Commit Graph

58 Commits

Author SHA1 Message Date
Linus Torvalds 2a74dbb9a8 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security
Pull security subsystem updates from James Morris:
 "A quiet cycle for the security subsystem with just a few maintenance
  updates."

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security:
  Smack: create a sysfs mount point for smackfs
  Smack: use select not depends in Kconfig
  Yama: remove locking from delete path
  Yama: add RCU to drop read locking
  drivers/char/tpm: remove tasklet and cleanup
  KEYS: Use keyring_alloc() to create special keyrings
  KEYS: Reduce initial permissions on keys
  KEYS: Make the session and process keyrings per-thread
  seccomp: Make syscall skipping and nr changes more consistent
  key: Fix resource leak
  keys: Fix unreachable code
  KEYS: Add payload preparsing opportunity prior to key instantiate or update
2012-12-16 15:40:50 -08:00
Linus Torvalds d25282d1c9 Merge branch 'modules-next' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux
Pull module signing support from Rusty Russell:
 "module signing is the highlight, but it's an all-over David Howells frenzy..."

Hmm "Magrathea: Glacier signing key". Somebody has been reading too much HHGTTG.

* 'modules-next' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux: (37 commits)
  X.509: Fix indefinite length element skip error handling
  X.509: Convert some printk calls to pr_devel
  asymmetric keys: fix printk format warning
  MODSIGN: Fix 32-bit overflow in X.509 certificate validity date checking
  MODSIGN: Make mrproper should remove generated files.
  MODSIGN: Use utf8 strings in signer's name in autogenerated X.509 certs
  MODSIGN: Use the same digest for the autogen key sig as for the module sig
  MODSIGN: Sign modules during the build process
  MODSIGN: Provide a script for generating a key ID from an X.509 cert
  MODSIGN: Implement module signature checking
  MODSIGN: Provide module signing public keys to the kernel
  MODSIGN: Automatically generate module signing keys if missing
  MODSIGN: Provide Kconfig options
  MODSIGN: Provide gitignore and make clean rules for extra files
  MODSIGN: Add FIPS policy
  module: signature checking hook
  X.509: Add a crypto key parser for binary (DER) X.509 certificates
  MPILIB: Provide a function to read raw data into an MPI
  X.509: Add an ASN.1 decoder
  X.509: Add simple ASN.1 grammar compiler
  ...
2012-10-14 13:39:34 -07:00
David Howells cf7f601c06 KEYS: Add payload preparsing opportunity prior to key instantiate or update
Give the key type the opportunity to preparse the payload prior to the
instantiation and update routines being called.  This is done with the
provision of two new key type operations:

	int (*preparse)(struct key_preparsed_payload *prep);
	void (*free_preparse)(struct key_preparsed_payload *prep);

If the first operation is present, then it is called before key creation (in
the add/update case) or before the key semaphore is taken (in the update and
instantiate cases).  The second operation is called to clean up if the first
was called.

preparse() is given the opportunity to fill in the following structure:

	struct key_preparsed_payload {
		char		*description;
		void		*type_data[2];
		void		*payload;
		const void	*data;
		size_t		datalen;
		size_t		quotalen;
	};

Before the preparser is called, the first three fields will have been cleared,
the payload pointer and size will be stored in data and datalen and the default
quota size from the key_type struct will be stored into quotalen.

The preparser may parse the payload in any way it likes and may store data in
the type_data[] and payload fields for use by the instantiate() and update()
ops.

The preparser may also propose a description for the key by attaching it as a
string to the description field.  This can be used by passing a NULL or ""
description to the add_key() system call or the key_create_or_update()
function.  This cannot work with request_key() as that required the description
to tell the upcall about the key to be created.

This, for example permits keys that store PGP public keys to generate their own
name from the user ID and public key fingerprint in the key.

The instantiate() and update() operations are then modified to look like this:

	int (*instantiate)(struct key *key, struct key_preparsed_payload *prep);
	int (*update)(struct key *key, struct key_preparsed_payload *prep);

and the new payload data is passed in *prep, whether or not it was preparsed.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2012-10-08 13:49:48 +10:30
David Howells 4442d7704c Merge branch 'modsign-keys-devel' into security-next-keys
Signed-off-by: David Howells <dhowells@redhat.com>
2012-10-02 19:30:19 +01:00
David Howells f8aa23a55f KEYS: Use keyring_alloc() to create special keyrings
Use keyring_alloc() to create special keyrings now that it has a permissions
parameter rather than using key_alloc() + key_instantiate_and_link().

Also document and export keyring_alloc() so that modules can use it too.

Signed-off-by: David Howells <dhowells@redhat.com>
2012-10-02 19:24:56 +01:00
David Howells 96b5c8fea6 KEYS: Reduce initial permissions on keys
Reduce the initial permissions on new keys to grant the possessor everything,
view permission only to the user (so the keys can be seen in /proc/keys) and
nothing else.

This gives the creator a chance to adjust the permissions mask before other
processes can access the new key or create a link to it.

To aid with this, keyring_alloc() now takes a permission argument rather than
setting the permissions itself.

The following permissions are now set:

 (1) The user and user-session keyrings grant the user that owns them full
     permissions and grant a possessor everything bar SETATTR.

 (2) The process and thread keyrings grant the possessor full permissions but
     only grant the user VIEW.  This permits the user to see them in
     /proc/keys, but not to do anything with them.

 (3) Anonymous session keyrings grant the possessor full permissions, but only
     grant the user VIEW and READ.  This means that the user can see them in
     /proc/keys and can list them, but nothing else.  Possibly READ shouldn't
     be provided either.

 (4) Named session keyrings grant everything an anonymous session keyring does,
     plus they grant the user LINK permission.  The whole point of named
     session keyrings is that others can also subscribe to them.  Possibly this
     should be a separate permission to LINK.

 (5) The temporary session keyring created by call_sbin_request_key() gets the
     same permissions as an anonymous session keyring.

 (6) Keys created by add_key() get VIEW, SEARCH, LINK and SETATTR for the
     possessor, plus READ and/or WRITE if the key type supports them.  The used
     only gets VIEW now.

