lsm: [[subj_user=] [subj_role=] [subj_type=]
[obj_user=] [obj_role=] [obj_type=]]
option: [[appraise_type=]] [template=] [permit_directio]
- [appraise_flag=]
+ [appraise_flag=] [keyrings=]
base: func:= [BPRM_CHECK][MMAP_CHECK][CREDS_CHECK][FILE_CHECK][MODULE_CHECK]
[FIRMWARE_CHECK]
[KEXEC_KERNEL_CHECK] [KEXEC_INITRAMFS_CHECK]
appraise_flag:= [check_blacklist]
Currently, blacklist check is only for files signed with appended
signature.
+ keyrings:= list of keyrings
+ (eg, .builtin_trusted_keys|.ima). Only valid
+ when action is "measure" and func is KEY_CHECK.
template:= name of a defined IMA template type
(eg, ima-ng). Only valid when action is "measure".
pcr:= decimal value
Example of measure rule using KEY_CHECK to measure all keys:
measure func=KEY_CHECK
+
+ Example of measure rule using KEY_CHECK to only measure
+ keys added to .builtin_trusted_keys or .ima keyring:
+
+ measure func=KEY_CHECK keyrings=.builtin_trusted_keys|.ima
/* LIM API function definitions */
int ima_get_action(struct inode *inode, const struct cred *cred, u32 secid,
int mask, enum ima_hooks func, int *pcr,
- struct ima_template_desc **template_desc);
+ struct ima_template_desc **template_desc,
+ const char *keyring);
int ima_must_measure(struct inode *inode, int mask, enum ima_hooks func);
int ima_collect_measurement(struct integrity_iint_cache *iint,
struct file *file, void *buf, loff_t size,
struct ima_template_desc *template_desc);
void process_buffer_measurement(const void *buf, int size,
const char *eventname, enum ima_hooks func,
- int pcr);
+ int pcr, const char *keyring);
void ima_audit_measurement(struct integrity_iint_cache *iint,
const unsigned char *filename);
int ima_alloc_init_template(struct ima_event_data *event_data,
/* IMA policy related functions */
int ima_match_policy(struct inode *inode, const struct cred *cred, u32 secid,
enum ima_hooks func, int mask, int flags, int *pcr,
- struct ima_template_desc **template_desc);
+ struct ima_template_desc **template_desc,
+ const char *keyring);
void ima_init_policy(void);
void ima_update_policy(void);
void ima_update_policy_flag(void);
* @func: caller identifier
* @pcr: pointer filled in if matched measure policy sets pcr=
* @template_desc: pointer filled in if matched measure policy sets template=
+ * @keyring: keyring name used to determine the action
*
* The policy is defined in terms of keypairs:
* subj=, obj=, type=, func=, mask=, fsmagic=
* subj,obj, and type: are LSM specific.
* func: FILE_CHECK | BPRM_CHECK | CREDS_CHECK | MMAP_CHECK | MODULE_CHECK
- * | KEXEC_CMDLINE
+ * | KEXEC_CMDLINE | KEY_CHECK
* mask: contains the permission mask
* fsmagic: hex value
*
*/
int ima_get_action(struct inode *inode, const struct cred *cred, u32 secid,
int mask, enum ima_hooks func, int *pcr,
- struct ima_template_desc **template_desc)
+ struct ima_template_desc **template_desc,
+ const char *keyring)
{
int flags = IMA_MEASURE | IMA_AUDIT | IMA_APPRAISE | IMA_HASH;
flags &= ima_policy_flag;
return ima_match_policy(inode, cred, secid, func, mask, flags, pcr,
- template_desc);
+ template_desc, keyring);
}
/*
security_task_getsecid(current, &secid);
return ima_match_policy(inode, current_cred(), secid, func, mask,
- IMA_APPRAISE | IMA_HASH, NULL, NULL);
+ IMA_APPRAISE | IMA_HASH, NULL, NULL, NULL);
}
static int ima_fix_xattr(struct dentry *dentry,
if ((rc == -EPERM) && (iint->flags & IMA_MEASURE))
process_buffer_measurement(digest, digestsize,
"blacklisted-hash", NONE,
- pcr);
+ pcr, NULL);
}
return rc;
* parameter to process_buffer_measurement() and is set
* in the "eventname" field in ima_event_data for
* the key measurement IMA event.
+ *
+ * The name of the keyring is also passed in the "keyring"
+ * parameter to process_buffer_measurement() to check
+ * if the IMA policy is configured to measure a key linked
+ * to the given keyring.
*/
process_buffer_measurement(payload, payload_len,
- keyring->description, KEY_CHECK, 0);
+ keyring->description, KEY_CHECK, 0,
+ keyring->description);
}
* Included is the appraise submask.
