For possibility to use xattr type for new signature formats,
pass full xattr to the signature verification function.
Signed-off-by: Dmitry Kasatkin <d.kasatkin@samsung.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Before modifying an EVM protected extended attribute or any other
metadata included in the HMAC calculation, the existing 'security.evm'
is verified. This patch adds calls to integrity_audit_msg() to audit
integrity metadata failures.
Reported-by: Sven Vermeulen <sven.vermeulen@siphos.be>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Pull security subsystem updates from James Morris:
"This is basically a maintenance update for the TPM driver and EVM/IMA"
Fix up conflicts in lib/digsig.c and security/integrity/ima/ima_main.c
* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security: (45 commits)
tpm/ibmvtpm: build only when IBM pseries is configured
ima: digital signature verification using asymmetric keys
ima: rename hash calculation functions
ima: use new crypto_shash API instead of old crypto_hash
ima: add policy support for file system uuid
evm: add file system uuid to EVM hmac
tpm_tis: check pnp_acpi_device return code
char/tpm/tpm_i2c_stm_st33: drop temporary variable for return value
char/tpm/tpm_i2c_stm_st33: remove dead assignment in tpm_st33_i2c_probe
char/tpm/tpm_i2c_stm_st33: Remove __devexit attribute
char/tpm/tpm_i2c_stm_st33: Don't use memcpy for one byte assignment
tpm_i2c_stm_st33: removed unused variables/code
TPM: Wait for TPM_ACCESS tpmRegValidSts to go high at startup
tpm: Fix cancellation of TPM commands (interrupt mode)
tpm: Fix cancellation of TPM commands (polling mode)
tpm: Store TPM vendor ID
TPM: Work around buggy TPMs that block during continue self test
tpm_i2c_stm_st33: fix oops when i2c client is unavailable
char/tpm: Use struct dev_pm_ops for power management
TPM: STMicroelectronics ST33 I2C BUILD STUFF
...
EVM uses the same key for all file systems to calculate the HMAC,
making it possible to paste inodes from one file system on to another
one, without EVM being able to detect it. To prevent such an attack,
it is necessary to make the EVM HMAC file system specific.
This patch uses the file system UUID, a file system unique identifier,
to bind the EVM HMAC to the file system. The value inode->i_sb->s_uuid
is used for the HMAC hash calculation, instead of using it for deriving
the file system specific key. Initializing the key for every inode HMAC
calculation is a bit more expensive operation than adding the uuid to
the HMAC hash.
Changing the HMAC calculation method or adding additional info to the
calculation, requires existing EVM labeled file systems to be relabeled.
This patch adds a Kconfig HMAC version option for backwards compatability.
Changelog v1:
- squash "hmac version setting"
Changelog v0:
- add missing Kconfig depends (Mimi)
Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@intel.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Pull security subsystem updates from James Morris:
"Highlights:
- Integrity: add local fs integrity verification to detect offline
attacks
- Integrity: add digital signature verification
- Simple stacking of Yama with other LSMs (per LSS discussions)
- IBM vTPM support on ppc64
- Add new driver for Infineon I2C TIS TPM
- Smack: add rule revocation for subject labels"
Fixed conflicts with the user namespace support in kernel/auditsc.c and
security/integrity/ima/ima_policy.c.
* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security: (39 commits)
Documentation: Update git repository URL for Smack userland tools
ima: change flags container data type
Smack: setprocattr memory leak fix
Smack: implement revoking all rules for a subject label
Smack: remove task_wait() hook.
ima: audit log hashes
ima: generic IMA action flag handling
ima: rename ima_must_appraise_or_measure
audit: export audit_log_task_info
tpm: fix tpm_acpi sparse warning on different address spaces
samples/seccomp: fix 31 bit build on s390
ima: digital signature verification support
ima: add support for different security.ima data types
ima: add ima_inode_setxattr/removexattr function and calls
ima: add inode_post_setattr call
ima: replace iint spinblock with rwlock/read_lock
ima: allocating iint improvements
ima: add appraise action keywords and default rules
ima: integrity appraisal extension
vfs: move ima_file_free before releasing the file
...
IMA currently maintains an integrity measurement list used to assert the
integrity of the running system to a third party. The IMA-appraisal
extension adds local integrity validation and enforcement of the
measurement against a "good" value stored as an extended attribute
'security.ima'. The initial methods for validating 'security.ima' are
hashed based, which provides file data integrity, and digital signature
based, which in addition to providing file data integrity, provides
authenticity.
This patch creates and maintains the 'security.ima' xattr, containing
the file data hash measurement. Protection of the xattr is provided by
EVM, if enabled and configured.
Based on policy, IMA calls evm_verifyxattr() to verify a file's metadata
integrity and, assuming success, compares the file's current hash value
with the one stored as an extended attribute in 'security.ima'.
