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tcp: fix potential huge kmalloc() calls in TCP_REPAIR

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tcp_send_rcvq() is used for re-injecting data into tcp receive queue.

Problems :

- No check against size is performed, allowed user to fool kernel in
  attempting very large memory allocations, eventually triggering
  OOM when memory is fragmented.

- In case of fault during the copy we do not return correct errno.

Lets use alloc_skb_with_frags() to cook optimal skbs.

Fixes: 292e8d8c85 ("tcp: Move rcvq sending to tcp_input.c")
Fixes: c0e88ff0f2 ("tcp: Repair socket queues")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Pavel Emelyanov <xemul@parallels.com>
Acked-by: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet 2015-11-18 21:03:33 -08:00 committed by David S. Miller
parent dd52bc2b4e
commit 5d4c9bfbab
1 changed files with 19 additions and 3 deletions
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22
net/ipv4/tcp_input.c
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@ -4481,19 +4481,34 @@ static int __must_check tcp_queue_rcv(struct sock *sk, struct sk_buff *skb, int
int tcp_send_rcvq(struct sock *sk, struct msghdr *msg, size_t size)
{
struct sk_buff *skb;
int err = -ENOMEM;
int data_len = 0;
bool fragstolen;
if (size == 0)
return 0;
skb = alloc_skb(size, sk->sk_allocation);
if (size > PAGE_SIZE) {
int npages = min_t(size_t, size >> PAGE_SHIFT, MAX_SKB_FRAGS);
data_len = npages << PAGE_SHIFT;
size = data_len + (size & ~PAGE_MASK);
}
skb = alloc_skb_with_frags(size - data_len, data_len,
PAGE_ALLOC_COSTLY_ORDER,
&err, sk->sk_allocation);
if (!skb)
goto err;
skb_put(skb, size - data_len);
skb->data_len = data_len;
skb->len = size;
if (tcp_try_rmem_schedule(sk, skb, skb->truesize))
goto err_free;
if (memcpy_from_msg(skb_put(skb, size), msg, size))
err = skb_copy_datagram_from_iter(skb, 0, &msg->msg_iter, size);
if (err)
goto err_free;
TCP_SKB_CB(skb)->seq = tcp_sk(sk)->rcv_nxt;
@ -4509,7 +4524,8 @@ int tcp_send_rcvq(struct sock *sk, struct msghdr *msg, size_t size)
err_free:
kfree_skb(skb);
err:
return -ENOMEM;
return err;
}
static void tcp_data_queue(struct sock *sk, struct sk_buff *skb)