linux-kernel - [Resend] [PATCH 0/2] procfs: make /proc/*/{stack,syscall,pagemap} 0400

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Date:	Sun, 15 Dec 2013 19:57:12 +0100
From:	Djalal Harouni <tixxdz@...ndz.org>
To:	linux-kernel@...r.kernel.org, kernel-hardening@...ts.openwall.com,
	Andrew Morton <akpm@...ux-foundation.org>,
	Al Viro <viro@...iv.linux.org.uk>,
	"Eric W. Biederman" <ebiederm@...ssion.com>,
	Kees Cook <keescook@...omium.org>,
	Oleg Nesterov <oleg@...hat.com>,
	Andy Lutomirski <luto@...capital.net>
Cc:	Djalal Harouni <tixxdz@...ndz.org>
Subject: [Resend] [PATCH 0/2] procfs: make /proc/*/{stack,syscall,pagemap} 0400

The following patches make /proc/*/{stack,syscall,personality,pagemap}
0400.

These files contain sensitive information that can be used by an
unprivileged process to leak address space and bypass ASLR.

This is a resend, the original discussion:
https://lkml.org/lkml/2013/8/26/354

Ended by confirming this, and Kees Cook Acked the first patch.

Kees Cook also confirmed the security exposure here:
https://lkml.org/lkml/2013/8/28/564

So these patches only restore the original 0400 mode that will make
the VFS able to block unprivileged processes from getting file
descriptors on arbitrary privileged
/proc/*/{stack,syscall,personality,pagemap} files.

>From the first discussion no one picked the patches, so I included them
in the "procfs: protect /proc/*/* entries with file->f_cred" series:
https://lkml.org/lkml/2013/10/1/371

However, that attempt failed to have a general aggreemnt, so I'm
resending again but _only_ those two patches.

At least we have a VFS protection for now.

Djalal Harouni (2):
 procfs: make /proc/*/{stack,syscall,personality} 0400
 procfs: make /proc/*/pagemap 0400

 fs/proc/base.c | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)
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