[PATCH 4.9 003/145] kcm: Only allow TCP sockets to be attached to a KCM mux

[Greg Kroah-Hartman]

4.9-stable review patch.  If anyone has any objections, please let me know.

--

From: Tom Herbert 

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+8865eaff7f9acd593...@syzkaller.appspotmail.com
Signed-off-by: Tom Herbert 
Reviewed-by: Eric Dumazet 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman 

---
 net/kcm/kcmsock.c |9 +++--
 1 file changed, 7 insertions(+), 2 deletions(-)

--- a/net/kcm/kcmsock.c
+++ b/net/kcm/kcmsock.c
@@ -1381,8 +1381,13 @@ 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);

[PATCH 4.9 003/145] kcm: Only allow TCP sockets to be attached to a KCM mux

[Greg Kroah-Hartman]

4.9-stable review patch.  If anyone has any objections, please let me know.

--

From: Tom Herbert 

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+8865eaff7f9acd593...@syzkaller.appspotmail.com
Signed-off-by: Tom Herbert 
Reviewed-by: Eric Dumazet 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman 

---
 net/kcm/kcmsock.c |9 +++--
 1 file changed, 7 insertions(+), 2 deletions(-)

--- a/net/kcm/kcmsock.c
+++ b/net/kcm/kcmsock.c
@@ -1381,8 +1381,13 @@ 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);