Patchwork Bluetooth: Silence static checker warning.

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Submitter santosh nayak
Date Feb. 29, 2012, 5:06 p.m.
Message ID <1330535217-26785-1-git-send-email-santoshprasadnayak@gmail.com>
Download mbox | patch
Permalink /patch/143790/
State Not Applicable
Delegated to: David Miller
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Comments

santosh nayak - Feb. 29, 2012, 5:06 p.m.
From: Santosh Nayak <santoshprasadnayak@gmail.com>

Silencing Static checker warning.
1. Endian warning
2. variable dereferenced before check 'sk' .

Signed-off-by: Santosh Nayak <santoshprasadnayak@gmail.com>
---
 net/bluetooth/l2cap_sock.c |    9 ++++++---
 1 files changed, 6 insertions(+), 3 deletions(-)
Marcel Holtmann - Feb. 29, 2012, 5:39 p.m.
Hi Santosh,

> Silencing Static checker warning.
> 1. Endian warning
> 2. variable dereferenced before check 'sk' .
> 
> Signed-off-by: Santosh Nayak <santoshprasadnayak@gmail.com>
> ---
>  net/bluetooth/l2cap_sock.c |    9 ++++++---
>  1 files changed, 6 insertions(+), 3 deletions(-)
> 
> diff --git a/net/bluetooth/l2cap_sock.c b/net/bluetooth/l2cap_sock.c
> index 401d942..d206321 100644
> --- a/net/bluetooth/l2cap_sock.c
> +++ b/net/bluetooth/l2cap_sock.c
> @@ -82,7 +82,7 @@ static int l2cap_sock_bind(struct socket *sock, struct sockaddr *addr, int alen)
>  	}
>  
>  	if (la.l2_cid)
> -		err = l2cap_add_scid(chan, la.l2_cid);
> +		err = l2cap_add_scid(chan, __le16_to_cpu(la.l2_cid));
>  	else
>  		err = l2cap_add_psm(chan, &la.l2_bdaddr, la.l2_psm);
>  
> @@ -123,7 +123,8 @@ static int l2cap_sock_connect(struct socket *sock, struct sockaddr *addr, int al
>  	if (la.l2_cid && la.l2_psm)
>  		return -EINVAL;
>  
> -	err = l2cap_chan_connect(chan, la.l2_psm, la.l2_cid, &la.l2_bdaddr);
> +	err = l2cap_chan_connect(chan, la.l2_psm, __le16_to_cpu(la.l2_cid),
> +				&la.l2_bdaddr);
>  	if (err)
>  		goto done;

I am not sure about this one. Need to go back and read through the
source code. The value provided from userspace is already in the right
host endian. Could be that we mess up our internal classification. And
instead of adding __le16_to_cpu we should fix its classification.
 
> @@ -795,7 +796,7 @@ static void l2cap_sock_kill(struct sock *sk)
>  static int l2cap_sock_shutdown(struct socket *sock, int how)
>  {
>  	struct sock *sk = sock->sk;
> -	struct l2cap_chan *chan = l2cap_pi(sk)->chan;
> +	struct l2cap_chan *chan;
>  	int err = 0;
>  
>  	BT_DBG("sock %p, sk %p", sock, sk);
> @@ -803,6 +804,8 @@ static int l2cap_sock_shutdown(struct socket *sock, int how)
>  	if (!sk)
>  		return 0;
>  
> +	chan = l2cap_pi(sk)->chan;
> +
>  	lock_sock(sk);
>  	if (!sk->sk_shutdown) {
>  		if (chan->mode == L2CAP_MODE_ERTM)

This one is fine.

