It was possible for an unprivileged user to create the user and user
session keyrings for another user.  For example:

    sudo -u '#3000' sh -c 'keyctl add keyring _uid.4000 "" @u
                           keyctl add keyring _uid_ses.4000 "" @u
                           sleep 15' &
    sleep 1
    sudo -u '#4000' keyctl describe @u
    sudo -u '#4000' keyctl describe @us

This is problematic because these "fake" keyrings won't have the right
permissions.  In particular, the user who created them first will own
them and will have full access to them via the possessor permissions,
which can be used to compromise the security of a user's keys:

    -4: alswrv-----v------------  3000     0 keyring: _uid.4000
    -5: alswrv-----v------------  3000     0 keyring: _uid_ses.4000

Fix it by marking user and user session keyrings with a flag
KEY_FLAG_UID_KEYRING.  Then, when searching for a user or user session
keyring by name, skip all keyrings that don't have the flag set.

Fixes: 69664cf1 ("keys: don't generate user and user session keyrings unless they're accessed")
Cc: <stable@vger.kernel.org>	[v2.6.26+]
Signed-off-by: NEric Biggers <ebiggers@google.com>
Signed-off-by: NDavid Howells <dhowells@redhat.com>

If a key's refcount is dropped to zero between key_lookup() peeking at
the refcount and subsequently attempting to increment it, refcount_inc()
will see a zero refcount.  Here, refcount_inc() will WARN_ONCE(), and
will *not* increment the refcount, which will remain zero.

Once key_lookup() drops key_serial_lock, it is possible for the key to
be freed behind our back.

This patch uses refcount_inc_not_zero() to perform the peek and increment
atomically.

Fixes: fff29291 ("security, keys: convert key.usage from atomic_t to refcount_t")
Signed-off-by: NMark Rutland <mark.rutland@arm.com>
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Cc: David Windsor <dwindsor@gmail.com>
Cc: Elena Reshetova <elena.reshetova@intel.com>
Cc: Hans Liljestrand <ishkamiel@gmail.com>
Cc: James Morris <james.l.morris@oracle.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: NJames Morris <james.l.morris@oracle.com>

key_update() freed the key_preparsed_payload even if it was not
initialized first.  This would cause a crash if userspace called
keyctl_update() on a key with type like "asymmetric" that has a
->preparse() method but not an ->update() method.  Possibly it could
even be triggered for other key types by racing with keyctl_setperm() to
make the KEY_NEED_WRITE check fail (the permission was already checked,
so normally it wouldn't fail there).

Reproducer with key type "asymmetric", given a valid cert.der:

keyctl new_session
keyid=$(keyctl padd asymmetric desc @s < cert.der)
keyctl setperm $keyid 0x3f000000
keyctl update $keyid data

