2020-07-27 14:41:31

by Tyler Hicks

Subject: [PATCH 2/2] ima: Fail rule parsing when asymmetric key measurement isn't supportable

Measuring keys is currently only supported for asymmetric keys. In the
future, this might change.

For now, the "func=KEY_CHECK" and "keyrings=" options are only
appropriate when CONFIG_IMA_MEASURE_ASYMMETRIC_KEYS is enabled. Make
this clear at policy load so that IMA policy authors don't assume that
these policy language constructs are supported.

Fixes: 2b60c0ecedf8 ("IMA: Read keyrings= option from the IMA policy")
Fixes: 5808611cccb2 ("IMA: Add KEY_CHECK func to measure keys")
Suggested-by: Nayna Jain <[email protected]>
Signed-off-by: Tyler Hicks <[email protected]>
---
security/integrity/ima/ima_policy.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
index c328cfa0fc49..05f012fd3dca 100644
--- a/security/integrity/ima/ima_policy.c
+++ b/security/integrity/ima/ima_policy.c
@@ -1233,7 +1233,8 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
entry->func = POLICY_CHECK;
else if (strcmp(args[0].from, "KEXEC_CMDLINE") == 0)
entry->func = KEXEC_CMDLINE;
- else if (strcmp(args[0].from, "KEY_CHECK") == 0)
+ else if (IS_ENABLED(CONFIG_IMA_MEASURE_ASYMMETRIC_KEYS) &&
+ strcmp(args[0].from, "KEY_CHECK") == 0)
entry->func = KEY_CHECK;
else
result = -EINVAL;
@@ -1290,7 +1291,8 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
case Opt_keyrings:
ima_log_string(ab, "keyrings", args[0].from);

- if (entry->keyrings) {
+ if (!IS_ENABLED(CONFIG_IMA_MEASURE_ASYMMETRIC_KEYS) ||
+ entry->keyrings) {
result = -EINVAL;
break;
}
--
2.25.1

2020-07-28 14:15:39

by Lakshmi Ramasubramanian

Subject: Re: [PATCH 2/2] ima: Fail rule parsing when asymmetric key measurement isn't supportable

On 7/27/20 7:08 AM, Tyler Hicks wrote:
> Measuring keys is currently only supported for asymmetric keys. In the
> future, this might change.
>
> For now, the "func=KEY_CHECK" and "keyrings=" options are only
> appropriate when CONFIG_IMA_MEASURE_ASYMMETRIC_KEYS is enabled. Make
> this clear at policy load so that IMA policy authors don't assume that
> these policy language constructs are supported.
>
> Fixes: 2b60c0ecedf8 ("IMA: Read keyrings= option from the IMA policy")
> Fixes: 5808611cccb2 ("IMA: Add KEY_CHECK func to measure keys")
> Suggested-by: Nayna Jain <[email protected]>
> Signed-off-by: Tyler Hicks <[email protected]>
> ---
> security/integrity/ima/ima_policy.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
> index c328cfa0fc49..05f012fd3dca 100644
> --- a/security/integrity/ima/ima_policy.c
> +++ b/security/integrity/ima/ima_policy.c
> @@ -1233,7 +1233,8 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
> entry->func = POLICY_CHECK;
> else if (strcmp(args[0].from, "KEXEC_CMDLINE") == 0)
> entry->func = KEXEC_CMDLINE;
> - else if (strcmp(args[0].from, "KEY_CHECK") == 0)
> + else if (IS_ENABLED(CONFIG_IMA_MEASURE_ASYMMETRIC_KEYS) &&
> + strcmp(args[0].from, "KEY_CHECK") == 0)
> entry->func = KEY_CHECK;
> else
> result = -EINVAL;
> @@ -1290,7 +1291,8 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
> case Opt_keyrings:
> ima_log_string(ab, "keyrings", args[0].from);
>
> - if (entry->keyrings) {
> + if (!IS_ENABLED(CONFIG_IMA_MEASURE_ASYMMETRIC_KEYS) ||
> + entry->keyrings) {
> result = -EINVAL;
> break;
> }
>

Reviewed-by: Lakshmi Ramasubramanian <[email protected]>