From 2c3c1048746a4622d8c89a29670120dc8fab93c4 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 7 Apr 2024 20:49:45 +0200 Subject: Adding upstream version 6.1.76. Signed-off-by: Daniel Baumann --- fs/ecryptfs/read_write.c | 263 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 263 insertions(+) create mode 100644 fs/ecryptfs/read_write.c (limited to 'fs/ecryptfs/read_write.c') diff --git a/fs/ecryptfs/read_write.c b/fs/ecryptfs/read_write.c new file mode 100644 index 000000000..60bdcaddc --- /dev/null +++ b/fs/ecryptfs/read_write.c @@ -0,0 +1,263 @@ +// 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 + */ + +#include +#include +#include + +#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 + * @page_for_lower: The page containing the data to be written to the + * lower file + * @offset_in_page: The offset in the @page_for_lower from which to + * start writing the data + * @size: The amount of data from @page_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 @page_for_lower to the lower inode. + * + * Returns zero on success; non-zero otherwise + */ +int ecryptfs_write_lower_page_segment(struct inode *ecryptfs_inode, + struct page *page_for_lower, + size_t offset_in_page, size_t size) +{ + char *virt; + loff_t offset; + int rc; + + offset = ((((loff_t)page_for_lower->index) << PAGE_SHIFT) + + offset_in_page); + virt = kmap(page_for_lower); + rc = ecryptfs_write_lower(ecryptfs_inode, virt, offset, size); + if (rc > 0) + rc = 0; + kunmap(page_for_lower); + 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 page *ecryptfs_page; + 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)) { + 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_page = ecryptfs_get_locked_page(ecryptfs_inode, + ecryptfs_page_idx); + if (IS_ERR(ecryptfs_page)) { + rc = PTR_ERR(ecryptfs_page); + printk(KERN_ERR "%s: Error getting page at " + "index [%ld] from eCryptfs inode " + "mapping; rc = [%d]\n", __func__, + ecryptfs_page_idx, rc); + goto out; + } + ecryptfs_page_virt = kmap_atomic(ecryptfs_page); + + /* + * 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_atomic(ecryptfs_page_virt); + flush_dcache_page(ecryptfs_page); + SetPageUptodate(ecryptfs_page); + unlock_page(ecryptfs_page); + if (crypt_stat->flags & ECRYPTFS_ENCRYPTED) + rc = ecryptfs_encrypt_page(ecryptfs_page); + else + rc = ecryptfs_write_lower_page_segment(ecryptfs_inode, + ecryptfs_page, + start_offset_in_page, + data_offset); + put_page(ecryptfs_page); + 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 + * @page_for_ecryptfs: The page 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 page *page_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_SHIFT) + offset_in_page); + virt = kmap(page_for_ecryptfs); + rc = ecryptfs_read_lower(virt, offset, size, ecryptfs_inode); + if (rc > 0) + rc = 0; + kunmap(page_for_ecryptfs); + flush_dcache_page(page_for_ecryptfs); + return rc; +} -- cgit v1.2.3