diff options
| author | Eric Dumazet <[email protected]> | 2021-04-13 05:41:35 -0700 |
|---|---|---|
| committer | David S. Miller <[email protected]> | 2021-04-13 15:09:31 -0700 |
| commit | 38ec4944b593fd90c5ef42aaaa53e66ae5769d04 (patch) | |
| tree | ada126e3929b87d7b29b858478f5b8f5bf70475c | |
| parent | b166a20b07382b8bc1dcee2a448715c9c2c81b5b (diff) | |
gro: ensure frag0 meets IP header alignment
After commit 0f6925b3e8da ("virtio_net: Do not pull payload in skb->head")
Guenter Roeck reported one failure in his tests using sh architecture.
After much debugging, we have been able to spot silent unaligned accesses
in inet_gro_receive()
The issue at hand is that upper networking stacks assume their header
is word-aligned. Low level drivers are supposed to reserve NET_IP_ALIGN
bytes before the Ethernet header to make that happen.
This patch hardens skb_gro_reset_offset() to not allow frag0 fast-path
if the fragment is not properly aligned.
Some arches like x86, arm64 and powerpc do not care and define NET_IP_ALIGN
as 0, this extra check will be a NOP for them.
Note that if frag0 is not used, GRO will call pskb_may_pull()
as many times as needed to pull network and transport headers.
Fixes: 0f6925b3e8da ("virtio_net: Do not pull payload in skb->head")
Fixes: 78a478d0efd9 ("gro: Inline skb_gro_header and cache frag0 virtual address")
Signed-off-by: Eric Dumazet <[email protected]>
Reported-by: Guenter Roeck <[email protected]>
Cc: Xuan Zhuo <[email protected]>
Cc: "Michael S. Tsirkin" <[email protected]>
Cc: Jason Wang <[email protected]>
Acked-by: Michael S. Tsirkin <[email protected]>
Tested-by: Guenter Roeck <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
| -rw-r--r-- | net/core/dev.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/net/core/dev.c b/net/core/dev.c index af8c1ea040b9..1f79b9aa9a3f 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -5924,7 +5924,8 @@ static void skb_gro_reset_offset(struct sk_buff *skb) NAPI_GRO_CB(skb)->frag0_len = 0; if (!skb_headlen(skb) && pinfo->nr_frags && - !PageHighMem(skb_frag_page(frag0))) { + !PageHighMem(skb_frag_page(frag0)) && + (!NET_IP_ALIGN || !(skb_frag_off(frag0) & 3))) { NAPI_GRO_CB(skb)->frag0 = skb_frag_address(frag0); NAPI_GRO_CB(skb)->frag0_len = min_t(unsigned int, skb_frag_size(frag0), |