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[198.145.64.163]) by smtp.gmail.com with ESMTPSA id z7sm818011pff.47.2020.05.13.20.05.10 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 13 May 2020 20:05:11 -0700 (PDT) Date: Wed, 13 May 2020 20:05:09 -0700 From: Kees Cook To: Stephen Smalley Cc: =?iso-8859-1?Q?Micka=EBl_Sala=FCn?= , linux-kernel , Aleksa Sarai , Alexei Starovoitov , Al Viro , Andy Lutomirski , Christian Heimes , Daniel Borkmann , Deven Bowers , Eric Chiang , Florian Weimer , James Morris , Jan Kara , Jann Horn , Jonathan Corbet , Lakshmi Ramasubramanian , Matthew Garrett , Matthew Wilcox , Michael Kerrisk , =?iso-8859-1?Q?Micka=EBl_Sala=FCn?= , Mimi Zohar , Philippe =?iso-8859-1?Q?Tr=E9buchet?= , Scott Shell , Sean Christopherson , Shuah Khan , Steve Dower , Steve Grubb , Thibaut Sautereau , Vincent Strubel , kernel-hardening@lists.openwall.com, linux-api@vger.kernel.org, linux-integrity@vger.kernel.org, LSM List , Linux FS Devel Subject: Re: [PATCH v5 3/6] fs: Enable to enforce noexec mounts or file exec through O_MAYEXEC Message-ID: <202005132002.91B8B63@keescook> References: <20200505153156.925111-1-mic@digikod.net> <20200505153156.925111-4-mic@digikod.net> <202005131525.D08BFB3@keescook> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <202005131525.D08BFB3@keescook> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, May 13, 2020 at 04:27:39PM -0700, Kees Cook wrote: > Like, couldn't just the entire thing just be: > > diff --git a/fs/namei.c b/fs/namei.c > index a320371899cf..0ab18e19f5da 100644 > --- a/fs/namei.c > +++ b/fs/namei.c > @@ -2849,6 +2849,13 @@ static int may_open(const struct path *path, int acc_mode, int flag) > break; > } > > + if (unlikely(mask & MAY_OPENEXEC)) { > + if (sysctl_omayexec_enforce & OMAYEXEC_ENFORCE_MOUNT && > + path_noexec(path)) > + return -EACCES; > + if (sysctl_omayexec_enforce & OMAYEXEC_ENFORCE_FILE) > + acc_mode |= MAY_EXEC; > + } > error = inode_permission(inode, MAY_OPEN | acc_mode); > if (error) > return error; > FYI, I've confirmed this now. Effectively with patch 2 dropped, patch 3 reduced to this plus the Kconfig and sysctl changes, the self tests pass. I think this makes things much cleaner and correct. -- Kees Cook