 (7) Keys created by request_key() now get the same as those created by
     add_key().

Reported-by: Lennart Poettering <lennart@poettering.net>
Reported-by: Stef Walter <stefw@redhat.com>
Signed-off-by: David Howells <dhowells@redhat.com>
2012-10-02 19:24:56 +01:00
Eric W. Biederman 9a56c2db49 userns: Convert security/keys to the new userns infrastructure
- Replace key_user ->user_ns equality checks with kuid_has_mapping checks.
- Use from_kuid to generate key descriptions
- Use kuid_t and kgid_t and the associated helpers instead of uid_t and gid_t
- Avoid potential problems with file descriptor passing by displaying
  keys in the user namespace of the opener of key status proc files.

Cc: linux-security-module@vger.kernel.org
Cc: keyrings@linux-nfs.org
Cc: David Howells <dhowells@redhat.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
2012-09-13 18:28:02 -07:00
David Howells d4f65b5d24 KEYS: Add payload preparsing opportunity prior to key instantiate or update
Give the key type the opportunity to preparse the payload prior to the
instantiation and update routines being called.  This is done with the
provision of two new key type operations:

	int (*preparse)(struct key_preparsed_payload *prep);
	void (*free_preparse)(struct key_preparsed_payload *prep);

If the first operation is present, then it is called before key creation (in
the add/update case) or before the key semaphore is taken (in the update and
instantiate cases).  The second operation is called to clean up if the first
was called.

preparse() is given the opportunity to fill in the following structure:

	struct key_preparsed_payload {
		char		*description;
		void		*type_data[2];
		void		*payload;
		const void	*data;
		size_t		datalen;
		size_t		quotalen;
	};

Before the preparser is called, the first three fields will have been cleared,
the payload pointer and size will be stored in data and datalen and the default
quota size from the key_type struct will be stored into quotalen.

The preparser may parse the payload in any way it likes and may store data in
the type_data[] and payload fields for use by the instantiate() and update()
ops.

The preparser may also propose a description for the key by attaching it as a
string to the description field.  This can be used by passing a NULL or ""
description to the add_key() system call or the key_create_or_update()
function.  This cannot work with request_key() as that required the description
to tell the upcall about the key to be created.

This, for example permits keys that store PGP public keys to generate their own
name from the user ID and public key fingerprint in the key.

The instantiate() and update() operations are then modified to look like this:

	int (*instantiate)(struct key *key, struct key_preparsed_payload *prep);
	int (*update)(struct key *key, struct key_preparsed_payload *prep);

and the new payload data is passed in *prep, whether or not it was preparsed.

Signed-off-by: David Howells <dhowells@redhat.com>
2012-09-13 13:06:29 +01:00
David Howells 423b978802 KEYS: Fix some sparse warnings
Fix some sparse warnings in the keyrings code:

 (1) compat_keyctl_instantiate_key_iov() should be static.

 (2) There were a couple of places where a pointer was being compared against
     integer 0 rather than NULL.

 (3) keyctl_instantiate_key_common() should not take a __user-labelled iovec
     pointer as the caller must have copied the iovec to kernel space.

 (4) __key_link_begin() takes and __key_link_end() releases
     keyring_serialise_link_sem under some circumstances and so this should be
     declared.

     Note that adding __acquires() and __releases() for this doesn't help cure
     the warnings messages - something only commenting out both helps.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>
2012-05-25 20:51:42 +10:00
David Howells fd75815f72 KEYS: Add invalidation support
Add support for invalidating a key - which renders it immediately invisible to
further searches and causes the garbage collector to immediately wake up,
remove it from keyrings and then destroy it when it's no longer referenced.

It's better not to do this with keyctl_revoke() as that marks the key to start
returning -EKEYREVOKED to searches when what is actually desired is to have the
key refetched.

To invalidate a key the caller must be granted SEARCH permission by the key.
This may be too strict.  It may be better to also permit invalidation if the
caller has any of READ, WRITE or SETATTR permission.

The primary use for this is to evict keys that are cached in special keyrings,
such as the DNS resolver or an ID mapper.

Signed-off-by: David Howells <dhowells@redhat.com>
2012-05-11 10:56:56 +01:00
David Howells 31d5a79d7f KEYS: Do LRU discard in full keyrings
Do an LRU discard in keyrings that are full rather than returning ENFILE.  To
perform this, a time_t is added to the key struct and updated by the creation
of a link to a key and by a key being found as the result of a search.  At the
completion of a successful search, the keyrings in the path between the root of
the search and the first found link to it also have their last-used times
updated.

Note that discarding a link to a key from a keyring does not necessarily
destroy the key as there may be references held by other places.

An alternate discard method that might suffice is to perform FIFO discard from
the keyring, using the spare 2-byte hole in the keylist header as the index of
the next link to be discarded.

This is useful when using a keyring as a cache for DNS results or foreign
filesystem IDs.


This can be tested by the following.  As root do:

	echo 1000 >/proc/sys/kernel/keys/root_maxkeys

	kr=`keyctl newring foo @s`
	for ((i=0; i<2000; i++)); do keyctl add user a$i a $kr; done

Without this patch ENFILE should be reported when the keyring fills up.  With
this patch, the keyring discards keys in an LRU fashion.  Note that the stored
LRU time has a granularity of 1s.

After doing this, /proc/key-users can be observed and should show that most of
the 2000 keys have been discarded:

	[root@andromeda ~]# cat /proc/key-users
	    0:   517 516/516 513/1000 5249/20000

The "513/1000" here is the number of quota-accounted keys present for this user
out of the maximum permitted.

In /proc/keys, the keyring shows the number of keys it has and the number of
slots it has allocated:

	[root@andromeda ~]# grep foo /proc/keys
	200c64c4 I--Q--     1 perm 3b3f0000     0     0 keyring   foo: 509/509

The maximum is (PAGE_SIZE - header) / key pointer size.  That's typically 509
on a 64-bit system and 1020 on a 32-bit system.

