Commit Graph

91 Commits

Author SHA1 Message Date
Wei Yongjun 3dd0f18c70 EVM: fix return value check in evm_write_xattrs()
In case of error, the function audit_log_start() returns NULL pointer
not ERR_PTR(). The IS_ERR() test in the return value check should be
replaced with NULL test.

Fixes: fa516b66a1 ("EVM: Allow runtime modification of the set of verified xattrs")
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Acked-by: Serge Hallyn <serge@hallyn.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2018-07-22 14:49:11 -04:00
Matthew Garrett 5feeb61183 evm: Allow non-SHA1 digital signatures
SHA1 is reasonable in HMAC constructs, but it's desirable to be able to
use stronger hashes in digital signatures. Modify the EVM crypto code so
the hash type is imported from the digital signature and passed down to
the hash calculation code, and return the digest size to higher layers
for validation.

Signed-off-by: Matthew Garrett <mjg59@google.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
2018-07-18 07:27:22 -04:00
Matthew Garrett e2861fa716 evm: Don't deadlock if a crypto algorithm is unavailable
When EVM attempts to appraise a file signed with a crypto algorithm the
kernel doesn't have support for, it will cause the kernel to trigger a
module load. If the EVM policy includes appraisal of kernel modules this
will in turn call back into EVM - since EVM is holding a lock until the
crypto initialisation is complete, this triggers a deadlock. Add a
CRYPTO_NOLOAD flag and skip module loading if it's set, and add that flag
in the EVM case in order to fail gracefully with an error message
instead of deadlocking.

Signed-off-by: Matthew Garrett <mjg59@google.com>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
2018-07-18 07:27:22 -04:00
Linus Torvalds 00d535a386 Merge branch 'next-integrity' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security
Pull integrity updates from James Morris:
 "From Mimi:

   - add run time support for specifying additional security xattrs
     included in the security.evm HMAC/signature

   - some code clean up and bug fixes"

* 'next-integrity' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security:
  EVM: unlock on error path in evm_read_xattrs()
  EVM: prevent array underflow in evm_write_xattrs()
  EVM: Fix null dereference on xattr when xattr fails to allocate
  EVM: fix memory leak of temporary buffer 'temp'
  IMA: use list_splice_tail_init_rcu() instead of its open coded variant
  ima: use match_string() helper
  ima: fix updating the ima_appraise flag
  ima: based on policy verify firmware signatures (pre-allocated buffer)
  ima: define a new policy condition based on the filesystem name
  EVM: Allow runtime modification of the set of verified xattrs
  EVM: turn evm_config_xattrnames into a list
  integrity: Add an integrity directory in securityfs
  ima: Remove unused variable ima_initialized
  ima: Unify logging
  ima: Reflect correct permissions for policy
2018-06-07 15:40:37 -07:00
Dan Carpenter b5c90a7526 EVM: unlock on error path in evm_read_xattrs()
We need to unlock before returning on this error path.

Fixes: fa516b66a1 ("EVM: Allow runtime modification of the set of verified xattrs")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
2018-06-01 06:03:08 -04:00
Dan Carpenter a41d80acfa EVM: prevent array underflow in evm_write_xattrs()
If the user sets xattr->name[0] to NUL then we would read one character
before the start of the array.  This bug seems harmless as far as I can
see but perhaps it would trigger a warning in KASAN.

Fixes: fa516b66a1 ("EVM: Allow runtime modification of the set of verified xattrs")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
2018-05-31 10:13:24 -04:00
Colin Ian King 72acd64df4 EVM: Fix null dereference on xattr when xattr fails to allocate
In the case where the allocation of xattr fails and xattr is NULL, the
error exit return path via label 'out' will dereference xattr when
kfree'ing xattr-name.  Fix this by only kfree'ing xattr->name and xattr
when xattr is non-null.

