ext4 crypto: teach ext4_htree_store_dirent() to store decrypted filenames

For encrypted directories, we need to pass in a separate parameter for
the decrypted filename, since the directory entry contains the
encrypted filename.

Signed-off-by: Theodore Ts'o <tytso@mit.edu>

fs/ext4/dir.c

@@ -382,10 +382,15 @@ void ext4_htree_free_dir_info(struct dir_private_info *p)
 
 /*
  * Given a directory entry, enter it into the fname rb tree.
+ *
+ * When filename encryption is enabled, the dirent will hold the
+ * encrypted filename, while the htree will hold decrypted filename.
+ * The decrypted filename is passed in via ent_name.  parameter.
  */
 int ext4_htree_store_dirent(struct file *dir_file, __u32 hash,
 			     __u32 minor_hash,
-			     struct ext4_dir_entry_2 *dirent)
+			    struct ext4_dir_entry_2 *dirent,
+			    struct ext4_str *ent_name)
 {
 	struct rb_node **p, *parent = NULL;
 	struct fname *fname, *new_fn;
@@ -396,17 +401,17 @@ int ext4_htree_store_dirent(struct file *dir_file, __u32 hash,
 	p = &info->root.rb_node;
 
 	/* Create and allocate the fname structure */
-	len = sizeof(struct fname) + dirent->name_len + 1;
+	len = sizeof(struct fname) + ent_name->len + 1;
 	new_fn = kzalloc(len, GFP_KERNEL);
 	if (!new_fn)
 		return -ENOMEM;
 	new_fn->hash = hash;
 	new_fn->minor_hash = minor_hash;
 	new_fn->inode = le32_to_cpu(dirent->inode);
-	new_fn->name_len = dirent->name_len;
+	new_fn->name_len = ent_name->len;
 	new_fn->file_type = dirent->file_type;
-	memcpy(new_fn->name, dirent->name, dirent->name_len);
-	new_fn->name[dirent->name_len] = 0;
+	memcpy(new_fn->name, ent_name->name, ent_name->len);
+	new_fn->name[ent_name->len] = 0;
 
 	while (*p) {
 		parent = *p;

fs/ext4/ext4.h

@@ -2142,8 +2142,9 @@ extern int __ext4_check_dir_entry(const char *, unsigned int, struct inode *,
 	unlikely(__ext4_check_dir_entry(__func__, __LINE__, (dir), (filp), \
 					(de), (bh), (buf), (size), (offset)))
 extern int ext4_htree_store_dirent(struct file *dir_file, __u32 hash,
-				    __u32 minor_hash,
-				    struct ext4_dir_entry_2 *dirent);
+				__u32 minor_hash,
+				struct ext4_dir_entry_2 *dirent,
+				struct ext4_str *ent_name);
 extern void ext4_htree_free_dir_info(struct dir_private_info *p);
 extern int ext4_find_dest_de(struct inode *dir, struct inode *inode,
 			     struct buffer_head *bh,

fs/ext4/inline.c

@@ -1327,6 +1327,7 @@ int htree_inlinedir_to_tree(struct file *dir_file,
 	struct ext4_iloc iloc;
 	void *dir_buf = NULL;
 	struct ext4_dir_entry_2 fake;
+	struct ext4_str tmp_str;
 
 	ret = ext4_get_inode_loc(inode, &iloc);
 	if (ret)
@@ -1398,8 +1399,10 @@ int htree_inlinedir_to_tree(struct file *dir_file,
 			continue;
 		if (de->inode == 0)
 			continue;
-		err = ext4_htree_store_dirent(dir_file,
-				   hinfo->hash, hinfo->minor_hash, de);
+		tmp_str.name = de->name;
+		tmp_str.len = de->name_len;
+		err = ext4_htree_store_dirent(dir_file, hinfo->hash,
+					      hinfo->minor_hash, de, &tmp_str);
 		if (err) {
 			count = err;
 			goto out;

fs/ext4/namei.c

@@ -877,6 +877,7 @@ static int htree_dirblock_to_tree(struct file *dir_file,
 	struct buffer_head *bh;
 	struct ext4_dir_entry_2 *de, *top;
 	int err = 0, count = 0;
+	struct ext4_str tmp_str;
 
 	dxtrace(printk(KERN_INFO "In htree dirblock_to_tree: block %lu\n",
 							(unsigned long)block));
@@ -903,8 +904,11 @@ static int htree_dirblock_to_tree(struct file *dir_file,
 			continue;
 		if (de->inode == 0)
 			continue;
-		if ((err = ext4_htree_store_dirent(dir_file,
-				   hinfo->hash, hinfo->minor_hash, de)) != 0) {
+		tmp_str.name = de->name;
+		tmp_str.len = de->name_len;
+		err = ext4_htree_store_dirent(dir_file,
+			   hinfo->hash, hinfo->minor_hash, de, &tmp_str);
+		if (err != 0) {
 			brelse(bh);
 			return err;
 		}
@@ -934,6 +938,7 @@ int ext4_htree_fill_tree(struct file *dir_file, __u32 start_hash,
 	int count = 0;
 	int ret, err;
 	__u32 hashval;
+	struct ext4_str tmp_str;
 
 	dxtrace(printk(KERN_DEBUG "In htree_fill_tree, start hash: %x:%x\n",
 		       start_hash, start_minor_hash));
@@ -969,14 +974,22 @@ int ext4_htree_fill_tree(struct file *dir_file, __u32 start_hash,
 	/* Add '.' and '..' from the htree header */
 	if (!start_hash && !start_minor_hash) {
 		de = (struct ext4_dir_entry_2 *) frames[0].bh->b_data;
-		if ((err = ext4_htree_store_dirent(dir_file, 0, 0, de)) != 0)
+		tmp_str.name = de->name;
+		tmp_str.len = de->name_len;
+		err = ext4_htree_store_dirent(dir_file, 0, 0,
+					      de, &tmp_str);
+		if (err != 0)
 			goto errout;
 		count++;
 	}
 	if (start_hash < 2 || (start_hash ==2 && start_minor_hash==0)) {
 		de = (struct ext4_dir_entry_2 *) frames[0].bh->b_data;
 		de = ext4_next_entry(de, dir->i_sb->s_blocksize);
-		if ((err = ext4_htree_store_dirent(dir_file, 2, 0, de)) != 0)
+		tmp_str.name = de->name;
+		tmp_str.len = de->name_len;
+		err = ext4_htree_store_dirent(dir_file, 2, 0,
+					      de, &tmp_str);
+		if (err != 0)
 			goto errout;
 		count++;
 	}