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. New hooks: ima_inode_setxattr(), ima_inode_removexattr(), ima_inode_post_setattr(), and ima_defer_fput() IMA-appraisal extends the measurement policy ABI with two new keywords: appraise/dont_appraise and adds a new boot parameter 'ima_appraise_tcb' to appraise all files owned by root. Like the ima_tcb measurement policy, the ima_appraise_tcb policy does not appraise pseudo filesystem files (eg. debugfs, tmpfs, securityfs, selinuxfs or ramfs.) Additional rules can be added to the default IMA measurement/appraisal policy, which take advantage of the SELinux labels, for a more fine grained policy. Locking changes: The ima-appraisal extension maintains the file integrity measurement as an extended attribute 'security.ima'. ima_file_free(), called on __fput(), updates 'security.ima' to reflect any changes made to the file. In fix mode, process_measurement() writes 'security.ima' to reflect the current file hash. Writing extended attributes and other file metadata (eg. chmod), requires taking the i_mutex. Both ima_file_free() and process_measurement() took the iint->mutex and then the i_mutex, while chmod() took the locks in reverse order. To resolve the potential lock inversion deadlock, the redundant iint->mutex was eliminated. Writing 'security.ima' from __fput() caused an mmap_sem/i_mutex lockdep, when an mmapped file was closed before it was munmapped. To resolve this lockdep, ima_defer_fput() defers the __fput, by incrementing the f_count and creating/adding it to the workqueue. Prereqs: vfs: fix IMA lockdep circular locking dependency vfs: iversion truncate bug fix Changelog v3: - defined the boot command line parameter 'ima_appraise_tcb' to permit measuring without appraising, and appraising without measuring. - use slab mempool to defer __fput() work - change appraisal default for filesystems without xattr support to fail Changelog v2: - Split the "ima: allocating iint improvements" patch, making the spinlock to rwlock/read_lock change into a separate patch. - Removed the "vfs: Correctly set the dir i_mutex lockdep class" dependency. - New: "ima: delay calling __fput()" - Minor changes listed in individual patch descriptions Changelog v1: - Initial posting of the IMA-appraisal patches, separately from EVM. Mimi Dmitry Kasatkin (3): ima: free securityfs violations file ima: allocating iint improvements ima: digital signature verification support Mimi Zohar (9): vfs: extend vfs_removexattr locking vfs: move ima_file_free before releasing the file ima: integrity appraisal extension ima: add appraise action keywords and default rules ima: replace iint spinlock with rwlock/read_lock ima: add inode_post_setattr call ima: add ima_inode_setxattr/removexattr function and calls ima: defer calling __fput() ima: add support for different security.ima data types Documentation/ABI/testing/ima_policy | 25 ++- Documentation/kernel-parameters.txt | 8 + fs/attr.c | 2 + fs/file_table.c | 2 +- fs/xattr.c | 6 +- include/linux/ima.h | 32 +++ include/linux/integrity.h | 7 +- include/linux/xattr.h | 3 + mm/mmap.c | 1 + security/integrity/evm/evm_main.c | 3 + security/integrity/iint.c | 64 +++---- security/integrity/ima/Kconfig | 15 ++ security/integrity/ima/Makefile | 2 + security/integrity/ima/ima.h | 37 ++++- security/integrity/ima/ima_api.c | 56 ++++-- security/integrity/ima/ima_appraise.c | 347 +++++++++++++++++++++++++++++++++ security/integrity/ima/ima_crypto.c | 8 +- security/integrity/ima/ima_fs.c | 1 + security/integrity/ima/ima_main.c | 89 ++++++--- security/integrity/ima/ima_policy.c | 181 +++++++++++++----- security/integrity/integrity.h | 11 +- security/security.c | 6 + 22 files changed, 757 insertions(+), 149 deletions(-) create mode 100644 security/integrity/ima/ima_appraise.c -- 1.7.6.5 -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
