From: Gavrilov Ilia <Ilia.Gavrilov@infotecs.ru>
Date: Thu, 7 Mar 2024 14:23:50 +0000 (+0000)
Subject: udp: fix incorrect parameter validation in the udp_lib_getsockopt() function
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=4bb3ba7b74fceec6f558745b25a43c6521cf5506;p=linux.git

udp: fix incorrect parameter validation in the udp_lib_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")
Reviewed-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Gavrilov Ilia <Ilia.Gavrilov@infotecs.ru>
Signed-off-by: David S. Miller <davem@davemloft.net>
---

diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 2beabf5b2d862..43ec4812b60ea 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -2791,11 +2791,11 @@ int udp_lib_getsockopt(struct sock *sk, int level, int optname,
 	if (get_user(len, optlen))
 		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 UDP_CORK:
 		val = udp_test_bit(CORK, sk);