1 files changed, 113 insertions, 26 deletions

diff --git a/certs/system_keyring.c b/certs/system_keyring.c
index f4180326c..50979d6dc 100644
--- a/certs/system_keyring.c
+++ b/certs/system_keyring.c
@@ -18,29 +18,88 @@
 #include <keys/system_keyring.h>
 #include <crypto/pkcs7.h>
 
-struct key *system_trusted_keyring;
-EXPORT_SYMBOL_GPL(system_trusted_keyring);
+static struct key *builtin_trusted_keys;
+#ifdef CONFIG_SECONDARY_TRUSTED_KEYRING
+static struct key *secondary_trusted_keys;
+#endif
 
 extern __initconst const u8 system_certificate_list[];
 extern __initconst const unsigned long system_certificate_list_size;
 
+/**
+ * restrict_link_to_builtin_trusted - Restrict keyring addition by built in CA
+ *
+ * Restrict the addition of keys into a keyring based on the key-to-be-added
+ * being vouched for by a key in the built in system keyring.
+ */
+int restrict_link_by_builtin_trusted(struct key *keyring,
+				     const struct key_type *type,
+				     const union key_payload *payload)
+{
+	return restrict_link_by_signature(builtin_trusted_keys, type, payload);
+}
+
+#ifdef CONFIG_SECONDARY_TRUSTED_KEYRING
+/**
+ * restrict_link_by_builtin_and_secondary_trusted - Restrict keyring
+ *   addition by both builtin and secondary keyrings
+ *
+ * Restrict the addition of keys into a keyring based on the key-to-be-added
+ * being vouched for by a key in either the built-in or the secondary system
+ * keyrings.
+ */
+int restrict_link_by_builtin_and_secondary_trusted(
+	struct key *keyring,
+	const struct key_type *type,
+	const union key_payload *payload)
+{
+	/* If we have a secondary trusted keyring, then that contains a link
+	 * through to the builtin keyring and the search will follow that link.
+	 */
+	if (type == &key_type_keyring &&
+	    keyring == secondary_trusted_keys &&
+	    payload == &builtin_trusted_keys->payload)
+		/* Allow the builtin keyring to be added to the secondary */
+		return 0;
+
+	return restrict_link_by_signature(secondary_trusted_keys, type, payload);
+}
+#endif
+
 /*
- * Load the compiled-in keys
+ * Create the trusted keyrings
  */
 static __init int system_trusted_keyring_init(void)
 {
-	pr_notice("Initialise system trusted keyring\n");
+	pr_notice("Initialise system trusted keyrings\n");
 
-	system_trusted_keyring =
-		keyring_alloc(".system_keyring",
+	builtin_trusted_keys =
+		keyring_alloc(".builtin_trusted_keys",
 			      KUIDT_INIT(0), KGIDT_INIT(0), current_cred(),
 			      ((KEY_POS_ALL & ~KEY_POS_SETATTR) |
 			      KEY_USR_VIEW | KEY_USR_READ | KEY_USR_SEARCH),
-			      KEY_ALLOC_NOT_IN_QUOTA, NULL);
-	if (IS_ERR(system_trusted_keyring))
-		panic("Can't allocate system trusted keyring\n");
+			      KEY_ALLOC_NOT_IN_QUOTA,
+			      NULL, NULL);
+	if (IS_ERR(builtin_trusted_keys))
+		panic("Can't allocate builtin trusted keyring\n");
+
+#ifdef CONFIG_SECONDARY_TRUSTED_KEYRING
+	secondary_trusted_keys =
+		keyring_alloc(".secondary_trusted_keys",
+			      KUIDT_INIT(0), KGIDT_INIT(0), current_cred(),
+			      ((KEY_POS_ALL & ~KEY_POS_SETATTR) |
+			       KEY_USR_VIEW | KEY_USR_READ | KEY_USR_SEARCH |
+			       KEY_USR_WRITE),
+			      KEY_ALLOC_NOT_IN_QUOTA,
+			      restrict_link_by_builtin_and_secondary_trusted,
+			      NULL);
+	if (IS_ERR(secondary_trusted_keys))
+		panic("Can't allocate secondary trusted keyring\n");
+
+	if (key_link(secondary_trusted_keys, builtin_trusted_keys) < 0)
+		panic("Can't link trusted keyrings\n");
+#endif
 
-	set_bit(KEY_FLAG_TRUSTED_ONLY, &system_trusted_keyring->flags);
 	return 0;
 }
 
@@ -76,7 +135,7 @@ static __init int load_system_certificate_list(void)
 		if (plen > end - p)
 			goto dodgy_cert;
 
