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| author | Andrzej Hunt <andrzej@ahunt.org> | 2021-06-04 18:25:19 +0200 |
|---|---|---|
| committer | Edward Thomson <ethomson@edwardthomson.com> | 2022-07-12 14:27:46 -0400 |
| commit | 39ba0ee6045a68e657e074d8290b4b77baae72c0 (patch) | |
| tree | 7c579ccd17fcbd6c2e6d1f6339582a81a9488288 /deps | |
| parent | 6febb7d7670cc1f2b112c1f1540cd872cb208f37 (diff) | |
| download | libgit2-39ba0ee6045a68e657e074d8290b4b77baae72c0.tar.gz | |
zlib: slide_hash: add MSAN annotation to suppress known read from uninitialised memory
slide_hash knowingly reads (possibly) uninitialised memory, see comment
lower down about prev[n] potentially being garbage. In this case, the
result is never used - so we don't care about MSAN complaining about
this read.
By adding the no_sanitize("memory") attribute, clients of zlib won't
see this (unnecessary) error when building and running with
MemorySanitizer. An alternative approach is for clients to build zlib
with -fsanitize-ignorelist=... where the ignorelist contains something
like 'fun:slide_hash'. But that's more work and needs to be redone
for any and all CI systems running a given project with MSAN. Adding
this annotation to zlib's sources is overall more convenient - but
also won't affect non-MSAN builds.
This specific issue was found while running git's test suite, but has
also been reported by other clients, see e.g. #518.
Diffstat (limited to 'deps')
| -rw-r--r-- | deps/zlib/deflate.c | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/deps/zlib/deflate.c b/deps/zlib/deflate.c index 799fb93cc..feacd7832 100644 --- a/deps/zlib/deflate.c +++ b/deps/zlib/deflate.c @@ -201,6 +201,11 @@ local const config configuration_table[10] = { * bit values at the expense of memory usage). We slide even when level == 0 to * keep the hash table consistent if we switch back to level > 0 later. */ +#if defined(__has_feature) +# if __has_feature(memory_sanitizer) +__attribute__((no_sanitize("memory"))) +# endif +#endif local void slide_hash(s) deflate_state *s; { |