From 99e2c16ea1cced34a5dc450d76287a1c3e762138 Mon Sep 17 00:00:00 2001
From: Daniel Wagner <wagi@monom.org>
Date: Tue, 11 Apr 2023 08:12:56 +0200
Subject: gdhcp: Verify and sanitize packet length first
Upstream-Status: Backport [https://git.kernel.org/pub/scm/network/connman/connman.git/patch/?id=99e2c16ea1cced34a5dc450d76287a1c3e762138]
CVE: CVE-2023-28488
Signed-off-by: Ashish Sharma <asharma@mvista.com>
gdhcp/client.c | 16 +++++++++-------
1 file changed, 9 insertions(+), 7 deletions(-)
diff --git a/gdhcp/client.c b/gdhcp/client.c
index 7efa7e45..82017692 100644
--- a/gdhcp/client.c
+++ b/gdhcp/client.c
@@ -1319,9 +1319,9 @@ static bool sanity_check(struct ip_udp_dhcp_packet *packet, int bytes)
static int dhcp_recv_l2_packet(struct dhcp_packet *dhcp_pkt, int fd,
struct sockaddr_in *dst_addr)
{
- int bytes;
struct ip_udp_dhcp_packet packet;
uint16_t check;
+ int bytes, tot_len;
memset(&packet, 0, sizeof(packet));
@@ -1329,15 +1329,17 @@ static int dhcp_recv_l2_packet(struct dhcp_packet *dhcp_pkt, int fd,
if (bytes < 0)
return -1;
- if (bytes < (int) (sizeof(packet.ip) + sizeof(packet.udp)))
- return -1;
-
- if (bytes < ntohs(packet.ip.tot_len))
+ tot_len = ntohs(packet.ip.tot_len);
+ if (bytes > tot_len) {
+ /* ignore any extra garbage bytes */
+ bytes = tot_len;
+ } else if (bytes < tot_len) {
/* packet is bigger than sizeof(packet), we did partial read */
return -1;
+ }
- /* ignore any extra garbage bytes */
- bytes = ntohs(packet.ip.tot_len);
+ if (bytes < (int) (sizeof(packet.ip) + sizeof(packet.udp)))
+ return -1;
if (!sanity_check(&packet, bytes))
return -1;
--
cgit