argc=<optimized out>, argv=<optimized out>) at git.c:993 #16 0x0000555555573ac8 in main (argc=3, argv=0x7fffffffe088) at common-main.c:52 ``` The operations these commands use are guarded by items such as `index_name_pos()` and others. Since the `.gitmodules` file is always at root, we would not need to expand, anyway.

In a sparse index it is possible for the tree that is being verified to be freed while it is being verified. This happens when the index is sparse but the cache tree is not and index_name_pos() looks up a path from the cache tree that is a descendant of a sparse index entry. That triggers a call to ensure_full_index() which frees the cache tree that is being verified. Carrying on trying to verify the tree after this results in a use-after-free bug. Instead restart the verification if a sparse index is converted to a full index. This bug is triggered by a call to reset_head() in "git rebase --apply". Thanks to René Scharfe and Derrick Stolee for their help analyzing the problem. ==74345==ERROR: AddressSanitizer: heap-use-after-free on address 0x606000001b20 at pc 0x557cbe82d3a2 bp 0x7ffdfee08090 sp 0x7ffdfee08080 READ of size 4 at 0x606000001b20 thread T0 #0 0x557cbe82d3a1 in verify_one /home/phil/src/git/cache-tree.c:863 #1 0x557cbe82ca9d in verify_one /home/phil/src/git/cache-tree.c:840 #2 0x557cbe82ca9d in verify_one /home/phil/src/git/cache-tree.c:840 #3 0x557cbe82ca9d in verify_one /home/phil/src/git/cache-tree.c:840 #4 0x557cbe830a2b in cache_tree_verify /home/phil/src/git/cache-tree.c:910 #5 0x557cbea53741 in write_locked_index /home/phil/src/git/read-cache.c:3250 #6 0x557cbeab7fdd in reset_head /home/phil/src/git/reset.c:87 #7 0x557cbe72147f in cmd_rebase builtin/rebase.c:2074 #8 0x557cbe5bd151 in run_builtin /home/phil/src/git/git.c:461 #9 0x557cbe5bd151 in handle_builtin /home/phil/src/git/git.c:714 #10 0x557cbe5c0503 in run_argv /home/phil/src/git/git.c:781 #11 0x557cbe5c0503 in cmd_main /home/phil/src/git/git.c:912 #12 0x557cbe5bad28 in main /home/phil/src/git/common-main.c:52 #13 0x7fdd4b82eb24 in __libc_start_main (/usr/lib/libc.so.6+0x27b24) #14 0x557cbe5bcb8d in _start (/home/phil/src/git/git+0x1b9b8d) 0x606000001b20 is located 0 bytes inside of 56-byte region [0x606000001b20,0x606000001b58) freed by thread T0 here: #0 0x7fdd4bacff19 in __interceptor_free /build/gcc/src/gcc/libsanitizer/asan/asan_malloc_linux.cpp:127 #1 0x557cbe82af60 in cache_tree_free /home/phil/src/git/cache-tree.c:35 #2 0x557cbe82aee5 in cache_tree_free /home/phil/src/git/cache-tree.c:31 #3 0x557cbe82aee5 in cache_tree_free /home/phil/src/git/cache-tree.c:31 #4 0x557cbe82aee5 in cache_tree_free /home/phil/src/git/cache-tree.c:31 #5 0x557cbeb2557a in ensure_full_index /home/phil/src/git/sparse-index.c:310 #6 0x557cbea45c4a in index_name_stage_pos /home/phil/src/git/read-cache.c:588 #7 0x557cbe82ce37 in verify_one /home/phil/src/git/cache-tree.c:850 #8 0x557cbe82ca9d in verify_one /home/phil/src/git/cache-tree.c:840 #9 0x557cbe82ca9d in verify_one /home/phil/src/git/cache-tree.c:840 #10 0x557cbe82ca9d in verify_one /home/phil/src/git/cache-tree.c:840 #11 0x557cbe830a2b in cache_tree_verify /home/phil/src/git/cache-tree.c:910 #12 0x557cbea53741 in write_locked_index /home/phil/src/git/read-cache.c:3250 #13 0x557cbeab7fdd in reset_head /home/phil/src/git/reset.c:87 #14 0x557cbe72147f in cmd_rebase builtin/rebase.c:2074 #15 0x557cbe5bd151 in run_builtin /home/phil/src/git/git.c:461 #16 0x557cbe5bd151 in handle_builtin /home/phil/src/git/git.c:714 #17 0x557cbe5c0503 in run_argv /home/phil/src/git/git.c:781 #18 0x557cbe5c0503 in cmd_main /home/phil/src/git/git.c:912 #19 0x557cbe5bad28 in main /home/phil/src/git/common-main.c:52 #20 0x7fdd4b82eb24 in __libc_start_main (/usr/lib/libc.so.6+0x27b24) previously allocated by thread T0 here: #0 0x7fdd4bad0459 in __interceptor_calloc /build/gcc/src/gcc/libsanitizer/asan/asan_malloc_linux.cpp:154 #1 0x557cbebc1807 in xcalloc /home/phil/src/git/wrapper.c:140 #2 0x557cbe82b7d8 in cache_tree /home/phil/src/git/cache-tree.c:17 #3 0x557cbe82b7d8 in prime_cache_tree_rec /home/phil/src/git/cache-tree.c:763 #4 0x557cbe82b837 in prime_cache_tree_rec /home/phil/src/git/cache-tree.c:764 #5 0x557cbe82b837 in prime_cache_tree_rec /home/phil/src/git/cache-tree.c:764 #6 0x557cbe8304e1 in prime_cache_tree /home/phil/src/git/cache-tree.c:779 #7 0x557cbeab7fa7 in reset_head /home/phil/src/git/reset.c:85 #8 0x557cbe72147f in cmd_rebase builtin/rebase.c:2074 #9 0x557cbe5bd151 in run_builtin /home/phil/src/git/git.c:461 #10 0x557cbe5bd151 in handle_builtin /home/phil/src/git/git.c:714 #11 0x557cbe5c0503 in run_argv /home/phil/src/git/git.c:781 #12 0x557cbe5c0503 in cmd_main /home/phil/src/git/git.c:912 #13 0x557cbe5bad28 in main /home/phil/src/git/common-main.c:52 #14 0x7fdd4b82eb24 in __libc_start_main (/usr/lib/libc.so.6+0x27b24) Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk> Signed-off-by: Junio C Hamano <gitster@pobox.com>

When I was playing around with trace2 data and creating flamegraphs, I tried a `git fetch` call to see how the `git-remote-https` command would show up. What I didn't expect was an `ensure_full_index()` region! It turns out that `git fetch` and `git pull` need to check the index for a `.gitmodules` file to see if it should recurse into any submodules. Here is the stack trace from a debugger: ``` #0 ensure_full_index (istate=0x555555ac1c80 <the_index>) at sparse-index.c:404 #1 0x000055555571a979 in do_read_index (istate=istate@entry=0x555555ac1c80 <the_index>, path=path@entry=0x555555ad7b90 ".git/index", must_exist=must_exist@entry=0) at read-cache.c:2386 #2 0x000055555571eb7d in do_read_index (must_exist=0, path=0x555555ad7b90 ".git/index", istate=0x555555ac1c80 <the_index>) at hash.h:244 #3 read_index_from (istate=0x555555ac1c80 <the_index>, path=0x555555ad7b90 ".git/index", gitdir=0x555555ad7b30 ".git") at read-cache.c:2426 #4 0x000055555573f4c2 in repo_read_index (repo=repo@entry=0x555555ac1da0 <the_repo>) at repository.c:286 #5 0x00005555556f14d0 in get_oid_with_context_1 (repo=repo@entry=0x555555ac1da0 <the_repo>, name=name@entry=0x55555582c022 ":.gitmodules", flags=flags@entry=0, prefix=prefix@entry=0x0, oid=oid@entry=0x7fffffffdb00, oc=oc@entry=0x7fffffffda70) at object-name.c:1850 #6 0x00005555556f1f53 in get_oid_with_context (oc=0x7fffffffda70, oid=0x7fffffffdb00, flags=0, str=0x55555582c022 ":.gitmodules", repo=0x555555ac1da0 <the_repo>) at object-name.c:1947 #7 repo_get_oid (r=r@entry=0x555555ac1da0 <the_repo>, name=name@entry=0x55555582c022 ":.gitmodules", oid=oid@entry=0x7fffffffdb00) at object-name.c:1603 #8 0x000055555577330f in config_from_gitmodules (fn=fn@entry=0x555555773460 <gitmodules_fetch_config>, repo=0x555555ac1da0 <the_repo>, data=data@entry=0x7fffffffdb60) at submodule-config.c:650 #9 0x000055555577462d in config_from_gitmodules (data=0x7fffffffdb60, repo=<optimized out>, fn=0x555555773460 <gitmodules_fetch_config>) at submodule-config.c:638 #10 fetch_config_from_gitmodules (max_children=<optimized out>, recurse_submodules=<optimized out>) at submodule-config.c:800 #11 0x00005555555b9e41 in cmd_fetch (argc=1, argv=0x7fffffffe090, prefix=0x0) at builtin/fetch.c:1999 #12 0x0000555555573ff6 in run_builtin (argv=<optimized out>, argc=<optimized out>, p=<optimized out>) at git.c:528 #13 handle_builtin (argc=<optimized out>, argv=<optimized out>) at git.c:785 #14 0x000055555557528c in run_argv (argv=0x7fffffffddf0, argcp=0x7fffffffddfc) at git.c:857 #15 cmd_main (argc=<optimized out>, argv=<optimized out>) at git.c:993 #16 0x0000555555573ac8 in main (argc=3, argv=0x7fffffffe088) at common-main.c:52 ``` The operations these commands use are guarded by items such as `index_name_pos()` and others. Since the `.gitmodules` file is always at root, we would not need to expand, anyway.

