4.14-stable review patch. If anyone has any objections, please let me know.
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From: Tom Herbert tom@quantonium.net
commit 581e7226a5d43f629eb6399a121f85f6a15f81be upstream.
TCP sockets for IPv4 and IPv6 that are not listeners or in closed stated are allowed to be attached to a KCM mux.
Fixes: ab7ac4eb9832 ("kcm: Kernel Connection Multiplexor module") Reported-by: syzbot+8865eaff7f9acd593945@syzkaller.appspotmail.com Signed-off-by: Tom Herbert tom@quantonium.net Reviewed-by: Eric Dumazet edumazet@google.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- net/kcm/kcmsock.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-)
--- a/net/kcm/kcmsock.c +++ b/net/kcm/kcmsock.c @@ -1387,8 +1387,13 @@ static int kcm_attach(struct socket *soc if (!csk) return -EINVAL;
- /* We must prevent loops or risk deadlock ! */ - if (csk->sk_family == PF_KCM) + /* Only allow TCP sockets to be attached for now */ + if ((csk->sk_family != AF_INET && csk->sk_family != AF_INET6) || + csk->sk_protocol != IPPROTO_TCP) + return -EOPNOTSUPP; + + /* Don't allow listeners or closed sockets */ + if (csk->sk_state == TCP_LISTEN || csk->sk_state == TCP_CLOSE) return -EOPNOTSUPP;
psock = kmem_cache_zalloc(kcm_psockp, GFP_KERNEL);