Pull security subsystem updates from James Morris:
"A quiet cycle for the security subsystem with just a few maintenance
updates."
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security:
Smack: create a sysfs mount point for smackfs
Smack: use select not depends in Kconfig
Yama: remove locking from delete path
Yama: add RCU to drop read locking
drivers/char/tpm: remove tasklet and cleanup
KEYS: Use keyring_alloc() to create special keyrings
KEYS: Reduce initial permissions on keys
KEYS: Make the session and process keyrings per-thread
seccomp: Make syscall skipping and nr changes more consistent
key: Fix resource leak
keys: Fix unreachable code
KEYS: Add payload preparsing opportunity prior to key instantiate or update
Reduce the initial permissions on new keys to grant the possessor everything,
view permission only to the user (so the keys can be seen in /proc/keys) and
nothing else.
This gives the creator a chance to adjust the permissions mask before other
processes can access the new key or create a link to it.
To aid with this, keyring_alloc() now takes a permission argument rather than
setting the permissions itself.
The following permissions are now set:
(1) The user and user-session keyrings grant the user that owns them full
permissions and grant a possessor everything bar SETATTR.
(2) The process and thread keyrings grant the possessor full permissions but
only grant the user VIEW. This permits the user to see them in
/proc/keys, but not to do anything with them.
(3) Anonymous session keyrings grant the possessor full permissions, but only
grant the user VIEW and READ. This means that the user can see them in
/proc/keys and can list them, but nothing else. Possibly READ shouldn't
be provided either.
(4) Named session keyrings grant everything an anonymous session keyring does,
plus they grant the user LINK permission. The whole point of named
session keyrings is that others can also subscribe to them. Possibly this
should be a separate permission to LINK.
(5) The temporary session keyring created by call_sbin_request_key() gets the
same permissions as an anonymous session keyring.
(6) Keys created by add_key() get VIEW, SEARCH, LINK and SETATTR for the
possessor, plus READ and/or WRITE if the key type supports them. The used
only gets VIEW now.
(7) Keys created by request_key() now get the same as those created by
add_key().
Reported-by: Lennart Poettering <lennart@poettering.net>
Reported-by: Stef Walter <stefw@redhat.com>
Signed-off-by: David Howells <dhowells@redhat.com>
- 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>
This commit removes the extraneous parentheses from rcu_assign_keypointer()
so that rcu_assign_pointer() can be wrapped in do-while. It also wraps
rcu_assign_keypointer() in a do-while and parenthesizes its final argument,
as suggested by David Howells.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
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>
Don't bother checking for NULL key pointer in key_validate() as all of the
places that call it will crash anyway if the relevant key pointer is NULL by
the time they call key_validate(). Therefore, the checking must be done prior
to calling here.
Whilst we're at it, simplify the key_validate() function a bit and mark its
argument const.
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>
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>
Do an LRU discard in keyrings that are full rather than returning ENFILE. To
perform this, a time_t is added to the key struct and updated by the creation
of a link to a key and by a key being found as the result of a search. At the
completion of a successful search, the keyrings in the path between the root of
the search and the first found link to it also have their last-used times
updated.
Note that discarding a link to a key from a keyring does not necessarily
destroy the key as there may be references held by other places.
An alternate discard method that might suffice is to perform FIFO discard from
the keyring, using the spare 2-byte hole in the keylist header as the index of
the next link to be discarded.
This is useful when using a keyring as a cache for DNS results or foreign
filesystem IDs.
This can be tested by the following. As root do:
echo 1000 >/proc/sys/kernel/keys/root_maxkeys
kr=`keyctl newring foo @s`
for ((i=0; i<2000; i++)); do keyctl add user a$i a $kr; done
Without this patch ENFILE should be reported when the keyring fills up. With
this patch, the keyring discards keys in an LRU fashion. Note that the stored
LRU time has a granularity of 1s.
After doing this, /proc/key-users can be observed and should show that most of
the 2000 keys have been discarded:
[root@andromeda ~]# cat /proc/key-users
0: 517 516/516 513/1000 5249/20000
The "513/1000" here is the number of quota-accounted keys present for this user
out of the maximum permitted.
In /proc/keys, the keyring shows the number of keys it has and the number of
slots it has allocated:
[root@andromeda ~]# grep foo /proc/keys
200c64c4 I--Q-- 1 perm 3b3f0000 0 0 keyring foo: 509/509
The maximum is (PAGE_SIZE - header) / key pointer size. That's typically 509
on a 64-bit system and 1020 on a 32-bit system.
Signed-off-by: David Howells <dhowells@redhat.com>
Make the keys garbage collector invoke synchronize_rcu() prior to destroying
keys with a zero usage count. This means that a key can be examined under the
RCU read lock in the safe knowledge that it won't get deallocated until after
the lock is released - even if its usage count becomes zero whilst we're
looking at it.
This is useful in keyring search vs key link. Consider a keyring containing a
link to a key. That link can be replaced in-place in the keyring without
requiring an RCU copy-and-replace on the keyring contents without breaking a
search underway on that keyring when the displaced key is released, provided
the key is actually destroyed only after the RCU read lock held by the search
algorithm is released.
