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author | Mimi Zohar <zohar@linux.vnet.ibm.com> | 2017-04-22 01:58:27 +0300 |
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committer | Mimi Zohar <zohar@linux.vnet.ibm.com> | 2017-06-21 21:37:12 +0300 |
commit | 503ceaef8e2e7dbbdb04a867acc6fe4c548ede7f (patch) | |
tree | 8657ab63e5546d352bdc1c4ffaa420d75b701d94 /security/integrity/ima | |
parent | 33ce9549cfa1e71d77bc91a2e67e65d693e2e53f (diff) | |
download | linux-503ceaef8e2e7dbbdb04a867acc6fe4c548ede7f.tar.xz |
ima: define a set of appraisal rules requiring file signatures
The builtin "ima_appraise_tcb" policy should require file signatures for
at least a few of the hooks (eg. kernel modules, firmware, and the kexec
kernel image), but changing it would break the existing userspace/kernel
ABI.
This patch defines a new builtin policy named "secure_boot", which
can be specified on the "ima_policy=" boot command line, independently
or in conjunction with the "ima_appraise_tcb" policy, by specifing
ima_policy="appraise_tcb | secure_boot". The new appraisal rules
requiring file signatures will be added prior to the "ima_appraise_tcb"
rules.
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Changelog:
- Reference secure boot in the new builtin policy name. (Thiago Bauermann)
Diffstat (limited to 'security/integrity/ima')
-rw-r--r-- | security/integrity/ima/ima_policy.c | 26 |
1 files changed, 25 insertions, 1 deletions
diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c index 0ddc41389a9c..3653c86c70df 100644 --- a/security/integrity/ima/ima_policy.c +++ b/security/integrity/ima/ima_policy.c @@ -153,6 +153,17 @@ static struct ima_rule_entry default_appraise_rules[] __ro_after_init = { #endif }; +static struct ima_rule_entry secure_boot_rules[] __ro_after_init = { + {.action = APPRAISE, .func = MODULE_CHECK, + .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED}, + {.action = APPRAISE, .func = FIRMWARE_CHECK, + .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED}, + {.action = APPRAISE, .func = KEXEC_KERNEL_CHECK, + .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED}, + {.action = APPRAISE, .func = POLICY_CHECK, + .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED}, +}; + static LIST_HEAD(ima_default_rules); static LIST_HEAD(ima_policy_rules); static LIST_HEAD(ima_temp_rules); @@ -171,6 +182,7 @@ static int __init default_measure_policy_setup(char *str) __setup("ima_tcb", default_measure_policy_setup); static bool ima_use_appraise_tcb __initdata; +static bool ima_use_secure_boot __initdata; static int __init policy_setup(char *str) { char *p; @@ -182,6 +194,8 @@ static int __init policy_setup(char *str) ima_policy = DEFAULT_TCB; else if (strcmp(p, "appraise_tcb") == 0) ima_use_appraise_tcb = 1; + else if (strcmp(p, "secure_boot") == 0) + ima_use_secure_boot = 1; } return 1; @@ -410,12 +424,14 @@ void ima_update_policy_flag(void) */ void __init ima_init_policy(void) { - int i, measure_entries, appraise_entries; + int i, measure_entries, appraise_entries, secure_boot_entries; /* if !ima_policy set entries = 0 so we load NO default rules */ measure_entries = ima_policy ? ARRAY_SIZE(dont_measure_rules) : 0; appraise_entries = ima_use_appraise_tcb ? ARRAY_SIZE(default_appraise_rules) : 0; + secure_boot_entries = ima_use_secure_boot ? + ARRAY_SIZE(secure_boot_rules) : 0; for (i = 0; i < measure_entries; i++) list_add_tail(&dont_measure_rules[i].list, &ima_default_rules); @@ -434,6 +450,14 @@ void __init ima_init_policy(void) break; } + /* + * Insert the appraise rules requiring file signatures, prior to + * any other appraise rules. + */ + for (i = 0; i < secure_boot_entries; i++) + list_add_tail(&secure_boot_rules[i].list, + &ima_default_rules); + for (i = 0; i < appraise_entries; i++) { list_add_tail(&default_appraise_rules[i].list, &ima_default_rules); |