summaryrefslogtreecommitdiff
path: root/security/keys/internal.h
AgeCommit message (Collapse)AuthorFilesLines
2015-04-12switch keyctl_instantiate_key_common() to iov_iterAl Viro1-2/+3
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2014-12-02KEYS: request_key() should reget expired keys rather than give EKEYEXPIREDDavid Howells1-0/+1
Since the keyring facility can be viewed as a cache (at least in some applications), the local expiration time on the key should probably be viewed as a 'needs updating after this time' property rather than an absolute 'anyone now wanting to use this object is out of luck' property. Since request_key() is the main interface for the usage of keys, this should update or replace an expired key rather than issuing EKEYEXPIRED if the local expiration has been reached (ie. it should refresh the cache). For absolute conditions where refreshing the cache probably doesn't help, the key can be negatively instantiated using KEYCTL_REJECT_KEY with EKEYEXPIRED given as the error to issue. This will still cause request_key() to return EKEYEXPIRED as that was explicitly set. In the future, if the key type has an update op available, we might want to upcall with the expired key and allow the upcall to update it. We would pass a different operation name (the first column in /etc/request-key.conf) to the request-key program. request_key() returning EKEYEXPIRED is causing an NFS problem which Chuck Lever describes thusly: After about 10 minutes, my NFSv4 functional tests fail because the ownership of the test files goes to "-2". Looking at /proc/keys shows that the id_resolv keys that map to my test user ID have expired. The ownership problem persists until the expired keys are purged from the keyring, and fresh keys are obtained. I bisected the problem to 3.13 commit b2a4df200d57 ("KEYS: Expand the capacity of a keyring"). This commit inadvertantly changes the API contract of the internal function keyring_search_aux(). The root cause appears to be that b2a4df200d57 made "no state check" the default behavior. "No state check" means the keyring search iterator function skips checking the key's expiry timeout, and returns expired keys. request_key_and_link() depends on getting an -EAGAIN result code to know when to perform an upcall to refresh an expired key. This patch can be tested directly by: keyctl request2 user debug:fred a @s keyctl timeout %user:debug:fred 3 sleep 4 keyctl request2 user debug:fred a @s Without the patch, the last command gives error EKEYEXPIRED, but with the command it gives a new key. Reported-by: Carl Hetherington <cth@carlh.net> Reported-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: David Howells <dhowells@redhat.com> Tested-by: Chuck Lever <chuck.lever@oracle.com>
2014-09-16KEYS: Make the key matching functions return boolDavid Howells1-4/+4
Make the key matching functions pointed to by key_match_data::cmp return bool rather than int. Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Vivek Goyal <vgoyal@redhat.com>
2014-09-16KEYS: Remove key_type::match in favour of overriding default by match_preparseDavid Howells1-0/+2
A previous patch added a ->match_preparse() method to the key type. This is allowed to override the function called by the iteration algorithm. Therefore, we can just set a default that simply checks for an exact match of the key description with the original criterion data and allow match_preparse to override it as needed. The key_type::match op is then redundant and can be removed, as can the user_match() function. Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Vivek Goyal <vgoyal@redhat.com>
2014-09-16KEYS: Remove key_type::def_lookup_typeDavid Howells1-6/+5
Remove key_type::def_lookup_type as it's no longer used. The information now defaults to KEYRING_SEARCH_LOOKUP_DIRECT but may be overridden by type->match_preparse(). Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Vivek Goyal <vgoyal@redhat.com>
2014-09-16KEYS: Preparse match dataDavid Howells1-5/+3
Preparse the match data. This provides several advantages: (1) The preparser can reject invalid criteria up front. (2) The preparser can convert the criteria to binary data if necessary (the asymmetric key type really wants to do binary comparison of the key IDs). (3) The preparser can set the type of search to be performed. This means that it's not then a one-off setting in the key type. (4) The preparser can set an appropriate comparator function. Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Vivek Goyal <vgoyal@redhat.com>