Changelov v4:
- changed iint cache flags to hex values
Changelog v3:
- change appraisal default for filesystems without xattr support to fail
Changelog v2:
- fix audit msg 'res' value
- removed unused 'ima_appraise=' values
Changelog v1:
- removed unused iint mutex (Dmitry Kasatkin)
- setattr hook must not reset appraised (Dmitry Kasatkin)
- evm_verifyxattr() now differentiates between no 'security.evm' xattr
(INTEGRITY_NOLABEL) and no EVM 'protected' xattrs included in the
'security.evm' (INTEGRITY_NOXATTRS).
- replace hash_status with ima_status (Dmitry Kasatkin)
- re-initialize slab element ima_status on free (Dmitry Kasatkin)
- include 'security.ima' in EVM if CONFIG_IMA_APPRAISE, not CONFIG_IMA
- merged half "ima: ima_must_appraise_or_measure API change" (Dmitry Kasatkin)
- removed unnecessary error variable in process_measurement() (Dmitry Kasatkin)
- use ima_inode_post_setattr() stub function, if IMA_APPRAISE not configured
(moved ima_inode_post_setattr() to ima_appraise.c)
- make sure ima_collect_measurement() can read file
Changelog:
- add 'iint' to evm_verifyxattr() call (Dimitry Kasatkin)
- fix the race condition between chmod, which takes the i_mutex and then
iint->mutex, and ima_file_free() and process_measurement(), which take
the locks in the reverse order, by eliminating iint->mutex. (Dmitry Kasatkin)
- cleanup of ima_appraise_measurement() (Dmitry Kasatkin)
- changes as a result of the iint not allocated for all regular files, but
only for those measured/appraised.
- don't try to appraise new/empty files
- expanded ima_appraisal description in ima/Kconfig
- IMA appraise definitions required even if IMA_APPRAISE not enabled
- add return value to ima_must_appraise() stub
- unconditionally set status = INTEGRITY_PASS *after* testing status,
not before. (Found by Joe Perches)
Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@intel.com>
On multi-core systems, setting of the key before every caclculation,
causes invalid HMAC calculation for other tfm users, because internal
state (ipad, opad) can be invalid before set key call returns.
It needs to be set only once during initialization.
Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@intel.com>
Acked-by: Mimi Zohar <zohar@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
On multi-core systems, setting of the key before every caclculation,
causes invalid HMAC calculation for other tfm users, because internal
state (ipad, opad) can be invalid before set key call returns.
It needs to be set only once during initialization.
Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@intel.com>
Acked-by: Mimi Zohar <zohar@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
This patch adds support for digital signature verification to EVM.
With this feature file metadata can be protected using digital
signature instead of an HMAC. When building an image,
which has to be flashed to different devices, an HMAC cannot
be used to sign file metadata, because the HMAC key should be
different on every device.
Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@intel.com>
Acked-by: Mimi Zohar <zohar@us.ibm.com>
Before permitting 'security.evm' to be updated, 'security.evm' must
exist and be valid. In the case that there are no existing EVM protected
xattrs, it is safe for posix acls to update the mode bits.
To differentiate between no 'security.evm' xattr and no xattrs used to
calculate 'security.evm', this patch defines INTEGRITY_NOXATTR.
Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
The posix xattr acls are 'system' prefixed, which normally would not
affect security.evm. An interesting side affect of writing posix xattr
acls is their modifying of the i_mode, which is included in security.evm.
This patch updates security.evm when posix xattr acls are written.
Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
evm_protect_xattr unnecessarily validates the current security.evm
integrity, before updating non-evm protected extended attributes
and other file metadata. This patch limits validating the current
security.evm integrity to evm protected metadata.
Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
All tristates selected by EVM(boolean) are forced to be builtin, except
in the TCG_TPM(tristate) dependency case. Arnaud Lacombe summarizes the
Kconfig bug as, "So it would seem direct dependency state influence the
state of reverse dependencies.." For a detailed explanation, refer to
Arnaud Lacombe's posting http://lkml.org/lkml/2011/8/23/498.
With the "encrypted-keys: remove trusted-keys dependency" patch, EVM
can now be built without a dependency on TCG_TPM. The trusted-keys
dependency requires trusted-keys to either be builtin or not selected.
This dependency will prevent the boolean/tristate mismatch from
occuring.
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>,
Randy Dunlap <rdunlap@xenotimenet>
Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
Although the EVM encrypted-key should be encrypted/decrypted using a
trusted-key, a user-defined key could be used instead. When using a user-
defined key, a TCG_TPM dependency should not be required. Unfortunately,
the encrypted-key code needs to be refactored a bit in order to remove
this dependency.
This patch adds the TCG_TPM dependency.
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>,
Randy Dunlap <rdunlap@xenotimenet>
Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
evm_inode_init_security() should return 0, when EVM is not enabled.
(Returning an error is a remnant of evm_inode_post_init_security.)
Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
Select trusted and encrypted keys if EVM is selected, to ensure
the requisite symbols are available. Otherwise, these can be
selected as modules while EVM is static, leading to a kernel
build failure.
Signed-off-by: James Morris <jmorris@namei.org>
Permit changing of security.evm only when valid, unless in fixmode.
Reported-by: Roberto Sassu <roberto.sassu@polito.it>
Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