Regards

Marcel


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Marcel Holtmann - Feb. 29, 2012, 5:46 p.m.
Hi Santosh,

> > Silencing Static checker warning.
> > 1. Endian warning
> > 2. variable dereferenced before check 'sk' .
> > 
> > Signed-off-by: Santosh Nayak <santoshprasadnayak@gmail.com>
> > ---
> >  net/bluetooth/l2cap_sock.c |    9 ++++++---
> >  1 files changed, 6 insertions(+), 3 deletions(-)
> > 
> > diff --git a/net/bluetooth/l2cap_sock.c b/net/bluetooth/l2cap_sock.c
> > index 401d942..d206321 100644
> > --- a/net/bluetooth/l2cap_sock.c
> > +++ b/net/bluetooth/l2cap_sock.c
> > @@ -82,7 +82,7 @@ static int l2cap_sock_bind(struct socket *sock, struct sockaddr *addr, int alen)
> >  	}
> >  
> >  	if (la.l2_cid)
> > -		err = l2cap_add_scid(chan, la.l2_cid);
> > +		err = l2cap_add_scid(chan, __le16_to_cpu(la.l2_cid));
> >  	else
> >  		err = l2cap_add_psm(chan, &la.l2_bdaddr, la.l2_psm);
> >  
> > @@ -123,7 +123,8 @@ static int l2cap_sock_connect(struct socket *sock, struct sockaddr *addr, int al
> >  	if (la.l2_cid && la.l2_psm)
> >  		return -EINVAL;
> >  
> > -	err = l2cap_chan_connect(chan, la.l2_psm, la.l2_cid, &la.l2_bdaddr);
> > +	err = l2cap_chan_connect(chan, la.l2_psm, __le16_to_cpu(la.l2_cid),
> > +				&la.l2_bdaddr);
> >  	if (err)
> >  		goto done;
> 
> I am not sure about this one. Need to go back and read through the
> source code. The value provided from userspace is already in the right
> host endian. Could be that we mess up our internal classification. And
> instead of adding __le16_to_cpu we should fix its classification.

I confused myself here, so the provided PSM and CID values coming from
userspace are little endian. Patch is correct.

Acked-by: Marcel Holtmann <marcel@holtmann.org>

Regards

Marcel


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Dan Carpenter - Feb. 29, 2012, 7:16 p.m.
On Wed, Feb 29, 2012 at 10:36:57PM +0530, santosh nayak wrote:
> From: Santosh Nayak <santoshprasadnayak@gmail.com>
> 
> Silencing Static checker warning.
> 1. Endian warning

It's not an endian warning, it's an endian bug.  This code won't
work on big endian systems.  Don't mix bugfixes and other changes.

Probably at some point someone will be updating their kernel for
an embedded platform and they'll do a "git log --pretty=oneline" and
they'll notice your endian fix and decide it's super important to
them.  Right now it's hard to find.