When fetching packfiles, we write a bunch of lockfiles for the packfiles we're writing into the repository. In order to not leave behind any cruft in case we exit or receive a signal, we register both an exit handler as well as signal handlers for common signals like SIGINT. These handlers will then unlink the locks and free the data structure tracking them. We have observed a deadlock in this logic though: (gdb) bt #0 __lll_lock_wait_private () at ../sysdeps/unix/sysv/linux/x86_64/lowlevellock.S:95 #1 0x00007f4932bea2cd in _int_free (av=0x7f4932f2eb20 <main_arena>, p=0x3e3e4200, have_lock=0) at malloc.c:3969 #2 0x00007f4932bee58c in __GI___libc_free (mem=<optimized out>) at malloc.c:2975 #3 0x0000000000662ab1 in string_list_clear () #4 0x000000000044f5bc in unlock_pack_on_signal () #5 <signal handler called> #6 _int_free (av=0x7f4932f2eb20 <main_arena>, p=<optimized out>, have_lock=0) at malloc.c:4024 #7 0x00007f4932bee58c in __GI___libc_free (mem=<optimized out>) at malloc.c:2975 #8 0x000000000065afd5 in strbuf_release () #9 0x000000000066ddb9 in delete_tempfile () #10 0x0000000000610d0b in files_transaction_cleanup.isra () #11 0x0000000000611718 in files_transaction_abort () #12 0x000000000060d2ef in ref_transaction_abort () #13 0x000000000060d441 in ref_transaction_prepare () #14 0x000000000060e0b5 in ref_transaction_commit () #15 0x00000000004511c2 in fetch_and_consume_refs () #16 0x000000000045279a in cmd_fetch () #17 0x0000000000407c48 in handle_builtin () #18 0x0000000000408df2 in cmd_main () #19 0x00000000004078b5 in main () The process was killed with a signal, which caused the signal handler to kick in and try free the data structures after we have unlinked the locks. It then deadlocks while calling free(3P). The root cause of this is that it is not allowed to call certain functions in async-signal handlers, as specified by signal-safety(7). Next to most I/O functions, this list of disallowed functions also includes memory-handling functions like malloc(3P) and free(3P) because they may not be reentrant. As a result, if we execute such functions in the signal handler, then they may operate on inconistent state and fail in unexpected ways. Fix this bug by not calling non-async-signal-safe functions when running in the signal handler. We're about to re-raise the signal anyway and will thus exit, so it's not much of a problem to keep the string list of lockfiles untouched. Note that it's fine though to call unlink(2), so we'll still clean up the lockfiles correctly. Signed-off-by: Patrick Steinhardt <ps@pks.im> Reviewed-by: brian m. carlson <sandals@crustytoothpaste.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>

When I was playing around with trace2 data and creating flamegraphs, I tried a `git fetch` call to see how the `git-remote-https` command would show up. What I didn't expect was an `ensure_full_index()` region! It turns out that `git fetch` and `git pull` need to check the index for a `.gitmodules` file to see if it should recurse into any submodules. Here is the stack trace from a debugger: ``` #0 ensure_full_index (istate=0x555555ac1c80 <the_index>) at sparse-index.c:404 #1 0x000055555571a979 in do_read_index (istate=istate@entry=0x555555ac1c80 <the_index>, path=path@entry=0x555555ad7b90 ".git/index", must_exist=must_exist@entry=0) at read-cache.c:2386 #2 0x000055555571eb7d in do_read_index (must_exist=0, path=0x555555ad7b90 ".git/index", istate=0x555555ac1c80 <the_index>) at hash.h:244 #3 read_index_from (istate=0x555555ac1c80 <the_index>, path=0x555555ad7b90 ".git/index", gitdir=0x555555ad7b30 ".git") at read-cache.c:2426 #4 0x000055555573f4c2 in repo_read_index (repo=repo@entry=0x555555ac1da0 <the_repo>) at repository.c:286 #5 0x00005555556f14d0 in get_oid_with_context_1 (repo=repo@entry=0x555555ac1da0 <the_repo>, name=name@entry=0x55555582c022 ":.gitmodules", flags=flags@entry=0, prefix=prefix@entry=0x0, oid=oid@entry=0x7fffffffdb00, oc=oc@entry=0x7fffffffda70) at object-name.c:1850 #6 0x00005555556f1f53 in get_oid_with_context (oc=0x7fffffffda70, oid=0x7fffffffdb00, flags=0, str=0x55555582c022 ":.gitmodules", repo=0x555555ac1da0 <the_repo>) at object-name.c:1947 #7 repo_get_oid (r=r@entry=0x555555ac1da0 <the_repo>, name=name@entry=0x55555582c022 ":.gitmodules", oid=oid@entry=0x7fffffffdb00) at object-name.c:1603 #8 0x000055555577330f in config_from_gitmodules (fn=fn@entry=0x555555773460 <gitmodules_fetch_config>, repo=0x555555ac1da0 <the_repo>, data=data@entry=0x7fffffffdb60) at submodule-config.c:650 #9 0x000055555577462d in config_from_gitmodules (data=0x7fffffffdb60, repo=<optimized out>, fn=0x555555773460 <gitmodules_fetch_config>) at submodule-config.c:638 #10 fetch_config_from_gitmodules (max_children=<optimized out>, recurse_submodules=<optimized out>) at submodule-config.c:800 #11 0x00005555555b9e41 in cmd_fetch (argc=1, argv=0x7fffffffe090, prefix=0x0) at builtin/fetch.c:1999 #12 0x0000555555573ff6 in run_builtin (argv=<optimized out>, argc=<optimized out>, p=<optimized out>) at git.c:528 #13 handle_builtin (argc=<optimized out>, argv=<optimized out>) at git.c:785 #14 0x000055555557528c in run_argv (argv=0x7fffffffddf0, argcp=0x7fffffffddfc) at git.c:857 #15 cmd_main (argc=<optimized out>, argv=<optimized out>) at git.c:993 #16 0x0000555555573ac8 in main (argc=3, argv=0x7fffffffe088) at common-main.c:52 ``` The operations these commands use are guarded by items such as `index_name_pos()` and others. Since the `.gitmodules` file is always at root, we would not need to expand, anyway.

When trying to write a MIDX, we already prevent the case where there weren't any packs present, and thus we would have written an empty MIDX. But there is another "empty" case, which is more interesting, and we don't yet handle. If we try to write a MIDX which has at least one pack, but those packs together don't contain any objects, we will encounter a BUG() when trying to use the bitmap corresponding to that MIDX, like so: $ git rev-parse HEAD | git pack-objects --revs --use-bitmap-index --stdout >/dev/null BUG: pack-revindex.c:394: pack_pos_to_midx: out-of-bounds object at 0 (note that in the above reproduction, both `--use-bitmap-index` and `--stdout` are important, since without the former we won't even both to load the .bitmap, and without the latter we wont attempt pack reuse). The problem occurs when we try to discover the identity of the preferred pack to determine which range if any of existing packs we can reuse verbatim. This path is: `reuse_packfile_objects()` -> `reuse_partial_packfile_from_bitmap()` -> `midx_preferred_pack()`. #4 0x000055555575401f in pack_pos_to_midx (m=0x555555997160, pos=0) at pack-revindex.c:394 #5 0x00005555557502c8 in midx_preferred_pack (bitmap_git=0x55555599c280) at pack-bitmap.c:1431 #6 0x000055555575036c in reuse_partial_packfile_from_bitmap (bitmap_git=0x55555599c280, packfile_out=0x5555559666b0 <reuse_packfile>, entries=0x5555559666b8 <reuse_packfile_objects>, reuse_out=0x5555559666c0 <reuse_packfile_bitmap>) at pack-bitmap.c:1452 #7 0x00005555556041f6 in get_object_list_from_bitmap (revs=0x7fffffffcbf0) at builtin/pack-objects.c:3658 #8 0x000055555560465c in get_object_list (ac=2, av=0x555555997050) at builtin/pack-objects.c:3765 #9 0x0000555555605e4e in cmd_pack_objects (argc=0, argv=0x7fffffffe920, prefix=0x0) at builtin/pack-objects.c:4154 Since neither the .bitmap or MIDX stores the identity of the preferred pack, we infer it by trying to load the first object in pseudo-pack order, and then asking the MIDX which pack was chosen to represent that object. But this fails our bounds check, since there are zero objects in the MIDX to begin with, which results in the BUG(). We could catch this more carefully in `midx_preferred_pack()`, but signaling the absence of a preferred pack out to all of its callers is somewhat awkward. Instead, let's avoid writing a MIDX .bitmap without any objects altogether. We catch this case in `write_midx_internal()`, and emit a warning if the caller indicated they wanted to write a bitmap before clearing out the relevant flags. If we somehow got to write_midx_bitmap(), then we will call BUG(), but this should now be an unreachable path. Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Add "fast_unwind_on_malloc=0" to LSAN_OPTIONS to get more meaningful stack traces from LSAN. This isn't required under ASAN which will emit traces such as this one for a leak in "t/t0006-date.sh": $ ASAN_OPTIONS=detect_leaks=1 ./t0006-date.sh -vixd [...] Direct leak of 3 byte(s) in 1 object(s) allocated from: #0 0x488b94 in strdup (t/helper/test-tool+0x488b94) #1 0x9444a4 in xstrdup wrapper.c:29:14 #2 0x5995fa in parse_date_format date.c:991:24 #3 0x4d2056 in show_dates t/helper/test-date.c:39:2 #4 0x4d174a in cmd__date t/helper/test-date.c:116:3 #5 0x4cce89 in cmd_main t/helper/test-tool.c:127:11 #6 0x4cd1e3 in main common-main.c:52:11 #7 0x7fef3c695e49 in __libc_start_main csu/../csu/libc-start.c:314:16 #8 0x422b09 in _start (t/helper/test-tool+0x422b09) SUMMARY: AddressSanitizer: 3 byte(s) leaked in 1 allocation(s). Aborted Whereas LSAN would emit this instead: $ ./t0006-date.sh -vixd [...] Direct leak of 3 byte(s) in 1 object(s) allocated from: #0 0x4323b8 in malloc (t/helper/test-tool+0x4323b8) #1 0x7f2be1d614aa in strdup string/strdup.c:42:15 SUMMARY: LeakSanitizer: 3 byte(s) leaked in 1 allocation(s). Aborted Now we'll instead git this sensible stack trace under LSAN. I.e. almost the same one (but starting with "malloc", as is usual for LSAN) as under ASAN: Direct leak of 3 byte(s) in 1 object(s) allocated from: #0 0x4323b8 in malloc (t/helper/test-tool+0x4323b8) #1 0x7f012af5c4aa in strdup string/strdup.c:42:15 #2 0x5cb164 in xstrdup wrapper.c:29:14 #3 0x495ee9 in parse_date_format date.c:991:24 #4 0x453aac in show_dates t/helper/test-date.c:39:2 #5 0x453782 in cmd__date t/helper/test-date.c:116:3 #6 0x451d95 in cmd_main t/helper/test-tool.c:127:11 #7 0x451f1e in main common-main.c:52:11 #8 0x7f012aef5e49 in __libc_start_main csu/../csu/libc-start.c:314:16 #9 0x42e0a9 in _start (t/helper/test-tool+0x42e0a9) SUMMARY: LeakSanitizer: 3 byte(s) leaked in 1 allocation(s). Aborted As the option name suggests this does make things slower, e.g. for t0001-init.sh we're around 10% slower: $ hyperfine -L v 0,1 'LSAN_OPTIONS=fast_unwind_on_malloc={v} make T=t0001-init.sh' -r 3 Benchmark 1: LSAN_OPTIONS=fast_unwind_on_malloc=0 make T=t0001-init.sh Time (mean ± σ): 2.135 s ± 0.015 s [User: 1.951 s, System: 0.554 s] Range (min … max): 2.122 s … 2.152 s 3 runs Benchmark 2: LSAN_OPTIONS=fast_unwind_on_malloc=1 make T=t0001-init.sh Time (mean ± σ): 1.981 s ± 0.055 s [User: 1.769 s, System: 0.488 s] Range (min … max): 1.941 s … 2.044 s 3 runs Summary 'LSAN_OPTIONS=fast_unwind_on_malloc=1 make T=t0001-init.sh' ran 1.08 ± 0.03 times faster than 'LSAN_OPTIONS=fast_unwind_on_malloc=0 make T=t0001-init.sh' I think that's more than worth it to get the more meaningful stack traces, we can always provide LSAN_OPTIONS=fast_unwind_on_malloc=0 for one-off "fast" runs. Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>

