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| author | Eric Dumazet <edumazet@google.com> | 2021-04-13 05:41:35 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-08-04 12:22:15 +0200 |
| commit | b2ac545efdb8ad273df23be34aa6644067ecd3b6 (patch) | |
| tree | 7658dc45f14322dcc64f7593123a4c0bd970f94e | |
| parent | 2789bc090f4a2caef0cceb3f108867de608bb23a (diff) | |
| download | linux-stable-b2ac545efdb8ad273df23be34aa6644067ecd3b6.tar.gz linux-stable-b2ac545efdb8ad273df23be34aa6644067ecd3b6.tar.bz2 linux-stable-b2ac545efdb8ad273df23be34aa6644067ecd3b6.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: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | include/linux/skbuff.h | 9 | ||||
| -rw-r--r-- | net/core/dev.c | 3 |
2 files changed, 11 insertions, 1 deletions
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index de3e59329b02..2f303454a323 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -2785,6 +2785,15 @@ static inline void skb_propagate_pfmemalloc(struct page *page, } /** + * skb_frag_off() - Returns the offset of a skb fragment + * @frag: the paged fragment + */ +static inline unsigned int skb_frag_off(const skb_frag_t *frag) +{ + return frag->page_offset; +} + +/** * skb_frag_page - retrieve the page referred to by a paged fragment * @frag: the paged fragment * diff --git a/net/core/dev.c b/net/core/dev.c index aa419f3162b8..ea09e0809c12 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -4763,7 +4763,8 @@ 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), |