* [patch net/stable] br: fix use of ->rx_handler_data in code executed on non-rx_handler path
@ 2013-12-05 14:50 Jiri Pirko
2013-12-05 14:58 ` Michael S. Tsirkin
2013-12-05 15:18 ` Eric Dumazet
0 siblings, 2 replies; 6+ messages in thread
From: Jiri Pirko @ 2013-12-05 14:50 UTC (permalink / raw)
To: netdev; +Cc: davem, jtluka, zhiguohong, bridge, stephen, edumazet, laine, mst
br_stp_rcv() is reached by non-rx_handler path. That means there is no
guarantee that dev is bridge port and therefore simple NULL check of
->rx_handler_data is not enough. There is need to check if dev is really
bridge port and since only rcu read lock is held here, do it by checking
->rx_handler pointer.
Note that synchronize_net() in netdev_rx_handler_unregister() ensures
this approach as valid.
Introduced originally by:
commit f350a0a87374418635689471606454abc7beaa3a
"bridge: use rx_handler_data pointer to store net_bridge_port pointer"
Fixed but not in the best way by:
commit b5ed54e94d324f17c97852296d61a143f01b227a
"bridge: fix RCU races with bridge port"
Reintroduced by:
commit 716ec052d2280d511e10e90ad54a86f5b5d4dcc2
"bridge: fix NULL pointer deref of br_port_get_rcu"
Please apply to stable trees as well. Thanks.
Reported-by: Laine Stump <laine@redhat.com>
Signed-off-by: Jiri Pirko <jiri@resnulli.us>
---
net/bridge/br_private.h | 12 ++++++++++++
net/bridge/br_stp_bpdu.c | 2 +-
2 files changed, 13 insertions(+), 1 deletion(-)
diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h
index 229d820..67a2d4b 100644
--- a/net/bridge/br_private.h
+++ b/net/bridge/br_private.h
@@ -204,6 +204,13 @@ static inline struct net_bridge_port *br_port_get_rcu(const struct net_device *d
return rcu_dereference(dev->rx_handler_data);
}
+static inline bool br_rx_handler_check_rcu(const struct net_device *dev);
+
+static inline struct net_bridge_port *br_port_get_check_rcu(const struct net_device *dev)
+{
+ return br_rx_handler_check_rcu(dev) ? br_port_get_rcu(dev) : NULL;
+}
+
static inline struct net_bridge_port *br_port_get_rtnl(const struct net_device *dev)
{
return br_port_exists(dev) ?
@@ -426,6 +433,11 @@ netdev_features_t br_features_recompute(struct net_bridge *br,
int br_handle_frame_finish(struct sk_buff *skb);
rx_handler_result_t br_handle_frame(struct sk_buff **pskb);
+static inline bool br_rx_handler_check_rcu(const struct net_device *dev)
+{
+ return rcu_dereference(dev->rx_handler) == br_handle_frame;
+}
+
/* br_ioctl.c */
int br_dev_ioctl(struct net_device *dev, struct ifreq *rq, int cmd);
int br_ioctl_deviceless_stub(struct net *net, unsigned int cmd,
diff --git a/net/bridge/br_stp_bpdu.c b/net/bridge/br_stp_bpdu.c
index 8660ea3..bdb459d 100644
--- a/net/bridge/br_stp_bpdu.c
+++ b/net/bridge/br_stp_bpdu.c
@@ -153,7 +153,7 @@ void br_stp_rcv(const struct stp_proto *proto, struct sk_buff *skb,
if (buf[0] != 0 || buf[1] != 0 || buf[2] != 0)
goto err;
- p = br_port_get_rcu(dev);
+ p = br_port_get_check_rcu(dev);
if (!p)
goto err;
--
1.8.3.1
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [patch net/stable] br: fix use of ->rx_handler_data in code executed on non-rx_handler path
2013-12-05 14:50 [patch net/stable] br: fix use of ->rx_handler_data in code executed on non-rx_handler path Jiri Pirko
@ 2013-12-05 14:58 ` Michael S. Tsirkin
2013-12-05 15:01 ` Jiri Pirko
2013-12-05 15:18 ` Eric Dumazet
1 sibling, 1 reply; 6+ messages in thread
From: Michael S. Tsirkin @ 2013-12-05 14:58 UTC (permalink / raw)
To: Jiri Pirko
Cc: jtluka, netdev, bridge, stephen, edumazet, laine, zhiguohong,
davem
On Thu, Dec 05, 2013 at 03:50:25PM +0100, Jiri Pirko wrote:
> br_stp_rcv() is reached by non-rx_handler path. That means there is no
> guarantee that dev is bridge port and therefore simple NULL check of
> ->rx_handler_data is not enough. There is need to check if dev is really
> bridge port and since only rcu read lock is held here, do it by checking
> ->rx_handler pointer.
