2024-03-07 14:24:54

by Gavrilov Ilia

[permalink] [raw]
Subject: [PATCH net-next v2 2/6] 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 <[email protected]>
Signed-off-by: Gavrilov Ilia <[email protected]>
---
V2:
- reword the patch description
net/ipv4/udp.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index e474b201900f..17231c0f8830 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -2792,11 +2792,11 @@ 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);
--
2.39.2