net: gro: fix a potential crash in skb_gro_reset_offset
Before accessing skb first fragment, better make sure there
is one.
This is probably not needed for old kernels, since an ethernet frame
cannot contain only an ethernet header, but the recent GRO addition
to tunnels makes this patch needed.
Also skb_gro_reset_offset() can be static, it actually allows
compiler to inline it.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/core/dev.c b/net/core/dev.c
index 1e0a184..de2bad7 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -3631,20 +3631,22 @@
}
EXPORT_SYMBOL(napi_skb_finish);
-void skb_gro_reset_offset(struct sk_buff *skb)
+static void skb_gro_reset_offset(struct sk_buff *skb)
{
+ const struct skb_shared_info *pinfo = skb_shinfo(skb);
+ const skb_frag_t *frag0 = &pinfo->frags[0];
+
NAPI_GRO_CB(skb)->data_offset = 0;
NAPI_GRO_CB(skb)->frag0 = NULL;
NAPI_GRO_CB(skb)->frag0_len = 0;
if (skb->mac_header == skb->tail &&
- !PageHighMem(skb_frag_page(&skb_shinfo(skb)->frags[0]))) {
- NAPI_GRO_CB(skb)->frag0 =
- skb_frag_address(&skb_shinfo(skb)->frags[0]);
- NAPI_GRO_CB(skb)->frag0_len = skb_frag_size(&skb_shinfo(skb)->frags[0]);
+ pinfo->nr_frags &&
+ !PageHighMem(skb_frag_page(frag0))) {
+ NAPI_GRO_CB(skb)->frag0 = skb_frag_address(frag0);
+ NAPI_GRO_CB(skb)->frag0_len = skb_frag_size(frag0);
}
}
-EXPORT_SYMBOL(skb_gro_reset_offset);
gro_result_t napi_gro_receive(struct napi_struct *napi, struct sk_buff *skb)
{