Re: [PATCH v5 02/10] IMA: Added keyrings= option in IMA policy to only measure keys added to the specified keyrings.
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From: Mimi Zohar <zohar@linux.ibm.com>
Date: 2019-11-12 17:05:16
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keyrings, linux-integrity, lkml
The C maximum line length is 80 characters. The subject line is even less than that (~50). The Subject line here could be "ima: add support to limit measuring keys". On Mon, 2019-11-11 at 11:32 -0800, Lakshmi Ramasubramanian wrote:
IMA policy needs to support measuring only those keys linked to a specific set of keyrings.
Patch descriptions should be written in the imperative. For example, "Limit measuring keys to those keys being loaded onto a specific keyring."
This patch defines a new IMA policy option namely "keyrings=" that can be used to specify a set of keyrings. If this option is specified in the policy for func=KEYRING_CHECK then only the keys linked to the keyrings given in "keyrings=" option are measured.
This description does not seem to match the code, which for some reason isn't included in this patch, nor in 3/10. Please combine/squash patches 2 & 3. Missing from the combined patch is the keyring matching code in ima_match_rules().
If "keyrings=" option is not specified for func=KEYRING_CHECK then all keys are measured.
The last sentence is unnecessary. Please remove.
quoted hunk ↗ jump to hunk
Signed-off-by: Lakshmi Ramasubramanian <redacted> --- Documentation/ABI/testing/ima_policy | 10 +++++++++- security/integrity/ima/ima_policy.c | 2 ++ 2 files changed, 11 insertions(+), 1 deletion(-)diff --git a/Documentation/ABI/testing/ima_policy b/Documentation/ABI/testing/ima_policy index 341df49b5ad1..be2874fa3928 100644 --- a/Documentation/ABI/testing/ima_policy +++ b/Documentation/ABI/testing/ima_policy@@ -25,7 +25,7 @@ Description: lsm: [[subj_user=] [subj_role=] [subj_type=] [obj_user=] [obj_role=] [obj_type=]] option: [[appraise_type=]] [template=] [permit_directio] - [appraise_flag=] + [appraise_flag=] [keyrings=] base: func:= [BPRM_CHECK][MMAP_CHECK][CREDS_CHECK][FILE_CHECK][MODULE_CHECK] [FIRMWARE_CHECK] [KEXEC_KERNEL_CHECK] [KEXEC_INITRAMFS_CHECK]@@ -43,6 +43,9 @@ Description: appraise_flag:= [check_blacklist] Currently, blacklist check is only for files signed with appended signature. + keyrings:= list of keyrings + (eg, .builtin_trusted_keys|.ima). Only valid + when action is "measure" and func is KEYRING_CHECK. template:= name of a defined IMA template type (eg, ima-ng). Only valid when action is "measure". pcr:= decimal value@@ -119,3 +122,8 @@ Description: all keys: measure func=KEYRING_CHECK + + Example of measure rule using KEYRING_CHECK to only measure + keys added to .builtin_trusted_keys or .ima keyring: + + measure func=KEYRING_CHECK keyrings=.builtin_trusted_keys|.imadiff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c index 9ca32ffaaa9d..a0f7ffa80736 100644 --- a/security/integrity/ima/ima_policy.c +++ b/security/integrity/ima/ima_policy.c@@ -34,6 +34,7 @@ #define IMA_EUID 0x0080 #define IMA_PCR 0x0100 #define IMA_FSNAME 0x0200 +#define IMA_KEYRINGS 0x0400 #define UNKNOWN 0 #define MEASURE 0x0001 /* same as IMA_MEASURE */@@ -79,6 +80,7 @@ struct ima_rule_entry { int type; /* audit type */ } lsm[MAX_LSM_RULES]; char *fsname; + char *keyrings; /* Measure keys added to these keyrings */ struct ima_template_desc *template; };