From: Gavrilov Ilia <Ilia.Gavrilov@infotecs.ru>
Date: Thu, 7 Mar 2024 14:23:49 +0000 (+0000)
Subject: tcp: fix incorrect parameter validation in the do_tcp_getsockopt() function
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=716edc9706deb3bb2ff56e2eeb83559cea8f22db;p=linux.git

tcp: fix incorrect parameter validation in the do_tcp_getsockopt() function

The 'len' variable can't be negative when assigned the result of
'min_t' because all 'min_t' parameters are cast to unsigned int,
and then the minimum one is chosen.

To fix the logic, check 'len' as read from 'optlen',
where the types of relevant variables are (signed) int.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Gavrilov Ilia <Ilia.Gavrilov@infotecs.ru>
Reviewed-by: Jason Xing <kerneljasonxing@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---

diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index c5b83875411ae..b091149742b1d 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -4011,11 +4011,11 @@ int do_tcp_getsockopt(struct sock *sk, int level,
 	if (copy_from_sockptr(&len, optlen, sizeof(int)))
 		return -EFAULT;
 
-	len = min_t(unsigned int, len, sizeof(int));
-
 	if (len < 0)
 		return -EINVAL;
 
+	len = min_t(unsigned int, len, sizeof(int));
+
 	switch (optname) {
 	case TCP_MAXSEG:
 		val = tp->mss_cache;