linux/Documentation/ABI/testing/ima_policy

99 lines
3.2 KiB
Plaintext
Raw Normal View History

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: add appraise action keywords and default rules Unlike the IMA measurement policy, the appraise policy can not be dependent on runtime process information, such as the task uid, as the 'security.ima' xattr is written on file close and must be updated each time the file changes, regardless of the current task uid. This patch extends the policy language with 'fowner', defines an appraise policy, which appraises all files owned by root, and defines 'ima_appraise_tcb', a new boot command line option, to enable the appraise policy. Changelog v3: - separate the measure from the appraise rules in order to support measuring without appraising and appraising without measuring. - change appraisal default for filesystems without xattr support to fail - update default appraise policy for cgroups Changelog v1: - don't appraise RAMFS (Dmitry Kasatkin) - merged rest of "ima: ima_must_appraise_or_measure API change" commit (Dmtiry Kasatkin) ima_must_appraise_or_measure() called ima_match_policy twice, which searched the policy for a matching rule. Once for a matching measurement rule and subsequently for an appraisal rule. Searching the policy twice is unnecessary overhead, which could be noticeable with a large policy. The new version of ima_must_appraise_or_measure() does everything in a single iteration using a new version of ima_match_policy(). It returns IMA_MEASURE, IMA_APPRAISE mask. With the use of action mask only one efficient matching function is enough. Removed other specific versions of matching functions. Changelog: - change 'owner' to 'fowner' to conform to the new LSM conditions posted by Roberto Sassu. - fix calls to ima_log_string() Signed-off-by: Mimi Zohar <zohar@us.ibm.com> Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@intel.com>
2011-03-10 06:25:48 +03:00
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 [option]
base: [[func=] [mask=] [fsmagic=] [fsuuid=] [uid=]
[euid=] [fowner=]]
lsm: [[subj_user=] [subj_role=] [subj_type=]
[obj_user=] [obj_role=] [obj_type=]]
option: [[appraise_type=]] [permit_directio]
base: func:= [BPRM_CHECK][MMAP_CHECK][FILE_CHECK][MODULE_CHECK]
[FIRMWARE_CHECK]
ima: support for kexec image and initramfs Add IMA policy support for measuring/appraising the kexec image and initramfs. Two new IMA policy identifiers KEXEC_KERNEL_CHECK and KEXEC_INITRAMFS_CHECK are defined. Example policy rules: measure func=KEXEC_KERNEL_CHECK appraise func=KEXEC_KERNEL_CHECK appraise_type=imasig measure func=KEXEC_INITRAMFS_CHECK appraise func=KEXEC_INITRAMFS_CHECK appraise_type=imasig Moving the enumeration to the vfs layer simplified the patches, allowing the IMA changes, for the most part, to be separated from the other changes. Unfortunately, passing either a kernel_read_file_id or a ima_hooks enumeration within IMA is messy. Option 1: duplicate kernel_read_file enumeration in ima_hooks enum kernel_read_file_id { ... READING_KEXEC_IMAGE, READING_KEXEC_INITRAMFS, READING_MAX_ID enum ima_hooks { ... KEXEC_KERNEL_CHECK KEXEC_INITRAMFS_CHECK Option 2: define ima_hooks as extension of kernel_read_file eg: enum ima_hooks { FILE_CHECK = READING_MAX_ID, MMAP_CHECK, In order to pass both kernel_read_file_id and ima_hooks values, we would need to specify a struct containing a union. struct caller_id { union { enum ima_hooks func_id; enum kernel_read_file_id read_id; }; }; Option 3: incorportate the ima_hooks enumeration into kernel_read_file_id, perhaps changing the enumeration name. For now, duplicate the new READING_KEXEC_IMAGE/INITRAMFS in the ima_hooks. Changelog v4: - replaced switch statement with a kernel_read_file_id to an ima_hooks id mapping array - Dmitry - renamed ima_hook tokens KEXEC_CHECK and INITRAMFS_CHECK to KEXEC_KERNEL_CHECK and KEXEC_INITRAMFS_CHECK respectively - Dave Young Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com> Acked-by: Petko Manolov <petkan@mip-labs.com> Acked-by: Dmitry Kasatkin <dmitry.kasatkin@huawei.com> Cc: Dave Young <dyoung@redhat.com>
2016-01-15 04:59:14 +03:00
[KEXEC_KERNEL_CHECK] [KEXEC_INITRAMFS_CHECK]
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
