releases/4.5.3/f2fs-crypto-handle-unexpected-lack-of-encryption-keys.patch

From ae1086686487f13130937918ca91d920c1daafcb Mon Sep 17 00:00:00 2001
From: Chao Yu <chao2.yu@samsung.com>
Date: Sun, 14 Feb 2016 18:58:35 +0800
Subject: f2fs crypto: handle unexpected lack of encryption keys

From: Chao Yu <chao2.yu@samsung.com>

commit ae1086686487f13130937918ca91d920c1daafcb upstream.

This patch syncs f2fs with commit abdd438b26b4 ("ext4 crypto: handle
unexpected lack of encryption keys") from ext4.

Fix up attempts by users to try to write to a file when they don't
have access to the encryption key.

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 fs/f2fs/crypto_policy.c |    3 ++-
 fs/f2fs/file.c          |    6 +++++-
 2 files changed, 7 insertions(+), 2 deletions(-)

--- a/fs/f2fs/crypto_policy.c
+++ b/fs/f2fs/crypto_policy.c
@@ -192,7 +192,8 @@ int f2fs_inherit_context(struct inode *p
 		return res;
 
 	ci = F2FS_I(parent)->i_crypt_info;
-	BUG_ON(ci == NULL);
+	if (ci == NULL)
+		return -ENOKEY;
 
 	ctx.format = F2FS_ENCRYPTION_CONTEXT_FORMAT_V1;
 
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -425,6 +425,8 @@ static int f2fs_file_mmap(struct file *f
 		err = f2fs_get_encryption_info(inode);
 		if (err)
 			return 0;
+		if (!f2fs_encrypted_inode(inode))
+			return -ENOKEY;
 	}
 
 	/* we don't need to use inline_data strictly */
@@ -444,7 +446,9 @@ static int f2fs_file_open(struct inode *
 	if (!ret && f2fs_encrypted_inode(inode)) {
 		ret = f2fs_get_encryption_info(inode);
 		if (ret)
-			ret = -EACCES;
+			return -EACCES;
+		if (!f2fs_encrypted_inode(inode))
+			return -ENOKEY;
 	}
 	return ret;
 }