[  150.686666] BUG: unable to handle kernel NULL pointer dereference at 0000000000000001
[  150.687601] IP: asymmetric_key_free_kids+0x12/0x30
[  150.688139] PGD 38a3d067
[  150.688141] PUD 3b3de067
[  150.688447] PMD 0
[  150.688745]
[  150.689160] Oops: 0000 [#1] SMP
[  150.689455] Modules linked in:
[  150.689769] CPU: 1 PID: 2478 Comm: keyctl Not tainted 4.11.0-rc4-xfstests-00187-ga9f6b6b8 #742
[  150.690916] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-20170228_101828-anatol 04/01/2014
[  150.692199] task: ffff88003b30c480 task.stack: ffffc90000350000
[  150.692952] RIP: 0010:asymmetric_key_free_kids+0x12/0x30
[  150.693556] RSP: 0018:ffffc90000353e58 EFLAGS: 00010202
[  150.694142] RAX: 0000000000000000 RBX: 0000000000000001 RCX: 0000000000000004
[  150.694845] RDX: ffffffff81ee3920 RSI: ffff88003d4b0700 RDI: 0000000000000001
[  150.697569] RBP: ffffc90000353e60 R08: ffff88003d5d2140 R09: 0000000000000000
[  150.702483] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001
[  150.707393] R13: 0000000000000004 R14: ffff880038a4d2d8 R15: 000000000040411f
[  150.709720] FS:  00007fcbcee35700(0000) GS:ffff88003fd00000(0000) knlGS:0000000000000000
[  150.711504] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  150.712733] CR2: 0000000000000001 CR3: 0000000039eab000 CR4: 00000000003406e0
[  150.714487] Call Trace:
[  150.714975]  asymmetric_key_free_preparse+0x2f/0x40
[  150.715907]  key_update+0xf7/0x140
[  150.716560]  ? key_default_cmp+0x20/0x20
[  150.717319]  keyctl_update_key+0xb0/0xe0
[  150.718066]  SyS_keyctl+0x109/0x130
[  150.718663]  entry_SYSCALL_64_fastpath+0x1f/0xc2
[  150.719440] RIP: 0033:0x7fcbce75ff19
[  150.719926] RSP: 002b:00007ffd5d167088 EFLAGS: 00000206 ORIG_RAX: 00000000000000fa
[  150.720918] RAX: ffffffffffffffda RBX: 0000000000404d80 RCX: 00007fcbce75ff19
[  150.721874] RDX: 00007ffd5d16785e RSI: 000000002866cd36 RDI: 0000000000000002
[  150.722827] RBP: 0000000000000006 R08: 000000002866cd36 R09: 00007ffd5d16785e
[  150.723781] R10: 0000000000000004 R11: 0000000000000206 R12: 0000000000404d80
[  150.724650] R13: 00007ffd5d16784d R14: 00007ffd5d167238 R15: 000000000040411f
[  150.725447] Code: 83 c4 08 31 c0 5b 41 5c 41 5d 41 5e 41 5f 5d c3 66 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 85 ff 74 23 55 48 89 e5 53 48 89 fb <48> 8b 3f e8 06 21 c5 ff 48 8b 7b 08 e8 fd 20 c5 ff 48 89 df e8
[  150.727489] RIP: asymmetric_key_free_kids+0x12/0x30 RSP: ffffc90000353e58
[  150.728117] CR2: 0000000000000001
[  150.728430] ---[ end trace f7f8fe1da2d5ae8d ]---

Fixes: 4d8c0250 ("KEYS: Call ->free_preparse() even after ->preparse() returns an error")
Cc: stable@vger.kernel.org # 3.17+
Signed-off-by: NEric Biggers <ebiggers@google.com>
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NJames Morris <james.l.morris@oracle.com>

The keyring restrict callback was sometimes called before
__key_link_begin and sometimes after, which meant that the keyring
semaphores were not always held during the restrict callback.

If the semaphores are consistently acquired before checking link
restrictions, keyring contents cannot be changed after the restrict
check is complete but before the evaluated key is linked to the keyring.
Signed-off-by: NMat Martineau <mathew.j.martineau@linux.intel.com>

Replace struct key's restrict_link function pointer with a pointer to
the new struct key_restriction. The structure contains pointers to the
restriction function as well as relevant data for evaluating the
restriction.

The garbage collector checks restrict_link->keytype when key types are
unregistered. Restrictions involving a removed key type are converted
to use restrict_link_reject so that restrictions cannot be removed by
unregistering key types.
Signed-off-by: NMat Martineau <mathew.j.martineau@linux.intel.com>

The first argument to the restrict_link_func_t functions was a keyring
pointer. These functions are called by the key subsystem with this
argument set to the destination keyring, but restrict_link_by_signature
expects a pointer to the relevant trusted keyring.

Restrict functions may need something other than a single struct key
pointer to allow or reject key linkage, so the data used to make that
decision (such as the trust keyring) is moved to a new, fourth
argument. The first argument is now always the destination keyring.
Signed-off-by: NMat Martineau <mathew.j.martineau@linux.intel.com>

This pointer type needs to be returned from a lookup function, and
without a typedef the syntax gets cumbersome.
Signed-off-by: NMat Martineau <mathew.j.martineau@linux.intel.com>

refcount_t type and corresponding API should be
used instead of atomic_t when the variable is used as
a reference counter. This allows to avoid accidental
refcounter overflows that might lead to use-after-free
situations.
Signed-off-by: NElena Reshetova <elena.reshetova@intel.com>
Signed-off-by: NHans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: NKees Cook <keescook@chromium.org>
Signed-off-by: NDavid Windsor <dwindsor@gmail.com>
Acked-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NJames Morris <james.l.morris@oracle.com>

refcount_t type and corresponding API should be
used instead of atomic_t when the variable is used as
a reference counter. This allows to avoid accidental
refcounter overflows that might lead to use-after-free
situations.
Signed-off-by: NElena Reshetova <elena.reshetova@intel.com>
Signed-off-by: NHans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: NKees Cook <keescook@chromium.org>
Signed-off-by: NDavid Windsor <dwindsor@gmail.com>
Acked-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NJames Morris <james.l.morris@oracle.com>

If __key_link_begin() failed then "edit" would be uninitialized.  I've
added a check to fix that.

