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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264// SPDX-License-Identifier: GPL-2.0-or-later/* * eCryptfs: Linux filesystem encryption layer * * Copyright (C) 2007 International Business Machines Corp. * Author(s): Michael A. Halcrow <mahalcro@us.ibm.com> */
#include <linux/fs.h>#include <linux/pagemap.h>#include <linux/sched/signal.h>
#include "ecryptfs_kernel.h"
/** * ecryptfs_write_lower * @ecryptfs_inode: The eCryptfs inode * @data: Data to write * @offset: Byte offset in the lower file to which to write the data * @size: Number of bytes from @data to write at @offset in the lower * file * * Write data to the lower file. * * Returns bytes written on success; less than zero on error */int ecryptfs_write_lower(struct inode *ecryptfs_inode, char *data, loff_t offset, size_t size){ struct file *lower_file; ssize_t rc;
lower_file = ecryptfs_inode_to_private(ecryptfs_inode)->lower_file; if (!lower_file) return -EIO; rc = kernel_write(lower_file, data, size, &offset); mark_inode_dirty_sync(ecryptfs_inode); return rc;}
/** * ecryptfs_write_lower_page_segment * @ecryptfs_inode: The eCryptfs inode * @folio_for_lower: The folio containing the data to be written to the * lower file * @offset_in_page: The offset in the @folio_for_lower from which to * start writing the data * @size: The amount of data from @folio_for_lower to write to the * lower file * * Determines the byte offset in the file for the given page and * offset within the page, maps the page, and makes the call to write * the contents of @folio_for_lower to the lower inode. * * Returns zero on success; non-zero otherwise */int ecryptfs_write_lower_page_segment(struct inode *ecryptfs_inode, struct folio *folio_for_lower, size_t offset_in_page, size_t size){ char *virt; loff_t offset; int rc;
offset = (loff_t)folio_for_lower->index * PAGE_SIZE + offset_in_page; virt = kmap_local_folio(folio_for_lower, 0); rc = ecryptfs_write_lower(ecryptfs_inode, virt, offset, size); if (rc > 0) rc = 0; kunmap_local(virt); return rc;}
/** * ecryptfs_write * @ecryptfs_inode: The eCryptfs file into which to write * @data: Virtual address where data to write is located * @offset: Offset in the eCryptfs file at which to begin writing the * data from @data * @size: The number of bytes to write from @data * * Write an arbitrary amount of data to an arbitrary location in the * eCryptfs inode page cache. This is done on a page-by-page, and then * by an extent-by-extent, basis; individual extents are encrypted and * written to the lower page cache (via VFS writes). This function * takes care of all the address translation to locations in the lower * filesystem; it also handles truncate events, writing out zeros * where necessary. * * Returns zero on success; non-zero otherwise */int ecryptfs_write(struct inode *ecryptfs_inode, char *data, loff_t offset, size_t size){ struct ecryptfs_crypt_stat *crypt_stat; char *ecryptfs_page_virt; loff_t ecryptfs_file_size = i_size_read(ecryptfs_inode); loff_t data_offset = 0; loff_t pos; int rc = 0;
crypt_stat = &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat; /* * if we are writing beyond current size, then start pos * at the current size - we'll fill in zeros from there. */ if (offset > ecryptfs_file_size) pos = ecryptfs_file_size; else pos = offset; while (pos < (offset + size)) { struct folio *ecryptfs_folio; pgoff_t ecryptfs_page_idx = (pos >> PAGE_SHIFT); size_t start_offset_in_page = (pos & ~PAGE_MASK); size_t num_bytes = (PAGE_SIZE - start_offset_in_page); loff_t total_remaining_bytes = ((offset + size) - pos);
if (fatal_signal_pending(current)) { rc = -EINTR; break; }
if (num_bytes > total_remaining_bytes) num_bytes = total_remaining_bytes; if (pos < offset) { /* remaining zeros to write, up to destination offset */ loff_t total_remaining_zeros = (offset - pos);