>
> Note that synchronize_net() in netdev_rx_handler_unregister() ensures
> this approach as valid.
>
> Introduced originally by:
> commit f350a0a87374418635689471606454abc7beaa3a
> "bridge: use rx_handler_data pointer to store net_bridge_port pointer"
>
> Fixed but not in the best way by:
> commit b5ed54e94d324f17c97852296d61a143f01b227a
> "bridge: fix RCU races with bridge port"
>
> Reintroduced by:
> commit 716ec052d2280d511e10e90ad54a86f5b5d4dcc2
> "bridge: fix NULL pointer deref of br_port_get_rcu"
>
> Please apply to stable trees as well. Thanks.
>
> Reported-by: Laine Stump <laine@redhat.com>
> Signed-off-by: Jiri Pirko <jiri@resnulli.us>
I would also add:
https://bugzilla.redhat.com/show_bug.cgi?id=1025770
> ---
> net/bridge/br_private.h | 12 ++++++++++++
> net/bridge/br_stp_bpdu.c | 2 +-
> 2 files changed, 13 insertions(+), 1 deletion(-)
>
> diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h
> index 229d820..67a2d4b 100644
> --- a/net/bridge/br_private.h
> +++ b/net/bridge/br_private.h
> @@ -204,6 +204,13 @@ static inline struct net_bridge_port *br_port_get_rcu(const struct net_device *d
> return rcu_dereference(dev->rx_handler_data);
> }
>
> +static inline bool br_rx_handler_check_rcu(const struct net_device *dev);
Can't we reorder functions?
Forward-declaring it like this is ugly.
> +
> +static inline struct net_bridge_port *br_port_get_check_rcu(const struct net_device *dev)
> +{
> + return br_rx_handler_check_rcu(dev) ? br_port_get_rcu(dev) : NULL;
> +}
> +
> static inline struct net_bridge_port *br_port_get_rtnl(const struct net_device *dev)
> {
> return br_port_exists(dev) ?
> @@ -426,6 +433,11 @@ netdev_features_t br_features_recompute(struct net_bridge *br,
> int br_handle_frame_finish(struct sk_buff *skb);
> rx_handler_result_t br_handle_frame(struct sk_buff **pskb);
>
> +static inline bool br_rx_handler_check_rcu(const struct net_device *dev)
> +{
> + return rcu_dereference(dev->rx_handler) == br_handle_frame;
> +}
> +
> /* br_ioctl.c */
> int br_dev_ioctl(struct net_device *dev, struct ifreq *rq, int cmd);
> int br_ioctl_deviceless_stub(struct net *net, unsigned int cmd,
> diff --git a/net/bridge/br_stp_bpdu.c b/net/bridge/br_stp_bpdu.c
> index 8660ea3..bdb459d 100644
> --- a/net/bridge/br_stp_bpdu.c
> +++ b/net/bridge/br_stp_bpdu.c
> @@ -153,7 +153,7 @@ void br_stp_rcv(const struct stp_proto *proto, struct sk_buff *skb,
> if (buf[0] != 0 || buf[1] != 0 || buf[2] != 0)
> goto err;
>
> - p = br_port_get_rcu(dev);
> + p = br_port_get_check_rcu(dev);
> if (!p)
> goto err;
>
> --
> 1.8.3.1
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [patch net/stable] br: fix use of ->rx_handler_data in code executed on non-rx_handler path
2013-12-05 14:58 ` Michael S. Tsirkin
@ 2013-12-05 15:01 ` Jiri Pirko
2013-12-05 15:19 ` Eric Dumazet
0 siblings, 1 reply; 6+ messages in thread
From: Jiri Pirko @ 2013-12-05 15:01 UTC (permalink / raw)
To: Michael S. Tsirkin
Cc: netdev, davem, jtluka, zhiguohong, bridge, stephen, edumazet,
laine
Thu, Dec 05, 2013 at 03:58:42PM CET, mst@redhat.com wrote:
>On Thu, Dec 05, 2013 at 03:50:25PM +0100, Jiri Pirko wrote:
>> br_stp_rcv() is reached by non-rx_handler path. That means there is no
>> guarantee that dev is bridge port and therefore simple NULL check of
>> ->rx_handler_data is not enough. There is need to check if dev is really
>> bridge port and since only rcu read lock is held here, do it by checking
>> ->rx_handler pointer.
>>
>> Note that synchronize_net() in netdev_rx_handler_unregister() ensures
>> this approach as valid.
>>
>> Introduced originally by:
>> commit f350a0a87374418635689471606454abc7beaa3a
>> "bridge: use rx_handler_data pointer to store net_bridge_port pointer"
>>
>> Fixed but not in the best way by:
>> commit b5ed54e94d324f17c97852296d61a143f01b227a
>> "bridge: fix RCU races with bridge port"
>>
>> Reintroduced by:
>> commit 716ec052d2280d511e10e90ad54a86f5b5d4dcc2
>> "bridge: fix NULL pointer deref of br_port_get_rcu"
>>
>> Please apply to stable trees as well. Thanks.
>>
>> Reported-by: Laine Stump <laine@redhat.com>
>> Signed-off-by: Jiri Pirko <jiri@resnulli.us>
>
>I would also add:
>https://bugzilla.redhat.com/show_bug.cgi?id=1025770
>
>> ---
>> net/bridge/br_private.h | 12 ++++++++++++
>> net/bridge/br_stp_bpdu.c | 2 +-
>> 2 files changed, 13 insertions(+), 1 deletion(-)
>>
>> diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h
>> index 229d820..67a2d4b 100644
>> --- a/net/bridge/br_private.h
>> +++ b/net/bridge/br_private.h
>> @@ -204,6 +204,13 @@ static inline struct net_bridge_port *br_port_get_rcu(const struct net_device *d
>> return rcu_dereference(dev->rx_handler_data);
>> }
>>
>> +static inline bool br_rx_handler_check_rcu(const struct net_device *dev);
>
>Can't we reorder functions?
>Forward-declaring it like this is ugly.
I know. But makes more sense to have these getters here, near the
struct. I originally moved the definitions near br_handle_frame_finish
definition but I think that it is nicer to do it this way...
>
>> +
>> +static inline struct net_bridge_port *br_port_get_check_rcu(const struct net_device *dev)
>> +{
>> + return br_rx_handler_check_rcu(dev) ? br_port_get_rcu(dev) : NULL;
>> +}
>> +
>> static inline struct net_bridge_port *br_port_get_rtnl(const struct net_device *dev)
>> {
>> return br_port_exists(dev) ?
>> @@ -426,6 +433,11 @@ netdev_features_t br_features_recompute(struct net_bridge *br,
>> int br_handle_frame_finish(struct sk_buff *skb);
>> rx_handler_result_t br_handle_frame(struct sk_buff **pskb);
>>
>> +static inline bool br_rx_handler_check_rcu(const struct net_device *dev)
>> +{
>> + return rcu_dereference(dev->rx_handler) == br_handle_frame;
>> +}
>> +
>> /* br_ioctl.c */
>> int br_dev_ioctl(struct net_device *dev, struct ifreq *rq, int cmd);
>> int br_ioctl_deviceless_stub(struct net *net, unsigned int cmd,
>> diff --git a/net/bridge/br_stp_bpdu.c b/net/bridge/br_stp_bpdu.c
>> index 8660ea3..bdb459d 100644
>> --- a/net/bridge/br_stp_bpdu.c
>> +++ b/net/bridge/br_stp_bpdu.c
>> @@ -153,7 +153,7 @@ void br_stp_rcv(const struct stp_proto *proto, struct sk_buff *skb,
>> if (buf[0] != 0 || buf[1] != 0 || buf[2] != 0)
>> goto err;
>>
>> - p = br_port_get_rcu(dev);
>> + p = br_port_get_check_rcu(dev);
>> if (!p)
>> goto err;
>>
>> --
>> 1.8.3.1
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [patch net/stable] br: fix use of ->rx_handler_data in code executed on non-rx_handler path
2013-12-05 14:50 [patch net/stable] br: fix use of ->rx_handler_data in code executed on non-rx_handler path Jiri Pirko
2013-12-05 14:58 ` Michael S. Tsirkin
@ 2013-12-05 15:18 ` Eric Dumazet
1 sibling, 0 replies; 6+ messages in thread
From: Eric Dumazet @ 2013-12-05 15:18 UTC (permalink / raw)
To: Jiri Pirko
Cc: jtluka, mst, netdev, bridge, stephen, edumazet, laine, zhiguohong,
davem
On Thu, 2013-12-05 at 15:50 +0100, Jiri Pirko wrote:
> br_stp_rcv() is reached by non-rx_handler path. That means there is no
> guarantee that dev is bridge port and therefore simple NULL check of
> ->rx_handler_data is not enough. There is need to check if dev is really
> bridge port and since only rcu read lock is held here, do it by checking
> ->rx_handler pointer.
>
> Note that synchronize_net() in netdev_rx_handler_unregister() ensures
> this approach as valid.
>
> Introduced originally by:
> commit f350a0a87374418635689471606454abc7beaa3a
> "bridge: use rx_handler_data pointer to store net_bridge_port pointer"
>
> Fixed but not in the best way by:
> commit b5ed54e94d324f17c97852296d61a143f01b227a
> "bridge: fix RCU races with bridge port"
>
> Reintroduced by:
> commit 716ec052d2280d511e10e90ad54a86f5b5d4dcc2
> "bridge: fix NULL pointer deref of br_port_get_rcu"
>
> Please apply to stable trees as well. Thanks.
