From mboxrd@z Thu Jan 1 00:00:00 1970 From: Djalal Harouni Subject: Re: [PATCH 06/12] procfs: make /proc/*/stack 0400 Date: Sun, 29 Sep 2013 11:37:46 +0100 Message-ID: <20130929103746.GB3459@dztty> References: <1380140085-29712-1-git-send-email-tixxdz@opendz.org> <1380140085-29712-7-git-send-email-tixxdz@opendz.org> Reply-To: kernel-hardening@lists.openwall.com Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: "Eric W. Biederman" , Al Viro , Andrew Morton , Linus Torvalds , Ingo Molnar , "Serge E. Hallyn" , Cyrill Gorcunov , LKML , "linux-fsdevel@vger.kernel.org" , "kernel-hardening@lists.openwall.com" , tixxdz@gmail.com To: Kees Cook Return-path: List-Post: List-Help: List-Unsubscribe: List-Subscribe: Content-Disposition: inline In-Reply-To: List-Id: linux-fsdevel.vger.kernel.org On Thu, Sep 26, 2013 at 03:43:24PM -0500, Kees Cook wrote: > On Wed, Sep 25, 2013 at 3:14 PM, Djalal Harouni wrote: > > The /proc/*/stack contains sensitive information and currently its mode > > is 0444. Change this to 0400 so the VFS will be able to block > > unprivileged processes to get file descriptors on arbitrary privileged > > /proc/*/stack files. > > > > The /proc/*/stack is a /procfs ONE file that shares the same ->open() > > file operation with other ONE files. Doing a ptrace_may_access() check > > during open() might break userspace from accessing other ONE files > > like /proc/*/stat and /proc/*/statm. > > > > Therfore make it 0400 for now, and improve its check during ->read() > > in the next following patch. > > > > Cc: Kees Cook > > Cc: Eric W. Biederman > > Signed-off-by: Djalal Harouni > > While the rest of the series is being discussed, I think it would be > nice to at least get this into the tree. Fixing this reduces which > processes are exposed to ASLR leaks. The rest of the series closes the > remaining holes. Kees I guess it's ok to add your Acked-by for this one, for v2 -- Djalal Harouni http://opendz.org