Signed-off-by: David Howells <dhowells@redhat.com>
2012-05-11 10:56:56 +01:00
David Howells 233e4735f2 KEYS: Permit in-place link replacement in keyring list
Make use of the previous patch that makes the garbage collector perform RCU
synchronisation before destroying defunct keys.  Key pointers can now be
replaced in-place without creating a new keyring payload and replacing the
whole thing as the discarded keys will not be destroyed until all currently
held RCU read locks are released.

If the keyring payload space needs to be expanded or contracted, then a
replacement will still need allocating, and the original will still have to be
freed by RCU.

Signed-off-by: David Howells <dhowells@redhat.com>
2012-05-11 10:56:56 +01:00
David Howells efde8b6e16 KEYS: Add missing smp_rmb() primitives to the keyring search code
Add missing smp_rmb() primitives to the keyring search code.

When keyring payloads are appended to without replacement (thus using up spare
slots in the key pointer array), an smp_wmb() is issued between the pointer
assignment and the increment of the key count (nkeys).

There should be corresponding read barriers between the read of nkeys and
dereferences of keys[n] when n is dependent on the value of nkeys.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
2012-01-18 10:41:27 +11:00
David Howells 6d528b0822 KEYS: __key_link() should use the RCU deref wrapper for keyring payloads
__key_link() should use the RCU deref wrapper rcu_dereference_locked_keyring()
for accessing keyring payloads rather than calling rcu_dereference_protected()
directly.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
2011-08-23 09:57:34 +10:00
Michal Hocko d8bf4ca9ca rcu: treewide: Do not use rcu_read_lock_held when calling rcu_dereference_check
Since ca5ecddf (rcu: define __rcu address space modifier for sparse)
rcu_dereference_check use rcu_read_lock_held as a part of condition
automatically so callers do not have to do that as well.

Signed-off-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2011-07-08 22:21:58 +02:00
David Howells 78b7280cce KEYS: Improve /proc/keys
Improve /proc/keys by:

 (1) Don't attempt to summarise the payload of a negated key.  It won't have
     one.  To this end, a helper function - key_is_instantiated() has been
     added that allows the caller to find out whether the key is positively
     instantiated (as opposed to being uninstantiated or negatively
     instantiated).

 (2) Do show keys that are negative, expired or revoked rather than hiding
     them.  This requires an override flag (no_state_check) to be passed to
     search_my_process_keyrings() and keyring_search_aux() to suppress this
     check.

     Without this, keys that are possessed by the caller, but only grant
     permissions to the caller if possessed are skipped as the possession check
     fails.

     Keys that are visible due to user, group or other checks are visible with
     or without this patch.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
2011-03-17 11:59:32 +11:00
David Howells fdd1b94581 KEYS: Add a new keyctl op to reject a key with a specified error code
Add a new keyctl op to reject a key with a specified error code.  This works
much the same as negating a key, and so keyctl_negate_key() is made a special
case of keyctl_reject_key().  The difference is that keyctl_negate_key()
selects ENOKEY as the error to be reported.

Typically the key would be rejected with EKEYEXPIRED, EKEYREVOKED or
EKEYREJECTED, but this is not mandatory.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
2011-03-08 11:17:18 +11:00
David Howells ceb73c1204 KEYS: Fix __key_link_end() quota fixup on error
Fix __key_link_end()'s attempt to fix up the quota if an error occurs.

There are two erroneous cases: Firstly, we always decrease the quota if
the preallocated replacement keyring needs cleaning up, irrespective of
whether or not we should (we may have replaced a pointer rather than
adding another pointer).

Secondly, we never clean up the quota if we added a pointer without the
keyring storage being extended (we allocate multiple pointers at a time,
even if we're not going to use them all immediately).

We handle this by setting the bottom bit of the preallocation pointer in
__key_link_begin() to indicate that the quota needs fixing up, which is
then passed to __key_link() (which clears the whole thing) and
__key_link_end().

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-26 08:58:20 +10:00
David Howells 973c9f4f49 KEYS: Fix up comments in key management code
Fix up comments in the key management code.  No functional changes.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-21 14:59:30 -08:00
David Howells a8b17ed019 KEYS: Do some style cleanup in the key management code.
Do a bit of a style clean up in the key management code.  No functional
changes.

Done using:

  perl -p -i -e 's!^/[*]*/\n!!' security/keys/*.c
  perl -p -i -e 's!} /[*] end [a-z0-9_]*[(][)] [*]/\n!}\n!' security/keys/*.c
  sed -i -s -e ": next" -e N -e 's/^\n[}]$/}/' -e t -e P -e 's/^.*\n//' -e "b next" security/keys/*.c

To remove /*****/ lines, remove comments on the closing brace of a
function to name the function and remove blank lines before the closing
brace of a function.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-21 14:59:29 -08:00
Alexey Dobriyan 4be929be34 kernel-wide: replace USHORT_MAX, SHORT_MAX and SHORT_MIN with USHRT_MAX, SHRT_MAX and SHRT_MIN
- C99 knows about USHRT_MAX/SHRT_MAX/SHRT_MIN, not
  USHORT_MAX/SHORT_MAX/SHORT_MIN.

- Make SHRT_MIN of type s16, not int, for consistency.

[akpm@linux-foundation.org: fix drivers/dma/timb_dma.c]
[akpm@linux-foundation.org: fix security/keys/keyring.c]
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Acked-by: WANG Cong <xiyou.wangcong@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-25 08:07:02 -07:00
David Howells f70e2e0619 KEYS: Do preallocation for __key_link()
Do preallocation for __key_link() so that the various callers in request_key.c
can deal with any errors from this source before attempting to construct a key.
This allows them to assume that the actual linkage step is guaranteed to be
successful.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
2010-05-06 22:25:02 +10:00
James Morris 043b4d40f5 Merge branch 'master' into next
Conflicts:
	security/keys/keyring.c

Resolved conflict with whitespace fix in find_keyring_by_name()

Signed-off-by: James Morris <jmorris@namei.org>
2010-05-06 22:21:04 +10:00
David Howells 553d603c8f KEYS: keyring_serialise_link_sem is only needed for keyring->keyring links
keyring_serialise_link_sem is only needed for keyring->keyring links as it's
used to prevent cycle detection from being avoided by parallel keyring
additions.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
2010-05-06 10:56:52 +10:00
James Morris 0ffbe2699c Merge branch 'master' into next 2010-05-06 10:56:07 +10:00
David Howells f0641cba77 KEYS: Use RCU dereference wrappers in keyring key type code
The keyring key type code should use RCU dereference wrappers, even when it
holds the keyring's key semaphore.

