Let git-mktree validate tree objects better #6
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* sv/doc-stripspace: Documentation/git-stripspace: add synopsis for --comment-lines
Remove unused code. * jc/hook-cleanup: run-command.c: retire unused run_hook_with_custom_index()
"diff-highlight" filter (in contrib/) allows its color output to be customized via configuration variables. * jk/colors: parse_color: drop COLOR_BACKGROUND macro diff-highlight: allow configurable colors parse_color: recognize "no$foo" to clear the $foo attribute parse_color: support 24-bit RGB values parse_color: refactor color storage
Correct an API anomaly. * jk/lock-ref-sha1-basic-return-errors: lock_ref_sha1_basic: do not die on locking errors
"git add --ignore-errors ..." did not ignore an error to give a file that did not exist. * mg/add-ignore-errors: add: ignore only ignored files
Some filesystems assign filemodes in a strange way, fooling then automatic "filemode trustability" check done during a new repository creation. * tb/config-core-filemode-check-on-broken-fs: init-db: improve the filemode trustability check
* jc/refer-to-t-readme-from-submitting-patches: t/README: justify why "! grep foo" is sufficient SubmittingPatches: refer to t/README for tests
* js/t5000-dont-copy-bin-sh: t5000 on Windows: do not mistake "sh.exe" as "sh"
Avoid compilation warnings on recent gcc toolchain on Cygwin. * rj/no-xopen-source-for-cygwin: git-compat-util.h: don't define _XOPEN_SOURCE on cygwin
…h-from-login' into next * dw/shell-basename-dashdash-before-stripping-leading-dash-from-login: git-sh-setup.sh: use dashdash with basename call
"git remote update --prune" to drop many refs has been optimized. * mh/simplify-repack-without-refs: sort_string_list(): rename to string_list_sort() prune_remote(): iterate using for_each_string_list_item() prune_remote(): rename local variable repack_without_refs(): make the refnames argument a string_list prune_remote(): sort delete_refs_list references en masse prune_remote(): initialize both delete_refs lists in a single loop prune_remote(): exit early if there are no stale references
"git am" learned "--message-id" option to copy the message ID of the incoming e-mail to the log message of resulting commit. * pb/am-message-id-footer: git-am: add --message-id/--no-message-id git-mailinfo: add --message-id
"git send-email" learned "--transfer-encoding" option to force a non-fault Content-Transfer-Encoding header (e.g. base64). * pb/send-email-te: git-send-email: add --transfer-encoding option git-send-email: delay creation of MIME headers
Allow "git clone --reference" to be used more safely. * jc/clone-borrow: clone: --dissociate option to mark that reference is only temporary
The report from "git checkout" on a branch that builds on another local branch by setting its branch.*.merge to branch name (not a full refname) incorrectly said that the upstream is gone. * jc/checkout-local-track-report: checkout: report upstream correctly even with loosely defined branch.*.merge
Fix long-standing bug in "diff -B -M" output. * jc/diff-b-m: diff -B -M: fix output for "copy and then rewrite" case
The commented output used to blindly add a SP before the payload line, resulting in "# \t<indented text>\n" when the payload began with a HT. Instead, produce "#\t<indented text>\n". * jc/strbuf-add-lines-avoid-sp-ht-sequence: strbuf_add_commented_lines(): avoid SP-HT sequence in commented lines
Unlike all the other hints given in the commit log editor, the list of conflicted paths were appended at the end without commented out. * jc/conflict-hint: merge & sequencer: turn "Conflicts:" hint into a comment builtin/commit.c: extract ignore_non_trailer() helper function merge & sequencer: unify codepaths that write "Conflicts:" hint builtin/merge.c: drop a parameter that is never used
The get_merge_bases*() API was easy to misuse by careless copy&paste coders, leaving object flags tainted in the commits that needed to be traversed. * jc/merge-bases: get_merge_bases(): always clean-up object flags bisect: clean flags after checking merge bases
The lockfile API can get confused which file to clean up when the process moved the $cwd after creating a lockfile. * nd/lockfile-absolute: lockfile.c: store absolute path
