1. 26 Sep, 2011 2 commits
  2. 19 Sep, 2011 1 commit
    • Tetsuo Handa's avatar
      TOMOYO: Allow specifying domain transition preference. · 6bce98ed
      Tetsuo Handa authored
      I got an opinion that it is difficult to use exception policy's domain
      transition control directives because they need to match the pathname specified
      to "file execute" directives. For example, if "file execute /bin/\*\-ls\-cat"
      is given, corresponding domain transition control directive needs to be like
      "no_keep_domain /bin/\*\-ls\-cat from any".
      
      If we can specify like below, it will become more convenient.
      
        file execute /bin/ls keep exec.realpath="/bin/ls" exec.argv[0]="ls"
        file execute /bin/cat keep exec.realpath="/bin/cat" exec.argv[0]="cat"
        file execute /bin/\*\-ls\-cat child
        file execute /usr/sbin/httpd <apache> exec.realpath="/usr/sbin/httpd" exec.argv[0]="/usr/sbin/httpd"
      
      In above examples, "keep" works as if keep_domain is specified, "child" works
      as if "no_reset_domain" and "no_initialize_domain" and "no_keep_domain" are
      specified, "<apache>" causes domain transition to <apache> domain upon
      successful execve() operation.
      
      Moreover, we can also allow transition to different domains based on conditions
      like below example.
      
        <kernel> /usr/sbin/sshd
        file execute /bin/bash <kernel> /usr/sbin/sshd //batch-session exec.argc=2 exec.argv[1]="-c"
        file execute /bin/bash <kernel> /usr/sbin/sshd //root-session task.uid=0
        file execute /bin/bash <kernel> /usr/sbin/sshd //nonroot-session task.uid!=0
      Signed-off-by: default avatarTetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
      Signed-off-by: default avatarJames Morris <jmorris@namei.org>
      6bce98ed
  3. 15 Sep, 2011 1 commit
  4. 14 Sep, 2011 10 commits
  5. 13 Sep, 2011 5 commits
  6. 09 Sep, 2011 18 commits
  7. 23 Aug, 2011 2 commits
  8. 22 Aug, 2011 1 commit
    • David Howells's avatar
      KEYS: Correctly destroy key payloads when their keytype is removed · 0c061b57
      David Howells authored
      unregister_key_type() has code to mark a key as dead and make it unavailable in
      one loop and then destroy all those unavailable key payloads in the next loop.
      However, the loop to mark keys dead renders the key undetectable to the second
      loop by changing the key type pointer also.
      
      Fix this by the following means:
      
       (1) The key code has two garbage collectors: one deletes unreferenced keys and
           the other alters keyrings to delete links to old dead, revoked and expired
           keys.  They can end up holding each other up as both want to scan the key
           serial tree under spinlock.  Combine these into a single routine.
      
       (2) Move the dead key marking, dead link removal and dead key removal into the
           garbage collector as a three phase process running over the three cycles
           of the normal garbage collection procedure.  This is tracked by the
           KEY_GC_REAPING_DEAD_1, _2 and _3 state flags.
      
           unregister_key_type() then just unlinks the key type from the list, wakes
           up the garbage collector and waits for the third phase to complete.
      
       (3) Downgrade the key types sem in unregister_key_type() once it has deleted
           the key type from the list so that it doesn't block the keyctl() syscall.
      
       (4) Dead keys that cannot be simply removed in the third phase have their
           payloads destroyed with the key's semaphore write-locked to prevent
           interference by the keyctl() syscall.  There should be no in-kernel users
           of dead keys of that type by the point of unregistration, though keyctl()
           may be holding a reference.
      
       (5) Only perform timer recalculation in the GC if the timer actually expired.
           If it didn't, we'll get another cycle when it goes off - and if the key
           that actually triggered it has been removed, it's not a problem.
      
       (6) Only garbage collect link if the timer expired or if we're doing dead key
           clean up phase 2.
      
       (7) As only key_garbage_collector() is permitted to use rb_erase() on the key
           serial tree, it doesn't need to revalidate its cursor after dropping the
           spinlock as the node the cursor points to must still exist in the tree.
      
       (8) Drop the spinlock in the GC if there is contention on it or if we need to
           reschedule.  After dealing with that, get the spinlock again and resume
           scanning.
      
      This has been tested in the following ways:
      
       (1) Run the keyutils testsuite against it.
      
       (2) Using the AF_RXRPC and RxKAD modules to test keytype removal:
      
           Load the rxrpc_s key type:
      
      	# insmod /tmp/af-rxrpc.ko
      	# insmod /tmp/rxkad.ko
      
           Create a key (http://people.redhat.com/~dhowells/rxrpc/listen.c):
      
      	# /tmp/listen &
      	[1] 8173
      
           Find the key:
      
      	# grep rxrpc_s /proc/keys
      	091086e1 I--Q--     1 perm 39390000     0     0 rxrpc_s   52:2
      
           Link it to a session keyring, preferably one with a higher serial number:
      
      	# keyctl link 0x20e36251 @s
      
           Kill the process (the key should remain as it's linked to another place):
      
      	# fg
      	/tmp/listen
      	^C
      
           Remove the key type:
      
      	rmmod rxkad
      	rmmod af-rxrpc
      
           This can be made a more effective test by altering the following part of
           the patch:
      
      	if (unlikely(gc_state & KEY_GC_REAPING_DEAD_2)) {
      		/* Make sure everyone revalidates their keys if we marked a
      		 * bunch as being dead and make sure all keyring ex-payloads
      		 * are destroyed.
      		 */
      		kdebug("dead sync");
      		synchronize_rcu();
      
           To call synchronize_rcu() in GC phase 1 instead.  That causes that the
           keyring's old payload content to hang around longer until it's RCU
           destroyed - which usually happens after GC phase 3 is complete.  This
           allows the destroy_dead_key branch to be tested.
      Reported-by: default avatarBenjamin Coddington <bcodding@gmail.com>
      Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
      Signed-off-by: default avatarJames Morris <jmorris@namei.org>
      0c061b57