This allows a random user to crash the kernel, though it's quite
difficult to achieve.  There are three ways it can be done as the user
would have to cause an error to occur in __key_link():

 (1) Cause the kernel to run out of memory.  In practice, this is difficult
     to achieve without ENOMEM cropping up elsewhere and aborting the
     attempt.

 (2) Revoke the destination keyring between the keyring ID being looked up
     and it being tested for revocation.  In practice, this is difficult to
     time correctly because the KEYCTL_REJECT function can only be used
     from the request-key upcall process.  Further, users can only make use
     of what's in /sbin/request-key.conf, though this does including a
     rejection debugging test - which means that the destination keyring
     has to be the caller's session keyring in practice.

 (3) Have just enough key quota available to create a key, a new session
     keyring for the upcall and a link in the session keyring, but not then
     sufficient quota to create a link in the nominated destination keyring
     so that it fails with EDQUOT.

The bug can be triggered using option (3) above using something like the
following:

	echo 80 >/proc/sys/kernel/keys/root_maxbytes
	keyctl request2 user debug:fred negate @t

The above sets the quota to something much lower (80) to make the bug
easier to trigger, but this is dependent on the system.  Note also that
the name of the keyring created contains a random number that may be
between 1 and 10 characters in size, so may throw the test off by
changing the amount of quota used.

Assuming the failure occurs, something like the following will be seen:

	kfree_debugcheck: out of range ptr 6b6b6b6b6b6b6b68h
	------------[ cut here ]------------
	kernel BUG at ../mm/slab.c:2821!
	...
	RIP: 0010:[<ffffffff811600f9>] kfree_debugcheck+0x20/0x25
	RSP: 0018:ffff8804014a7de8  EFLAGS: 00010092
	RAX: 0000000000000034 RBX: 6b6b6b6b6b6b6b68 RCX: 0000000000000000
	RDX: 0000000000040001 RSI: 00000000000000f6 RDI: 0000000000000300
	RBP: ffff8804014a7df0 R08: 0000000000000001 R09: 0000000000000000
	R10: ffff8804014a7e68 R11: 0000000000000054 R12: 0000000000000202
	R13: ffffffff81318a66 R14: 0000000000000000 R15: 0000000000000001
	...
	Call Trace:
	  kfree+0xde/0x1bc
	  assoc_array_cancel_edit+0x1f/0x36
	  __key_link_end+0x55/0x63
	  key_reject_and_link+0x124/0x155
	  keyctl_reject_key+0xb6/0xe0
	  keyctl_negate_key+0x10/0x12
	  SyS_keyctl+0x9f/0xe7
	  do_syscall_64+0x63/0x13a
	  entry_SYSCALL64_slow_path+0x25/0x25

Fixes: f70e2e06 ('KEYS: Do preallocation for __key_link()')
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NDavid Howells <dhowells@redhat.com>
cc: stable@vger.kernel.org
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Remove KEY_FLAG_TRUSTED and KEY_ALLOC_TRUSTED as they're no longer
meaningful.  Also we can drop the trusted flag from the preparse structure.

Given this, we no longer need to pass the key flags through to
restrict_link().

Further, we can now get rid of keyring_restrict_trusted_only() also.
Signed-off-by: NDavid Howells <dhowells@redhat.com>

Add a facility whereby proposed new links to be added to a keyring can be
vetted, permitting them to be rejected if necessary.  This can be used to
block public keys from which the signature cannot be verified or for which
the signature verification fails.  It could also be used to provide
blacklisting.

This affects operations like add_key(), KEYCTL_LINK and KEYCTL_INSTANTIATE.

