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authorTetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>2012-02-29 21:53:22 +0900
committerJames Morris <james.l.morris@oracle.com>2012-03-01 10:23:19 +1100
commitdf91e49477a9be15921cb2854e1d12a3bdb5e425 (patch)
tree8408a7d2a432a206070ac01b2939fefcdce9ca13 /security
parenta69f15890292b5449f9056b4bb322b044e6ce0c6 (diff)
downloadlinaro-lsk-df91e49477a9be15921cb2854e1d12a3bdb5e425.tar.gz
TOMOYO: Fix mount flags checking order.
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>
Diffstat (limited to 'security')
-rw-r--r--security/tomoyo/mount.c38
1 files changed, 20 insertions, 18 deletions
diff --git a/security/tomoyo/mount.c b/security/tomoyo/mount.c
index bee09d06205..fe00cdfd026 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 = "<NULL>";