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| * keys: don't need to use RCU in keyring_read() as semaphore is heldDavid Howells2010-04-281-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* | security: whitespace coding style fixesJustin P. Mattock2010-04-231-10/+10
| | | | | | | | | | | | | | Whitespace coding style fixes. Signed-off-by: Justin P. Mattock <justinmattock@gmail.com> Signed-off-by: James Morris <jmorris@namei.org>
* | Security: key: keyring: fix some code style issuesChihau Chau2010-03-101-4/+3
| | | | | | | | | | | | | | | | | | | | 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>
* | Security: Fix some coding styles in security/keys/keyring.cwzt.wzt@gmail.com2010-03-051-4/+2
|/ | | | | | | 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>
* security: Apply lockdep-based checking to rcu_dereference() usesPaul E. McKenney2010-02-251-1/+3
| | | | | | | | | | | | | | | | | | | | 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>
* KEYS: Fix garbage collectorDavid Howells2009-09-151-5/+19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* KEYS: Add garbage collection for dead, revoked and expired keys. [try #6]David Howells2009-09-021-0/+85
| | | | | | | | | | | | | | | | | | | 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>
* keys: skip keys from another user namespaceSerge E. Hallyn2009-02-271-0/+3
| | | | | | | | | | | 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>
* CRED: Inaugurate COW credentialsDavid Howells2008-11-141-7/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* KEYS: Disperse linux/key_ui.hDavid Howells2008-11-141-0/+1
| | | | | | | | | 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>
* keys: don't generate user and user session keyrings unless they're accessedDavid Howells2008-04-291-12/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* keys: check starting keyring as part of searchKevin Coffman2008-04-291-4/+31
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* [AF_RXRPC]: Key facility changes for AF_RXRPCDavid Howells2007-04-261-0/+2
| | | | | | | | | | | 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>
* [PATCH] security/keys/*: user kmemdup()Eric Sesterhenn2006-12-071-3/+1
| | | | | | | | 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>
* [PATCH] keys: discard the contents of a key on revocationDavid Howells2006-06-261-0/+21
| | | | | | | | | | | | 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>
* [PATCH] keys: sort out key quota systemDavid Howells2006-06-261-2/+2
| | | | | | | | | | | | | 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>
* [PATCH] selinux: add hooks for key subsystemMichael LeMay2006-06-221-2/+3
| | | | | | | | | | | | | | | | | | | 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>
* [Security] Keys: Fix oops when adding key to non-keyringDavid Howells2006-04-101-0/+1
| | | | | | | | | | | | | | | | | | | | | | | 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>
* [PATCH] keys: Permit running process to instantiate keysDavid Howells2006-01-081-45/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* [PATCH] keys: Discard duplicate keys from a keyring on linkDavid Howells2006-01-081-23/+64
| | | | | | | | | | | | | | | | | | | | | 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>
* [PATCH] security/: possible cleanupsAdrian Bunk2006-01-061-1/+1
| | | | | | | | | 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>
* [PATCH] Keys: Remove key duplicationDavid Howells2006-01-061-64/+0
| | | | | | | | | 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>
* [PATCH] Keys: Fix permissions check for update vs addDavid Howells2005-12-011-1/+1
| | | | | | | | | | | | 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>
* [PATCH] Keys: Remove incorrect and obsolete '!' operatorsDavid Howells2005-11-071-4/+4
| | | | | | | | | | The attached patch removes a couple of incorrect and obsolete '!' operators left over from the conversion of the key permission functions from true/false returns to zero/error returns. Signed-Off-By: David Howells <dhowells@redhat.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] Keys: Add LSM hooks for key management [try #3]David Howells2005-10-301-8/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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 <dhowells@redhat.com> Signed-off-by: Chris Wright <chrisw@osdl.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] Keys: Add possessor permissions to keys [try #3]David Howells2005-09-281-36/+50
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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 <dhowells@redhat.com> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] Destruction of failed keyring oopsesDavid Howells2005-08-041-1/+5
| | | | | | | | | | | | | | | | | | | | | | | | | The attached patch makes sure that a keyring that failed to instantiate properly is destroyed without oopsing [CAN-2005-2099]. The problem occurs in three stages: (1) The key allocator initialises the type-specific data to all zeroes. In the case of a keyring, this will become a link in the keyring name list when the keyring is instantiated. (2) If a user (any user) attempts to add a keyring with anything other than an empty payload, the keyring instantiation function will fail with an error and won't add the keyring to the name list. (3) The keyring's destructor then sees that the keyring has a description (name) and tries to remove the keyring from the name list, which oopses because the link pointers are both zero. This bug permits any user to take down a box trivially. Signed-Off-By: David Howells <dhowells@redhat.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] Keys: Base keyring size on key pointer not key structDavid Howells2005-07-071-7/+8
