[patch] bridge: make buffer larger in br_setlink()

Subsystems: ethernet bridge, networking [general], the rest

STALE5023d

8 messages, 5 authors, 2012-12-07 · open the first message on its own page

[patch] bridge: make buffer larger in br_setlink()

From: Dan Carpenter <hidden>
Date: 2012-12-07 06:18:54

__IFLA_BRPORT_MAX is one larger than IFLA_BRPORT_MAX.  We pass
IFLA_BRPORT_MAX to nla_parse_nested() so we need IFLA_BRPORT_MAX + 1
elements.  Also Smatch complains that we read past the end of the array
when in br_set_port_flag() when it's called with IFLA_BRPORT_FAST_LEAVE.

Signed-off-by: Dan Carpenter <redacted>
---
Only needed in linux-next.

diff --git a/net/bridge/br_netlink.c b/net/bridge/br_netlink.c
index 850b7d1..cfc5cfe 100644
--- a/net/bridge/br_netlink.c
+++ b/net/bridge/br_netlink.c

@@ -239,7 +239,7 @@ int br_setlink(struct net_device *dev, struct nlmsghdr *nlh)
 	struct ifinfomsg *ifm;
 	struct nlattr *protinfo;
 	struct net_bridge_port *p;
-	struct nlattr *tb[IFLA_BRPORT_MAX];
+	struct nlattr *tb[__IFLA_BRPORT_MAX];
 	int err;
 
 	ifm = nlmsg_data(nlh);

Re: [patch] bridge: make buffer larger in br_setlink()

From: Thomas Graf <tgraf@suug.ch>
Date: 2012-12-07 09:31:14

On 12/07/12 at 09:18am, Dan Carpenter wrote:

quoted hunk

__IFLA_BRPORT_MAX is one larger than IFLA_BRPORT_MAX.  We pass
IFLA_BRPORT_MAX to nla_parse_nested() so we need IFLA_BRPORT_MAX + 1
elements.  Also Smatch complains that we read past the end of the array
when in br_set_port_flag() when it's called with IFLA_BRPORT_FAST_LEAVE.

Signed-off-by: Dan Carpenter <redacted>
---
Only needed in linux-next.

diff --git a/net/bridge/br_netlink.c b/net/bridge/br_netlink.c
index 850b7d1..cfc5cfe 100644
--- a/net/bridge/br_netlink.c
+++ b/net/bridge/br_netlink.c

@@ -239,7 +239,7 @@ int br_setlink(struct net_device *dev, struct nlmsghdr *nlh)
 	struct ifinfomsg *ifm;
 	struct nlattr *protinfo;
 	struct net_bridge_port *p;
-	struct nlattr *tb[IFLA_BRPORT_MAX];
+	struct nlattr *tb[__IFLA_BRPORT_MAX];
 	int err;
 
 	ifm = nlmsg_data(nlh);

I know it's nitpicking but could you use IFLA_BRPORT_MAX+1 for
consistency?

[patch v2] bridge: make buffer larger in br_setlink()

From: Dan Carpenter <hidden>
Date: 2012-12-07 11:10:46

We pass IFLA_BRPORT_MAX to nla_parse_nested() so we need
IFLA_BRPORT_MAX + 1 elements.  Also Smatch complains that we read past
the end of the array when in br_set_port_flag() when it's called with
IFLA_BRPORT_FAST_LEAVE.

Signed-off-by: Dan Carpenter <redacted>
---
v2: Style tweak.

Only needed in linux-next.

diff --git a/net/bridge/br_netlink.c b/net/bridge/br_netlink.c
index 850b7d1..cfc5cfe 100644
--- a/net/bridge/br_netlink.c
+++ b/net/bridge/br_netlink.c

@@ -239,7 +239,7 @@ int br_setlink(struct net_device *dev, struct nlmsghdr *nlh)
 	struct ifinfomsg *ifm;
 	struct nlattr *protinfo;
 	struct net_bridge_port *p;
-	struct nlattr *tb[IFLA_BRPORT_MAX];
+	struct nlattr *tb[IFLA_BRPORT_MAX + 1];
 	int err;
 
 	ifm = nlmsg_data(nlh);

Re: [patch v2] bridge: make buffer larger in br_setlink()

From: walter harms <hidden>
Date: 2012-12-07 16:07:28


Am 07.12.2012 12:10, schrieb Dan Carpenter:

We pass IFLA_BRPORT_MAX to nla_parse_nested() so we need
IFLA_BRPORT_MAX + 1 elements.  Also Smatch complains that we read past
the end of the array when in br_set_port_flag() when it's called with
IFLA_BRPORT_FAST_LEAVE.



I have no clue why nla_parse_nested() need IFLA_BRPORT_MAX elements.
but the majory of loop look like
for(i=0;i<max;++)
most programmers will think this way.
So it seems the place to fix is nla_parse_nested().
doing not so is asking for trouble (in the long run).
At least this function needs a big warning label that (max-1)
is actually needed.


just my two cents,
 wh

quoted hunk

Signed-off-by: Dan Carpenter <redacted>
---
v2: Style tweak.

