What: security/ima/policy Date: May 2008 Contact: Mimi Zohar Description: The Trusted Computing Group(TCG) runtime Integrity Measurement Architecture(IMA) maintains a list of hash values of executables and other sensitive system files loaded into the run-time of this system. At runtime, the policy can be constrained based on LSM specific data. Policies are loaded into the securityfs file ima/policy by opening the file, writing the rules one at a time and then closing the file. The new policy takes effect after the file ima/policy is closed. rule format: action [condition ...] action: measure | dont_measure condition:= base | lsm base: [[func=] [mask=] [fsmagic=] [uid=]] lsm: [[subj_user=] [subj_role=] [subj_type=] [obj_user=] [obj_role=] [obj_type=]] base: func:= [BPRM_CHECK][FILE_MMAP][FILE_CHECK] mask:= [MAY_READ] [MAY_WRITE] [MAY_APPEND] [MAY_EXEC] fsmagic:= hex value uid:= decimal value lsm: are LSM specific default policy: # PROC_SUPER_MAGIC dont_measure fsmagic=0x9fa0 # SYSFS_MAGIC dont_measure fsmagic=0x62656572 # DEBUGFS_MAGIC dont_measure fsmagic=0x64626720 # TMPFS_MAGIC dont_measure fsmagic=0x01021994 # SECURITYFS_MAGIC dont_measure fsmagic=0x73636673 measure func=BPRM_CHECK measure func=FILE_MMAP mask=MAY_EXEC measure func=FILE_CHECK mask=MAY_READ uid=0 The default policy measures all executables in bprm_check, all files mmapped executable in file_mmap, and all files open for read by root in do_filp_open. Examples of LSM specific definitions: SELinux: # SELINUX_MAGIC dont_measure fsmagic=0xF97CFF8C dont_measure obj_type=var_log_t dont_measure obj_type=auditd_log_t measure subj_user=system_u func=FILE_CHECK mask=MAY_READ measure subj_role=system_r func=FILE_CHECK mask=MAY_READ Smack: measure subj_user=_ func=FILE_CHECK mask=MAY_READ