From: Tetsuo Handa Date: Wed, 29 Feb 2012 12:53:22 +0000 (+0900) Subject: TOMOYO: Fix mount flags checking order. X-Git-Url: http://git.alex.org.uk TOMOYO: Fix mount flags checking order. BugLink: http://bugs.launchpad.net/bugs/981162 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 Signed-off-by: James Morris Signed-off-by: Greg Kroah-Hartman Signed-off-by: Leann Ogasawara Signed-off-by: Tim Gardner --- diff --git a/security/tomoyo/mount.c b/security/tomoyo/mount.c index bee09d0..fe00cdf 100644 --- a/security/tomoyo/mount.c +++ b/security/tomoyo/mount.c @@ -199,30 +199,32 @@ int tomoyo_mount_permission(char *dev_name, struct path *path, if (flags & MS_REMOUNT) { type = tomoyo_mounts[TOMOYO_MOUNT_REMOUNT]; flags &= ~MS_REMOUNT; - } - if (flags & MS_MOVE) { - type = tomoyo_mounts[TOMOYO_MOUNT_MOVE]; - flags &= ~MS_MOVE; - } - if (flags & MS_BIND) { + } else if (flags & MS_BIND) { type = tomoyo_mounts[TOMOYO_MOUNT_BIND]; flags &= ~MS_BIND; - } - if (flags & MS_UNBINDABLE) { - type = tomoyo_mounts[TOMOYO_MOUNT_MAKE_UNBINDABLE]; - flags &= ~MS_UNBINDABLE; - } - if (flags & MS_PRIVATE) { + } else if (flags & MS_SHARED) { + if (flags & (MS_PRIVATE | MS_SLAVE | MS_UNBINDABLE)) + return -EINVAL; + type = tomoyo_mounts[TOMOYO_MOUNT_MAKE_SHARED]; + flags &= ~MS_SHARED; + } else if (flags & MS_PRIVATE) { + if (flags & (MS_SHARED | MS_SLAVE | MS_UNBINDABLE)) + return -EINVAL; type = tomoyo_mounts[TOMOYO_MOUNT_MAKE_PRIVATE]; flags &= ~MS_PRIVATE; - } - if (flags & MS_SLAVE) { + } else if (flags & MS_SLAVE) { + if (flags & (MS_SHARED | MS_PRIVATE | MS_UNBINDABLE)) + return -EINVAL; type = tomoyo_mounts[TOMOYO_MOUNT_MAKE_SLAVE]; flags &= ~MS_SLAVE; - } - if (flags & MS_SHARED) { - type = tomoyo_mounts[TOMOYO_MOUNT_MAKE_SHARED]; - flags &= ~MS_SHARED; + } else if (flags & MS_UNBINDABLE) { + if (flags & (MS_SHARED | MS_PRIVATE | MS_SLAVE)) + return -EINVAL; + type = tomoyo_mounts[TOMOYO_MOUNT_MAKE_UNBINDABLE]; + flags &= ~MS_UNBINDABLE; + } else if (flags & MS_MOVE) { + type = tomoyo_mounts[TOMOYO_MOUNT_MOVE]; + flags &= ~MS_MOVE; } if (!type) type = "";