android_kernel_google_msm/security
Paul Moore e70d64c16b selinux: correctly label /proc inodes in use before the policy is loaded
commit f64410ec66 upstream.

This patch is based on an earlier patch by Eric Paris, he describes
the problem below:

  "If an inode is accessed before policy load it will get placed on a
   list of inodes to be initialized after policy load.  After policy
   load we call inode_doinit() which calls inode_doinit_with_dentry()
   on all inodes accessed before policy load.  In the case of inodes
   in procfs that means we'll end up at the bottom where it does:

     /* Default to the fs superblock SID. */
     isec->sid = sbsec->sid;

     if ((sbsec->flags & SE_SBPROC) && !S_ISLNK(inode->i_mode)) {
             if (opt_dentry) {
                     isec->sclass = inode_mode_to_security_class(...)
                     rc = selinux_proc_get_sid(opt_dentry,
                                               isec->sclass,
                                               &sid);
                     if (rc)
                             goto out_unlock;
                     isec->sid = sid;
             }
     }

   Since opt_dentry is null, we'll never call selinux_proc_get_sid()
   and will leave the inode labeled with the label on the superblock.
   I believe a fix would be to mimic the behavior of xattrs.  Look
   for an alias of the inode.  If it can't be found, just leave the
   inode uninitialized (and pick it up later) if it can be found, we
   should be able to call selinux_proc_get_sid() ..."

On a system exhibiting this problem, you will notice a lot of files in
/proc with the generic "proc_t" type (at least the ones that were
accessed early in the boot), for example:

   # ls -Z /proc/sys/kernel/shmmax | awk '{ print $4 " " $5 }'
   system_u:object_r:proc_t:s0 /proc/sys/kernel/shmmax

However, with this patch in place we see the expected result:

   # ls -Z /proc/sys/kernel/shmmax | awk '{ print $4 " " $5 }'
   system_u:object_r:sysctl_kernel_t:s0 /proc/sys/kernel/shmmax

Change-Id: I7742b4b7e53b45e4dd13d99c39553a927aa4a7e9
Cc: Eric Paris <eparis@redhat.com>
Signed-off-by: Paul Moore <pmoore@redhat.com>
Acked-by: Eric Paris <eparis@redhat.com>
2015-06-01 16:26:01 -07:00
..
apparmor nick kvfree() from apparmor 2014-11-18 15:13:23 -08:00
integrity security: fix ima kconfig warning 2012-02-28 11:01:15 +11:00
keys usermodehelper: kill umh_wait, renumber UMH_* constants 2012-03-23 16:58:41 -07:00
selinux selinux: correctly label /proc inodes in use before the policy is loaded 2015-06-01 16:26:01 -07:00
smack Smack: move label list initialization 2012-04-18 12:02:28 +10:00
tomoyo usermodehelper: use UMH_WAIT_PROC consistently 2012-03-23 16:58:41 -07:00
yama Yama: add PR_SET_PTRACER_ANY 2012-02-16 10:25:18 +11:00
capability.c Add security hooks to binder and implement the hooks for SELinux. 2013-04-18 16:08:08 -07:00
commoncap.c Add PR_{GET,SET}_NO_NEW_PRIVS to prevent execve from granting privs 2014-10-31 19:46:07 -07:00
device_cgroup.c cgroup: remove cgroup_subsys argument from callbacks 2012-02-02 09:20:22 -08:00
inode.c securityfs: fix object creation races 2012-01-10 10:20:35 -05:00
Kconfig security: Yama LSM 2012-02-10 09:18:52 +11:00
lsm_audit.c security: lsm_audit: add ioctl specific auditing 2015-04-20 09:42:31 -07:00
Makefile security: Yama LSM 2012-02-10 09:18:52 +11:00
min_addr.c
security.c Add security hooks to binder and implement the hooks for SELinux. 2013-04-18 16:08:08 -07:00