Reported-by: Vegard Nossum <vegard.nossum@gmail.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
2010-05-05 23:50:12 +10:00
Toshiyuki Okajima cea7daa358 KEYS: find_keyring_by_name() can gain access to a freed keyring
find_keyring_by_name() can gain access to a keyring that has had its reference
count reduced to zero, and is thus ready to be freed.  This then allows the
dead keyring to be brought back into use whilst it is being destroyed.

The following timeline illustrates the process:

|(cleaner)                           (user)
|
| free_user(user)                    sys_keyctl()
|  |                                  |
|  key_put(user->session_keyring)     keyctl_get_keyring_ID()
|  ||	//=> keyring->usage = 0        |
|  |schedule_work(&key_cleanup_task)   lookup_user_key()
|  ||                                   |
|  kmem_cache_free(,user)               |
|  .                                    |[KEY_SPEC_USER_KEYRING]
|  .                                    install_user_keyrings()
|  .                                    ||
| key_cleanup() [<= worker_thread()]    ||
|  |                                    ||
|  [spin_lock(&key_serial_lock)]        |[mutex_lock(&key_user_keyr..mutex)]
|  |                                    ||
|  atomic_read() == 0                   ||
|  |{ rb_ease(&key->serial_node,) }     ||
|  |                                    ||
|  [spin_unlock(&key_serial_lock)]      |find_keyring_by_name()
|  |                                    |||
|  keyring_destroy(keyring)             ||[read_lock(&keyring_name_lock)]
|  ||                                   |||
|  |[write_lock(&keyring_name_lock)]    ||atomic_inc(&keyring->usage)
|  |.                                   ||| *** GET freeing keyring ***
|  |.                                   ||[read_unlock(&keyring_name_lock)]
|  ||                                   ||
|  |list_del()                          |[mutex_unlock(&key_user_k..mutex)]
|  ||                                   |
|  |[write_unlock(&keyring_name_lock)]  ** INVALID keyring is returned **
|  |                                    .
|  kmem_cache_free(,keyring)            .
|                                       .
|                                       atomic_dec(&keyring->usage)
v                                         *** DESTROYED ***
TIME

If CONFIG_SLUB_DEBUG=y then we may see the following message generated:

	=============================================================================
	BUG key_jar: Poison overwritten
	-----------------------------------------------------------------------------

	INFO: 0xffff880197a7e200-0xffff880197a7e200. First byte 0x6a instead of 0x6b
	INFO: Allocated in key_alloc+0x10b/0x35f age=25 cpu=1 pid=5086
	INFO: Freed in key_cleanup+0xd0/0xd5 age=12 cpu=1 pid=10
	INFO: Slab 0xffffea000592cb90 objects=16 used=2 fp=0xffff880197a7e200 flags=0x200000000000c3
	INFO: Object 0xffff880197a7e200 @offset=512 fp=0xffff880197a7e300

	Bytes b4 0xffff880197a7e1f0:  5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a ZZZZZZZZZZZZZZZZ
	  Object 0xffff880197a7e200:  6a 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b jkkkkkkkkkkkkkkk

Alternatively, we may see a system panic happen, such as:

	BUG: unable to handle kernel NULL pointer dereference at 0000000000000001
	IP: [<ffffffff810e61a3>] kmem_cache_alloc+0x5b/0xe9
	PGD 6b2b4067 PUD 6a80d067 PMD 0
	Oops: 0000 [#1] SMP
	last sysfs file: /sys/kernel/kexec_crash_loaded
	CPU 1
	...
	Pid: 31245, comm: su Not tainted 2.6.34-rc5-nofixed-nodebug #2 D2089/PRIMERGY
	RIP: 0010:[<ffffffff810e61a3>]  [<ffffffff810e61a3>] kmem_cache_alloc+0x5b/0xe9
	RSP: 0018:ffff88006af3bd98  EFLAGS: 00010002
	RAX: 0000000000000000 RBX: 0000000000000001 RCX: ffff88007d19900b
	RDX: 0000000100000000 RSI: 00000000000080d0 RDI: ffffffff81828430
	RBP: ffffffff81828430 R08: ffff88000a293750 R09: 0000000000000000
	R10: 0000000000000001 R11: 0000000000100000 R12: 00000000000080d0
	R13: 00000000000080d0 R14: 0000000000000296 R15: ffffffff810f20ce
	FS:  00007f97116bc700(0000) GS:ffff88000a280000(0000) knlGS:0000000000000000
	CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
	CR2: 0000000000000001 CR3: 000000006a91c000 CR4: 00000000000006e0
	DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
	DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
	Process su (pid: 31245, threadinfo ffff88006af3a000, task ffff8800374414c0)
	Stack:
	 0000000512e0958e 0000000000008000 ffff880037f8d180 0000000000000001
	 0000000000000000 0000000000008001 ffff88007d199000 ffffffff810f20ce
	 0000000000008000 ffff88006af3be48 0000000000000024 ffffffff810face3
	Call Trace:
	 [<ffffffff810f20ce>] ? get_empty_filp+0x70/0x12f
	 [<ffffffff810face3>] ? do_filp_open+0x145/0x590
	 [<ffffffff810ce208>] ? tlb_finish_mmu+0x2a/0x33
	 [<ffffffff810ce43c>] ? unmap_region+0xd3/0xe2
	 [<ffffffff810e4393>] ? virt_to_head_page+0x9/0x2d
	 [<ffffffff81103916>] ? alloc_fd+0x69/0x10e
	 [<ffffffff810ef4ed>] ? do_sys_open+0x56/0xfc
	 [<ffffffff81008a02>] ? system_call_fastpath+0x16/0x1b
	Code: 0f 1f 44 00 00 49 89 c6 fa 66 0f 1f 44 00 00 65 4c 8b 04 25 60 e8 00 00 48 8b 45 00 49 01 c0 49 8b 18 48 85 db 74 0d 48 63 45 18 <48> 8b 04 03 49 89 00 eb 14 4c 89 f9 83 ca ff 44 89 e6 48 89 ef
	RIP  [<ffffffff810e61a3>] kmem_cache_alloc+0x5b/0xe9

This problem is that find_keyring_by_name does not confirm that the keyring is
valid before accepting it.