2014-03-14KEYS: Move the flags representing required permission to linux/key.hDavid Howells1-10/+1
Move the flags representing required permission to linux/key.h as the perm parameter of security_key_permission() is in terms of them - and not the permissions mask flags used in key->perm. Whilst we're at it: (1) Rename them to be KEY_NEED_xxx rather than KEY_xxx to avoid collisions with symbols in uapi/linux/input.h. (2) Don't use key_perm_t for a mask of required permissions, but rather limit it to the permissions mask attached to the key and arguments related directly to that. Signed-off-by: David Howells <dhowells@redhat.com> Tested-by: Dmitry Kasatkin <d.kasatkin@samsung.com>
2013-09-24KEYS: Add per-user_namespace registers for persistent per-UID kerberos cachesDavid Howells1-0/+9
Add support for per-user_namespace registers of persistent per-UID kerberos caches held within the kernel. This allows the kerberos cache to be retained beyond the life of all a user's processes so that the user's cron jobs can work. The kerberos cache is envisioned as a keyring/key tree looking something like: struct user_namespace \___ .krb_cache keyring - The register \___ _krb.0 keyring - Root's Kerberos cache \___ _krb.5000 keyring - User 5000's Kerberos cache \___ _krb.5001 keyring - User 5001's Kerberos cache \___ tkt785 big_key - A ccache blob \___ tkt12345 big_key - Another ccache blob Or possibly: struct user_namespace \___ .krb_cache keyring - The register \___ _krb.0 keyring - Root's Kerberos cache \___ _krb.5000 keyring - User 5000's Kerberos cache \___ _krb.5001 keyring - User 5001's Kerberos cache \___ tkt785 keyring - A ccache \___ krbtgt/REDHAT.COM@REDHAT.COM big_key \___ http/REDHAT.COM@REDHAT.COM user \___ afs/REDHAT.COM@REDHAT.COM user \___ nfs/REDHAT.COM@REDHAT.COM user \___ krbtgt/KERNEL.ORG@KERNEL.ORG big_key \___ http/KERNEL.ORG@KERNEL.ORG big_key What goes into a particular Kerberos cache is entirely up to userspace. Kernel support is limited to giving you the Kerberos cache keyring that you want. The user asks for their Kerberos cache by: krb_cache = keyctl_get_krbcache(uid, dest_keyring); The uid is -1 or the user's own UID for the user's own cache or the uid of some other user's cache (requires CAP_SETUID). This permits rpc.gssd or whatever to mess with the cache. The cache returned is a keyring named "_krb.<uid>" that the possessor can read, search, clear, invalidate, unlink from and add links to. Active LSMs get a chance to rule on whether the caller is permitted to make a link. Each uid's cache keyring is created when it first accessed and is given a timeout that is extended each time this function is called so that the keyring goes away after a while. The timeout is configurable by sysctl but defaults to three days. Each user_namespace struct gets a lazily-created keyring that serves as the register. The cache keyrings are added to it. This means that standard key search and garbage collection facilities are available. The user_namespace struct's register goes away when it does and anything left in it is then automatically gc'd. Signed-off-by: David Howells <dhowells@redhat.com> Tested-by: Simo Sorce <simo@redhat.com> cc: Serge E. Hallyn <serge.hallyn@ubuntu.com> cc: Eric W. Biederman <ebiederm@xmission.com>
2013-09-24KEYS: Expand the capacity of a keyringDavid Howells1-6/+11
Expand the capacity of a keyring to be able to hold a lot more keys by using the previously added associative array implementation. Currently the maximum capacity is: (PAGE_SIZE - sizeof(header)) / sizeof(struct key *) which, on a 64-bit system, is a little more 500. However, since this is being used for the NFS uid mapper, we need more than that. The new implementation gives us effectively unlimited capacity. With some alterations, the keyutils testsuite runs successfully to completion after this patch is applied. The alterations are because (a) keyrings that are simply added to no longer appear ordered and (b) some of the errors have changed a bit. Signed-off-by: David Howells <dhowells@redhat.com>
2013-09-24KEYS: Drop the permissions argument from __keyring_search_one()David Howells1-2/+1
Drop the permissions argument from __keyring_search_one() as the only caller passes 0 here - which causes all checks to be skipped. Signed-off-by: David Howells <dhowells@redhat.com>
2013-09-24KEYS: Introduce a search context structureDavid Howells1-16/+24
