From: "Mickaël Salaün" <mic@digikod.net> To: linux-kernel@vger.kernel.org Cc: "Mickaël Salaün" <mic@digikod.net>, "Aleksa Sarai" <cyphar@cyphar.com>, "Alexei Starovoitov" <ast@kernel.org>, "Al Viro" <viro@zeniv.linux.org.uk>, "Andy Lutomirski" <luto@kernel.org>, "Christian Heimes" <christian@python.org>, "Daniel Borkmann" <daniel@iogearbox.net>, "Eric Chiang" <ericchiang@google.com>, "Florian Weimer" <fweimer@redhat.com>, "James Morris" <jmorris@namei.org>, "Jan Kara" <jack@suse.cz>, "Jann Horn" <jannh@google.com>, "Jonathan Corbet" <corbet@lwn.net>, "Kees Cook" <keescook@chromium.org>, "Matthew Garrett" <mjg59@google.com>, "Matthew Wilcox" <willy@infradead.org>, "Michael Kerrisk" <mtk.manpages@gmail.com>, "Mickaël Salaün" <mickael.salaun@ssi.gouv.fr>, "Mimi Zohar" <zohar@linux.ibm.com>, "Philippe Trébuchet" <philippe.trebuchet@ssi.gouv.fr>, "Scott Shell" <scottsh@microsoft.com>, "Sean Christopherson" <sean.j.christopherson@intel.com>, "Shuah Khan" <shuah@kernel.org>, "Song Liu" <songliubraving@fb.com>, "Steve Dower" <steve.dower@python.org>, "Steve Grubb" <sgrubb@redhat.com>, "Thibaut Sautereau" <thibaut.sautereau@ssi.gouv.fr>, "Vincent Strubel" <vincent.strubel@ssi.gouv.fr>, "Yves-Alexis Perez" <yves-alexis.perez@ssi.gouv.fr>, kernel-hardening@lists.openwall.com, linux-api@vger.kernel.org, linux-security-module@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: [PATCH v2 2/5] fs: Add a MAY_EXECMOUNT flag to infer the noexec mount propertie Date: Fri, 6 Sep 2019 17:24:52 +0200 [thread overview] Message-ID: <20190906152455.22757-3-mic@digikod.net> (raw) In-Reply-To: <20190906152455.22757-1-mic@digikod.net> An LSM doesn't get path information related to an access request to open an inode. This new (internal) MAY_EXECMOUNT flag enables an LSM to check if the underlying mount point of an inode is marked as executable. This is useful to implement a security policy taking advantage of the noexec mount option. This flag is set according to path_noexec(), which checks if a mount point is mounted with MNT_NOEXEC or if the underlying superblock is SB_I_NOEXEC. Signed-off-by: Mickaël Salaün <mic@digikod.net> Reviewed-by: Philippe Trébuchet <philippe.trebuchet@ssi.gouv.fr> Reviewed-by: Thibaut Sautereau <thibaut.sautereau@ssi.gouv.fr> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Kees Cook <keescook@chromium.org> Cc: Mickaël Salaün <mickael.salaun@ssi.gouv.fr> --- fs/namei.c | 2 ++ include/linux/fs.h | 2 ++ 2 files changed, 4 insertions(+) diff --git a/fs/namei.c b/fs/namei.c index 209c51a5226c..0a6b9483d0cb 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -2968,6 +2968,8 @@ static int may_open(const struct path *path, int acc_mode, int flag) break; } + /* Pass the mount point executability. */ + acc_mode |= path_noexec(path) ? 0 : MAY_EXECMOUNT; error = inode_permission(inode, MAY_OPEN | acc_mode); if (error) return error; diff --git a/include/linux/fs.h b/include/linux/fs.h index 848f5711bdf0..e57609dac8dd 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -101,6 +101,8 @@ typedef int (dio_iodone_t)(struct kiocb *iocb, loff_t offset, #define MAY_NOT_BLOCK 0x00000080 /* the inode is opened with O_MAYEXEC */ #define MAY_OPENEXEC 0x00000100 +/* the mount point is marked as executable */ +#define MAY_EXECMOUNT 0x00000200 /* * flags in file.f_mode. Note that FMODE_READ and FMODE_WRITE must correspond -- 2.23.0
