[ 44/95] tcp: fix tcp_md5_hash_skb_data()
From: Greg Kroah-Hartman
Date: Tue Jun 25 2013 - 15:04:44 EST
3.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Eric Dumazet <edumazet@xxxxxxxxxx>
[ Upstream commit 54d27fcb338bd9c42d1dfc5a39e18f6f9d373c2e ]
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@xxxxxxxxxx>
Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Cc: Bernhard Beck <bbeck@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/ipv4/tcp.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -3383,8 +3383,11 @@ int tcp_md5_hash_skb_data(struct tcp_md5
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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