ima: add appraise action keywords and default rules Unlike the IMA measurement policy, the appraise policy can not be dependent on runtime process information, such as the task uid, as the 'security.ima' xattr is written on file close and must be updated each time the file changes, regardless of the current task uid. This patch extends the policy language with 'fowner', defines an appraise policy, which appraises all files owned by root, and defines 'ima_appraise_tcb', a new boot command line option, to enable the appraise policy. Changelog v3: - separate the measure from the appraise rules in order to support measuring without appraising and appraising without measuring. - change appraisal default for filesystems without xattr support to fail - update default appraise policy for cgroups Changelog v1: - don't appraise RAMFS (Dmitry Kasatkin) - merged rest of "ima: ima_must_appraise_or_measure API change" commit (Dmtiry Kasatkin) ima_must_appraise_or_measure() called ima_match_policy twice, which searched the policy for a matching rule. Once for a matching measurement rule and subsequently for an appraisal rule. Searching the policy twice is unnecessary overhead, which could be noticeable with a large policy. The new version of ima_must_appraise_or_measure() does everything in a single iteration using a new version of ima_match_policy(). It returns IMA_MEASURE, IMA_APPRAISE mask. With the use of action mask only one efficient matching function is enough. Removed other specific versions of matching functions. Changelog: - change 'owner' to 'fowner' to conform to the new LSM conditions posted by Roberto Sassu. - fix calls to ima_log_string() Signed-off-by: Mimi Zohar <zohar@us.ibm.com> Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@intel.com>
2011-03-10 06:25:48 +03:00
fowner:=decimal value
lsm: are LSM specific
option: appraise_type:= [imasig]
default policy:
# PROC_SUPER_MAGIC
dont_measure fsmagic=0x9fa0
ima: add appraise action keywords and default rules Unlike the IMA measurement policy, the appraise policy can not be dependent on runtime process information, such as the task uid, as the 'security.ima' xattr is written on file close and must be updated each time the file changes, regardless of the current task uid. This patch extends the policy language with 'fowner', defines an appraise policy, which appraises all files owned by root, and defines 'ima_appraise_tcb', a new boot command line option, to enable the appraise policy. Changelog v3: - separate the measure from the appraise rules in order to support measuring without appraising and appraising without measuring. - change appraisal default for filesystems without xattr support to fail - update default appraise policy for cgroups Changelog v1: - don't appraise RAMFS (Dmitry Kasatkin) - merged rest of "ima: ima_must_appraise_or_measure API change" commit (Dmtiry Kasatkin) ima_must_appraise_or_measure() called ima_match_policy twice, which searched the policy for a matching rule. Once for a matching measurement rule and subsequently for an appraisal rule. Searching the policy twice is unnecessary overhead, which could be noticeable with a large policy. The new version of ima_must_appraise_or_measure() does everything in a single iteration using a new version of ima_match_policy(). It returns IMA_MEASURE, IMA_APPRAISE mask. With the use of action mask only one efficient matching function is enough. Removed other specific versions of matching functions. Changelog: - change 'owner' to 'fowner' to conform to the new LSM conditions posted by Roberto Sassu. - fix calls to ima_log_string() Signed-off-by: Mimi Zohar <zohar@us.ibm.com> Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@intel.com>
2011-03-10 06:25:48 +03:00
dont_appraise fsmagic=0x9fa0
# SYSFS_MAGIC
dont_measure fsmagic=0x62656572
ima: add appraise action keywords and default rules Unlike the IMA measurement policy, the appraise policy can not be dependent on runtime process information, such as the task uid, as the 'security.ima' xattr is written on file close and must be updated each time the file changes, regardless of the current task uid. This patch extends the policy language with 'fowner', defines an appraise policy, which appraises all files owned by root, and defines 'ima_appraise_tcb', a new boot command line option, to enable the appraise policy. Changelog v3: - separate the measure from the appraise rules in order to support measuring without appraising and appraising without measuring. - change appraisal default for filesystems without xattr support to fail - update default appraise policy for cgroups Changelog v1: - don't appraise RAMFS (Dmitry Kasatkin) - merged rest of "ima: ima_must_appraise_or_measure API change" commit (Dmtiry Kasatkin) ima_must_appraise_or_measure() called ima_match_policy twice, which searched the policy for a matching rule. Once for a matching measurement rule and subsequently for an appraisal rule. Searching the policy twice is unnecessary overhead, which could be noticeable with a large policy. The new version of ima_must_appraise_or_measure() does everything in a single iteration using a new version of ima_match_policy(). It returns IMA_MEASURE, IMA_APPRAISE mask. With the use of action mask only one efficient matching function is enough. Removed other specific versions of matching functions. Changelog: - change 'owner' to 'fowner' to conform to the new LSM conditions posted by Roberto Sassu. - fix calls to ima_log_string() Signed-off-by: Mimi Zohar <zohar@us.ibm.com> Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@intel.com>