To this end:

 (1) A function pointer is added to the key struct that, if set, points to
     the vetting function.  This is called as:

	int (*restrict_link)(struct key *keyring,
			     const struct key_type *key_type,
			     unsigned long key_flags,
			     const union key_payload *key_payload),

     where 'keyring' will be the keyring being added to, key_type and
     key_payload will describe the key being added and key_flags[*] can be
     AND'ed with KEY_FLAG_TRUSTED.

     [*] This parameter will be removed in a later patch when
     	 KEY_FLAG_TRUSTED is removed.

     The function should return 0 to allow the link to take place or an
     error (typically -ENOKEY, -ENOPKG or -EKEYREJECTED) to reject the
     link.

     The pointer should not be set directly, but rather should be set
     through keyring_alloc().

     Note that if called during add_key(), preparse is called before this
     method, but a key isn't actually allocated until after this function
     is called.

 (2) KEY_ALLOC_BYPASS_RESTRICTION is added.  This can be passed to
     key_create_or_update() or key_instantiate_and_link() to bypass the
     restriction check.

 (3) KEY_FLAG_TRUSTED_ONLY is removed.  The entire contents of a keyring
     with this restriction emplaced can be considered 'trustworthy' by
     virtue of being in the keyring when that keyring is consulted.

 (4) key_alloc() and keyring_alloc() take an extra argument that will be
     used to set restrict_link in the new key.  This ensures that the
     pointer is set before the key is published, thus preventing a window
     of unrestrictedness.  Normally this argument will be NULL.

 (5) As a temporary affair, keyring_restrict_trusted_only() is added.  It
     should be passed to keyring_alloc() as the extra argument instead of
     setting KEY_FLAG_TRUSTED_ONLY on a keyring.  This will be replaced in
     a later patch with functions that look in the appropriate places for
     authoritative keys.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Reviewed-by: NMimi Zohar <zohar@linux.vnet.ibm.com>

Add KEY_ALLOC_BUILT_IN to convey that a key should have KEY_FLAG_BUILTIN
set rather than setting it after the fact.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Acked-by: NMimi Zohar <zohar@linux.vnet.ibm.com>

KEY_FLAG_KEEP should only be applied to a key if the keyring it is being
linked into has KEY_FLAG_KEEP set.

To this end, partially revert the following patch:

	commit 1d6d167c
	Author: Mimi Zohar <zohar@linux.vnet.ibm.com>
	Date:   Thu Jan 7 07:46:36 2016 -0500
	KEYS: refcount bug fix

to undo the change that made it unconditional (Mimi got it right the first
time).

Without undoing this change, it becomes impossible to delete, revoke or
invalidate keys added to keyrings through __key_instantiate_and_link()
where the keyring has itself been linked to.  To test this, run the
following command sequence:

    keyctl newring foo @s
    keyctl add user a a %:foo
    keyctl unlink %user:a %:foo
    keyctl clear %:foo

With the commit mentioned above the third and fourth commands fail with
EPERM when they should succeed.
Reported-by: NStephen Gallager <sgallagh@redhat.com>
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Acked-by: NMimi Zohar <zohar@linux.vnet.ibm.com>
cc: Mimi Zohar <zohar@linux.vnet.ibm.com>
cc: keyrings@vger.kernel.org
cc: stable@vger.kernel.org
Signed-off-by: NJames Morris <james.l.morris@oracle.com>

This patch fixes the key_ref leak, removes the unnecessary KEY_FLAG_KEEP
test before setting the flag, and cleans up the if/then brackets style
introduced in commit:
d3600bcf KEYS: prevent keys from being removed from specified keyrings
Reported-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NMimi Zohar <zohar@linux.vnet.ibm.com>
Acked-by: NDavid Howells <dhowells@redhat.com>

Userspace should not be allowed to remove keys from certain keyrings
(eg. blacklist), though the keys themselves can expire.

This patch defines a new key flag named KEY_FLAG_KEEP to prevent
userspace from being able to unlink, revoke, invalidate or timed
out a key on a keyring.  When this flag is set on the keyring, all
keys subsequently added are flagged.

In addition, when this flag is set, the keyring itself can not be
cleared.
Signed-off-by: NMimi Zohar <zohar@linux.vnet.ibm.com>
Cc: David Howells <dhowells@redhat.com>

Merge the type-specific data with the payload data into one four-word chunk
as it seems pointless to keep them separate.