Search functions pass around a bunch of arguments, each of which gets copied with each call. Introduce a search context structure to hold these. Whilst we're at it, create a search flag that indicates whether the search should be directly to the description or whether it should iterate through all keys looking for a non-description match. This will be useful when keyrings use a generic data struct with generic routines to manage their content as the search terms can just be passed through to the iterator callback function. Also, for future use, the data to be supplied to the match function is separated from the description pointer in the search context. This makes it clear which is being supplied. Signed-off-by: David Howells <dhowells@redhat.com>
2013-09-24KEYS: Consolidate the concept of an 'index key' for key accessDavid Howells1-5/+3
Consolidate the concept of an 'index key' for accessing keys. The index key is the search term needed to find a key directly - basically the key type and the key description. We can add to that the description length. This will be useful when turning a keyring into an associative array rather than just a pointer block. Signed-off-by: David Howells <dhowells@redhat.com>
2013-09-24KEYS: key_is_dead() should take a const key pointer argumentDavid Howells1-1/+1
key_is_dead() should take a const key pointer argument as it doesn't modify what it points to. Signed-off-by: David Howells <dhowells@redhat.com>
2013-09-24KEYS: Skip key state checks when checking for possessionDavid Howells1-0/+1
Skip key state checks (invalidation, revocation and expiration) when checking for possession. Without this, keys that have been marked invalid, revoked keys and expired keys are not given a possession attribute - which means the possessor is not granted any possession permits and cannot do anything with them unless they also have one a user, group or other permit. This causes failures in the keyutils test suite's revocation and expiration tests now that commit 96b5c8fea6c0861621051290d705ec2e971963f1 reduced the initial permissions granted to a key. The failures are due to accesses to revoked and expired keys being given EACCES instead of EKEYREVOKED or EKEYEXPIRED. Signed-off-by: David Howells <dhowells@redhat.com>
2013-05-08aio: don't include aio.h in sched.hKent Overstreet1-0/+2
Faster kernel compiles by way of fewer unnecessary includes. [akpm@linux-foundation.org: fix fallout] [akpm@linux-foundation.org: fix build] Signed-off-by: Kent Overstreet <koverstreet@google.com> Cc: Zach Brown <zab@redhat.com> Cc: Felipe Balbi <balbi@ti.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Mark Fasheh <mfasheh@suse.com> Cc: Joel Becker <jlbec@evilplan.org> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Jens Axboe <axboe@kernel.dk> Cc: Asai Thambi S P <asamymuthupa@micron.com> Cc: Selvan Mani <smani@micron.com> Cc: Sam Bradshaw <sbradshaw@micron.com> Cc: Jeff Moyer <jmoyer@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Benjamin LaHaise <bcrl@kvack.org> Reviewed-by: "Theodore Ts'o" <tytso@mit.edu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-09-14userns: Convert security/keys to the new userns infrastructureEric W. Biederman1-4/+2
- 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>
2012-07-24Merge branch 'next' of ↵Linus Torvalds1-1/+1
git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security Pull security subsystem updates from James Morris: "Nothing groundbreaking for this kernel, just cleanups and fixes, and a couple of Smack enhancements." * 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security: (21 commits) Smack: Maintainer Record Smack: don't show empty rules when /smack/load or /smack/load2 is read Smack: user access check bounds Smack: onlycap limits on CAP_MAC_ADMIN Smack: fix smack_new_inode bogosities ima: audit is compiled only when enabled ima: ima_initialized is set only if successful ima: add policy for pseudo fs ima: remove unused cleanup functions ima: free securityfs violations file ima: use full pathnames in measurement list security: Fix nommu build. samples: seccomp: add .gitignore for untracked executables tpm: check the chip reference before using it TPM: fix memleak when register hardware fails TPM: chip disabled state erronously being reported as error MAINTAINERS: TPM maintainers' contacts update Merge branches 'next-queue' and 'next' into next Remove unused code from MPI library Revert "crypto: GnuPG based MPI lib - additional sources (part 4)" ...
