diff options
| author | Ian Lance Taylor <iant@golang.org> | 2022-04-05 16:04:09 -0700 |
|---|---|---|
| committer | Ian Lance Taylor <iant@golang.org> | 2022-04-05 16:09:34 -0700 |
| commit | 6be9d752142a03830e4202bd73f2765510ff9314 (patch) | |
| tree | f9a48612019f56acdfdc7bd8b6397e2b102fc746 /libbacktrace | |
| parent | 0b5723d74f3a731380f78dc1a02a2376951388cf (diff) | |
libbacktrace: don't skip initial aligned byte in uncompressed block
Patch from Rui Ueyama, who says:
libbacktrace occasionally fails to decompress compressed debug info
even though the sections contain valid zlib streams. The cause of the
issue is an off-by-one error.
If a zlib data block is a plain data (uncompressed data), the next two
bytes contain the size of the block. These two bytes value is byte-
aligned, so if we read-ahead more than 8 bits, we need to unread it.
So, the correct condition to determine whether or not we need to
unread a byte is bits >= 8 and not bits > 8. Due to this error,
if the last read bits happened to end at a byte boundary, the next
byte would be skipped. That caused the decompression failure.
This bug was originally reported against the mold linker.
rui314/mold#402
* elf.c (elf_zlib_inflate): Don't skip initial aligned byte in
uncompressed block.
Diffstat (limited to 'libbacktrace')
| -rw-r--r-- | libbacktrace/elf.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/libbacktrace/elf.c b/libbacktrace/elf.c index 5c7c21a8da7..8b82dd45875 100644 --- a/libbacktrace/elf.c +++ b/libbacktrace/elf.c @@ -1796,7 +1796,7 @@ elf_zlib_inflate (const unsigned char *pin, size_t sin, uint16_t *zdebug_table, /* An uncompressed block. */ /* If we've read ahead more than a byte, back up. */ - while (bits > 8) + while (bits >= 8) { --pin; bits -= 8; |