-----BEGIN PGP SIGNATURE-----
iQIzBAABCAAdFiEEqG5UsNXhtOCrfGQP+7dXa6fLC2sFAl7U/i8ACgkQ+7dXa6fL
C2u2eg/+Oy6ybq0hPovYVkFI9WIG7ZCz7w9Q6BEnfYMqqn3dnfJxKQ3l4pnQEOWw
f4QfvpvevsYfMtOJkYcG6s66rQgbFdqc5TEyBBy0QNp3acRolN7IXkcopvv9xOpQ
JxedpbFG1PTFLWjvBpyjlrUPouwLzq2FXAf1Ox0ZIMw6165mYOMWoli1VL8dh0A0
Ai7JUB0WrvTNbrwhV413obIzXT/rPCdcrgbQcgrrLPex8lQ47ZAE9bq6k4q5HiwK
KRzEqkQgnzId6cCNTFBfkTWsx89zZunz7jkfM5yx30MvdAtPSxvvpfIPdZRZkXsP
E2K9Fk1/6OQZTC0Op3Pi/bt+hVG/mD1p0sQUDgo2MO3qlSS+5mMkR8h3mJEgwK12
72P4YfOJkuAy2z3v4lL0GYdUDAZY6i6G8TMxERKu/a9O3VjTWICDOyBUS6F8YEAK
C7HlbZxAEOKTVK0BTDTeEUBwSeDrBbvH6MnRlZCG5g1Fos2aWP0udhjiX8IfZLO7
GN6nWBvK1fYzfsUczdhgnoCzQs3suoDo04HnsTPGJ8De52T4x2RsjV+gPx0nrNAq
eWChl1JvMWsY2B3GLnl9XQz4NNN+EreKEkk+PULDGllrArrPsp5Vnhb9FJO1PVCU
hMDJHohPiXnKbc8f4Bd78OhIvnuoGfJPdM5MtNe2flUKy2a2ops=
=YTGf
-----END PGP SIGNATURE-----
Merge tag 'notifications-20200601' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs
Pull notification queue from David Howells:
"This adds a general notification queue concept and adds an event
source for keys/keyrings, such as linking and unlinking keys and
changing their attributes.
Thanks to Debarshi Ray, we do have a pull request to use this to fix a
problem with gnome-online-accounts - as mentioned last time:
https://gitlab.gnome.org/GNOME/gnome-online-accounts/merge_requests/47
Without this, g-o-a has to constantly poll a keyring-based kerberos
cache to find out if kinit has changed anything.
[ There are other notification pending: mount/sb fsinfo notifications
for libmount that Karel Zak and Ian Kent have been working on, and
Christian Brauner would like to use them in lxc, but let's see how
this one works first ]
LSM hooks are included:
- A set of hooks are provided that allow an LSM to rule on whether or
not a watch may be set. Each of these hooks takes a different
"watched object" parameter, so they're not really shareable. The
LSM should use current's credentials. [Wanted by SELinux & Smack]
- A hook is provided to allow an LSM to rule on whether or not a
particular message may be posted to a particular queue. This is
given the credentials from the event generator (which may be the
system) and the watch setter. [Wanted by Smack]
I've provided SELinux and Smack with implementations of some of these
hooks.
WHY
===
Key/keyring notifications are desirable because if you have your
kerberos tickets in a file/directory, your Gnome desktop will monitor
that using something like fanotify and tell you if your credentials
cache changes.
However, we also have the ability to cache your kerberos tickets in
the session, user or persistent keyring so that it isn't left around
on disk across a reboot or logout. Keyrings, however, cannot currently
be monitored asynchronously, so the desktop has to poll for it - not
so good on a laptop. This facility will allow the desktop to avoid the
need to poll.
DESIGN DECISIONS
================
- The notification queue is built on top of a standard pipe. Messages
are effectively spliced in. The pipe is opened with a special flag:
pipe2(fds, O_NOTIFICATION_PIPE);
The special flag has the same value as O_EXCL (which doesn't seem
like it will ever be applicable in this context)[?]. It is given up
front to make it a lot easier to prohibit splice&co from accessing
the pipe.
[?] Should this be done some other way? I'd rather not use up a new
O_* flag if I can avoid it - should I add a pipe3() system call
instead?
The pipe is then configured::
ioctl(fds[1], IOC_WATCH_QUEUE_SET_SIZE, queue_depth);
ioctl(fds[1], IOC_WATCH_QUEUE_SET_FILTER, &filter);
Messages are then read out of the pipe using read().
- It should be possible to allow write() to insert data into the
notification pipes too, but this is currently disabled as the
kernel has to be able to insert messages into the pipe *without*
holding pipe->mutex and the code to make this work needs careful
auditing.
- sendfile(), splice() and vmsplice() are disabled on notification
pipes because of the pipe->mutex issue and also because they
sometimes want to revert what they just did - but one or more
notification messages might've been interleaved in the ring.
- The kernel inserts messages with the wait queue spinlock held. This
means that pipe_read() and pipe_write() have to take the spinlock
to update the queue pointers.
- Records in the buffer are binary, typed and have a length so that
they can be of varying size.
This allows multiple heterogeneous sources to share a common
buffer; there are 16 million types available, of which I've used
just a few, so there is scope for others to be used. Tags may be
specified when a watchpoint is created to help distinguish the
sources.
- Records are filterable as types have up to 256 subtypes that can be
individually filtered. Other filtration is also available.
- Notification pipes don't interfere with each other; each may be
bound to a different set of watches. Any particular notification
will be copied to all the queues that are currently watching for it
- and only those that are watching for it.
- When recording a notification, the kernel will not sleep, but will
rather mark a queue as having lost a message if there's
insufficient space. read() will fabricate a loss notification
message at an appropriate point later.
- The notification pipe is created and then watchpoints are attached
to it, using one of:
keyctl_watch_key(KEY_SPEC_SESSION_KEYRING, fds[1], 0x01);
watch_mount(AT_FDCWD, "/", 0, fd, 0x02);
watch_sb(AT_FDCWD, "/mnt", 0, fd, 0x03);
where in both cases, fd indicates the queue and the number after is
a tag between 0 and 255.
- Watches are removed if either the notification pipe is destroyed or
the watched object is destroyed. In the latter case, a message will
be generated indicating the enforced watch removal.
Things I want to avoid:
- Introducing features that make the core VFS dependent on the
network stack or networking namespaces (ie. usage of netlink).
- Dumping all this stuff into dmesg and having a daemon that sits
there parsing the output and distributing it as this then puts the
responsibility for security into userspace and makes handling
namespaces tricky. Further, dmesg might not exist or might be
inaccessible inside a container.
- Letting users see events they shouldn't be able to see.
TESTING AND MANPAGES
====================
- The keyutils tree has a pipe-watch branch that has keyctl commands
for making use of notifications. Proposed manual pages can also be
found on this branch, though a couple of them really need to go to
the main manpages repository instead.
If the kernel supports the watching of keys, then running "make
test" on that branch will cause the testing infrastructure to spawn
a monitoring process on the side that monitors a notifications pipe
for all the key/keyring changes induced by the tests and they'll
all be checked off to make sure they happened.
https://git.kernel.org/pub/scm/linux/kernel/git/dhowells/keyutils.git/log/?h=pipe-watch
- A test program is provided (samples/watch_queue/watch_test) that
can be used to monitor for keyrings, mount and superblock events.
Information on the notifications is simply logged to stdout"
* tag 'notifications-20200601' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs:
smack: Implement the watch_key and post_notification hooks
selinux: Implement the watch_key security hook
keys: Make the KEY_NEED_* perms an enum rather than a mask
pipe: Add notification lossage handling
pipe: Allow buffers to be marked read-whole-or-error for notifications
Add sample notification program
watch_queue: Add a key/keyring notification facility
security: Add hooks to rule on setting a watch
pipe: Add general notification queue support
pipe: Add O_NOTIFICATION_PIPE
security: Add a hook for the point of notification insertion
uapi: General notification queue definitions
For kvmalloc'ed data object that contains sensitive information like
cryptographic keys, we need to make sure that the buffer is always cleared
before freeing it. Using memset() alone for buffer clearing may not
provide certainty as the compiler may compile it away. To be sure, the
special memzero_explicit() has to be used.
This patch introduces a new kvfree_sensitive() for freeing those sensitive
data objects allocated by kvmalloc(). The relevant places where
kvfree_sensitive() can be used are modified to use it.
Fixes: 4f0882491a ("KEYS: Avoid false positive ENOMEM error on key read")
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Acked-by: David Howells <dhowells@redhat.com>
Cc: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Cc: James Morris <jmorris@namei.org>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Cc: Joe Perches <joe@perches.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Uladzislau Rezki <urezki@gmail.com>
Link: http://lkml.kernel.org/r/20200407200318.11711-1-longman@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Since the meaning of combining the KEY_NEED_* constants is undefined, make
it so that you can't do that by turning them into an enum.
The enum is also given some extra values to represent special
circumstances, such as:
(1) The '0' value is reserved and causes a warning to trap the parameter
being unset.
(2) The key is to be unlinked and we require no permissions on it, only
the keyring, (this replaces the KEY_LOOKUP_FOR_UNLINK flag).
(3) An override due to CAP_SYS_ADMIN.
(4) An override due to an instantiation token being present.
(5) The permissions check is being deferred to later key_permission()
calls.
The extra values give the opportunity for LSMs to audit these situations.
[Note: This really needs overhauling so that lookup_user_key() tells
key_task_permission() and the LSM what operation is being done and leaves
it to those functions to decide how to map that onto the available
permits. However, I don't really want to make these change in the middle
of the notifications patchset.]
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
cc: Paul Moore <paul@paul-moore.com>
cc: Stephen Smalley <stephen.smalley.work@gmail.com>
cc: Casey Schaufler <casey@schaufler-ca.com>
cc: keyrings@vger.kernel.org
cc: selinux@vger.kernel.org
Add a key/keyring change notification facility whereby notifications about
changes in key and keyring content and attributes can be received.
Firstly, an event queue needs to be created:
pipe2(fds, O_NOTIFICATION_PIPE);
ioctl(fds[1], IOC_WATCH_QUEUE_SET_SIZE, 256);
then a notification can be set up to report notifications via that queue:
struct watch_notification_filter filter = {
.nr_filters = 1,
.filters = {
[0] = {
.type = WATCH_TYPE_KEY_NOTIFY,
.subtype_filter[0] = UINT_MAX,
},
},
};
ioctl(fds[1], IOC_WATCH_QUEUE_SET_FILTER, &filter);
keyctl_watch_key(KEY_SPEC_SESSION_KEYRING, fds[1], 0x01);
After that, records will be placed into the queue when events occur in
which keys are changed in some way. Records are of the following format:
struct key_notification {
struct watch_notification watch;
__u32 key_id;
__u32 aux;
} *n;
Where:
n->watch.type will be WATCH_TYPE_KEY_NOTIFY.
n->watch.subtype will indicate the type of event, such as
NOTIFY_KEY_REVOKED.
n->watch.info & WATCH_INFO_LENGTH will indicate the length of the
record.
n->watch.info & WATCH_INFO_ID will be the second argument to
keyctl_watch_key(), shifted.
n->key will be the ID of the affected key.
n->aux will hold subtype-dependent information, such as the key
being linked into the keyring specified by n->key in the case of
NOTIFY_KEY_LINKED.
Note that it is permissible for event records to be of variable length -
or, at least, the length may be dependent on the subtype. Note also that
the queue can be shared between multiple notifications of various types.
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: James Morris <jamorris@linux.microsoft.com>
-----BEGIN PGP SIGNATURE-----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=vvN4
-----END PGP SIGNATURE-----
Merge tag 'keys-fixes-20200329' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs
Pull keyrings fixes from David Howells:
"Here's a couple of patches that fix a circular dependency between
holding key->sem and mm->mmap_sem when reading data from a key.
One potential issue is that a filesystem looking to use a key inside,
say, ->readpages() could deadlock if the key being read is the key
that's required and the buffer the key is being read into is on a page
that needs to be fetched.
The case actually detected is a bit more involved - with a filesystem
calling request_key() and locking the target keyring for write - which
could be being read"
* tag 'keys-fixes-20200329' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs:
KEYS: Avoid false positive ENOMEM error on key read
KEYS: Don't write out to userspace while holding key semaphore
By allocating a kernel buffer with a user-supplied buffer length, it
is possible that a false positive ENOMEM error may be returned because
the user-supplied length is just too large even if the system do have
enough memory to hold the actual key data.
Moreover, if the buffer length is larger than the maximum amount of
memory that can be returned by kmalloc() (2^(MAX_ORDER-1) number of
pages), a warning message will also be printed.
To reduce this possibility, we set a threshold (PAGE_SIZE) over which we
do check the actual key length first before allocating a buffer of the
right size to hold it. The threshold is arbitrary, it is just used to
trigger a buffer length check. It does not limit the actual key length
as long as there is enough memory to satisfy the memory request.
To further avoid large buffer allocation failure due to page
fragmentation, kvmalloc() is used to allocate the buffer so that vmapped
pages can be used when there is not a large enough contiguous set of
pages available for allocation.
In the extremely unlikely scenario that the key keeps on being changed
and made longer (still <= buflen) in between 2 __keyctl_read_key()
calls, the __keyctl_read_key() calling loop in keyctl_read_key() may
have to be iterated a large number of times, but definitely not infinite.
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Currently, when we add a new user key, the calltrace as below:
add_key()
key_create_or_update()
key_alloc()
__key_instantiate_and_link
generic_key_instantiate
key_payload_reserve
......
Since commit a08bf91ce2 ("KEYS: allow reaching the keys quotas exactly"),
we can reach max bytes/keys in key_alloc, but we forget to remove this
limit when we reserver space for payload in key_payload_reserve. So we
can only reach max keys but not max bytes when having delta between plen
and type->def_datalen. Remove this limit when instantiating the key, so we
can keep consistent with key_alloc.
Also, fix the similar problem in keyctl_chown_key().
Fixes: 0b77f5bfb4 ("keys: make the keyring quotas controllable through /proc/sys")
Fixes: a08bf91ce2 ("KEYS: allow reaching the keys quotas exactly")
Cc: stable@vger.kernel.org # 5.0.x
Cc: Eric Biggers <ebiggers@google.com>
Signed-off-by: Yang Xu <xuyang2018.jy@cn.fujitsu.com>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
-----BEGIN PGP SIGNATURE-----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=E3bF
-----END PGP SIGNATURE-----
Merge tag 'keys-acl-20190703' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs
Pull keyring ACL support from David Howells:
"This changes the permissions model used by keys and keyrings to be
based on an internal ACL by the following means:
- Replace the permissions mask internally with an ACL that contains a
list of ACEs, each with a specific subject with a permissions mask.
Potted default ACLs are available for new keys and keyrings.
ACE subjects can be macroised to indicate the UID and GID specified
on the key (which remain). Future commits will be able to add
additional subject types, such as specific UIDs or domain
tags/namespaces.
Also split a number of permissions to give finer control. Examples
include splitting the revocation permit from the change-attributes
permit, thereby allowing someone to be granted permission to revoke
a key without allowing them to change the owner; also the ability
to join a keyring is split from the ability to link to it, thereby
stopping a process accessing a keyring by joining it and thus
acquiring use of possessor permits.
- Provide a keyctl to allow the granting or denial of one or more
permits to a specific subject. Direct access to the ACL is not
granted, and the ACL cannot be viewed"
* tag 'keys-acl-20190703' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs:
keys: Provide KEYCTL_GRANT_PERMISSION
keys: Replace uid/gid/perm permissions checking with an ACL
-----BEGIN PGP SIGNATURE-----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=Push
-----END PGP SIGNATURE-----
Merge tag 'keys-namespace-20190627' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs
Pull keyring namespacing from David Howells:
"These patches help make keys and keyrings more namespace aware.
Firstly some miscellaneous patches to make the process easier:
- Simplify key index_key handling so that the word-sized chunks
assoc_array requires don't have to be shifted about, making it
easier to add more bits into the key.
- Cache the hash value in the key so that we don't have to calculate
on every key we examine during a search (it involves a bunch of
multiplications).
- Allow keying_search() to search non-recursively.
Then the main patches:
- Make it so that keyring names are per-user_namespace from the point
of view of KEYCTL_JOIN_SESSION_KEYRING so that they're not
accessible cross-user_namespace.
keyctl_capabilities() shows KEYCTL_CAPS1_NS_KEYRING_NAME for this.
- Move the user and user-session keyrings to the user_namespace
rather than the user_struct. This prevents them propagating
directly across user_namespaces boundaries (ie. the KEY_SPEC_*
flags will only pick from the current user_namespace).
- Make it possible to include the target namespace in which the key
shall operate in the index_key. This will allow the possibility of
multiple keys with the same description, but different target
domains to be held in the same keyring.
keyctl_capabilities() shows KEYCTL_CAPS1_NS_KEY_TAG for this.
- Make it so that keys are implicitly invalidated by removal of a
domain tag, causing them to be garbage collected.
- Institute a network namespace domain tag that allows keys to be
differentiated by the network namespace in which they operate. New
keys that are of a type marked 'KEY_TYPE_NET_DOMAIN' are assigned
the network domain in force when they are created.
- Make it so that the desired network namespace can be handed down
into the request_key() mechanism. This allows AFS, NFS, etc. to
request keys specific to the network namespace of the superblock.
This also means that the keys in the DNS record cache are
thenceforth namespaced, provided network filesystems pass the
appropriate network namespace down into dns_query().
For DNS, AFS and NFS are good, whilst CIFS and Ceph are not. Other
cache keyrings, such as idmapper keyrings, also need to set the
domain tag - for which they need access to the network namespace of
the superblock"
* tag 'keys-namespace-20190627' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs:
keys: Pass the network namespace into request_key mechanism
keys: Network namespace domain tag
keys: Garbage collect keys for which the domain has been removed
keys: Include target namespace in match criteria
keys: Move the user and user-session keyrings to the user_namespace
keys: Namespace keyring names
keys: Add a 'recurse' flag for keyring searches
keys: Cache the hash value to avoid lots of recalculation
keys: Simplify key description management
-----BEGIN PGP SIGNATURE-----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=Oy7N
-----END PGP SIGNATURE-----
Merge tag 'keys-misc-20190619' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs
Pull misc keyring updates from David Howells:
"These are some miscellaneous keyrings fixes and improvements:
- Fix a bunch of warnings from sparse, including missing RCU bits and
kdoc-function argument mismatches
- Implement a keyctl to allow a key to be moved from one keyring to
another, with the option of prohibiting key replacement in the
destination keyring.
- Grant Link permission to possessors of request_key_auth tokens so
that upcall servicing daemons can more easily arrange things such
that only the necessary auth key is passed to the actual service
program, and not all the auth keys a daemon might possesss.
- Improvement in lookup_user_key().
- Implement a keyctl to allow keyrings subsystem capabilities to be
queried.
The keyutils next branch has commits to make available, document and
test the move-key and capabilities code:
https://git.kernel.org/pub/scm/linux/kernel/git/dhowells/keyutils.git/log
They're currently on the 'next' branch"
* tag 'keys-misc-20190619' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs:
keys: Add capability-checking keyctl function
keys: Reuse keyring_index_key::desc_len in lookup_user_key()
keys: Grant Link permission to possessers of request_key auth keys
keys: Add a keyctl to move a key between keyrings
keys: Hoist locking out of __key_link_begin()
keys: Break bits out of key_unlink()
keys: Change keyring_serialise_link_sem to a mutex
keys: sparse: Fix kdoc mismatches
keys: sparse: Fix incorrect RCU accesses
keys: sparse: Fix key_fs[ug]id_changed()
Provide a keyctl() operation to grant/remove permissions. The grant
operation, wrapped by libkeyutils, looks like:
int ret = keyctl_grant_permission(key_serial_t key,
enum key_ace_subject_type type,
unsigned int subject,
unsigned int perm);
Where key is the key to be modified, type and subject represent the subject
to which permission is to be granted (or removed) and perm is the set of
permissions to be granted. 0 is returned on success. SET_SECURITY
permission is required for this.
The subject type currently must be KEY_ACE_SUBJ_STANDARD for the moment
(other subject types will come along later).
For subject type KEY_ACE_SUBJ_STANDARD, the following subject values are
available:
KEY_ACE_POSSESSOR The possessor of the key
KEY_ACE_OWNER The owner of the key
KEY_ACE_GROUP The key's group
KEY_ACE_EVERYONE Everyone
perm lists the permissions to be granted:
KEY_ACE_VIEW Can view the key metadata
KEY_ACE_READ Can read the key content
KEY_ACE_WRITE Can update/modify the key content
KEY_ACE_SEARCH Can find the key by searching/requesting
KEY_ACE_LINK Can make a link to the key
KEY_ACE_SET_SECURITY Can set security
KEY_ACE_INVAL Can invalidate
KEY_ACE_REVOKE Can revoke
KEY_ACE_JOIN Can join this keyring
KEY_ACE_CLEAR Can clear this keyring
If an ACE already exists for the subject, then the permissions mask will be
overwritten; if perm is 0, it will be deleted.
Currently, the internal ACL is limited to a maximum of 16 entries.
For example:
int ret = keyctl_grant_permission(key,
KEY_ACE_SUBJ_STANDARD,
KEY_ACE_OWNER,
KEY_ACE_VIEW | KEY_ACE_READ);
Signed-off-by: David Howells <dhowells@redhat.com>
Replace the uid/gid/perm permissions checking on a key with an ACL to allow
the SETATTR and SEARCH permissions to be split. This will also allow a
greater range of subjects to represented.
============
WHY DO THIS?
============
The problem is that SETATTR and SEARCH cover a slew of actions, not all of
which should be grouped together.
For SETATTR, this includes actions that are about controlling access to a
key:
(1) Changing a key's ownership.
(2) Changing a key's security information.
(3) Setting a keyring's restriction.
And actions that are about managing a key's lifetime:
(4) Setting an expiry time.
(5) Revoking a key.
and (proposed) managing a key as part of a cache:
(6) Invalidating a key.
Managing a key's lifetime doesn't really have anything to do with
controlling access to that key.
Expiry time is awkward since it's more about the lifetime of the content
and so, in some ways goes better with WRITE permission. It can, however,
be set unconditionally by a process with an appropriate authorisation token
for instantiating a key, and can also be set by the key type driver when a
key is instantiated, so lumping it with the access-controlling actions is
probably okay.
As for SEARCH permission, that currently covers:
(1) Finding keys in a keyring tree during a search.
(2) Permitting keyrings to be joined.
(3) Invalidation.
But these don't really belong together either, since these actions really
need to be controlled separately.
Finally, there are number of special cases to do with granting the
administrator special rights to invalidate or clear keys that I would like
to handle with the ACL rather than key flags and special checks.
===============
WHAT IS CHANGED
===============
The SETATTR permission is split to create two new permissions:
(1) SET_SECURITY - which allows the key's owner, group and ACL to be
changed and a restriction to be placed on a keyring.
(2) REVOKE - which allows a key to be revoked.
The SEARCH permission is split to create:
(1) SEARCH - which allows a keyring to be search and a key to be found.
(2) JOIN - which allows a keyring to be joined as a session keyring.
(3) INVAL - which allows a key to be invalidated.
The WRITE permission is also split to create:
(1) WRITE - which allows a key's content to be altered and links to be
added, removed and replaced in a keyring.
(2) CLEAR - which allows a keyring to be cleared completely. This is
split out to make it possible to give just this to an administrator.
(3) REVOKE - see above.
Keys acquire ACLs which consist of a series of ACEs, and all that apply are
unioned together. An ACE specifies a subject, such as:
(*) Possessor - permitted to anyone who 'possesses' a key
(*) Owner - permitted to the key owner
(*) Group - permitted to the key group
(*) Everyone - permitted to everyone
Note that 'Other' has been replaced with 'Everyone' on the assumption that
you wouldn't grant a permit to 'Other' that you wouldn't also grant to
everyone else.
Further subjects may be made available by later patches.
The ACE also specifies a permissions mask. The set of permissions is now:
VIEW Can view the key metadata
READ Can read the key content
WRITE Can update/modify the key content
SEARCH Can find the key by searching/requesting
LINK Can make a link to the key
SET_SECURITY Can change owner, ACL, expiry
INVAL Can invalidate
REVOKE Can revoke
JOIN Can join this keyring
CLEAR Can clear this keyring
The KEYCTL_SETPERM function is then deprecated.
The KEYCTL_SET_TIMEOUT function then is permitted if SET_SECURITY is set,
or if the caller has a valid instantiation auth token.
The KEYCTL_INVALIDATE function then requires INVAL.
The KEYCTL_REVOKE function then requires REVOKE.
The KEYCTL_JOIN_SESSION_KEYRING function then requires JOIN to join an
existing keyring.
The JOIN permission is enabled by default for session keyrings and manually
created keyrings only.
======================
BACKWARD COMPATIBILITY
======================
To maintain backward compatibility, KEYCTL_SETPERM will translate the
permissions mask it is given into a new ACL for a key - unless
KEYCTL_SET_ACL has been called on that key, in which case an error will be
returned.
It will convert possessor, owner, group and other permissions into separate
ACEs, if each portion of the mask is non-zero.
SETATTR permission turns on all of INVAL, REVOKE and SET_SECURITY. WRITE
permission turns on WRITE, REVOKE and, if a keyring, CLEAR. JOIN is turned
on if a keyring is being altered.
The KEYCTL_DESCRIBE function translates the ACL back into a permissions
mask to return depending on possessor, owner, group and everyone ACEs.
It will make the following mappings:
(1) INVAL, JOIN -> SEARCH
(2) SET_SECURITY -> SETATTR
(3) REVOKE -> WRITE if SETATTR isn't already set
(4) CLEAR -> WRITE
Note that the value subsequently returned by KEYCTL_DESCRIBE may not match
the value set with KEYCTL_SETATTR.
=======
TESTING
=======
This passes the keyutils testsuite for all but a couple of tests:
(1) tests/keyctl/dh_compute/badargs: The first wrong-key-type test now
returns EOPNOTSUPP rather than ENOKEY as READ permission isn't removed
if the type doesn't have ->read(). You still can't actually read the
key.
(2) tests/keyctl/permitting/valid: The view-other-permissions test doesn't
work as Other has been replaced with Everyone in the ACL.
Signed-off-by: David Howells <dhowells@redhat.com>
Currently a key has a standard matching criteria of { type, description }
and this is used to only allow keys with unique criteria in a keyring.
This means, however, that you cannot have keys with the same type and
description but a different target namespace in the same keyring.
This is a potential problem for a containerised environment where, say, a
container is made up of some parts of its mount space involving netfs
superblocks from two different network namespaces.
This is also a problem for shared system management keyrings such as the
DNS records keyring or the NFS idmapper keyring that might contain keys
from different network namespaces.
Fix this by including a namespace component in a key's matching criteria.
Keyring types are marked to indicate which, if any, namespace is relevant
to keys of that type, and that namespace is set when the key is created
from the current task's namespace set.
The capability bit KEYCTL_CAPS1_NS_KEY_TAG is set if the kernel is
employing this feature.
Signed-off-by: David Howells <dhowells@redhat.com>
Keyring names are held in a single global list that any process can pick
from by means of keyctl_join_session_keyring (provided the keyring grants
Search permission). This isn't very container friendly, however.
Make the following changes:
(1) Make default session, process and thread keyring names begin with a
'.' instead of '_'.
(2) Keyrings whose names begin with a '.' aren't added to the list. Such
keyrings are system specials.
(3) Replace the global list with per-user_namespace lists. A keyring adds
its name to the list for the user_namespace that it is currently in.
(4) When a user_namespace is deleted, it just removes itself from the
keyring name list.
The global keyring_name_lock is retained for accessing the name lists.
This allows (4) to work.
This can be tested by:
# keyctl newring foo @s
995906392
# unshare -U
$ keyctl show
...
995906392 --alswrv 65534 65534 \_ keyring: foo
...
$ keyctl session foo
Joined session keyring: 935622349
As can be seen, a new session keyring was created.
The capability bit KEYCTL_CAPS1_NS_KEYRING_NAME is set if the kernel is
employing this feature.
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Eric W. Biederman <ebiederm@xmission.com>
Add a 'recurse' flag for keyring searches so that the flag can be omitted
and recursion disabled, thereby allowing just the nominated keyring to be
searched and none of the children.
Signed-off-by: David Howells <dhowells@redhat.com>
Add a keyctl function that requests a set of capability bits to find out
what features are supported.
Signed-off-by: David Howells <dhowells@redhat.com>
Add a keyctl to atomically move a link to a key from one keyring to
another. The key must exist in "from" keyring and a flag can be given to
cause the operation to fail if there's a matching key already in the "to"
keyring.
This can be done with:
keyctl(KEYCTL_MOVE,
key_serial_t key,
key_serial_t from_keyring,
key_serial_t to_keyring,
unsigned int flags);
The key being moved must grant Link permission and both keyrings must grant
Write permission.
flags should be 0 or KEYCTL_MOVE_EXCL, with the latter preventing
displacement of a matching key from the "to" keyring.
Signed-off-by: David Howells <dhowells@redhat.com>
Based on 1 normalized pattern(s):
this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation either version 2 of the license or at
your option any later version
extracted by the scancode license scanner the SPDX license identifier
GPL-2.0-or-later
has been chosen to replace the boilerplate/reference in 3029 file(s).
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Fix a pair of accesses that should be using RCU protection.
rcu_dereference_protected() is needed to access task_struct::real_parent.
current_cred() should be used to access current->cred.
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: James Morris <jamorris@linux.microsoft.com>
Pull security subsystem updates from James Morris:
- Extend LSM stacking to allow sharing of cred, file, ipc, inode, and
task blobs. This paves the way for more full-featured LSMs to be
merged, and is specifically aimed at LandLock and SARA LSMs. This
work is from Casey and Kees.
- There's a new LSM from Micah Morton: "SafeSetID gates the setid
family of syscalls to restrict UID/GID transitions from a given
UID/GID to only those approved by a system-wide whitelist." This
feature is currently shipping in ChromeOS.
* 'next-general' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security: (62 commits)
keys: fix missing __user in KEYCTL_PKEY_QUERY
LSM: Update list of SECURITYFS users in Kconfig
LSM: Ignore "security=" when "lsm=" is specified
LSM: Update function documentation for cap_capable
security: mark expected switch fall-throughs and add a missing break
tomoyo: Bump version.
LSM: fix return value check in safesetid_init_securityfs()
LSM: SafeSetID: add selftest
LSM: SafeSetID: remove unused include
LSM: SafeSetID: 'depend' on CONFIG_SECURITY
LSM: Add 'name' field for SafeSetID in DEFINE_LSM
LSM: add SafeSetID module that gates setid calls
LSM: add SafeSetID module that gates setid calls
tomoyo: Allow multiple use_group lines.
tomoyo: Coding style fix.
tomoyo: Swicth from cred->security to task_struct->security.
security: keys: annotate implicit fall throughs
security: keys: annotate implicit fall throughs
security: keys: annotate implicit fall through
capabilities:: annotate implicit fall through
...
The arg5 of KEYCTL_PKEY_QUERY should have a __user pointer tag on
it as it is a user pointer. This clears the following sparse warning
for this:
security/keys/keyctl.c:1755:43: warning: incorrect type in argument 3 (different address spaces)
security/keys/keyctl.c:1755:43: expected struct keyctl_pkey_query [noderef] <asn:1>*<noident>
security/keys/keyctl.c:1755:43: got struct keyctl_pkey_query *<noident>
Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
Acked-by: Serge Hallyn <serge@hallyn.com>
Signed-off-by: James Morris <james.morris@microsoft.com>
In the request_key() upcall mechanism there's a dependency loop by which if
a key type driver overrides the ->request_key hook and the userspace side
manages to lose the authorisation key, the auth key and the internal
construction record (struct key_construction) can keep each other pinned.
Fix this by the following changes:
(1) Killing off the construction record and using the auth key instead.
(2) Including the operation name in the auth key payload and making the
payload available outside of security/keys/.
(3) The ->request_key hook is given the authkey instead of the cons
record and operation name.
Changes (2) and (3) allow the auth key to naturally be cleaned up if the
keyring it is in is destroyed or cleared or the auth key is unlinked.
Fixes: 7ee02a316600 ("keys: Fix dependency loop between construction record and auth key")
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <james.morris@microsoft.com>
Historically a lot of these existed because we did not have
a distinction between what was modular code and what was providing
support to modules via EXPORT_SYMBOL and friends. That changed
when we forked out support for the latter into the export.h file.
This means we should be able to reduce the usage of module.h
in code that is obj-y Makefile or bool Kconfig.
The advantage in removing such instances is that module.h itself
sources about 15 other headers; adding significantly to what we feed
cpp, and it can obscure what headers we are effectively using.
Since module.h might have been the implicit source for init.h
(for __init) and for export.h (for EXPORT_SYMBOL) we consider each
instance for the presence of either and replace as needed.
Cc: James Morris <jmorris@namei.org>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Cc: John Johansen <john.johansen@canonical.com>
Cc: Mimi Zohar <zohar@linux.ibm.com>
Cc: Dmitry Kasatkin <dmitry.kasatkin@gmail.com>
Cc: David Howells <dhowells@redhat.com>
Cc: linux-security-module@vger.kernel.org
Cc: linux-integrity@vger.kernel.org
Cc: keyrings@vger.kernel.org
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: James Morris <james.morris@microsoft.com>
Provide five keyctl functions that permit userspace to make use of the new
key type ops for accessing and driving asymmetric keys.
(*) Query an asymmetric key.
long keyctl(KEYCTL_PKEY_QUERY,
key_serial_t key, unsigned long reserved,
struct keyctl_pkey_query *info);
Get information about an asymmetric key. The information is returned
in the keyctl_pkey_query struct:
__u32 supported_ops;
A bit mask of flags indicating which ops are supported. This is
constructed from a bitwise-OR of:
KEYCTL_SUPPORTS_{ENCRYPT,DECRYPT,SIGN,VERIFY}
__u32 key_size;
The size in bits of the key.
__u16 max_data_size;
__u16 max_sig_size;
__u16 max_enc_size;
__u16 max_dec_size;
The maximum sizes in bytes of a blob of data to be signed, a signature
blob, a blob to be encrypted and a blob to be decrypted.
reserved must be set to 0. This is intended for future use to hand
over one or more passphrases needed unlock a key.
If successful, 0 is returned. If the key is not an asymmetric key,
EOPNOTSUPP is returned.
(*) Encrypt, decrypt, sign or verify a blob using an asymmetric key.
long keyctl(KEYCTL_PKEY_ENCRYPT,
const struct keyctl_pkey_params *params,
const char *info,
const void *in,
void *out);
long keyctl(KEYCTL_PKEY_DECRYPT,
const struct keyctl_pkey_params *params,
const char *info,
const void *in,
void *out);
long keyctl(KEYCTL_PKEY_SIGN,
const struct keyctl_pkey_params *params,
const char *info,
const void *in,
void *out);
long keyctl(KEYCTL_PKEY_VERIFY,
const struct keyctl_pkey_params *params,
const char *info,
const void *in,
const void *in2);
Use an asymmetric key to perform a public-key cryptographic operation
a blob of data.
The parameter block pointed to by params contains a number of integer
values:
__s32 key_id;
__u32 in_len;
__u32 out_len;
__u32 in2_len;
For a given operation, the in and out buffers are used as follows:
Operation ID in,in_len out,out_len in2,in2_len
======================= =============== =============== ===========
KEYCTL_PKEY_ENCRYPT Raw data Encrypted data -
KEYCTL_PKEY_DECRYPT Encrypted data Raw data -
KEYCTL_PKEY_SIGN Raw data Signature -
KEYCTL_PKEY_VERIFY Raw data - Signature
info is a string of key=value pairs that supply supplementary
information.
The __spare space in the parameter block must be set to 0. This is
intended, amongst other things, to allow the passing of passphrases
required to unlock a key.
If successful, encrypt, decrypt and sign all return the amount of data
written into the output buffer. Verification returns 0 on success.
Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: Marcel Holtmann <marcel@holtmann.org>
Reviewed-by: Marcel Holtmann <marcel@holtmann.org>
Reviewed-by: Denis Kenzior <denkenz@gmail.com>
Tested-by: Denis Kenzior <denkenz@gmail.com>
Signed-off-by: James Morris <james.morris@microsoft.com>
keyctl_restrict_keyring() allows through a NULL restriction when the
"type" is non-NULL, which causes a NULL pointer dereference in
asymmetric_lookup_restriction() when it calls strcmp() on the
restriction string.
But no key types actually use a "NULL restriction" to mean anything, so
update keyctl_restrict_keyring() to reject it with EINVAL.
Reported-by: syzbot <syzkaller@googlegroups.com>
Fixes: 97d3aa0f31 ("KEYS: Add a lookup_restriction function for the asymmetric key type")
Cc: <stable@vger.kernel.org> # v4.12+
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Consolidate KEY_FLAG_INSTANTIATED, KEY_FLAG_NEGATIVE and the rejection
error into one field such that:
(1) The instantiation state can be modified/read atomically.
(2) The error can be accessed atomically with the state.
(3) The error isn't stored unioned with the payload pointers.
This deals with the problem that the state is spread over three different
objects (two bits and a separate variable) and reading or updating them
atomically isn't practical, given that not only can uninstantiated keys
change into instantiated or rejected keys, but rejected keys can also turn
into instantiated keys - and someone accessing the key might not be using
any locking.
The main side effect of this problem is that what was held in the payload
may change, depending on the state. For instance, you might observe the
key to be in the rejected state. You then read the cached error, but if
the key semaphore wasn't locked, the key might've become instantiated
between the two reads - and you might now have something in hand that isn't
actually an error code.
The state is now KEY_IS_UNINSTANTIATED, KEY_IS_POSITIVE or a negative error
code if the key is negatively instantiated. The key_is_instantiated()
function is replaced with key_is_positive() to avoid confusion as negative
keys are also 'instantiated'.
Additionally, barriering is included:
(1) Order payload-set before state-set during instantiation.
(2) Order state-read before payload-read when using the key.
Further separate barriering is necessary if RCU is being used to access the
payload content after reading the payload pointers.
Fixes: 146aa8b145 ("KEYS: Merge the type-specific data with the payload data")
Cc: stable@vger.kernel.org # v4.4+
Reported-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Eric Biggers <ebiggers@google.com>
In keyctl_read_key(), if key_permission() were to return an error code
other than EACCES, we would leak a the reference to the key. This can't
actually happen currently because key_permission() can only return an
error code other than EACCES if security_key_permission() does, only
SELinux and Smack implement that hook, and neither can return an error
code other than EACCES. But it should still be fixed, as it is a bug
waiting to happen.
Fixes: 29db919063 ("[PATCH] Keys: Add LSM hooks for key management [try #3]")
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: David Howells <dhowells@redhat.com>
In keyctl_assume_authority(), if keyctl_change_reqkey_auth() were to
fail, we would leak the reference to the 'authkey'. Currently this can
only happen if prepare_creds() fails to allocate memory. But it still
should be fixed, as it is a more severe bug waiting to happen.
This patch also moves the read of 'authkey->serial' to before the
reference to the authkey is dropped. Doing the read after dropping the
reference is very fragile because it assumes we still hold another
reference to the key. (Which we do, in current->cred->request_key_auth,
but there's no reason not to write it in the "obviously correct" way.)
Fixes: d84f4f992c ("CRED: Inaugurate COW credentials")
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Before returning from add_key() or one of the keyctl() commands that
takes in a key payload, zero the temporary buffer that was allocated to
hold the key payload copied from userspace. This may contain sensitive
key material that should not be kept around in the slab caches.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>
sys_add_key() and the KEYCTL_UPDATE operation of sys_keyctl() allowed a
NULL payload with nonzero length to be passed to the key type's
->preparse(), ->instantiate(), and/or ->update() methods. Various key
types including asymmetric, cifs.idmap, cifs.spnego, and pkcs7_test did
not handle this case, allowing an unprivileged user to trivially cause a
NULL pointer dereference (kernel oops) if one of these key types was
present. Fix it by doing the copy_from_user() when 'plen' is nonzero
rather than when '_payload' is non-NULL, causing the syscall to fail
with EFAULT as expected when an invalid buffer is specified.
Cc: stable@vger.kernel.org # 2.6.10+
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>
There are many code paths opencoding kvmalloc. Let's use the helper
instead. The main difference to kvmalloc is that those users are
usually not considering all the aspects of the memory allocator. E.g.
allocation requests <= 32kB (with 4kB pages) are basically never failing
and invoke OOM killer to satisfy the allocation. This sounds too
disruptive for something that has a reasonable fallback - the vmalloc.
On the other hand those requests might fallback to vmalloc even when the
memory allocator would succeed after several more reclaim/compaction
attempts previously. There is no guarantee something like that happens
though.
This patch converts many of those places to kv[mz]alloc* helpers because
they are more conservative.
Link: http://lkml.kernel.org/r/20170306103327.2766-2-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> # Xen bits
Acked-by: Kees Cook <keescook@chromium.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Andreas Dilger <andreas.dilger@intel.com> # Lustre
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com> # KVM/s390
Acked-by: Dan Williams <dan.j.williams@intel.com> # nvdim
Acked-by: David Sterba <dsterba@suse.com> # btrfs
Acked-by: Ilya Dryomov <idryomov@gmail.com> # Ceph
Acked-by: Tariq Toukan <tariqt@mellanox.com> # mlx4
Acked-by: Leon Romanovsky <leonro@mellanox.com> # mlx5
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Anton Vorontsov <anton@enomsg.org>
Cc: Colin Cross <ccross@android.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Cc: Santosh Raspatur <santosh@chelsio.com>
Cc: Hariprasad S <hariprasad@chelsio.com>
Cc: Yishai Hadas <yishaih@mellanox.com>
Cc: Oleg Drokin <oleg.drokin@intel.com>
Cc: "Yan, Zheng" <zyan@redhat.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: David Miller <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull security subsystem updates from James Morris:
"Highlights:
IMA:
- provide ">" and "<" operators for fowner/uid/euid rules
KEYS:
- add a system blacklist keyring
- add KEYCTL_RESTRICT_KEYRING, exposes keyring link restriction
functionality to userland via keyctl()
LSM:
- harden LSM API with __ro_after_init
- add prlmit security hook, implement for SELinux
- revive security_task_alloc hook
TPM:
- implement contextual TPM command 'spaces'"
* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security: (98 commits)
tpm: Fix reference count to main device
tpm_tis: convert to using locality callbacks
tpm: fix handling of the TPM 2.0 event logs
tpm_crb: remove a cruft constant
keys: select CONFIG_CRYPTO when selecting DH / KDF
apparmor: Make path_max parameter readonly
apparmor: fix parameters so that the permission test is bypassed at boot
apparmor: fix invalid reference to index variable of iterator line 836
apparmor: use SHASH_DESC_ON_STACK
security/apparmor/lsm.c: set debug messages
apparmor: fix boolreturn.cocci warnings
Smack: Use GFP_KERNEL for smk_netlbl_mls().
smack: fix double free in smack_parse_opts_str()
KEYS: add SP800-56A KDF support for DH
KEYS: Keyring asymmetric key restrict method with chaining
KEYS: Restrict asymmetric key linkage using a specific keychain
KEYS: Add a lookup_restriction function for the asymmetric key type
KEYS: Add KEYCTL_RESTRICT_KEYRING
KEYS: Consistent ordering for __key_link_begin and restrict check
KEYS: Add an optional lookup_restriction hook to key_type
...
This fixes CVE-2017-7472.
Running the following program as an unprivileged user exhausts kernel
memory by leaking thread keyrings:
#include <keyutils.h>
int main()
{
for (;;)
keyctl_set_reqkey_keyring(KEY_REQKEY_DEFL_THREAD_KEYRING);
}
Fix it by only creating a new thread keyring if there wasn't one before.
To make things more consistent, make install_thread_keyring_to_cred()
and install_process_keyring_to_cred() both return 0 if the corresponding
keyring is already present.
Fixes: d84f4f992c ("CRED: Inaugurate COW credentials")
Cc: stable@vger.kernel.org # 2.6.29+
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: David Howells <dhowells@redhat.com>
This fixes CVE-2016-9604.
Keyrings whose name begin with a '.' are special internal keyrings and so
userspace isn't allowed to create keyrings by this name to prevent
shadowing. However, the patch that added the guard didn't fix
KEYCTL_JOIN_SESSION_KEYRING. Not only can that create dot-named keyrings,
it can also subscribe to them as a session keyring if they grant SEARCH
permission to the user.
This, for example, allows a root process to set .builtin_trusted_keys as
its session keyring, at which point it has full access because now the
possessor permissions are added. This permits root to add extra public
keys, thereby bypassing module verification.
This also affects kexec and IMA.
This can be tested by (as root):
keyctl session .builtin_trusted_keys
keyctl add user a a @s
keyctl list @s
which on my test box gives me:
2 keys in keyring:
180010936: ---lswrv 0 0 asymmetric: Build time autogenerated kernel key: ae3d4a31b82daa8e1a75b49dc2bba949fd992a05
801382539: --alswrv 0 0 user: a
Fix this by rejecting names beginning with a '.' in the keyctl.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
cc: linux-ima-devel@lists.sourceforge.net
cc: stable@vger.kernel.org
SP800-56A defines the use of DH with key derivation function based on a
counter. The input to the KDF is defined as (DH shared secret || other
information). The value for the "other information" is to be provided by
the caller.
The KDF is implemented using the hash support from the kernel crypto API.
The implementation uses the symmetric hash support as the input to the
hash operation is usually very small. The caller is allowed to specify
the hash name that he wants to use to derive the key material allowing
the use of all supported hashes provided with the kernel crypto API.
As the KDF implements the proper truncation of the DH shared secret to
the requested size, this patch fills the caller buffer up to its size.
The patch is tested with a new test added to the keyutils user space
code which uses a CAVS test vector testing the compliance with
SP800-56A.
Signed-off-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: David Howells <dhowells@redhat.com>
Keyrings recently gained restrict_link capabilities that allow
individual keys to be validated prior to linking. This functionality
was only available using internal kernel APIs.
With the KEYCTL_RESTRICT_KEYRING command existing keyrings can be
configured to check the content of keys before they are linked, and
then allow or disallow linkage of that key to the keyring.
To restrict a keyring, call:
keyctl(KEYCTL_RESTRICT_KEYRING, key_serial_t keyring, const char *type,
const char *restriction)
where 'type' is the name of a registered key type and 'restriction' is a
string describing how key linkage is to be restricted. The restriction
option syntax is specific to each key type.
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
We are going to split <linux/sched/task.h> out of <linux/sched.h>, which
will have to be picked up from other headers and a couple of .c files.
Create a trivial placeholder <linux/sched/task.h> file that just
maps to <linux/sched.h> to make this patch obviously correct and
bisectable.
Include the new header in the files that are going to need it.
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Add #include <linux/cred.h> dependencies to all .c files rely on sched.h
doing that for them.
Note that even if the count where we need to add extra headers seems high,
it's still a net win, because <linux/sched.h> is included in over
2,200 files ...
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This was entirely automated, using the script by Al:
PATT='^[[:blank:]]*#[[:blank:]]*include[[:blank:]]*<asm/uaccess.h>'
sed -i -e "s!$PATT!#include <linux/uaccess.h>!" \
$(git grep -l "$PATT"|grep -v ^include/linux/uaccess.h)
to do the replacement at the end of the merge window.
Requested-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
copy_from_iter_full(), copy_from_iter_full_nocache() and
csum_and_copy_from_iter_full() - counterparts of copy_from_iter()
et.al., advancing iterator only in case of successful full copy
and returning whether it had been successful or not.
Convert some obvious users. *NOTE* - do not blindly assume that
something is a good candidate for those unless you are sure that
not advancing iov_iter in failure case is the right thing in
this case. Anything that does short read/short write kind of
stuff (or is in a loop, etc.) is unlikely to be a good one.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
The values computed during Diffie-Hellman key exchange are often used
in combination with key derivation functions to create cryptographic
keys. Add a placeholder for a later implementation to configure a
key derivation function that will transform the Diffie-Hellman
result returned by the KEYCTL_DH_COMPUTE command.
[This patch was stripped down from a patch produced by Mat Martineau that
had a bug in the compat code - so for the moment Stephan's patch simply
requires that the placeholder argument must be NULL]
Original-signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>
This adds userspace access to Diffie-Hellman computations through a
new keyctl() syscall command to calculate shared secrets or public
keys using input parameters stored in the keyring.
Input key ids are provided in a struct due to the current 5-arg limit
for the keyctl syscall. Only user keys are supported in order to avoid
exposing the content of logon or encrypted keys.
The output is written to the provided buffer, based on the assumption
that the values are only needed in userspace.
Future support for other types of key derivation would involve a new
command, like KEYCTL_ECDH_COMPUTE.
Once Diffie-Hellman support is included in the crypto API, this code
can be converted to use the crypto API to take advantage of possible
hardware acceleration and reduce redundant code.
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Pull security subsystem updates from James Morris:
- EVM gains support for loading an x509 cert from the kernel
(EVM_LOAD_X509), into the EVM trusted kernel keyring.
- Smack implements 'file receive' process-based permission checking for
sockets, rather than just depending on inode checks.
- Misc enhancments for TPM & TPM2.
- Cleanups and bugfixes for SELinux, Keys, and IMA.
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security: (41 commits)
selinux: Inode label revalidation performance fix
KEYS: refcount bug fix
ima: ima_write_policy() limit locking
IMA: policy can be updated zero times
selinux: rate-limit netlink message warnings in selinux_nlmsg_perm()
selinux: export validatetrans decisions
gfs2: Invalid security labels of inodes when they go invalid
selinux: Revalidate invalid inode security labels
security: Add hook to invalidate inode security labels
selinux: Add accessor functions for inode->i_security
security: Make inode argument of inode_getsecid non-const
security: Make inode argument of inode_getsecurity non-const
selinux: Remove unused variable in selinux_inode_init_security
keys, trusted: seal with a TPM2 authorization policy
keys, trusted: select hash algorithm for TPM2 chips
keys, trusted: fix: *do not* allow duplicate key options
tpm_ibmvtpm: properly handle interrupted packet receptions
tpm_tis: Tighten IRQ auto-probing
tpm_tis: Refactor the interrupt setup
tpm_tis: Get rid of the duplicate IRQ probing code
...
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:
d3600bc KEYS: prevent keys from being removed from specified keyrings
Reported-by: David Howells <dhowells@redhat.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Acked-by: David Howells <dhowells@redhat.com>
This fixes CVE-2015-7550.
There's a race between keyctl_read() and keyctl_revoke(). If the revoke
happens between keyctl_read() checking the validity of a key and the key's
semaphore being taken, then the key type read method will see a revoked key.
This causes a problem for the user-defined key type because it assumes in
its read method that there will always be a payload in a non-revoked key
and doesn't check for a NULL pointer.
Fix this by making keyctl_read() check the validity of a key after taking
semaphore instead of before.
I think the bug was introduced with the original keyrings code.
This was discovered by a multithreaded test program generated by syzkaller
(http://github.com/google/syzkaller). Here's a cleaned up version:
#include <sys/types.h>
#include <keyutils.h>
#include <pthread.h>
void *thr0(void *arg)
{
key_serial_t key = (unsigned long)arg;
keyctl_revoke(key);
return 0;
}
void *thr1(void *arg)
{
key_serial_t key = (unsigned long)arg;
char buffer[16];
keyctl_read(key, buffer, 16);
return 0;
}
int main()
{
key_serial_t key = add_key("user", "%", "foo", 3, KEY_SPEC_USER_KEYRING);
pthread_t th[5];
pthread_create(&th[0], 0, thr0, (void *)(unsigned long)key);
pthread_create(&th[1], 0, thr1, (void *)(unsigned long)key);
pthread_create(&th[2], 0, thr0, (void *)(unsigned long)key);
pthread_create(&th[3], 0, thr1, (void *)(unsigned long)key);
pthread_join(th[0], 0);
pthread_join(th[1], 0);
pthread_join(th[2], 0);
pthread_join(th[3], 0);
return 0;
}
Build as:
cc -o keyctl-race keyctl-race.c -lkeyutils -lpthread
Run as:
while keyctl-race; do :; done
as it may need several iterations to crash the kernel. The crash can be
summarised as:
BUG: unable to handle kernel NULL pointer dereference at 0000000000000010
IP: [<ffffffff81279b08>] user_read+0x56/0xa3
...
Call Trace:
[<ffffffff81276aa9>] keyctl_read_key+0xb6/0xd7
[<ffffffff81277815>] SyS_keyctl+0x83/0xe0
[<ffffffff815dbb97>] entry_SYSCALL_64_fastpath+0x12/0x6f
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: Dmitry Vyukov <dvyukov@google.com>
Cc: stable@vger.kernel.org
Signed-off-by: James Morris <james.l.morris@oracle.com>