* br/imap-send-verbosity: imap-send: use parse options API to determine verbosity
Newer libCurl knows how to talk IMAP; "git imap-send" has been updated to use this instead of a hand-rolled OpenSSL calls. * br/imap-send-via-libcurl: git-imap-send: use libcurl for implementation
Traditionally we tried to avoid interpreting date strings given by the user as future dates, e.g. GIT_COMMITTER_DATE=2014-12-10 when used early November 2014 was taken as "October 12, 2014" because it is likely that a date in the future, December 10, is a mistake. Loosen this and do not tiebreak by future-ness of the date when (1) ISO-like format is used, and (2) the string can make sense interpreted as both y-m-d and y-d-m. * jk/approxidate-avoid-y-d-m-over-future-dates: approxidate: allow ISO-like dates far in the future pass TIME_DATE_NOW to approxidate future-check
"git interpret-trailers" learned to properly handle the "Conflicts:" block at the end. * cc/interpret-trailers-more: trailer: add test with an old style conflict block trailer: reuse ignore_non_trailer() to ignore conflict lines commit: make ignore_non_trailer() non static
The code to abbreviate an object name to its short unique prefix has been optimized when no abbreviation was requested. * mh/find-uniq-abbrev: sha1_name: avoid unnecessary sha1 lookup in find_unique_abbrev
The function sometimes returned a non-freeable memory and some other times returned a piece of memory that must be freed. * jc/exec-cmd-system-path-leak-fix: system_path(): always return free'able memory to the caller
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Includes these pull requests: #1 #6 #10 #11 msysgit#157 msysgit#212 msysgit#260 msysgit#270 Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
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Includes these pull requests: #1 #6 #10 #11 msysgit#157 msysgit#212 msysgit#260 msysgit#270 Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
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Includes these pull requests: #1 #6 #10 #11 msysgit#157 msysgit#212 msysgit#260 msysgit#270 Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
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Includes these pull requests: #1 #6 #10 #11 msysgit#157 msysgit#212 msysgit#260 msysgit#270 Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
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Includes these pull requests: #1 #6 #10 #11 msysgit#157 msysgit#212 msysgit#260 msysgit#270 Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
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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,$blob,.gitattributes
git check-attr --all file
AddressSanitizer:DEADLYSIGNAL
=================================================================
==8451==ERROR: AddressSanitizer: SEGV on unknown address 0x7f93efa00800 (pc 0x7f94f1f8f082 bp 0x7ffddb59b3a0 sp 0x7ffddb59ab28 T0)
==8451==The signal is caused by a READ memory access.
#0 0x7f94f1f8f082 (/usr/lib/libc.so.6+0x176082)
#1 0x7f94f2047d9c in __interceptor_strspn /usr/src/debug/gcc/libsanitizer/sanitizer_common/sanitizer_common_interceptors.inc:752
#2 0x560e190f7f26 in parse_attr_line attr.c:375
#3 0x560e190f9663 in handle_attr_line attr.c:660
#4 0x560e190f9ddd in read_attr_from_index attr.c:769
#5 0x560e190f9f14 in read_attr attr.c:797
#6 0x560e190fa24e in bootstrap_attr_stack attr.c:867
#7 0x560e190fa4a5 in prepare_attr_stack attr.c:902
#8 0x560e190fb5dc in collect_some_attrs attr.c:1097
#9 0x560e190fb93f in git_all_attrs attr.c:1128
#10 0x560e18e6136e in check_attr builtin/check-attr.c:67
#11 0x560e18e61c12 in cmd_check_attr builtin/check-attr.c:183
#12 0x560e18e15993 in run_builtin git.c:466
#13 0x560e18e16397 in handle_builtin git.c:721
#14 0x560e18e16b2b in run_argv git.c:788
#15 0x560e18e17991 in cmd_main git.c:926
#16 0x560e190ae2bd in main common-main.c:57
#17 0x7f94f1e3c28f (/usr/lib/libc.so.6+0x2328f)
#18 0x7f94f1e3c349 in __libc_start_main (/usr/lib/libc.so.6+0x23349)
#19 0x560e18e110e4 in _start ../sysdeps/x86_64/start.S:115
AddressSanitizer can not provide additional info.