*/
action = ima_get_action(inode, cred, secid, mask, func, &pcr,
- &template_desc);
+ &template_desc, NULL);
violation_check = ((func == FILE_CHECK || func == MMAP_CHECK) &&
(ima_policy_flag & IMA_MEASURE));
if (!action && !violation_check)
* @eventname: event name to be used for the buffer entry.
* @func: IMA hook
* @pcr: pcr to extend the measurement
+ * @keyring: keyring name to determine the action to be performed
*
* Based on policy, the buffer is measured into the ima log.
*/
void process_buffer_measurement(const void *buf, int size,
const char *eventname, enum ima_hooks func,
- int pcr)
+ int pcr, const char *keyring)
{
int ret = 0;
struct ima_template_entry *entry = NULL;
if (func) {
security_task_getsecid(current, &secid);
action = ima_get_action(NULL, current_cred(), secid, 0, func,
- &pcr, &template);
+ &pcr, &template, keyring);
if (!(action & IMA_MEASURE))
return;
}
{
if (buf && size != 0)
process_buffer_measurement(buf, size, "kexec-cmdline",
- KEXEC_CMDLINE, 0);
+ KEXEC_CMDLINE, 0, NULL);
}
static int __init init_ima(void)
int type; /* audit type */
} lsm[MAX_LSM_RULES];
char *fsname;
+ char *keyrings; /* Measure keys added to these keyrings */
struct ima_template_desc *template;
};
return NOTIFY_OK;
}
+/**
+ * ima_match_keyring - determine whether the keyring matches the measure rule
+ * @rule: a pointer to a rule
+ * @keyring: name of the keyring to match against the measure rule
+ * @cred: a pointer to a credentials structure for user validation
+ *
+ * Returns true if keyring matches one in the rule, false otherwise.
+ */
+static bool ima_match_keyring(struct ima_rule_entry *rule,
+ const char *keyring, const struct cred *cred)
+{
+ char *keyrings, *next_keyring, *keyrings_ptr;
+ bool matched = false;
+
+ if ((rule->flags & IMA_UID) && !rule->uid_op(cred->uid, rule->uid))
+ return false;
+
+ if (!rule->keyrings)
+ return true;
+
+ if (!keyring)
+ return false;
+
+ keyrings = kstrdup(rule->keyrings, GFP_KERNEL);
+ if (!keyrings)
+ return false;
+
+ /*
+ * "keyrings=" is specified in the policy in the format below:
+ * keyrings=.builtin_trusted_keys|.ima|.evm
+ */
+ keyrings_ptr = keyrings;
+ while ((next_keyring = strsep(&keyrings_ptr, "|")) != NULL) {
+ if (!strcmp(next_keyring, keyring)) {
+ matched = true;
+ break;
+ }
+ }
+
+ kfree(keyrings);
+
+ return matched;
+}
+
/**
* ima_match_rules - determine whether an inode matches the measure rule.
* @rule: a pointer to a rule
* @secid: the secid of the task to be validated
* @func: LIM hook identifier
* @mask: requested action (MAY_READ | MAY_WRITE | MAY_APPEND | MAY_EXEC)
+ * @keyring: keyring name to check in policy for KEY_CHECK func
*
* Returns true on rule match, false on failure.
*/
static bool ima_match_rules(struct ima_rule_entry *rule, struct inode *inode,
const struct cred *cred, u32 secid,
- enum ima_hooks func, int mask)
+ enum ima_hooks func, int mask,
+ const char *keyring)
{
int i;
if ((func == KEXEC_CMDLINE) || (func == KEY_CHECK)) {
- if ((rule->flags & IMA_FUNC) && (rule->func == func))
+ if ((rule->flags & IMA_FUNC) && (rule->func == func)) {
+ if (func == KEY_CHECK)
+ return ima_match_keyring(rule, keyring, cred);
return true;
+ }
return false;
}
if ((rule->flags & IMA_FUNC) &&
* @mask: requested action (MAY_READ | MAY_WRITE | MAY_APPEND | MAY_EXEC)
* @pcr: set the pcr to extend
* @template_desc: the template that should be used for this rule
+ * @keyring: the keyring name, if given, to be used to check in the policy.
+ * keyring can be NULL if func is anything other than KEY_CHECK.
*
* Measure decision based on func/mask/fsmagic and LSM(subj/obj/type)
* conditions.
*/
int ima_match_policy(struct inode *inode, const struct cred *cred, u32 secid,
enum ima_hooks func, int mask, int flags, int *pcr,
- struct ima_template_desc **template_desc)
+ struct ima_template_desc **template_desc,
+ const char *keyring)
{
struct ima_rule_entry *entry;
int action = 0, actmask = flags | (flags << 1);
if (!(entry->action & actmask))
continue;
- if (!ima_match_rules(entry, inode, cred, secid, func, mask))
+ if (!ima_match_rules(entry, inode, cred, secid, func, mask,
+ keyring))
continue;
action |= entry->flags & IMA_ACTION_FLAGS;