In the preceding [1] (pack-objects: move revs out of get_object_list(), 2022-03-22) the "repo_init_revisions()" was moved to cmd_pack_objects() so that it unconditionally took place for all invocations of "git pack-objects". We'd thus start leaking memory, which is easily reproduced in e.g. git.git by feeding e83c516 (Initial revision of "git", the information manager from hell, 2005-04-07) to "git pack-objects"; $ echo e83c516 | ./git pack-objects initial [...] ==19130==ERROR: LeakSanitizer: detected memory leaks Direct leak of 7120 byte(s) in 1 object(s) allocated from: #0 0x455308 in __interceptor_malloc (/home/avar/g/git/git+0x455308) #1 0x75b399 in do_xmalloc /home/avar/g/git/wrapper.c:41:8 #2 0x75b356 in xmalloc /home/avar/g/git/wrapper.c:62:9 #3 0x5d7609 in prep_parse_options /home/avar/g/git/diff.c:5647:2 #4 0x5d415a in repo_diff_setup /home/avar/g/git/diff.c:4621:2 #5 0x6dffbb in repo_init_revisions /home/avar/g/git/revision.c:1853:2 #6 0x4f599d in cmd_pack_objects /home/avar/g/git/builtin/pack-objects.c:3980:2 #7 0x4592ca in run_builtin /home/avar/g/git/git.c:465:11 #8 0x457d81 in handle_builtin /home/avar/g/git/git.c:718:3 #9 0x458ca5 in run_argv /home/avar/g/git/git.c:785:4 #10 0x457b40 in cmd_main /home/avar/g/git/git.c:916:19 #11 0x562259 in main /home/avar/g/git/common-main.c:56:11 #12 0x7fce792ac7ec in __libc_start_main csu/../csu/libc-start.c:332:16 #13 0x4300f9 in _start (/home/avar/g/git/git+0x4300f9) SUMMARY: LeakSanitizer: 7120 byte(s) leaked in 1 allocation(s). Aborted Narrowly fixing that commit would have been easy, just add call repo_init_revisions() right before get_object_list(), which is effectively what was done before that commit. But an unstated constraint when setting it up early is that it was needed for the subsequent [2] (pack-objects: parse --filter directly into revs.filter, 2022-03-22), i.e. we might have a --filter command-line option, and need to either have the "struct rev_info" setup when we encounter that option, or later. Let's just change the control flow so that we'll instead set up the "struct rev_info" only when we need it. Doing so leads to a bit more verbosity, but it's a lot clearer what we're doing and why. An earlier version of this commit[3] went behind opt_parse_list_objects_filter()'s back by faking up a "struct option" before calling it. Let's avoid that and instead create a blessed API for this pattern. We could furthermore combine the two get_object_list() invocations here by having repo_init_revisions() invoked on &pfd.revs, but I think clearly separating the two makes the flow clearer. Likewise redundantly but explicitly (i.e. redundant v.s. a "{ 0 }") "0" to "have_revs" early in cmd_pack_objects(). While we're at it add parentheses around the arguments to the OPT_* macros in in list-objects-filter-options.h, as we need to change those lines anyway. It doesn't matter in this case, but is good general practice. 1. https://lore.kernel.org/git/619b757d98465dbc4995bdc11a5282fbfcbd3daa.1647970119.git.gitgitgadget@gmail.com 2. https://lore.kernel.org/git/97de926904988b89b5663bd4c59c011a1723a8f5.1647970119.git.gitgitgadget@gmail.com 3. https://lore.kernel.org/git/patch-1.1-193534b0f07-20220325T121715Z-avarab@gmail.com/ Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Since commit fcc07e9 (is_promisor_object(): free tree buffer after parsing, 2021-04-13), we'll always free the buffers attached to a "struct tree" after searching them for promisor links. But there's an important case where we don't want to do so: if somebody else is already using the tree! This can happen during a "rev-list --missing=allow-promisor" traversal in a partial clone that is missing one or more trees or blobs. The backtrace for the free looks like this: #1 free_tree_buffer tree.c:147 #2 add_promisor_object packfile.c:2250 #3 for_each_object_in_pack packfile.c:2190 #4 for_each_packed_object packfile.c:2215 #5 is_promisor_object packfile.c:2272 #6 finish_object__ma builtin/rev-list.c:245 #7 finish_object builtin/rev-list.c:261 #8 show_object builtin/rev-list.c:274 #9 process_blob list-objects.c:63 #10 process_tree_contents list-objects.c:145 #11 process_tree list-objects.c:201 #12 traverse_trees_and_blobs list-objects.c:344 [...] We're in the middle of walking through the entries of a tree object via process_tree_contents(). We see a blob (or it could even be another tree entry) that we don't have, so we call is_promisor_object() to check it. That function loops over all of the objects in the promisor packfile, including the tree we're currently walking. When we're done with it there, we free the tree buffer. But as we return to the walk in process_tree_contents(), it's still holding on to a pointer to that buffer, via its tree_desc iterator, and it accesses the freed memory. Even a trivial use of "--missing=allow-promisor" triggers this problem, as the included test demonstrates (it's just a vanilla --blob:none clone). We can detect this case by only freeing the tree buffer if it was allocated on our behalf. This is a little tricky since that happens inside parse_object(), and it doesn't tell us whether the object was already parsed, or whether it allocated the buffer itself. But by checking for an already-parsed tree beforehand, we can distinguish the two cases. That feels a little hacky, and does incur an extra lookup in the object-hash table. But that cost is fairly minimal compared to actually loading objects (and since we're iterating the whole pack here, we're likely to be loading most objects, rather than reusing cached results). It may also be a good direction for this function in general, as there are other possible optimizations that rely on doing some analysis before parsing: - we could detect blobs and avoid reading their contents; they can't link to other objects, but parse_object() doesn't know that we don't care about checking their hashes. - we could avoid allocating object structs entirely for most objects (since we really only need them in the oidset), which would save some memory. - promisor commits could use the commit-graph rather than loading the object from disk This commit doesn't do any of those optimizations, but I think it argues that this direction is reasonable, rather than relying on parse_object() and trying to teach it to give us more information about whether it parsed. The included test fails reliably under SANITIZE=address just when running "rev-list --missing=allow-promisor". Checking the output isn't strictly necessary to detect the bug, but it seems like a reasonable addition given the general lack of coverage for "allow-promisor" in the test suite. Reported-by: Andrew Olsen <andrew.olsen@koordinates.com> Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Fix a memory leak occuring in case of pathspec copy in preload_index. Direct leak of 8 byte(s) in 8 object(s) allocated from: #0 0x7f0a353ead47 in __interceptor_malloc (/usr/lib/gcc/x86_64-pc-linux-gnu/11.3.0/libasan.so.6+0xb5d47) #1 0x55750995e840 in do_xmalloc /home/anthony/src/c/git/wrapper.c:51 #2 0x55750995e840 in xmalloc /home/anthony/src/c/git/wrapper.c:72 #3 0x55750970f824 in copy_pathspec /home/anthony/src/c/git/pathspec.c:684 #4 0x557509717278 in preload_index /home/anthony/src/c/git/preload-index.c:135 #5 0x55750975f21e in refresh_index /home/anthony/src/c/git/read-cache.c:1633 #6 0x55750915b926 in cmd_status builtin/commit.c:1547 #7 0x5575090e1680 in run_builtin /home/anthony/src/c/git/git.c:466 #8 0x5575090e1680 in handle_builtin /home/anthony/src/c/git/git.c:720 #9 0x5575090e284a in run_argv /home/anthony/src/c/git/git.c:787 #10 0x5575090e284a in cmd_main /home/anthony/src/c/git/git.c:920 #11 0x5575090dbf82 in main /home/anthony/src/c/git/common-main.c:56 #12 0x7f0a348230ab (/lib64/libc.so.6+0x290ab) Signed-off-by: Anthony Delannoy <anthony.2lannoy@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>

In the tmp-objdir api, tmp_objdir_create will create a temporary directory but also register signal handlers responsible for removing the directory's contents and the directory itself. However, the function responsible for recursively removing the contents and directory, remove_dir_recurse() calls opendir(3) and closedir(3). This can be problematic because these functions allocate and free memory, which are not async-signal-safe functions. This can lead to deadlocks. One place we call tmp_objdir_create() is in git-receive-pack, where we create a temporary quarantine directory "incoming". Incoming objects will be written to this directory before they get moved to the object directory. We have observed this code leading to a deadlock: Thread 1 (Thread 0x7f621ba0b200 (LWP 326305)): #0 __lll_lock_wait_private (futex=futex@entry=0x7f621bbf8b80 <main_arena>) at ./lowlevellock.c:35 #1 0x00007f621baa635b in __GI___libc_malloc (bytes=bytes@entry=32816) at malloc.c:3064 #2 0x00007f621bae9f49 in __alloc_dir (statp=0x7fff2ea7ed60, flags=0, close_fd=true, fd=5) at ../sysdeps/posix/opendir.c:118 #3 opendir_tail (fd=5) at ../sysdeps/posix/opendir.c:69 #4 __opendir (name=<optimized out>) at ../sysdeps/posix/opendir.c:92 #5 0x0000557c19c77de1 in remove_dir_recurse () git#6 0x0000557c19d81a4f in remove_tmp_objdir_on_signal () #7 <signal handler called> git#8 _int_malloc (av=av@entry=0x7f621bbf8b80 <main_arena>, bytes=bytes@entry=7160) at malloc.c:4116 git#9 0x00007f621baa62c9 in __GI___libc_malloc (bytes=7160) at malloc.c:3066 git#10 0x00007f621bd1e987 in inflateInit2_ () from /opt/gitlab/embedded/lib/libz.so.1 git#11 0x0000557c19dbe5f4 in git_inflate_init () git#12 0x0000557c19cee02a in unpack_compressed_entry () git#13 0x0000557c19cf08cb in unpack_entry () git#14 0x0000557c19cf0f32 in packed_object_info () git#15 0x0000557c19cd68cd in do_oid_object_info_extended () git#16 0x0000557c19cd6e2b in read_object_file_extended () git#17 0x0000557c19cdec2f in parse_object () git#18 0x0000557c19c34977 in lookup_commit_reference_gently () git#19 0x0000557c19d69309 in mark_uninteresting () git#20 0x0000557c19d2d180 in do_for_each_repo_ref_iterator () git#21 0x0000557c19d21678 in for_each_ref () git#22 0x0000557c19d6a94f in assign_shallow_commits_to_refs () git#23 0x0000557c19bc02b2 in cmd_receive_pack () git#24 0x0000557c19b29fdd in handle_builtin () git#25 0x0000557c19b2a526 in cmd_main () git#26 0x0000557c19b28ea2 in main () Since we can't do the cleanup in a portable and signal-safe way, skip the cleanup when we're handling a signal. This means that when signal handling, the temporary directory may not get cleaned up properly. This is mitigated by b3cecf4 (tmp-objdir: new API for creating temporary writable databases, 2021-12-06) which changed the default name and allows gc to clean up these temporary directories. In the event of a normal exit, we should still be cleaning up via the atexit() handler. Helped-by: Jeff King <peff@peff.net> Signed-off-by: John Cai <johncai86@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>

