From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx3-rdu2.redhat.com ([66.187.233.73]:43458 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1732242AbeGJWnx (ORCPT ); Tue, 10 Jul 2018 18:43:53 -0400 Subject: [PATCH 10/32] tomoyo: Implement security hooks for the new mount API [ver #9] From: David Howells To: viro@zeniv.linux.org.uk Cc: Tetsuo Handa , linux-kernel@vger.kernel.org, dhowells@redhat.com, linux-fsdevel@vger.kernel.org, linux-security-module@vger.kernel.org, tomoyo-dev-en@lists.sourceforge.jp, torvalds@linux-foundation.org Date: Tue, 10 Jul 2018 23:42:37 +0100 Message-ID: <153126255706.14533.4069320423640498264.stgit@warthog.procyon.org.uk> In-Reply-To: <153126248868.14533.9751473662727327569.stgit@warthog.procyon.org.uk> References: <153126248868.14533.9751473662727327569.stgit@warthog.procyon.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-fsdevel-owner@vger.kernel.org List-ID: Implement the security hook to check the creation of a new mountpoint for Tomoyo. As far as I can tell, Tomoyo doesn't make use of the mount data or parse any mount options, so I haven't implemented any of the fs_context hooks for it. Signed-off-by: David Howells cc: Tetsuo Handa cc: tomoyo-dev-en@lists.sourceforge.jp cc: linux-security-module@vger.kernel.org --- security/tomoyo/common.h | 3 +++ security/tomoyo/mount.c | 45 +++++++++++++++++++++++++++++++++++++++++++++ security/tomoyo/tomoyo.c | 15 +++++++++++++++ 3 files changed, 63 insertions(+) diff --git a/security/tomoyo/common.h b/security/tomoyo/common.h index 539bcdd30bb8..e637ce73f7f9 100644 --- a/security/tomoyo/common.h +++ b/security/tomoyo/common.h @@ -971,6 +971,9 @@ int tomoyo_init_request_info(struct tomoyo_request_info *r, const u8 index); int tomoyo_mkdev_perm(const u8 operation, const struct path *path, const unsigned int mode, unsigned int dev); +int tomoyo_mount_permission_fc(struct fs_context *fc, + const struct path *mountpoint, + unsigned int mnt_flags); int tomoyo_mount_permission(const char *dev_name, const struct path *path, const char *type, unsigned long flags, void *data_page); diff --git a/security/tomoyo/mount.c b/security/tomoyo/mount.c index 7dc7f59b7dde..9ec84ab6f5e1 100644 --- a/security/tomoyo/mount.c +++ b/security/tomoyo/mount.c @@ -6,6 +6,7 @@ */ #include +#include #include #include "common.h" @@ -236,3 +237,47 @@ int tomoyo_mount_permission(const char *dev_name, const struct path *path, tomoyo_read_unlock(idx); return error; } + +/** + * tomoyo_mount_permission_fc - Check permission to create a new mount. + * @fc: Context describing the object to be mounted. + * @mountpoint: The target object to mount on. + * @mnt: The MNT_* flags to be set on the mountpoint. + * + * Check the permission to create a mount of the object described in @fc. Note + * that the source object may be a newly created superblock or may be an + * existing one picked from the filesystem (bind mount). + * + * Returns 0 on success, negative value otherwise. + */ +int tomoyo_mount_permission_fc(struct fs_context *fc, + const struct path *mountpoint, + unsigned int mnt_flags) +{ + struct tomoyo_request_info r; + unsigned int ms_flags = 0; + int error; + int idx; + + if (tomoyo_init_request_info(&r, NULL, TOMOYO_MAC_FILE_MOUNT) == + TOMOYO_CONFIG_DISABLED) + return 0; + + /* Convert MNT_* flags to MS_* equivalents. */ + if (mnt_flags & MNT_NOSUID) ms_flags |= MS_NOSUID; + if (mnt_flags & MNT_NODEV) ms_flags |= MS_NODEV; + if (mnt_flags & MNT_NOEXEC) ms_flags |= MS_NOEXEC; + if (mnt_flags & MNT_NOATIME) ms_flags |= MS_NOATIME; + if (mnt_flags & MNT_NODIRATIME) ms_flags |= MS_NODIRATIME; + if (mnt_flags & MNT_RELATIME) ms_flags |= MS_RELATIME; + if (mnt_flags & MNT_READONLY) ms_flags |= MS_RDONLY; + + idx = tomoyo_read_lock(); + /* TODO: There may be multiple sources; for the moment, just pick the + * first if there is one. + */ + error = tomoyo_mount_acl(&r, fc->source, mountpoint, fc->fs_type->name, + ms_flags); + tomoyo_read_unlock(idx); + return error; +} diff --git a/security/tomoyo/tomoyo.c b/security/tomoyo/tomoyo.c index 213b8c593668..31fd6bd4f657 100644 --- a/security/tomoyo/tomoyo.c +++ b/security/tomoyo/tomoyo.c @@ -391,6 +391,20 @@ static int tomoyo_path_chroot(const struct path *path) return tomoyo_path_perm(TOMOYO_TYPE_CHROOT, path, NULL); } +/** + * tomoyo_sb_mount - Target for security_sb_mountpoint(). + * @fc: Context describing the object to be mounted. + * @mountpoint: The target object to mount on. + * @mnt_flags: Mountpoint specific options (as MNT_* flags). + * + * Returns 0 on success, negative value otherwise. + */ +static int tomoyo_sb_mountpoint(struct fs_context *fc, struct path *mountpoint, + unsigned int mnt_flags) +{ + return tomoyo_mount_permission_fc(fc, mountpoint, mnt_flags); +} + /** * tomoyo_sb_mount - Target for security_sb_mount(). * @@ -519,6 +533,7 @@ static struct security_hook_list tomoyo_hooks[] __lsm_ro_after_init = { LSM_HOOK_INIT(path_chmod, tomoyo_path_chmod), LSM_HOOK_INIT(path_chown, tomoyo_path_chown), LSM_HOOK_INIT(path_chroot, tomoyo_path_chroot), + LSM_HOOK_INIT(sb_mountpoint, tomoyo_sb_mountpoint), LSM_HOOK_INIT(sb_mount, tomoyo_sb_mount), LSM_HOOK_INIT(sb_umount, tomoyo_sb_umount), LSM_HOOK_INIT(sb_pivotroot, tomoyo_sb_pivotroot),