net: avoid signed overflows for SO_{SND|RCV}BUFFORCE
authorEric Dumazet <edumazet@google.com>
Fri, 2 Dec 2016 17:44:53 +0000 (09:44 -0800)
committerDavid S. Miller <davem@davemloft.net>
Fri, 2 Dec 2016 19:10:14 +0000 (14:10 -0500)
commitb98b0bc8c431e3ceb4b26b0dfc8db509518fb290
tree1df6d58e0f2c836a2808658830a3425e169645e6
parent5b01014759991887b1e450c9def01e58c02ab81b
net: avoid signed overflows for SO_{SND|RCV}BUFFORCE

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>
net/core/sock.c