From: Nick Terrell <terrelln@meta.com>
Date: Mon, 20 Nov 2023 20:04:30 +0000 (-0800)
Subject: [huf] Fix null pointer addition
X-Git-Tag: v1.5.6^2~99
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=dd4de1dd7a78ccff933025cf1de08a75d310802b;p=thirdparty%2Fzstd.git

[huf] Fix null pointer addition

`HUF_DecompressFastArgs_init()` was adding 0 to NULL. Fix it by exiting
early for empty outputs. This is no change in behavior, because the
function was already exiting 0 in this case, just slightly later.
---

diff --git a/lib/decompress/huf_decompress.c b/lib/decompress/huf_decompress.c
index b8795efb5..0c43c656d 100644
--- a/lib/decompress/huf_decompress.c
+++ b/lib/decompress/huf_decompress.c
@@ -203,6 +203,11 @@ static size_t HUF_DecompressFastArgs_init(HUF_DecompressFastArgs* args, void* ds
     if (!MEM_isLittleEndian() || MEM_32bits())
         return 0;
 
+    /* Avoid nullptr addition */
+    if (dstSize == 0)
+        return 0;
+    assert(dst != NULL);
+
     /* strict minimum : jump table + 1 byte per stream */
     if (srcSize < 10)
         return ERROR(corruption_detected);