From: Alan Jenkins <alan-jenkins@tuffmail.co.uk>
Date: Thu, 28 May 2009 16:59:06 +0000 (+0100)
Subject: udevd: queue-export - fix crash
X-Git-Tag: 174~1024
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=542aeeb48ab002c6136885f99aa23870f8ffa25b;p=systemd

udevd: queue-export - fix crash

The math in skip_to() was the wrong way round and allocated a
variable size array on the stack with a massively negative size.

Signed-off-by: Alan Jenkins <alan-jenkins@tuffmail.co.uk>
---

diff --git a/udev/lib/libudev-queue-export.c b/udev/lib/libudev-queue-export.c
index ddb1974d..a36ff515 100644
--- a/udev/lib/libudev-queue-export.c
+++ b/udev/lib/libudev-queue-export.c
@@ -115,8 +115,8 @@ static int skip_to(FILE *file, long offset)
 
 	/* fseek may drop buffered data, avoid it for small seeks */
 	old_offset = ftell(file);
-	if (offset > old_offset && old_offset - offset <= BUFSIZ) {
-		size_t skip_bytes = old_offset - offset;
+	if (offset > old_offset && offset - old_offset <= BUFSIZ) {
+		size_t skip_bytes = offset - old_offset;
 		char buf[skip_bytes];
 
 		if (fread(buf, skip_bytes, 1, file) != skip_bytes)