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authorEric Dumazet <edumazet@google.com>2016-12-02 09:44:53 -0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2016-12-10 19:07:24 +0100
commit77125815f058d587cac9217ac2c468038a7285c4 (patch)
treee907ccf617a5f76cf17195e0b195da3264d38b8b /net
parent6e682c528b3ef046a03994b076d832b2ac029042 (diff)
net: avoid signed overflows for SO_{SND|RCV}BUFFORCE
[ Upstream 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. Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: Andrey Konovalov <andreyknvl@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'net')
-rw-r--r--net/core/sock.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/net/core/sock.c b/net/core/sock.c
index 88f017854509..f4c0917e66b5 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -745,7 +745,7 @@ 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;
@@ -781,7 +781,7 @@ 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: