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authorMikhail Zaslonko <zaslonko@linux.ibm.com>2023-02-21 14:16:17 +0100
committerAndrew Morton <akpm@linux-foundation.org>2023-02-27 17:00:14 -0800
commit1c0a0af511effbd75beffa6c5e54fd64d3563860 (patch)
tree20d214538385d9ff2e48acc748b963af3b6c1227
parent3f98c9a62c338bbe06a215c9491e6166ea39bf82 (diff)
lib/zlib: DFLTCC deflate does not write all available bits for Z_NO_FLUSH
DFLTCC deflate with Z_NO_FLUSH might generate a corrupted stream when the output buffer is not large enough to fit all the deflate output at once. The problem takes place on closing the deflate block since flush_pending() might leave some output bits not written. Similar problem for software deflate with Z_BLOCK flush option (not supported by kernel zlib deflate) has been fixed a while ago in userspace zlib but the fix never got to the kernel. Now flush_pending() flushes the bit buffer before copying out the byte buffer, in order to really flush as much as possible. Currently there are no users of DFLTCC deflate with Z_NO_FLUSH option in the kernel so the problem remained hidden for a while. This commit is based on the old zlib commit: https://github.com/madler/zlib/commit/0b828b4 Link: https://lkml.kernel.org/r/20230221131617.3369978-2-zaslonko@linux.ibm.com Signed-off-by: Mikhail Zaslonko <zaslonko@linux.ibm.com> Acked-by: Ilya Leoshkevich <iii@linux.ibm.com> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
-rw-r--r--lib/zlib_deflate/defutil.h4
1 files changed, 3 insertions, 1 deletions
diff --git a/lib/zlib_deflate/defutil.h b/lib/zlib_deflate/defutil.h
index 385333b22ec6..4ea40f5a279f 100644
--- a/lib/zlib_deflate/defutil.h
+++ b/lib/zlib_deflate/defutil.h
@@ -420,9 +420,11 @@ static inline void flush_pending(
z_streamp strm
)
{
+ unsigned len;
deflate_state *s = (deflate_state *) strm->state;
- unsigned len = s->pending;
+ bi_flush(s);
+ len = s->pending;
if (len > strm->avail_out) len = strm->avail_out;
if (len == 0) return;