Use user_key_payload() for accessing the payloads of overloaded
user-defined keys.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
cc: linux-cifs@vger.kernel.org
cc: ecryptfs@vger.kernel.org
cc: linux-ext4@vger.kernel.org
cc: linux-f2fs-devel@lists.sourceforge.net
cc: linux-nfs@vger.kernel.org
cc: ceph-devel@vger.kernel.org
cc: linux-ima-devel@lists.sourceforge.net

key->description and key->index_key.description are same because
they are unioned. But, for readability, using same name for
duplication and validation seems better.
Signed-off-by: NInsu Yun <wuninsu@gmail.com>
Signed-off-by: NDavid Howells <dhowells@redhat.com>

We already checked if "desc" was NULL at the beginning of the function
and we've dereferenced it so this causes a static checker warning.
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NJames Morris <james.l.morris@oracle.com>

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: NDavid Howells <dhowells@redhat.com>
Acked-by: NVivek Goyal <vgoyal@redhat.com>

Now that NFS client uses the kernel key ring facility to store the NFSv4
id/gid mappings, the defaults for root_maxkeys and root_maxbytes need to be
substantially increased.

These values have been soak tested:

	https://bugzilla.redhat.com/show_bug.cgi?id=1033708#c73Signed-off-by: NSteve Dickson <steved@redhat.com>
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NJames Morris <james.l.morris@oracle.com>

Call the ->free_preparse() key type op even after ->preparse() returns an
error as it does cleaning up type stuff.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Acked-by: NSteve Dickson <steved@redhat.com>
Acked-by: NJeff Layton <jlayton@primarydata.com>
Reviewed-by: NSage Weil <sage@redhat.com>

Allow a key type's preparsing routine to set the expiry time for a key.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Acked-by: NSteve Dickson <steved@redhat.com>
Acked-by: NJeff Layton <jlayton@primarydata.com>
Reviewed-by: NSage Weil <sage@redhat.com>

struct key_preparsed_payload should have two payload pointers to correspond
with those in struct key.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Acked-by: NSteve Dickson <steved@redhat.com>
Acked-by: NJeff Layton <jlayton@primarydata.com>
Reviewed-by: NSage Weil <sage@redhat.com>

Provide a generic instantiation function for key types that use the preparse
hook.  This makes it easier to prereserve key quota before keyrings get locked
to retain the new key.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Acked-by: NSteve Dickson <steved@redhat.com>
Acked-by: NJeff Layton <jlayton@primarydata.com>
Reviewed-by: NSage Weil <sage@redhat.com>

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: NDavid Howells <dhowells@redhat.com>
Tested-by: NDmitry Kasatkin <d.kasatkin@samsung.com>

The second word of key->payload does not get initialised in key_alloc(), but
the big_key type is relying on it having been cleared.  The problem comes when
big_key fails to instantiate a large key and doesn't then set the payload.  The
big_key_destroy() op is called from the garbage collector and this assumes that
the dentry pointer stored in the second word will be NULL if instantiation did
not complete.

Therefore just pre-clear the entire struct key on allocation rather than trying
to be clever and only initialising to 0 only those bits that aren't otherwise
initialised.

The lack of initialisation can lead to a bug report like the following if
big_key failed to initialise its file:

	general protection fault: 0000 [#1] SMP
	Modules linked in: ...
	CPU: 0 PID: 51 Comm: kworker/0:1 Not tainted 3.10.0-53.el7.x86_64 #1
	Hardware name: Dell Inc. PowerEdge 1955/0HC513, BIOS 1.4.4 12/09/2008
	Workqueue: events key_garbage_collector
	task: ffff8801294f5680 ti: ffff8801296e2000 task.ti: ffff8801296e2000
	RIP: 0010:[<ffffffff811b4a51>] dput+0x21/0x2d0
	...
	Call Trace:
	 [<ffffffff811a7b06>] path_put+0x16/0x30
	 [<ffffffff81235604>] big_key_destroy+0x44/0x60
	 [<ffffffff8122dc4b>] key_gc_unused_keys.constprop.2+0x5b/0xe0
	 [<ffffffff8122df2f>] key_garbage_collector+0x1df/0x3c0
	 [<ffffffff8107759b>] process_one_work+0x17b/0x460
	 [<ffffffff8107834b>] worker_thread+0x11b/0x400
	 [<ffffffff81078230>] ? rescuer_thread+0x3e0/0x3e0
	 [<ffffffff8107eb00>] kthread+0xc0/0xd0
	 [<ffffffff8107ea40>] ? kthread_create_on_node+0x110/0x110
	 [<ffffffff815c4bec>] ret_from_fork+0x7c/0xb0
	 [<ffffffff8107ea40>] ? kthread_create_on_node+0x110/0x110
Reported-by: NPatrik Kis <pkis@redhat.com>
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Reviewed-by: NStephen Gallagher <sgallagh@redhat.com>

key_reject_and_link() marking a key as negative and setting the error with
which it was negated races with keyring searches and other things that read
that error.

The fix is to switch the order in which the assignments are done in
key_reject_and_link() and to use memory barriers.

Kudos to Dave Wysochanski <dwysocha@redhat.com> and Scott Mayhew
<smayhew@redhat.com> for tracking this down.

This may be the cause of:

BUG: unable to handle kernel NULL pointer dereference at 0000000000000070
IP: [<ffffffff81219011>] wait_for_key_construction+0x31/0x80
PGD c6b2c3067 PUD c59879067 PMD 0
Oops: 0000 [#1] SMP
last sysfs file: /sys/devices/system/cpu/cpu3/cache/index2/shared_cpu_map
CPU 0
Modules linked in: ...

Pid: 13359, comm: amqzxma0 Not tainted 2.6.32-358.20.1.el6.x86_64 #1 IBM System x3650 M3 -[7945PSJ]-/00J6159
RIP: 0010:[<ffffffff81219011>] wait_for_key_construction+0x31/0x80
RSP: 0018:ffff880c6ab33758  EFLAGS: 00010246
RAX: ffffffff81219080 RBX: 0000000000000000 RCX: 0000000000000002
RDX: ffffffff81219060 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffff880c6ab33768 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: ffff880adfcbce40
R13: ffffffffa03afb84 R14: ffff880adfcbce40 R15: ffff880adfcbce43
FS:  00007f29b8042700(0000) GS:ffff880028200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000070 CR3: 0000000c613dc000 CR4: 00000000000007f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Process amqzxma0 (pid: 13359, threadinfo ffff880c6ab32000, task ffff880c610deae0)
Stack:
 ffff880adfcbce40 0000000000000000 ffff880c6ab337b8 ffffffff81219695
<d> 0000000000000000 ffff880a000000d0 ffff880c6ab337a8 000000000000000f
<d> ffffffffa03afb93 000000000000000f ffff88186c7882c0 0000000000000014
Call Trace:
 [<ffffffff81219695>] request_key+0x65/0xa0
 [<ffffffffa03a0885>] nfs_idmap_request_key+0xc5/0x170 [nfs]
 [<ffffffffa03a0eb4>] nfs_idmap_lookup_id+0x34/0x80 [nfs]
 [<ffffffffa03a1255>] nfs_map_group_to_gid+0x75/0xa0 [nfs]
 [<ffffffffa039a9ad>] decode_getfattr_attrs+0xbdd/0xfb0 [nfs]
 [<ffffffff81057310>] ? __dequeue_entity+0x30/0x50
 [<ffffffff8100988e>] ? __switch_to+0x26e/0x320
 [<ffffffffa039ae03>] decode_getfattr+0x83/0xe0 [nfs]
 [<ffffffffa039b610>] ? nfs4_xdr_dec_getattr+0x0/0xa0 [nfs]
 [<ffffffffa039b69f>] nfs4_xdr_dec_getattr+0x8f/0xa0 [nfs]
 [<ffffffffa02dada4>] rpcauth_unwrap_resp+0x84/0xb0 [sunrpc]
 [<ffffffffa039b610>] ? nfs4_xdr_dec_getattr+0x0/0xa0 [nfs]
 [<ffffffffa02cf923>] call_decode+0x1b3/0x800 [sunrpc]
 [<ffffffff81096de0>] ? wake_bit_function+0x0/0x50
 [<ffffffffa02cf770>] ? call_decode+0x0/0x800 [sunrpc]
 [<ffffffffa02d99a7>] __rpc_execute+0x77/0x350 [sunrpc]
 [<ffffffff81096c67>] ? bit_waitqueue+0x17/0xd0
 [<ffffffffa02d9ce1>] rpc_execute+0x61/0xa0 [sunrpc]
 [<ffffffffa02d03a5>] rpc_run_task+0x75/0x90 [sunrpc]
 [<ffffffffa02d04c2>] rpc_call_sync+0x42/0x70 [sunrpc]
 [<ffffffffa038ff80>] _nfs4_call_sync+0x30/0x40 [nfs]
 [<ffffffffa038836c>] _nfs4_proc_getattr+0xac/0xc0 [nfs]
 [<ffffffff810aac87>] ? futex_wait+0x227/0x380
 [<ffffffffa038b856>] nfs4_proc_getattr+0x56/0x80 [nfs]
 [<ffffffffa0371403>] __nfs_revalidate_inode+0xe3/0x220 [nfs]
 [<ffffffffa037158e>] nfs_revalidate_mapping+0x4e/0x170 [nfs]
 [<ffffffffa036f147>] nfs_file_read+0x77/0x130 [nfs]
 [<ffffffff811811aa>] do_sync_read+0xfa/0x140
 [<ffffffff81096da0>] ? autoremove_wake_function+0x0/0x40
 [<ffffffff8100bb8e>] ? apic_timer_interrupt+0xe/0x20
 [<ffffffff8100b9ce>] ? common_interrupt+0xe/0x13
 [<ffffffff81228ffb>] ? selinux_file_permission+0xfb/0x150
 [<ffffffff8121bed6>] ? security_file_permission+0x16/0x20
 [<ffffffff81181a95>] vfs_read+0xb5/0x1a0
 [<ffffffff81181bd1>] sys_read+0x51/0x90
 [<ffffffff810dc685>] ? __audit_syscall_exit+0x265/0x290
 [<ffffffff8100b072>] system_call_fastpath+0x16/0x1b
Signed-off-by: NDavid Howells <dhowells@redhat.com>
cc: Dave Wysochanski <dwysocha@redhat.com>
cc: Scott Mayhew <smayhew@redhat.com>