Detected by CoverityScan, CID#1469366 ("Dereference after null check")

Fixes: fa516b66a1 ("EVM: Allow runtime modification of the set of verified xattrs")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
2018-05-31 10:13:23 -04:00
Colin Ian King 825b8650dc EVM: fix memory leak of temporary buffer 'temp'
The allocation of 'temp' is not kfree'd and hence there is a memory
leak on each call of evm_read_xattrs.  Fix this by kfree'ing it
after copying data from it back to the user space buffer 'buf'.

Detected by CoverityScan, CID#1469386 ("Resource Leak")

Fixes: fa516b66a1 ("EVM: Allow runtime modification of the set of verified xattrs")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
2018-05-31 10:13:22 -04:00
Matthew Garrett fa516b66a1 EVM: Allow runtime modification of the set of verified xattrs
Sites may wish to provide additional metadata alongside files in order
to make more fine-grained security decisions[1]. The security of this is
enhanced if this metadata is protected, something that EVM makes
possible. However, the kernel cannot know about the set of extended
attributes that local admins may wish to protect, and hardcoding this
policy in the kernel makes it difficult to change over time and less
convenient for distributions to enable.

This patch adds a new /sys/kernel/security/integrity/evm/evm_xattrs node,
which can be read to obtain the current set of EVM-protected extended
attributes or written to in order to add new entries. Extending this list
will not change the validity of any existing signatures provided that the
file in question does not have any of the additional extended attributes -
missing xattrs are skipped when calculating the EVM hash.

[1] For instance, a package manager could install information about the
package uploader in an additional extended attribute. Local LSM policy
could then be associated with that extended attribute in order to
restrict the privileges available to packages from less trusted
uploaders.

Signed-off-by: Matthew Garrett <mjg59@google.com>
Reviewed-by: James Morris <james.morris@microsoft.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
2018-05-18 15:34:45 -04:00
Matthew Garrett 21af766314 EVM: turn evm_config_xattrnames into a list
Use a list of xattrs rather than an array - this makes it easier to
extend the list at runtime.

Signed-off-by: Matthew Garrett <mjg59@google.com>
Reviewed-by: James Morris <james.morris@microsoft.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
2018-05-18 15:34:36 -04:00
Matthew Garrett 0c343af806 integrity: Add an integrity directory in securityfs
We want to add additional evm control nodes, and it'd be preferable not
to clutter up the securityfs root directory any further. Create a new
integrity directory, move the ima directory into it, create an evm
directory for the evm attribute and add compatibility symlinks.

Signed-off-by: Matthew Garrett <mjg59@google.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
2018-05-17 08:03:07 -04:00
Seth Forshee a3a5c966a6 evm: Don't update hmacs in user ns mounts
The kernel should not calculate new hmacs for mounts done by
non-root users. Update evm_calc_hmac_or_hash() to refuse to
calculate new hmacs for mounts for non-init user namespaces.

Cc: linux-integrity@vger.kernel.org
Cc: linux-security-module@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: James Morris <james.l.morris@oracle.com>
Cc: Mimi Zohar <zohar@linux.vnet.ibm.com>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Signed-off-by: Seth Forshee <seth.forshee@canonical.com>
Signed-off-by: Dongsu Park <dongsu@kinvolk.io>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
2018-05-03 11:28:29 -05:00
Sascha Hauer 70946c4ac2 evm: check for remount ro in progress before writing
EVM might update the evm xattr while the VFS performs a remount to
readonly mode. This is not properly checked for, additionally check
the s_readonly_remount superblock flag before writing.

The bug can for example be observed with UBIFS. UBIFS checks the free
space on the device before and after a remount. With EVM enabled the
free space sometimes differs between both checks.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
2018-03-25 07:26:31 -04:00
Hernán Gonzalez 17d7b0af06 evm: Constify *integrity_status_msg[]
There is no gain from doing this except for some self-documenting.

Signed-off-by: Hernán Gonzalez <hernan@vanguardiasur.com.ar>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
2018-03-23 06:31:37 -04:00
Hernán Gonzalez 1a82cee3e6 evm: Move evm_hmac and evm_hash from evm_main.c to evm_crypto.c
These variables are not used where they are was defined.  There is no
point in declaring them there as extern.  Move and constify them, saving
2 bytes.

