From cbf125408d1ca141cc1c3f8376e091e3cdde2cb2 Mon Sep 17 00:00:00 2001 From: Mikhail Zaslonko Date: Thu, 26 Jan 2023 14:14:25 +0100 Subject: [PATCH] lib/zlib: DFLTCC not writing header bits when avail_out == 0 This commit is based on: https://github.com/zlib-ng/zlib-ng/commit/ce409c6 Link: https://lkml.kernel.org/r/20230126131428.1222214-6-zaslonko@linux.ibm.com Signed-off-by: Mikhail Zaslonko Acked-by: Ilya Leoshkevich Cc: Heiko Carstens Cc: Vasily Gorbik Signed-off-by: Andrew Morton --- lib/zlib_dfltcc/dfltcc_deflate.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) diff --git a/lib/zlib_dfltcc/dfltcc_deflate.c b/lib/zlib_dfltcc/dfltcc_deflate.c index 211d344710d5..d4c92f99808e 100644 --- a/lib/zlib_dfltcc/dfltcc_deflate.c +++ b/lib/zlib_dfltcc/dfltcc_deflate.c @@ -170,13 +170,18 @@ again: 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.