net/x25: fix incorrect parameter validation in the x25_getsockopt() function

[ Upstream commit d6eb8de2015f0c24822e47356f839167ebde2945 ]

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>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/net/x25/af_x25.c b/net/x25/af_x25.c
index 07f6206e7cb47d83b4dbace29fab3b624bcc5282..1e5152fdee589e693f9742f5defd05741f8d5994 100644 (file)
--- a/net/x25/af_x25.c
+++ b/net/x25/af_x25.c
@@ -460,12 +460,12 @@ static int x25_getsockopt(struct socket *sock, int level, int optname,
        if (get_user(len, optlen))
                goto out;
 
-       len = min_t(unsigned int, len, sizeof(int));
-
        rc = -EINVAL;
        if (len < 0)
                goto out;
 
+       len = min_t(unsigned int, len, sizeof(int));
+
        rc = -EFAULT;
        if (put_user(len, optlen))
                goto out;