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| author | Eric Dumazet <edumazet@google.com> | 2015-11-18 21:03:33 -0800 |
|---|---|---|
| committer | Sasha Levin <sasha.levin@oracle.com> | 2015-12-14 12:19:24 -0500 |
| commit | ea5ef9fc2c94fd0156d4671f2327d14f830ec80b (patch) | |
| tree | 21d3d69bae8fb065a0206ed4e69f331c8c71fd88 | |
| parent | 7af8323046e487cf0f9f0e9d202cf8f78b0225af (diff) | |
| download | lwn-ea5ef9fc2c94fd0156d4671f2327d14f830ec80b.tar.gz lwn-ea5ef9fc2c94fd0156d4671f2327d14f830ec80b.zip | |
tcp: fix potential huge kmalloc() calls in TCP_REPAIR
[ Upstream commit 5d4c9bfbabdb1d497f21afd81501e5c54b0c85d9 ]
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: 292e8d8c8538 ("tcp: Move rcvq sending to tcp_input.c")
Fixes: c0e88ff0f256 ("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>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
| -rw-r--r-- | net/ipv4/tcp_input.c | 22 |
1 files changed, 19 insertions, 3 deletions
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index 6f46cde58e54..aa167155b686 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -4356,19 +4356,34 @@ 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_fromiovec(skb_put(skb, size), msg->msg_iov, size)) + err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, size); + if (err) goto err_free; TCP_SKB_CB(skb)->seq = tcp_sk(sk)->rcv_nxt; @@ -4384,7 +4399,8 @@ 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) |