Skipping keyrings that have been reduced to a zero count seems the way to go.
To this end, use atomic_inc_not_zero() to increment the usage count and skip
the candidate keyring if that returns false.

The following script _may_ cause the bug to happen, but there's no guarantee
as the window of opportunity is small:

	#!/bin/sh
	LOOP=100000
	USER=dummy_user
	/bin/su -c "exit;" $USER || { /usr/sbin/adduser -m $USER; add=1; }
	for ((i=0; i<LOOP; i++))
	do
		/bin/su -c "echo '$i' > /dev/null" $USER
	done
	(( add == 1 )) && /usr/sbin/userdel -r $USER
	exit

Note that the nominated user must not be in use.

An alternative way of testing this may be:

	for ((i=0; i<100000; i++))
	do
		keyctl session foo /bin/true || break
	done >&/dev/null

as that uses a keyring named "foo" rather than relying on the user and
user-session named keyrings.

Reported-by: Toshiyuki Okajima <toshi.okajima@jp.fujitsu.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: Toshiyuki Okajima <toshi.okajima@jp.fujitsu.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
2010-05-05 23:49:10 +10:00
David Howells b59ec78cdc keys: don't need to use RCU in keyring_read() as semaphore is held
keyring_read() doesn't need to use rcu_dereference() to access the keyring
payload as the caller holds the key semaphore to prevent modifications
from happening whilst the data is read out.

This should solve the following warning:

===================================================
[ INFO: suspicious rcu_dereference_check() usage. ]
---------------------------------------------------
security/keys/keyring.c:204 invoked rcu_dereference_check() without protection!

other info that might help us debug this:

rcu_scheduler_active = 1, debug_locks = 0
1 lock held by keyctl/2144:
 #0:  (&key->sem){+++++.}, at: [<ffffffff81177f7c>] keyctl_read_key+0x9c/0xcf

stack backtrace:
Pid: 2144, comm: keyctl Not tainted 2.6.34-rc2-cachefs #113
Call Trace:
 [<ffffffff8105121f>] lockdep_rcu_dereference+0xaa/0xb2
 [<ffffffff811762d5>] keyring_read+0x4d/0xe7
 [<ffffffff81177f8c>] keyctl_read_key+0xac/0xcf
 [<ffffffff811788d4>] sys_keyctl+0x75/0xb9
 [<ffffffff81001eeb>] system_call_fastpath+0x16/0x1b

Signed-off-by: David Howells <dhowells@redhat.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: James Morris <jmorris@namei.org>
2010-04-28 08:37:15 +10:00
Justin P. Mattock c5b60b5e67 security: whitespace coding style fixes
Whitespace coding style fixes.

Signed-off-by: Justin P. Mattock <justinmattock@gmail.com>
Signed-off-by: James Morris <jmorris@namei.org>
2010-04-23 10:10:23 +10:00
Chihau Chau 512ea3bc30 Security: key: keyring: fix some code style issues
This fixes to include <linux/uaccess.h> instead <asm/uaccess.h> and some
code style issues like to put a else sentence below close brace '}' and
to replace a tab instead of some space characters.

Signed-off-by: Chihau Chau <chihau@gmail.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
2010-03-10 08:46:15 +11:00
wzt.wzt@gmail.com c8563473c1 Security: Fix some coding styles in security/keys/keyring.c
Fix some coding styles in security/keys/keyring.c

Signed-off-by: Zhitong Wang <zhitong.wangzt@alibaba-inc.com>
Signed-off-by: James Morris <jmorris@namei.org>
2010-03-05 09:49:02 +11:00
Paul E. McKenney e7b0a61b79 security: Apply lockdep-based checking to rcu_dereference() uses
Apply lockdep-ified RCU primitives to key_gc_keyring() and
keyring_destroy().

Cc: David Howells <dhowells@redhat.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: laijs@cn.fujitsu.com
Cc: dipankar@in.ibm.com
Cc: mathieu.desnoyers@polymtl.ca
Cc: josh@joshtriplett.org
Cc: dvhltc@us.ibm.com
Cc: niv@us.ibm.com
Cc: peterz@infradead.org
Cc: rostedt@goodmis.org
Cc: Valdis.Kletnieks@vt.edu
Cc: dhowells@redhat.com
LKML-Reference: <1266887105-1528-12-git-send-email-paulmck@linux.vnet.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-02-25 10:34:52 +01:00
David Howells c08ef808ef KEYS: Fix garbage collector
Fix a number of problems with the new key garbage collector:

 (1) A rogue semicolon in keyring_gc() was causing the initial count of dead
     keys to be miscalculated.

 (2) A missing return in keyring_gc() meant that under certain circumstances,
     the keyring semaphore would be unlocked twice.

 (3) The key serial tree iterator (key_garbage_collector()) part of the garbage
     collector has been modified to:

     (a) Complete each scan of the keyrings before setting the new timer.

     (b) Only set the new timer for keys that have yet to expire.  This means
         that the new timer is now calculated correctly, and the gc doesn't
         get into a loop continually scanning for keys that have expired, and
         preventing other things from happening, like RCU cleaning up the old
         keyring contents.

     (c) Perform an extra scan if any keys were garbage collected in this one
     	 as a key might become garbage during a scan, and (b) could mean we
     	 don't set the timer again.

