ext4 crypto: migrate into vfs's crypto engine

This patch removes the most parts of internal crypto codes.
And then, it modifies and adds some ext4-specific crypt codes to use the generic
facility.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

1 files changed, 63 insertions, 68 deletions

diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index 94d22e78a7dd..4637c439ca54 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -611,19 +611,19 @@ static struct stats dx_show_leaf(struct inode *dir,
 #ifdef CONFIG_EXT4_FS_ENCRYPTION
 				int len;
 				char *name;
-				struct ext4_str fname_crypto_str
-					= {.name = NULL, .len = 0};
+				struct fscrypt_str fname_crypto_str =
+					FSTR_INIT(NULL, 0);
 				int res = 0;
 
 				name  = de->name;
 				len = de->name_len;
-				if (ext4_encrypted_inode(inode))
-					res = ext4_get_encryption_info(dir);
+				if (ext4_encrypted_inode(dir))
+					res = fscrypt_get_encryption_info(dir);
 				if (res) {
 					printk(KERN_WARNING "Error setting up"
 					       " fname crypto: %d\n", res);
 				}
-				if (ctx == NULL) {
+				if (!fscrypt_has_encryption_key(dir)) {
 					/* Directory is not encrypted */
 					ext4fs_dirhash(de->name,
 						de->name_len, &h);
@@ -632,19 +632,21 @@ static struct stats dx_show_leaf(struct inode *dir,
 					       (unsigned) ((char *) de
 							   - base));
 				} else {
+					struct fscrypt_str de_name =
+						FSTR_INIT(name, len);
+
 					/* Directory is encrypted */
-					res = ext4_fname_crypto_alloc_buffer(
-						ctx, de->name_len,
+					res = fscrypt_fname_alloc_buffer(
+						dir, len,
 						&fname_crypto_str);
-					if (res < 0) {
+					if (res < 0)
 						printk(KERN_WARNING "Error "
 							"allocating crypto "
 							"buffer--skipping "
 							"crypto\n");
-						ctx = NULL;
-					}
-					res = ext4_fname_disk_to_usr(ctx, NULL, de,
-							&fname_crypto_str);
+					res = fscrypt_fname_disk_to_usr(dir,
+						0, 0, &de_name,
+						&fname_crypto_str);
 					if (res < 0) {
 						printk(KERN_WARNING "Error "
 							"converting filename "
@@ -661,8 +663,8 @@ static struct stats dx_show_leaf(struct inode *dir,
 					printk("%*.s:(E)%x.%u ", len, name,
 					       h.hash, (unsigned) ((char *) de
 								   - base));
-					ext4_fname_crypto_free_buffer(
-						&fname_crypto_str);
+					fscrypt_fname_free_buffer(
+							&fname_crypto_str);
 				}
 #else
 				int len = de->name_len;
@@ -951,7 +953,7 @@ 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 fname_crypto_str = {.name = NULL, .len = 0}, tmp_str;
+	struct fscrypt_str fname_crypto_str = FSTR_INIT(NULL, 0), tmp_str;
 
 	dxtrace(printk(KERN_INFO "In htree dirblock_to_tree: block %lu\n",
 							(unsigned long)block));
@@ -966,12 +968,12 @@ static int htree_dirblock_to_tree(struct file *dir_file,
 #ifdef CONFIG_EXT4_FS_ENCRYPTION
 	/* Check if the directory is encrypted */
 	if (ext4_encrypted_inode(dir)) {
-		err = ext4_get_encryption_info(dir);
+		err = fscrypt_get_encryption_info(dir);
 		if (err < 0) {
 			brelse(bh);
 			return err;
 		}
-		err = ext4_fname_crypto_alloc_buffer(dir, EXT4_NAME_LEN,
+		err = fscrypt_fname_alloc_buffer(dir, EXT4_NAME_LEN,
 						     &fname_crypto_str);
 		if (err < 0) {
 			brelse(bh);
@@ -1002,10 +1004,13 @@ static int htree_dirblock_to_tree(struct file *dir_file,
 				   &tmp_str);
 		} else {
 			int save_len = fname_crypto_str.len;
+			struct fscrypt_str de_name = FSTR_INIT(de->name,
+								de->name_len);
 
 			/* Directory is encrypted */
-			err = ext4_fname_disk_to_usr(dir, hinfo, de,
-						     &fname_crypto_str);
+			err = fscrypt_fname_disk_to_usr(dir, hinfo->hash,
+					hinfo->minor_hash, &de_name,
+					&fname_crypto_str);
 			if (err < 0) {
 				count = err;
 				goto errout;
@@ -1024,7 +1029,7 @@ static int htree_dirblock_to_tree(struct file *dir_file,
 errout:
 	brelse(bh);
 #ifdef CONFIG_EXT4_FS_ENCRYPTION
-	ext4_fname_crypto_free_buffer(&fname_crypto_str);
+	fscrypt_fname_free_buffer(&fname_crypto_str);
 #endif
 	return count;
 }
@@ -1049,7 +1054,7 @@ 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;
+	struct fscrypt_str tmp_str;
 
 	dxtrace(printk(KERN_DEBUG "In htree_fill_tree, start hash: %x:%x\n",
 		       start_hash, start_minor_hash));
@@ -1562,26 +1567,23 @@ static struct dentry *ext4_lookup(struct inode *dir, struct dentry *dentry, unsi
 	struct ext4_dir_entry_2 *de;
 	struct buffer_head *bh;
 