WARNING: multiple messages have this Message-ID (diff)
From: "Mickaël Salaün" <mic@digikod.net> To: linux-kernel@vger.kernel.org Cc: "Mickaël Salaün" <mic@digikod.net>, "Aleksa Sarai" <cyphar@cyphar.com>, "Alexei Starovoitov" <ast@kernel.org>, "Al Viro" <viro@zeniv.linux.org.uk>, "Andy Lutomirski" <luto@kernel.org>, "Christian Heimes" <christian@python.org>, "Daniel Borkmann" <daniel@iogearbox.net>, "Eric Chiang" <ericchiang@google.com>, "Florian Weimer" <fweimer@redhat.com>, "James Morris" <jmorris@namei.org>, "Jan Kara" <jack@suse.cz>, "Jann Horn" <jannh@google.com>, "Jonathan Corbet" <corbet@lwn.net>, "Kees Cook" <keescook@chromium.org>, "Matthew Garrett" <mjg59@google.com>, "Matthew Wilcox" <willy@infradead.org>, "Michael Kerrisk" <mtk.manpages@gmail.com>, "Mickaël Salaün" <mickael.salaun@ssi.gouv.fr>, "Mimi Zohar" <zohar@linux.ibm.com> Subject: [PATCH v2 2/5] fs: Add a MAY_EXECMOUNT flag to infer the noexec mount propertie Date: Fri, 6 Sep 2019 17:24:52 +0200 [thread overview] Message-ID: <20190906152455.22757-3-mic@digikod.net> (raw) In-Reply-To: <20190906152455.22757-1-mic@digikod.net> An LSM doesn't get path information related to an access request to open an inode. This new (internal) MAY_EXECMOUNT flag enables an LSM to check if the underlying mount point of an inode is marked as executable. This is useful to implement a security policy taking advantage of the noexec mount option. This flag is set according to path_noexec(), which checks if a mount point is mounted with MNT_NOEXEC or if the underlying superblock is SB_I_NOEXEC. Signed-off-by: Mickaël Salaün <mic@digikod.net> Reviewed-by: Philippe Trébuchet <philippe.trebuchet@ssi.gouv.fr> Reviewed-by: Thibaut Sautereau <thibaut.sautereau@ssi.gouv.fr> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Kees Cook <keescook@chromium.org> Cc: Mickaël Salaün <mickael.salaun@ssi.gouv.fr> --- fs/namei.c | 2 ++ include/linux/fs.h | 2 ++ 2 files changed, 4 insertions(+) diff --git a/fs/namei.c b/fs/namei.c index 209c51a5226c..0a6b9483d0cb 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -2968,6 +2968,8 @@ static int may_open(const struct path *path, int acc_mode, int flag) break; } + /* Pass the mount point executability. */ + acc_mode |= path_noexec(path) ? 0 : MAY_EXECMOUNT; error = inode_permission(inode, MAY_OPEN | acc_mode); if (error) return error; diff --git a/include/linux/fs.h b/include/linux/fs.h index 848f5711bdf0..e57609dac8dd 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -101,6 +101,8 @@ typedef int (dio_iodone_t)(struct kiocb *iocb, loff_t offset, #define MAY_NOT_BLOCK 0x00000080 /* the inode is opened with O_MAYEXEC */ #define MAY_OPENEXEC 0x00000100 +/* the mount point is marked as executable */ +#define MAY_EXECMOUNT 0x00000200 /* * flags in file.f_mode. Note that FMODE_READ and FMODE_WRITE must correspond -- 2.23.0