 (4) Made key_schedule_gc() take the time at which to do a collection run,
     rather than the time at which the key expires.  This means the collection
     of dead keys (key type unregistered) can happen immediately.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
2009-09-15 09:11:02 +10:00
David Howells 5d135440fa KEYS: Add garbage collection for dead, revoked and expired keys. [try #6]
Add garbage collection for dead, revoked and expired keys.  This involved
erasing all links to such keys from keyrings that point to them.  At that
point, the key will be deleted in the normal manner.

Keyrings from which garbage collection occurs are shrunk and their quota
consumption reduced as appropriate.

Dead keys (for which the key type has been removed) will be garbage collected
immediately.

Revoked and expired keys will hang around for a number of seconds, as set in
/proc/sys/kernel/keys/gc_delay before being automatically removed.  The default
is 5 minutes.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
2009-09-02 21:29:11 +10:00
Serge E. Hallyn 2ea190d0a0 keys: skip keys from another user namespace
When listing keys, do not return keys belonging to the
same uid in another user namespace.  Otherwise uid 500
in another user namespace will return keyrings called
uid.500 for another user namespace.

Signed-off-by: Serge E. Hallyn <serue@us.ibm.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
2009-02-27 12:35:12 +11:00
David Howells d84f4f992c CRED: Inaugurate COW credentials
Inaugurate copy-on-write credentials management.  This uses RCU to manage the
credentials pointer in the task_struct with respect to accesses by other tasks.
A process may only modify its own credentials, and so does not need locking to
access or modify its own credentials.

A mutex (cred_replace_mutex) is added to the task_struct to control the effect
of PTRACE_ATTACHED on credential calculations, particularly with respect to
execve().

With this patch, the contents of an active credentials struct may not be
changed directly; rather a new set of credentials must be prepared, modified
and committed using something like the following sequence of events:

	struct cred *new = prepare_creds();
	int ret = blah(new);
	if (ret < 0) {
		abort_creds(new);
		return ret;
	}
	return commit_creds(new);

There are some exceptions to this rule: the keyrings pointed to by the active
credentials may be instantiated - keyrings violate the COW rule as managing
COW keyrings is tricky, given that it is possible for a task to directly alter
the keys in a keyring in use by another task.

To help enforce this, various pointers to sets of credentials, such as those in
the task_struct, are declared const.  The purpose of this is compile-time
discouragement of altering credentials through those pointers.  Once a set of
credentials has been made public through one of these pointers, it may not be
modified, except under special circumstances:

  (1) Its reference count may incremented and decremented.

  (2) The keyrings to which it points may be modified, but not replaced.

The only safe way to modify anything else is to create a replacement and commit
using the functions described in Documentation/credentials.txt (which will be
added by a later patch).

This patch and the preceding patches have been tested with the LTP SELinux
testsuite.

This patch makes several logical sets of alteration:

 (1) execve().

     This now prepares and commits credentials in various places in the
     security code rather than altering the current creds directly.

 (2) Temporary credential overrides.

     do_coredump() and sys_faccessat() now prepare their own credentials and
     temporarily override the ones currently on the acting thread, whilst
     preventing interference from other threads by holding cred_replace_mutex
     on the thread being dumped.

     This will be replaced in a future patch by something that hands down the
     credentials directly to the functions being called, rather than altering
     the task's objective credentials.

 (3) LSM interface.

     A number of functions have been changed, added or removed:

     (*) security_capset_check(), ->capset_check()
     (*) security_capset_set(), ->capset_set()

     	 Removed in favour of security_capset().

     (*) security_capset(), ->capset()

     	 New.  This is passed a pointer to the new creds, a pointer to the old
     	 creds and the proposed capability sets.  It should fill in the new
     	 creds or return an error.  All pointers, barring the pointer to the
     	 new creds, are now const.

     (*) security_bprm_apply_creds(), ->bprm_apply_creds()

     	 Changed; now returns a value, which will cause the process to be
     	 killed if it's an error.

     (*) security_task_alloc(), ->task_alloc_security()

     	 Removed in favour of security_prepare_creds().

     (*) security_cred_free(), ->cred_free()

     	 New.  Free security data attached to cred->security.

     (*) security_prepare_creds(), ->cred_prepare()

     	 New. Duplicate any security data attached to cred->security.

     (*) security_commit_creds(), ->cred_commit()

     	 New. Apply any security effects for the upcoming installation of new
     	 security by commit_creds().

     (*) security_task_post_setuid(), ->task_post_setuid()

     	 Removed in favour of security_task_fix_setuid().

     (*) security_task_fix_setuid(), ->task_fix_setuid()

     	 Fix up the proposed new credentials for setuid().  This is used by
     	 cap_set_fix_setuid() to implicitly adjust capabilities in line with
     	 setuid() changes.  Changes are made to the new credentials, rather
     	 than the task itself as in security_task_post_setuid().

     (*) security_task_reparent_to_init(), ->task_reparent_to_init()

     	 Removed.  Instead the task being reparented to init is referred
     	 directly to init's credentials.

	 NOTE!  This results in the loss of some state: SELinux's osid no
	 longer records the sid of the thread that forked it.

     (*) security_key_alloc(), ->key_alloc()
     (*) security_key_permission(), ->key_permission()

     	 Changed.  These now take cred pointers rather than task pointers to
     	 refer to the security context.

 (4) sys_capset().

     This has been simplified and uses less locking.  The LSM functions it
     calls have been merged.

 (5) reparent_to_kthreadd().

     This gives the current thread the same credentials as init by simply using
     commit_thread() to point that way.

 (6) __sigqueue_alloc() and switch_uid()

     __sigqueue_alloc() can't stop the target task from changing its creds
     beneath it, so this function gets a reference to the currently applicable
     user_struct which it then passes into the sigqueue struct it returns if
     successful.

     switch_uid() is now called from commit_creds(), and possibly should be
     folded into that.  commit_creds() should take care of protecting
     __sigqueue_alloc().

 (7) [sg]et[ug]id() and co and [sg]et_current_groups.

