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>
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>
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>
Using HMAC version limits the posibility to arbitrarily add new
attributes such as SMACK64EXEC to the hmac calculation.
This patch replaces hmac version with attribute mask.
Desired attributes can be enabled with configuration parameter.
It allows to build kernels which works with previously labeled
filesystems.
Currently supported attribute is 'fsuuid' which is equivalent of
the former version 2.
Signed-off-by: Dmitry Kasatkin <d.kasatkin@samsung.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Pull vfs updates from Al Viro:
"The first vfs pile, with deep apologies for being very late in this
window.
Assorted cleanups and fixes, plus a large preparatory part of iov_iter
work. There's a lot more of that, but it'll probably go into the next
merge window - it *does* shape up nicely, removes a lot of
boilerplate, gets rid of locking inconsistencie between aio_write and
splice_write and I hope to get Kent's direct-io rewrite merged into
the same queue, but some of the stuff after this point is having
(mostly trivial) conflicts with the things already merged into
mainline and with some I want more testing.
This one passes LTP and xfstests without regressions, in addition to
usual beating. BTW, readahead02 in ltp syscalls testsuite has started
giving failures since "mm/readahead.c: fix readahead failure for
memoryless NUMA nodes and limit readahead pages" - might be a false
positive, might be a real regression..."
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (63 commits)
missing bits of "splice: fix racy pipe->buffers uses"
cifs: fix the race in cifs_writev()
ceph_sync_{,direct_}write: fix an oops on ceph_osdc_new_request() failure
kill generic_file_buffered_write()
ocfs2_file_aio_write(): switch to generic_perform_write()
ceph_aio_write(): switch to generic_perform_write()
xfs_file_buffered_aio_write(): switch to generic_perform_write()
export generic_perform_write(), start getting rid of generic_file_buffer_write()
generic_file_direct_write(): get rid of ppos argument
btrfs_file_aio_write(): get rid of ppos
kill the 5th argument of generic_file_buffered_write()
kill the 4th argument of __generic_file_aio_write()
lustre: don't open-code kernel_recvmsg()
ocfs2: don't open-code kernel_recvmsg()
drbd: don't open-code kernel_recvmsg()
constify blk_rq_map_user_iov() and friends
lustre: switch to kernel_sendmsg()
ocfs2: don't open-code kernel_sendmsg()
take iov_iter stuff to mm/iov_iter.c
process_vm_access: tidy up a bit
...
Between checkpatch changes (eg. sizeof) and inconsistencies between
Lindent and checkpatch, unfixed checkpatch errors make it difficult
to see new errors. This patch fixes them. Some lines with over 80 chars
remained unchanged to improve code readability.
The "extern" keyword is removed from internal evm.h to make it consistent
with internal ima.h.
Signed-off-by: Dmitry Kasatkin <d.kasatkin@samsung.com>
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>
There is a small chance of racing during tfm allocation.
This patch fixes it.
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>
There is a small chance of racing during tfm allocation.
This patch fixes it.
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>
Using shash is more efficient, because the algorithm is allocated only
once. Only the descriptor to store the hash state needs to be allocated
for every operation.
Changelog v6:
- check for crypto_shash_setkey failure
Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@nokia.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Initialize 'security.evm' for new files.
Changelog v7:
- renamed evm_inode_post_init_security to evm_inode_init_security
- moved struct xattr definition to earlier patch
- allocate xattr name
Changelog v6:
- Use 'struct evm_ima_xattr_data'
Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
EVM protects a file's security extended attributes(xattrs) against integrity
attacks. The current patchset maintains an HMAC-sha1 value across the security
xattrs, storing the value as the extended attribute 'security.evm'. We
anticipate other methods for protecting the security extended attributes.
This patch reserves the first byte of 'security.evm' as a place holder for
the type of method.
Changelog v6:
- move evm_ima_xattr_type definition to security/integrity/integrity.h
- defined a structure for the EVM xattr called evm_ima_xattr_data
(based on Serge Hallyn's suggestion)
- removed unnecessary memset
Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@nokia.com>
Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
EVM protects a file's security extended attributes(xattrs) against integrity
attacks. This patchset provides the framework and an initial method. The
initial method maintains an HMAC-sha1 value across the security extended
attributes, storing the HMAC value as the extended attribute 'security.evm'.
Other methods of validating the integrity of a file's metadata will be posted
separately (eg. EVM-digital-signatures).
While this patchset does authenticate the security xattrs, and
cryptographically binds them to the inode, coming extensions will bind other
directory and inode metadata for more complete protection. To help simplify
the review and upstreaming process, each extension will be posted separately
(eg. IMA-appraisal, IMA-appraisal-directory). For a general overview of the
proposed Linux integrity subsystem, refer to Dave Safford's whitepaper:
http://downloads.sf.net/project/linux-ima/linux-ima/Integrity_overview.pdf.
EVM depends on the Kernel Key Retention System to provide it with a
trusted/encrypted key for the HMAC-sha1 operation. The key is loaded onto the
root's keyring using keyctl. Until EVM receives notification that the key has
been successfully loaded onto the keyring (echo 1 > <securityfs>/evm), EVM can
not create or validate the 'security.evm' xattr, but returns INTEGRITY_UNKNOWN.
Loading the key and signaling EVM should be done as early as possible. Normally
this is done in the initramfs, which has already been measured as part of the
trusted boot. For more information on creating and loading existing
trusted/encrypted keys, refer to Documentation/keys-trusted-encrypted.txt. A
sample dracut patch, which loads the trusted/encrypted key and enables EVM, is
available from http://linux-ima.sourceforge.net/#EVM.
Based on the LSMs enabled, the set of EVM protected security xattrs is defined
at compile. EVM adds the following three calls to the existing security hooks:
evm_inode_setxattr(), evm_inode_post_setxattr(), and evm_inode_removexattr. To
initialize and update the 'security.evm' extended attribute, EVM defines three
calls: evm_inode_post_init(), evm_inode_post_setattr() and
evm_inode_post_removexattr() hooks. To verify the integrity of a security
xattr, EVM exports evm_verifyxattr().
Changelog v7:
- Fixed URL in EVM ABI documentation
Changelog v6: (based on Serge Hallyn's review)
- fix URL in patch description
- remove evm_hmac_size definition
- use SHA1_DIGEST_SIZE (removed both MAX_DIGEST_SIZE and evm_hmac_size)
- moved linux include before other includes
- test for crypto_hash_setkey failure
- fail earlier for invalid key
- clear entire encrypted key, even on failure
- check xattr name length before comparing xattr names
Changelog:
- locking based on i_mutex, remove evm_mutex
- using trusted/encrypted keys for storing the EVM key used in the HMAC-sha1
operation.
- replaced crypto hash with shash (Dmitry Kasatkin)
- support for additional methods of verifying the security xattrs
(Dmitry Kasatkin)
- iint not allocated for all regular files, but only for those appraised
- Use cap_sys_admin in lieu of cap_mac_admin
- Use __vfs_setxattr_noperm(), without permission checks, from EVM
Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Dmitry Kasatkin