Merge tag 'fscrypt-for-linus' of git://git.kernel.org/pub/scm/fs/fscrypt/linux

Pull fscrypt updates from Eric Biggers:
 "Simplify the implementation of the test_dummy_encryption mount option
  by adding the 'test dummy key' on-demand"

* tag 'fscrypt-for-linus' of git://git.kernel.org/pub/scm/fs/fscrypt/linux:
  fscrypt: clean up fscrypt_add_test_dummy_key()
  fs/super.c: stop calling fscrypt_destroy_keyring() from __put_super()
  f2fs: stop calling fscrypt_add_test_dummy_key()
  ext4: stop calling fscrypt_add_test_dummy_key()
  fscrypt: add the test dummy encryption key on-demand

1 files changed, 21 insertions, 2 deletions

diff --git a/fs/crypto/keysetup.c b/fs/crypto/keysetup.c
index 94757ccd3056..aa94fba9d17e 100644
--- a/fs/crypto/keysetup.c
+++ b/fs/crypto/keysetup.c
@@ -438,6 +438,7 @@ static int setup_file_encryption_key(struct fscrypt_info *ci,
 				     bool need_dirhash_key,
 				     struct fscrypt_master_key **mk_ret)
 {
+	struct super_block *sb = ci->ci_inode->i_sb;
 	struct fscrypt_key_specifier mk_spec;
 	struct fscrypt_master_key *mk;
 	int err;
@@ -450,8 +451,26 @@ static int setup_file_encryption_key(struct fscrypt_info *ci,
 	if (err)
 		return err;
 
-	mk = fscrypt_find_master_key(ci->ci_inode->i_sb, &mk_spec);
-	if (!mk) {
+	mk = fscrypt_find_master_key(sb, &mk_spec);
+	if (unlikely(!mk)) {
+		const union fscrypt_policy *dummy_policy =
+			fscrypt_get_dummy_policy(sb);
+
+		/*
+		 * Add the test_dummy_encryption key on-demand.  In principle,
+		 * it should be added at mount time.  Do it here instead so that
+		 * the individual filesystems don't need to worry about adding
+		 * this key at mount time and cleaning up on mount failure.
+		 */
+		if (dummy_policy &&
+		    fscrypt_policies_equal(dummy_policy, &ci->ci_policy)) {
+			err = fscrypt_add_test_dummy_key(sb, &mk_spec);
+			if (err)
+				return err;
+			mk = fscrypt_find_master_key(sb, &mk_spec);
+		}
+	}
+	if (unlikely(!mk)) {
 		if (ci->ci_policy.version != FSCRYPT_POLICY_V1)
 			return -ENOKEY;