Re: [PATCH] SELinux: BUG in SELinux compat_net code

[Paul Moore]

On Tuesday 19 May 2009 05:41:58 pm Eric Paris wrote:
> This patch is not applicable to Linus's tree as the code in question has
> been removed for 2.6.30.  I'm sending in case any of the stable
> maintainers would like to push to their branches (which I think anything
> pre 2.6.30 would like to do).
>
> Ubuntu users were experiencing a kernel panic when they enabled SELinux
> due to an old bug in our handling of the compatibility mode network
> controls, introduced Jan 1 2008 effad8df44261031a882e1a895415f7186a5098e
> Most distros have not used the compat_net code since the new code was
> introduced and so noone has hit this problem before.  Ubuntu is the only
> distro I know that enabled that legacy cruft by default.  But, I was ask
> to look at it and found that the above patch changed a call to
> avc_has_perm from if(send_perm) to if(!send_perm) in
> selinux_ip_postroute_iptables_compat().  The result is that users who
> turn on SELinux and have compat_net set can (and oftern will) BUG() in
> avc_has_perm_noaudit since they are requesting 0 permissions.
>
> This patch corrects that accidental bug introduction.
>
> Signed-off-by: Eric Paris <eparis@xxxxxxxxxx>

My mistake, thanks to Eric for catching and fixing this bug.

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

> ---
>
>  security/selinux/hooks.c |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff -up linux-source-2.6.28/security/selinux/hooks.c.pre.send
> linux-source-2.6.28/security/selinux/hooks.c ---
> linux-source-2.6.28/security/selinux/hooks.c.pre.send	2009-05-18
> 13:23:16.043632602 -0400 +++
> linux-source-2.6.28/security/selinux/hooks.c	2009-05-18 13:23:27.899632772
> -0400 @@ -4561,7 +4561,7 @@ static int selinux_ip_postroute_iptables
>  	if (err)
>  		return err;
>
> -	if (send_perm != 0)
> +	if (!send_perm)
>  		return 0;
>
>  	err = sel_netport_sid(sk->sk_protocol,

-- 
paul moore
linux @ hp

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