From: Nick Terrell <terrelln@fb.com>
Date: Sat, 30 Sep 2017 21:17:32 +0000 (-0700)
Subject: Don't `size -= 1` in ZSTD_adjustCParams()
X-Git-Tag: v1.3.2~3^2~17^2
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=c5d6dde502e4e30c7de4476e82b459361fe2f486;p=thirdparty%2Fzstd.git

Don't `size -= 1` in ZSTD_adjustCParams()

The window size could end up too small if the source size is 2^n + 1.

Credit to OSS-Fuzz
---

diff --git a/lib/compress/zstd_compress.c b/lib/compress/zstd_compress.c
index 4c2254abe..51cdeaf03 100644
--- a/lib/compress/zstd_compress.c
+++ b/lib/compress/zstd_compress.c
@@ -651,7 +651,7 @@ ZSTD_compressionParameters ZSTD_adjustCParams_internal(ZSTD_compressionParameter
 
     if (dictSize && (srcSize+1<2) /* srcSize unknown */ )
         srcSize = minSrcSize;  /* presumed small when there is a dictionary */
-    else
+    else if (srcSize == 0)
         srcSize -= 1;  /* unknown 0 => -1ULL : presumed large */
 
     /* resize windowLog if input is small enough, to use less memory */