     The set functions now all use prepare_creds(), commit_creds() and
     abort_creds() to build and check a new set of credentials before applying
     it.

     security_task_set[ug]id() is called inside the prepared section.  This
     guarantees that nothing else will affect the creds until we've finished.

     The calling of set_dumpable() has been moved into commit_creds().

     Much of the functionality of set_user() has been moved into
     commit_creds().

     The get functions all simply access the data directly.

 (8) security_task_prctl() and cap_task_prctl().

     security_task_prctl() has been modified to return -ENOSYS if it doesn't
     want to handle a function, or otherwise return the return value directly
     rather than through an argument.

     Additionally, cap_task_prctl() now prepares a new set of credentials, even
     if it doesn't end up using it.

 (9) Keyrings.

     A number of changes have been made to the keyrings code:

     (a) switch_uid_keyring(), copy_keys(), exit_keys() and suid_keys() have
     	 all been dropped and built in to the credentials functions directly.
     	 They may want separating out again later.

     (b) key_alloc() and search_process_keyrings() now take a cred pointer
     	 rather than a task pointer to specify the security context.

     (c) copy_creds() gives a new thread within the same thread group a new
     	 thread keyring if its parent had one, otherwise it discards the thread
     	 keyring.

     (d) The authorisation key now points directly to the credentials to extend
     	 the search into rather pointing to the task that carries them.

     (e) Installing thread, process or session keyrings causes a new set of
     	 credentials to be created, even though it's not strictly necessary for
     	 process or session keyrings (they're shared).

(10) Usermode helper.

     The usermode helper code now carries a cred struct pointer in its
     subprocess_info struct instead of a new session keyring pointer.  This set
     of credentials is derived from init_cred and installed on the new process
     after it has been cloned.

     call_usermodehelper_setup() allocates the new credentials and
     call_usermodehelper_freeinfo() discards them if they haven't been used.  A
     special cred function (prepare_usermodeinfo_creds()) is provided
     specifically for call_usermodehelper_setup() to call.

     call_usermodehelper_setkeys() adjusts the credentials to sport the
     supplied keyring as the new session keyring.

(11) SELinux.

     SELinux has a number of changes, in addition to those to support the LSM
     interface changes mentioned above:

     (a) selinux_setprocattr() no longer does its check for whether the
     	 current ptracer can access processes with the new SID inside the lock
     	 that covers getting the ptracer's SID.  Whilst this lock ensures that
     	 the check is done with the ptracer pinned, the result is only valid
     	 until the lock is released, so there's no point doing it inside the
     	 lock.

(12) is_single_threaded().

     This function has been extracted from selinux_setprocattr() and put into
     a file of its own in the lib/ directory as join_session_keyring() now
     wants to use it too.

     The code in SELinux just checked to see whether a task shared mm_structs
     with other tasks (CLONE_VM), but that isn't good enough.  We really want
     to know if they're part of the same thread group (CLONE_THREAD).

(13) nfsd.

     The NFS server daemon now has to use the COW credentials to set the
     credentials it is going to use.  It really needs to pass the credentials
     down to the functions it calls, but it can't do that until other patches
     in this series have been applied.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-14 10:39:23 +11:00
David Howells e9e349b051 KEYS: Disperse linux/key_ui.h
Disperse the bits of linux/key_ui.h as the reason they were put here (keyfs)
didn't get in.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: James Morris <jmorris@namei.org>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-14 10:39:13 +11:00
David Howells 69664cf16a keys: don't generate user and user session keyrings unless they're accessed
Don't generate the per-UID user and user session keyrings unless they're
explicitly accessed.  This solves a problem during a login process whereby
set*uid() is called before the SELinux PAM module, resulting in the per-UID
keyrings having the wrong security labels.

This also cures the problem of multiple per-UID keyrings sometimes appearing
due to PAM modules (including pam_keyinit) setuiding and causing user_structs
to come into and go out of existence whilst the session keyring pins the user
keyring.  This is achieved by first searching for extant per-UID keyrings
before inventing new ones.

The serial bound argument is also dropped from find_keyring_by_name() as it's
not currently made use of (setting it to 0 disables the feature).

Signed-off-by: David Howells <dhowells@redhat.com>
Cc: <kwc@citi.umich.edu>
Cc: <arunsr@cse.iitk.ac.in>
Cc: <dwalsh@redhat.com>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: James Morris <jmorris@namei.org>
Cc: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-29 08:06:17 -07:00
Kevin Coffman dceba99441 keys: check starting keyring as part of search
Check the starting keyring as part of the search to (a) see if that is what
we're searching for, and (b) to check it is still valid for searching.

The scenario: User in process A does things that cause things to be created in
its process session keyring.  The user then does an su to another user and
starts a new process, B.  The two processes now share the same process session
keyring.

Process B does an NFS access which results in an upcall to gssd.  When gssd
attempts to instantiate the context key (to be linked into the process session
keyring), it is denied access even though it has an authorization key.

The order of calls is:

   keyctl_instantiate_key()
      lookup_user_key()				    (the default: case)
         search_process_keyrings(current)
	    search_process_keyrings(rka->context)   (recursive call)
	       keyring_search_aux()

keyring_search_aux() verifies the keys and keyrings underneath the top-level
keyring it is given, but that top-level keyring is neither fully validated nor
checked to see if it is the thing being searched for.

This patch changes keyring_search_aux() to:
1) do more validation on the top keyring it is given and
2) check whether that top-level keyring is the thing being searched for

Signed-off-by: Kevin Coffman <kwc@citi.umich.edu>
Signed-off-by: David Howells <dhowells@redhat.com>
Cc: Paul Moore <paul.moore@hp.com>
Cc: Chris Wright <chrisw@sous-sol.org>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: James Morris <jmorris@namei.org>
Cc: Kevin Coffman <kwc@citi.umich.edu>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-29 08:06:16 -07:00
David Howells 7318226ea2 [AF_RXRPC]: Key facility changes for AF_RXRPC
Export the keyring key type definition and document its availability.