2012-07-22merge task_work and rcu_head, get rid of separate allocation for keyring caseAl Viro1-5/+1
task_work and rcu_head are identical now; merge them (calling the result struct callback_head, rcu_head #define'd to it), kill separate allocation in security/keys since we can just use cred->rcu now. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-07-22trimming task_work: kill ->dataAl Viro1-0/+4
get rid of the only user of ->data; this is _not_ the final variant - in the end we'll have task_work and rcu_head identical and just use cred->rcu, at which point the separate allocation will be gone completely. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-06-10Merge commit 'v3.5-rc2' into nextJames Morris1-0/+2
2012-05-25KEYS: Fix some sparse warningsDavid Howells1-1/+1
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>
2012-05-24keys: change keyctl_session_to_parent() to use task_work_add()Oleg Nesterov1-0/+2
Change keyctl_session_to_parent() to use task_work_add() and move key_replace_session_keyring() logic into task_work->func(). Note that we do task_work_cancel() before task_work_add() to ensure that only one work can be pending at any time. This is important, we must not allow user-space to abuse the parent's ->task_works list. The callback, replace_session_keyring(), checks PF_EXITING. I guess this is not really needed but looks better. As a side effect, this fixes the (unlikely) race. The callers of key_replace_session_keyring() and keyctl_session_to_parent() lack the necessary barriers, the parent can miss the request. Now we can remove task_struct->replacement_session_keyring and related code. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: David Howells <dhowells@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Richard Kuo <rkuo@codeaurora.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Alexander Gordeev <agordeev@redhat.com> Cc: Chris Zankel <chris@zankel.net> Cc: David Smith <dsmith@redhat.com> Cc: "Frank Ch. Eigler" <fche@redhat.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Larry Woodman <lwoodman@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Tejun Heo <tj@kernel.org> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-05-11KEYS: Add invalidation supportDavid Howells1-1/+14
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>
2012-01-18keys: add a "logon" key typeJeff Layton1-0/+1
For CIFS, we want to be able to store NTLM credentials (aka username and password) in the keyring. We do not, however want to allow users to fetch those keys back out of the keyring since that would be a security risk. Unfortunately, due to the nuances of key permission bits, it's not possible to do this. We need to grant search permissions so the kernel can find these keys, but that also implies permissions to read the payload. Resolve this by adding a new key_type. This key type is essentially the same as key_type_user, but does not define a .read op. This prevents the payload from ever being visible from userspace. This key type also vets the description to ensure that it's "qualified" by checking to ensure that it has a ':' in it that is preceded by other characters. Acked-by: David Howells <dhowells@redhat.com> Signed-off-by: Jeff Layton <jlayton@redhat.com> Signed-off-by: Steve French <smfrench@gmail.com>
2011-08-23KEYS: Correctly destroy key payloads when their keytype is removedDavid Howells1-1/+3
unregister_key_type() has code to mark a key as dead and make it unavailable in one loop and then destroy all those unavailable key payloads in the next loop. However, the loop to mark keys dead renders the key undetectable to the second loop by changing the key type pointer also. Fix this by the following means: (1) The key code has two garbage collectors: one deletes unreferenced keys and the other alters keyrings to delete links to old dead, revoked and expired keys. They can end up holding each other up as both want to scan the key serial tree under spinlock. Combine these into a single routine. (2) Move the dead key marking, dead link removal and dead key removal into the garbage collector as a three phase process running over the three cycles of the normal garbage collection procedure. This is tracked by the KEY_GC_REAPING_DEAD_1, _2 and _3 state flags. unregister_key_type() then just unlinks the key type from the list, wakes up the garbage collector and waits for the