There is an out-of-bounds read possible when parsing gitattributes that have an attribute that is 2^31+1 bytes long. This is caused due to an integer overflow when we assign the result of strlen(3P) to an `int`, where we use the wrapped-around value in a subsequent call to memcpy(3P). The following code reproduces the issue: blob=$(perl -e 'print "a" x 2147483649 . " attr"' | git hash-object -w --stdin) git update-index --add --cacheinfo 100644,$blob,.gitattributes git check-attr --all file AddressSanitizer:DEADLYSIGNAL ================================================================= ==8451==ERROR: AddressSanitizer: SEGV on unknown address 0x7f93efa00800 (pc 0x7f94f1f8f082 bp 0x7ffddb59b3a0 sp 0x7ffddb59ab28 T0) ==8451==The signal is caused by a READ memory access. #0 0x7f94f1f8f082 (/usr/lib/libc.so.6+0x176082) #1 0x7f94f2047d9c in __interceptor_strspn /usr/src/debug/gcc/libsanitizer/sanitizer_common/sanitizer_common_interceptors.inc:752 #2 0x560e190f7f26 in parse_attr_line attr.c:375 #3 0x560e190f9663 in handle_attr_line attr.c:660 #4 0x560e190f9ddd in read_attr_from_index attr.c:769 #5 0x560e190f9f14 in read_attr attr.c:797 #6 0x560e190fa24e in bootstrap_attr_stack attr.c:867 #7 0x560e190fa4a5 in prepare_attr_stack attr.c:902 #8 0x560e190fb5dc in collect_some_attrs attr.c:1097 #9 0x560e190fb93f in git_all_attrs attr.c:1128 #10 0x560e18e6136e in check_attr builtin/check-attr.c:67 #11 0x560e18e61c12 in cmd_check_attr builtin/check-attr.c:183 #12 0x560e18e15993 in run_builtin git.c:466 #13 0x560e18e16397 in handle_builtin git.c:721 #14 0x560e18e16b2b in run_argv git.c:788 #15 0x560e18e17991 in cmd_main git.c:926 #16 0x560e190ae2bd in main common-main.c:57 #17 0x7f94f1e3c28f (/usr/lib/libc.so.6+0x2328f) #18 0x7f94f1e3c349 in __libc_start_main (/usr/lib/libc.so.6+0x23349) #19 0x560e18e110e4 in _start ../sysdeps/x86_64/start.S:115 AddressSanitizer can not provide additional info. SUMMARY: AddressSanitizer: SEGV (/usr/lib/libc.so.6+0x176082) ==8451==ABORTING Fix this bug by converting the variable to a `size_t` instead. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>

It is possible to trigger an integer overflow when parsing attribute names when there are more than 2^31 of them for a single pattern. This can either lead to us dying due to trying to request too many bytes: blob=$(perl -e 'print "f" . " a=" x 2147483649' | git hash-object -w --stdin) git update-index --add --cacheinfo 100644,$blob,.gitattributes git attr-check --all file ================================================================= ==1022==ERROR: AddressSanitizer: requested allocation size 0xfffffff800000032 (0xfffffff800001038 after adjustments for alignment, red zones etc.) exceeds maximum supported size of 0x10000000000 (thread T0) #0 0x7fd3efabf411 in __interceptor_calloc /usr/src/debug/gcc/libsanitizer/asan/asan_malloc_linux.cpp:77 #1 0x5563a0a1e3d3 in xcalloc wrapper.c:150 #2 0x5563a058d005 in parse_attr_line attr.c:384 #3 0x5563a058e661 in handle_attr_line attr.c:660 #4 0x5563a058eddb in read_attr_from_index attr.c:769 #5 0x5563a058ef12 in read_attr attr.c:797 #6 0x5563a058f24c in bootstrap_attr_stack attr.c:867 #7 0x5563a058f4a3 in prepare_attr_stack attr.c:902 #8 0x5563a05905da in collect_some_attrs attr.c:1097 #9 0x5563a059093d in git_all_attrs attr.c:1128 #10 0x5563a02f636e in check_attr builtin/check-attr.c:67 #11 0x5563a02f6c12 in cmd_check_attr builtin/check-attr.c:183 #12 0x5563a02aa993 in run_builtin git.c:466 #13 0x5563a02ab397 in handle_builtin git.c:721 #14 0x5563a02abb2b in run_argv git.c:788 #15 0x5563a02ac991 in cmd_main git.c:926 #16 0x5563a05432bd in main common-main.c:57 #17 0x7fd3ef82228f (/usr/lib/libc.so.6+0x2328f) ==1022==HINT: if you don't care about these errors you may set allocator_may_return_null=1 SUMMARY: AddressSanitizer: allocation-size-too-big /usr/src/debug/gcc/libsanitizer/asan/asan_malloc_linux.cpp:77 in __interceptor_calloc ==1022==ABORTING Or, much worse, it can lead to an out-of-bounds write because we underallocate and then memcpy(3P) into an array: perl -e ' print "A " . "\rh="x2000000000; print "\rh="x2000000000; print "\rh="x294967294 . "\n" ' >.gitattributes git add .gitattributes git commit -am "evil attributes" $ git clone --quiet /path/to/repo ================================================================= ==15062==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x602000002550 at pc 0x5555559884d5 bp 0x7fffffffbc60 sp 0x7fffffffbc58 WRITE of size 8 at 0x602000002550 thread T0 #0 0x5555559884d4 in parse_attr_line attr.c:393 #1 0x5555559884d4 in handle_attr_line attr.c:660 #2 0x555555988902 in read_attr_from_index attr.c:784 #3 0x555555988902 in read_attr_from_index attr.c:747 #4 0x555555988a1d in read_attr attr.c:800 #5 0x555555989b0c in bootstrap_attr_stack attr.c:882 #6 0x555555989b0c in prepare_attr_stack attr.c:917 #7 0x555555989b0c in collect_some_attrs attr.c:1112 #8 0x55555598b141 in git_check_attr attr.c:1126 #9 0x555555a13004 in convert_attrs convert.c:1311 #10 0x555555a95e04 in checkout_entry_ca entry.c:553 #11 0x555555d58bf6 in checkout_entry entry.h:42 #12 0x555555d58bf6 in check_updates unpack-trees.c:480 #13 0x555555d5eb55 in unpack_trees unpack-trees.c:2040 #14 0x555555785ab7 in checkout builtin/clone.c:724 #15 0x555555785ab7 in cmd_clone builtin/clone.c:1384 #16 0x55555572443c in run_builtin git.c:466 #17 0x55555572443c in handle_builtin git.c:721 #18 0x555555727872 in run_argv git.c:788 #19 0x555555727872 in cmd_main git.c:926 #20 0x555555721fa0 in main common-main.c:57 #21 0x7ffff73f1d09 in __libc_start_main ../csu/libc-start.c:308 #22 0x555555723f39 in _start (git+0x1cff39) 0x602000002552 is located 0 bytes to the right of 2-byte region [0x602000002550,0x602000002552) allocated by thread T0 here: #0 0x7ffff768c037 in __interceptor_calloc ../../../../src/libsanitizer/asan/asan_malloc_linux.cpp:154 #1 0x555555d7fff7 in xcalloc wrapper.c:150 #2 0x55555598815f in parse_attr_line attr.c:384 #3 0x55555598815f in handle_attr_line attr.c:660 #4 0x555555988902 in read_attr_from_index attr.c:784 #5 0x555555988902 in read_attr_from_index attr.c:747 #6 0x555555988a1d in read_attr attr.c:800 #7 0x555555989b0c in bootstrap_attr_stack attr.c:882 #8 0x555555989b0c in prepare_attr_stack attr.c:917 #9 0x555555989b0c in collect_some_attrs attr.c:1112 #10 0x55555598b141 in git_check_attr attr.c:1126 #11 0x555555a13004 in convert_attrs convert.c:1311 #12 0x555555a95e04 in checkout_entry_ca entry.c:553 #13 0x555555d58bf6 in checkout_entry entry.h:42 #14 0x555555d58bf6 in check_updates unpack-trees.c:480 #15 0x555555d5eb55 in unpack_trees unpack-trees.c:2040 #16 0x555555785ab7 in checkout builtin/clone.c:724 #17 0x555555785ab7 in cmd_clone builtin/clone.c:1384 #18 0x55555572443c in run_builtin git.c:466 #19 0x55555572443c in handle_builtin git.c:721 #20 0x555555727872 in run_argv git.c:788 #21 0x555555727872 in cmd_main git.c:926 #22 0x555555721fa0 in main common-main.c:57 #23 0x7ffff73f1d09 in __libc_start_main ../csu/libc-start.c:308 SUMMARY: AddressSanitizer: heap-buffer-overflow attr.c:393 in parse_attr_line Shadow bytes around the buggy address: 0x0c047fff8450: fa fa 00 02 fa fa 00 07 fa fa fd fd fa fa 00 00 0x0c047fff8460: fa fa 02 fa fa fa fd fd fa fa 00 06 fa fa 05 fa 0x0c047fff8470: fa fa fd fd fa fa 00 02 fa fa 06 fa fa fa 05 fa 0x0c047fff8480: fa fa 07 fa fa fa fd fd fa fa 00 01 fa fa 00 02 0x0c047fff8490: fa fa 00 03 fa fa 00 fa fa fa 00 01 fa fa 00 03 =>0x0c047fff84a0: fa fa 00 01 fa fa 00 02 fa fa[02]fa fa fa fa fa 0x0c047fff84b0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa 0x0c047fff84c0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa 0x0c047fff84d0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa 0x0c047fff84e0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa 0x0c047fff84f0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa Shadow byte legend (one shadow byte represents 8 application bytes): Addressable: 00 Partially addressable: 01 02 03 04 05 06 07 Heap left redzone: fa Freed heap region: fd Stack left redzone: f1 Stack mid redzone: f2 Stack right redzone: f3 Stack after return: f5 Stack use after scope: f8 Global redzone: f9 Global init order: f6 Poisoned by user: f7 Container overflow: fc Array cookie: ac Intra object redzone: bb ASan internal: fe Left alloca redzone: ca Right alloca redzone: cb Shadow gap: cc ==15062==ABORTING Fix this bug by using `size_t` instead to count the number of attributes so that this value cannot reasonably overflow without running out of memory before already. Reported-by: Markus Vervier <markus.vervier@x41-dsec.de> Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>

