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| author | Ilya Leoshkevich <iii@linux.ibm.com> | 2021-03-18 14:54:46 +0100 |
|---|---|---|
| committer | Hans Kristian Rosbach <hk-github@circlestorm.org> | 2021-03-20 23:35:48 +0100 |
| commit | f426ac9db3e0ce35c83838aa8eaf248b2b624d0a (patch) | |
| tree | a79814c5409f3dacff828d8c72f1df03e686bf7b /deflate_fast.c | |
| parent | bc33b26ca5391eb6b2c952cd032920033be27a53 (diff) | |
Restore hash_head != 0 checks
Commit bc5915e2dec7 ("Fixed unsigned integer overflow ASAN error when
hash_head > s->strstart.") removed hash_head != 0 checks in fast,
medium and slow deflate, because it improved performance [1].
Unfortunately, the attached test started failing after that.
Apparently, as the comments suggest, the code implicitly relies on
matches with the beginning of the window being skipped. So restore the
check.
[1] https://github.com/zlib-ng/zlib-ng/pull/772#issuecomment-710760300
Diffstat (limited to 'deflate_fast.c')
| -rw-r--r-- | deflate_fast.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/deflate_fast.c b/deflate_fast.c index 14718ba..1594886 100644 --- a/deflate_fast.c +++ b/deflate_fast.c @@ -48,7 +48,7 @@ Z_INTERNAL block_state deflate_fast(deflate_state *s, int flush) { * At this point we have always match length < MIN_MATCH */ - if (dist <= MAX_DIST(s) && dist > 0) { + if (dist <= MAX_DIST(s) && dist > 0 && hash_head != 0) { /* To simplify the code, we prevent matches with the string * of window index 0 (in particular we have to avoid a match * of the string with itself at the start of the input file). |