Commit 2e7f3cab authored Mar 07, 2024 by Gavrilov Ilia Committed by Sasha Levin Mar 26, 2024

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



[ Upstream commit 716edc9706deb3bb2ff56e2eeb83559cea8f22db ]

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: 1da177e4 ("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>
Signed-off-by: Sasha Levin <sashal@kernel.org>

parent fb6639c7

net/ipv4/tcp.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -3451,11 +3451,11 @@ static int do_tcp_getsockopt(struct sock *sk, int level,
		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 TCP_MAXSEG:
		val = tp->mss_cache;