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authorCong Wang <xiyou.wangcong@gmail.com>2019-12-05 19:39:02 -0800
committerDavid S. Miller <davem@davemloft.net>2019-12-07 11:53:27 -0800
commit0e4940928c26527ce8f97237fef4c8a91cd34207 (patch)
tree7e7f865d29451d37511dd9171e61992fbad6f8d0
parentpppoe: remove redundant BUG_ON() check in pppoe_pernet (diff)
downloadlinux-dev-0e4940928c26527ce8f97237fef4c8a91cd34207.tar.xz
linux-dev-0e4940928c26527ce8f97237fef4c8a91cd34207.zip
gre: refetch erspan header from skb->data after pskb_may_pull()
After pskb_may_pull() we should always refetch the header pointers from the skb->data in case it got reallocated. In gre_parse_header(), the erspan header is still fetched from the 'options' pointer which is fetched before pskb_may_pull(). Found this during code review of a KMSAN bug report. Fixes: cb73ee40b1b3 ("net: ip_gre: use erspan key field for tunnel lookup") Cc: Lorenzo Bianconi <lorenzo.bianconi@redhat.com> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Acked-by: Lorenzo Bianconi <lorenzo.bianconi@redhat.com> Acked-by: William Tu <u9012063@gmail.com> Reviewed-by: Simon Horman <simon.horman@netronome.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--net/ipv4/gre_demux.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/net/ipv4/gre_demux.c b/net/ipv4/gre_demux.c
index 44bfeecac33e..5fd6e8ed02b5 100644
--- a/net/ipv4/gre_demux.c
+++ b/net/ipv4/gre_demux.c
@@ -127,7 +127,7 @@ int gre_parse_header(struct sk_buff *skb, struct tnl_ptk_info *tpi,
if (!pskb_may_pull(skb, nhs + hdr_len + sizeof(*ershdr)))
return -EINVAL;
- ershdr = (struct erspan_base_hdr *)options;
+ ershdr = (struct erspan_base_hdr *)(skb->data + nhs + hdr_len);
tpi->key = cpu_to_be32(get_session_id(ershdr));
}