Add alternative types into the key's type_data union to make it more useful.
Not all users necessarily want to use it as a list_head (AF_RXRPC doesn't, for
example), so make it clear that it can be used in other ways.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-26 15:46:23 -07:00
Eric Sesterhenn 48ad504ee7 [PATCH] security/keys/*: user kmemdup()
Signed-off-by: Eric Sesterhenn <snakebyte@gmx.de>
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Acked-By: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-07 08:39:25 -08:00
David Howells 31204ed925 [PATCH] keys: discard the contents of a key on revocation
Cause the keys linked to a keyring to be unlinked from it when revoked and it
causes the data attached to a user-defined key to be discarded when revoked.

This frees up most of the quota a key occupied at that point, rather than
waiting for the key to actually be destroyed.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-26 09:58:18 -07:00
David Howells 7e047ef5fe [PATCH] keys: sort out key quota system
Add the ability for key creation to overrun the user's quota in some
circumstances - notably when a session keyring is created and assigned to a
process that didn't previously have one.

This means it's still possible to log in, should PAM require the creation of a
new session keyring, and fix an overburdened key quota.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-26 09:58:18 -07:00
Michael LeMay d720024e94 [PATCH] selinux: add hooks for key subsystem
Introduce SELinux hooks to support the access key retention subsystem
within the kernel.  Incorporate new flask headers from a modified version
of the SELinux reference policy, with support for the new security class
representing retained keys.  Extend the "key_alloc" security hook with a
task parameter representing the intended ownership context for the key
being allocated.  Attach security information to root's default keyrings
within the SELinux initialization routine.

Has passed David's testsuite.

Signed-off-by: Michael LeMay <mdlemay@epoch.ncsc.mil>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
Acked-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-22 15:05:55 -07:00
David Howells c3a9d6541f [Security] Keys: Fix oops when adding key to non-keyring
This fixes the problem of an oops occuring when a user attempts to add a
key to a non-keyring key [CVE-2006-1522].

The problem is that __keyring_search_one() doesn't check that the
keyring it's been given is actually a keyring.

I've fixed this problem by:

 (1) declaring that caller of __keyring_search_one() must guarantee that
     the keyring is a keyring; and

 (2) making key_create_or_update() check that the keyring is a keyring,
     and return -ENOTDIR if it isn't.

This can be tested by:

	keyctl add user b b `keyctl add user a a @s`

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-04-10 09:33:46 -07:00
David Howells b5f545c880 [PATCH] keys: Permit running process to instantiate keys
Make it possible for a running process (such as gssapid) to be able to
instantiate a key, as was requested by Trond Myklebust for NFS4.

The patch makes the following changes:

 (1) A new, optional key type method has been added. This permits a key type
     to intercept requests at the point /sbin/request-key is about to be
     spawned and do something else with them - passing them over the
     rpc_pipefs files or netlink sockets for instance.

     The uninstantiated key, the authorisation key and the intended operation
     name are passed to the method.

 (2) The callout_info is no longer passed as an argument to /sbin/request-key
     to prevent unauthorised viewing of this data using ps or by looking in
     /proc/pid/cmdline.

     This means that the old /sbin/request-key program will not work with the
     patched kernel as it will expect to see an extra argument that is no
     longer there.

     A revised keyutils package will be made available tomorrow.

 (3) The callout_info is now attached to the authorisation key. Reading this
     key will retrieve the information.

 (4) A new field has been added to the task_struct. This holds the
     authorisation key currently active for a thread. Searches now look here
     for the caller's set of keys rather than looking for an auth key in the
     lowest level of the session keyring.

     This permits a thread to be servicing multiple requests at once and to
     switch between them. Note that this is per-thread, not per-process, and
     so is usable in multithreaded programs.

     The setting of this field is inherited across fork and exec.

 (5) A new keyctl function (KEYCTL_ASSUME_AUTHORITY) has been added that
     permits a thread to assume the authority to deal with an uninstantiated
     key. Assumption is only permitted if the authorisation key associated
     with the uninstantiated key is somewhere in the thread's keyrings.

     This function can also clear the assumption.

 (6) A new magic key specifier has been added to refer to the currently
     assumed authorisation key (KEY_SPEC_REQKEY_AUTH_KEY).

 (7) Instantiation will only proceed if the appropriate authorisation key is
     assumed first. The assumed authorisation key is discarded if
     instantiation is successful.

 (8) key_validate() is moved from the file of request_key functions to the
     file of permissions functions.

 (9) The documentation is updated.

From: <Valdis.Kletnieks@vt.edu>

    Build fix.

Signed-off-by: David Howells <dhowells@redhat.com>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Cc: Alexander Zangerl <az@bond.edu.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-08 20:13:53 -08:00
David Howells cab8eb594e [PATCH] keys: Discard duplicate keys from a keyring on link
Cause any links within a keyring to keys that match a key to be linked into
that keyring to be discarded as a link to the new key is added.  The match is
contingent on the type and description strings being the same.

This permits requests, adds and searches to displace negative, expired,
revoked and dead keys easily.  After some discussion it was concluded that
duplicate valid keys should probably be discarded also as they would otherwise
hide the new key.

Since request_key() is intended to be the primary method by which keys are
added to a keyring, duplicate valid keys wouldn't be an issue there as that
function would return an existing match in preference to creating a new key.

Signed-off-by: David Howells <dhowells@redhat.com>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Cc: Alexander Zangerl <az@bond.edu.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-08 20:13:53 -08:00
Adrian Bunk 1ae8f40767 [PATCH] security/: possible cleanups
make needlessly global code static

Signed-off-by: Adrian Bunk <bunk@stusta.de>
Cc: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-06 08:33:30 -08:00
David Howells 8d9067bda9 [PATCH] Keys: Remove key duplication
Remove the key duplication stuff since there's nothing that uses it, no way
to get at it and it's awkward to deal with for LSM purposes.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-06 08:33:29 -08:00
David Howells db1d1d57e9 [PATCH] Keys: Fix permissions check for update vs add
Permit add_key() to once again update a matching key rather than adding a
new one if a matching key already exists in the target keyring.

This bug causes add_key() to always add a new key, displacing the old from
the target keyring.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-12-01 15:48:56 -08:00