From: Michael Brown <mcb30@ipxe.org>
Date: Tue, 21 Mar 2017 12:57:36 +0000 (+0200)
Subject: [slam] Avoid NULL pointer dereference in slam_pull_value()
X-Git-Tag: v1.20.1~273
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=64de7dc7fd06470424bb4c3ea537f542c46895c4;p=thirdparty%2Fipxe.git

[slam] Avoid NULL pointer dereference in slam_pull_value()

Signed-off-by: Michael Brown <mcb30@ipxe.org>
---

diff --git a/src/net/udp/slam.c b/src/net/udp/slam.c
index 61dd7d985..c165b4fb9 100644
--- a/src/net/udp/slam.c
+++ b/src/net/udp/slam.c
@@ -400,12 +400,16 @@ static int slam_pull_value ( struct slam_request *slam,
 		return -EINVAL;
 	}
 
-	/* Read value */
+	/* Strip value */
 	iob_pull ( iobuf, len );
-	*value = ( *data & 0x1f );
-	while ( --len ) {
-		*value <<= 8;
-		*value |= *(++data);
+
+	/* Read value, if applicable */
+	if ( value ) {
+		*value = ( *data & 0x1f );
+		while ( --len ) {
+			*value <<= 8;
+			*value |= *(++data);
+		}
 	}
 
 	return 0;