Commit 1bd08e53 authored Mar 07, 2024 by Gavrilov Ilia Committed by Sasha Levin Mar 26, 2024

l2tp: fix incorrect parameter validation in the pppol2tp_getsockopt() function



[ Upstream commit 955e9876ba4ee26eeaab1b13517f5b2c88e73d55 ]

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: 3557baab ("[L2TP]: PPP over L2TP driver core")
Reviewed-by: Tom Parkin <tparkin@katalix.com>
Signed-off-by: Gavrilov Ilia <Ilia.Gavrilov@infotecs.ru>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>

parent 2e7f3cab

net/l2tp/l2tp_ppp.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -1375,11 +1375,11 @@ static int pppol2tp_getsockopt(struct socket *sock, 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));

		err = -ENOTCONN;
		if (sk->sk_user_data == NULL)
		goto end;