dccp/tcp: Avoid negative sk_forward_alloc by ipv6_pinfo.pktoptions.

commit ca43ccf41224b023fc290073d5603a755fd12eed upstream.

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: 323fbd0edf ("net: dccp: Add handling of IPV6_PKTOPTIONS to dccp_v6_do_rcv()")
Fixes: 3df80d9320 ("[DCCP]: Introduce DCCPv6")
Fixes: 1da177e4c3 ("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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Kuniyuki Iwashima
2023-02-09 16:22:01 -08:00
committed by Greg Kroah-Hartman
parent eb8e9d8572
commit 9d68bfa220
3 changed files with 18 additions and 12 deletions

View File

@@ -2243,6 +2243,19 @@ static inline __must_check bool skb_set_owner_sk_safe(struct sk_buff *skb, struc
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;
}
void sk_reset_timer(struct sock *sk, struct timer_list *timer,
unsigned long expires);