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| author | Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> | 2012-04-10 20:54:43 -0500 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2012-04-13 08:14:08 -0700 |
| commit | d5748309bb8d75852c92966477277d4572d8920a (patch) | |
| tree | 348be52d97e998fde2273175d23ffce693d1f187 /security | |
| parent | 1a92416a1d37fd96427bd8d8a5fb52b54429c26f (diff) | |
| download | lwn-d5748309bb8d75852c92966477277d4572d8920a.tar.gz lwn-d5748309bb8d75852c92966477277d4572d8920a.zip | |
TOMOYO: Fix mount flags checking order.
commit df91e49477a9be15921cb2854e1d12a3bdb5e425 upstream.
Userspace can pass in arbitrary combinations of MS_* flags to mount().
If both MS_BIND and one of MS_SHARED/MS_PRIVATE/MS_SLAVE/MS_UNBINDABLE are
passed, device name which should be checked for MS_BIND was not checked because
MS_SHARED/MS_PRIVATE/MS_SLAVE/MS_UNBINDABLE had higher priority than MS_BIND.
If both one of MS_BIND/MS_MOVE and MS_REMOUNT are passed, device name which
should not be checked for MS_REMOUNT was checked because MS_BIND/MS_MOVE had
higher priority than MS_REMOUNT.
Fix these bugs by changing priority to MS_REMOUNT -> MS_BIND ->
MS_SHARED/MS_PRIVATE/MS_SLAVE/MS_UNBINDABLE -> MS_MOVE as with do_mount() does.
Also, unconditionally return -EINVAL if more than one of
MS_SHARED/MS_PRIVATE/MS_SLAVE/MS_UNBINDABLE is passed so that TOMOYO will not
generate inaccurate audit logs, for commit 7a2e8a8f "VFS: Sanity check mount
flags passed to change_mnt_propagation()" clarified that these flags must be
exclusively passed.
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: James Morris <james.l.morris@oracle.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'security')
| -rw-r--r-- | security/tomoyo/mount.c | 38 |
1 files changed, 20 insertions, 18 deletions
diff --git a/security/tomoyo/mount.c b/security/tomoyo/mount.c index 9fc2e15841c9..892494ac58e2 100644 --- a/security/tomoyo/mount.c +++ b/security/tomoyo/mount.c @@ -205,30 +205,32 @@ int tomoyo_mount_permission(char *dev_name, struct path *path, char *type, if (flags & MS_REMOUNT) { type = TOMOYO_MOUNT_REMOUNT_KEYWORD; flags &= ~MS_REMOUNT; - } - if (flags & MS_MOVE) { - type = TOMOYO_MOUNT_MOVE_KEYWORD; - flags &= ~MS_MOVE; - } - if (flags & MS_BIND) { + } else if (flags & MS_BIND) { type = TOMOYO_MOUNT_BIND_KEYWORD; flags &= ~MS_BIND; - } - if (flags & MS_UNBINDABLE) { - type = TOMOYO_MOUNT_MAKE_UNBINDABLE_KEYWORD; - flags &= ~MS_UNBINDABLE; - } - if (flags & MS_PRIVATE) { + } else if (flags & MS_SHARED) { + if (flags & (MS_PRIVATE | MS_SLAVE | MS_UNBINDABLE)) + return -EINVAL; + type = TOMOYO_MOUNT_MAKE_SHARED_KEYWORD; + flags &= ~MS_SHARED; + } else if (flags & MS_PRIVATE) { + if (flags & (MS_SHARED | MS_SLAVE | MS_UNBINDABLE)) + return -EINVAL; type = TOMOYO_MOUNT_MAKE_PRIVATE_KEYWORD; flags &= ~MS_PRIVATE; - } - if (flags & MS_SLAVE) { + } else if (flags & MS_SLAVE) { + if (flags & (MS_SHARED | MS_PRIVATE | MS_UNBINDABLE)) + return -EINVAL; type = TOMOYO_MOUNT_MAKE_SLAVE_KEYWORD; flags &= ~MS_SLAVE; - } - if (flags & MS_SHARED) { - type = TOMOYO_MOUNT_MAKE_SHARED_KEYWORD; - flags &= ~MS_SHARED; + } else if (flags & MS_UNBINDABLE) { + if (flags & (MS_SHARED | MS_PRIVATE | MS_SLAVE)) + return -EINVAL; + type = TOMOYO_MOUNT_MAKE_UNBINDABLE_KEYWORD; + flags &= ~MS_UNBINDABLE; + } else if (flags & MS_MOVE) { + type = TOMOYO_MOUNT_MOVE_KEYWORD; + flags &= ~MS_MOVE; } if (!type) type = "<NULL>"; |