net: synack packets can be attached to request sockets

selinux needs few changes to accommodate fact that SYNACK messages
can be attached to a request socket, lacking sk_security pointer

(Only syncookies are still attached to a TCP_LISTEN socket)

Adds a new sk_listener() helper, and use it in selinux and sch_fq

Fixes: ca6fb0651883 ("tcp: attach SYNACK messages to request sockets instead of listener")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported by: kernel test robot <ying.huang@linux.intel.com>
Cc: Paul Moore <paul@paul-moore.com>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: Eric Paris <eparis@parisplace.org>
Acked-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/net/sock.h b/include/net/sock.h
index dfe2eb8..771ca19 100644 (file)
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -2201,6 +2201,14 @@ static inline bool sk_fullsock(const struct sock *sk)
        return (1 << sk->sk_state) & ~(TCPF_TIME_WAIT | TCPF_NEW_SYN_RECV);
 }
 
+/* This helper checks if a socket is a LISTEN or NEW_SYN_RECV
+ * SYNACK messages can be attached to either ones (depending on SYNCOOKIE)
+ */
+static inline bool sk_listener(const struct sock *sk)
+{
+       return (1 << sk->sk_state) & (TCPF_LISTEN | TCPF_NEW_SYN_RECV);
+}
+
 void sock_enable_timestamp(struct sock *sk, int flag);
 int sock_get_timestamp(struct sock *, struct timeval __user *);
 int sock_get_timestampns(struct sock *, struct timespec __user *);

diff --git a/net/sched/sch_fq.c b/net/sched/sch_fq.c
index 3386cce..109b232 100644 (file)
--- a/net/sched/sch_fq.c
+++ b/net/sched/sch_fq.c
@@ -225,6 +225,7 @@ static struct fq_flow *fq_classify(struct sk_buff *skb, struct fq_sched_data *q)
                return &q->internal;
 
        /* SYNACK messages are attached to a TCP_NEW_SYN_RECV request socket
+        * or a listener (SYNCOOKIE mode)
         * 1) request sockets are not full blown,
         *    they do not contain sk_pacing_rate
         * 2) They are not part of a 'flow' yet
@@ -232,7 +233,7 @@ static struct fq_flow *fq_classify(struct sk_buff *skb, struct fq_sched_data *q)
         *    especially if the listener set SO_MAX_PACING_RATE
         * 4) We pretend they are orphaned
         */
-       if (!sk || sk->sk_state == TCP_NEW_SYN_RECV) {
+       if (!sk || sk_listener(sk)) {
                unsigned long hash = skb_get_hash(skb) & q->orphan_mask;
 
                /* By forcing low order bit to 1, we make sure to not

diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 6434016..6e50841 100644 (file)
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -4898,7 +4898,7 @@ static unsigned int selinux_ip_output(struct sk_buff *skb,
        if (sk) {
                struct sk_security_struct *sksec;
 
-               if (sk->sk_state == TCP_LISTEN)
+               if (sk_listener(sk))
                        /* if the socket is the listening state then this
                         * packet is a SYN-ACK packet which means it needs to
                         * be labeled based on the connection/request_sock and
@@ -5005,7 +5005,7 @@ static unsigned int selinux_ip_postroute(struct sk_buff *skb,
         *       unfortunately, this means more work, but it is only once per
         *       connection. */
        if (skb_dst(skb) != NULL && skb_dst(skb)->xfrm != NULL &&
-           !(sk != NULL && sk->sk_state == TCP_LISTEN))
+           !(sk && sk_listener(sk)))
                return NF_ACCEPT;
 #endif
 
@@ -5022,7 +5022,7 @@ static unsigned int selinux_ip_postroute(struct sk_buff *skb,
                        secmark_perm = PACKET__SEND;
                        peer_sid = SECINITSID_KERNEL;
                }
-       } else if (sk->sk_state == TCP_LISTEN) {
+       } else if (sk_listener(sk)) {
                /* Locally generated packet but the associated socket is in the
                 * listening state which means this is a SYN-ACK packet.  In
                 * this particular case the correct security label is assigned
@@ -5033,7 +5033,11 @@ static unsigned int selinux_ip_postroute(struct sk_buff *skb,
                 * selinux_inet_conn_request().  See also selinux_ip_output()
                 * for similar problems. */
                u32 skb_sid;
-               struct sk_security_struct *sksec = sk->sk_security;
+               struct sk_security_struct *sksec;
+
+               if (sk->sk_state == TCP_NEW_SYN_RECV)
+                       sk = inet_reqsk(sk)->rsk_listener;
+               sksec = sk->sk_security;
                if (selinux_skb_peerlbl_sid(skb, family, &skb_sid))
                        return NF_DROP;
                /* At this point, if the returned skb peerlbl is SECSID_NULL