#include <linux/scatterlist.h>
#include "ecryptfs_kernel.h"
-struct kmem_cache *ecryptfs_lower_page_cache;
-
/**
- * ecryptfs_get1page
+ * ecryptfs_get_locked_page
*
* Get one page from cache or lower f/s, return error otherwise.
*
- * Returns unlocked and up-to-date page (if ok), with increased
+ * Returns locked and up-to-date page (if ok), with increased
* refcnt.
*/
-struct page *ecryptfs_get1page(struct file *file, loff_t index)
+struct page *ecryptfs_get_locked_page(struct file *file, loff_t index)
{
struct dentry *dentry;
struct inode *inode;
struct address_space *mapping;
+ struct page *page;
dentry = file->f_path.dentry;
inode = dentry->d_inode;
mapping = inode->i_mapping;
- return read_mapping_page(mapping, index, (void *)file);
-}
-
-/**
- * ecryptfs_fill_zeros
- * @file: The ecryptfs file
- * @new_length: The new length of the data in the underlying file;
- * everything between the prior end of the file and the
- * new end of the file will be filled with zero's.
- * new_length must be greater than current length
- *
- * Function for handling lseek-ing past the end of the file.
- *
- * This function does not support shrinking, only growing a file.
- *
- * Returns zero on success; non-zero otherwise.
- */
-int ecryptfs_fill_zeros(struct file *file, loff_t new_length)
-{
- int rc = 0;
- struct dentry *dentry = file->f_path.dentry;
- struct inode *inode = dentry->d_inode;
- pgoff_t old_end_page_index = 0;
- pgoff_t index = old_end_page_index;
- int old_end_pos_in_page = -1;
- pgoff_t new_end_page_index;
- int new_end_pos_in_page;
- loff_t cur_length = i_size_read(inode);
-
- if (cur_length != 0) {
- index = old_end_page_index =
- ((cur_length - 1) >> PAGE_CACHE_SHIFT);
- old_end_pos_in_page = ((cur_length - 1) & ~PAGE_CACHE_MASK);
- }
- new_end_page_index = ((new_length - 1) >> PAGE_CACHE_SHIFT);
- new_end_pos_in_page = ((new_length - 1) & ~PAGE_CACHE_MASK);
- ecryptfs_printk(KERN_DEBUG, "old_end_page_index = [0x%.16x]; "
- "old_end_pos_in_page = [%d]; "
- "new_end_page_index = [0x%.16x]; "
- "new_end_pos_in_page = [%d]\n",
- old_end_page_index, old_end_pos_in_page,
- new_end_page_index, new_end_pos_in_page);
- if (old_end_page_index == new_end_page_index) {
- /* Start and end are in the same page; we just need to
- * set a portion of the existing page to zero's */
- rc = ecryptfs_write_zeros(file, index,
- (old_end_pos_in_page + 1),
- (new_end_pos_in_page
- - old_end_pos_in_page));
- if (rc)
- ecryptfs_printk(KERN_ERR, "ecryptfs_write_zeros("
- "file=[%p], "
- "index=[0x%.16x], "
- "old_end_pos_in_page=[d], "
- "(PAGE_CACHE_SIZE - new_end_pos_in_page"
- "=[%d]"
- ")=[d]) returned [%d]\n", file, index,
- old_end_pos_in_page,
- new_end_pos_in_page,
- (PAGE_CACHE_SIZE - new_end_pos_in_page),
- rc);
- goto out;
- }
- /* Fill the remainder of the previous last page with zeros */
- rc = ecryptfs_write_zeros(file, index, (old_end_pos_in_page + 1),
