Merge tag 'asoc-fix-v4.15-rc4' of https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound into for-linus

ASoC: Fixes for v4.15

This is a fairly large set of fixes, they've been delayed partly as more
and more keep coming in.  Most of them are very small driver specific
fixes, the biggest individual thing is the revert of the rcar IOMMU
support - it was causing problems and there wasn't the confidence that
it could be resolved sensibly.  There's also a relatively large change
in the Freescale SSI controller which resolves some issues with the
AC'97 mode, these aren't that large in the grand scheme of things and
reflect some fairly thorough review and testing.

1 files changed, 37 insertions, 11 deletions

diff --git a/security/keys/request_key.c b/security/keys/request_key.c
index e8036cd0ad54..114f7408feee 100644
--- a/security/keys/request_key.c
+++ b/security/keys/request_key.c
@@ -251,11 +251,12 @@ static int construct_key(struct key *key, const void *callout_info,
  * The keyring selected is returned with an extra reference upon it which the
  * caller must release.
  */
-static void construct_get_dest_keyring(struct key **_dest_keyring)
+static int construct_get_dest_keyring(struct key **_dest_keyring)
 {
 	struct request_key_auth *rka;
 	const struct cred *cred = current_cred();
 	struct key *dest_keyring = *_dest_keyring, *authkey;
+	int ret;
 
 	kenter("%p", dest_keyring);
 
@@ -264,6 +265,8 @@ static void construct_get_dest_keyring(struct key **_dest_keyring)
 		/* the caller supplied one */
 		key_get(dest_keyring);
 	} else {
+		bool do_perm_check = true;
+
 		/* use a default keyring; falling through the cases until we
 		 * find one that we actually have */
 		switch (cred->jit_keyring) {
@@ -278,8 +281,10 @@ static void construct_get_dest_keyring(struct key **_dest_keyring)
 					dest_keyring =
 						key_get(rka->dest_keyring);
 				up_read(&authkey->sem);
-				if (dest_keyring)
+				if (dest_keyring) {
+					do_perm_check = false;
 					break;
+				}
 			}
 
 		case KEY_REQKEY_DEFL_THREAD_KEYRING:
@@ -314,11 +319,29 @@ static void construct_get_dest_keyring(struct key **_dest_keyring)
 		default:
 			BUG();
 		}
+
+		/*
+		 * Require Write permission on the keyring.  This is essential
+		 * because the default keyring may be the session keyring, and
+		 * joining a keyring only requires Search permission.
+		 *
+		 * However, this check is skipped for the "requestor keyring" so
+		 * that /sbin/request-key can itself use request_key() to add
+		 * keys to the original requestor's destination keyring.
+		 */
+		if (dest_keyring && do_perm_check) {
+			ret = key_permission(make_key_ref(dest_keyring, 1),
+					     KEY_NEED_WRITE);
+			if (ret) {
+				key_put(dest_keyring);
+				return ret;
+			}
+		}
 	}
 
 	*_dest_keyring = dest_keyring;
 	kleave(" [dk %d]", key_serial(dest_keyring));
-	return;
+	return 0;
 }
 
 /*
@@ -444,11 +467,15 @@ static struct key *construct_key_and_link(struct keyring_search_context *ctx,
 	if (ctx->index_key.type == &key_type_keyring)
 		return ERR_PTR(-EPERM);
 
-	user = key_user_lookup(current_fsuid());
-	if (!user)
-		return ERR_PTR(-ENOMEM);
+	ret = construct_get_dest_keyring(&dest_keyring);
+	if (ret)
+		goto error;
 
-	construct_get_dest_keyring(&dest_keyring);
+	user = key_user_lookup(current_fsuid());
+	if (!user) {
+		ret = -ENOMEM;
+		goto error_put_dest_keyring;
+	}
 
 	ret = construct_alloc_key(ctx, dest_keyring, flags, user, &key);
 	key_user_put(user);
@@ -463,7 +490,7 @@ static struct key *construct_key_and_link(struct keyring_search_context *ctx,
 	} else if (ret == -EINPROGRESS) {
 		ret = 0;
 	} else {
-		goto couldnt_alloc_key;
+		goto error_put_dest_keyring;
 	}
 
 	key_put(dest_keyring);
@@ -473,8 +500,9 @@ static struct key *construct_key_and_link(struct keyring_search_context *ctx,
 construction_failed:
 	key_negate_and_link(key, key_negative_timeout, NULL, NULL);
 	key_put(key);
-couldnt_alloc_key:
+error_put_dest_keyring:
 	key_put(dest_keyring);
+error:
 	kleave(" = %d", ret);
 	return ERR_PTR(ret);
 }
@@ -546,9 +574,7 @@ struct key *request_key_and_link(struct key_type *type,
 	if (!IS_ERR(key_ref)) {
 		key = key_ref_to_ptr(key_ref);
 		if (dest_keyring) {
-			construct_get_dest_keyring(&dest_keyring);
 			ret = key_link(dest_keyring, key);
-			key_put(dest_keyring);
 			if (ret < 0) {
 				key_put(key);
 				key = ERR_PTR(ret);