[AF_PACKET]: Fix BPF handling.

[firefly-linux-kernel-4.4.55.git] / net / packet / af_packet.c

diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index da73e8a8c18de58377376237907b32cf3baee35e..594c078c5ebc3b2093d5ec77ffb68805979618ec 100644 (file)
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -428,24 +428,18 @@ out_unlock:
 }
 #endif
 
-static inline int run_filter(struct sk_buff *skb, struct sock *sk,
-                                                       unsigned *snaplen)
+static inline unsigned int run_filter(struct sk_buff *skb, struct sock *sk,
+                                     unsigned int res)
 {
        struct sk_filter *filter;
-       int err = 0;
 
        rcu_read_lock_bh();
        filter = rcu_dereference(sk->sk_filter);
-       if (filter != NULL) {
-               err = sk_run_filter(skb, filter->insns, filter->len);
-               if (!err)
-                       err = -EPERM;
-               else if (*snaplen > err)
-                       *snaplen = err;
-       }
+       if (filter != NULL)
+               res = sk_run_filter(skb, filter->insns, filter->len);
        rcu_read_unlock_bh();
 
-       return err;
+       return res;
 }
 
 /*
@@ -467,7 +461,7 @@ static int packet_rcv(struct sk_buff *skb, struct net_device *dev, struct packet
        struct packet_sock *po;
        u8 * skb_head = skb->data;
        int skb_len = skb->len;
-       unsigned snaplen;
+       unsigned int snaplen, res;
 
        if (skb->pkt_type == PACKET_LOOPBACK)
                goto drop;
@@ -495,8 +489,11 @@ static int packet_rcv(struct sk_buff *skb, struct net_device *dev, struct packet
 
        snaplen = skb->len;
 
-       if (run_filter(skb, sk, &snaplen) < 0)
+       res = run_filter(skb, sk, snaplen);
+       if (!res)
                goto drop_n_restore;
+       if (snaplen > res)
+               snaplen = res;
 
        if (atomic_read(&sk->sk_rmem_alloc) + skb->truesize >=
            (unsigned)sk->sk_rcvbuf)
@@ -568,7 +565,7 @@ static int tpacket_rcv(struct sk_buff *skb, struct net_device *dev, struct packe
        struct tpacket_hdr *h;
        u8 * skb_head = skb->data;
        int skb_len = skb->len;
-       unsigned snaplen;
+       unsigned int snaplen, res;
        unsigned long status = TP_STATUS_LOSING|TP_STATUS_USER;
        unsigned short macoff, netoff;
        struct sk_buff *copy_skb = NULL;
@@ -592,8 +589,11 @@ static int tpacket_rcv(struct sk_buff *skb, struct net_device *dev, struct packe
 
        snaplen = skb->len;
 
-       if (run_filter(skb, sk, &snaplen) < 0)
+       res = run_filter(skb, sk, snaplen);
+       if (!res)
                goto drop_n_restore;
+       if (snaplen > res)
+               snaplen = res;
 
        if (sk->sk_type == SOCK_DGRAM) {
                macoff = netoff = TPACKET_ALIGN(TPACKET_HDRLEN) + 16;