Function                                     old     new   delta
init_desc                                    273     271      -2
Total: Before=2112094, After=2112092, chg -0.00%

Signed-off-by: Hernán Gonzalez <hernan@vanguardiasur.com.ar>
Tested-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
2018-03-23 06:31:37 -04:00
Matthew Garrett 50b977481f EVM: Add support for portable signature format
The EVM signature includes the inode number and (optionally) the
filesystem UUID, making it impractical to ship EVM signatures in
packages. This patch adds a new portable format intended to allow
distributions to include EVM signatures. It is identical to the existing
format but hardcodes the inode and generation numbers to 0 and does not
include the filesystem UUID even if the kernel is configured to do so.

Removing the inode means that the metadata and signature from one file
could be copied to another file without invalidating it. This is avoided
by ensuring that an IMA xattr is present during EVM validation.

Portable signatures are intended to be immutable - ie, they will never
be transformed into HMACs.

Based on earlier work by Dmitry Kasatkin and Mikhail Kurinnoi.

Signed-off-by: Matthew Garrett <mjg59@google.com>
Cc: Dmitry Kasatkin <dmitry.kasatkin@huawei.com>
Cc: Mikhail Kurinnoi <viewizard@viewizard.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
2017-12-11 17:20:39 -05:00
Matthew Garrett ae1ba1676b EVM: Allow userland to permit modification of EVM-protected metadata
When EVM is enabled it forbids modification of metadata protected by
EVM unless there is already a valid EVM signature. If any modification
is made, the kernel will then generate a new EVM HMAC. However, this
does not map well on use cases which use only asymmetric EVM signatures,
as in this scenario the kernel is unable to generate new signatures.

This patch extends the /sys/kernel/security/evm interface to allow
userland to request that modification of these xattrs be permitted. This
is only permitted if no keys have already been loaded. In this
configuration, modifying the metadata will invalidate the EVM appraisal
on the file in question. This allows packaging systems to write out new
files, set the relevant extended attributes and then move them into
place.

There's also some refactoring of the use of evm_initialized in order to
avoid heading down codepaths that assume there's a key available.

Signed-off-by: Matthew Garrett <mjg59@google.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
2017-12-11 14:27:31 -05:00
Matthew Garrett 0485d066d8 EVM: Only complain about a missing HMAC key once
A system can validate EVM digital signatures without requiring an HMAC
key, but every EVM validation will generate a kernel error. Change this
so we only generate an error once.

Signed-off-by: Matthew Garrett <mjg59@google.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
2017-11-08 15:16:36 -05:00
Matthew Garrett f00d797507 EVM: Allow userspace to signal an RSA key has been loaded
EVM will only perform validation once a key has been loaded. This key
may either be a symmetric trusted key (for HMAC validation and creation)
or the public half of an asymmetric key (for digital signature
validation). The /sys/kernel/security/evm interface allows userland to
signal that a symmetric key has been loaded, but does not allow userland
to signal that an asymmetric public key has been loaded.

This patch extends the interface to permit userspace to pass a bitmask
of loaded key types. It also allows userspace to block loading of a
symmetric key in order to avoid a compromised system from being able to
load an additional key type later.

Signed-off-by: Matthew Garrett <mjg59@google.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
2017-11-08 15:16:36 -05:00
Matthew Garrett 096b854648 EVM: Include security.apparmor in EVM measurements
Apparmor will be gaining support for security.apparmor labels, and it
would be helpful to include these in EVM validation now so appropriate
signatures can be generated even before full support is merged.

Signed-off-by: Matthew Garrett <mjg59@google.com>
Acked-by: John Johansen <John.johansen@canonical.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
2017-11-08 15:16:36 -05:00
Christoph Hellwig 85787090a2 fs: switch ->s_uuid to uuid_t
For some file systems we still memcpy into it, but in various places this
already allows us to use the proper uuid helpers.  More to come..

