[PATCH 4.9 40/96] ipvs: Fix signed integer overflow when setsockopt timeout

Greg Kroah-Hartman
2019-03-12T17:26:47Z

[ 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 <zhangxiaoxu5@huawei.com>
Acked-by: Simon Horman <horms@verge.net.au>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
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 8382b7880b24..8037b25ddb76 100644
--- a/net/netfilter/ipvs/ip_vs_ctl.c
+++ b/net/netfilter/ipvs/ip_vs_ctl.c
@@ -2258,6 +2258,18 @@ 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