From: Eric Dumazet <edumazet@xxxxxxxxxx>
CAP_NET_ADMIN users should not be allowed to set negative
sk_sndbuf or sk_rcvbuf values, as it can lead to various memory
corruptions, crashes, OOM...
Note that before commit 82981930125a ("net: cleanups in
sock_setsockopt()"), the bug was even more serious, since SO_SNDBUF
and SO_RCVBUF were vulnerable.
This needs to be backported to all known linux kernels.
Again, many thanks to syzkaller team for discovering this gem.
Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Reported-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
(cherry picked from commit b98b0bc8c431e3ceb4b26b0dfc8db509518fb290)
Signed-off-by: Amit Pundir <amit.pundir@xxxxxxxxxx>
---
net/core/sock.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/net/core/sock.c b/net/core/sock.c
index 3b3734f81e64..7bcd07e7eeed 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -733,7 +733,7 @@ int sock_setsockopt(struct socket *sock, int level, int optname,
val = min_t(u32, val, sysctl_wmem_max);
set_sndbuf:
sk->sk_userlocks |= SOCK_SNDBUF_LOCK;
- sk->sk_sndbuf = max_t(u32, val * 2, SOCK_MIN_SNDBUF);
+ sk->sk_sndbuf = max_t(int, val * 2, SOCK_MIN_SNDBUF);
/* Wake up sending tasks if we upped the value. */
sk->sk_write_space(sk);
break;
@@ -769,7 +769,7 @@ set_rcvbuf:
* returning the value we actually used in getsockopt
* is the most desirable behavior.
*/
- sk->sk_rcvbuf = max_t(u32, val * 2, SOCK_MIN_RCVBUF);
+ sk->sk_rcvbuf = max_t(int, val * 2, SOCK_MIN_RCVBUF);
break;
case SO_RCVBUFFORCE:
--
2.7.4