Re: [PATCH v5 01/10] IMA: Added KEYRING_CHECK func in IMA policy to measure keys

Mimi Zohar
2019-11-12T17:05:08Z

On Mon, 2019-11-11 at 11:32 -0800, Lakshmi Ramasubramanian wrote:
> IMA policy needs to support a func to enable measurement of
> asymmetric keys.
>
> This patch defines a new IMA policy func namely KEYRING_CHECK to
> measure asymmetric keys.

This new feature measures "keys" based on policy, not "keyrings".
Please change the name to KEY_CHECK.

>
> Signed-off-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
> ---
> Documentation/ABI/testing/ima_policy | 6 ++++++
> security/integrity/ima/ima.h | 1 +
> security/integrity/ima/ima_policy.c | 4 +++-
> 3 files changed, 10 insertions(+), 1 deletion(-)
>
> diff --git a/Documentation/ABI/testing/ima_policy b/Documentation/ABI/testing/ima_policy
> index 29aaedf33246..341df49b5ad1 100644
> --- a/Documentation/ABI/testing/ima_policy
> +++ b/Documentation/ABI/testing/ima_policy
> @@ -30,6 +30,7 @@ Description:
> [FIRMWARE_CHECK]
> [KEXEC_KERNEL_CHECK] [KEXEC_INITRAMFS_CHECK]
> [KEXEC_CMDLINE]
> + [KEYRING_CHECK]
> mask:= [[^]MAY_READ] [[^]MAY_WRITE] [[^]MAY_APPEND]
> [[^]MAY_EXEC]
> fsmagic:= hex value
> @@ -113,3 +114,8 @@ Description:
> Example of appraise rule allowing modsig appended signatures:
>
> appraise func=KEXEC_KERNEL_CHECK appraise_type=imasig|modsig
> +
> + Example of measure rule using KEYRING_CHECK to measure
> + all keys:
> +
> + measure func=KEYRING_CHECK
> diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
> index df4ca482fb53..7f23405b2718 100644
> --- a/security/integrity/ima/ima.h
> +++ b/security/integrity/ima/ima.h
> @@ -193,6 +193,7 @@ static inline unsigned long ima_hash_key(u8 *digest)
> hook(KEXEC_INITRAMFS_CHECK) \
> hook(POLICY_CHECK) \
> hook(KEXEC_CMDLINE) \
> + hook(KEYRING_CHECK) \
> hook(MAX_CHECK)
> #define __ima_hook_enumify(ENUM) ENUM,
>
> diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
> index f19a895ad7cd..9ca32ffaaa9d 100644
> --- a/security/integrity/ima/ima_policy.c
> +++ b/security/integrity/ima/ima_policy.c
> @@ -373,7 +373,7 @@ static bool ima_match_rules(struct ima_rule_entry *rule, struct inode *inode,
> {
> int i;
>
> - if (func == KEXEC_CMDLINE) {
> + if ((func == KEXEC_CMDLINE) || (func == KEYRING_CHECK)) {
> if ((rule->flags & IMA_FUNC) && (rule->func == func))
> return true;
> return false;
> @@ -997,6 +997,8 @@ 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, "KEYRING_CHECK") == 0)
> + entry->func = KEYRING_CHECK;
> else
> result = -EINVAL;
> if (!result)