tcp: fix potential huge kmalloc() calls in TCP_REPAIR (5d4c9bfb) · Commits · 戴 / test

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: ("tcp: Move rcvq sending to tcp_input.c") Fixes: ("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>

net/ipv4/tcp_input.c

+19 −3

Original line number	Diff line number	Diff line
		@@ -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)

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