regards,
dan carpenter
Andrei Emeltchenko - Feb. 29, 2012, 8:45 p.m.
Hi Santosh,

On Wed, Feb 29, 2012 at 7:06 PM, santosh nayak
<santoshprasadnayak@gmail.com> wrote:
> From: Santosh Nayak <santoshprasadnayak@gmail.com>
>
> Silencing Static checker warning.
> 1. Endian warning
> 2. variable dereferenced before check 'sk' .
>
> Signed-off-by: Santosh Nayak <santoshprasadnayak@gmail.com>
> ---
>  net/bluetooth/l2cap_sock.c |    9 ++++++---
>  1 files changed, 6 insertions(+), 3 deletions(-)
>
> diff --git a/net/bluetooth/l2cap_sock.c b/net/bluetooth/l2cap_sock.c
> index 401d942..d206321 100644
> --- a/net/bluetooth/l2cap_sock.c
> +++ b/net/bluetooth/l2cap_sock.c
> @@ -82,7 +82,7 @@ static int l2cap_sock_bind(struct socket *sock, struct sockaddr *addr, int alen)
>        }
>
>        if (la.l2_cid)
> -               err = l2cap_add_scid(chan, la.l2_cid);
> +               err = l2cap_add_scid(chan, __le16_to_cpu(la.l2_cid));
>        else
>                err = l2cap_add_psm(chan, &la.l2_bdaddr, la.l2_psm);
>
> @@ -123,7 +123,8 @@ static int l2cap_sock_connect(struct socket *sock, struct sockaddr *addr, int al
>        if (la.l2_cid && la.l2_psm)
>                return -EINVAL;
>
> -       err = l2cap_chan_connect(chan, la.l2_psm, la.l2_cid, &la.l2_bdaddr);
> +       err = l2cap_chan_connect(chan, la.l2_psm, __le16_to_cpu(la.l2_cid),
> +                               &la.l2_bdaddr);
>        if (err)
>                goto done;
>
> @@ -795,7 +796,7 @@ static void l2cap_sock_kill(struct sock *sk)
>  static int l2cap_sock_shutdown(struct socket *sock, int how)
>  {
>        struct sock *sk = sock->sk;
> -       struct l2cap_chan *chan = l2cap_pi(sk)->chan;
> +       struct l2cap_chan *chan;
>        int err = 0;
>
>        BT_DBG("sock %p, sk %p", sock, sk);
> @@ -803,6 +804,8 @@ static int l2cap_sock_shutdown(struct socket *sock, int how)
>        if (!sk)
>                return 0;
>
> +       chan = l2cap_pi(sk)->chan;
> +

Didn't I fix this bug already?

http://permalink.gmane.org/gmane.linux.bluez.kernel/21537

Regards,
Andrei
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santosh nayak - March 1, 2012, 5:37 a.m.
@Dan,
           In future patches I will take care of it. Is it ok ? If
required I can resend the patch with required changes on subject line.

@Andrei

In my local clone your changes are  not visible.

What is the schedule of linux-next ?
Is it updated every week or bi-weekly or monthly ?

Regards
Santosh

On Thu, Mar 1, 2012 at 2:15 AM, Andrei Emeltchenko
<andrei.emeltchenko.news@gmail.com> wrote:
> Hi Santosh,
>
> On Wed, Feb 29, 2012 at 7:06 PM, santosh nayak
> <santoshprasadnayak@gmail.com> wrote:
>> From: Santosh Nayak <santoshprasadnayak@gmail.com>
>>
>> Silencing Static checker warning.
>> 1. Endian warning
>> 2. variable dereferenced before check 'sk' .
>>
>> Signed-off-by: Santosh Nayak <santoshprasadnayak@gmail.com>
>> ---
>>  net/bluetooth/l2cap_sock.c |    9 ++++++---
>>  1 files changed, 6 insertions(+), 3 deletions(-)
>>
>> diff --git a/net/bluetooth/l2cap_sock.c b/net/bluetooth/l2cap_sock.c
>> index 401d942..d206321 100644
>> --- a/net/bluetooth/l2cap_sock.c
>> +++ b/net/bluetooth/l2cap_sock.c
>> @@ -82,7 +82,7 @@ static int l2cap_sock_bind(struct socket *sock, struct sockaddr *addr, int alen)
>>        }
>>
>>        if (la.l2_cid)
>> -               err = l2cap_add_scid(chan, la.l2_cid);
>> +               err = l2cap_add_scid(chan, __le16_to_cpu(la.l2_cid));
>>        else
>>                err = l2cap_add_psm(chan, &la.l2_bdaddr, la.l2_psm);
>>
>> @@ -123,7 +123,8 @@ static int l2cap_sock_connect(struct socket *sock, struct sockaddr *addr, int al
>>        if (la.l2_cid && la.l2_psm)
>>                return -EINVAL;
>>
>> -       err = l2cap_chan_connect(chan, la.l2_psm, la.l2_cid, &la.l2_bdaddr);
>> +       err = l2cap_chan_connect(chan, la.l2_psm, __le16_to_cpu(la.l2_cid),
>> +                               &la.l2_bdaddr);
>>        if (err)
>>                goto done;
>>
>> @@ -795,7 +796,7 @@ static void l2cap_sock_kill(struct sock *sk)
>>  static int l2cap_sock_shutdown(struct socket *sock, int how)
>>  {
>>        struct sock *sk = sock->sk;
>> -       struct l2cap_chan *chan = l2cap_pi(sk)->chan;
>> +       struct l2cap_chan *chan;
>>        int err = 0;
>>
>>        BT_DBG("sock %p, sk %p", sock, sk);
>> @@ -803,6 +804,8 @@ static int l2cap_sock_shutdown(struct socket *sock, int how)
>>        if (!sk)
>>                return 0;
>>
>> +       chan = l2cap_pi(sk)->chan;
>> +
>
> Didn't I fix this bug already?
>
> http://permalink.gmane.org/gmane.linux.bluez.kernel/21537
>
> Regards,
> Andrei
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Dan Carpenter - March 1, 2012, 6:25 a.m.
On Thu, Mar 01, 2012 at 11:07:14AM +0530, santosh prasad nayak wrote:
> @Dan,
>            In future patches I will take care of it. Is it ok ? If
> required I can resend the patch with required changes on subject line.
> 

