Hi Lakshmi,
I haven't yet tested the patch. Below are a couple of comments.
On Wed, 2020-06-10 at 17:04 -0700, Lakshmi Ramasubramanian wrote:
> The final log statement in process_buffer_measurement() for failure
> condition is at debug level. This does not log the message unless
> the system log level is raised which would significantly increase
> the messages in the system log. Change this to an audit message to
> audit integrity failures with the "op" field of the audit message
> set to indicate the measurement operation that failed.
The problem with the existing "pr" level is kind of irrelevant. You
could keep the existing pr_debug() statement, if you wanted to. The
reason for auditing a failure is because it is "integrity" relevant or
more generically "security" relevant. The first patch addresses the
change in the audit message format.
>
> Also, add an audit message for failures in ima_alloc_key_entry().
>
> Sample audit messages:
>
> [ 6.284329] audit: type=1804 audit(1591756723.627:2): pid=1 uid=0
> auid=4294967295 ses=4294967295 subj=kernel
> op=measuring_kexec_cmdline cause=alloc_entry errno=-12
> comm="swapper/0" name="kexec-cmdline" res=0
>
> [ 8.017126] audit: type=1804 audit(1591756725.360:10): pid=1
> uid=0 auid=4294967295 ses=4294967295
> subj=system_u:system_r:init_t:s0 op=measuring_key
> cause=hashing_error errno=-22 comm="systemd"
> name=".builtin_trusted_keys" res=0
>
> Signed-off-by: Lakshmi Ramasubramanian <nramas@xxxxxxxxxxxxxxxxxxx>
> Suggested-by: Mimi Zohar <zohar@xxxxxxxxxxxxx>
> ---
> security/integrity/ima/ima.h | 48 ++++++++++++++++---------
> security/integrity/ima/ima_main.c | 18 +++++++---
> security/integrity/ima/ima_policy.c | 2 +-
> security/integrity/ima/ima_queue_keys.c | 5 +++
> 4 files changed, 51 insertions(+), 22 deletions(-)
>
> diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
> index df93ac258e01..e42101eebd69 100644
> --- a/security/integrity/ima/ima.h
> +++ b/security/integrity/ima/ima.h
> @@ -186,27 +186,43 @@ static inline unsigned int ima_hash_key(u8 *digest)
> return (digest[0] | digest[1] << 8) % IMA_MEASURE_HTABLE_SIZE;
> }
>
> -#define __ima_hooks(hook) \
> - hook(NONE) \
> - hook(FILE_CHECK) \
> - hook(MMAP_CHECK) \
> - hook(BPRM_CHECK) \
> - hook(CREDS_CHECK) \
> - hook(POST_SETATTR) \
> - hook(MODULE_CHECK) \
> - hook(FIRMWARE_CHECK) \
> - hook(KEXEC_KERNEL_CHECK) \
> - hook(KEXEC_INITRAMFS_CHECK) \
> - hook(POLICY_CHECK) \
> - hook(KEXEC_CMDLINE) \
> - hook(KEY_CHECK) \
> - hook(MAX_CHECK)
> -#define __ima_hook_enumify(ENUM) ENUM,
> +#define __ima_hooks(hook) \
> + hook(NONE, none) \
> + hook(FILE_CHECK, file) \
> + hook(MMAP_CHECK, mmap) \
> + hook(BPRM_CHECK, bprm) \
> + hook(CREDS_CHECK, creds) \
> + hook(POST_SETATTR, post_setattr) \
> + hook(MODULE_CHECK, module) \
> + hook(FIRMWARE_CHECK, firmware) \
> + hook(KEXEC_KERNEL_CHECK, kexec_kernel) \
> + hook(KEXEC_INITRAMFS_CHECK, kexec_initramfs) \
> + hook(POLICY_CHECK, policy) \
> + hook(KEXEC_CMDLINE, kexec_cmdline) \
> + hook(KEY_CHECK, key) \
> + hook(MAX_CHECK, none)
> +
> +#define __ima_hook_enumify(ENUM, str) ENUM,
> +#define __ima_stringify(arg) (#arg)
> +#define __ima_hook_measuring_stringify(ENUM, str) \
> + (__ima_stringify(measuring_ ##str)),
>
> enum ima_hooks {
> __ima_hooks(__ima_hook_enumify)
> };
>
> +static const char * const ima_hooks_measure_str[] = {
> + __ima_hooks(__ima_hook_measuring_stringify)
> +};
> +
> +static inline const char *ima_hooks_func_measure_str(enum ima_hooks func)
"ima_hooks_func_measure_str" is a bit long. There's no reason for
having both "hooks" and "func" in the name. Also this is a static
function, so it doesn't really need to be prefixed with "ima_". Maybe
truncate it to "func_measure_str()", similar to "func_token".
Mimi
> +{
> + if (func >= MAX_CHECK)
> + return ima_hooks_measure_str[NONE];
> +
> + return ima_hooks_measure_str[func];
> +}
> +
> extern const char *const func_tokens[];
