From: Andrew Tridgell <andrew@tridgell.net>
Date: Tue, 30 Dec 2025 05:21:41 +0000 (+1100)
Subject: fix uninitialized buf1 in get_checksum2() MD4 path
X-Git-Tag: v3.4.2~23
X-Git-Url: http://git.ipfire.org/gitweb/?a=commitdiff_plain;h=c98f9d1f68288fdd4dd6e07bfc4cc750b31f4333;p=thirdparty%2Frsync.git

fix uninitialized buf1 in get_checksum2() MD4 path

The static buf1 pointer was only allocated when len > len1, but on
first call with len == 0, this condition is false (0 > 0), leaving
buf1 NULL when passed to memcpy().

Fixes #673
---

diff --git a/checksum.c b/checksum.c
index 66e80896..6f0f95ab 100644
--- a/checksum.c
+++ b/checksum.c
@@ -366,9 +366,8 @@ void get_checksum2(char *buf, int32 len, char *sum)
 
 		mdfour_begin(&m);
 
-		if (len > len1) {
-			if (buf1)
-				free(buf1);
+		if (len > len1 || !buf1) {
+			free(buf1);
 			buf1 = new_array(char, len+4);
 			len1 = len;
 		}