- ((PAGE_CACHE_SIZE - 1) - old_end_pos_in_page));
- if (rc) {
- ecryptfs_printk(KERN_ERR, "ecryptfs_write_zeros(file=[%p], "
- "index=[0x%.16x], old_end_pos_in_page=[d], "
- "(PAGE_CACHE_SIZE - old_end_pos_in_page)=[d]) "
- "returned [%d]\n", file, index,
- old_end_pos_in_page,
- (PAGE_CACHE_SIZE - old_end_pos_in_page), rc);
- goto out;
- }
- index++;
- while (index < new_end_page_index) {
- /* Fill all intermediate pages with zeros */
- rc = ecryptfs_write_zeros(file, index, 0, PAGE_CACHE_SIZE);
- if (rc) {
- ecryptfs_printk(KERN_ERR, "ecryptfs_write_zeros("
- "file=[%p], "
- "index=[0x%.16x], "
- "old_end_pos_in_page=[d], "
- "(PAGE_CACHE_SIZE - new_end_pos_in_page"
- "=[%d]"
- ")=[d]) returned [%d]\n", file, index,
- old_end_pos_in_page,
- new_end_pos_in_page,
- (PAGE_CACHE_SIZE - new_end_pos_in_page),
- rc);
- goto out;
- }
- index++;
- }
- /* Fill the portion at the beginning of the last new page with
- * zero's */
- rc = ecryptfs_write_zeros(file, index, 0, (new_end_pos_in_page + 1));
- if (rc) {
- ecryptfs_printk(KERN_ERR, "ecryptfs_write_zeros(file="
- "[%p], index=[0x%.16x], 0, "
- "new_end_pos_in_page=[%d]"
- "returned [%d]\n", file, index,
- new_end_pos_in_page, rc);
- goto out;
- }
-out:
- return rc;
+ page = read_mapping_page(mapping, index, (void *)file);
+ if (!IS_ERR(page))
+ lock_page(page);
+ return page;
}
/**
}
/**
- * Reads the data from the lower file file at index lower_page_index
- * and copies that data into page.
- *
- * @param page Page to fill
- * @param lower_page_index Index of the page in the lower file to get
- */
-int ecryptfs_do_readpage(struct file *file, struct page *page,
- pgoff_t lower_page_index)
-{
- int rc;
- struct dentry *dentry;
- struct file *lower_file;
- struct dentry *lower_dentry;
- struct inode *inode;
- struct inode *lower_inode;
- char *page_data;
- struct page *lower_page = NULL;
- char *lower_page_data;
- const struct address_space_operations *lower_a_ops;
-
- dentry = file->f_path.dentry;
- lower_file = ecryptfs_file_to_lower(file);
- lower_dentry = ecryptfs_dentry_to_lower(dentry);
- inode = dentry->d_inode;
- lower_inode = ecryptfs_inode_to_lower(inode);
- lower_a_ops = lower_inode->i_mapping->a_ops;
- lower_page = read_cache_page(lower_inode->i_mapping, lower_page_index,
- (filler_t *)lower_a_ops->readpage,
- (void *)lower_file);
- if (IS_ERR(lower_page)) {
- rc = PTR_ERR(lower_page);
- lower_page = NULL;
- ecryptfs_printk(KERN_ERR, "Error reading from page cache\n");
- goto out;
- }
- page_data = kmap_atomic(page, KM_USER0);
- lower_page_data = kmap_atomic(lower_page, KM_USER1);
- memcpy(page_data, lower_page_data, PAGE_CACHE_SIZE);
- kunmap_atomic(lower_page_data, KM_USER1);
- kunmap_atomic(page_data, KM_USER0);
- flush_dcache_page(page);
- rc = 0;
-out:
- if (likely(lower_page))
- page_cache_release(lower_page);
- if (rc == 0)
