1 // SPDX-License-Identifier: GPL-2.0-or-later
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>
28  * Get one page from cache or lower f/s, return error otherwise.
30  * Returns locked and up-to-date page (if ok), with increased
33 struct page *ecryptfs_get_locked_page(struct inode *inode, loff_t index)  in ecryptfs_get_locked_page()
35 	struct page *page = read_mapping_page(inode->i_mapping, index, NULL);  in ecryptfs_get_locked_page()  local
36 	if (!IS_ERR(page))  in ecryptfs_get_locked_page()
37 		lock_page(page);  in ecryptfs_get_locked_page()
38 	return page;  in ecryptfs_get_locked_page()
43  * @page: Page that is locked before this call is made
44  * @wbc: Write-back control structure
46  * Returns zero on success; non-zero otherwise
49  * the lower filesystem.  In OpenPGP-compatible mode, we operate on
52 static int ecryptfs_writepage(struct page *page, struct writeback_control *wbc)  in ecryptfs_writepage()  argument
56 	rc = ecryptfs_encrypt_page(page);  in ecryptfs_writepage()
59 				"page (upper index [0x%.16lx])\n", page->index);  in ecryptfs_writepage()
60 		ClearPageUptodate(page);  in ecryptfs_writepage()
63 	SetPageUptodate(page);  in ecryptfs_writepage()
65 	unlock_page(page);  in ecryptfs_writepage()
72 	if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR) {  in strip_xattr_flag()
75 		crypt_stat->flags &= ~ECRYPTFS_METADATA_IN_XATTR;  in strip_xattr_flag()
78 		crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;  in strip_xattr_flag()
84  *     Octets 0-7:        Unencrypted file size (big-endian)
85  *     Octets 8-15:       eCryptfs special marker
86  *     Octets 16-19:      Flags
88  *      Octets 17-18:     Reserved
91  *                        Bits 3-8: Reserved
92  *     Octets 20-23:      Header extent size (big-endian)
93  *     Octets 24-25:      Number of header extents at front of file
94  *                        (big-endian)
100  * @page: Sort of a ``virtual'' representation of the encrypted lower
109 ecryptfs_copy_up_encrypted_with_header(struct page *page,  in ecryptfs_copy_up_encrypted_with_header()  argument
114 				       / crypt_stat->extent_size);  in ecryptfs_copy_up_encrypted_with_header()
118 		loff_t view_extent_num = ((((loff_t)page->index)  in ecryptfs_copy_up_encrypted_with_header()
122 			(crypt_stat->metadata_size / crypt_stat->extent_size);  in ecryptfs_copy_up_encrypted_with_header()
128 			page_virt = kmap_atomic(page);  in ecryptfs_copy_up_encrypted_with_header()
135 					page_virt, page->mapping->host);  in ecryptfs_copy_up_encrypted_with_header()
142 			flush_dcache_page(page);  in ecryptfs_copy_up_encrypted_with_header()
151 				((view_extent_num * crypt_stat->extent_size)  in ecryptfs_copy_up_encrypted_with_header()
152 				 - crypt_stat->metadata_size);  in ecryptfs_copy_up_encrypted_with_header()
155 				page, (lower_offset >> PAGE_SHIFT),  in ecryptfs_copy_up_encrypted_with_header()
157 				crypt_stat->extent_size, page->mapping->host);  in ecryptfs_copy_up_encrypted_with_header()
179  * Returns zero on success; non-zero on error.
183 	struct page *page = &folio->page;  in ecryptfs_read_folio()  local
185 		&ecryptfs_inode_to_private(page->mapping->host)->crypt_stat;  in ecryptfs_read_folio()
188 	if (!crypt_stat || !(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {  in ecryptfs_read_folio()
189 		rc = ecryptfs_read_lower_page_segment(page, page->index, 0,  in ecryptfs_read_folio()
191 						      page->mapping->host);  in ecryptfs_read_folio()
192 	} else if (crypt_stat->flags & ECRYPTFS_VIEW_AS_ENCRYPTED) {  in ecryptfs_read_folio()
193 		if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR) {  in ecryptfs_read_folio()
194 			rc = ecryptfs_copy_up_encrypted_with_header(page,  in ecryptfs_read_folio()
207 				page, page->index, 0, PAGE_SIZE,  in ecryptfs_read_folio()
208 				page->mapping->host);  in ecryptfs_read_folio()
210 				printk(KERN_ERR "Error reading page; rc = "  in ecryptfs_read_folio()
216 		rc = ecryptfs_decrypt_page(page);  in ecryptfs_read_folio()
218 			ecryptfs_printk(KERN_ERR, "Error decrypting page; "  in ecryptfs_read_folio()
225 		ClearPageUptodate(page);  in ecryptfs_read_folio()
227 		SetPageUptodate(page);  in ecryptfs_read_folio()
228 	ecryptfs_printk(KERN_DEBUG, "Unlocking page with index = [0x%.16lx]\n",  in ecryptfs_read_folio()
229 			page->index);  in ecryptfs_read_folio()
230 	unlock_page(page);  in ecryptfs_read_folio()
237 static int fill_zeros_to_end_of_page(struct page *page, unsigned int to)  in fill_zeros_to_end_of_page()  argument
239 	struct inode *inode = page->mapping->host;  in fill_zeros_to_end_of_page()
242 	if ((i_size_read(inode) / PAGE_SIZE) != page->index)  in fill_zeros_to_end_of_page()
247 	zero_user_segment(page, end_byte_in_page, PAGE_SIZE);  in fill_zeros_to_end_of_page()
259  * @pagep: Pointer to return the page
264  * Returns zero on success; non-zero otherwise
269 			struct page **pagep, void **fsdata)  in ecryptfs_write_begin()
272 	struct page *page;  in ecryptfs_write_begin()  local
276 	page = grab_cache_page_write_begin(mapping, index);  in ecryptfs_write_begin()
277 	if (!page)  in ecryptfs_write_begin()
278 		return -ENOMEM;  in ecryptfs_write_begin()
279 	*pagep = page;  in ecryptfs_write_begin()
282 	if (!PageUptodate(page)) {  in ecryptfs_write_begin()
284 			&ecryptfs_inode_to_private(mapping->host)->crypt_stat;  in ecryptfs_write_begin()
286 		if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {  in ecryptfs_write_begin()
288 				page, index, 0, PAGE_SIZE, mapping->host);  in ecryptfs_write_begin()
291 				       "lower page segment; rc = [%d]\n",  in ecryptfs_write_begin()
293 				ClearPageUptodate(page);  in ecryptfs_write_begin()
296 				SetPageUptodate(page);  in ecryptfs_write_begin()
297 		} else if (crypt_stat->flags & ECRYPTFS_VIEW_AS_ENCRYPTED) {  in ecryptfs_write_begin()
298 			if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR) {  in ecryptfs_write_begin()
300 					page, crypt_stat);  in ecryptfs_write_begin()
308 					ClearPageUptodate(page);  in ecryptfs_write_begin()
311 				SetPageUptodate(page);  in ecryptfs_write_begin()
314 					page, index, 0, PAGE_SIZE,  in ecryptfs_write_begin()
315 					mapping->host);  in ecryptfs_write_begin()
318 					       "page; rc = [%d]\n",  in ecryptfs_write_begin()
320 					ClearPageUptodate(page);  in ecryptfs_write_begin()
323 				SetPageUptodate(page);  in ecryptfs_write_begin()
327 			    >= i_size_read(page->mapping->host)) {  in ecryptfs_write_begin()
328 				zero_user(page, 0, PAGE_SIZE);  in ecryptfs_write_begin()
329 				SetPageUptodate(page);  in ecryptfs_write_begin()
331 				rc = ecryptfs_decrypt_page(page);  in ecryptfs_write_begin()
334 					       "page at index [%ld]; "  in ecryptfs_write_begin()
336 					       __func__, page->index, rc);  in ecryptfs_write_begin()
337 					ClearPageUptodate(page);  in ecryptfs_write_begin()
340 				SetPageUptodate(page);  in ecryptfs_write_begin()
344 	/* If creating a page or more of holes, zero them out via truncate.  in ecryptfs_write_begin()
347 		if (prev_page_end_size > i_size_read(page->mapping->host)) {  in ecryptfs_write_begin()
348 			rc = ecryptfs_truncate(file->f_path.dentry,  in ecryptfs_write_begin()
359 	/* Writing to a new page, and creating a small hole from start  in ecryptfs_write_begin()
360 	 * of page?  Zero it out. */  in ecryptfs_write_begin()
361 	if ((i_size_read(mapping->host) == prev_page_end_size)  in ecryptfs_write_begin()
363 		zero_user(page, 0, PAGE_SIZE);  in ecryptfs_write_begin()
366 		unlock_page(page);  in ecryptfs_write_begin()
367 		put_page(page);  in ecryptfs_write_begin()
376  * Writes the lower file size to the first 8 bytes of the header.
