From: Junio C Hamano <junkio@cox.net>
Date: Sat, 28 May 2005 19:22:38 +0000 (-0700)
Subject: [PATCH] Fix count-delta overcounting
X-Git-Tag: v0.99~420
X-Git-Url: https://git.verplant.org/?a=commitdiff_plain;h=8b7d510fb182ca40bd0f905bb2f5543b0d9549de;p=git.git

[PATCH] Fix count-delta overcounting

The count-delta routine sometimes overcounted the copied source
material which resulted in unsigned int wraparound.

Signed-off-by: Junio C Hamano <junkio@cox.net>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
---

diff --git a/count-delta.c b/count-delta.c
index 3bcc205f..e10c832a 100644
--- a/count-delta.c
+++ b/count-delta.c
@@ -88,5 +88,8 @@ unsigned long count_delta(void *delta_buf, unsigned long delta_size)
 	/* delete size is what was _not_ copied from source.
 	 * edit size is that and literal additions.
 	 */
+	if (src_size + added_literal < copied_from_source)
+		/* we ended up overcounting and underflowed */
+		return 0;
 	return (src_size - copied_from_source) + added_literal;
 }