--- /dev/null
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2021 Microsoft Corporation
+ *
+ * Author: Lakshmi Ramasubramanian (nramas@linux.microsoft.com)
+ *
+ * Measure critical data structures maintainted by SELinux
+ * using IMA subsystem.
+ */
+#include <linux/vmalloc.h>
+#include <linux/ima.h>
+#include "security.h"
+#include "ima.h"
+
+/*
+ * selinux_ima_measure_state - Measure hash of the SELinux policy
+ *
+ * @state: selinux state struct
+ *
+ * NOTE: This function must be called with policy_mutex held.
+ */
+void selinux_ima_measure_state(struct selinux_state *state)
+{
+ void *policy = NULL;
+ size_t policy_len;
+ int rc = 0;
+
+ /*
+ * Measure SELinux policy only after initialization is completed.
+ */
+ if (!selinux_initialized(state))
+ return;
+
+ rc = security_read_state_kernel(state, &policy, &policy_len);
+ if (rc) {
+ pr_err("SELinux: %s: failed to read policy %d.\n", __func__, rc);
+ return;
+ }
+
+ ima_measure_critical_data("selinux", "selinux-policy-hash",
+ policy, policy_len, true);
+
+ vfree(policy);
+}
#include "ebitmap.h"
#include "audit.h"
#include "policycap_names.h"
+#include "ima.h"
/* Forward declaration. */
static int context_struct_to_string(struct policydb *policydb,
selinux_status_update_policyload(state, seqno);
selinux_netlbl_cache_invalidate();
selinux_xfrm_notify_policyload();
+ selinux_ima_measure_state(state);
}
void selinux_policy_commit(struct selinux_state *state,
#endif /* CONFIG_NETLABEL */
/**
+ * __security_read_policy - read the policy.
+ * @policy: SELinux policy
+ * @data: binary policy data
+ * @len: length of data in bytes
+ *
+ */
+static int __security_read_policy(struct selinux_policy *policy,
+ void *data, size_t *len)
+{
+ int rc;
+ struct policy_file fp;
+
+ fp.data = data;
+ fp.len = *len;
+
+ rc = policydb_write(&policy->policydb, &fp);
+ if (rc)
+ return rc;
+
+ *len = (unsigned long)fp.data - (unsigned long)data;
+ return 0;
+}
+
+/**
* security_read_policy - read the policy.
+ * @state: selinux_state
* @data: binary policy data
* @len: length of data in bytes
*
void **data, size_t *len)
{
struct selinux_policy *policy;
- int rc;
- struct policy_file fp;
policy = rcu_dereference_protected(
state->policy, lockdep_is_held(&state->policy_mutex));
if (!*data)
return -ENOMEM;
- fp.data = *data;
- fp.len = *len;
+ return __security_read_policy(policy, *data, len);
+}
- rc = policydb_write(&policy->policydb, &fp);
- if (rc)
- return rc;
+/**
+ * security_read_state_kernel - read the policy.
+ * @state: selinux_state
+ * @data: binary policy data
+ * @len: length of data in bytes
+ *
+ * Allocates kernel memory for reading SELinux policy.
+ * This function is for internal use only and should not
+ * be used for returning data to user space.
+ *
+ * This function must be called with policy_mutex held.
+ */
+int security_read_state_kernel(struct selinux_state *state,
+ void **data, size_t *len)
+{
+ struct selinux_policy *policy;
- *len = (unsigned long)fp.data - (unsigned long)*data;
- return 0;
+ policy = rcu_dereference_protected(
+ state->policy, lockdep_is_held(&state->policy_mutex));
+ if (!policy)
+ return -EINVAL;
+
+ *len = policy->policydb.len;
+ *data = vmalloc(*len);
+ if (!*data)
+ return -ENOMEM;
+ return __security_read_policy(policy, *data, len);
}