diff options
Diffstat (limited to 'Documentation/ABI/testing/ima_policy')
| -rw-r--r-- | Documentation/ABI/testing/ima_policy | 115 |
1 files changed, 95 insertions, 20 deletions
diff --git a/Documentation/ABI/testing/ima_policy b/Documentation/ABI/testing/ima_policy index 29aaedf33246..c2385183826c 100644 --- a/Documentation/ABI/testing/ima_policy +++ b/Documentation/ABI/testing/ima_policy @@ -1,4 +1,4 @@ -What: security/ima/policy +What: /sys/kernel/security/*/ima/policy Date: May 2008 Contact: Mimi Zohar <zohar@us.ibm.com> Description: @@ -15,38 +15,69 @@ Description: IMA appraisal, if configured, uses these file measurements for local measurement appraisal. - rule format: action [condition ...] + :: - action: measure | dont_measure | appraise | dont_appraise | - audit | hash | dont_hash - condition:= base | lsm [option] - base: [[func=] [mask=] [fsmagic=] [fsuuid=] [uid=] - [euid=] [fowner=] [fsname=]] + rule format: action [condition ...] + + action: measure | dont_measure | appraise | dont_appraise | + audit | hash | dont_hash + condition:= base | lsm [option] + base: [[func=] [mask=] [fsmagic=] [fsuuid=] [fsname=] + [uid=] [euid=] [gid=] [egid=] + [fowner=] [fgroup=]] lsm: [[subj_user=] [subj_role=] [subj_type=] [obj_user=] [obj_role=] [obj_type=]] - option: [[appraise_type=]] [template=] [permit_directio] - [appraise_flag=] - base: func:= [BPRM_CHECK][MMAP_CHECK][CREDS_CHECK][FILE_CHECK][MODULE_CHECK] + option: [digest_type=] [template=] [permit_directio] + [appraise_type=] [appraise_flag=] + [appraise_algos=] [keyrings=] + base: + func:= [BPRM_CHECK][MMAP_CHECK][CREDS_CHECK][FILE_CHECK][MODULE_CHECK] [FIRMWARE_CHECK] [KEXEC_KERNEL_CHECK] [KEXEC_INITRAMFS_CHECK] - [KEXEC_CMDLINE] + [KEXEC_CMDLINE] [KEY_CHECK] [CRITICAL_DATA] + [SETXATTR_CHECK][MMAP_CHECK_REQPROT] mask:= [[^]MAY_READ] [[^]MAY_WRITE] [[^]MAY_APPEND] [[^]MAY_EXEC] fsmagic:= hex value fsuuid:= file system UUID (e.g 8bcbe394-4f13-4144-be8e-5aa9ea2ce2f6) uid:= decimal value euid:= decimal value + gid:= decimal value + egid:= decimal value fowner:= decimal value - lsm: are LSM specific - option: appraise_type:= [imasig] [imasig|modsig] - appraise_flag:= [check_blacklist] - Currently, blacklist check is only for files signed with appended - signature. + fgroup:= decimal value + lsm: are LSM specific + option: + appraise_type:= [imasig] | [imasig|modsig] | [sigv3] + where 'imasig' is the original or the signature + format v2. + where 'modsig' is an appended signature, + where 'sigv3' is the signature format v3. (Currently + limited to fsverity digest based signatures + stored in security.ima xattr. Requires + specifying "digest_type=verity" first.) + + appraise_flag:= [check_blacklist] (deprecated) + Setting the check_blacklist flag is no longer necessary. + All appraisal functions set it by default. + digest_type:= verity + Require fs-verity's file digest instead of the + regular IMA file hash. + keyrings:= list of keyrings + (eg, .builtin_trusted_keys|.ima). Only valid + when action is "measure" and func is KEY_CHECK. template:= name of a defined IMA template type (eg, ima-ng). Only valid when action is "measure". pcr:= decimal value + label:= [selinux]|[kernel_info]|[data_label] + data_label:= a unique string used for grouping and limiting critical data. + For example, "selinux" to measure critical data for SELinux. + appraise_algos:= comma-separated list of hash algorithms + For example, "sha256,sha512" to only accept to appraise + files where the security.ima xattr was hashed with one + of these two algorithms. - default policy: + default policy: # PROC_SUPER_MAGIC dont_measure fsmagic=0x9fa0 dont_appraise fsmagic=0x9fa0 @@ -94,7 +125,8 @@ Description: Examples of LSM specific definitions: - SELinux: + SELinux:: + dont_measure obj_type=var_log_t dont_appraise obj_type=var_log_t dont_measure obj_type=auditd_log_t @@ -102,10 +134,11 @@ Description: measure subj_user=system_u func=FILE_CHECK mask=MAY_READ measure subj_role=system_r func=FILE_CHECK mask=MAY_READ - Smack: + Smack:: + measure subj_user=_ func=FILE_CHECK mask=MAY_READ - Example of measure rules using alternate PCRs: + Example of measure rules using alternate PCRs:: measure func=KEXEC_KERNEL_CHECK pcr=4 measure func=KEXEC_INITRAMFS_CHECK pcr=5 @@ -113,3 +146,45 @@ Description: Example of appraise rule allowing modsig appended signatures: appraise func=KEXEC_KERNEL_CHECK appraise_type=imasig|modsig + + Example of measure rule using KEY_CHECK to measure all keys: + + measure func=KEY_CHECK + + Example of measure rule using KEY_CHECK to only measure + keys added to .builtin_trusted_keys or .ima keyring: + + measure func=KEY_CHECK keyrings=.builtin_trusted_keys|.ima + + Example of the special SETXATTR_CHECK appraise rule, that + restricts the hash algorithms allowed when writing to the + security.ima xattr of a file: + + appraise func=SETXATTR_CHECK appraise_algos=sha256,sha384,sha512 + + Example of a 'measure' rule requiring fs-verity's digests + with indication of type of digest in the measurement list. + + measure func=FILE_CHECK digest_type=verity \ + template=ima-ngv2 + + Example of 'measure' and 'appraise' rules requiring fs-verity + signatures (format version 3) stored in security.ima xattr. + + The 'measure' rule specifies the 'ima-sigv3' template option, + which includes the indication of type of digest and the file + signature in the measurement list. + + measure func=BPRM_CHECK digest_type=verity \ + template=ima-sigv3 + + + The 'appraise' rule specifies the type and signature format + version (sigv3) required. + + appraise func=BPRM_CHECK digest_type=verity \ + appraise_type=sigv3 + + All of these policy rules could, for example, be constrained + either based on a filesystem's UUID (fsuuid) or based on LSM + labels. |