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Acked-by: Mimi Zohar <zohar@linux.vnet.ibm.com> (Changes to IMA/EVM)
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
2017-06-05 16:59:12 +02:00
Ingo Molnar 50d34394ce sched/headers: Prepare to remove the <linux/magic.h> include from <linux/sched/task_stack.h>
Update files that depend on the magic.h inclusion.

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>
2017-03-02 08:42:40 +01:00
Linus Torvalds 412ac77a9d Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
Pull namespace updates from Eric Biederman:
 "After a lot of discussion and work we have finally reachanged a basic
  understanding of what is necessary to make unprivileged mounts safe in
  the presence of EVM and IMA xattrs which the last commit in this
  series reflects. While technically it is a revert the comments it adds
  are important for people not getting confused in the future. Clearing
  up that confusion allows us to seriously work on unprivileged mounts
  of fuse in the next development cycle.

  The rest of the fixes in this set are in the intersection of user
  namespaces, ptrace, and exec. I started with the first fix which
  started a feedback cycle of finding additional issues during review
  and fixing them. Culiminating in a fix for a bug that has been present
  since at least Linux v1.0.

  Potentially these fixes were candidates for being merged during the rc
  cycle, and are certainly backport candidates but enough little things
  turned up during review and testing that I decided they should be
  handled as part of the normal development process just to be certain
  there were not any great surprises when it came time to backport some
  of these fixes"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
  Revert "evm: Translate user/group ids relative to s_user_ns when computing HMAC"
  exec: Ensure mm->user_ns contains the execed files
  ptrace: Don't allow accessing an undumpable mm
  ptrace: Capture the ptracer's creds not PT_PTRACE_CAP
  mm: Add a user_ns owner to mm_struct and fix ptrace permission checks
2016-12-14 14:09:48 -08:00
Eric W. Biederman 19339c2516 Revert "evm: Translate user/group ids relative to s_user_ns when computing HMAC"
This reverts commit 0b3c9761d1.

Seth Forshee <seth.forshee@canonical.com> writes:
> All right, I think 0b3c9761d1 should be
> reverted then. EVM is a machine-local integrity mechanism, and so it
> makes sense that the signature would be based on the kernel's notion of
> the uid and not the filesystem's.

I added a commment explaining why the EVM hmac needs to be in the
kernel's notion of uid and gid, not the filesystems to prevent
remounting the filesystem and gaining unwaranted trust in files.

Acked-by: Seth Forshee <seth.forshee@canonical.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2016-12-02 20:58:41 -06:00
Seth Forshee b4bfec7f4a security/integrity: Harden against malformed xattrs
In general the handling of IMA/EVM xattrs is good, but I found
a few locations where either the xattr size or the value of the
type field in the xattr are not checked. Add a few simple checks
to these locations to prevent malformed or malicious xattrs from
causing problems.

Signed-off-by: Seth Forshee <seth.forshee@canonical.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
2016-11-13 22:50:11 -05:00
Andreas Gruenbacher 5d6c31910b xattr: Add __vfs_{get,set,remove}xattr helpers
Right now, various places in the kernel check for the existence of
getxattr, setxattr, and removexattr inode operations and directly call
those operations.  Switch to helper functions and test for the IOP_XATTR
flag instead.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Acked-by: James Morris <james.l.morris@oracle.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-10-07 20:10:44 -04:00
Seth Forshee 0b3c9761d1 evm: Translate user/group ids relative to s_user_ns when computing HMAC
The EVM HMAC should be calculated using the on disk user and
group ids, so the k[ug]ids in the inode must be translated
relative to the s_user_ns of the inode's super block.

