From mboxrd@z Thu Jan 1 00:00:00 1970 From: Florian Weimer Subject: Re: [RFC PATCH v1 0/5] Add support for O_MAYEXEC References: <20181212081712.32347-1-mic@digikod.net> <20181213030228.GM6830@bombadil.infradead.org> Date: Thu, 13 Dec 2018 06:22:00 +0100 In-Reply-To: <20181213030228.GM6830@bombadil.infradead.org> (Matthew Wilcox's message of "Wed, 12 Dec 2018 19:02:28 -0800") Message-ID: <87bm5qovbb.fsf@oldenburg2.str.redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable To: Matthew Wilcox Cc: =?utf-8?Q?Micka=C3=ABl_Sala=C3=BCn?= , linux-kernel@vger.kernel.org, Al Viro , James Morris , Jonathan Corbet , Kees Cook , Matthew Garrett , Michael Kerrisk , =?utf-8?Q?Micka=C3=ABl_Sala=C3=BCn?= , Mimi Zohar , Philippe =?utf-8?Q?Tr=C3=A9buchet?= , Shuah Khan , Thibaut Sautereau , Vincent Strubel , Yves-Alexis Perez , kernel-hardening@lists.openwall.com, linux-api@vger.kernel.org, linux-security-module@vger.kernel.org, linux-fsdevel@vger.kernel.org List-ID: * Matthew Wilcox: > On Wed, Dec 12, 2018 at 09:17:07AM +0100, Micka=C3=ABl Sala=C3=BCn wrote: >> The goal of this patch series is to control script interpretation. A >> new O_MAYEXEC flag used by sys_open() is added to enable userland script >> interpreter to delegate to the kernel (and thus the system security >> policy) the permission to interpret scripts or other files containing >> what can be seen as commands. > > I don't have a problem with the concept, but we're running low on O_ bits. > Does this have to be done before the process gets a file descriptor, > or could we have a new syscall? Since we're going to be changing the > interpreters anyway, it doesn't seem like too much of an imposition to > ask them to use: > > int verify_for_exec(int fd) > > instead of adding an O_MAYEXEC. Will this work for auditing? Maybe add an interface which explicitly upgrades O_PATH descriptors, and give that a separate flag argument? I suppose that would be more friendly to auditing. Thanks, Florian