mirror of
https://github.com/torvalds/linux.git
synced 2024-12-25 20:32:22 +00:00
d9ddf077bb
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>
99 lines
3.2 KiB
Plaintext
99 lines
3.2 KiB
Plaintext
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 [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]
|
|
[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
|
|
fowner:=decimal value
|
|
lsm: are LSM specific
|
|
option: appraise_type:= [imasig]
|
|
|
|
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_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
|
|
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
|
|
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:
|
|
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
|