Signed-off-by: Seth Forshee <seth.forshee@canonical.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
2016-07-05 15:13:10 -05:00
Al Viro ce23e64013 ->getxattr(): pass dentry and inode as separate arguments
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-04-11 00:48:00 -04:00
Al Viro fc64005c93 don't bother with ->d_inode->i_sb - it's always equal to ->d_sb
... and neither can ever be NULL

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-04-10 17:11:51 -04:00
Ryan Ware 613317bd21 EVM: Use crypto_memneq() for digest comparisons
This patch fixes vulnerability CVE-2016-2085.  The problem exists
because the vm_verify_hmac() function includes a use of memcmp().
Unfortunately, this allows timing side channel attacks; specifically
a MAC forgery complexity drop from 2^128 to 2^12.  This patch changes
the memcmp() to the cryptographically safe crypto_memneq().

Reported-by: Xiaofei Rex Guo <xiaofei.rex.guo@intel.com>
Signed-off-by: Ryan Ware <ware@linux.intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>
2016-02-12 18:36:47 +11:00
Arnd Bergmann 05d3884b1e evm: EVM_LOAD_X509 depends on EVM
The newly added EVM_LOAD_X509 code can be configured even if
CONFIG_EVM is disabled, but that causes a link error:

security/built-in.o: In function `integrity_load_keys':
digsig_asymmetric.c:(.init.text+0x400): undefined reference to `evm_load_x509'

This adds a Kconfig dependency to ensure it is only enabled when
CONFIG_EVM is set as well.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Fixes: 2ce523eb89 ("evm: load x509 certificate from the kernel")
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
2015-12-15 09:57:21 -05:00
Dmitry Kasatkin 523b74b16b evm: reset EVM status when file attributes change
The EVM verification status is cached in iint->evm_status and if it
was successful, never re-verified again when IMA passes the 'iint' to
evm_verifyxattr().

When file attributes or extended attributes change, we may wish to
re-verify EVM integrity as well.  For example, after setting a digital
signature we may need to re-verify the signature and update the
iint->flags that there is an EVM signature.

This patch enables that by resetting evm_status to INTEGRITY_UKNOWN
state.

Changes in v2:
* Flag setting moved to EVM layer

Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@huawei.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
2015-12-15 09:56:57 -05:00
Dmitry Kasatkin 7626676320 evm: provide a function to set the EVM key from the kernel
A crypto HW kernel module can possibly initialize the EVM key from the
kernel __init code to enable EVM before calling the 'init' process.
This patch provides a function evm_set_key() to set the EVM key
directly without using the KEY subsystem.

Changes in v4:
* kernel-doc style for evm_set_key

Changes in v3:
* error reporting moved to evm_set_key
* EVM_INIT_HMAC moved to evm_set_key
* added bitop to prevent key setting race

Changes in v2:
* use size_t for key size instead of signed int
* provide EVM_MAX_KEY_SIZE macro in <linux/evm.h>
* provide EVM_MIN_KEY_SIZE macro in <linux/evm.h>

Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@huawei.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
2015-12-15 08:53:36 -05:00
Dmitry Kasatkin 26ddabfe96 evm: enable EVM when X509 certificate is loaded
In order to enable EVM before starting the 'init' process,
evm_initialized needs to be non-zero.  Previously non-zero indicated
that the HMAC key was loaded.  When EVM loads the X509 before calling
'init', with this patch it is now possible to enable EVM to start
signature based verification.

This patch defines bits to enable EVM if a key of any type is loaded.

Changes in v3:
* print error message if key is not set

Changes in v2:
* EVM_STATE_KEY_SET replaced by EVM_INIT_HMAC
* EVM_STATE_X509_SET replaced by EVM_INIT_X509

Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@huawei.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
2015-12-15 08:50:48 -05:00
Dmitry Kasatkin 2ce523eb89 evm: load an x509 certificate from the kernel
This patch defines a configuration option and the evm_load_x509() hook
to load an X509 certificate onto the EVM trusted kernel keyring.

Changes in v4:
* Patch description updated

Changes in v3:
* Removed EVM_X509_PATH definition. CONFIG_EVM_X509_PATH is used
  directly.

