Subject: [PATCH AUTOSEL 4.14 08/45] ipvs: Fix signed integer overflow when setsockopt timeout

From: Sasha Levin <[email-masked]>
Date: Sat, 23 Feb 2019 16:07:58 -0500

From: ZhangXiaoxu <[email-masked]>

[ Upstream commit 53ab60baa1ac4f20b080a22c13b77b6373922fd7 ]

There is a UBSAN bug report as below:
UBSAN: Undefined behaviour in net/netfilter/ipvs/ip_vs_ctl.c:2227:21
signed integer overflow:
-2147483647 * 1000 cannot be represented in type 'int'

Reproduce program:
	#include <stdio.h>
	#include <sys/types.h>
	#include <sys/socket.h>

	#define IPPROTO_IP 0
	#define IPPROTO_RAW 255

	#define IP_VS_BASE_CTL		(64+1024+64)
	#define IP_VS_SO_SET_TIMEOUT	(IP_VS_BASE_CTL+10)

	/* The argument to IP_VS_SO_GET_TIMEOUT */
	struct ipvs_timeout_t {
		int tcp_timeout;
		int tcp_fin_timeout;
		int udp_timeout;
	};

	int main() {
		int ret = -1;
		int sockfd = -1;
		struct ipvs_timeout_t to;

		sockfd = socket(AF_INET, SOCK_RAW, IPPROTO_RAW);
		if (sockfd == -1) {
			printf("socket init error\n");
			return -1;
		}

		to.tcp_timeout = -2147483647;
		to.tcp_fin_timeout = -2147483647;
		to.udp_timeout = -2147483647;

		ret = setsockopt(sockfd,
				 IPPROTO_IP,
				 IP_VS_SO_SET_TIMEOUT,
				 (char *)(&to),
				 sizeof(to));

		printf("setsockopt return %d\n", ret);
		return ret;
	}

Return -EINVAL if the timeout value is negative or max than 'INT_MAX / HZ'.

Signed-off-by: ZhangXiaoxu <[email-masked]>
Acked-by: Simon Horman <[email-masked]>
Signed-off-by: Pablo Neira Ayuso <[email-masked]>
Signed-off-by: Sasha Levin <[email-masked]>
---
 net/netfilter/ipvs/ip_vs_ctl.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/net/netfilter/ipvs/ip_vs_ctl.c b/net/netfilter/ipvs/ip_vs_ctl.c
index 2f45c3ce77ef2..dff4ead3d117c 100644
--- a/net/netfilter/ipvs/ip_vs_ctl.c
+++ b/net/netfilter/ipvs/ip_vs_ctl.c
@@ -2252,6 +2252,18 @@ static int ip_vs_set_timeout(struct netns_ipvs *ipvs, struct ip_vs_timeout_user
 		  u->tcp_fin_timeout,
 		  u->udp_timeout);
 
+#ifdef CONFIG_IP_VS_PROTO_TCP
+	if (u->tcp_timeout < 0 || u->tcp_timeout > (INT_MAX / HZ) ||
+	    u->tcp_fin_timeout < 0 || u->tcp_fin_timeout > (INT_MAX / HZ)) {
+		return -EINVAL;
+	}
+#endif
+
+#ifdef CONFIG_IP_VS_PROTO_UDP
+	if (u->udp_timeout < 0 || u->udp_timeout > (INT_MAX / HZ))
+		return -EINVAL;
+#endif
+
 #ifdef CONFIG_IP_VS_PROTO_TCP
 	if (u->tcp_timeout) {
 		pd = ip_vs_proto_data_get(ipvs, IPPROTO_TCP);
-- 
2.19.1