When using a padding specifier in the pretty format passed to git-log(1) we need to calculate the string length in several places. These string lengths are stored in `int`s though, which means that these can easily overflow when the input lengths exceeds 2GB. This can ultimately lead to an out-of-bounds write when these are used in a call to memcpy(3P): ==8340==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x7f1ec62f97fe at pc 0x7f2127e5f427 bp 0x7ffd3bd63de0 sp 0x7ffd3bd63588 WRITE of size 1 at 0x7f1ec62f97fe thread T0 #0 0x7f2127e5f426 in __interceptor_memcpy /usr/src/debug/gcc/libsanitizer/sanitizer_common/sanitizer_common_interceptors.inc:827 #1 0x5628e96aa605 in format_and_pad_commit pretty.c:1762 #2 0x5628e96aa7f4 in format_commit_item pretty.c:1801 #3 0x5628e97cdb24 in strbuf_expand strbuf.c:429 #4 0x5628e96ab060 in repo_format_commit_message pretty.c:1869 #5 0x5628e96acd0f in pretty_print_commit pretty.c:2161 #6 0x5628e95a44c8 in show_log log-tree.c:781 #7 0x5628e95a76ba in log_tree_commit log-tree.c:1117 #8 0x5628e922bed5 in cmd_log_walk_no_free builtin/log.c:508 #9 0x5628e922c35b in cmd_log_walk builtin/log.c:549 #10 0x5628e922f1a2 in cmd_log builtin/log.c:883 #11 0x5628e9106993 in run_builtin git.c:466 #12 0x5628e9107397 in handle_builtin git.c:721 #13 0x5628e9107b07 in run_argv git.c:788 #14 0x5628e91088a7 in cmd_main git.c:923 #15 0x5628e939d682 in main common-main.c:57 #16 0x7f2127c3c28f (/usr/lib/libc.so.6+0x2328f) #17 0x7f2127c3c349 in __libc_start_main (/usr/lib/libc.so.6+0x23349) #18 0x5628e91020e4 in _start ../sysdeps/x86_64/start.S:115 0x7f1ec62f97fe is located 2 bytes to the left of 4831838265-byte region [0x7f1ec62f9800,0x7f1fe62f9839) allocated by thread T0 here: #0 0x7f2127ebe7ea in __interceptor_realloc /usr/src/debug/gcc/libsanitizer/asan/asan_malloc_linux.cpp:85 #1 0x5628e98774d4 in xrealloc wrapper.c:136 #2 0x5628e97cb01c in strbuf_grow strbuf.c:99 #3 0x5628e97ccd42 in strbuf_addchars strbuf.c:327 #4 0x5628e96aa55c in format_and_pad_commit pretty.c:1761 #5 0x5628e96aa7f4 in format_commit_item pretty.c:1801 #6 0x5628e97cdb24 in strbuf_expand strbuf.c:429 #7 0x5628e96ab060 in repo_format_commit_message pretty.c:1869 #8 0x5628e96acd0f in pretty_print_commit pretty.c:2161 #9 0x5628e95a44c8 in show_log log-tree.c:781 #10 0x5628e95a76ba in log_tree_commit log-tree.c:1117 #11 0x5628e922bed5 in cmd_log_walk_no_free builtin/log.c:508 #12 0x5628e922c35b in cmd_log_walk builtin/log.c:549 #13 0x5628e922f1a2 in cmd_log builtin/log.c:883 #14 0x5628e9106993 in run_builtin git.c:466 #15 0x5628e9107397 in handle_builtin git.c:721 #16 0x5628e9107b07 in run_argv git.c:788 #17 0x5628e91088a7 in cmd_main git.c:923 #18 0x5628e939d682 in main common-main.c:57 #19 0x7f2127c3c28f (/usr/lib/libc.so.6+0x2328f) #20 0x7f2127c3c349 in __libc_start_main (/usr/lib/libc.so.6+0x23349) #21 0x5628e91020e4 in _start ../sysdeps/x86_64/start.S:115 SUMMARY: AddressSanitizer: heap-buffer-overflow /usr/src/debug/gcc/libsanitizer/sanitizer_common/sanitizer_common_interceptors.inc:827 in __interceptor_memcpy Shadow bytes around the buggy address: 0x0fe458c572a0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa 0x0fe458c572b0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa 0x0fe458c572c0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa 0x0fe458c572d0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa 0x0fe458c572e0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa =>0x0fe458c572f0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa[fa] 0x0fe458c57300: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0x0fe458c57310: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0x0fe458c57320: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0x0fe458c57330: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0x0fe458c57340: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 Shadow byte legend (one shadow byte represents 8 application bytes): Addressable: 00 Partially addressable: 01 02 03 04 05 06 07 Heap left redzone: fa Freed heap region: fd Stack left redzone: f1 Stack mid redzone: f2 Stack right redzone: f3 Stack after return: f5 Stack use after scope: f8 Global redzone: f9 Global init order: f6 Poisoned by user: f7 Container overflow: fc Array cookie: ac Intra object redzone: bb ASan internal: fe Left alloca redzone: ca Right alloca redzone: cb ==8340==ABORTING The pretty format can also be used in `git archive` operations via the `export-subst` attribute. So this is what in our opinion makes this a critical issue in the context of Git forges which allow to download an archive of user supplied Git repositories. Fix this vulnerability by using `size_t` instead of `int` to track the string lengths. Add tests which detect this vulnerability when Git is compiled with the address sanitizer. Reported-by: Joern Schneeweisz <jschneeweisz@gitlab.com> Original-patch-by: Joern Schneeweisz <jschneeweisz@gitlab.com> Modified-by: Taylor Blau <me@ttalorr.com> Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>

With the `%>>(<N>)` pretty formatter, you can ask git-log(1) et al to steal spaces. To do so we need to look ahead of the next token to see whether there are spaces there. This loop takes into account ANSI sequences that end with an `m`, and if it finds any it will skip them until it finds the first space. While doing so it does not take into account the buffer's limits though and easily does an out-of-bounds read. Add a test that hits this behaviour. While we don't have an easy way to verify this, the test causes the following failure when run with `SANITIZE=address`: ==37941==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x603000000baf at pc 0x55ba6f88e0d0 bp 0x7ffc84c50d20 sp 0x7ffc84c50d10 READ of size 1 at 0x603000000baf thread T0 #0 0x55ba6f88e0cf in format_and_pad_commit pretty.c:1712 #1 0x55ba6f88e7b4 in format_commit_item pretty.c:1801 #2 0x55ba6f9b1ae4 in strbuf_expand strbuf.c:429 #3 0x55ba6f88f020 in repo_format_commit_message pretty.c:1869 #4 0x55ba6f890ccf in pretty_print_commit pretty.c:2161 #5 0x55ba6f7884c8 in show_log log-tree.c:781 #6 0x55ba6f78b6ba in log_tree_commit log-tree.c:1117 #7 0x55ba6f40fed5 in cmd_log_walk_no_free builtin/log.c:508 #8 0x55ba6f41035b in cmd_log_walk builtin/log.c:549 #9 0x55ba6f4131a2 in cmd_log builtin/log.c:883 #10 0x55ba6f2ea993 in run_builtin git.c:466 #11 0x55ba6f2eb397 in handle_builtin git.c:721 #12 0x55ba6f2ebb07 in run_argv git.c:788 #13 0x55ba6f2ec8a7 in cmd_main git.c:923 #14 0x55ba6f581682 in main common-main.c:57 #15 0x7f2d08c3c28f (/usr/lib/libc.so.6+0x2328f) #16 0x7f2d08c3c349 in __libc_start_main (/usr/lib/libc.so.6+0x23349) #17 0x55ba6f2e60e4 in _start ../sysdeps/x86_64/start.S:115 0x603000000baf is located 1 bytes to the left of 24-byte region [0x603000000bb0,0x603000000bc8) allocated by thread T0 here: #0 0x7f2d08ebe7ea in __interceptor_realloc /usr/src/debug/gcc/libsanitizer/asan/asan_malloc_linux.cpp:85 #1 0x55ba6fa5b494 in xrealloc wrapper.c:136 #2 0x55ba6f9aefdc in strbuf_grow strbuf.c:99 #3 0x55ba6f9b0a06 in strbuf_add strbuf.c:298 #4 0x55ba6f9b1a25 in strbuf_expand strbuf.c:418 #5 0x55ba6f88f020 in repo_format_commit_message pretty.c:1869 #6 0x55ba6f890ccf in pretty_print_commit pretty.c:2161 #7 0x55ba6f7884c8 in show_log log-tree.c:781 #8 0x55ba6f78b6ba in log_tree_commit log-tree.c:1117 #9 0x55ba6f40fed5 in cmd_log_walk_no_free builtin/log.c:508 #10 0x55ba6f41035b in cmd_log_walk builtin/log.c:549 #11 0x55ba6f4131a2 in cmd_log builtin/log.c:883 #12 0x55ba6f2ea993 in run_builtin git.c:466 #13 0x55ba6f2eb397 in handle_builtin git.c:721 #14 0x55ba6f2ebb07 in run_argv git.c:788 #15 0x55ba6f2ec8a7 in cmd_main git.c:923 #16 0x55ba6f581682 in main common-main.c:57 #17 0x7f2d08c3c28f (/usr/lib/libc.so.6+0x2328f) #18 0x7f2d08c3c349 in __libc_start_main (/usr/lib/libc.so.6+0x23349) #19 0x55ba6f2e60e4 in _start ../sysdeps/x86_64/start.S:115 SUMMARY: AddressSanitizer: heap-buffer-overflow pretty.c:1712 in format_and_pad_commit Shadow bytes around the buggy address: 0x0c067fff8120: fa fa fd fd fd fa fa fa fd fd fd fa fa fa fd fd 0x0c067fff8130: fd fd fa fa fd fd fd fd fa fa fd fd fd fa fa fa 0x0c067fff8140: fd fd fd fa fa fa fd fd fd fa fa fa fd fd fd fa 0x0c067fff8150: fa fa fd fd fd fd fa fa 00 00 00 fa fa fa fd fd 0x0c067fff8160: fd fa fa fa fd fd fd fa fa fa fd fd fd fa fa fa =>0x0c067fff8170: fd fd fd fa fa[fa]00 00 00 fa fa fa 00 00 00 fa 0x0c067fff8180: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa 0x0c067fff8190: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa 0x0c067fff81a0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa 0x0c067fff81b0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa 0x0c067fff81c0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa Shadow byte legend (one shadow byte represents 8 application bytes): Addressable: 00 Partially addressable: 01 02 03 04 05 06 07 Heap left redzone: fa Freed heap region: fd Stack left redzone: f1 Stack mid redzone: f2 Stack right redzone: f3 Stack after return: f5 Stack use after scope: f8 Global redzone: f9 Global init order: f6 Poisoned by user: f7 Container overflow: fc Array cookie: ac Intra object redzone: bb ASan internal: fe Left alloca redzone: ca Right alloca redzone: cb Luckily enough, this would only cause us to copy the out-of-bounds data into the formatted commit in case we really had an ANSI sequence preceding our buffer. So this bug likely has no security consequences. Fix it regardless by not traversing past the buffer's start. Reported-by: Patrick Steinhardt <ps@pks.im> Reported-by: Eric Sesterhenn <eric.sesterhenn@x41-dsec.de> Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>

