From 3acd879fb272b36a8137aae0b591221fed3837a0 Mon Sep 17 00:00:00 2001
From: Tom Herbert <tom@quantonium.net>
Date: Wed, 24 Jan 2018 12:35:40 -0800
Subject: [PATCH] kcm: Only allow TCP sockets to be attached to a KCM mux
Git-commit: 581e7226a5d43f629eb6399a121f85f6a15f81be
Patch-mainline: v4.15
References: git-fixes
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: Denis Kirjanov <denis.kirjanov@suse.com>
---
net/kcm/kcmsock.c | 13 ++++++++-----
1 file changed, 8 insertions(+), 5 deletions(-)
diff --git a/net/kcm/kcmsock.c b/net/kcm/kcmsock.c
index 473ad3ebdff2..c6e325199495 100644
--- 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);
--
2.16.4