SUMMARY: AddressSanitizer: SEGV (/usr/lib/libc.so.6+0x176082)
==8451==ABORTING
Fix this bug by converting the variable to a `size_t` instead.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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It is possible to trigger an integer overflow when parsing attribute
names when there are more than 2^31 of them for a single pattern. This
can either lead to us dying due to trying to request too many bytes:
blob=$(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>
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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>
dscho
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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>
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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>
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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>
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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>
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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>
dscho
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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>
dscho
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Includes these pull requests: #1 #6 #10 #11 msysgit#157 msysgit#212 msysgit#260 msysgit#270 Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
dscho
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Includes these pull requests: #1 #6 #10 #11 msysgit#157 msysgit#212 msysgit#260 msysgit#270 Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
dscho
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Jul 8, 2024
When performing multi-pack reuse, reuse_partial_packfile_from_bitmap() is responsible for generating an array of bitmapped_pack structs from which to perform reuse. In the multi-pack case, we loop over the MIDXs packs and copy the result of calling `nth_bitmapped_pack()` to construct the list of reusable paths. But we may also want to do pack-reuse over a single pack, either because we only had one pack to perform reuse over (in the case of single-pack bitmaps), or because we explicitly asked to do single pack reuse even with a MIDX[^1]. When this is the case, the array we generate of reusable packs contains only a single element, which is either (a) the pack attached to the single-pack bitmap, or (b) the MIDX's preferred pack. In 795006f (pack-bitmap: gracefully handle missing BTMP chunks, 2024-04-15), we refactored the reuse_partial_packfile_from_bitmap() function and stopped assigning the pack_int_id field when reusing only the MIDX's preferred pack. This results in an uninitialized read down in try_partial_reuse() like so: ==7474==WARNING: MemorySanitizer: use-of-uninitialized-value #0 0x55c5cd191dde in try_partial_reuse pack-bitmap.c:1887:8 #1 0x55c5cd191dde in reuse_partial_packfile_from_bitmap_1 pack-bitmap.c:2001:8 #2 0x55c5cd191dde in reuse_partial_packfile_from_bitmap pack-bitmap.c:2105:3 #3 0x55c5cce0bd0e in get_object_list_from_bitmap builtin/pack-objects.c:4043:3 #4 0x55c5cce0bd0e in get_object_list builtin/pack-objects.c:4156:27 #5 0x55c5cce0bd0e in cmd_pack_objects builtin/pack-objects.c:4596:3 #6 0x55c5ccc8fac8 in run_builtin git.c:474:11 which happens when try_partial_reuse() tries to call midx_pair_to_pack_pos() when it tries to reject cross-pack deltas. Avoid the uninitialized read by ensuring that the pack_int_id field is set in the single-pack reuse case by setting it to either the MIDX preferred pack's pack_int_id, or '-1', in the case of single-pack bitmaps. In the latter case, we never read the pack_int_id field, so the choice of '-1' is intentional as a "garbage in, garbage out" measure. Guard against further regressions in this area by adding a test which ensures that we do not throw out deltas from the preferred pack as "cross-pack" due to an uninitialized pack_int_id. [^1]: This can happen for a couple of reasons, either because the repository is configured with 'pack.allowPackReuse=(true|single)', or because the MIDX was generated prior to the introduction of the BTMP chunk, which contains information necessary to perform multi-pack reuse. Reported-by: Kyle Lippincott <spectral@google.com> Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
dscho
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Jul 8, 2024
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>
dscho
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Sep 13, 2024
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>
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So far, we have rudimentary parsing, but e.g. do not validate the listed filenames. Let's fix this.