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| author | Eric Dumazet <edumazet@google.com> | 2021-04-13 05:41:35 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-04-21 12:56:17 +0200 |
| commit | 9a7ac9afc8d77e3bd99583164fa3bc8b9e6b4a48 (patch) | |
| tree | a709d22cbd2bbfddc4c7dc972970b2e410c95c4f | |
| parent | fde195c03bff160b90e6a21c2fd7159b685846a9 (diff) | |
| download | linux-9a7ac9afc8d77e3bd99583164fa3bc8b9e6b4a48.tar.gz linux-9a7ac9afc8d77e3bd99583164fa3bc8b9e6b4a48.tar.bz2 linux-9a7ac9afc8d77e3bd99583164fa3bc8b9e6b4a48.zip | |
gro: ensure frag0 meets IP header alignment
commit 38ec4944b593fd90c5ef42aaaa53e66ae5769d04 upstream.
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 <edumazet@google.com>
Reported-by: Guenter Roeck <linux@roeck-us.net>
Cc: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -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 2ec21380f86d..91909e5d6807 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -5406,7 +5406,8 @@ static void skb_gro_reset_offset(struct sk_buff *skb) if (skb_mac_header(skb) == skb_tail_pointer(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), |