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authorShmulik Ladkani <shmulik.ladkani@ravellosystems.com>2016-09-20 12:48:36 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2020-05-10 10:26:35 +0200
commit5601a885975551f9d3650bcafab9610a55c768a7 (patch)
tree0981e7b0a6dd7b31d47f7761a0e42195967566d1 /net/core/skbuff.c
parentfff70051a18e96d2e758ef261b3b19c9e33c8d28 (diff)
net: skbuff: Remove errornous length validation in skb_vlan_pop()
commit 636c2628086e40c86dac7ddc84a1c4b4fcccc6e3 upstream. In 93515d53b1 "net: move vlan pop/push functions into common code" skb_vlan_pop was moved from its private location in openvswitch to skbuff common code. In case skb has non hw-accel vlan tag, the original 'pop_vlan()' assured that skb->len is sufficient (if skb->len < VLAN_ETH_HLEN then pop was considered a no-op). This validation was moved as is into the new common 'skb_vlan_pop'. Alas, in its original location (openvswitch), there was a guarantee that 'data' points to the mac_header, therefore the 'skb->len < VLAN_ETH_HLEN' condition made sense. However there's no such guarantee in the generic 'skb_vlan_pop'. For short packets received in rx path going through 'skb_vlan_pop', this causes 'skb_vlan_pop' to fail pop-ing a valid vlan hdr (in the non hw-accel case) or to fail moving next tag into hw-accel tag. Remove the 'skb->len < VLAN_ETH_HLEN' condition entirely: It is superfluous since inner '__skb_vlan_pop' already verifies there are VLAN_ETH_HLEN writable bytes at the mac_header. Note this presents a slight change to skb_vlan_pop() users: In case total length is smaller than VLAN_ETH_HLEN, skb_vlan_pop() now returns an error, as opposed to previous "no-op" behavior. Existing callers (e.g. tc act vlan, ovs) usually drop the packet if 'skb_vlan_pop' fails. Fixes: 93515d53b1 ("net: move vlan pop/push functions into common code") Signed-off-by: Shmulik Ladkani <shmulik.ladkani@gmail.com> Cc: Pravin Shelar <pshelar@ovn.org> Reviewed-by: Pravin B Shelar <pshelar@ovn.org> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'net/core/skbuff.c')
-rw-r--r--net/core/skbuff.c10
1 files changed, 4 insertions, 6 deletions
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 2f63a90065e6..4e944fe98627 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -4451,9 +4451,8 @@ int skb_vlan_pop(struct sk_buff *skb)
if (likely(skb_vlan_tag_present(skb))) {
skb->vlan_tci = 0;
} else {
- if (unlikely((skb->protocol != htons(ETH_P_8021Q) &&
- skb->protocol != htons(ETH_P_8021AD)) ||
- skb->len < VLAN_ETH_HLEN))
+ if (unlikely(skb->protocol != htons(ETH_P_8021Q) &&
+ skb->protocol != htons(ETH_P_8021AD)))
return 0;
err = __skb_vlan_pop(skb, &vlan_tci);
@@ -4461,9 +4460,8 @@ int skb_vlan_pop(struct sk_buff *skb)
return err;
}
/* move next vlan tag to hw accel tag */
- if (likely((skb->protocol != htons(ETH_P_8021Q) &&
- skb->protocol != htons(ETH_P_8021AD)) ||
- skb->len < VLAN_ETH_HLEN))
+ if (likely(skb->protocol != htons(ETH_P_8021Q) &&
+ skb->protocol != htons(ETH_P_8021AD)))
return 0;
vlan_proto = skb->protocol;