From: Quentin Carbonneaux <quentin@c9x.me>
Date: Thu, 4 Feb 2021 10:13:41 +0000 (+0100)
Subject: deal safely with short inputs in ZSTD_ldm_generateSequences
X-Git-Tag: v1.4.9^2~16^2~2
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=874a590e5ceb9a08beac462ae1e3d3747ccfe17d;p=thirdparty%2Fzstd.git

deal safely with short inputs in ZSTD_ldm_generateSequences

The fuzzer CI found this bug.
---

diff --git a/lib/compress/zstd_ldm.c b/lib/compress/zstd_ldm.c
index cd6daa0a0..9292aa4d0 100644
--- a/lib/compress/zstd_ldm.c
+++ b/lib/compress/zstd_ldm.c
@@ -328,6 +328,9 @@ static size_t ZSTD_ldm_generateSequences_internal(
     } candidates[LDM_LOOKAHEAD_SPLITS];
     unsigned numSplits;
 
+    if (srcSize < minMatchLength)
+        return iend - anchor;
+
     /* Initialize the rolling hash state with the first minMatchLength bytes */
     ZSTD_ldm_gear_init(&hashState, params);
     {