diff options
author | Shmulik Ladkani <shmulik.ladkani@ravellosystems.com> | 2016-09-20 12:48:36 +0300 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-05-10 10:26:35 +0200 |
commit | 5601a885975551f9d3650bcafab9610a55c768a7 (patch) | |
tree | 0981e7b0a6dd7b31d47f7761a0e42195967566d1 /net/core/skbuff.c | |
parent | fff70051a18e96d2e758ef261b3b19c9e33c8d28 (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.c | 10 |
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; |