third phase to complete. (3) Downgrade the key types sem in unregister_key_type() once it has deleted the key type from the list so that it doesn't block the keyctl() syscall. (4) Dead keys that cannot be simply removed in the third phase have their payloads destroyed with the key's semaphore write-locked to prevent interference by the keyctl() syscall. There should be no in-kernel users of dead keys of that type by the point of unregistration, though keyctl() may be holding a reference. (5) Only perform timer recalculation in the GC if the timer actually expired. If it didn't, we'll get another cycle when it goes off - and if the key that actually triggered it has been removed, it's not a problem. (6) Only garbage collect link if the timer expired or if we're doing dead key clean up phase 2. (7) As only key_garbage_collector() is permitted to use rb_erase() on the key serial tree, it doesn't need to revalidate its cursor after dropping the spinlock as the node the cursor points to must still exist in the tree. (8) Drop the spinlock in the GC if there is contention on it or if we need to reschedule. After dealing with that, get the spinlock again and resume scanning. This has been tested in the following ways: (1) Run the keyutils testsuite against it. (2) Using the AF_RXRPC and RxKAD modules to test keytype removal: Load the rxrpc_s key type: # insmod /tmp/af-rxrpc.ko # insmod /tmp/rxkad.ko Create a key (http://people.redhat.com/~dhowells/rxrpc/listen.c): # /tmp/listen & [1] 8173 Find the key: # grep rxrpc_s /proc/keys 091086e1 I--Q-- 1 perm 39390000 0 0 rxrpc_s 52:2 Link it to a session keyring, preferably one with a higher serial number: # keyctl link 0x20e36251 @s Kill the process (the key should remain as it's linked to another place): # fg /tmp/listen ^C Remove the key type: rmmod rxkad rmmod af-rxrpc This can be made a more effective test by altering the following part of the patch: if (unlikely(gc_state & KEY_GC_REAPING_DEAD_2)) { /* Make sure everyone revalidates their keys if we marked a * bunch as being dead and make sure all keyring ex-payloads * are destroyed. */ kdebug("dead sync"); synchronize_rcu(); To call synchronize_rcu() in GC phase 1 instead. That causes that the keyring's old payload content to hang around longer until it's RCU destroyed - which usually happens after GC phase 3 is complete. This allows the destroy_dead_key branch to be tested. Reported-by: Benjamin Coddington <bcodding@gmail.com> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: James Morris <jmorris@namei.org>
2011-08-23KEYS: Move the unreferenced key reaper to the keys garbage collector fileDavid Howells1-0/+2
Move the unreferenced key reaper function to the keys garbage collector file as that's a more appropriate place with the dead key link reaper. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: James Morris <jmorris@namei.org>
2011-03-17KEYS: Improve /proc/keysDavid Howells1-1/+3
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>
2011-03-08KEYS: Add an iovec version of KEYCTL_INSTANTIATEDavid Howells1-0/+7
Add a keyctl op (KEYCTL_INSTANTIATE_IOV) that is like KEYCTL_INSTANTIATE, but takes an iovec array and concatenates the data in-kernel into one buffer. Since the KEYCTL_INSTANTIATE copies the data anyway, this isn't too much of a problem. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: James Morris <jmorris@namei.org>
2011-03-08KEYS: Add a new keyctl op to reject a key with a specified error codeDavid Howells1-0/+1
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>
2011-01-26KEYS: Fix __key_link_end() quota fixup on errorDavid Howells1-3/+3
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>
2011-01-22KEYS: Fix up comments in key management codeDavid Howells1-12/+14
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>
2010-08-12Add a dummy printk function for the maintenance of unused printksDavid Howells1-5/+0
Add a dummy printk function for the maintenance of unused printks through gcc format checking, and also so that side-effect checking is maintained too. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-02KEYS: Make /proc/keys check to see if a key is possessed before security checkDavid Howells1-0/+5