2011-03-10 06:25:48 +03:00
dont_appraise fsmagic=0x62656572
# DEBUGFS_MAGIC
dont_measure fsmagic=0x64626720
ima: add appraise action keywords and default rules Unlike the IMA measurement policy, the appraise policy can not be dependent on runtime process information, such as the task uid, as the 'security.ima' xattr is written on file close and must be updated each time the file changes, regardless of the current task uid. This patch extends the policy language with 'fowner', defines an appraise policy, which appraises all files owned by root, and defines 'ima_appraise_tcb', a new boot command line option, to enable the appraise policy. Changelog v3: - separate the measure from the appraise rules in order to support measuring without appraising and appraising without measuring. - change appraisal default for filesystems without xattr support to fail - update default appraise policy for cgroups Changelog v1: - don't appraise RAMFS (Dmitry Kasatkin) - merged rest of "ima: ima_must_appraise_or_measure API change" commit (Dmtiry Kasatkin) ima_must_appraise_or_measure() called ima_match_policy twice, which searched the policy for a matching rule. Once for a matching measurement rule and subsequently for an appraisal rule. Searching the policy twice is unnecessary overhead, which could be noticeable with a large policy. The new version of ima_must_appraise_or_measure() does everything in a single iteration using a new version of ima_match_policy(). It returns IMA_MEASURE, IMA_APPRAISE mask. With the use of action mask only one efficient matching function is enough. Removed other specific versions of matching functions. Changelog: - change 'owner' to 'fowner' to conform to the new LSM conditions posted by Roberto Sassu. - fix calls to ima_log_string() Signed-off-by: Mimi Zohar <zohar@us.ibm.com> Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@intel.com>
2011-03-10 06:25:48 +03:00
dont_appraise fsmagic=0x64626720
# TMPFS_MAGIC
dont_measure fsmagic=0x01021994
ima: add appraise action keywords and default rules Unlike the IMA measurement policy, the appraise policy can not be dependent on runtime process information, such as the task uid, as the 'security.ima' xattr is written on file close and must be updated each time the file changes, regardless of the current task uid. This patch extends the policy language with 'fowner', defines an appraise policy, which appraises all files owned by root, and defines 'ima_appraise_tcb', a new boot command line option, to enable the appraise policy. Changelog v3: - separate the measure from the appraise rules in order to support measuring without appraising and appraising without measuring. - change appraisal default for filesystems without xattr support to fail - update default appraise policy for cgroups Changelog v1: - don't appraise RAMFS (Dmitry Kasatkin) - merged rest of "ima: ima_must_appraise_or_measure API change" commit (Dmtiry Kasatkin) ima_must_appraise_or_measure() called ima_match_policy twice, which searched the policy for a matching rule. Once for a matching measurement rule and subsequently for an appraisal rule. Searching the policy twice is unnecessary overhead, which could be noticeable with a large policy. The new version of ima_must_appraise_or_measure() does everything in a single iteration using a new version of ima_match_policy(). It returns IMA_MEASURE, IMA_APPRAISE mask. With the use of action mask only one efficient matching function is enough. Removed other specific versions of matching functions. Changelog: - change 'owner' to 'fowner' to conform to the new LSM conditions posted by Roberto Sassu. - fix calls to ima_log_string() Signed-off-by: Mimi Zohar <zohar@us.ibm.com> Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@intel.com>
2011-03-10 06:25:48 +03:00
dont_appraise fsmagic=0x01021994
# RAMFS_MAGIC
dont_appraise fsmagic=0x858458f6
# DEVPTS_SUPER_MAGIC
dont_measure fsmagic=0x1cd1
dont_appraise fsmagic=0x1cd1
# BINFMTFS_MAGIC
dont_measure fsmagic=0x42494e4d
dont_appraise fsmagic=0x42494e4d
# SECURITYFS_MAGIC
dont_measure fsmagic=0x73636673