Changes in v2:
* default key patch changed to /etc/keys

Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@huawei.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
2015-12-15 08:31:19 -05:00
Dmitry Kasatkin f4dc37785e integrity: define '.evm' as a builtin 'trusted' keyring
Require all keys added to the EVM keyring be signed by an
existing trusted key on the system trusted keyring.

This patch also switches IMA to use integrity_init_keyring().

Changes in v3:
* Added 'init_keyring' config based variable to skip initializing
  keyring instead of using  __integrity_init_keyring() wrapper.
* Added dependency back to CONFIG_IMA_TRUSTED_KEYRING

Changes in v2:
* Replace CONFIG_EVM_TRUSTED_KEYRING with IMA and EVM common
  CONFIG_INTEGRITY_TRUSTED_KEYRING configuration option
* Deprecate CONFIG_IMA_TRUSTED_KEYRING but keep it for config
  file compatibility. (Mimi Zohar)

Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@huawei.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
2015-11-23 14:30:02 -05:00
David Howells 146aa8b145 KEYS: Merge the type-specific data with the payload data
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: David 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
2015-10-21 15:18:36 +01:00
Dmitry Kasatkin 7c51bb00c4 evm: fix potential race when removing xattrs
EVM needs to be atomically updated when removing xattrs.
Otherwise concurrent EVM verification may fail in between.
This patch fixes by moving i_mutex unlocking after calling
EVM hook. fsnotify_xattr() is also now called while locked
the same way as it is done in __vfs_setxattr_noperm.

Changelog:
- remove unused 'inode' variable.

Signed-off-by: Dmitry Kasatkin <d.kasatkin@samsung.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
2015-05-21 13:28:47 -04:00
Mimi Zohar 5101a1850b evm: labeling pseudo filesystems exception
To prevent offline stripping of existing file xattrs and relabeling of
them at runtime, EVM allows only newly created files to be labeled.  As
pseudo filesystems are not persistent, stripping of xattrs is not a
concern.

Some LSMs defer file labeling on pseudo filesystems.  This patch
permits the labeling of existing files on pseudo files systems.

Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
2015-05-21 13:28:47 -04:00
David Howells c6f493d631 VFS: security/: d_backing_inode() annotations
most of the ->d_inode uses there refer to the same inode IO would
go to, i.e. d_backing_inode()

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-04-15 15:06:56 -04:00
Christoph Jaeger 6341e62b21 kconfig: use bool instead of boolean for type definition attributes
Support for keyword 'boolean' will be dropped later on.

No functional change.

Reference: http://lkml.kernel.org/r/cover.1418003065.git.cj@linux.com
Signed-off-by: Christoph Jaeger <cj@linux.com>
Signed-off-by: Michal Marek <mmarek@suse.cz>
2015-01-07 13:08:04 +01:00
Linus Torvalds 67e2c38838 Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security
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
  ...
2014-12-14 20:36:37 -08:00
Dmitry Kasatkin 3b1deef6b1 evm: check xattr value length and type in evm_inode_setxattr()
evm_inode_setxattr() can be called with no value. The function does not
check the length so that following command can be used to produce the
kernel oops: setfattr -n security.evm FOO. This patch fixes it.

Changes in v3:
* there is no reason to return different error codes for EVM_XATTR_HMAC
  and non EVM_XATTR_HMAC. Remove unnecessary test then.