if (num_bytes > total_remaining_zeros) num_bytes = total_remaining_zeros; } ecryptfs_folio = read_mapping_folio(ecryptfs_inode->i_mapping, ecryptfs_page_idx, NULL); if (IS_ERR(ecryptfs_folio)) { rc = PTR_ERR(ecryptfs_folio); printk(KERN_ERR "%s: Error getting page at " "index [%ld] from eCryptfs inode " "mapping; rc = [%d]\n", __func__, ecryptfs_page_idx, rc); goto out; } folio_lock(ecryptfs_folio); ecryptfs_page_virt = kmap_local_folio(ecryptfs_folio, 0);
/* * pos: where we're now writing, offset: where the request was * If current pos is before request, we are filling zeros * If we are at or beyond request, we are writing the *data* * If we're in a fresh page beyond eof, zero it in either case */ if (pos < offset || !start_offset_in_page) { /* We are extending past the previous end of the file. * Fill in zero values to the end of the page */ memset(((char *)ecryptfs_page_virt + start_offset_in_page), 0, PAGE_SIZE - start_offset_in_page); }
/* pos >= offset, we are now writing the data request */ if (pos >= offset) { memcpy(((char *)ecryptfs_page_virt + start_offset_in_page), (data + data_offset), num_bytes); data_offset += num_bytes; } kunmap_local(ecryptfs_page_virt); flush_dcache_folio(ecryptfs_folio); folio_mark_uptodate(ecryptfs_folio); folio_unlock(ecryptfs_folio); if (crypt_stat->flags & ECRYPTFS_ENCRYPTED) rc = ecryptfs_encrypt_page(ecryptfs_folio); else rc = ecryptfs_write_lower_page_segment(ecryptfs_inode, ecryptfs_folio, start_offset_in_page, data_offset); folio_put(ecryptfs_folio); if (rc) { printk(KERN_ERR "%s: Error encrypting " "page; rc = [%d]\n", __func__, rc); goto out; } pos += num_bytes; } if (pos > ecryptfs_file_size) { i_size_write(ecryptfs_inode, pos); if (crypt_stat->flags & ECRYPTFS_ENCRYPTED) { int rc2;
rc2 = ecryptfs_write_inode_size_to_metadata( ecryptfs_inode); if (rc2) { printk(KERN_ERR "Problem with " "ecryptfs_write_inode_size_to_metadata; " "rc = [%d]\n", rc2); if (!rc) rc = rc2; goto out; } } }out: return rc;}
/** * ecryptfs_read_lower * @data: The read data is stored here by this function * @offset: Byte offset in the lower file from which to read the data * @size: Number of bytes to read from @offset of the lower file and * store into @data * @ecryptfs_inode: The eCryptfs inode * * Read @size bytes of data at byte offset @offset from the lower * inode into memory location @data. * * Returns bytes read on success; 0 on EOF; less than zero on error */int ecryptfs_read_lower(char *data, loff_t offset, size_t size, struct inode *ecryptfs_inode){ struct file *lower_file; lower_file = ecryptfs_inode_to_private(ecryptfs_inode)->lower_file; if (!lower_file) return -EIO; return kernel_read(lower_file, data, size, &offset);}
/** * ecryptfs_read_lower_page_segment * @folio_for_ecryptfs: The folio into which data for eCryptfs will be * written * @page_index: Page index in @page_for_ecryptfs from which to start * writing * @offset_in_page: Offset in @page_for_ecryptfs from which to start * writing * @size: The number of bytes to write into @page_for_ecryptfs * @ecryptfs_inode: The eCryptfs inode * * Determines the byte offset in the file for the given page and * offset within the page, maps the page, and makes the call to read * the contents of @page_for_ecryptfs from the lower inode. * * Returns zero on success; non-zero otherwise */int ecryptfs_read_lower_page_segment(struct folio *folio_for_ecryptfs, pgoff_t page_index, size_t offset_in_page, size_t size, struct inode *ecryptfs_inode){ char *virt; loff_t offset; int rc;
offset = (loff_t)page_index * PAGE_SIZE + offset_in_page; virt = kmap_local_folio(folio_for_ecryptfs, 0); rc = ecryptfs_read_lower(virt, offset, size, ecryptfs_inode); if (rc > 0) rc = 0; kunmap_local(virt); flush_dcache_folio(folio_for_ecryptfs); return rc;}