Nope.  Andrei's patch is already in linux-next so you'll have to
redo this.

> @Andrei
> 
> In my local clone your changes are  not visible.
> 
> What is the schedule of linux-next ?
> Is it updated every week or bi-weekly or monthly ?
> 

It's updated every day.  http://linux.f-seidel.de/linux-next/pmwiki/

regards,
dan carpenter
Andrei Emeltchenko - March 1, 2012, 7:43 a.m.
Hi Santosh,

On Thu, Mar 01, 2012 at 11:07:14AM +0530, santosh prasad nayak wrote:
> @Dan,
>            In future patches I will take care of it. Is it ok ? If
> required I can resend the patch with required changes on subject line.
> 
> @Andrei
> 
> In my local clone your changes are  not visible.
> 
> What is the schedule of linux-next ?
> Is it updated every week or bi-weekly or monthly ?

We use Johan's tree so far:
git://git.kernel.org/pub/scm/linux/kernel/git/jh/bluetooth-next.git

I think the tree we use shall be published on bluez.org website.

The change seems to be included to:
"pull request: bluetooth-next 2012-02-24"

http://www.spinics.net/lists/linux-wireless/msg85442.html

Best regards 
Andrei Emeltchenko 


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David Laight - March 2, 2012, 9:15 a.m.
> > > diff --git a/net/bluetooth/l2cap_sock.c
b/net/bluetooth/l2cap_sock.c
> > > index 401d942..d206321 100644
> > > --- a/net/bluetooth/l2cap_sock.c
> > > +++ b/net/bluetooth/l2cap_sock.c
> > > @@ -82,7 +82,7 @@ static int l2cap_sock_bind(struct socket *sock,
struct sockaddr *addr, int alen)
> > >  	}
> > >  
> > >  	if (la.l2_cid)
> > > -		err = l2cap_add_scid(chan, la.l2_cid);
> > > +		err = l2cap_add_scid(chan, __le16_to_cpu(la.l2_cid));
> > >  	else
> > >  		err = l2cap_add_psm(chan, &la.l2_bdaddr, la.l2_psm);
> > >  
> > > @@ -123,7 +123,8 @@ static int l2cap_sock_connect(struct socket
*sock, struct sockaddr *addr, int al
> > >  	if (la.l2_cid && la.l2_psm)
> > >  		return -EINVAL;
> > >  
> > > -	err = l2cap_chan_connect(chan, la.l2_psm, la.l2_cid,
&la.l2_bdaddr);
> > > +	err = l2cap_chan_connect(chan, la.l2_psm,
__le16_to_cpu(la.l2_cid),
> > > +				&la.l2_bdaddr);
> > >  	if (err)
> > >  		goto done;
> > 
> > I am not sure about this one. Need to go back and read through the
> > source code. The value provided from userspace is already in the
right
> > host endian. Could be that we mess up our internal classification.
And
> > instead of adding __le16_to_cpu we should fix its classification.
> 
> I confused myself here, so the provided PSM and CID values coming from
> userspace are little endian. Patch is correct.

