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 cd6daa0a0c4f7e8fb66dbc37ac15edde121160a2..9292aa4d07ceb98842ee7c767318ccd9ca1973a4 100644 (file)
--- 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);
     {