[PATCH 6.1 229/451] net/x25: fix incorrect parameter validation in the x25_getsockopt() function

[Sasha Levin]

From: Gavrilov Ilia <Ilia.Gavrilov@xxxxxxxxxxx>

[ 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@xxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 net/x25/af_x25.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/x25/af_x25.c b/net/x25/af_x25.c
index 5c7ad301d742e..5a8b2ea56564e 100644
--- 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;
-- 
2.43.0