Changes in v2:
* testing for validity of xattr type

[ 1106.396921] BUG: unable to handle kernel NULL pointer dereference at           (null)
[ 1106.398192] IP: [<ffffffff812af7b8>] evm_inode_setxattr+0x2a/0x48
[ 1106.399244] PGD 29048067 PUD 290d7067 PMD 0
[ 1106.399953] Oops: 0000 [#1] SMP
[ 1106.400020] Modules linked in: bridge stp llc evdev serio_raw i2c_piix4 button fuse
[ 1106.400020] CPU: 0 PID: 3635 Comm: setxattr Not tainted 3.16.0-kds+ #2936
[ 1106.400020] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[ 1106.400020] task: ffff8800291a0000 ti: ffff88002917c000 task.ti: ffff88002917c000
[ 1106.400020] RIP: 0010:[<ffffffff812af7b8>]  [<ffffffff812af7b8>] evm_inode_setxattr+0x2a/0x48
[ 1106.400020] RSP: 0018:ffff88002917fd50  EFLAGS: 00010246
[ 1106.400020] RAX: 0000000000000000 RBX: ffff88002917fdf8 RCX: 0000000000000000
[ 1106.400020] RDX: 0000000000000000 RSI: ffffffff818136d3 RDI: ffff88002917fdf8
[ 1106.400020] RBP: ffff88002917fd68 R08: 0000000000000000 R09: 00000000003ec1df
[ 1106.400020] R10: 0000000000000000 R11: 0000000000000000 R12: ffff8800438a0a00
[ 1106.400020] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
[ 1106.400020] FS:  00007f7dfa7d7740(0000) GS:ffff88005da00000(0000) knlGS:0000000000000000
[ 1106.400020] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 1106.400020] CR2: 0000000000000000 CR3: 000000003763e000 CR4: 00000000000006f0
[ 1106.400020] Stack:
[ 1106.400020]  ffff8800438a0a00 ffff88002917fdf8 0000000000000000 ffff88002917fd98
[ 1106.400020]  ffffffff812a1030 ffff8800438a0a00 ffff88002917fdf8 0000000000000000
[ 1106.400020]  0000000000000000 ffff88002917fde0 ffffffff8116d08a ffff88002917fdc8
[ 1106.400020] Call Trace:
[ 1106.400020]  [<ffffffff812a1030>] security_inode_setxattr+0x5d/0x6a
[ 1106.400020]  [<ffffffff8116d08a>] vfs_setxattr+0x6b/0x9f
[ 1106.400020]  [<ffffffff8116d1e0>] setxattr+0x122/0x16c
[ 1106.400020]  [<ffffffff811687e8>] ? mnt_want_write+0x21/0x45
[ 1106.400020]  [<ffffffff8114d011>] ? __sb_start_write+0x10f/0x143
[ 1106.400020]  [<ffffffff811687e8>] ? mnt_want_write+0x21/0x45
[ 1106.400020]  [<ffffffff811687c0>] ? __mnt_want_write+0x48/0x4f
[ 1106.400020]  [<ffffffff8116d3e6>] SyS_setxattr+0x6e/0xb0
[ 1106.400020]  [<ffffffff81529da9>] system_call_fastpath+0x16/0x1b
[ 1106.400020] Code: c3 0f 1f 44 00 00 55 48 89 e5 41 55 49 89 d5 41 54 49 89 fc 53 48 89 f3 48 c7 c6 d3 36 81 81 48 89 df e8 18 22 04 00 85 c0 75 07 <41> 80 7d 00 02 74 0d 48 89 de 4c 89 e7 e8 5a fe ff ff eb 03 83
[ 1106.400020] RIP  [<ffffffff812af7b8>] evm_inode_setxattr+0x2a/0x48
[ 1106.400020]  RSP <ffff88002917fd50>
[ 1106.400020] CR2: 0000000000000000
[ 1106.428061] ---[ end trace ae08331628ba3050 ]---

Reported-by: Jan Kara <jack@suse.cz>
Signed-off-by: Dmitry Kasatkin <d.kasatkin@samsung.com>
Cc: stable@vger.kernel.org
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
2014-10-28 10:06:31 -04:00
Dmitry Kasatkin c2baec7ffa evm: skip replacing EVM signature with HMAC on read-only filesystem
If filesystem is mounted read-only or file is immutable, updating
xattr will fail. This is a usual case during early boot until
filesystem is remount read-write. This patch verifies conditions
to skip unnecessary attempt to calculate HMAC and set xattr.

