Eric Dumazet pointed out [0] that when we call skb_set_owner_r()
for ipv6_pinfo.pktoptions, sk_rmem_schedule() has not been called,
resulting in a negative sk_forward_alloc.
We add a new helper which clones a skb and sets its owner only
when sk_rmem_schedule() succeeds.
Note that we move skb_set_owner_r() forward in (dccp|tcp)_v6_do_rcv()
because tcp_send_synack() can make sk_forward_alloc negative before
ipv6_opt_accepted() in the crossed SYN-ACK or self-connect() cases.
[0]: https://lore.kernel.org/netdev/CANn89iK9oc20Jdi_41jb9URdF210r7d1Y-+uypbMSbOfY6jqrg@mail.gmail.com/
Fixes:
323fbd0edf3f ("net: dccp: Add handling of IPV6_PKTOPTIONS to dccp_v6_do_rcv()")
Fixes:
3df80d9320bc ("[DCCP]: Introduce DCCPv6")
Fixes:
1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
return false;
}
+static inline struct sk_buff *skb_clone_and_charge_r(struct sk_buff *skb, struct sock *sk)
+{
+ skb = skb_clone(skb, sk_gfp_mask(sk, GFP_ATOMIC));
+ if (skb) {
+ if (sk_rmem_schedule(sk, skb, skb->truesize)) {
+ skb_set_owner_r(skb, sk);
+ return skb;
+ }
+ __kfree_skb(skb);
+ }
+ return NULL;
+}
+
static inline void skb_prepare_for_gro(struct sk_buff *skb)
{
if (skb->destructor != sock_wfree) {
*own_req = inet_ehash_nolisten(newsk, req_to_sk(req_unhash), NULL);
/* Clone pktoptions received with SYN, if we own the req */
if (*own_req && ireq->pktopts) {
- newnp->pktoptions = skb_clone(ireq->pktopts, GFP_ATOMIC);
+ newnp->pktoptions = skb_clone_and_charge_r(ireq->pktopts, newsk);
consume_skb(ireq->pktopts);
ireq->pktopts = NULL;
- if (newnp->pktoptions)
- skb_set_owner_r(newnp->pktoptions, newsk);
}
return newsk;
--ANK (980728)
*/
if (np->rxopt.all)
- opt_skb = skb_clone(skb, GFP_ATOMIC);
+ opt_skb = skb_clone_and_charge_r(skb, sk);
if (sk->sk_state == DCCP_OPEN) { /* Fast path */
if (dccp_rcv_established(sk, skb, dccp_hdr(skb), skb->len))
np->flow_label = ip6_flowlabel(ipv6_hdr(opt_skb));
if (ipv6_opt_accepted(sk, opt_skb,
&DCCP_SKB_CB(opt_skb)->header.h6)) {
- skb_set_owner_r(opt_skb, sk);
memmove(IP6CB(opt_skb),
&DCCP_SKB_CB(opt_skb)->header.h6,
sizeof(struct inet6_skb_parm));
/* Clone pktoptions received with SYN, if we own the req */
if (ireq->pktopts) {
- newnp->pktoptions = skb_clone(ireq->pktopts,
- sk_gfp_mask(sk, GFP_ATOMIC));
+ newnp->pktoptions = skb_clone_and_charge_r(ireq->pktopts, newsk);
consume_skb(ireq->pktopts);
ireq->pktopts = NULL;
- if (newnp->pktoptions) {
+ if (newnp->pktoptions)
tcp_v6_restore_cb(newnp->pktoptions);
- skb_set_owner_r(newnp->pktoptions, newsk);
- }
}
} else {
if (!req_unhash && found_dup_sk) {
--ANK (980728)
*/
if (np->rxopt.all)
- opt_skb = skb_clone(skb, sk_gfp_mask(sk, GFP_ATOMIC));
+ opt_skb = skb_clone_and_charge_r(skb, sk);
reason = SKB_DROP_REASON_NOT_SPECIFIED;
if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
if (np->repflow)
np->flow_label = ip6_flowlabel(ipv6_hdr(opt_skb));
if (ipv6_opt_accepted(sk, opt_skb, &TCP_SKB_CB(opt_skb)->header.h6)) {
- skb_set_owner_r(opt_skb, sk);
tcp_v6_restore_cb(opt_skb);
opt_skb = xchg(&np->pktoptions, opt_skb);
} else {