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Sat, 26 May 2018 11:48:23 -0400 X-Google-Smtp-Source: AB8JxZoBF9H7I/I1n3mojUQjudDnuvtjHasfKeY8JbPrhTWnRmiS7SHQ0jv1sv3Zt4Yhv9sWDh8ziQ== Date: Sat, 26 May 2018 18:48:19 +0300 From: Alexey Dobriyan To: Salvatore Mesoraca Cc: kernel-hardening@lists.openwall.com, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Andrew Morton , Akinobu Mita , Dmitry Vyukov , Arnd Bergmann , Davidlohr Bueso , Kees Cook Subject: Re: [PATCH] proc: prevent a task from writing on its own /proc/*/mem Message-ID: <20180526154819.GA14016@avx2> References: <1527346246-1334-1-git-send-email-s.mesoraca16@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <1527346246-1334-1-git-send-email-s.mesoraca16@gmail.com> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: owner-linux-security-module@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-Mailing-List: linux-kernel@vger.kernel.org List-ID: On Sat, May 26, 2018 at 04:50:46PM +0200, Salvatore Mesoraca wrote: > Prevent a task from opening, in "write" mode, any /proc/*/mem > file that operates on the task's mm. > /proc/*/mem is mainly a debugging means and, as such, it shouldn't > be used by the inspected process itself. > Current implementation always allow a task to access its own > /proc/*/mem file. > A process can use it to overwrite read-only memory, making > pointless the use of security_file_mprotect() or other ways to > enforce RO memory. You can do it in security_ptrace_access_check() or security_file_open()