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Commit 581e7226 authored Jan 24, 2018 by Tom Herbert Committed by David S. Miller Jan 24, 2018

kcm: Only allow TCP sockets to be attached to a KCM mux



TCP sockets for IPv4 and IPv6 that are not listeners or in closed
stated are allowed to be attached to a KCM mux.

Fixes: ab7ac4eb ("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>

parent d3303a65

net/kcm/kcmsock.c

+7 −2

Original line number	Diff line number	Diff line
		@@ -1387,8 +1387,13 @@ static int kcm_attach(struct socket sock, struct socket csock,
		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);