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

From: Paul Moore <[email-masked]>
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 <[email-masked]>

Thanks for sticking with this.

Acked-by: Paul Moore <[email-masked]>

> ---
>  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

-- 
paul moore
www.paul-moore.com