>
> Reported-by: Laine Stump <laine@redhat.com>
> Signed-off-by: Jiri Pirko <jiri@resnulli.us>
> ---
> net/bridge/br_private.h | 12 ++++++++++++
> net/bridge/br_stp_bpdu.c | 2 +-
> 2 files changed, 13 insertions(+), 1 deletion(-)
>
> diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h
> index 229d820..67a2d4b 100644
> --- a/net/bridge/br_private.h
> +++ b/net/bridge/br_private.h
> @@ -204,6 +204,13 @@ static inline struct net_bridge_port *br_port_get_rcu(const struct net_device *d
> return rcu_dereference(dev->rx_handler_data);
> }
>
> +static inline bool br_rx_handler_check_rcu(const struct net_device *dev);
> +
Why doing this ugly forward declaration ?
> +static inline struct net_bridge_port *br_port_get_check_rcu(const struct net_device *dev)
> +{
> + return br_rx_handler_check_rcu(dev) ? br_port_get_rcu(dev) : NULL;
> +}
> +
> static inline struct net_bridge_port *br_port_get_rtnl(const struct net_device *dev)
> {
> return br_port_exists(dev) ?
> @@ -426,6 +433,11 @@ netdev_features_t br_features_recompute(struct net_bridge *br,
> int br_handle_frame_finish(struct sk_buff *skb);
> rx_handler_result_t br_handle_frame(struct sk_buff **pskb);
>
> +static inline bool br_rx_handler_check_rcu(const struct net_device *dev)
> +{
> + return rcu_dereference(dev->rx_handler) == br_handle_frame;
> +}
Move br_port_get_check_rcu() here ?
> +
> /* br_ioctl.c */
> int br_dev_ioctl(struct net_device *dev, struct ifreq *rq, int cmd);
> int br_ioctl_deviceless_stub(struct net *net, unsigned int cmd,
> diff --git a/net/bridge/br_stp_bpdu.c b/net/bridge/br_stp_bpdu.c
> index 8660ea3..bdb459d 100644
> --- a/net/bridge/br_stp_bpdu.c
> +++ b/net/bridge/br_stp_bpdu.c
> @@ -153,7 +153,7 @@ void br_stp_rcv(const struct stp_proto *proto, struct sk_buff *skb,
> if (buf[0] != 0 || buf[1] != 0 || buf[2] != 0)
> goto err;
>
> - p = br_port_get_rcu(dev);
> + p = br_port_get_check_rcu(dev);
> if (!p)
> goto err;
>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [patch net/stable] br: fix use of ->rx_handler_data in code executed on non-rx_handler path
2013-12-05 15:01 ` Jiri Pirko
@ 2013-12-05 15:19 ` Eric Dumazet
2013-12-05 15:21 ` Jiri Pirko
0 siblings, 1 reply; 6+ messages in thread
From: Eric Dumazet @ 2013-12-05 15:19 UTC (permalink / raw)
To: Jiri Pirko
Cc: jtluka, Michael S. Tsirkin, netdev, bridge, stephen, edumazet,
laine, zhiguohong, davem
On Thu, 2013-12-05 at 16:01 +0100, Jiri Pirko wrote:
> I know. But makes more sense to have these getters here, near the
> struct. I originally moved the definitions near br_handle_frame_finish
> definition but I think that it is nicer to do it this way...
No, this is really ugly.
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [patch net/stable] br: fix use of ->rx_handler_data in code executed on non-rx_handler path
2013-12-05 15:19 ` Eric Dumazet
@ 2013-12-05 15:21 ` Jiri Pirko
0 siblings, 0 replies; 6+ messages in thread
From: Jiri Pirko @ 2013-12-05 15:21 UTC (permalink / raw)
To: Eric Dumazet
Cc: Michael S. Tsirkin, netdev, davem, jtluka, zhiguohong, bridge,
stephen, edumazet, laine
Thu, Dec 05, 2013 at 04:19:18PM CET, eric.dumazet@gmail.com wrote:
>On Thu, 2013-12-05 at 16:01 +0100, Jiri Pirko wrote:
>
>> I know. But makes more sense to have these getters here, near the
>> struct. I originally moved the definitions near br_handle_frame_finish
>> definition but I think that it is nicer to do it this way...
>
>No, this is really ugly.
Allright. Will send v2 in a jiffy.
>
>
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2013-12-05 15:21 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2013-12-05 14:50 [patch net/stable] br: fix use of ->rx_handler_data in code executed on non-rx_handler path Jiri Pirko
2013-12-05 14:58 ` Michael S. Tsirkin
2013-12-05 15:01 ` Jiri Pirko
2013-12-05 15:19 ` Eric Dumazet
2013-12-05 15:21 ` Jiri Pirko
2013-12-05 15:18 ` Eric Dumazet
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox