When a key is being garbage collected, it's key->user would get put before
the ->destroy() callback is called, where the key is removed from it's
respective tracking structures.
This leaves a key hanging in a semi-invalid state which leaves a window open
for a different task to try an access key->user. An example is
find_keyring_by_name() which would dereference key->user for a key that is
in the process of being garbage collected (where key->user was freed but
->destroy() wasn't called yet - so it's still present in the linked list).
This would cause either a panic, or corrupt memory.
Fixes CVE-2014-9529.
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: David 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: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>
Pull security layer updates from James Morris:
"In terms of changes, there's general maintenance to the Smack,
SELinux, and integrity code.
The IMA code adds a new kconfig option, IMA_APPRAISE_SIGNED_INIT,
which allows IMA appraisal to require signatures. Support for reading
keys from rootfs before init is call is also added"
* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security: (23 commits)
selinux: Remove security_ops extern
security: smack: fix out-of-bounds access in smk_parse_smack()
VFS: refactor vfs_read()
ima: require signature based appraisal
integrity: provide a hook to load keys when rootfs is ready
ima: load x509 certificate from the kernel
integrity: provide a function to load x509 certificate from the kernel
integrity: define a new function integrity_read_file()
Security: smack: replace kzalloc with kmem_cache for inode_smack
Smack: Lock mode for the floor and hat labels
ima: added support for new kernel cmdline parameter ima_template_fmt
ima: allocate field pointers array on demand in template_desc_init_fields()
ima: don't allocate a copy of template_fmt in template_desc_init_fields()
ima: display template format in meas. list if template name length is zero
ima: added error messages to template-related functions
ima: use atomic bit operations to protect policy update interface
ima: ignore empty and with whitespaces policy lines
ima: no need to allocate entry for comment
ima: report policy load status
ima: use path names cache
...
Pull VFS changes from Al Viro:
"First pile out of several (there _definitely_ will be more). Stuff in
this one:
- unification of d_splice_alias()/d_materialize_unique()
- iov_iter rewrite
- killing a bunch of ->f_path.dentry users (and f_dentry macro).
Getting that completed will make life much simpler for
unionmount/overlayfs, since then we'll be able to limit the places
sensitive to file _dentry_ to reasonably few. Which allows to have
file_inode(file) pointing to inode in a covered layer, with dentry
pointing to (negative) dentry in union one.
Still not complete, but much closer now.
- crapectomy in lustre (dead code removal, mostly)
- "let's make seq_printf return nothing" preparations
- assorted cleanups and fixes
There _definitely_ will be more piles"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (63 commits)
copy_from_iter_nocache()
new helper: iov_iter_kvec()
csum_and_copy_..._iter()
iov_iter.c: handle ITER_KVEC directly
iov_iter.c: convert copy_to_iter() to iterate_and_advance
iov_iter.c: convert copy_from_iter() to iterate_and_advance
iov_iter.c: get rid of bvec_copy_page_{to,from}_iter()
iov_iter.c: convert iov_iter_zero() to iterate_and_advance
iov_iter.c: convert iov_iter_get_pages_alloc() to iterate_all_kinds
iov_iter.c: convert iov_iter_get_pages() to iterate_all_kinds
iov_iter.c: convert iov_iter_npages() to iterate_all_kinds
iov_iter.c: iterate_and_advance
iov_iter.c: macros for iterating over iov_iter
kill f_dentry macro
dcache: fix kmemcheck warning in switch_names
new helper: audit_file()
nfsd_vfs_write(): use file_inode()
ncpfs: use file_inode()
kill f_dentry uses
lockd: get rid of ->f_path.dentry->d_sb
...
On powerpc we can end up with IMA=y and PPC_PSERIES=n which leads to:
warning: (IMA) selects TCG_IBMVTPM which has unmet direct dependencies (TCG_TPM && PPC_PSERIES)
tpm_ibmvtpm.c:(.text+0x14f3e8): undefined reference to `.plpar_hcall_norets'
I'm not sure why IMA needs to select those user-visible symbols, but if
it must then the simplest fix is to just express the proper dependencies
on the select.
Tested-by: Hon Ching (Vicky) Lo <lo1@us.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
When loading encrypted-keys module, if the last check of
aes_get_sizes() in init_encrypted() fails, the driver just returns an
error without unregistering its key type. This results in the stale
entry in the list. In addition to memory leaks, this leads to a kernel
crash when registering a new key type later.
This patch fixes the problem by swapping the calls of aes_get_sizes()
and register_key_type(), and releasing resources properly at the error
paths.
Bugzilla: https://bugzilla.opensuse.org/show_bug.cgi?id=908163
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Since the keyring facility can be viewed as a cache (at least in some
applications), the local expiration time on the key should probably be viewed
as a 'needs updating after this time' property rather than an absolute 'anyone
now wanting to use this object is out of luck' property.
Since request_key() is the main interface for the usage of keys, this should
update or replace an expired key rather than issuing EKEYEXPIRED if the local
expiration has been reached (ie. it should refresh the cache).
For absolute conditions where refreshing the cache probably doesn't help, the
key can be negatively instantiated using KEYCTL_REJECT_KEY with EKEYEXPIRED
given as the error to issue. This will still cause request_key() to return
EKEYEXPIRED as that was explicitly set.
In the future, if the key type has an update op available, we might want to
upcall with the expired key and allow the upcall to update it. We would pass
a different operation name (the first column in /etc/request-key.conf) to the
request-key program.
request_key() returning EKEYEXPIRED is causing an NFS problem which Chuck
Lever describes thusly:
After about 10 minutes, my NFSv4 functional tests fail because the
ownership of the test files goes to "-2". Looking at /proc/keys
shows that the id_resolv keys that map to my test user ID have
expired. The ownership problem persists until the expired keys are
purged from the keyring, and fresh keys are obtained.
I bisected the problem to 3.13 commit b2a4df200d ("KEYS: Expand
the capacity of a keyring"). This commit inadvertantly changes the
API contract of the internal function keyring_search_aux().
The root cause appears to be that b2a4df200d made "no state check"
the default behavior. "No state check" means the keyring search
iterator function skips checking the key's expiry timeout, and
returns expired keys. request_key_and_link() depends on getting
an -EAGAIN result code to know when to perform an upcall to refresh
an expired key.
This patch can be tested directly by:
keyctl request2 user debug:fred a @s
keyctl timeout %user:debug:fred 3
sleep 4
keyctl request2 user debug:fred a @s
Without the patch, the last command gives error EKEYEXPIRED, but with the
command it gives a new key.
Reported-by: Carl Hetherington <cth@carlh.net>
Reported-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: Chuck Lever <chuck.lever@oracle.com>
Simplify KEYRING_SEARCH_{NO,DO}_STATE_CHECK flags to be two variations of the
same flag. They are effectively mutually exclusive and one or the other
should be provided, but not both.
Keyring cycle detection and key possession determination are the only things
that set NO_STATE_CHECK, except that neither flag really does anything there
because neither purpose makes use of the keyring_search_iterator() function,
but rather provides their own.
For cycle detection we definitely want to check inside of expired keyrings,
just so that we don't create a cycle we can't get rid of. Revoked keyrings
are cleared at revocation time and can't then be reused, so shouldn't be a
problem either way.
For possession determination, we *might* want to validate each keyring before
searching it: do you possess a key that's hidden behind an expired or just
plain inaccessible keyring? Currently, the answer is yes. Note that you
cannot, however, possess a key behind a revoked keyring because they are
cleared on revocation.
keyring_search() sets DO_STATE_CHECK, which is correct.
request_key_and_link() currently doesn't specify whether to check the key
state or not - but it should set DO_STATE_CHECK.
key_get_instantiation_authkey() also currently doesn't specify whether to
check the key state or not - but it probably should also set DO_STATE_CHECK.
Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: Chuck Lever <chuck.lever@oracle.com>
When a key description argument is imported into the kernel from userspace, as
happens in add_key(), request_key(), KEYCTL_JOIN_SESSION_KEYRING,
KEYCTL_SEARCH, the description is copied into a buffer up to PAGE_SIZE in size.
PAGE_SIZE, however, is a variable quantity, depending on the arch. Fix this at
4096 instead (ie. 4095 plus a NUL termination) and define a constant
(KEY_MAX_DESC_SIZE) to this end.
When reading the description back with KEYCTL_DESCRIBE, a PAGE_SIZE internal
buffer is allocated into which the information and description will be
rendered. This means that the description will get truncated if an extremely
long description it has to be crammed into the buffer with the stringified
information. There is no particular need to copy the description into the
buffer, so just copy it directly to userspace in a separate operation.
Reported-by: Christian Kastner <debian@kvr.at>
Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: Christian Kastner <debian@kvr.at>
integrity_kernel_read() duplicates the file read operations code
in vfs_read(). This patch refactors vfs_read() code creating a
helper function __vfs_read(). It is used by both vfs_read() and
integrity_kernel_read().
Signed-off-by: Dmitry Kasatkin <d.kasatkin@samsung.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
This patch provides CONFIG_IMA_APPRAISE_SIGNED_INIT kernel configuration
option to force IMA appraisal using signatures. This is useful, when EVM
key is not initialized yet and we want securely initialize integrity or
any other functionality.
It forces embedded policy to require signature. Signed initialization
script can initialize EVM key, update the IMA policy and change further
requirement of everything to be signed.
Changes in v3:
* kernel parameter fixed to configuration option in the patch description
Changes in v2:
* policy change of this patch separated from the key loading patch
Signed-off-by: Dmitry Kasatkin <d.kasatkin@samsung.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Keys can only be loaded once the rootfs is mounted. Initcalls
are not suitable for that. This patch defines a special hook
to load the x509 public keys onto the IMA keyring, before
attempting to access any file. The keys are required for
verifying the file's signature. The hook is called after the
root filesystem is mounted and before the kernel calls 'init'.
Changes in v3:
* added more explanation to the patch description (Mimi)
Changes in v2:
* Hook renamed as 'integrity_load_keys()' to handle both IMA and EVM
keys by integrity subsystem.
* Hook patch moved after defining loading functions
Signed-off-by: Dmitry Kasatkin <d.kasatkin@samsung.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Define configuration option to load X509 certificate into the
IMA trusted kernel keyring. It implements ima_load_x509() hook
to load X509 certificate into the .ima trusted kernel keyring
from the root filesystem.
Changes in v3:
* use ima_policy_flag in ima_get_action()
ima_load_x509 temporarily clears ima_policy_flag to disable
appraisal to load key. Use it to skip appraisal rules.
* Key directory path changed to /etc/keys (Mimi)
* Expand IMA_LOAD_X509 Kconfig help
Changes in v2:
* added '__init'
* use ima_policy_flag to disable appraisal to load keys
Signed-off-by: Dmitry Kasatkin <d.kasatkin@samsung.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Provide the function to load x509 certificates from the kernel into the
integrity kernel keyring.
Changes in v2:
* configuration option removed
* function declared as '__init'
Signed-off-by: Dmitry Kasatkin <d.kasatkin@samsung.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
This patch defines a new function called integrity_read_file()
to read file from the kernel into a buffer. Subsequent patches
will read a file containing the public keys and load them onto
the IMA keyring.
This patch moves and renames ima_kernel_read(), the non-security
checking version of kernel_read(), to integrity_kernel_read().
Changes in v3:
* Patch descriptions improved (Mimi)
* Add missing cast (kbuild test robot)
Changes in v2:
* configuration option removed
* function declared as '__init'
Signed-off-by: Dmitry Kasatkin <d.kasatkin@samsung.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
