linux/Documentation/ABI/testing/ima_policy
Peter Moody e7c568e0fd ima: audit log hashes
This adds an 'audit' policy action which audit logs file measurements.

Changelog v6:
 - use new action flag handling (Dmitry Kasatkin).
 - removed whitespace (Mimi)

Changelog v5:
 - use audit_log_untrustedstring.

Changelog v4:
 - cleanup digest -> hash conversion.
 - use filename rather than d_path in ima_audit_measurement.

Changelog v3:
 - Use newly exported audit_log_task_info for logging pid/ppid/uid/etc.
 - Update the ima_policy ABI documentation.

Changelog v2:
 - Use 'audit' action rather than 'measure_and_audit' to permit
 auditing in the absence of measuring..

Changelog v1:
 - Initial posting.

Signed-off-by: Peter Moody <pmoody@google.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
2012-09-13 14:48:44 -04:00

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What: security/ima/policy
Date: May 2008
Contact: Mimi Zohar <zohar@us.ibm.com>
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.
IMA appraisal, if configured, uses these file measurements
for local measurement appraisal.
rule format: action [condition ...]
action: measure | dont_measure | appraise | dont_appraise | audit
condition:= base | lsm
base: [[func=] [mask=] [fsmagic=] [uid=] [fowner]]
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
fowner:=decimal value
lsm: are LSM specific
default policy:
# PROC_SUPER_MAGIC
dont_measure fsmagic=0x9fa0
dont_appraise fsmagic=0x9fa0
# SYSFS_MAGIC
dont_measure fsmagic=0x62656572
dont_appraise fsmagic=0x62656572
# DEBUGFS_MAGIC
dont_measure fsmagic=0x64626720
dont_appraise fsmagic=0x64626720
# TMPFS_MAGIC
dont_measure fsmagic=0x01021994
dont_appraise fsmagic=0x01021994
# RAMFS_MAGIC
dont_measure fsmagic=0x858458f6
dont_appraise fsmagic=0x858458f6
# SECURITYFS_MAGIC
dont_measure fsmagic=0x73636673
dont_appraise fsmagic=0x73636673
measure func=BPRM_CHECK
measure func=FILE_MMAP mask=MAY_EXEC
measure func=FILE_CHECK mask=MAY_READ uid=0
appraise fowner=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. The default appraisal
policy appraises all files owned by root.
Examples of LSM specific definitions:
SELinux:
# SELINUX_MAGIC
dont_measure fsmagic=0xf97cff8c
dont_appraise fsmagic=0xf97cff8c
dont_measure obj_type=var_log_t
dont_appraise obj_type=var_log_t
dont_measure obj_type=auditd_log_t
dont_appraise 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