next prev parent reply other threads:[~2019-09-06 15:26 UTC|newest] Thread overview: 90+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-09-06 15:24 [PATCH v2 0/5] Add support for O_MAYEXEC Mickaël Salaün 2019-09-06 15:24 ` Mickaël Salaün 2019-09-06 15:24 ` [PATCH v2 1/5] fs: Add support for an O_MAYEXEC flag on sys_open() Mickaël Salaün 2019-09-06 15:24 ` Mickaël Salaün 2019-09-06 15:56 ` Florian Weimer 2019-09-06 15:56 ` Florian Weimer 2019-09-06 16:06 ` Mickaël Salaün 2019-09-06 16:06 ` Mickaël Salaün 2019-09-06 16:48 ` Jeff Layton 2019-09-06 16:48 ` Jeff Layton 2019-09-06 17:13 ` Aleksa Sarai 2019-09-06 17:13 ` Aleksa Sarai 2019-09-06 19:43 ` Jeff Layton 2019-09-06 19:43 ` Jeff Layton 2019-09-06 20:06 ` Andy Lutomirski 2019-09-06 20:06 ` Andy Lutomirski 2019-09-06 20:51 ` Jeff Layton 2019-09-06 20:51 ` Jeff Layton 2019-09-06 21:27 ` Andy Lutomirski 2019-09-06 21:27 ` Andy Lutomirski 2019-09-06 22:12 ` Aleksa Sarai 2019-09-06 22:12 ` Aleksa Sarai 2019-09-09 9:33 ` Mickaël Salaün 2019-09-09 9:33 ` Mickaël Salaün 2019-09-06 22:05 ` Aleksa Sarai 2019-09-06 22:05 ` Aleksa Sarai 2019-09-06 22:18 ` Aleksa Sarai 2019-09-06 22:18 ` Aleksa Sarai 2019-09-06 17:14 ` Mickaël Salaün 2019-09-06 17:14 ` Mickaël Salaün 2019-09-06 18:38 ` Jeff Layton 2019-09-06 18:38 ` Jeff Layton 2019-09-06 18:41 ` Andy Lutomirski 2019-09-06 18:41 ` Andy Lutomirski 2019-09-09 9:18 ` Mickaël Salaün 2019-09-09 9:18 ` Mickaël Salaün 2019-09-09 15:49 ` Andy Lutomirski 2019-09-09 15:49 ` Andy Lutomirski 2019-09-06 18:44 ` Florian Weimer 2019-09-06 18:44 ` Florian Weimer 2019-09-06 19:03 ` James Morris 2019-09-06 19:03 ` James Morris 2019-09-09 9:25 ` Mickaël Salaün 2019-09-09 9:25 ` Mickaël Salaün 2019-09-09 10:12 ` James Morris 2019-09-09 10:12 ` James Morris 2019-09-09 10:54 ` Mickaël Salaün 2019-09-09 10:54 ` Mickaël Salaün 2019-09-09 12:28 ` Aleksa Sarai 2019-09-09 12:28 ` Aleksa Sarai 2019-09-09 12:33 ` Mickaël Salaün 2019-09-09 12:33 ` Mickaël Salaün 2019-09-09 11:54 ` Aleksa Sarai 2019-09-09 11:54 ` Aleksa Sarai 2019-09-09 12:28 ` Mickaël Salaün 2019-09-09 12:28 ` Mickaël Salaün 2019-09-06 17:07 ` Aleksa Sarai 2019-09-06 17:07 ` Aleksa Sarai 2019-09-06 17:20 ` Christian Brauner 2019-09-06 17:20 ` Christian Brauner 2019-09-06 17:24 ` Mickaël Salaün 2019-09-06 17:24 ` Mickaël Salaün 2019-09-06 17:40 ` Tycho Andersen 2019-09-06 17:40 ` Tycho Andersen 2019-09-06 18:27 ` Florian Weimer 2019-09-06 18:27 ` Florian Weimer 2019-09-06 18:46 ` Tycho Andersen 2019-09-06 18:46 ` Tycho Andersen 2019-09-06 15:24 ` Mickaël Salaün [this message] 2019-09-06 15:24 ` [PATCH v2 2/5] fs: Add a MAY_EXECMOUNT flag to infer the noexec mount propertie Mickaël Salaün 2019-09-06 15:24 ` [PATCH v2 3/5] fs: Enable to enforce noexec mounts or file exec through O_MAYEXEC Mickaël Salaün 2019-09-06 15:24 ` Mickaël Salaün 2019-09-06 15:24 ` [PATCH v2 4/5] selftest/exec: Add tests for O_MAYEXEC enforcing Mickaël Salaün 2019-09-06 15:24 ` Mickaël Salaün 2019-09-06 15:24 ` [PATCH v2 5/5] doc: Add documentation for the fs.open_mayexec_enforce sysctl Mickaël Salaün 2019-09-06 15:24 ` Mickaël Salaün 2019-09-06 18:50 ` [PATCH v2 0/5] Add support for O_MAYEXEC Steve Grubb 2019-09-06 18:50 ` Steve Grubb 2019-09-06 18:57 ` Florian Weimer 2019-09-06 18:57 ` Florian Weimer 2019-09-06 19:07 ` Steve Grubb 2019-09-06 19:07 ` Steve Grubb 2019-09-06 19:26 ` Andy Lutomirski 2019-09-06 19:26 ` Andy Lutomirski 2019-09-06 22:44 ` Aleksa Sarai 2019-09-06 22:44 ` Aleksa Sarai 2019-09-09 9:09 ` Mickaël Salaün 2019-09-09 9:09 ` Mickaël Salaün 2019-09-09 0:16 ` James Morris 2019-09-09 0:16 ` James Morris
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