From 52baf9878b65872a7fc735d7fae3350ea9f30646 Mon Sep 17 00:00:00 2001
From: Jann Horn <jannh@google.com>
Date: Wed, 20 Feb 2019 22:34:54 +0100
Subject: [PATCH] net: socket: add check for negative optlen in compat
setsockopt
__sys_setsockopt() already checks for `optlen < 0`. Add an equivalent check
to the compat path for robustness. This has to be `> INT_MAX` instead of
`< 0` because the signedness of `optlen` is different here.
Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
net/compat.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/net/compat.c b/net/compat.c
index 959d1c51826d8..3d348198004ff 100644
--- a/net/compat.c
+++ b/net/compat.c
@@ -388,8 +388,12 @@ static int __compat_sys_setsockopt(int fd, int level, int optname,
char __user *optval, unsigned int optlen)
{
int err;
- struct socket *sock = sockfd_lookup(fd, &err);
+ struct socket *sock;
+
+ if (optlen > INT_MAX)
+ return -EINVAL;
+ sock = sockfd_lookup(fd, &err);
if (sock) {
err = security_socket_setsockopt(sock, level, optname);
if (err) {
--
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