ima: add appraise action keywords and default rules Unlike the IMA measurement policy, the appraise policy can not be dependent on runtime process information, such as the task uid, as the 'security.ima' xattr is written on file close and must be updated each time the file changes, regardless of the current task uid. This patch extends the policy language with 'fowner', defines an appraise policy, which appraises all files owned by root, and defines 'ima_appraise_tcb', a new boot command line option, to enable the appraise policy. Changelog v3: - separate the measure from the appraise rules in order to support measuring without appraising and appraising without measuring. - change appraisal default for filesystems without xattr support to fail - update default appraise policy for cgroups Changelog v1: - don't appraise RAMFS (Dmitry Kasatkin) - merged rest of "ima: ima_must_appraise_or_measure API change" commit (Dmtiry Kasatkin) ima_must_appraise_or_measure() called ima_match_policy twice, which searched the policy for a matching rule. Once for a matching measurement rule and subsequently for an appraisal rule. Searching the policy twice is unnecessary overhead, which could be noticeable with a large policy. The new version of ima_must_appraise_or_measure() does everything in a single iteration using a new version of ima_match_policy(). It returns IMA_MEASURE, IMA_APPRAISE mask. With the use of action mask only one efficient matching function is enough. Removed other specific versions of matching functions. Changelog: - change 'owner' to 'fowner' to conform to the new LSM conditions posted by Roberto Sassu. - fix calls to ima_log_string() Signed-off-by: Mimi Zohar <zohar@us.ibm.com> Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@intel.com>
2011-03-10 06:25:48 +03:00
dont_appraise fsmagic=0x73636673
# SELINUX_MAGIC
dont_measure fsmagic=0xf97cff8c
dont_appraise fsmagic=0xf97cff8c
# CGROUP_SUPER_MAGIC
dont_measure fsmagic=0x27e0eb
dont_appraise fsmagic=0x27e0eb
# NSFS_MAGIC
dont_measure fsmagic=0x6e736673
dont_appraise fsmagic=0x6e736673
measure func=BPRM_CHECK
measure func=FILE_MMAP mask=MAY_EXEC
measure func=FILE_CHECK mask=MAY_READ uid=0
measure func=MODULE_CHECK
measure func=FIRMWARE_CHECK
ima: add appraise action keywords and default rules Unlike the IMA measurement policy, the appraise policy can not be dependent on runtime process information, such as the task uid, as the 'security.ima' xattr is written on file close and must be updated each time the file changes, regardless of the current task uid. This patch extends the policy language with 'fowner', defines an appraise policy, which appraises all files owned by root, and defines 'ima_appraise_tcb', a new boot command line option, to enable the appraise policy. Changelog v3: - separate the measure from the appraise rules in order to support measuring without appraising and appraising without measuring. - change appraisal default for filesystems without xattr support to fail - update default appraise policy for cgroups Changelog v1: - don't appraise RAMFS (Dmitry Kasatkin) - merged rest of "ima: ima_must_appraise_or_measure API change" commit (Dmtiry Kasatkin) ima_must_appraise_or_measure() called ima_match_policy twice, which searched the policy for a matching rule. Once for a matching measurement rule and subsequently for an appraisal rule. Searching the policy twice is unnecessary overhead, which could be noticeable with a large policy. The new version of ima_must_appraise_or_measure() does everything in a single iteration using a new version of ima_match_policy(). It returns IMA_MEASURE, IMA_APPRAISE mask. With the use of action mask only one efficient matching function is enough. Removed other specific versions of matching functions. Changelog: - change 'owner' to 'fowner' to conform to the new LSM conditions posted by Roberto Sassu. - fix calls to ima_log_string() Signed-off-by: Mimi Zohar <zohar@us.ibm.com> Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@intel.com>
2011-03-10 06:25:48 +03:00
appraise fowner=0
The default policy measures all executables in bprm_check,
all files mmapped executable in file_mmap, and all files
ima: add appraise action keywords and default rules Unlike the IMA measurement policy, the appraise policy can not be dependent on runtime process information, such as the task uid, as the 'security.ima' xattr is written on file close and must be updated each time the file changes, regardless of the current task uid. This patch extends the policy language with 'fowner', defines an appraise policy, which appraises all files owned by root, and defines 'ima_appraise_tcb', a new boot command line option, to enable the appraise policy. Changelog v3: - separate the measure from the appraise rules in order to support measuring without appraising and appraising without measuring. - change appraisal default for filesystems without xattr support to fail - update default appraise policy for cgroups Changelog v1: - don't appraise RAMFS (Dmitry Kasatkin) - merged rest of "ima: ima_must_appraise_or_measure API change" commit (Dmtiry Kasatkin) ima_must_appraise_or_measure() called ima_match_policy twice, which searched the policy for a matching rule. Once for a matching measurement rule and subsequently for an appraisal rule. Searching the policy twice is unnecessary overhead, which could be noticeable with a large policy. The new version of ima_must_appraise_or_measure() does everything in a single iteration using a new version of ima_match_policy(). It returns IMA_MEASURE, IMA_APPRAISE mask. With the use of action mask only one efficient matching function is enough. Removed other specific versions of matching functions. Changelog: - change 'owner' to 'fowner' to conform to the new LSM conditions posted by Roberto Sassu. - fix calls to ima_log_string() Signed-off-by: Mimi Zohar <zohar@us.ibm.com> Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@intel.com>
2011-03-10 06:25:48 +03:00
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:
dont_measure obj_type=var_log_t
ima: add appraise action keywords and default rules Unlike the IMA measurement policy, the appraise policy can not be dependent on runtime process information, such as the task uid, as the 'security.ima' xattr is written on file close and must be updated each time the file changes, regardless of the current task uid. This patch extends the policy language with 'fowner', defines an appraise policy, which appraises all files owned by root, and defines 'ima_appraise_tcb', a new boot command line option, to enable the appraise policy. Changelog v3: - separate the measure from the appraise rules in order to support measuring without appraising and appraising without measuring. - change appraisal default for filesystems without xattr support to fail - update default appraise policy for cgroups Changelog v1: - don't appraise RAMFS (Dmitry Kasatkin) - merged rest of "ima: ima_must_appraise_or_measure API change" commit (Dmtiry Kasatkin) ima_must_appraise_or_measure() called ima_match_policy twice, which searched the policy for a matching rule. Once for a matching measurement rule and subsequently for an appraisal rule. Searching the policy twice is unnecessary overhead, which could be noticeable with a large policy. The new version of ima_must_appraise_or_measure() does everything in a single iteration using a new version of ima_match_policy(). It returns IMA_MEASURE, IMA_APPRAISE mask. With the use of action mask only one efficient matching function is enough. Removed other specific versions of matching functions. Changelog: - change 'owner' to 'fowner' to conform to the new LSM conditions posted by Roberto Sassu. - fix calls to ima_log_string() Signed-off-by: Mimi Zohar <zohar@us.ibm.com> Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@intel.com>
2011-03-10 06:25:48 +03:00
dont_appraise obj_type=var_log_t
dont_measure obj_type=auditd_log_t
ima: add appraise action keywords and default rules Unlike the IMA measurement policy, the appraise policy can not be dependent on runtime process information, such as the task uid, as the 'security.ima' xattr is written on file close and must be updated each time the file changes, regardless of the current task uid. This patch extends the policy language with 'fowner', defines an appraise policy, which appraises all files owned by root, and defines 'ima_appraise_tcb', a new boot command line option, to enable the appraise policy. Changelog v3: - separate the measure from the appraise rules in order to support measuring without appraising and appraising without measuring. - change appraisal default for filesystems without xattr support to fail - update default appraise policy for cgroups Changelog v1: - don't appraise RAMFS (Dmitry Kasatkin) - merged rest of "ima: ima_must_appraise_or_measure API change" commit (Dmtiry Kasatkin) ima_must_appraise_or_measure() called ima_match_policy twice, which searched the policy for a matching rule. Once for a matching measurement rule and subsequently for an appraisal rule. Searching the policy twice is unnecessary overhead, which could be noticeable with a large policy. The new version of ima_must_appraise_or_measure() does everything in a single iteration using a new version of ima_match_policy(). It returns IMA_MEASURE, IMA_APPRAISE mask. With the use of action mask only one efficient matching function is enough. Removed other specific versions of matching functions. Changelog: - change 'owner' to 'fowner' to conform to the new LSM conditions posted by Roberto Sassu. - fix calls to ima_log_string() Signed-off-by: Mimi Zohar <zohar@us.ibm.com> Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@intel.com>
2011-03-10 06:25:48 +03:00
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