ima: add policy support for extending different pcrs
This patch defines a new IMA measurement policy rule option "pcr=",
which allows extending different PCRs on a per rule basis. For example,
the system independent files could extend the default IMA Kconfig
specified PCR, while the system dependent files could extend a different
PCR.
The following is an example of this usage with an SELinux policy; the
rule would extend PCR 11 with system configuration files:
measure func=FILE_CHECK mask=MAY_READ obj_type=system_conf_t pcr=11
Changelog v3:
- FIELD_SIZEOF returns bytes, not bits. Fixed INVALID_PCR
Signed-off-by: Eric Richter <erichte@linux.vnet.ibm.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
index 0f887a5..3d35fbe 100644
--- a/security/integrity/ima/ima_policy.c
+++ b/security/integrity/ima/ima_policy.c
@@ -32,6 +32,7 @@
#define IMA_FSUUID 0x0020
#define IMA_INMASK 0x0040
#define IMA_EUID 0x0080
+#define IMA_PCR 0x0100
#define UNKNOWN 0
#define MEASURE 0x0001 /* same as IMA_MEASURE */
@@ -40,6 +41,9 @@
#define DONT_APPRAISE 0x0008
#define AUDIT 0x0040
+#define INVALID_PCR(a) (((a) < 0) || \
+ (a) >= (FIELD_SIZEOF(struct integrity_iint_cache, measured_pcrs) * 8))
+
int ima_policy_flag;
static int temp_ima_appraise;
@@ -60,6 +64,7 @@
u8 fsuuid[16];
kuid_t uid;
kuid_t fowner;
+ int pcr;
struct {
void *rule; /* LSM file metadata specific */
void *args_p; /* audit value */
@@ -478,7 +483,8 @@
Opt_subj_user, Opt_subj_role, Opt_subj_type,
Opt_func, Opt_mask, Opt_fsmagic,
Opt_fsuuid, Opt_uid, Opt_euid, Opt_fowner,
- Opt_appraise_type, Opt_permit_directio
+ Opt_appraise_type, Opt_permit_directio,
+ Opt_pcr
};
static match_table_t policy_tokens = {
@@ -502,6 +508,7 @@
{Opt_fowner, "fowner=%s"},
{Opt_appraise_type, "appraise_type=%s"},
{Opt_permit_directio, "permit_directio"},
+ {Opt_pcr, "pcr=%s"},
{Opt_err, NULL}
};
@@ -774,6 +781,20 @@
case Opt_permit_directio:
entry->flags |= IMA_PERMIT_DIRECTIO;
break;
+ case Opt_pcr:
+ if (entry->action != MEASURE) {
+ result = -EINVAL;
+ break;
+ }
+ ima_log_string(ab, "pcr", args[0].from);
+
+ result = kstrtoint(args[0].from, 10, &entry->pcr);
+ if (result || INVALID_PCR(entry->pcr))
+ result = -EINVAL;
+ else
+ entry->flags |= IMA_PCR;
+
+ break;
case Opt_err:
ima_log_string(ab, "UNKNOWN", p);
result = -EINVAL;
@@ -1011,6 +1032,12 @@
seq_puts(m, " ");
}
+ if (entry->flags & IMA_PCR) {
+ snprintf(tbuf, sizeof(tbuf), "%d", entry->pcr);
+ seq_printf(m, pt(Opt_pcr), tbuf);
+ seq_puts(m, " ");
+ }
+
if (entry->flags & IMA_FSUUID) {
seq_printf(m, "fsuuid=%pU", entry->fsuuid);
seq_puts(m, " ");