- SetPageUptodate(page);
- else
- ClearPageUptodate(page);
- return rc;
-}
-/**
* Header Extent:
* Octets 0-7: Unencrypted file size (big-endian)
* Octets 8-15: eCryptfs special marker
struct ecryptfs_crypt_stat *crypt_stat)
{
size_t written;
- int save_num_header_extents_at_front =
- crypt_stat->num_header_extents_at_front;
+ size_t save_num_header_bytes_at_front =
+ crypt_stat->num_header_bytes_at_front;
- crypt_stat->num_header_extents_at_front = 1;
+ crypt_stat->num_header_bytes_at_front =
+ ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
ecryptfs_write_header_metadata(page_virt + 20, crypt_stat, &written);
- crypt_stat->num_header_extents_at_front =
- save_num_header_extents_at_front;
+ crypt_stat->num_header_bytes_at_front =
+ save_num_header_bytes_at_front;
}
/**
loff_t view_extent_num = ((((loff_t)page->index)
* num_extents_per_page)
+ extent_num_in_page);
+ size_t num_header_extents_at_front =
+ (crypt_stat->num_header_bytes_at_front
+ / crypt_stat->extent_size);
- if (view_extent_num < crypt_stat->num_header_extents_at_front) {
+ if (view_extent_num < num_header_extents_at_front) {
/* This is a header extent */
char *page_virt;
kunmap_atomic(page_virt, KM_USER0);
flush_dcache_page(page);
if (rc) {
- ClearPageUptodate(page);
printk(KERN_ERR "%s: Error reading xattr "
- "region; rc = [%d]\n", __FUNCTION__, rc);
+ "region; rc = [%d]\n", __func__, rc);
goto out;
}
- SetPageUptodate(page);
} else {
/* This is an encrypted data extent */
loff_t lower_offset =
- ((view_extent_num -
- crypt_stat->num_header_extents_at_front)
- * crypt_stat->extent_size);
+ ((view_extent_num * crypt_stat->extent_size)
+ - crypt_stat->num_header_bytes_at_front);
rc = ecryptfs_read_lower_page_segment(
page, (lower_offset >> PAGE_CACHE_SHIFT),
if (rc) {
printk(KERN_ERR "%s: Error attempting to read "
"extent at offset [%lld] in the lower "
- "file; rc = [%d]\n", __FUNCTION__,
+ "file; rc = [%d]\n", __func__,
lower_offset, rc);
goto out;
}
"the encrypted content from the lower "
"file whilst inserting the metadata "
"from the xattr into the header; rc = "
- "[%d]\n", __FUNCTION__, rc);
+ "[%d]\n", __func__, rc);
goto out;
}
}
}
out:
+ if (rc)
+ ClearPageUptodate(page);
+ else
+ SetPageUptodate(page);
ecryptfs_printk(KERN_DEBUG, "Unlocking page with index = [0x%.16x]\n",
page->index);
unlock_page(page);
end_byte_in_page = i_size_read(inode) % PAGE_CACHE_SIZE;
if (to > end_byte_in_page)
end_byte_in_page = to;
- zero_user_page(page, end_byte_in_page,
- PAGE_CACHE_SIZE - end_byte_in_page, KM_USER0);
+ zero_user_segment(page, end_byte_in_page, PAGE_CACHE_SIZE);
out:
return 0;
}
/**
- * eCryptfs does not currently support holes. When writing after a
- * seek past the end of the file, eCryptfs fills in 0's through to the
- * current location. The code to fill in the 0's to all the
- * intermediate pages calls ecryptfs_prepare_write_no_truncate().
