[1/1] net: fix cipso packet validation when !NETLABEL

When CONFIG_NETLABEL is disabled, the cipso_v4_validate() function could loop
forever in the main loop if opt[opt_iter +1] == 0, this will causing a kernel
crash in an SMP system, since the CPU executing this function will
stall /not respond to IPIs.

This problem can be reproduced by running the IP Stack Integrity Checker
(http://isic.sourceforge.net) using the following command on a Linux machine
connected to DUT:

"icmpsic -s rand -d <DUT IP address> -r 123456"
wait (1-2 min)

Signed-off-by: Seif Mazareeb <seif@marvell.com>
---
 include/net/cipso_ipv4.h | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

--
1.8.1.2

-----Original Message-----
From: Paul Moore [mailto:paul@paul-moore.com] 
Sent: Saturday, October 12, 2013 4:57 AM
To: Seif Mazareeb
Cc: davem@davemloft.net; netdev@vger.kernel.org; thomas.petazzoni@free-electrons.com; Dmitri Epshtein
Subject: Re: [PATCH 1/1] net: fix cipso packet validation when !NETLABEL

On Friday, October 11, 2013 2:04:10 PM Seif Mazareeb wrote:
> When CONFIG_NETLABEL is disabled, the cipso_v4_validate() function 
> could loop forever in the main loop if opt[opt_iter +1] == 0, this 
> will causing a kernel crash in an SMP system, since the CPU executing 
> this function will stall /not respond to IPIs.
> 
> This problem can be reproduced by running the IP Stack Integrity 
> Checker
> (http://isic.sourceforge.net) using the following command on a Linux 
> machine connected to DUT:
> 
> "icmpsic -s rand -d <DUT IP address> -r 123456"
> wait (1-2 min)
> 
> Signed-off-by: Seif Mazareeb <seif@marvell.com>
> ---
>  include/net/cipso_ipv4.h | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/include/net/cipso_ipv4.h b/include/net/cipso_ipv4.h index 
> a7a683e..286b7da 100644
> --- a/include/net/cipso_ipv4.h
> +++ b/include/net/cipso_ipv4.h
> @@ -290,6 +290,7 @@ static inline int cipso_v4_validate(const struct 
> sk_buff *skb, unsigned char err_offset = 0;
>         u8 opt_len = opt[1];
>         u8 opt_iter;
> +       u8 tag_len;
> 
>         if (opt_len < 8) {
>                 err_offset = 1;
> @@ -302,7 +303,8 @@ static inline int cipso_v4_validate(const struct 
> sk_buff *skb, }
> 
>         for (opt_iter = 6; opt_iter < opt_len;) {
> -               if (opt[opt_iter + 1] > (opt_len - opt_iter)) {
> +               tag_len = opt[opt_iter + 1];
> +               if ((tag_len == 0) || (opt[opt_iter + 1] > (opt_len -
> opt_iter))) { err_offset = opt_iter + 1;
>                         goto out;
>                 }

You should also use 'tag_len' inside the for-loop, and after the if-block, where we increment 'opt_iter'.  See my original reply for an example.

--
paul moore
www.paul-moore.com

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On Saturday, October 12, 2013 10:21:50 PM Seif Mazareeb wrote:
> When CONFIG_NETLABEL is disabled, the cipso_v4_validate() function could
> loop forever in the main loop if opt[opt_iter +1] == 0, this will causing a
> kernel crash in an SMP system, since the CPU executing this function will
> stall /not respond to IPIs.
> 
> This problem can be reproduced by running the IP Stack Integrity Checker
> (http://isic.sourceforge.net) using the following command on a Linux machine
> connected to DUT:
> 
> "icmpsic -s rand -d <DUT IP address> -r 123456"
> wait (1-2 min)
> 
> Signed-off-by: Seif Mazareeb <seif@marvell.com>

Thanks for sticking with this.

Acked-by: Paul Moore <paul@paul-moore.com>

> ---
>  include/net/cipso_ipv4.h | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/include/net/cipso_ipv4.h b/include/net/cipso_ipv4.h
> index a7a683e..a8c2ef6 100644
> --- a/include/net/cipso_ipv4.h
> +++ b/include/net/cipso_ipv4.h
> @@ -290,6 +290,7 @@ static inline int cipso_v4_validate(const struct sk_buff
> *skb, unsigned char err_offset = 0;
>         u8 opt_len = opt[1];
>         u8 opt_iter;
> +       u8 tag_len;
> 
>         if (opt_len < 8) {
>                 err_offset = 1;
> @@ -302,11 +303,12 @@ static inline int cipso_v4_validate(const struct
> sk_buff *skb, }
> 
>         for (opt_iter = 6; opt_iter < opt_len;) {
> -               if (opt[opt_iter + 1] > (opt_len - opt_iter)) {
> +               tag_len = opt[opt_iter + 1];
> +               if ((tag_len == 0) || (opt[opt_iter + 1] > (opt_len -
> opt_iter))) { err_offset = opt_iter + 1;
>                         goto out;
>                 }
> -               opt_iter += opt[opt_iter + 1];
> +               opt_iter += tag_len;
>         }
> 
>  out:
> --
> 1.8.1.2

From: Paul Moore <paul@paul-moore.com>
Date: Mon, 14 Oct 2013 11:12:47 -0400

> On Saturday, October 12, 2013 10:21:50 PM Seif Mazareeb wrote:
>> When CONFIG_NETLABEL is disabled, the cipso_v4_validate() function could
>> loop forever in the main loop if opt[opt_iter +1] == 0, this will causing a
>> kernel crash in an SMP system, since the CPU executing this function will
>> stall /not respond to IPIs.
>> 
>> This problem can be reproduced by running the IP Stack Integrity Checker
>> (http://isic.sourceforge.net) using the following command on a Linux machine
>> connected to DUT:
>> 
>> "icmpsic -s rand -d <DUT IP address> -r 123456"
>> wait (1-2 min)
>> 
>> Signed-off-by: Seif Mazareeb <seif@marvell.com>
> 
> Thanks for sticking with this.
> 
> Acked-by: Paul Moore <paul@paul-moore.com>

This patch, like all the others Seif submitted, has been corrupted by
his email client and is this unusable.
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On Thursday, October 17, 2013 03:47:42 PM David Miller wrote:
> From: Paul Moore <paul@paul-moore.com>
> Date: Mon, 14 Oct 2013 11:12:47 -0400
> 
> > On Saturday, October 12, 2013 10:21:50 PM Seif Mazareeb wrote:
> >> When CONFIG_NETLABEL is disabled, the cipso_v4_validate() function could
> >> loop forever in the main loop if opt[opt_iter +1] == 0, this will causing
> >> a
> >> kernel crash in an SMP system, since the CPU executing this function will
> >> stall /not respond to IPIs.
> >> 
> >> This problem can be reproduced by running the IP Stack Integrity Checker
> >> (http://isic.sourceforge.net) using the following command on a Linux
> >> machine connected to DUT:
> >> 
> >> "icmpsic -s rand -d <DUT IP address> -r 123456"
> >> wait (1-2 min)
> >> 
> >> Signed-off-by: Seif Mazareeb <seif@marvell.com>
> > 
> > Thanks for sticking with this.
> > 
> > Acked-by: Paul Moore <paul@paul-moore.com>
> 
> This patch, like all the others Seif submitted, has been corrupted by
> his email client and is this unusable.

Seif, please fix this.  If I don't see a new patch by tomorrow I'll go ahead 
and resubmit.