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authorLakshmi Ramasubramanian <nramas@linux.microsoft.com>2019-12-11 08:47:07 -0800
committerMimi Zohar <zohar@linux.ibm.com>2019-12-12 08:53:50 -0500
commit2b60c0ecedf8d43b35a3c8554e72e8daca93fbcf (patch)
treef915be6917614dd8cb67d9aae697740551b35f73 /security/integrity
parente9085e0ad38a333012629d815c203155d61ebe7e (diff)
IMA: Read keyrings= option from the IMA policy
Read "keyrings=" option, if specified in the IMA policy, and store in the list of IMA rules when the configured IMA policy is read. This patch defines a new policy token enum namely Opt_keyrings and an option flag IMA_KEYRINGS for reading "keyrings=" option from the IMA policy. Updated ima_parse_rule() to parse "keyrings=" option in the policy. Updated ima_policy_show() to display "keyrings=" option. The following example illustrates how key measurement can be verified. Sample "key" measurement rule in the IMA policy: measure func=KEY_CHECK uid=0 keyrings=.ima|.evm template=ima-buf Display "key" measurement in the IMA measurement list: cat /sys/kernel/security/ima/ascii_runtime_measurements 10 faf3...e702 ima-buf sha256:27c915b8ddb9fae7214cf0a8a7043cc3eeeaa7539bcb136f8427067b5f6c3b7b .ima 308202863082...4aee Verify "key" measurement data for a key added to ".ima" keyring: cat /sys/kernel/security/integrity/ima/ascii_runtime_measurements | grep -m 1 "\.ima" | cut -d' ' -f 6 | xxd -r -p |tee ima-cert.der | sha256sum | cut -d' ' -f 1 The output of the above command should match the template hash of the first "key" measurement entry in the IMA measurement list for the key added to ".ima" keyring. The file namely "ima-cert.der" generated by the above command should be a valid x509 certificate (in DER format) and should match the one that was used to import the key to the ".ima" keyring. The certificate file can be verified using openssl tool. Signed-off-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com> Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
Diffstat (limited to 'security/integrity')
-rw-r--r--security/integrity/ima/ima_policy.c29
1 files changed, 28 insertions, 1 deletions
diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
index cca87c499c4f..a4dde9d575b2 100644
--- a/security/integrity/ima/ima_policy.c
+++ b/security/integrity/ima/ima_policy.c
@@ -34,6 +34,7 @@
#define IMA_EUID 0x0080
#define IMA_PCR 0x0100
#define IMA_FSNAME 0x0200
+#define IMA_KEYRINGS 0x0400
#define UNKNOWN 0
#define MEASURE 0x0001 /* same as IMA_MEASURE */
@@ -820,7 +821,8 @@ enum {
Opt_uid_gt, Opt_euid_gt, Opt_fowner_gt,
Opt_uid_lt, Opt_euid_lt, Opt_fowner_lt,
Opt_appraise_type, Opt_appraise_flag,
- Opt_permit_directio, Opt_pcr, Opt_template, Opt_err
+ Opt_permit_directio, Opt_pcr, Opt_template, Opt_keyrings,
+ Opt_err
};
static const match_table_t policy_tokens = {
@@ -856,6 +858,7 @@ static const match_table_t policy_tokens = {
{Opt_permit_directio, "permit_directio"},
{Opt_pcr, "pcr=%s"},
{Opt_template, "template=%s"},
+ {Opt_keyrings, "keyrings=%s"},
{Opt_err, NULL}
};
@@ -1105,6 +1108,23 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
result = 0;
entry->flags |= IMA_FSNAME;
break;
+ case Opt_keyrings:
+ ima_log_string(ab, "keyrings", args[0].from);
+
+ if ((entry->keyrings) ||
+ (entry->action != MEASURE) ||
+ (entry->func != KEY_CHECK)) {
+ result = -EINVAL;
+ break;
+ }
+ entry->keyrings = kstrdup(args[0].from, GFP_KERNEL);
+ if (!entry->keyrings) {
+ result = -ENOMEM;
+ break;
+ }
+ result = 0;
+ entry->flags |= IMA_KEYRINGS;
+ break;
case Opt_fsuuid:
ima_log_string(ab, "fsuuid", args[0].from);
@@ -1480,6 +1500,13 @@ int ima_policy_show(struct seq_file *m, void *v)
seq_puts(m, " ");
}
+ if (entry->flags & IMA_KEYRINGS) {
+ if (entry->keyrings != NULL)
+ snprintf(tbuf, sizeof(tbuf), "%s", entry->keyrings);
+ seq_printf(m, pt(Opt_keyrings), tbuf);
+ seq_puts(m, " ");
+ }
+
if (entry->flags & IMA_PCR) {
snprintf(tbuf, sizeof(tbuf), "%d", entry->pcr);
seq_printf(m, pt(Opt_pcr), tbuf);