Make /proc/keys check to see if the calling process possesses each key before performing the security check. The possession check can be skipped if the key doesn't have the possessor-view permission bit set. This causes the keys a process possesses to show up in /proc/keys, even if they don't have matching user/group/other view permissions. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: James Morris <jmorris@namei.org>
2010-05-27umh: creds: convert call_usermodehelper_keys() to use subprocess_info->init()Oleg Nesterov1-0/+1
call_usermodehelper_keys() uses call_usermodehelper_setkeys() to change subprocess_info->cred in advance. Now that we have info->init() we can change this code to set tgcred->session_keyring in context of execing kernel thread. Note: since currently call_usermodehelper_keys() is never called with UMH_NO_WAIT, call_usermodehelper_keys()->key_get() and umh_keys_cleanup() are not really needed, we could rely on install_session_keyring_to_cred() which does key_get() on success. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Neil Horman <nhorman@tuxdriver.com> Acked-by: David Howells <dhowells@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-06KEYS: Do preallocation for __key_link()David Howells1-1/+10
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>
2009-09-02KEYS: Add a keyctl to install a process's session keyring on its parent [try #6]David Howells1-0/+1
Add a keyctl to install a process's session keyring onto its parent. This replaces the parent's session keyring. Because the COW credential code does not permit one process to change another process's credentials directly, the change is deferred until userspace next starts executing again. Normally this will be after a wait*() syscall. To support this, three new security hooks have been provided: cred_alloc_blank() to allocate unset security creds, cred_transfer() to fill in the blank security creds and key_session_to_parent() - which asks the LSM if the process may replace its parent's session keyring. The replacement may only happen if the process has the same ownership details as its parent, and the process has LINK permission on the session keyring, and the session keyring is owned by the process, and the LSM permits it. Note that this requires alteration to each architecture's notify_resume path. This has been done for all arches barring blackfin, m68k* and xtensa, all of which need assembly alteration to support TIF_NOTIFY_RESUME. This allows the replacement to be performed at the point the parent process resumes userspace execution. This allows the userspace AFS pioctl emulation to fully emulate newpag() and the VIOCSETTOK and VIOCSETTOK2 pioctls, all of which require the ability to alter the parent process's PAG membership. However, since kAFS doesn't use PAGs per se, but rather dumps the keys into the session keyring, the session keyring of the parent must be replaced if, for example, VIOCSETTOK is passed the newpag flag. This can be tested with the following program: #include <stdio.h> #include <stdlib.h> #include <keyutils.h> #define KEYCTL_SESSION_TO_PARENT 18 #define OSERROR(X, S) do { if ((long)(X) == -1) { perror(S); exit(1); } } while(0) int main(int argc, char **argv) { key_serial_t keyring, key; long ret; keyring = keyctl_join_session_keyring(argv[1]); OSERROR(keyring, "keyctl_join_session_keyring"); key = add_key("user", "a", "b", 1, keyring); OSERROR(key, "add_key"); ret = keyctl(KEYCTL_SESSION_TO_PARENT); OSERROR(ret, "KEYCTL_SESSION_TO_PARENT"); return 0; } Compiled and linked with -lkeyutils, you should see something like: [dhowells@andromeda ~]$ keyctl show Session Keyring -3 --alswrv 4043 4043 keyring: _ses 355907932 --alswrv 4043 -1 \_ keyring: _uid.4043 [dhowells@andromeda ~]$ /tmp/newpag [dhowells@andromeda ~]$ keyctl show Session Keyring -3 --alswrv 4043 4043 keyring: _ses 1055658746 --alswrv 4043 4043 \_ user: a [dhowells@andromeda ~]$ /tmp/newpag hello [dhowells@andromeda ~]$ keyctl show Session Keyring -3 --alswrv 4043 4043 keyring: hello 340417692 --alswrv 4043 4043 \_ user: a Where the test program creates a new session keyring, sticks a user key named 'a' into it and then installs it on its parent. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: James Morris <jmorris@namei.org>
2009-09-02KEYS: Add garbage collection for dead, revoked and expired keys. [try #6]David Howells1-0/+4
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>
2009-09-02KEYS: Deal with dead-type keys appropriately [try #6]David Howells1-1/+4
