From: Ben Pfaff <blp@nicira.com>
Date: Fri, 9 Jan 2009 01:06:19 +0000 (-0800)
Subject: datapath: Avoid pointer arithmetic on possibly-NULL pointer.
X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=4c878f1fe3108ab0c97048a8ddc47db10b3d4407;p=openvswitch

datapath: Avoid pointer arithmetic on possibly-NULL pointer.

Pointer arithmetic on a null pointer yields undefined behavior, even
though it doesn't really matter in the real world (normally).

Found by Chris Eagle via Fortify.
---

diff --git a/datapath/datapath.c b/datapath/datapath.c
index 1043742e..7f69d478 100644
--- a/datapath/datapath.c
+++ b/datapath/datapath.c
@@ -1927,7 +1927,11 @@ static void dp_uninit_netlink(void)
 static void set_desc(void)
 {
 	const char *uuid = dmi_get_system_info(DMI_PRODUCT_UUID);
-	const char *uptr = uuid + 24;
+	const char *vendor = dmi_get_system_info(DMI_SYS_VENDOR);
+	const char *name = dmi_get_system_info(DMI_PRODUCT_NAME);
+	const char *version = dmi_get_system_info(DMI_PRODUCT_VERSION);
+	const char *serial = dmi_get_system_info(DMI_PRODUCT_SERIAL);
+	const char *uptr;
 
 	if (!uuid || *uuid == '\0' || strlen(uuid) != 36) 
 		return;
@@ -1938,6 +1942,7 @@ static void set_desc(void)
 		return;
 
 	/* Only set if the UUID is from Nicira. */
+	uptr = uuid + 24;
 	if (strncmp(uptr, NICIRA_OUI_STR, strlen(NICIRA_OUI_STR)))
 		return;
 
diff --git a/datapath/dp_dev.c b/datapath/dp_dev.c
index cec7fbfa..2c99d602 100644
--- a/datapath/dp_dev.c
+++ b/datapath/dp_dev.c
@@ -130,7 +130,7 @@ static void
 set_uuid_mac(struct net_device *netdev)
 {
 	const char *uuid = dmi_get_system_info(DMI_PRODUCT_UUID);
-	const char *uptr = uuid + 24;
+	const char *uptr;
 	uint8_t mac[ETH_ALEN];
 	int i;
 
@@ -144,6 +144,7 @@ set_uuid_mac(struct net_device *netdev)
 
 	/* Pull out the embedded MAC address.  The kernel's sscanf doesn't
 	 * support field widths on hex digits, so we use this hack. */
+	uptr = uuid + 24;
 	for (i=0; i<ETH_ALEN; i++) {
 		unsigned char d[3];