From: "Mickaël Salaün" <mic@digikod.net>
To: linux-kernel@vger.kernel.org
Cc: "Mickaël Salaün" <mic@digikod.net>,
"Al Viro" <viro@zeniv.linux.org.uk>,
"James Morris" <jmorris@namei.org>,
"Jonathan Corbet" <corbet@lwn.net>,
"Kees Cook" <keescook@chromium.org>,
"Matthew Garrett" <mjg59@google.com>,
"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>,
"Shuah Khan" <shuah@kernel.org>,
"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: [RFC PATCH v1 2/5] fs: Add a MAY_EXECMOUNT flag to infer the noexec mount propertie
Date: Wed, 12 Dec 2018 09:17:09 +0100 [thread overview]
Message-ID: <20181212081712.32347-3-mic@digikod.net> (raw)
In-Reply-To: <20181212081712.32347-1-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 0cab6494978c..de4f33b3f464 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -2970,6 +2970,8 @@ 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 584c9329ad78..083a31b8068e 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -96,6 +96,8 @@ 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
--
2.20.0.rc2
next prev parent reply other threads:[~2018-12-12 8:17 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-12 8:17 [RFC PATCH v1 0/5] Add support for O_MAYEXEC Mickaël Salaün
2018-12-12 8:17 ` [RFC PATCH v1 1/5] fs: Add support for an O_MAYEXEC flag on sys_open() Mickaël Salaün
2018-12-12 14:43 ` Jan Kara
2018-12-12 17:09 ` Mickaël Salaün
2018-12-12 20:42 ` Mimi Zohar
2018-12-13 9:47 ` Matthew Bobrowski
2018-12-13 14:23 ` Mickaël Salaün
2019-04-15 18:47 ` Steve Grubb
2019-04-16 11:49 ` Florian Weimer
2019-04-16 15:34 ` Steve Grubb
2019-04-17 10:01 ` Florian Weimer
2019-04-17 15:04 ` Mickaël Salaün
2019-04-17 14:55 ` Mickaël Salaün
2019-08-04 23:55 ` Andy Lutomirski
2019-08-06 16:40 ` Mickaël Salaün
2018-12-12 8:17 ` Mickaël Salaün [this message]
2018-12-12 8:17 ` [RFC PATCH v1 3/5] Yama: Enforces noexec mounts or file executability through O_MAYEXEC Mickaël Salaün
2018-12-12 14:28 ` Mickaël Salaün
2018-12-12 17:09 ` Jann Horn
2018-12-13 14:49 ` Mickaël Salaün
2019-01-03 11:17 ` Jann Horn
2019-01-08 13:29 ` Mickaël Salaün
2019-01-08 23:30 ` Kees Cook
2019-01-09 13:41 ` Mickaël Salaün
2018-12-12 8:17 ` [RFC PATCH v1 4/5] selftest/yama: Add tests for O_MAYEXEC enforcing Mickaël Salaün
2018-12-12 8:17 ` [RFC PATCH v1 5/5] doc: Add documentation for Yama's open_mayexec_enforce Mickaël Salaün
2018-12-12 16:29 ` [RFC PATCH v1 0/5] Add support for O_MAYEXEC Jordan Glover
2018-12-12 17:01 ` Mickaël Salaün
2018-12-12 19:51 ` James Morris
2018-12-12 20:13 ` Florian Weimer
2018-12-12 23:40 ` James Morris
2018-12-13 5:13 ` Florian Weimer
2018-12-13 14:57 ` Mickaël Salaün
2018-12-13 3:02 ` Matthew Wilcox
2018-12-13 5:22 ` Florian Weimer
2018-12-13 11:04 ` Mimi Zohar
2018-12-13 11:26 ` Florian Weimer
2018-12-13 12:16 ` Mimi Zohar
2018-12-13 12:16 ` Matthew Wilcox
2018-12-13 15:17 ` Mickaël Salaün
2018-12-13 17:13 ` Matthew Wilcox
2018-12-13 17:36 ` Mickaël Salaün
2018-12-13 17:44 ` Matthew Wilcox
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20181212081712.32347-3-mic@digikod.net \
--to=mic@digikod.net \
--cc=corbet@lwn.net \
--cc=jmorris@namei.org \
--cc=keescook@chromium.org \
--cc=kernel-hardening@lists.openwall.com \
--cc=linux-api@vger.kernel.org \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-security-module@vger.kernel.org \
--cc=mickael.salaun@ssi.gouv.fr \
--cc=mjg59@google.com \
--cc=mtk.manpages@gmail.com \
--cc=philippe.trebuchet@ssi.gouv.fr \
--cc=shuah@kernel.org \
--cc=thibaut.sautereau@ssi.gouv.fr \
--cc=vincent.strubel@ssi.gouv.fr \
--cc=viro@zeniv.linux.org.uk \
--cc=yves-alexis.perez@ssi.gouv.fr \
--cc=zohar@linux.ibm.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).