From 3f2b248cadaa142508e8eacffe691416e4396b6c Mon Sep 17 00:00:00 2001 From: Eric Dumazet <edumazet@google.com> Date: Fri, 2 Dec 2016 09:44:53 -0800 Subject: [PATCH] UPSTREAM: net: avoid signed overflows for SO_{SND|RCV}BUFFORCE (cherry picked from commit b98b0bc8c431e3ceb4b26b0dfc8db509518fb290) 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. Change-Id: I2b621c28c02267af5b34a379b2970fe5fb61a4f6 Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: Andrey Konovalov <andreyknvl@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Bug: 33363517 --- 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 9bc833f00913..4e3d16d8412c 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -727,7 +727,7 @@ 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; @@ -763,7 +763,7 @@ 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: -- GitLab