[PATCH 7/7] f2fs crypto: handle unexpected lack of encryption keys

[Chao Yu]

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 <ty...@mit.edu>
Signed-off-by: Chao Yu <chao2...@samsung.com>
---
 fs/f2fs/crypto_policy.c | 3 ++-
 fs/f2fs/file.c          | 6 +++++-
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/fs/f2fs/crypto_policy.c b/fs/f2fs/crypto_policy.c
index 0fb08b0..4d7d7ff 100644
--- a/fs/f2fs/crypto_policy.c
+++ b/fs/f2fs/crypto_policy.c
@@ -192,7 +192,8 @@ int f2fs_inherit_context(struct inode *parent, struct inode 
*child,
                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;
 
diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index 05f5f2f..8dea195 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -424,6 +424,8 @@ static int f2fs_file_mmap(struct file *file, struct 
vm_area_struct *vma)
                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 */
@@ -443,7 +445,9 @@ static int f2fs_file_open(struct inode *inode, struct file 
*filp)
        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;
 }
-- 
2.7.0.2.g1b0b6dd