How long has this code been in tree?
It isn't obvious to me that this change won't break code on BE systems
where the application code is already fixing the endianness.

	David


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Dan Carpenter - March 2, 2012, 11:04 a.m.
On Fri, Mar 02, 2012 at 09:15:37AM -0000, David Laight wrote:
> How long has this code been in tree?
> It isn't obvious to me that this change won't break code on BE systems
> where the application code is already fixing the endianness.
> 

It looks like we've had an endian bug since last February.

b62f328b8f20a "Bluetooth: Add server socket support for LE
connection"

+               l2cap_pi(sk)->scid = la.l2_cid;

->scid was cpu endian.

regards,
dan carpenter
Marcel Holtmann - March 2, 2012, 5:57 p.m.
Hi Dan,

> > How long has this code been in tree?
> > It isn't obvious to me that this change won't break code on BE systems
> > where the application code is already fixing the endianness.
> > 
> 
> It looks like we've had an endian bug since last February.
> 
> b62f328b8f20a "Bluetooth: Add server socket support for LE
> connection"
> 
> +               l2cap_pi(sk)->scid = la.l2_cid;
> 
> ->scid was cpu endian.

this is a bug. No questions asked.

However you can only exercise this code if you work with Bluetooth Low
Energy and that is not enabled by default since it is not fully finished
yet. CID is only used by Low Energy.

Bluetooth BR/EDR only uses PSM part of the socket address and that has
been endian safe.

Regards

Marcel


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Patch

diff --git a/net/bluetooth/l2cap_sock.c b/net/bluetooth/l2cap_sock.c
index 401d942..d206321 100644
--- a/net/bluetooth/l2cap_sock.c
+++ b/net/bluetooth/l2cap_sock.c
@@ -82,7 +82,7 @@  static int l2cap_sock_bind(struct socket *sock, struct sockaddr *addr, int alen)
 	}
 
 	if (la.l2_cid)
-		err = l2cap_add_scid(chan, la.l2_cid);
+		err = l2cap_add_scid(chan, __le16_to_cpu(la.l2_cid));
 	else
 		err = l2cap_add_psm(chan, &la.l2_bdaddr, la.l2_psm);
 
@@ -123,7 +123,8 @@  static int l2cap_sock_connect(struct socket *sock, struct sockaddr *addr, int al
 	if (la.l2_cid && la.l2_psm)
 		return -EINVAL;
 
-	err = l2cap_chan_connect(chan, la.l2_psm, la.l2_cid, &la.l2_bdaddr);
+	err = l2cap_chan_connect(chan, la.l2_psm, __le16_to_cpu(la.l2_cid),
+				&la.l2_bdaddr);
 	if (err)
 		goto done;
 
@@ -795,7 +796,7 @@  static void l2cap_sock_kill(struct sock *sk)
 static int l2cap_sock_shutdown(struct socket *sock, int how)
 {
 	struct sock *sk = sock->sk;
-	struct l2cap_chan *chan = l2cap_pi(sk)->chan;
+	struct l2cap_chan *chan;
 	int err = 0;
 
 	BT_DBG("sock %p, sk %p", sock, sk);
@@ -803,6 +804,8 @@  static int l2cap_sock_shutdown(struct socket *sock, int how)
 	if (!sk)
 		return 0;
 
+	chan = l2cap_pi(sk)->chan;
+
 	lock_sock(sk);
 	if (!sk->sk_shutdown) {
 		if (chan->mode == L2CAP_MODE_ERTM)