From: Arnd Bergmann <arnd@arndb.de>
To: "David S. Miller" <davem@davemloft.net>
Cc: Arnd Bergmann <arnd@arndb.de>,
Alexander Duyck <aduyck@mirantis.com>,
Tom Herbert <tom@herbertland.com>, Jiri Pirko <jiri@mellanox.com>,
Hadar Hen Zion <hadarh@mellanox.com>,
Gao Feng <fgao@48lvckh6395k16k5.yundunddos.com>,
Eric Garver <e@erig.me>, Amir Vadai <amir@vadai.me>,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH] flow_dissector: avoid uninitialized variable access
Date: Fri, 21 Oct 2016 17:55:53 +0200 [thread overview]
Message-ID: <20161021155626.4020344-1-arnd@arndb.de> (raw)
gcc warns about an uninitialized pointer dereference in the vlan
priority handling:
net/core/flow_dissector.c: In function '__skb_flow_dissect':
net/core/flow_dissector.c:281:61: error: 'vlan' may be used uninitialized in this function [-Werror=maybe-uninitialized]
>From all I can tell, this warning is about a real bug, and we
should not attempt look up the vlan header if there was
no vlan tag.
Fixes: f6a66927692e ("flow_dissector: Get vlan priority in addition to vlan id")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
I'm not sure about this one, please have a closer look at what
the original code does before applying.
---
net/core/flow_dissector.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c
index 44e6ba9d3a6b..dd6003bf27e1 100644
--- a/net/core/flow_dissector.c
+++ b/net/core/flow_dissector.c
@@ -245,7 +245,7 @@ bool __skb_flow_dissect(const struct sk_buff *skb,
}
case htons(ETH_P_8021AD):
case htons(ETH_P_8021Q): {
- const struct vlan_hdr *vlan;
+ const struct vlan_hdr *vlan = NULL;
if (skb && skb_vlan_tag_present(skb))
proto = skb->protocol;
@@ -264,7 +264,7 @@ bool __skb_flow_dissect(const struct sk_buff *skb,
}
skip_vlan = true;
- if (dissector_uses_key(flow_dissector,
+ if (vlan && dissector_uses_key(flow_dissector,
FLOW_DISSECTOR_KEY_VLAN)) {
key_vlan = skb_flow_dissector_target(flow_dissector,
FLOW_DISSECTOR_KEY_VLAN,
--
2.9.0
next reply other threads:[~2016-10-21 15:57 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-10-21 15:55 Arnd Bergmann [this message]
2016-10-21 16:31 ` [PATCH] flow_dissector: avoid uninitialized variable access Jiri Pirko
2016-10-21 21:05 ` Arnd Bergmann
2016-10-21 22:16 ` Arnd Bergmann
2016-10-22 15:57 ` Eric Garver
2016-10-22 18:20 ` Tom Herbert
2016-10-22 20:30 ` [PATCH net-next] flow_dissector: fix vlan tag handling Arnd Bergmann
2016-10-24 8:17 ` Jiri Pirko
2016-10-24 16:00 ` Arnd Bergmann
2016-10-22 1:48 ` [PATCH] flow_dissector: avoid uninitialized variable access Linus Torvalds
2016-10-22 6:55 ` Jiri Pirko
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