| | | | | | | | | | The attached patch makes the keyring functions calculate the new size of a keyring's payload based on the size of pointer to the key struct, not the size of the key struct itself. Signed-Off-By: David Howells <dhowells@redhat.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] Keys: Make request-key create an authorisation keyDavid Howells2005-06-241-8/+59
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The attached patch makes the following changes: (1) There's a new special key type called ".request_key_auth". This is an authorisation key for when one process requests a key and another process is started to construct it. This type of key cannot be created by the user; nor can it be requested by kernel services. Authorisation keys hold two references: (a) Each refers to a key being constructed. When the key being constructed is instantiated the authorisation key is revoked, rendering it of no further use. (b) The "authorising process". This is either: (i) the process that called request_key(), or: (ii) if the process that called request_key() itself had an authorisation key in its session keyring, then the authorising process referred to by that authorisation key will also be referred to by the new authorisation key. This means that the process that initiated a chain of key requests will authorise the lot of them, and will, by default, wind up with the keys obtained from them in its keyrings. (2) request_key() creates an authorisation key which is then passed to /sbin/request-key in as part of a new session keyring. (3) When request_key() is searching for a key to hand back to the caller, if it comes across an authorisation key in the session keyring of the calling process, it will also search the keyrings of the process specified therein and it will use the specified process's credentials (fsuid, fsgid, groups) to do that rather than the calling process's credentials. This allows a process started by /sbin/request-key to find keys belonging to the authorising process. (4) A key can be read, even if the process executing KEYCTL_READ doesn't have direct read or search permission if that key is contained within the keyrings of a process specified by an authorisation key found within the calling process's session keyring, and is searchable using the credentials of the authorising process. This allows a process started by /sbin/request-key to read keys belonging to the authorising process. (5) The magic KEY_SPEC_*_KEYRING key IDs when passed to KEYCTL_INSTANTIATE or KEYCTL_NEGATE will specify a keyring of the authorising process, rather than the process doing the instantiation. (6) One of the process keyrings can be nominated as the default to which request_key() should attach new keys if not otherwise specified. This is done with KEYCTL_SET_REQKEY_KEYRING and one of the KEY_REQKEY_DEFL_* constants. The current setting can also be read using this call. (7) request_key() is partially interruptible. If it is waiting for another process to finish constructing a key, it can be interrupted. This permits a request-key cycle to be broken without recourse to rebooting. Signed-Off-By: David Howells <dhowells@redhat.com> Signed-Off-By: Benoit Boissinot <benoit.boissinot@ens-lyon.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] keys: Discard key spinlock and use RCU for key payloadDavid Howells2005-06-241-97/+148
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The attached patch changes the key implementation in a number of ways: (1) It removes the spinlock from the key structure. (2) The key flags are now accessed using atomic bitops instead of write-locking the key spinlock and using C bitwise operators. The three instantiation flags are dealt with with the construction semaphore held during the request_key/instantiate/negate sequence, thus rendering the spinlock superfluous. The key flags are also now bit numbers not bit masks. (3) The key payload is now accessed using RCU. This permits the recursive keyring search algorithm to be simplified greatly since no locks need be taken other than the usual RCU preemption disablement. Searching now does not require any locks or semaphores to be held; merely that the starting keyring be pinned. (4) The keyring payload now includes an RCU head so that it can be disposed of by call_rcu(). This requires that the payload be copied on unlink to prevent introducing races in copy-down vs search-up. (5) The user key payload is now a structure with the data following it. It includes an RCU head like the keyring payload and for the same reason. It also contains a data length because the data length in the key may be changed on another CPU whilst an RCU protected read is in progress on the payload. This would then see the supposed RCU payload and the on-key data length getting out of sync. I'm tempted to drop the key's datalen entirely, except that it's used in conjunction with quota management and so is a little tricky to get rid of. (6) Update the keys documentation. Signed-Off-By: David Howells <dhowells@redhat.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* Linux-2.6.12-rc2Linus Torvalds2005-04-161-0/+895
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
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