fix NULL ptr arithmetic at lz4:2299

1 files changed, 7 insertions, 2 deletions

diff --git a/lib/lz4.c b/lib/lz4.c
index 9659962..62a6f6c 100644
--- a/lib/lz4.c
+++ b/lib/lz4.c
@@ -2298,8 +2298,13 @@ int LZ4_freeStreamDecode (LZ4_streamDecode_t* LZ4_stream)
 int LZ4_setStreamDecode (LZ4_streamDecode_t* LZ4_streamDecode, const char* dictionary, int dictSize)
 {
     LZ4_streamDecode_t_internal* lz4sd = &LZ4_streamDecode->internal_donotuse;
-    lz4sd->prefixSize = (size_t) dictSize;
-    lz4sd->prefixEnd = (const BYTE*) dictionary + dictSize;
+    lz4sd->prefixSize = (size_t)dictSize;
+    if (dictSize) {
+        assert(dictionary != NULL);
+        lz4sd->prefixEnd = (const BYTE*) dictionary + dictSize;
+    } else {
+        lz4sd->prefixEnd = (const BYTE*) dictionary;
+    }
     lz4sd->externalDict = NULL;
     lz4sd->extDictSize  = 0;
     return 1;