Add KEY_FLAG_TRUSTED to indicate that a key either comes from a trusted source
or had a cryptographic signature chain that led back to a trusted key the
kernel already possessed.

Add KEY_FLAGS_TRUSTED_ONLY to indicate that a keyring will only accept links to
keys marked with KEY_FLAGS_TRUSTED.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Reviewed-by: NKees Cook <keescook@chromium.org>

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: NDavid Howells <dhowells@redhat.com>

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: NDavid Howells <dhowells@redhat.com>

Define a __key_get() wrapper to use rather than atomic_inc() on the key usage
count as this makes it easier to hook in refcount error debugging.
Signed-off-by: NDavid Howells <dhowells@redhat.com>

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: NDavid Howells <dhowells@redhat.com>

Give the key type the opportunity to preparse the payload prior to the
instantiation and update routines being called.  This is done with the
provision of two new key type operations:

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

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

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

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

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

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

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

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

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

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

and the new payload data is passed in *prep, whether or not it was preparsed.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

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: NLennart Poettering <lennart@poettering.net>
Reported-by: NStef Walter <stefw@redhat.com>
Signed-off-by: NDavid 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: NEric W. Biederman <ebiederm@xmission.com>

Give the key type the opportunity to preparse the payload prior to the
instantiation and update routines being called.  This is done with the
provision of two new key type operations:

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

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

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

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

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

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

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

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

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

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

and the new payload data is passed in *prep, whether or not it was preparsed.
Signed-off-by: NDavid Howells <dhowells@redhat.com>

system_nrt[_freezable]_wq are now spurious.  Mark them deprecated and
convert all users to system[_freezable]_wq.

If you're cc'd and wondering what's going on: Now all workqueues are
non-reentrant, so there's no reason to use system_nrt[_freezable]_wq.
Please use system[_freezable]_wq instead.

This patch doesn't make any functional difference.
Signed-off-by: NTejun Heo <tj@kernel.org>
Acked-By: NLai Jiangshan <laijs@cn.fujitsu.com>

Cc: Jens Axboe <axboe@kernel.dk>
Cc: David Airlie <airlied@linux.ie>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: David Howells <dhowells@redhat.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: NDavid Howells <dhowells@redhat.com>

Announce the (un)registration of a key type in the core key code rather than
in the callers.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Acked-by: NMimi Zohar <zohar@us.ibm.com>