Re: [PATCH v1 3/6] KEYS: ima hook to measure builtin_trusted_keys

Mimi Zohar
2019-10-23T13:22:25Z

On Tue, 2019-10-22 at 17:18 -0700, Lakshmi Ramasubramanian wrote:
> Add a new ima hook to measure keys added to builtin_trusted_keys
> keyring.

There is no IMA hook in this patch.

>
> Updated ima_match_rules function to handle the new ima hook.
> This is used to determine if ima policy requires measurement
> of keys added to builtin_trusted_keys keyring.
>
> Signed-off-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
> ---
> Documentation/ABI/testing/ima_policy | 1 +
> security/integrity/ima/ima.h | 1 +
> security/integrity/ima/ima_api.c | 1 +
> security/integrity/ima/ima_policy.c | 5 ++++-
> 4 files changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/Documentation/ABI/testing/ima_policy b/Documentation/ABI/testing/ima_policy
> index fc376a323908..25566c74e679 100644
> --- a/Documentation/ABI/testing/ima_policy
> +++ b/Documentation/ABI/testing/ima_policy
> @@ -29,6 +29,7 @@ Description:
> [FIRMWARE_CHECK]
> [KEXEC_KERNEL_CHECK] [KEXEC_INITRAMFS_CHECK]
> [KEXEC_CMDLINE]
> + [BUILTIN_TRUSTED_KEYS]
> mask:= [[^]MAY_READ] [[^]MAY_WRITE] [[^]MAY_APPEND]
> [[^]MAY_EXEC]
> fsmagic:= hex value
> diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
> index b6847ee1f47a..0d2908036882 100644
> --- a/security/integrity/ima/ima.h
> +++ b/security/integrity/ima/ima.h
> @@ -189,6 +189,7 @@ static inline unsigned long ima_hash_key(u8 *digest)
> hook(KEXEC_INITRAMFS_CHECK) \
> hook(POLICY_CHECK) \
> hook(KEXEC_CMDLINE) \
> + hook(BUILTIN_TRUSTED_KEYS) \
> hook(MAX_CHECK)
> #define __ima_hook_enumify(ENUM) ENUM,
>
> diff --git a/security/integrity/ima/ima_api.c b/security/integrity/ima/ima_api.c
> index f614e22bf39f..cc04706b7e7a 100644
> --- a/security/integrity/ima/ima_api.c
> +++ b/security/integrity/ima/ima_api.c
> @@ -175,6 +175,7 @@ void ima_add_violation(struct file *file, const unsigned char *filename,
> * subj,obj, and type: are LSM specific.
> * func: FILE_CHECK | BPRM_CHECK | CREDS_CHECK | MMAP_CHECK | MODULE_CHECK
> * | KEXEC_CMDLINE
> + * | BUILTIN_TRUSTED_KEYS
> * mask: contains the permission mask
> * fsmagic: hex value
> *
> diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
> index 6df7f641ff66..944636076152 100644
> --- a/security/integrity/ima/ima_policy.c
> +++ b/security/integrity/ima/ima_policy.c
> @@ -370,7 +370,7 @@ static bool ima_match_rules(struct ima_rule_entry *rule, struct inode *inode,
> {
> int i;
>
> - if (func == KEXEC_CMDLINE) {
> + if ((func == KEXEC_CMDLINE) || (func == BUILTIN_TRUSTED_KEYS)) {
> if ((rule->flags & IMA_FUNC) && (rule->func == func))
> return true;
> return false;
> @@ -959,6 +959,9 @@ 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,
> + "BUILTIN_TRUSTED_KEYS") == 0)
> + entry->func = BUILTIN_TRUSTED_KEYS;
> else
> result = -EINVAL;
> if (!result)

Any new options need to be displayed as well.

Mimi