Allow keys for which the key type has been removed to be unlinked. Currently dead-type keys can only be disposed of by completely clearing the keyrings that point to them. Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Serge Hallyn <serue@us.ibm.com> Signed-off-by: James Morris <jmorris@namei.org>
2009-02-27keys: distinguish per-uid keys in different namespacesSerge E. Hallyn1-1/+3
per-uid keys were looked by uid only. Use the user namespace to distinguish the same uid in different namespaces. This does not address key_permission. So a task can for instance try to join a keyring owned by the same uid in another namespace. That will be handled by a separate patch. 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>
2008-11-14CRED: Inaugurate COW credentialsDavid Howells1-8/+9
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>
2008-11-14KEYS: Alter use of key instantiation link-to-keyring argumentDavid Howells1-5/+7
Alter the use of the key instantiation and negation functions' link-to-keyring arguments. Currently this specifies a keyring in the target process to link the key into, creating the keyring if it doesn't exist. This, however, can be a problem for copy-on-write credentials as it means that the instantiating process can alter the credentials of the requesting process. This patch alters the behaviour such that: (1) If keyctl_instantiate_key() or keyctl_negate_key() are given a specific keyring by ID (ringid >= 0), then that keyring will be used. (2) If keyctl_instantiate_key() or keyctl_negate_key() are given one of the special constants that refer to the requesting process's keyrings (KEY_SPEC_*_KEYRING, all <= 0), then: (a) If sys_request_key() was given a keyring to use (destringid) then the key will be attached to that keyring. (b) If sys_request_key() was given a NULL keyring, then the key being instantiated will be attached to the default keyring as set by keyctl_set_reqkey_keyring(). (3) No extra link will be made. Decision point (1) follows current behaviour, and allows those instantiators who've searched for a specifically named keyring in the requestor's keyring so as to partition the keys by type to still have their named keyrings. Decision point (2) allows the requestor to make sure that the key or keys that get produced by request_key() go where they want, whilst allowing the instantiator to request that the key is retained. This is mainly useful for situations where the instantiator makes a secondary request, the key for which should be retained by the initial requestor: +-----------+ +--------------+ +--------------+ | | | | | | | Requestor |------->| Instantiator |------->| Instantiator | | | | | | | +-----------+ +--------------+ +--------------+ request_key() request_key() This might be useful, for example, in Kerberos, where the requestor requests a ticket, and then the ticket instantiator requests the TGT, which someone else then has to go and fetch. The TGT, however, should be retained in the keyrings of the requestor, not the first instantiator. To make this explict an extra special keyring constant is also added. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: James Morris <jmorris@namei.org> Signed-off-by: James Morris <jmorris@namei.org>
2008-11-14KEYS: Disperse linux/key_ui.hDavid Howells1-1/+30
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>
2008-06-06keys: remove unused key_alloc_semDaniel Walker1-1/+0
This semaphore doesn't appear to be used, so remove it. Signed-off-by: Daniel Walker <dwalker@mvista.com> Cc: David Howells <dhowells@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-29keys: make the keyring quotas controllable through /proc/sysDavid Howells1-4/+10
Make the keyring quotas controllable through /proc/sys files: (*) /proc/sys/kernel/keys/root_maxkeys /proc/sys/kernel/keys/root_maxbytes Maximum number of keys that root may have and the maximum total number of bytes of data that root may have stored in those keys. (*) /proc/sys/kernel/keys/maxkeys /proc/sys/kernel/keys/maxbytes Maximum number of keys that each non-root user may have and the maximum total number of bytes of data that each of those users may have stored in their keys. Also increase the quotas as a number of people have been complaining that it's not big enough. I'm not sure that it's big enough now either, but on the other hand, it can now be set in /etc/sysctl.conf. Signed-off-by: David Howells <dhowells@redhat.com> Cc: <kwc@citi.umich.edu> Cc: <arunsr@cse.iitk.ac.in> Cc: <dwalsh@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-29keys: don't generate user and user session keyrings unless they're accessedDavid Howells1-3/+1
