Patch "fscrypt: use ENOKEY when file cannot be created w/o key" has been added to the 4.9-stable tree

This is a note to let you know that I've just added the patch titled

fscrypt: use ENOKEY when file cannot be created w/o key

to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
fscrypt-use-enokey-when-file-cannot-be-created-w-o-key.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Eric Biggers <[email protected]>
Date: Mon, 5 Dec 2016 11:12:44 -0800
Subject: fscrypt: use ENOKEY when file cannot be created w/o key

From: Eric Biggers <[email protected]>

[ Upstream commit 54475f531bb8d7078f63c159e5e0615d486c498c ]

As part of an effort to clean up fscrypt-related error codes, make attempting to create a file in an encrypted directory that hasn't been "unlocked" fail with ENOKEY. Previously, several error codes were used for this case, including ENOENT, EACCES, and EPERM, and they were not consistent between and within filesystems. ENOKEY is a better choice because it expresses that the failure is due to lacking the encryption key. It also matches the error code returned when trying to open an encrypted regular file without the key.

I am not aware of any users who might be relying on the previous inconsistent error codes, which were never documented anywhere.

This failure case will be exercised by an xfstest.

---
 fs/crypto/fname.c |    4 ++--
 fs/ext4/ialloc.c  |    2 +-
 fs/ext4/namei.c   |    4 +++-
 fs/f2fs/dir.c     |    5 ++++-
 fs/f2fs/namei.c   |    4 ++--
 5 files changed, 12 insertions(+), 7 deletions(-)

@@ -332,7 +332,7 @@ int fscrypt_fname_usr_to_disk(struct ino
 	 * in a directory. Consequently, a user space name cannot be mapped to
 	 * a disk-space name
 	 */
-	return -EACCES;
+	return -ENOKEY;
 }
 EXPORT_SYMBOL(fscrypt_fname_usr_to_disk);
 

@@ -367,7 +367,7 @@ int fscrypt_setup_filename(struct inode
 		return 0;
 	}
 	if (!lookup)
-		return -EACCES;
+		return -ENOKEY;
 
 	/*
 	 * We don't have the key and we are doing a lookup; decode the

@@ -771,7 +771,7 @@ struct inode *__ext4_new_inode(handle_t
 		if (err)
 			return ERR_PTR(err);
 		if (!fscrypt_has_encryption_key(dir))
-			return ERR_PTR(-EPERM);
+			return ERR_PTR(-ENOKEY);
 		if (!handle)
 			nblocks += EXT4_DATA_TRANS_BLOCKS(dir->i_sb);
 		encrypt = 1;

@@ -1378,6 +1378,8 @@ static struct buffer_head * ext4_find_en
 		return NULL;
 
 	retval = ext4_fname_setup_filename(dir, d_name, 1, &fname);
+	if (retval == -ENOENT)
+		return NULL;
 	if (retval)
 		return ERR_PTR(retval);
 

@@ -3090,7 +3092,7 @@ static int ext4_symlink(struct inode *di
 		if (err)
 			return err;
 		if (!fscrypt_has_encryption_key(dir))
-			return -EPERM;
+			return -ENOKEY;
 		disk_link.len = (fscrypt_fname_encrypted_size(dir, len) +
 				 sizeof(struct fscrypt_symlink_data));
 		sd = kzalloc(disk_link.len, GFP_KERNEL);

@@ -277,7 +277,10 @@ struct f2fs_dir_entry *f2fs_find_entry(s
 
 	err = fscrypt_setup_filename(dir, child, 1, &fname);
 	if (err) {
-		*res_page = ERR_PTR(err);
+		if (err == -ENOENT)
+			*res_page = NULL;
+		else
+			*res_page = ERR_PTR(err);
 		return NULL;
 	}
 

@@ -403,7 +403,7 @@ static int f2fs_symlink(struct inode *di
 			return err;
 
 		if (!fscrypt_has_encryption_key(dir))
-			return -EPERM;
+			return -ENOKEY;
 
 		disk_link.len = (fscrypt_fname_encrypted_size(dir, len) +
 				sizeof(struct fscrypt_symlink_data));

@@ -447,7 +447,7 @@ static int f2fs_symlink(struct inode *di
 			goto err_out;
 
 		if (!fscrypt_has_encryption_key(inode)) {
-			err = -EPERM;
+			err = -ENOKEY;
 			goto err_out;
 		}
 

Patches currently in stable-queue which might be from [email protected] are

queue-4.9/fscrypt-use-enotdir-when-setting-encryption-policy-on-nondirectory.patch queue-4.9/lib-mpi-call-cond_resched-from-mpi_powm-loop.patch queue-4.9/fscrypt-use-enokey-when-file-cannot-be-created-w-o-key.patch queue-4.9/fscrypt-lock-mutex-before-checking-for-bounce-page-pool.patch queue-4.9/dm-bufio-fix-integer-overflow-when-limiting-maximum-cache-size.patch queue-4.9/libceph-don-t-warn-if-user-tries-to-add-invalid-key.patch