Changes in v2:
* indention changed according to Lindent (requested by Mimi)

Signed-off-by: Dmitry Kasatkin <d.kasatkin@samsung.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
2014-10-07 14:32:53 -04:00
Dmitry Kasatkin 7ef84e65ec integrity: base integrity subsystem kconfig options on integrity
The integrity subsystem has lots of options and takes more than
half of the security menu.  This patch consolidates the options
under "integrity", which are hidden if not enabled.  This change
does not affect existing configurations.  Re-configuration is not
needed.

Changes v4:
- no need to change "integrity subsystem" to menuconfig as
options are hidden, when not enabled. (Mimi)
- add INTEGRITY Kconfig help description

Changes v3:
- dependency to INTEGRITY removed when behind 'if INTEGRITY'

Changes v2:
- previous patch moved integrity out of the 'security' menu.
  This version keeps integrity as a security option (Mimi).

Signed-off-by: Dmitry Kasatkin <d.kasatkin@samsung.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
2014-09-09 10:28:56 -04:00
Dmitry Kasatkin 3dcbad52cf evm: properly handle INTEGRITY_NOXATTRS EVM status
Unless an LSM labels a file during d_instantiate(), newly created
files are not labeled with an initial security.evm xattr, until
the file closes.  EVM, before allowing a protected, security xattr
to be written, verifies the existing 'security.evm' value is good.
For newly created files without a security.evm label, this
verification prevents writing any protected, security xattrs,
until the file closes.

Following is the example when this happens:
fd = open("foo", O_CREAT | O_WRONLY, 0644);
setxattr("foo", "security.SMACK64", value, sizeof(value), 0);
close(fd);

While INTEGRITY_NOXATTRS status is handled in other places, such
as evm_inode_setattr(), it does not handle it in all cases in
evm_protect_xattr().  By limiting the use of INTEGRITY_NOXATTRS to
newly created files, we can now allow setting "protected" xattrs.

Changelog:
- limit the use of INTEGRITY_NOXATTRS to IMA identified new files

Signed-off-by: Dmitry Kasatkin <d.kasatkin@samsung.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Cc: <stable@vger.kernel.org>  3.14+
2014-09-09 10:26:10 -04:00
Dmitry Kasatkin 1f1009791b evm: prevent passing integrity check if xattr read fails
This patch fixes a bug, where evm_verify_hmac() returns INTEGRITY_PASS
if inode->i_op->getxattr() returns an error in evm_find_protected_xattrs.

Signed-off-by: Dmitry Kasatkin <d.kasatkin@samsung.com>
2014-09-08 17:36:10 -04:00
Dmitry Kasatkin e7d021e283 evm: fix checkpatch warnings
This patch fixes checkpatch 'return' warnings introduced with commit
9819cf2 "checkpatch: warn on unnecessary void function return statements".

Use scripts/checkpatch.pl --file security/integrity/evm/evm_main.c
to produce the warnings.

Signed-off-by: Dmitry Kasatkin <d.kasatkin@samsung.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
2014-09-02 17:03:37 -04:00
Mimi Zohar 2fb1c9a4f2 evm: prohibit userspace writing 'security.evm' HMAC value
Calculating the 'security.evm' HMAC value requires access to the
EVM encrypted key.  Only the kernel should have access to it.  This
patch prevents userspace tools(eg. setfattr, cp --preserve=xattr)
from setting/modifying the 'security.evm' HMAC value directly.

Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Cc: <stable@vger.kernel.org>
2014-06-12 17:58:07 -04:00
Dmitry Kasatkin 3e38df56e6 evm: provide option to protect additional SMACK xattrs
Newer versions of SMACK introduced following security xattrs:
SMACK64EXEC, SMACK64TRANSMUTE and SMACK64MMAP.

To protect these xattrs, this patch includes them in the HMAC
calculation.  However, for backwards compatibility with existing
labeled filesystems, including these xattrs needs to be
configurable.

Changelog:
- Add SMACK dependency on new option (Mimi)

Signed-off-by: Dmitry Kasatkin <d.kasatkin@samsung.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
2014-06-12 17:58:06 -04:00