-       if (ext4_encrypted_inode(dir)) {
-               int res = ext4_get_encryption_info(dir);
+	if (ext4_encrypted_inode(dir)) {
+		int res = fscrypt_get_encryption_info(dir);
 
 		/*
-		 * This should be a properly defined flag for
-		 * dentry->d_flags when we uplift this to the VFS.
-		 * d_fsdata is set to (void *) 1 if if the dentry is
+		 * DCACHE_ENCRYPTED_WITH_KEY is set if the dentry is
 		 * created while the directory was encrypted and we
-		 * don't have access to the key.
+		 * have access to the key.
 		 */
-	       dentry->d_fsdata = NULL;
-	       if (ext4_encryption_info(dir))
-		       dentry->d_fsdata = (void *) 1;
-	       d_set_d_op(dentry, &ext4_encrypted_d_ops);
-	       if (res && res != -ENOKEY)
-		       return ERR_PTR(res);
-       }
+		if (fscrypt_has_encryption_key(dir))
+			fscrypt_set_encrypted_dentry(dentry);
+		fscrypt_set_d_op(dentry);
+		if (res && res != -ENOKEY)
+			return ERR_PTR(res);
+	}
 
-	if (dentry->d_name.len > EXT4_NAME_LEN)
-		return ERR_PTR(-ENAMETOOLONG);
+       if (dentry->d_name.len > EXT4_NAME_LEN)
+	       return ERR_PTR(-ENAMETOOLONG);
 
 	bh = ext4_find_entry(dir, &dentry->d_name, &de, NULL);
 	if (IS_ERR(bh))
@@ -1608,11 +1610,9 @@ static struct dentry *ext4_lookup(struct inode *dir, struct dentry *dentry, unsi
 		}
 		if (!IS_ERR(inode) && ext4_encrypted_inode(dir) &&
 		    (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode)) &&
-		    !ext4_is_child_context_consistent_with_parent(dir,
-								  inode)) {
+		    !fscrypt_has_permitted_context(dir, inode)) {
 			int nokey = ext4_encrypted_inode(inode) &&
-				!ext4_encryption_info(inode);
-
+				!fscrypt_has_encryption_key(inode);
 			iput(inode);
 			if (nokey)
 				return ERR_PTR(-ENOKEY);
@@ -2689,30 +2689,30 @@ out_stop:
 /*
  * routine to check that the specified directory is empty (for rmdir)
  */
-int ext4_empty_dir(struct inode *inode)
+bool ext4_empty_dir(struct inode *inode)
 {
 	unsigned int offset;
 	struct buffer_head *bh;
 	struct ext4_dir_entry_2 *de, *de1;
 	struct super_block *sb;
-	int err = 0;
 
 	if (ext4_has_inline_data(inode)) {
 		int has_inline_data = 1;
+		int ret;
 
-		err = empty_inline_dir(inode, &has_inline_data);
+		ret = empty_inline_dir(inode, &has_inline_data);
 		if (has_inline_data)
-			return err;
+			return ret;
 	}
 
 	sb = inode->i_sb;
 	if (inode->i_size < EXT4_DIR_REC_LEN(1) + EXT4_DIR_REC_LEN(2)) {
 		EXT4_ERROR_INODE(inode, "invalid size");
-		return 1;
+		return true;
 	}
 	bh = ext4_read_dirblock(inode, 0, EITHER);
 	if (IS_ERR(bh))
-		return 1;
+		return true;
 
 	de = (struct ext4_dir_entry_2 *) bh->b_data;
 	de1 = ext4_next_entry(de, sb->s_blocksize);
@@ -2721,7 +2721,7 @@ int ext4_empty_dir(struct inode *inode)
 			strcmp(".", de->name) || strcmp("..", de1->name)) {
 		ext4_warning_inode(inode, "directory missing '.' and/or '..'");
 		brelse(bh);
-		return 1;
+		return true;
 	}
 	offset = ext4_rec_len_from_disk(de->rec_len, sb->s_blocksize) +
 		 ext4_rec_len_from_disk(de1->rec_len, sb->s_blocksize);
@@ -2729,12 +2729,11 @@ int ext4_empty_dir(struct inode *inode)
 	while (offset < inode->i_size) {
 		if ((void *) de >= (void *) (bh->b_data+sb->s_blocksize)) {
 			unsigned int lblock;
-			err = 0;
 			brelse(bh);
 			lblock = offset >> EXT4_BLOCK_SIZE_BITS(sb);
 			bh = ext4_read_dirblock(inode, lblock, EITHER);
 			if (IS_ERR(bh))
-				return 1;
+				return true;
 			de = (struct ext4_dir_entry_2 *) bh->b_data;
 		}
 		if (ext4_check_dir_entry(inode, NULL, de, bh,
@@ -2746,13 +2745,13 @@ int ext4_empty_dir(struct inode *inode)
 		}
 		if (le32_to_cpu(de->inode)) {
 			brelse(bh);
-			return 0;
+			return false;
 		}
 		offset += ext4_rec_len_from_disk(de->rec_len, sb->s_blocksize);
 		de = ext4_next_entry(de, sb->s_blocksize);
 	}
 	brelse(bh);
-	return 1;
+	return true;
 }
 
 /*
@@ -3075,8 +3074,8 @@ static int ext4_symlink(struct inode *dir,
 	int err, len = strlen(symname);
 	int credits;
 	bool encryption_required;
-	struct ext4_str disk_link;
-	struct ext4_encrypted_symlink_data *sd = NULL;
+	struct fscrypt_str disk_link;
+	struct fscrypt_symlink_data *sd = NULL;
 
 	disk_link.len = len + 1;
 	disk_link.name = (char *) symname;
@@ -3084,13 +3083,13 @@ static int ext4_symlink(struct inode *dir,
 	encryption_required = (ext4_encrypted_inode(dir) ||
 			       DUMMY_ENCRYPTION_ENABLED(EXT4_SB(dir->i_sb)));
 	if (encryption_required) {
-		err = ext4_get_encryption_info(dir);
+		err = fscrypt_get_encryption_info(dir);
 		if (err)
 			return err;
-		if (ext4_encryption_info(dir) == NULL)
+		if (!fscrypt_has_encryption_key(dir))
 			return -EPERM;
-		disk_link.len = (ext4_fname_encrypted_size(dir, len) +
-				 sizeof(struct ext4_encrypted_symlink_data));
+		disk_link.len = (fscrypt_fname_encrypted_size(dir, len) +
+				 sizeof(struct fscrypt_symlink_data));
 		sd = kzalloc(disk_link.len, GFP_KERNEL);
 		if (!sd)
 			return -ENOMEM;
@@ -3138,13 +3137,12 @@ static int ext4_symlink(struct inode *dir,
 
 	if (encryption_required) {
 		struct qstr istr;
-		struct ext4_str ostr;
+		struct fscrypt_str ostr =
+			FSTR_INIT(sd->encrypted_path, disk_link.len);
 
 		istr.name = (const unsigned char *) symname;
 		istr.len = len;
-		ostr.name = sd->encrypted_path;
-		ostr.len = disk_link.len;
-		err = ext4_fname_usr_to_disk(inode, &istr, &ostr);
+		err = fscrypt_fname_usr_to_disk(inode, &istr, &ostr);
 		if (err < 0)
 			goto err_drop_inode;
 		sd->len = cpu_to_le16(ostr.len);
@@ -3233,7 +3231,7 @@ static int ext4_link(struct dentry *old_dentry,
 	if (inode->i_nlink >= EXT4_LINK_MAX)
 		return -EMLINK;
 	if (ext4_encrypted_inode(dir) &&
-	    !ext4_is_child_context_consistent_with_parent(dir, inode))
+			!fscrypt_has_permitted_context(dir, inode))
 		return -EPERM;
 
        if ((ext4_test_inode_flag(dir, EXT4_INODE_PROJINHERIT)) &&
@@ -3556,8 +3554,7 @@ static int ext4_rename(struct inode *old_dir, struct dentry *old_dentry,
 
 	if ((old.dir != new.dir) &&
 	    ext4_encrypted_inode(new.dir) &&
-	    !ext4_is_child_context_consistent_with_parent(new.dir,
-							  old.inode)) {
+	    !fscrypt_has_permitted_context(new.dir, old.inode)) {
 		retval = -EPERM;
 		goto end_rename;
 	}
@@ -3729,10 +3726,8 @@ static int ext4_cross_rename(struct inode *old_dir, struct dentry *old_dentry,
 	if ((ext4_encrypted_inode(old_dir) ||
 	     ext4_encrypted_inode(new_dir)) &&
 	    (old_dir != new_dir) &&
-	    (!ext4_is_child_context_consistent_with_parent(new_dir,
-							   old.inode) ||
-	     !ext4_is_child_context_consistent_with_parent(old_dir,
-							   new.inode)))
+	    (!fscrypt_has_permitted_context(new_dir, old.inode) ||
+	     !fscrypt_has_permitted_context(old_dir, new.inode)))
 		return -EPERM;
 
 	if ((ext4_test_inode_flag(new_dir, EXT4_INODE_PROJINHERIT) &&