linux-kernel - Re: [PATCH] selinux: Fix all those pesky denials breaking my computer

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Message-ID: <CAHC9VhQzfJhioQ6sHkyTAmn1MKWYgBoEA6s9rzTNx3FLBnZXrw@mail.gmail.com>
Date:   Wed, 1 Apr 2020 14:11:47 -0400
From:   Paul Moore <paul@...l-moore.com>
To:     Sultan Alsawaf <sultan@...neltoast.com>
Cc:     Stephen Smalley <sds@...ho.nsa.gov>,
        Eric Paris <eparis@...isplace.org>, selinux@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] selinux: Fix all those pesky denials breaking my computer

On Wed, Apr 1, 2020 at 2:09 PM Sultan Alsawaf <sultan@...neltoast.com> wrote:
> From: Sultan Alsawaf <sultan@...neltoast.com>
>
> I'm sure many of you have found yourself in a position where you've
> tried to increase the security of your system by enabling SELinux, only
> to discover that nothing worked anymore because of those darned 'denial'
> messages. It's clearly an overlooked bug in SELinux!
>
> With a bit of investigation, I discovered that the avc_denied() function
> would erroneously return a non-zero value when I saw those denial
> messages. After slapping in a `return 0;` at the top of that function,
> all was well and my machine with SELinux enforcing was working again!
>
> Signed-off-by: Sultan Alsawaf <sultan@...neltoast.com>
> ---
>  security/selinux/avc.c | 1 +
>  1 file changed, 1 insertion(+)

This is clearly an April Fools joke, but still.  No.

> diff --git a/security/selinux/avc.c b/security/selinux/avc.c
> index d18cb32a242a..b29f19471871 100644
> --- a/security/selinux/avc.c
> +++ b/security/selinux/avc.c
> @@ -1010,6 +1010,7 @@ static noinline int avc_denied(struct selinux_state *state,
>                                u8 driver, u8 xperm, unsigned int flags,
>                                struct av_decision *avd)
>  {
> +       return 0;
>         if (flags & AVC_STRICT)
>                 return -EACCES;
>
> --
> 2.26.0

-- 
paul moore
www.paul-moore.com