An out-of-bounds read can be triggered when parsing an incomplete padding format string passed via `--pretty=format` or in Git archives when files are marked with the `export-subst` gitattribute. This bug exists since we have introduced support for truncating output via the `trunc` keyword a7f01c6 (pretty: support truncating in %>, %< and %><, 2013-04-19). Before this commit, we used to find the end of the formatting string by using strchr(3P). This function returns a `NULL` pointer in case the character in question wasn't found. The subsequent check whether any character was found thus simply checked the returned pointer. After the commit we switched to strcspn(3P) though, which only returns the offset to the first found character or to the trailing NUL byte. As the end pointer is now computed by adding the offset to the start pointer it won't be `NULL` anymore, and as a consequence the check doesn't do anything anymore. The out-of-bounds data that is being read can in fact end up in the formatted string. As a consequence, it is possible to leak memory contents either by calling git-log(1) or via git-archive(1) when any of the archived files is marked with the `export-subst` gitattribute. ==10888==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x602000000398 at pc 0x7f0356047cb2 bp 0x7fff3ffb95d0 sp 0x7fff3ffb8d78 READ of size 1 at 0x602000000398 thread T0 #0 0x7f0356047cb1 in __interceptor_strchrnul /usr/src/debug/gcc/libsanitizer/sanitizer_common/sanitizer_common_interceptors.inc:725 #1 0x563b7cec9a43 in strbuf_expand strbuf.c:417 #2 0x563b7cda7060 in repo_format_commit_message pretty.c:1869 #3 0x563b7cda8d0f in pretty_print_commit pretty.c:2161 #4 0x563b7cca04c8 in show_log log-tree.c:781 #5 0x563b7cca36ba in log_tree_commit log-tree.c:1117 #6 0x563b7c927ed5 in cmd_log_walk_no_free builtin/log.c:508 #7 0x563b7c92835b in cmd_log_walk builtin/log.c:549 #8 0x563b7c92b1a2 in cmd_log builtin/log.c:883 #9 0x563b7c802993 in run_builtin git.c:466 #10 0x563b7c803397 in handle_builtin git.c:721 #11 0x563b7c803b07 in run_argv git.c:788 #12 0x563b7c8048a7 in cmd_main git.c:923 #13 0x563b7ca99682 in main common-main.c:57 #14 0x7f0355e3c28f (/usr/lib/libc.so.6+0x2328f) #15 0x7f0355e3c349 in __libc_start_main (/usr/lib/libc.so.6+0x23349) #16 0x563b7c7fe0e4 in _start ../sysdeps/x86_64/start.S:115 0x602000000398 is located 0 bytes to the right of 8-byte region [0x602000000390,0x602000000398) allocated by thread T0 here: #0 0x7f0356072faa in __interceptor_strdup /usr/src/debug/gcc/libsanitizer/asan/asan_interceptors.cpp:439 #1 0x563b7cf7317c in xstrdup wrapper.c:39 #2 0x563b7cd9a06a in save_user_format pretty.c:40 #3 0x563b7cd9b3e5 in get_commit_format pretty.c:173 #4 0x563b7ce54ea0 in handle_revision_opt revision.c:2456 #5 0x563b7ce597c9 in setup_revisions revision.c:2850 #6 0x563b7c9269e0 in cmd_log_init_finish builtin/log.c:269 #7 0x563b7c927362 in cmd_log_init builtin/log.c:348 #8 0x563b7c92b193 in cmd_log builtin/log.c:882 #9 0x563b7c802993 in run_builtin git.c:466 #10 0x563b7c803397 in handle_builtin git.c:721 #11 0x563b7c803b07 in run_argv git.c:788 #12 0x563b7c8048a7 in cmd_main git.c:923 #13 0x563b7ca99682 in main common-main.c:57 #14 0x7f0355e3c28f (/usr/lib/libc.so.6+0x2328f) #15 0x7f0355e3c349 in __libc_start_main (/usr/lib/libc.so.6+0x23349) #16 0x563b7c7fe0e4 in _start ../sysdeps/x86_64/start.S:115 SUMMARY: AddressSanitizer: heap-buffer-overflow /usr/src/debug/gcc/libsanitizer/sanitizer_common/sanitizer_common_interceptors.inc:725 in __interceptor_strchrnul Shadow bytes around the buggy address: 0x0c047fff8020: fa fa fd fd fa fa 00 06 fa fa 05 fa fa fa fd fd 0x0c047fff8030: fa fa 00 02 fa fa 06 fa fa fa 05 fa fa fa fd fd 0x0c047fff8040: fa fa 00 07 fa fa 03 fa fa fa fd fd fa fa 00 00 0x0c047fff8050: fa fa 00 01 fa fa fd fd fa fa 00 00 fa fa 00 01 0x0c047fff8060: fa fa 00 06 fa fa 00 06 fa fa 05 fa fa fa 05 fa =>0x0c047fff8070: fa fa 00[fa]fa fa fd fa fa fa fd fd fa fa fd fd 0x0c047fff8080: fa fa fd fd fa fa 00 00 fa fa 00 fa fa fa fd fa 0x0c047fff8090: fa fa fd fd fa fa 00 00 fa fa fa fa fa fa fa fa 0x0c047fff80a0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa 0x0c047fff80b0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa 0x0c047fff80c0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa Shadow byte legend (one shadow byte represents 8 application bytes): Addressable: 00 Partially addressable: 01 02 03 04 05 06 07 Heap left redzone: fa Freed heap region: fd Stack left redzone: f1 Stack mid redzone: f2 Stack right redzone: f3 Stack after return: f5 Stack use after scope: f8 Global redzone: f9 Global init order: f6 Poisoned by user: f7 Container overflow: fc Array cookie: ac Intra object redzone: bb ASan internal: fe Left alloca redzone: ca Right alloca redzone: cb ==10888==ABORTING Fix this bug by checking whether `end` points at the trailing NUL byte. Add a test which catches this out-of-bounds read and which demonstrates that we used to write out-of-bounds data into the formatted message. Reported-by: Markus Vervier <markus.vervier@x41-dsec.de> Original-patch-by: Markus Vervier <markus.vervier@x41-dsec.de> Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>

The return type of both `utf8_strwidth()` and `utf8_strnwidth()` is `int`, but we operate on string lengths which are typically of type `size_t`. This means that when the string is longer than `INT_MAX`, we will overflow and thus return a negative result. This can lead to an out-of-bounds write with `--pretty=format:%<1)%B` and a commit message that is 2^31+1 bytes long: ================================================================= ==26009==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x603000001168 at pc 0x7f95c4e5f427 bp 0x7ffd8541c900 sp 0x7ffd8541c0a8 WRITE of size 2147483649 at 0x603000001168 thread T0 #0 0x7f95c4e5f426 in __interceptor_memcpy /usr/src/debug/gcc/libsanitizer/sanitizer_common/sanitizer_common_interceptors.inc:827 #1 0x5612bbb1068c in format_and_pad_commit pretty.c:1763 #2 0x5612bbb1087a in format_commit_item pretty.c:1801 #3 0x5612bbc33bab in strbuf_expand strbuf.c:429 #4 0x5612bbb110e7 in repo_format_commit_message pretty.c:1869 #5 0x5612bbb12d96 in pretty_print_commit pretty.c:2161 #6 0x5612bba0a4d5 in show_log log-tree.c:781 #7 0x5612bba0d6c7 in log_tree_commit log-tree.c:1117 #8 0x5612bb691ed5 in cmd_log_walk_no_free builtin/log.c:508 #9 0x5612bb69235b in cmd_log_walk builtin/log.c:549 #10 0x5612bb6951a2 in cmd_log builtin/log.c:883 #11 0x5612bb56c993 in run_builtin git.c:466 #12 0x5612bb56d397 in handle_builtin git.c:721 #13 0x5612bb56db07 in run_argv git.c:788 #14 0x5612bb56e8a7 in cmd_main git.c:923 #15 0x5612bb803682 in main common-main.c:57 #16 0x7f95c4c3c28f (/usr/lib/libc.so.6+0x2328f) #17 0x7f95c4c3c349 in __libc_start_main (/usr/lib/libc.so.6+0x23349) #18 0x5612bb5680e4 in _start ../sysdeps/x86_64/start.S:115 0x603000001168 is located 0 bytes to the right of 24-byte region [0x603000001150,0x603000001168) allocated by thread T0 here: #0 0x7f95c4ebe7ea in __interceptor_realloc /usr/src/debug/gcc/libsanitizer/asan/asan_malloc_linux.cpp:85 #1 0x5612bbcdd556 in xrealloc wrapper.c:136 #2 0x5612bbc310a3 in strbuf_grow strbuf.c:99 #3 0x5612bbc32acd in strbuf_add strbuf.c:298 #4 0x5612bbc33aec in strbuf_expand strbuf.c:418 #5 0x5612bbb110e7 in repo_format_commit_message pretty.c:1869 #6 0x5612bbb12d96 in pretty_print_commit pretty.c:2161 #7 0x5612bba0a4d5 in show_log log-tree.c:781 #8 0x5612bba0d6c7 in log_tree_commit log-tree.c:1117 #9 0x5612bb691ed5 in cmd_log_walk_no_free builtin/log.c:508 #10 0x5612bb69235b in cmd_log_walk builtin/log.c:549 #11 0x5612bb6951a2 in cmd_log builtin/log.c:883 #12 0x5612bb56c993 in run_builtin git.c:466 #13 0x5612bb56d397 in handle_builtin git.c:721 #14 0x5612bb56db07 in run_argv git.c:788 #15 0x5612bb56e8a7 in cmd_main git.c:923 #16 0x5612bb803682 in main common-main.c:57 #17 0x7f95c4c3c28f (/usr/lib/libc.so.6+0x2328f) SUMMARY: AddressSanitizer: heap-buffer-overflow /usr/src/debug/gcc/libsanitizer/sanitizer_common/sanitizer_common_interceptors.inc:827 in __interceptor_memcpy Shadow bytes around the buggy address: 0x0c067fff81d0: fd fd fd fa fa fa fd fd fd fa fa fa fd fd fd fa 0x0c067fff81e0: fa fa fd fd fd fd fa fa fd fd fd fd fa fa fd fd 0x0c067fff81f0: fd fa fa fa fd fd fd fa fa fa fd fd fd fa fa fa 0x0c067fff8200: fd fd fd fa fa fa fd fd fd fd fa fa 00 00 00 fa 0x0c067fff8210: fa fa fd fd fd fa fa fa fd fd fd fa fa fa fd fd =>0x0c067fff8220: fd fa fa fa fd fd fd fa fa fa 00 00 00[fa]fa fa 0x0c067fff8230: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa 0x0c067fff8240: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa 0x0c067fff8250: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa 0x0c067fff8260: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa 0x0c067fff8270: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa Shadow byte legend (one shadow byte represents 8 application bytes): Addressable: 00 Partially addressable: 01 02 03 04 05 06 07 Heap left redzone: fa Freed heap region: fd Stack left redzone: f1 Stack mid redzone: f2 Stack right redzone: f3 Stack after return: f5 Stack use after scope: f8 Global redzone: f9 Global init order: f6 Poisoned by user: f7 Container overflow: fc Array cookie: ac Intra object redzone: bb ASan internal: fe Left alloca redzone: ca Right alloca redzone: cb ==26009==ABORTING Now the proper fix for this would be to convert both functions to return an `size_t` instead of an `int`. But given that this commit may be part of a security release, let's instead do the minimal viable fix and die in case we see an overflow. Add a test that would have previously caused us to crash. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>