This permits __key_link() to replace a key without having to reallocate the key
payload. A key gets replaced if a new key being linked into a keyring has the
same type and description.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Jeff Layton <jlayton@redhat.com>
Pull NFS client updates for Linux 3.4 from Trond Myklebust:
"New features include:
- Add NFS client support for containers.
This should enable most of the necessary functionality, including
lockd support, and support for rpc.statd, NFSv4 idmapper and
RPCSEC_GSS upcalls into the correct network namespace from which
the mount system call was issued.
- NFSv4 idmapper scalability improvements
Base the idmapper cache on the keyring interface to allow
concurrent access to idmapper entries. Start the process of
migrating users from the single-threaded daemon-based approach to
the multi-threaded request-key based approach.
- NFSv4.1 implementation id.
Allows the NFSv4.1 client and server to mutually identify each
other for logging and debugging purposes.
- Support the 'vers=4.1' mount option for mounting NFSv4.1 instead of
having to use the more counterintuitive 'vers=4,minorversion=1'.
- SUNRPC tracepoints.
Start the process of adding tracepoints in order to improve
debugging of the RPC layer.
- pNFS object layout support for autologin.
Important bugfixes include:
- Fix a bug in rpc_wake_up/rpc_wake_up_status that caused them to
fail to wake up all tasks when applied to priority waitqueues.
- Ensure that we handle read delegations correctly, when we try to
truncate a file.
- A number of fixes for NFSv4 state manager loops (mostly to do with
delegation recovery)."
* tag 'nfs-for-3.4-1' of git://git.linux-nfs.org/projects/trondmy/linux-nfs: (224 commits)
NFS: fix sb->s_id in nfs debug prints
xprtrdma: Remove assumption that each segment is <= PAGE_SIZE
xprtrdma: The transport should not bug-check when a dup reply is received
pnfs-obj: autologin: Add support for protocol autologin
NFS: Remove nfs4_setup_sequence from generic rename code
NFS: Remove nfs4_setup_sequence from generic unlink code
NFS: Remove nfs4_setup_sequence from generic read code
NFS: Remove nfs4_setup_sequence from generic write code
NFS: Fix more NFS debug related build warnings
SUNRPC/LOCKD: Fix build warnings when CONFIG_SUNRPC_DEBUG is undefined
nfs: non void functions must return a value
SUNRPC: Kill compiler warning when RPC_DEBUG is unset
SUNRPC/NFS: Add Kbuild dependencies for NFS_DEBUG/RPC_DEBUG
NFS: Use cond_resched_lock() to reduce latencies in the commit scans
NFSv4: It is not safe to dereference lsp->ls_state in release_lockowner
NFS: ncommit count is being double decremented
SUNRPC: We must not use list_for_each_entry_safe() in rpc_wake_up()
Try using machine credentials for RENEW calls
NFSv4.1: Fix a few issues in filelayout_commit_pagelist
NFSv4.1: Clean ups and bugfixes for the pNFS read/writeback/commit code
...
The keyctl_set_timeout function isn't exported to other parts of the
kernel, but I want to use it for the NFS idmapper. I already have the
key, but I wanted a generic way to set the timeout.
Signed-off-by: Bryan Schumaker <bjschuma@netapp.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Permit key_serial() to be called with a const key pointer.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
The kernel contains some special internal keyrings, for instance the DNS
resolver keyring :
2a93faf1 I----- 1 perm 1f030000 0 0 keyring .dns_resolver: empty
It would occasionally be useful to allow the contents of such keyrings to be
flushed by root (cache invalidation).
Allow a flag to be set on a keyring to mark that someone possessing the
sysadmin capability can clear the keyring, even without normal write access to
the keyring.
Set this flag on the special keyrings created by the DNS resolver, the NFS
identity mapper and the CIFS identity mapper.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Jeff Layton <jlayton@redhat.com>
Acked-by: Steve Dickson <steved@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
Define rcu_assign_keypointer(), which uses the key payload.rcudata instead
of payload.data, to resolve the CONFIG_SPARSE_RCU_POINTER message:
"incompatible types in comparison expression (different address spaces)"
Replace the rcu_assign_pointer() calls in encrypted/trusted keys with
rcu_assign_keypointer().
Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
* 'docs-move' of git://git.kernel.org/pub/scm/linux/kernel/git/rdunlap/linux-docs:
Create Documentation/security/, move LSM-, credentials-, and keys-related files from Documentation/ to Documentation/security/, add Documentation/security/00-INDEX, and update all occurrences of Documentation/<moved_file> to Documentation/security/<moved_file>.
move LSM-, credentials-, and keys-related files from Documentation/
to Documentation/security/,
add Documentation/security/00-INDEX, and
update all occurrences of Documentation/<moved_file>
to Documentation/security/<moved_file>.
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>
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>
Add an RCU payload dereference macro as this seems to be a common piece of code
amongst key types that use RCU referenced payloads.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
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>
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>
