Messages in this thread Patch in this message | | | From | Ben Hutchings <> | Date | Wed, 15 Feb 2017 22:41:41 +0000 | Subject | [PATCH 3.16 305/306] net: avoid signed overflows for SO_{SND|RCV}BUFFORCE |
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3.16.40-rc1 review patch. If anyone has any objections, please let me know.
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From: Eric Dumazet <edumazet@google.com>
commit b98b0bc8c431e3ceb4b26b0dfc8db509518fb290 upstream.
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: Ben Hutchings <ben@decadent.org.uk> --- net/core/sock.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
--- a/net/core/sock.c +++ b/net/core/sock.c @@ -749,7 +749,7 @@ int sock_setsockopt(struct socket *sock, 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; @@ -785,7 +785,7 @@ 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:
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