When "read_strategy_opts()" is called we may have populated the "opts->strategy" before, so we'll need to free() it to avoid leaking memory. We populate it before because we cal get_replay_opts() from within "rebase.c" with an already populated "opts", which we then copy. Then if we're doing a "rebase -i" the sequencer API itself will promptly clobber our alloc'd version of it with its own. If this code is changed to do, instead of the added free() here a: if (opts->strategy) opts->strategy = xstrdup("another leak"); We get a couple of stacktraces from -fsanitize=leak showing how we ended up clobbering the already allocated value, i.e.: Direct leak of 6 byte(s) in 1 object(s) allocated from: #0 0x7f2e8cd45545 in __interceptor_malloc ../../../../src/libsanitizer/lsan/lsan_interceptors.cpp:75 #1 0x7f2e8cb0fcaa in __GI___strdup string/strdup.c:42 #2 0x6c4778 in xstrdup wrapper.c:39 #3 0x66bcb8 in read_strategy_opts sequencer.c:2902 #4 0x66bf7b in read_populate_opts sequencer.c:2969 #5 0x6723f9 in sequencer_continue sequencer.c:5063 #6 0x4a4f74 in run_sequencer_rebase builtin/rebase.c:348 #7 0x4a64c8 in run_specific_rebase builtin/rebase.c:753 #8 0x4a9b8b in cmd_rebase builtin/rebase.c:1824 #9 0x407a32 in run_builtin git.c:466 #10 0x407e0a in handle_builtin git.c:721 #11 0x40803d in run_argv git.c:788 #12 0x40850f in cmd_main git.c:923 #13 0x4eee79 in main common-main.c:57 #14 0x7f2e8ca9f209 in __libc_start_call_main ../sysdeps/nptl/libc_start_call_main.h:58 #15 0x7f2e8ca9f2bb in __libc_start_main_impl ../csu/libc-start.c:389 #16 0x405fd0 in _start (git+0x405fd0) Direct leak of 4 byte(s) in 1 object(s) allocated from: #0 0x7f2e8cd45545 in __interceptor_malloc ../../../../src/libsanitizer/lsan/lsan_interceptors.cpp:75 #1 0x7f2e8cb0fcaa in __GI___strdup string/strdup.c:42 #2 0x6c4778 in xstrdup wrapper.c:39 #3 0x4a3c31 in xstrdup_or_null git-compat-util.h:1169 #4 0x4a447a in get_replay_opts builtin/rebase.c:163 #5 0x4a4f5b in run_sequencer_rebase builtin/rebase.c:346 #6 0x4a64c8 in run_specific_rebase builtin/rebase.c:753 #7 0x4a9b8b in cmd_rebase builtin/rebase.c:1824 #8 0x407a32 in run_builtin git.c:466 #9 0x407e0a in handle_builtin git.c:721 #10 0x40803d in run_argv git.c:788 #11 0x40850f in cmd_main git.c:923 #12 0x4eee79 in main common-main.c:57 #13 0x7f2e8ca9f209 in __libc_start_call_main ../sysdeps/nptl/libc_start_call_main.h:58 #14 0x7f2e8ca9f2bb in __libc_start_main_impl ../csu/libc-start.c:389 #15 0x405fd0 in _start (git+0x405fd0) This can be seen in e.g. the 4th test of "t3404-rebase-interactive.sh". In the larger picture the ownership of the "struct replay_opts" is quite a mess, e.g. in this case rebase.c's static "get_replay_opts()" function partially creates it, but nothing in rebase.c will free() it. The structure is "mostly owned" by the sequencer API, but it also expects to get these partially populated versions of it. It would be better to have rebase keep track of what it allocated, and free() that, and to pass that as a "const" to the sequencer API, which would copy what it needs to its own version, and to free() that. But doing so is a much larger change, and however messy the ownership boundary is here is consistent with what we're doing already, so let's just free() this to fix the leak. Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Taylor Blau <me@ttaylorr.com>

When t5583-push-branches.sh was originally introduced via 425b4d7 (push: introduce '--branches' option, 2023-05-06), it was not leak-free. In fact, the test did not even run correctly until 022fbb6 (t5583: fix shebang line, 2023-05-12), but after applying that patch, we see a failure at t5583.8: ==2529087==ERROR: LeakSanitizer: detected memory leaks Direct leak of 384 byte(s) in 1 object(s) allocated from: #0 0x7fb536330986 in __interceptor_realloc ../../../../src/libsanitizer/lsan/lsan_interceptors.cpp:98 #1 0x55e07606cbf9 in xrealloc wrapper.c:140 #2 0x55e075fb6cb3 in prio_queue_put prio-queue.c:42 #3 0x55e075ec81cb in get_reachable_subset commit-reach.c:917 #4 0x55e075fe9cce in add_missing_tags remote.c:1518 #5 0x55e075fea1e4 in match_push_refs remote.c:1665 #6 0x55e076050a8e in transport_push transport.c:1378 #7 0x55e075e2eb74 in push_with_options builtin/push.c:401 #8 0x55e075e2edb0 in do_push builtin/push.c:458 #9 0x55e075e2ff7a in cmd_push builtin/push.c:702 #10 0x55e075d8aaf0 in run_builtin git.c:452 #11 0x55e075d8af08 in handle_builtin git.c:706 #12 0x55e075d8b12c in run_argv git.c:770 #13 0x55e075d8b6a0 in cmd_main git.c:905 #14 0x55e075e81f07 in main common-main.c:60 #15 0x7fb5360ab6c9 in __libc_start_call_main ../sysdeps/nptl/libc_start_call_main.h:58 #16 0x7fb5360ab784 in __libc_start_main_impl ../csu/libc-start.c:360 #17 0x55e075d88f40 in _start (git+0x1ff40) (BuildId: 38ad998b85a535e786129979443630d025ec2453) SUMMARY: LeakSanitizer: 384 byte(s) leaked in 1 allocation(s). This leak was addressed independently via 68b5117 (commit-reach: fix memory leak in get_reachable_subset(), 2023-06-03), which makes t5583 leak-free. But t5583 was not in the tree when 68b5117 was written, and the two only met after the latter was merged back in via 693bde4 (Merge branch 'mh/commit-reach-get-reachable-plug-leak', 2023-06-20). At that point, t5583 was leak-free. Let's mark it as such accordingly. Signed-off-by: Taylor Blau <me@ttaylorr.com> Acked-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>

The t5309 script triggers a racy false positive with SANITIZE=leak on a multi-core system. Running with "--stress --run=6" usually fails within 10 seconds or so for me, complaining with something like: + git index-pack --fix-thin --stdin fatal: REF_DELTA at offset 46 already resolved (duplicate base 01d7713666f4de822776c7622c10f1b07de280dc?) ================================================================= ==3904583==ERROR: LeakSanitizer: detected memory leaks Direct leak of 32 byte(s) in 1 object(s) allocated from: #0 0x7fa790d01986 in __interceptor_realloc ../../../../src/libsanitizer/lsan/lsan_interceptors.cpp:98 #1 0x7fa790add769 in __pthread_getattr_np nptl/pthread_getattr_np.c:180 #2 0x7fa790d117c5 in __sanitizer::GetThreadStackTopAndBottom(bool, unsigned long*, unsigned long*) ../../../../src/libsanitizer/sanitizer_common/sanitizer_linux_libcdep.cpp:150 #3 0x7fa790d11957 in __sanitizer::GetThreadStackAndTls(bool, unsigned long*, unsigned long*, unsigned long*, unsigned long*) ../../../../src/libsanitizer/sanitizer_common/sanitizer_linux_libcdep.cpp:598 #4 0x7fa790d03fe8 in __lsan::ThreadStart(unsigned int, unsigned long long, __sanitizer::ThreadType) ../../../../src/libsanitizer/lsan/lsan_posix.cpp:51 #5 0x7fa790d013fd in __lsan_thread_start_func ../../../../src/libsanitizer/lsan/lsan_interceptors.cpp:440 #6 0x7fa790adc3eb in start_thread nptl/pthread_create.c:444 #7 0x7fa790b5ca5b in clone3 ../sysdeps/unix/sysv/linux/x86_64/clone3.S:81 SUMMARY: LeakSanitizer: 32 byte(s) leaked in 1 allocation(s). Aborted What happens is this: 0. We construct a bogus pack with a duplicate object in it and trigger index-pack. 1. We spawn a bunch of worker threads to resolve deltas (on my system it is 16 threads). 2. One of the threads sees the duplicate object and bails by calling exit(), taking down all of the threads. This is expected and is the point of the test. 3. At the time exit() is called, we may still be spawning threads from the main process via pthread_create(). LSan hooks thread creation to update its book-keeping; it has to know where each thread's stack is (so it can find entry points for reachable memory). So it calls pthread_getattr_np() to get information about the new thread. That may allocate memory that must be freed with a matching call to pthread_attr_destroy(). Probably LSan does that immediately, but if you're unlucky enough, the exit() will happen while it's between those two calls, and the allocated pthread_attr_t appears as a leak. This isn't a real leak. It's not even in our code, but rather in the LSan instrumentation code. So we could just ignore it. But the false positive can cause people to waste time tracking it down. It's possibly something that LSan could protect against (e.g., cover the getattr/destroy pair with a mutex, and then in the final post-exit() check for leaks try to take the same mutex). But I don't know enough about LSan to say if that's a reasonable approach or not (or if my analysis is even completely correct). In the meantime, it's pretty easy to avoid the race by making creation of the worker threads "atomic". That is, we'll spawn all of them before letting any of them start to work. That's easy to do because we already have a work_lock() mutex for handing out that work. If the main process takes it, then all of the threads will immediately block until we've finished spawning and released it. This shouldn't make any practical difference for non-LSan runs. The thread spawning is quick, and could happen before any worker thread gets scheduled anyway. Probably other spots that use threads are subject to the same issues. But since we have to manually insert locking (and since this really is kind of a hack), let's not bother with them unless somebody experiences a similar racy false-positive in practice. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Memory sanitizer (msan) is detecting a use of an uninitialized variable (`size`) in `read_attr_from_index`: ==2268==WARNING: MemorySanitizer: use-of-uninitialized-value #0 0x5651f3416504 in read_attr_from_index git/attr.c:868:11 #1 0x5651f3415530 in read_attr git/attr.c #2 0x5651f3413d74 in bootstrap_attr_stack git/attr.c:968:6 #3 0x5651f3413d74 in prepare_attr_stack git/attr.c:1004:2 #4 0x5651f3413d74 in collect_some_attrs git/attr.c:1199:2 #5 0x5651f3413144 in git_check_attr git/attr.c:1345:2 #6 0x5651f34728da in convert_attrs git/convert.c:1320:2 #7 0x5651f3473425 in would_convert_to_git_filter_fd git/convert.c:1373:2 #8 0x5651f357a35e in index_fd git/object-file.c:2630:34 #9 0x5651f357aa15 in index_path git/object-file.c:2657:7 #10 0x5651f35db9d9 in add_to_index git/read-cache.c:766:7 #11 0x5651f35dc170 in add_file_to_index git/read-cache.c:799:9 #12 0x5651f321f9b2 in add_files git/builtin/add.c:346:7 #13 0x5651f321f9b2 in cmd_add git/builtin/add.c:565:18 #14 0x5651f321d327 in run_builtin git/git.c:474:11 #15 0x5651f321bc9e in handle_builtin git/git.c:729:3 #16 0x5651f321a792 in run_argv git/git.c:793:4 #17 0x5651f321a792 in cmd_main git/git.c:928:19 #18 0x5651f33dde1f in main git/common-main.c:62:11 The issue exists because `size` is an output parameter from `read_blob_data_from_index`, but it's only modified if `read_blob_data_from_index` returns non-NULL. The read of `size` when calling `read_attr_from_buf` unconditionally may read from an uninitialized value. `read_attr_from_buf` checks that `buf` is non-NULL before reading from `size`, but by then it's already too late: the uninitialized read will have happened already. Furthermore, there's no guarantee that the compiler won't reorder things so that it checks `size` before checking `!buf`. Make the call to `read_attr_from_buf` conditional on `buf` being non-NULL, ensuring that `size` is not read if it's never set. Signed-off-by: Kyle Lippincott <spectral@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>

