kernel/linux.git/security/keys/process_keys.c, branch linux-2.6.18.y

[PATCH] keys: sort out key quota system

2006-06-26T16:58:18+00:00

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 Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

[PATCH] Keys: Fix race between two instantiators of a key

2006-06-22T22:05:56+00:00

Add a revocation notification method to the key type and calls it whilst the key's semaphore is still write-locked after setting the revocation flag. The patch then uses this to maintain a reference on the task_struct of the process that calls request_key() for as long as the authorisation key remains unrevoked. This fixes a potential race between two processes both of which have assumed the authority to instantiate a key (one may have forked the other for example). The problem is that there's no locking around the check for revocation of the auth key and the use of the task_struct it points to, nor does the auth key keep a reference on the task_struct. Access to the "context" pointer in the auth key must thenceforth be done with the auth key semaphore held. The revocation method is called with the target key semaphore held write-locked and the search of the context process's keyrings is done with the auth key semaphore read-locked. The check for the revocation state of the auth key just prior to searching it is done after the auth key is read-locked for the search. This ensures that the auth key can't be revoked between the check and the search. The revocation notification method is added so that the context task_struct can be released as soon as instantiation happens rather than waiting for the auth key to be destroyed, thus avoiding the unnecessary pinning of the requesting process. Signed-off-by: David Howells Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

[PATCH] selinux: add hooks for key subsystem

2006-06-22T22:05:55+00:00

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 Signed-off-by: David Howells Signed-off-by: James Morris Acked-by: Chris Wright Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

[PATCH] Keys: Improve usage of memory barriers and remove IRQ disablement

2006-04-11T13:18:45+00:00

Remove an unnecessary memory barrier (implicit in rcu_dereference()) from install_session_keyring(). install_session_keyring() is also rearranged a little to make it slightly more efficient. As install_*_keyring() may schedule (in synchronize_rcu() or keyring_alloc()), they may not be entered with interrupts disabled - and so there's no point saving the interrupt disablement state over the critical section. exec_keys() will also be invoked with interrupts enabled, and so that doesn't need to save the interrupt state either. Signed-off-by: David Howells Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

[PATCH] sem2mutex: security/

2006-03-22T15:54:06+00:00

Semaphore to mutex conversion. The conversion was generated via scripts, and the result was validated automatically via a script as well. Signed-off-by: Ingo Molnar Cc: Stephen Smalley Cc: James Morris Cc: David Howells Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

[PATCH] keys: Permit running process to instantiate keys

2006-01-09T04:13:53+00:00

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: Build fix. Signed-off-by: David Howells Cc: Trond Myklebust Cc: Alexander Zangerl Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

[PATCH] Keys: Add LSM hooks for key management [try #3]

2005-10-31T01:37:23+00:00

The attached patch adds LSM hooks for key management facilities. The notable changes are: (1) The key struct now supports a security pointer for the use of security modules. This will permit key labelling and restrictions on which programs may access a key. (2) Security modules get a chance to note (or abort) the allocation of a key. (3) The key permission checking can now be enhanced by the security modules; the permissions check consults LSM if all other checks bear out. (4) The key permissions checking functions now return an error code rather than a boolean value. (5) An extra permission has been added to govern the modification of attributes (UID, GID, permissions). Note that there isn't an LSM hook specifically for each keyctl() operation, but rather the permissions hook allows control of individual operations based on the permission request bits. Key management access control through LSM is enabled by automatically if both CONFIG_KEYS and CONFIG_SECURITY are enabled. This should be applied on top of the patch ensubjected: [PATCH] Keys: Possessor permissions should be additive Signed-Off-By: David Howells Signed-off-by: Chris Wright Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

[PATCH] Keys: Add possessor permissions to keys [try #3]

2005-09-28T16:10:47+00:00

The attached patch adds extra permission grants to keys for the possessor of a key in addition to the owner, group and other permissions bits. This makes SUID binaries easier to support without going as far as labelling keys and key targets using the LSM facilities. This patch adds a second "pointer type" to key structures (struct key_ref *) that can have the bottom bit of the address set to indicate the possession of a key. This is propagated through searches from the keyring to the discovered key. It has been made a separate type so that the compiler can spot attempts to dereference a potentially incorrect pointer. The "possession" attribute can't be attached to a key structure directly as it's not an intrinsic property of a key. Pointers to keys have been replaced with struct key_ref *'s wherever possession information needs to be passed through. This does assume that the bottom bit of the pointer will always be zero on return from kmem_cache_alloc(). The key reference type has been made into a typedef so that at least it can be located in the sources, even though it's basically a pointer to an undefined type. I've also renamed the accessor functions to be more useful, and all reference variables should now end in "_ref". Signed-Off-By: David Howells Signed-off-by: Linus Torvalds

[PATCH] Error during attempt to join key management session can leave semaphore pinned

2005-08-04T20:11:14+00:00

The attached patch prevents an error during the key session joining operation from hanging future joins in the D state [CAN-2005-2098]. The problem is that the error handling path for the KEYCTL_JOIN_SESSION_KEYRING operation has one error path that doesn't release the session management semaphore. Further attempts to get the semaphore will then sleep for ever in the D state. This can happen in four situations, all involving an attempt to allocate a new session keyring: (1) ENOMEM. (2) The users key quota being reached. (3) A keyring name that is an empty string. (4) A keyring name that is too long. Any user may attempt this operation, and so any user can cause the problem to occur. Signed-Off-By: David Howells Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

[PATCH] RCU: clean up a few remaining synchronize_kernel() calls

2005-06-25T23:24:38+00:00

2.6.12-rc6-mm1 has a few remaining synchronize_kernel()s, some (but not all) in comments. This patch changes these synchronize_kernel() calls (and comments) to synchronize_rcu() or synchronize_sched() as follows: - arch/x86_64/kernel/mce.c mce_read(): change to synchronize_sched() to handle races with machine-check exceptions (synchronize_rcu() would not cut it given RCU implementations intended for hardcore realtime use. - drivers/input/serio/i8042.c i8042_stop(): change to synchronize_sched() to handle races with i8042_interrupt() interrupt handler. Again, synchronize_rcu() would not cut it given RCU implementations intended for hardcore realtime use. - include/*/kdebug.h comments: change to synchronize_sched() to handle races with NMIs. As before, synchronize_rcu() would not cut it... - include/linux/list.h comment: change to synchronize_rcu(), since this comment is for list_del_rcu(). - security/keys/key.c unregister_key_type(): change to synchronize_rcu(), since this is interacting with RCU read side. - security/keys/process_keys.c install_session_keyring(): change to synchronize_rcu(), since this is interacting with RCU read side. Signed-off-by: "Paul E. McKenney" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds