1 // SPDX-License-Identifier: GPL-2.0-or-later
5  * decryption of the file data as it passes between the lower
8  * Copyright (C) 1997-2003 Erez Zadok
9  * Copyright (C) 2001-2003 Stony Brook University
10  * Copyright (C) 2004-2007 International Business Machines Corp.
16 #include <linux/page-flags.h>
26  * This is where we encrypt the data and pass the encrypted data to
27  * the lower filesystem.  In OpenPGP-compatible mode, we operate on
30 static int ecryptfs_writepages(struct address_space *mapping,  in ecryptfs_writepages()  argument
36 	while ((folio = writeback_iter(mapping, wbc, folio, &error))) {  in ecryptfs_writepages()
41 				folio->index);  in ecryptfs_writepages()
43 			mapping_set_error(mapping, error);  in ecryptfs_writepages()
54 	if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR) {  in strip_xattr_flag()
57 		crypt_stat->flags &= ~ECRYPTFS_METADATA_IN_XATTR;  in strip_xattr_flag()
60 		crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;  in strip_xattr_flag()
66  *     Octets 0-7:        Unencrypted file size (big-endian)
67  *     Octets 8-15:       eCryptfs special marker
68  *     Octets 16-19:      Flags
70  *      Octets 17-18:     Reserved
73  *                        Bits 3-8: Reserved
74  *     Octets 20-23:      Header extent size (big-endian)
75  *     Octets 24-25:      Number of header extents at front of file
76  *                        (big-endian)
96 				       / crypt_stat->extent_size);  in ecryptfs_copy_up_encrypted_with_header()
100 		loff_t view_extent_num = ((loff_t)folio->index  in ecryptfs_copy_up_encrypted_with_header()
104 			(crypt_stat->metadata_size / crypt_stat->extent_size);  in ecryptfs_copy_up_encrypted_with_header()
117 					page_virt, folio->mapping->host);  in ecryptfs_copy_up_encrypted_with_header()
131 			/* This is an encrypted data extent */  in ecryptfs_copy_up_encrypted_with_header()
133 				((view_extent_num * crypt_stat->extent_size)  in ecryptfs_copy_up_encrypted_with_header()
134 				 - crypt_stat->metadata_size);  in ecryptfs_copy_up_encrypted_with_header()
139 				crypt_stat->extent_size, folio->mapping->host);  in ecryptfs_copy_up_encrypted_with_header()
157  * @folio: Folio from eCryptfs inode mapping into which to stick the read data
161  * Returns zero on success; non-zero on error.
165 	struct inode *inode = folio->mapping->host;  in ecryptfs_read_folio()
167 		&ecryptfs_inode_to_private(inode)->crypt_stat;  in ecryptfs_read_folio()
170 	if (!crypt_stat || !(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {  in ecryptfs_read_folio()
171 		err = ecryptfs_read_lower_page_segment(folio, folio->index, 0,  in ecryptfs_read_folio()
173 	} else if (crypt_stat->flags & ECRYPTFS_VIEW_AS_ENCRYPTED) {  in ecryptfs_read_folio()
174 		if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR) {  in ecryptfs_read_folio()
188 					folio->index, 0, folio_size(folio),  in ecryptfs_read_folio()
206 			folio->index);  in ecryptfs_read_folio()
216 	struct inode *inode = folio->mapping->host;  in fill_zeros_to_end_of_page()
219 	if ((i_size_read(inode) / PAGE_SIZE) != folio->index)  in fill_zeros_to_end_of_page()
232  * @mapping: The eCryptfs object
236  * @fsdata: Pointer to return fs data (unused)
240  * Returns zero on success; non-zero otherwise
243 			struct address_space *mapping,  in ecryptfs_write_begin()  argument
252 	folio = __filemap_get_folio(mapping, index, FGP_WRITEBEGIN,  in ecryptfs_write_begin()
253 			mapping_gfp_mask(mapping));  in ecryptfs_write_begin()
261 			&ecryptfs_inode_to_private(mapping->host)->crypt_stat;  in ecryptfs_write_begin()
263 		if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {  in ecryptfs_write_begin()
265 				folio, index, 0, PAGE_SIZE, mapping->host);  in ecryptfs_write_begin()
274 		} else if (crypt_stat->flags & ECRYPTFS_VIEW_AS_ENCRYPTED) {  in ecryptfs_write_begin()
275 			if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR) {  in ecryptfs_write_begin()
292 					mapping->host);  in ecryptfs_write_begin()
304 			    >= i_size_read(mapping->host)) {  in ecryptfs_write_begin()
313 					       __func__, folio->index, rc);  in ecryptfs_write_begin()
324 		if (prev_page_end_size > i_size_read(mapping->host)) {  in ecryptfs_write_begin()
325 			rc = ecryptfs_truncate(file->f_path.dentry,  in ecryptfs_write_begin()
338 	if ((i_size_read(mapping->host) == prev_page_end_size)  in ecryptfs_write_begin()
354  * Returns zero on success; non-zero on error.
363 		rc = -ENOMEM;  in ecryptfs_write_inode_size_to_header()
386 		ecryptfs_inode_to_private(ecryptfs_inode)->lower_file->f_path.dentry;  in ecryptfs_write_inode_size_to_xattr()
390 	if (!(lower_inode->i_opflags & IOP_XATTR)) {  in ecryptfs_write_inode_size_to_xattr()
393 		rc = -ENOSYS;  in ecryptfs_write_inode_size_to_xattr()
398 		rc = -ENOMEM;  in ecryptfs_write_inode_size_to_xattr()
422 	crypt_stat = &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;  in ecryptfs_write_inode_size_to_metadata()
423 	BUG_ON(!(crypt_stat->flags & ECRYPTFS_ENCRYPTED));  in ecryptfs_write_inode_size_to_metadata()
424 	if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)  in ecryptfs_write_inode_size_to_metadata()
433  * @mapping: The eCryptfs object
435  * @len: The length of the data (unused)
436  * @copied: The amount of data copied
441 			struct address_space *mapping,  in ecryptfs_write_end()  argument
446 	unsigned from = pos & (PAGE_SIZE - 1);  in ecryptfs_write_end()
448 	struct inode *ecryptfs_inode = mapping->host;  in ecryptfs_write_end()
450 		&ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;  in ecryptfs_write_end()
455 	if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {  in ecryptfs_write_end()
503 static sector_t ecryptfs_bmap(struct address_space *mapping, sector_t block)  in ecryptfs_bmap()  argument
505 	struct inode *lower_inode = ecryptfs_inode_to_lower(mapping->host);  in ecryptfs_bmap()
520 	 * address_space_operations without the ->dirty_folio method was