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Commit 54d27fcb authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

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: default avatarMatt Schnall <mischnal@google.com>
Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Cc: Bernhard Beck <bbeck@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent efee8e87

net/ipv4/tcp.c

+5 −2
Original line number Original line 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) {

	for (i = 0; i < shi->nr_frags; ++i) {

		const struct skb_frag_struct *f = &shi->frags[i];

		const struct skb_frag_struct *f = &shi->frags[i];

		struct page *page = skb_frag_page(f);

		unsigned int offset = f->page_offset;

		sg_set_page(&sg, page, skb_frag_size(f), 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)))

		if (crypto_hash_update(desc, &sg, skb_frag_size(f)))

			return 1;

			return 1;

	}

	}