-		key = key_create_or_update(make_key_ref(system_trusted_keyring, 1),
+		key = key_create_or_update(make_key_ref(builtin_trusted_keys, 1),
 					   "asymmetric",
 					   NULL,
 					   p,
@@ -84,8 +143,8 @@ static __init int load_system_certificate_list(void)
 					   ((KEY_POS_ALL & ~KEY_POS_SETATTR) |
 					   KEY_USR_VIEW | KEY_USR_READ),
 					   KEY_ALLOC_NOT_IN_QUOTA |
-					   KEY_ALLOC_TRUSTED |
-					   KEY_ALLOC_BUILT_IN);
+					   KEY_ALLOC_BUILT_IN |
+					   KEY_ALLOC_BYPASS_RESTRICTION);
 		if (IS_ERR(key)) {
 			pr_err("Problem loading in-kernel X.509 certificate (%ld)\n",
 			       PTR_ERR(key));
@@ -108,19 +167,27 @@ late_initcall(load_system_certificate_list);
 #ifdef CONFIG_SYSTEM_DATA_VERIFICATION
 
 /**
- * Verify a PKCS#7-based signature on system data.
- * @data: The data to be verified.
+ * verify_pkcs7_signature - Verify a PKCS#7-based signature on system data.
+ * @data: The data to be verified (NULL if expecting internal data).
  * @len: Size of @data.
  * @raw_pkcs7: The PKCS#7 message that is the signature.
  * @pkcs7_len: The size of @raw_pkcs7.
+ * @trusted_keys: Trusted keys to use (NULL for builtin trusted keys only,
+ *					(void *)1UL for all trusted keys).
  * @usage: The use to which the key is being put.
+ * @view_content: Callback to gain access to content.
+ * @ctx: Context for callback.
  */
-int system_verify_data(const void *data, unsigned long len,
-		       const void *raw_pkcs7, size_t pkcs7_len,
-		       enum key_being_used_for usage)
+int verify_pkcs7_signature(const void *data, size_t len,
+			   const void *raw_pkcs7, size_t pkcs7_len,
+			   struct key *trusted_keys,
+			   enum key_being_used_for usage,
+			   int (*view_content)(void *ctx,
+					       const void *data, size_t len,
+					       size_t asn1hdrlen),
+			   void *ctx)
 {
 	struct pkcs7_message *pkcs7;
-	bool trusted;
 	int ret;
 
 	pkcs7 = pkcs7_parse_message(raw_pkcs7, pkcs7_len);
@@ -128,7 +195,7 @@ int system_verify_data(const void *data, unsigned long len,
 		return PTR_ERR(pkcs7);
 
 	/* The data should be detached - so we need to supply it. */
-	if (pkcs7_supply_detached_data(pkcs7, data, len) < 0) {
+	if (data && pkcs7_supply_detached_data(pkcs7, data, len) < 0) {
 		pr_err("PKCS#7 signature with non-detached data\n");
 		ret = -EBADMSG;
 		goto error;
@@ -138,13 +205,33 @@ int system_verify_data(const void *data, unsigned long len,
 	if (ret < 0)
 		goto error;
 
-	ret = pkcs7_validate_trust(pkcs7, system_trusted_keyring, &trusted);
-	if (ret < 0)
+	if (!trusted_keys) {
+		trusted_keys = builtin_trusted_keys;
+	} else if (trusted_keys == (void *)1UL) {
+#ifdef CONFIG_SECONDARY_TRUSTED_KEYRING
+		trusted_keys = secondary_trusted_keys;
+#else
+		trusted_keys = builtin_trusted_keys;
+#endif
+	}
+	ret = pkcs7_validate_trust(pkcs7, trusted_keys);
+	if (ret < 0) {
+		if (ret == -ENOKEY)
+			pr_err("PKCS#7 signature not signed with a trusted key\n");
 		goto error;
+	}
+
+	if (view_content) {
+		size_t asn1hdrlen;
+
+		ret = pkcs7_get_content_data(pkcs7, &data, &len, &asn1hdrlen);
+		if (ret < 0) {
+			if (ret == -ENODATA)
+				pr_devel("PKCS#7 message does not contain data\n");
+			goto error;
+		}
 
-	if (!trusted) {
-		pr_err("PKCS#7 signature not signed with a trusted key\n");
-		ret = -ENOKEY;
+		ret = view_content(ctx, data, len, asn1hdrlen);
 	}
 
 error:
@@ -152,6 +239,6 @@ error:
 	pr_devel("<==%s() = %d\n", __func__, ret);
 	return ret;
 }
-EXPORT_SYMBOL_GPL(system_verify_data);
+EXPORT_SYMBOL_GPL(verify_pkcs7_signature);
 
 #endif /* CONFIG_SYSTEM_DATA_VERIFICATION */