tree 271746ba59ca5b19185574538b5af3e30178c04f
parent 1d9bc6dc5b6b9cc9299739f0245ce4841f066b92
author Eric Paris <eparis@redhat.com> 1291324420 -0500
committer Eric Paris <eparis@redhat.com> 1291324491 -0500

SELinux: do not compute transition labels on mountpoint labeled filesystems

selinux_inode_init_security computes transitions sids even for filesystems
that use mount point labeling.  It shouldn't do that.  It should just use
the mount point label always and no matter what.

This causes 2 problems.  1) it makes file creation slower than it needs to be
since we calculate the transition sid and 2) it allows files to be created
with a different label than the mount point!

# id -Z
staff_u:sysadm_r:sysadm_t:s0-s0:c0.c1023
# sesearch --type --class file --source sysadm_t --target tmp_t
Found 1 semantic te rules:
   type_transition sysadm_t tmp_t : file user_tmp_t;

# mount -o loop,context="system_u:object_r:tmp_t:s0"  /tmp/fs /mnt/tmp

# ls -lZ /mnt/tmp
drwx------. root root system_u:object_r:tmp_t:s0       lost+found
# touch /mnt/tmp/file1
# ls -lZ /mnt/tmp
-rw-r--r--. root root staff_u:object_r:user_tmp_t:s0   file1
drwx------. root root system_u:object_r:tmp_t:s0       lost+found

Whoops, we have a mount point labeled filesystem tmp_t with a user_tmp_t
labeled file!

Signed-off-by: Eric Paris <eparis@redhat.com>
Reviewed-by: Reviewed-by: James Morris <jmorris@namei.org>