lib/zlib: DFLTCC not writing header bits when avail_out == 0

This commit is based on: zlib-ng/zlib-ng@ce409c6 Link: https://lkml.kernel.org/r/[email protected] Signed-off-by: Mikhail Zaslonko <[email protected]> Acked-by: Ilya Leoshkevich <[email protected]> Cc: Heiko Carstens <[email protected]> Cc: Vasily Gorbik <[email protected]> Signed-off-by: Andrew Morton <[email protected]>
torvalds · Feb 3, 2023 · cbf1254 · cbf1254
1 parent 0dbae46
commit cbf1254
Showing 1 changed file with 9 additions and 4 deletions.
diff --git a/lib/zlib_dfltcc/dfltcc_deflate.c b/lib/zlib_dfltcc/dfltcc_deflate.c
@@ -170,13 +170,18 @@ int dfltcc_deflate(
  param->bcf = 0;
  dfltcc_state->block_threshold =
  strm->total_in + dfltcc_state->block_size;
- if (strm->avail_out == 0) {
- *result = need_more;
- return 1;
- }
  }
  }
 
+ /* No space for compressed data. If we proceed, dfltcc_cmpr() will return
+ * DFLTCC_CC_OP1_TOO_SHORT without buffering header bits, but we will still
+ * set BCF=1, which is wrong. Avoid complications and return early.
+ */
+ if (strm->avail_out == 0) {
+ *result = need_more;
+ return 1;
+ }
+
  /* The caller gave us too much data. Pass only one block worth of
  * uncompressed data to DFLTCC and mask the rest, so that on the next
  * iteration we start a new block.