From: Ilya Leoshkevich <iii@linux.ibm.com>
Date: Thu, 13 Aug 2020 09:55:01 +0000 (+0200)
Subject: Fix DFLTCC not writing header bits when avail_out == 0
X-Git-Tag: 1.9.9-b1~82
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=ce409c6aa617208338465363bdbd1e2533de2bec;p=thirdparty%2Fzlib-ng.git

Fix DFLTCC not writing header bits when avail_out == 0
---

diff --git a/arch/s390/dfltcc_deflate.c b/arch/s390/dfltcc_deflate.c
index 4692789f8..4db18fe40 100644
--- a/arch/s390/dfltcc_deflate.c
+++ b/arch/s390/dfltcc_deflate.c
@@ -162,13 +162,18 @@ again:
             send_eobs(strm, param);
             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.