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bridge: netfilter stp fix reference to uninitialized data

PATCH Applied Stephen Hemminger 2 participants 2 messages Apr 27, 2018 – May 8, 2018

Subsystems (4)
Networking Network drivers netfilter Ethernet bridge
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Stephen Hemminger

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#0 lore raw

PATCH 1/1 bridge: netfilter stp fix reference to uninitialized data

The destination mac (destmac) is only valid if EBT_DESTMAC flag is set. Fix by changing the order of the comparison to look for the flag first.

Reported-by [email protected]
Signed-off-by Stephen Hemminger <[email protected]>

---
Note: no fixes since this bug goes back to pre-git days. Should go to stable as well.

 net/bridge/netfilter/ebt_stp.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
net/bridge/netfilter/ebt_stp.c +2 -2
index 47ba98db145d..46c1fe7637ea 100644
@@ -161,8 +161,8 @@ static int ebt_stp_mt_check(const struct xt_mtchk_param *par)
 	/* Make sure the match only receives stp frames */
 	if (!par->nft_compat &&
 	    (!ether_addr_equal(e->destmac, eth_stp_addr) ||
-	     !is_broadcast_ether_addr(e->destmsk) ||
-	     !(e->bitmask & EBT_DESTMAC)))
+	     !(e->bitmask & EBT_DESTMAC) ||
+	     !is_broadcast_ether_addr(e->destmsk)))
 		return -EINVAL;
 
 	return 0;
Signature · 1 line
2.17.0
maintainer Applied
#1 lore raw
Quoted 3 lines · Stephen Hemminger

The destination mac (destmac) is only valid if EBT_DESTMAC flag is set. Fix by changing the order of the comparison to look for the flag first.

Applied, thanks Stephen.