linux-kernel - [PATCH v3 0/2] Restrict dangerous open in sticky directories

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Date:   Wed, 22 Nov 2017 09:01:44 +0100
From:   Salvatore Mesoraca <s.mesoraca16@...il.com>
To:     linux-kernel@...r.kernel.org
Cc:     Kernel Hardening <kernel-hardening@...ts.openwall.com>,
        linux-fsdevel@...r.kernel.org,
        Salvatore Mesoraca <s.mesoraca16@...il.com>,
        Alexander Viro <viro@...iv.linux.org.uk>,
        Jann Horn <jannh@...gle.com>,
        Kees Cook <keescook@...omium.org>,
        Solar Designer <solar@...nwall.com>,
        "Eric W. Biederman" <ebiederm@...ssion.com>
Subject: [PATCH v3 0/2] Restrict dangerous open in sticky directories

This patch-set introduces two separate features aimed at restricting
dangerous open in world or group writable sticky directories.
The purpose is to prevent exploitable bugs in user-space programs
that don't access sticky directories in the proper way.
The first patch prevents the O_CREAT open of FIFOs and regular files
in world or group writable sticky directories, if they already exists
and are owned by someone else.
The second patch prevents O_CREAT open in world or group writable
sticky when the O_EXCL flag is not set, even if the file doesn't
exist yet.
More details can be found in the respective commit messages.

Changes in v3:
	- Fixed format string for uid_t that is unsigned
	  (suggested by Jann Horn).
	- Stop checking if file's and parent dir's owners match in
	  may_create_no_excl. This will allow to discover potential
	  vulnerabilities more easily.

Salvatore Mesoraca (2):
  Protected FIFOs and regular files
  Protected O_CREAT open in sticky directories

 Documentation/sysctl/fs.txt |  66 +++++++++++++++++++++++++
 fs/namei.c                  | 117 ++++++++++++++++++++++++++++++++++++++++++--
 include/linux/fs.h          |   3 ++
 kernel/sysctl.c             |  27 ++++++++++
 4 files changed, 210 insertions(+), 3 deletions(-)

-- 
1.9.1