gro: fix ownership transfer

commit ed4cccef64c1d0d5b91e69f7a8a6697c3a865486 upstream.

If packets are GROed with fraglist they might be segmented later on and
continue their journey in the stack. In skb_segment_list those skbs can
be reused as-is. This is an issue as their destructor was removed in
skb_gro_receive_list but not the reference to their socket, and then
they can't be orphaned. Fix this by also removing the reference to the
socket.

For example this could be observed,

  kernel BUG at include/linux/skbuff.h:3131!  (skb_orphan)
  RIP: 0010:ip6_rcv_core+0x11bc/0x19a0
  Call Trace:
   ipv6_list_rcv+0x250/0x3f0
   __netif_receive_skb_list_core+0x49d/0x8f0
   netif_receive_skb_list_internal+0x634/0xd40
   napi_complete_done+0x1d2/0x7d0
   gro_cell_poll+0x118/0x1f0

A similar construction is found in skb_gro_receive, apply the same
change there.

Fixes: 5e10da5385d2 ("skbuff: allow 'slow_gro' for skb carring sock reference")
Signed-off-by: Antoine Tenart <atenart@kernel.org>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/core/gro.c b/net/core/gro.c
index 0759277dc14ee65d0a5376d48694cc1cccaee959..cefddf65f7db0d92da8b8f4a1c40cb7be0f201ca 100644 (file)
--- a/net/core/gro.c
+++ b/net/core/gro.c
@@ -195,8 +195,9 @@ int skb_gro_receive(struct sk_buff *p, struct sk_buff *skb)
        }
 
 merge:
-       /* sk owenrship - if any - completely transferred to the aggregated packet */
+       /* sk ownership - if any - completely transferred to the aggregated packet */
        skb->destructor = NULL;
+       skb->sk = NULL;
        delta_truesize = skb->truesize;
        if (offset > headlen) {
                unsigned int eat = offset - headlen;

diff --git a/net/ipv4/udp_offload.c b/net/ipv4/udp_offload.c
index 6c95d28d0c4a7e56d587a986113b3711f8de964c..0064c9c1c6ead390e62629b9a706ae272ae04ebb 100644 (file)
--- a/net/ipv4/udp_offload.c
+++ b/net/ipv4/udp_offload.c
@@ -449,8 +449,9 @@ static int skb_gro_receive_list(struct sk_buff *p, struct sk_buff *skb)
        NAPI_GRO_CB(p)->count++;
        p->data_len += skb->len;
 
-       /* sk owenrship - if any - completely transferred to the aggregated packet */
+       /* sk ownership - if any - completely transferred to the aggregated packet */
        skb->destructor = NULL;
+       skb->sk = NULL;
        p->truesize += skb->truesize;
        p->len += skb->len;