378  * Returns zero on success; non-zero on error.
387 		rc = -ENOMEM;  in ecryptfs_write_inode_size_to_header()
395 		printk(KERN_ERR "%s: Error writing file size to header; "  in ecryptfs_write_inode_size_to_header()
407 	ssize_t size;  in ecryptfs_write_inode_size_to_xattr()  local
410 		ecryptfs_inode_to_private(ecryptfs_inode)->lower_file->f_path.dentry;  in ecryptfs_write_inode_size_to_xattr()
414 	if (!(lower_inode->i_opflags & IOP_XATTR)) {  in ecryptfs_write_inode_size_to_xattr()
417 		rc = -ENOSYS;  in ecryptfs_write_inode_size_to_xattr()
422 		rc = -ENOMEM;  in ecryptfs_write_inode_size_to_xattr()
426 	size = __vfs_getxattr(lower_dentry, lower_inode, ECRYPTFS_XATTR_NAME,  in ecryptfs_write_inode_size_to_xattr()
428 	if (size < 0)  in ecryptfs_write_inode_size_to_xattr()
429 		size = 8;  in ecryptfs_write_inode_size_to_xattr()
432 			    ECRYPTFS_XATTR_NAME, xattr_virt, size, 0);  in ecryptfs_write_inode_size_to_xattr()
435 		printk(KERN_ERR "Error whilst attempting to write inode size "  in ecryptfs_write_inode_size_to_xattr()
446 	crypt_stat = &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;  in ecryptfs_write_inode_size_to_metadata()
447 	BUG_ON(!(crypt_stat->flags & ECRYPTFS_ENCRYPTED));  in ecryptfs_write_inode_size_to_metadata()
448 	if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)  in ecryptfs_write_inode_size_to_metadata()
461  * @page: The eCryptfs page
467 			struct page *page, void *fsdata)  in ecryptfs_write_end()  argument
470 	unsigned from = pos & (PAGE_SIZE - 1);  in ecryptfs_write_end()
472 	struct inode *ecryptfs_inode = mapping->host;  in ecryptfs_write_end()
474 		&ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;  in ecryptfs_write_end()
478 			"(page w/ index = [0x%.16lx], to = [%d])\n", index, to);  in ecryptfs_write_end()
479 	if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {  in ecryptfs_write_end()
480 		rc = ecryptfs_write_lower_page_segment(ecryptfs_inode, page, 0,  in ecryptfs_write_end()
489 	if (!PageUptodate(page)) {  in ecryptfs_write_end()
494 		SetPageUptodate(page);  in ecryptfs_write_end()
496 	/* Fills in zeros if 'to' goes beyond inode size */  in ecryptfs_write_end()
497 	rc = fill_zeros_to_end_of_page(page, to);  in ecryptfs_write_end()
500 			"zeros in page with index = [0x%.16lx]\n", index);  in ecryptfs_write_end()
503 	rc = ecryptfs_encrypt_page(page);  in ecryptfs_write_end()
505 		ecryptfs_printk(KERN_WARNING, "Error encrypting page (upper "  in ecryptfs_write_end()
511 		ecryptfs_printk(KERN_DEBUG, "Expanded file size to "  in ecryptfs_write_end()
517 		printk(KERN_ERR "Error writing inode size to metadata; "  in ecryptfs_write_end()
522 	unlock_page(page);  in ecryptfs_write_end()
523 	put_page(page);  in ecryptfs_write_end()
529 	struct inode *lower_inode = ecryptfs_inode_to_lower(mapping->host);  in ecryptfs_bmap()
544 	 * address_space_operations without the ->dirty_folio method was