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>
2008-04-29keys: add keyctl function to get a security labelDavid Howells1-1/+2
Add a keyctl() function to get the security label of a key. The following is added to Documentation/keys.txt: (*) Get the LSM security context attached to a key. long keyctl(KEYCTL_GET_SECURITY, key_serial_t key, char *buffer, size_t buflen) This function returns a string that represents the LSM security context attached to a key in the buffer provided. Unless there's an error, it always returns the amount of data it could produce, even if that's too big for the buffer, but it won't copy more than requested to userspace. If the buffer pointer is NULL then no copy will take place. A NUL character is included at the end of the string if the buffer is sufficiently big. This is included in the returned count. If no LSM is in force then an empty string will be returned. A process must have view permission on the key for this function to be successful. [akpm@linux-foundation.org: declare keyctl_get_security()] Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Stephen Smalley <sds@tycho.nsa.gov> Cc: Paul Moore <paul.moore@hp.com> Cc: Chris Wright <chrisw@sous-sol.org> Cc: James Morris <jmorris@namei.org> Cc: Kevin Coffman <kwc@citi.umich.edu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-29keys: allow the callout data to be passed as a blob rather than a stringDavid Howells1-3/+6
Allow the callout data to be passed as a blob rather than a string for internal kernel services that call any request_key_*() interface other than request_key(). request_key() itself still takes a NUL-terminated string. The functions that change are: request_key_with_auxdata() request_key_async() request_key_async_with_auxdata() 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> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-18security: replace remaining __FUNCTION__ occurrencesHarvey Harrison1-4/+4
__FUNCTION__ is gcc-specific, use __func__ Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com> Cc: James Morris <jmorris@namei.org> Cc: Stephen Smalley <sds@tycho.nsa.gov> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: James Morris <jmorris@namei.org>
2007-10-17KEYS: Make request_key() and co fundamentally asynchronousDavid Howells1-12/+23
Make request_key() and co fundamentally asynchronous to make it easier for NFS to make use of them. There are now accessor functions that do asynchronous constructions, a wait function to wait for construction to complete, and a completion function for the key type to indicate completion of construction. Note that the construction queue is now gone. Instead, keys under construction are linked in to the appropriate keyring in advance, and that anyone encountering one must wait for it to be complete before they can use it. This is done automatically for userspace. The following auxiliary changes are also made: (1) Key type implementation stuff is split from linux/key.h into linux/key-type.h. (2) AF_RXRPC provides a way to allocate null rxrpc-type keys so that AFS does not need to call key_instantiate_and_link() directly. (3) Adjust the debugging macros so that they're -Wformat checked even if they are disabled, and make it so they can be enabled simply by defining __KDEBUG to be consistent with other code of mine. (3) Documentation. [alan@lxorguk.ukuu.org.uk: keys: missing word in documentation] Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2006-06-29[PATCH] Keys: Allow in-kernel key requestor to pass auxiliary data to upcallerDavid Howells1-0/+1
The proposed NFS key type uses its own method of passing key requests to userspace (upcalling) rather than invoking /sbin/request-key. This is because the responsible userspace daemon should already be running and will be contacted through rpc_pipefs. This patch permits the NFS filesystem to pass auxiliary data to the upcall operation (struct key_type::request_key) so that the upcaller can use a pre-existing communications channel more easily. Signed-off-by: David Howells <dhowells@redhat.com> Acked-By: Kevin Coffman <kwc@citi.umich.edu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>