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