It was recently reported that concurrent reads and writes may cause the reftable backend to segfault. The root cause of this is that we do not properly keep track of reftable readers across reloads. Suppose that you have a reftable iterator and then decide to reload the stack while iterating through the iterator. When the stack has been rewritten since we have created the iterator, then we would end up discarding a subset of readers that may still be in use by the iterator. The consequence is that we now try to reference deallocated memory, which of course segfaults. One way to trigger this is in t5616, where some background maintenance jobs have been leaking from one test into another. This leads to stack traces like the following one: + git -c protocol.version=0 -C pc1 fetch --filter=blob:limit=29999 --refetch origin AddressSanitizer:DEADLYSIGNAL ================================================================= ==657994==ERROR: AddressSanitizer: SEGV on unknown address 0x7fa0f0ec6089 (pc 0x55f23e52ddf9 bp 0x7ffe7bfa1700 sp 0x7ffe7bfa1700 T0) ==657994==The signal is caused by a READ memory access. #0 0x55f23e52ddf9 in get_var_int reftable/record.c:29 #1 0x55f23e53295e in reftable_decode_keylen reftable/record.c:170 #2 0x55f23e532cc0 in reftable_decode_key reftable/record.c:194 #3 0x55f23e54e72e in block_iter_next reftable/block.c:398 #4 0x55f23e5573dc in table_iter_next_in_block reftable/reader.c:240 #5 0x55f23e5573dc in table_iter_next reftable/reader.c:355 #6 0x55f23e5573dc in table_iter_next reftable/reader.c:339 #7 0x55f23e551283 in merged_iter_advance_subiter reftable/merged.c:69 #8 0x55f23e55169e in merged_iter_next_entry reftable/merged.c:123 #9 0x55f23e55169e in merged_iter_next_void reftable/merged.c:172 #10 0x55f23e537625 in reftable_iterator_next_ref reftable/generic.c:175 #11 0x55f23e2cf9c6 in reftable_ref_iterator_advance refs/reftable-backend.c:464 #12 0x55f23e2d996e in ref_iterator_advance refs/iterator.c:13 #13 0x55f23e2d996e in do_for_each_ref_iterator refs/iterator.c:452 #14 0x55f23dca6767 in get_ref_map builtin/fetch.c:623 #15 0x55f23dca6767 in do_fetch builtin/fetch.c:1659 #16 0x55f23dca6767 in fetch_one builtin/fetch.c:2133 #17 0x55f23dca6767 in cmd_fetch builtin/fetch.c:2432 #18 0x55f23dba7764 in run_builtin git.c:484 #19 0x55f23dba7764 in handle_builtin git.c:741 #20 0x55f23dbab61e in run_argv git.c:805 #21 0x55f23dbab61e in cmd_main git.c:1000 #22 0x55f23dba4781 in main common-main.c:64 #23 0x7fa0f063fc89 in __libc_start_call_main ../sysdeps/nptl/libc_start_call_main.h:58 #24 0x7fa0f063fd44 in __libc_start_main_impl ../csu/libc-start.c:360 #25 0x55f23dba6ad0 in _start (git+0xadfad0) (BuildId: 803b2b7f59beb03d7849fb8294a8e2145dd4aa27) While it is somewhat awkward that the maintenance processes survive tests in the first place, it is totally expected that reftables should work alright with concurrent writers. Seemingly they don't. The only underlying resource that we need to care about in this context is the reftable reader, which is responsible for reading a single table from disk. These readers get discarded immediately (unless reused) when calling `reftable_stack_reload()`, which is wrong. We can only close them once we know that there are no iterators using them anymore. Prepare for a fix by converting the reftable readers to be refcounted. Reported-by: Jeff King <peff@peff.net> Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>

An internal customer reported a segfault when running `git sparse-checkout set` with the `index.sparse` config enabled. I was unable to reproduce it locally, but with their help we debugged into the failing process and discovered the following stacktrace: ``` #0 0x00007ff6318fb7b0 in rehash (map=0x3dfb00d0440, newsize=1048576) at hashmap.c:125 #1 0x00007ff6318fbc66 in hashmap_add (map=0x3dfb00d0440, entry=0x3dfb5c58bc8) at hashmap.c:247 #2 0x00007ff631937a70 in hash_index_entry (istate=0x3dfb00d0400, ce=0x3dfb5c58bc8) at name-hash.c:122 #3 0x00007ff631938a2f in add_name_hash (istate=0x3dfb00d0400, ce=0x3dfb5c58bc8) at name-hash.c:638 #4 0x00007ff631a064de in set_index_entry (istate=0x3dfb00d0400, nr=8291, ce=0x3dfb5c58bc8) at sparse-index.c:255 #5 0x00007ff631a06692 in add_path_to_index (oid=0x5ff130, base=0x5ff580, path=0x3dfb4b725da "<redacted>", mode=33188, context=0x5ff570) at sparse-index.c:307 #6 0x00007ff631a3b48c in read_tree_at (r=0x7ff631c026a0 <the_repo>, tree=0x3dfb5b41f60, base=0x5ff580, depth=2, pathspec=0x5ff5a0, fn=0x7ff631a064e5 <add_path_to_index>, context=0x5ff570) at tree.c:46 #7 0x00007ff631a3b60b in read_tree_at (r=0x7ff631c026a0 <the_repo>, tree=0x3dfb5b41e80, base=0x5ff580, depth=1, pathspec=0x5ff5a0, fn=0x7ff631a064e5 <add_path_to_index>, context=0x5ff570) at tree.c:80 #8 0x00007ff631a3b60b in read_tree_at (r=0x7ff631c026a0 <the_repo>, tree=0x3dfb5b41ac8, base=0x5ff580, depth=0, pathspec=0x5ff5a0, fn=0x7ff631a064e5 <add_path_to_index>, context=0x5ff570) at tree.c:80 #9 0x00007ff631a06a95 in expand_index (istate=0x3dfb00d0100, pl=0x0) at sparse-index.c:422 #10 0x00007ff631a06cbd in ensure_full_index (istate=0x3dfb00d0100) at sparse-index.c:456 #11 0x00007ff631990d08 in index_name_stage_pos (istate=0x3dfb00d0100, name=0x3dfb0020080 "algorithm/levenshtein", namelen=21, stage=0, search_mode=EXPAND_SPARSE) at read-cache.c:556 #12 0x00007ff631990d6c in index_name_pos (istate=0x3dfb00d0100, name=0x3dfb0020080 "algorithm/levenshtein", namelen=21) at read-cache.c:566 #13 0x00007ff63180dbb5 in sanitize_paths (argc=185, argv=0x3dfb0030018, prefix=0x0, skip_checks=0) at builtin/sparse-checkout.c:756 #14 0x00007ff63180de50 in sparse_checkout_set (argc=185, argv=0x3dfb0030018, prefix=0x0) at builtin/sparse-checkout.c:860 #15 0x00007ff63180e6c5 in cmd_sparse_checkout (argc=186, argv=0x3dfb0030018, prefix=0x0) at builtin/sparse-checkout.c:1063 #16 0x00007ff6317234cb in run_builtin (p=0x7ff631ad9b38 <commands+2808>, argc=187, argv=0x3dfb0030018) at git.c:548 #17 0x00007ff6317239c0 in handle_builtin (argc=187, argv=0x3dfb0030018) at git.c:808 #18 0x00007ff631723c7d in run_argv (argcp=0x5ffdd0, argv=0x5ffd78) at git.c:877 #19 0x00007ff6317241d1 in cmd_main (argc=187, argv=0x3dfb0030018) at git.c:1017 #20 0x00007ff631838b60 in main (argc=190, argv=0x3dfb0030000) at common-main.c:64 ``` The very bottom of the stack being the `rehash()` method from `hashmap.c` as called within the `name-hash` API made me look at where these hashmaps were being used in the sparse index logic. These were being copied across indexes, which seems dangerous. Indeed, clearing these hashmaps and setting them as not initialized fixes the segfault. The second commit is a response to a test failure that happens in `t1092-sparse-checkout-compatibility.sh` where `git stash pop` starts to fail because the underlying `git checkout-index` process fails due to colliding files. Passing the `-f` flag appears to work, but it's unclear why this name-hash change causes that change in behavior.

fixup string comparison

410af44

Signed-off-by: nalla <nalla@users.noreply.github.com>

nalla mentioned this pull request Mar 3, 2015

Update to 2.3.0 git-for-windows/git#27

Merged

nalla closed this Mar 3, 2015

nalla deleted the patch-1 branch March 3, 2015 14:51

dscho pushed a commit that referenced this pull request Mar 6, 2015

Post 2.3 cycle (batch #7)

5135fef

Signed-off-by: Junio C Hamano <gitster@pobox.com>

dscho pushed a commit that referenced this pull request Dec 15, 2018

Merge pull request #7 from jeffhostetler/gvfs-status-serialize-wait

33d5dd1

status: deserialization wait

dscho pushed a commit that referenced this pull request Feb 27, 2019

Merge pull request #7 from jeffhostetler/gvfs-status-serialize-wait

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status: deserialization wait

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Merge pull request #7 from jeffhostetler/gvfs-status-serialize-wait

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status: deserialization wait

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Merge pull request #7 from jeffhostetler/gvfs-status-serialize-wait

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status: deserialization wait

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What's cooking (2021/06 #7)

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What's cooking (2021/07 #7)

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What's cooking (2021/08 #7)

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fixup string comparison #7

fixup string comparison #7

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fixup string comparison #7

fixup string comparison #7

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