linux-kernel - Re: [PATCH 5.4 85/96] selinux: revert "stop passing MAY_NOT_BLOCK to the AVC upon follow

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Message-ID: <b481f512-d4dd-1c04-f39f-0ba271193d0a@tycho.nsa.gov>
Date:   Thu, 13 Feb 2020 11:01:41 -0500
From:   Stephen Smalley <sds@...ho.nsa.gov>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        linux-kernel@...r.kernel.org
Cc:     stable@...r.kernel.org, Will Deacon <will@...nel.org>,
        Paul Moore <paul@...l-moore.com>
Subject: Re: [PATCH 5.4 85/96] selinux: revert "stop passing MAY_NOT_BLOCK to
 the AVC upon follow_link"

On 2/13/20 10:21 AM, Greg Kroah-Hartman wrote:
> From: Stephen Smalley <sds@...ho.nsa.gov>
> 
> commit 1a37079c236d55fb31ebbf4b59945dab8ec8764c upstream.
> 
> This reverts commit e46e01eebbbc ("selinux: stop passing MAY_NOT_BLOCK
> to the AVC upon follow_link"). The correct fix is to instead fall
> back to ref-walk if audit is required irrespective of the specific
> audit data type.  This is done in the next commit.
> 
> Fixes: e46e01eebbbc ("selinux: stop passing MAY_NOT_BLOCK to the AVC upon follow_link")
> Reported-by: Will Deacon <will@...nel.org>
> Signed-off-by: Stephen Smalley <sds@...ho.nsa.gov>
> Signed-off-by: Paul Moore <paul@...l-moore.com>
> Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

This patch should be accompanied by commit 
0188d5c025ca8fe756ba3193bd7d150139af5a88 ("selinux: fall back to 
ref-walk if audit is required").  The former is reverting an incorrect 
fix for bda0be7ad994 ("security: make inode_follow_link RCU-walk 
aware"), the latter is providing the correct fix for it.

> 
> ---
>   security/selinux/avc.c         |   24 ++++++++++++++++++++++--
>   security/selinux/hooks.c       |    5 +++--
>   security/selinux/include/avc.h |    5 +++++
>   3 files changed, 30 insertions(+), 4 deletions(-)

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