Only needed in linux-next.

diff --git a/net/bridge/br_netlink.c b/net/bridge/br_netlink.c
index 850b7d1..cfc5cfe 100644
--- a/net/bridge/br_netlink.c
+++ b/net/bridge/br_netlink.c

@@ -239,7 +239,7 @@ int br_setlink(struct net_device *dev, struct nlmsghdr *nlh)
 	struct ifinfomsg *ifm;
 	struct nlattr *protinfo;
 	struct net_bridge_port *p;
-	struct nlattr *tb[IFLA_BRPORT_MAX];
+	struct nlattr *tb[IFLA_BRPORT_MAX + 1];
 	int err;
 
 	ifm = nlmsg_data(nlh);

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Re: [patch v2] bridge: make buffer larger in br_setlink()

From: Stephen Hemminger <hidden>
Date: 2012-12-07 17:08:00


----- Original Message -----

quoted hunk

We pass IFLA_BRPORT_MAX to nla_parse_nested() so we need
IFLA_BRPORT_MAX + 1 elements.  Also Smatch complains that we read
past
the end of the array when in br_set_port_flag() when it's called with
IFLA_BRPORT_FAST_LEAVE.

Signed-off-by: Dan Carpenter <redacted>
---
v2: Style tweak.

Only needed in linux-next.

diff --git a/net/bridge/br_netlink.c b/net/bridge/br_netlink.c
index 850b7d1..cfc5cfe 100644
--- a/net/bridge/br_netlink.c
+++ b/net/bridge/br_netlink.c

@@ -239,7 +239,7 @@ int br_setlink(struct net_device *dev, struct

nlmsghdr *nlh)
 	struct ifinfomsg *ifm;
 	struct nlattr *protinfo;
 	struct net_bridge_port *p;
-	struct nlattr *tb[IFLA_BRPORT_MAX];
+	struct nlattr *tb[IFLA_BRPORT_MAX + 1];
 	int err;
 
 	ifm = nlmsg_data(nlh);

Acked-by: Stephen Hemminger <redacted>

Re: [patch v2] bridge: make buffer larger in br_setlink()

From: Dan Carpenter <hidden>
Date: 2012-12-07 18:53:59

On Fri, Dec 07, 2012 at 05:07:24PM +0100, walter harms wrote:


Am 07.12.2012 12:10, schrieb Dan Carpenter:

quoted

We pass IFLA_BRPORT_MAX to nla_parse_nested() so we need
IFLA_BRPORT_MAX + 1 elements.  Also Smatch complains that we read past
the end of the array when in br_set_port_flag() when it's called with
IFLA_BRPORT_FAST_LEAVE.



I have no clue why nla_parse_nested() need IFLA_BRPORT_MAX elements.
but the majory of loop look like
for(i=0;i<max;++)
most programmers will think this way.
So it seems the place to fix is nla_parse_nested().
doing not so is asking for trouble (in the long run).
At least this function needs a big warning label that (max-1)
is actually needed.

Yeah, nla_parse_nested() is actually documented already.

regards,
dan carpenter

Re: [patch v2] bridge: make buffer larger in br_setlink()

From: walter harms <hidden>
Date: 2012-12-07 19:15:44


Am 07.12.2012 19:53, schrieb Dan Carpenter:

On Fri, Dec 07, 2012 at 05:07:24PM +0100, walter harms wrote:

quoted


Am 07.12.2012 12:10, schrieb Dan Carpenter:

quoted

We pass IFLA_BRPORT_MAX to nla_parse_nested() so we need
IFLA_BRPORT_MAX + 1 elements.  Also Smatch complains that we read past
the end of the array when in br_set_port_flag() when it's called with
IFLA_BRPORT_FAST_LEAVE.



I have no clue why nla_parse_nested() need IFLA_BRPORT_MAX elements.
but the majory of loop look like
for(i=0;i<max;++)
most programmers will think this way.
So it seems the place to fix is nla_parse_nested().
doing not so is asking for trouble (in the long run).
At least this function needs a big warning label that (max-1)
is actually needed.

Yeah, nla_parse_nested() is actually documented already.


documenting unexspected behavier is not as much helpfull as changing it.

just my 2 cents,
 wh

Re: [patch v2] bridge: make buffer larger in br_setlink()

From: David Miller <davem@davemloft.net>
Date: 2012-12-07 19:40:54

From: Dan Carpenter <redacted>
Date: Fri, 7 Dec 2012 14:10:46 +0300

We pass IFLA_BRPORT_MAX to nla_parse_nested() so we need
IFLA_BRPORT_MAX + 1 elements.  Also Smatch complains that we read past
the end of the array when in br_set_port_flag() when it's called with
IFLA_BRPORT_FAST_LEAVE.

Signed-off-by: Dan Carpenter <redacted>

Applied.

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