Commit 54d27fcb authored May 13, 2013 by Eric Dumazet Committed by David S. Miller May 14, 2013

tcp: fix tcp_md5_hash_skb_data()



TCP md5 communications fail [1] for some devices, because sg/crypto code
assume page offsets are below PAGE_SIZE.

This was discovered using mlx4 driver [2], but I suspect loopback
might trigger the same bug now we use order-3 pages in tcp_sendmsg()

[1] Failure is giving following messages.

huh, entered softirq 3 NET_RX ffffffff806ad230 preempt_count 00000100,
exited with 00000101?

[2] mlx4 driver uses order-2 pages to allocate RX frags

Reported-by: Matt Schnall <mischnal@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Bernhard Beck <bbeck@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent efee8e87

net/ipv4/tcp.c

+5 −2

Original line number	Diff line number	Diff line
		@@ -3269,8 +3269,11 @@ int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *hp,

		for (i = 0; i < shi->nr_frags; ++i) {
		const struct skb_frag_struct *f = &shi->frags[i];
		struct page *page = skb_frag_page(f);
		sg_set_page(&sg, page, skb_frag_size(f), f->page_offset);
		unsigned int offset = f->page_offset;
		struct page *page = skb_frag_page(f) + (offset >> PAGE_SHIFT);

		sg_set_page(&sg, page, skb_frag_size(f),
		offset_in_page(offset));
		if (crypto_hash_update(desc, &sg, skb_frag_size(f)))
		return 1;
		}

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