f2fs crypto: handle unexpected lack of encryption keys

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>

2 files changed, 7 insertions, 2 deletions

diff --git a/fs/f2fs/crypto_policy.c b/fs/f2fs/crypto_policy.c
index d4a96af513c2..596f02490f27 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 05f5f2f8f8fd..8dea19500120 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;
 }