On 2020-12-09 11:42:09, Tushar Sugandhi wrote:
> System administrators should be able to limit which kernel subsystems
> they want to measure the critical data for. To enable that, an IMA policy
> condition to choose specific kernel subsystems is needed. This policy
> condition would constrain the measurement of the critical data based on
> a label for the given subsystems.
>
> Add a new IMA policy condition - "data_source:=" to the IMA func
> CRITICAL_DATA to allow measurement of various kernel subsystems. This
> policy condition would enable the system administrators to restrict the
> measurement to the labels listed in "data_source:=".
>
> Limit the measurement to the labels that are specified in the IMA
> policy - CRITICAL_DATA+"data_source:=". If "data_sources:=" is not
> provided with the func CRITICAL_DATA, the data from all the
> supported kernel subsystems is measured.
>
> Signed-off-by: Tushar Sugandhi <tusharsu@xxxxxxxxxxxxxxxxxxx>
This patch will look good once all the IMA_DATA_SOURCE stuff is moved
over from patch #4.
Tyler
> ---
> Documentation/ABI/testing/ima_policy | 2 ++
> security/integrity/ima/ima_policy.c | 26 +++++++++++++++++++++++++-
> 2 files changed, 27 insertions(+), 1 deletion(-)
>
> diff --git a/Documentation/ABI/testing/ima_policy b/Documentation/ABI/testing/ima_policy
> index 6ec7daa87cba..0f4ee9e0a455 100644
> --- a/Documentation/ABI/testing/ima_policy
> +++ b/Documentation/ABI/testing/ima_policy
> @@ -52,6 +52,8 @@ Description:
> template:= name of a defined IMA template type
> (eg, ima-ng). Only valid when action is "measure".
> pcr:= decimal value
> + data_source:= [label]
> + label:= a unique string used for grouping and limiting critical data.
>
> default policy:
> # PROC_SUPER_MAGIC
> diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
> index 9a8ee80a3128..7486d09a3f60 100644
> --- a/security/integrity/ima/ima_policy.c
> +++ b/security/integrity/ima/ima_policy.c
> @@ -934,7 +934,7 @@ enum {
> Opt_uid_lt, Opt_euid_lt, Opt_fowner_lt,
> Opt_appraise_type, Opt_appraise_flag,
> Opt_permit_directio, Opt_pcr, Opt_template, Opt_keyrings,
> - Opt_err
> + Opt_data_source, Opt_err
> };
>
> static const match_table_t policy_tokens = {
> @@ -971,6 +971,7 @@ static const match_table_t policy_tokens = {
> {Opt_pcr, "pcr=%s"},
> {Opt_template, "template=%s"},
> {Opt_keyrings, "keyrings=%s"},
> + {Opt_data_source, "data_source=%s"},
> {Opt_err, NULL}
> };
>
> @@ -1350,6 +1351,23 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
>
> entry->flags |= IMA_KEYRINGS;
> break;
> + case Opt_data_source:
> + ima_log_string(ab, "data_source", args[0].from);
> +
> + if (entry->data_source) {
> + result = -EINVAL;
> + break;
> + }
> +
> + entry->data_source = ima_alloc_rule_opt_list(args);
> + if (IS_ERR(entry->data_source)) {
> + result = PTR_ERR(entry->data_source);
> + entry->data_source = NULL;
> + break;
> + }
> +
> + entry->flags |= IMA_DATA_SOURCE;
> + break;
> case Opt_fsuuid:
> ima_log_string(ab, "fsuuid", args[0].from);
>
> @@ -1730,6 +1748,12 @@ int ima_policy_show(struct seq_file *m, void *v)
> seq_puts(m, " ");
> }
>
> + if (entry->flags & IMA_DATA_SOURCE) {
> + seq_puts(m, "data_source=");
> + ima_show_rule_opt_list(m, entry->data_source);
> + seq_puts(m, " ");
> + }
> +
> if (entry->flags & IMA_PCR) {
> snprintf(tbuf, sizeof(tbuf), "%d", entry->pcr);
> seq_printf(m, pt(Opt_pcr), tbuf);
> --
> 2.17.1
>
