xfrm Fix use after free in __xfrm6_udp_encap_rcv.

A recent patch changed xfrm6_udp_encap_rcv to not
free the skb itself anymore but fogot the case
where xfrm4_udp_encap_rcv is called subsequently.

Fix this by moving the call to xfrm4_udp_encap_rcv
from __xfrm6_udp_encap_rcv to xfrm6_udp_encap_rcv.

Fixes: 221ddb723d90 ("xfrm: Support GRO for IPv6 ESP in UDP encapsulation")
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

diff --git a/net/ipv4/xfrm4_input.c b/net/ipv4/xfrm4_input.c
index 42879c5e026aeb39db877ed1c7ff6729a3c05462..c54676998eb60b7a47ee9defe8d97aec643dd1e1 100644 (file)
--- a/net/ipv4/xfrm4_input.c
+++ b/net/ipv4/xfrm4_input.c
@@ -159,7 +159,6 @@ static int __xfrm4_udp_encap_rcv(struct sock *sk, struct sk_buff *skb, bool pull
        /* process ESP */
        return 0;
 }
-EXPORT_SYMBOL(xfrm4_udp_encap_rcv);
 
 /* If it's a keepalive packet, then just eat it.
  * If it's an encapsulated packet, then pass it to the
@@ -184,6 +183,7 @@ int xfrm4_udp_encap_rcv(struct sock *sk, struct sk_buff *skb)
 
        return ret;
 }
+EXPORT_SYMBOL(xfrm4_udp_encap_rcv);
 
 struct sk_buff *xfrm4_gro_udp_encap_rcv(struct sock *sk, struct list_head *head,
                                        struct sk_buff *skb)
@@ -223,6 +223,7 @@ out:
 
        return NULL;
 }
+EXPORT_SYMBOL(xfrm4_gro_udp_encap_rcv);
 
 int xfrm4_rcv(struct sk_buff *skb)
 {

diff --git a/net/ipv6/xfrm6_input.c b/net/ipv6/xfrm6_input.c
index ccf79b84c0618f64a7d205388515466f204a149f..6e36e5047fbab6bd2a4236006bab5efa546d6850 100644 (file)
--- a/net/ipv6/xfrm6_input.c
+++ b/net/ipv6/xfrm6_input.c
@@ -80,9 +80,6 @@ static int __xfrm6_udp_encap_rcv(struct sock *sk, struct sk_buff *skb, bool pull
        __be32 *udpdata32;
        u16 encap_type;
 
-       if (skb->protocol == htons(ETH_P_IP))
-               return xfrm4_udp_encap_rcv(sk, skb);
-
        encap_type = READ_ONCE(up->encap_type);
        /* if this is not encapsulated socket, then just return now */
        if (!encap_type)
@@ -169,6 +166,9 @@ int xfrm6_udp_encap_rcv(struct sock *sk, struct sk_buff *skb)
 {
        int ret;
 
+       if (skb->protocol == htons(ETH_P_IP))
+               return xfrm4_udp_encap_rcv(sk, skb);
+
        ret = __xfrm6_udp_encap_rcv(sk, skb, true);
        if (!ret)
                return xfrm6_rcv_encap(skb, IPPROTO_ESP, 0,
@@ -190,6 +190,9 @@ struct sk_buff *xfrm6_gro_udp_encap_rcv(struct sock *sk, struct list_head *head,
        struct sk_buff *pp = NULL;
        int ret;
 
+       if (skb->protocol == htons(ETH_P_IP))
+               return xfrm4_gro_udp_encap_rcv(sk, head, skb);
+
        offset = offset - sizeof(struct udphdr);
 
        if (!pskb_pull(skb, offset))