+ * ecryptfs_prepare_write
+ * @file: The eCryptfs file
+ * @page: The eCryptfs page
+ * @from: The start byte from which we will write
+ * @to: The end byte to which we will write
+ *
+ * This function must zero any hole we create
+ *
+ * Returns zero on success; non-zero otherwise
*/
-static int
-ecryptfs_prepare_write_no_truncate(struct file *file, struct page *page,
- unsigned from, unsigned to)
-{
- int rc = 0;
-
- if (from == 0 && to == PAGE_CACHE_SIZE)
- goto out; /* If we are writing a full page, it will be
- up to date. */
- if (!PageUptodate(page))
- rc = ecryptfs_do_readpage(file, page, page->index);
-out:
- return rc;
-}
-
static int ecryptfs_prepare_write(struct file *file, struct page *page,
unsigned from, unsigned to)
{
+ loff_t prev_page_end_size;
int rc = 0;
- if (from == 0 && to == PAGE_CACHE_SIZE)
- goto out; /* If we are writing a full page, it will be
- up to date. */
- if (!PageUptodate(page))
- rc = ecryptfs_read_lower_page_segment(page, page->index, 0,
- PAGE_CACHE_SIZE,
- page->mapping->host);
- if (page->index != 0) {
- loff_t end_of_prev_pg_pos =
- (((loff_t)page->index << PAGE_CACHE_SHIFT) - 1);
+ if (!PageUptodate(page)) {
+ struct ecryptfs_crypt_stat *crypt_stat =
+ &ecryptfs_inode_to_private(
+ file->f_path.dentry->d_inode)->crypt_stat;
- if (end_of_prev_pg_pos > i_size_read(page->mapping->host)) {
+ if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)
+ || (crypt_stat->flags & ECRYPTFS_NEW_FILE)) {
+ rc = ecryptfs_read_lower_page_segment(
+ page, page->index, 0, PAGE_CACHE_SIZE,
+ page->mapping->host);
+ if (rc) {
+ printk(KERN_ERR "%s: Error attemping to read "
+ "lower page segment; rc = [%d]\n",
+ __func__, rc);
+ ClearPageUptodate(page);
+ goto out;
+ } else
+ SetPageUptodate(page);
+ } else if (crypt_stat->flags & ECRYPTFS_VIEW_AS_ENCRYPTED) {
+ if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR) {
+ rc = ecryptfs_copy_up_encrypted_with_header(
+ page, crypt_stat);
+ if (rc) {
+ printk(KERN_ERR "%s: Error attempting "
+ "to copy the encrypted content "
+ "from the lower file whilst "
+ "inserting the metadata from "
+ "the xattr into the header; rc "
+ "= [%d]\n", __func__, rc);
+ ClearPageUptodate(page);
+ goto out;
+ }
+ SetPageUptodate(page);
+ } else {
+ rc = ecryptfs_read_lower_page_segment(
+ page, page->index, 0, PAGE_CACHE_SIZE,
+ page->mapping->host);
+ if (rc) {
+ printk(KERN_ERR "%s: Error reading "
+ "page; rc = [%d]\n",
+ __func__, rc);
+ ClearPageUptodate(page);
+ goto out;
+ }
+ SetPageUptodate(page);
+ }
+ } else {
+ rc = ecryptfs_decrypt_page(page);
+ if (rc) {
+ printk(KERN_ERR "%s: Error decrypting page "
+ "at index [%ld]; rc = [%d]\n",
+ __func__, page->index, rc);
+ ClearPageUptodate(page);
+ goto out;
+ }
+ SetPageUptodate(page);
+ }
+ }
+ prev_page_end_size = ((loff_t)page->index << PAGE_CACHE_SHIFT);
+ /* If creating a page or more of holes, zero them out via truncate.
+ * Note, this will increase i_size. */
+ if (page->index != 0) {
+ if (prev_page_end_size > i_size_read(page->mapping->host)) {
rc = ecryptfs_truncate(file->f_path.dentry,
- end_of_prev_pg_pos);
+ prev_page_end_size);
if (rc) {
- printk(KERN_ERR "Error on attempt to "
+ printk(KERN_ERR "%s: Error on attempt to "
"truncate to (higher) offset [%lld];"
- " rc = [%d]\n", end_of_prev_pg_pos, rc);
+ " rc = [%d]\n", __func__,
+ prev_page_end_size, rc);
goto out;
}
}
- if (end_of_prev_pg_pos + 1 > i_size_read(page->mapping->host))
- zero_user_page(page, 0, PAGE_CACHE_SIZE, KM_USER0);
}
+ /* Writing to a new page, and creating a small hole from start
+ * of page? Zero it out. */
+ if ((i_size_read(page->mapping->host) == prev_page_end_size)
+ && (from != 0))
+ zero_user(page, 0, PAGE_CACHE_SIZE);
out:
return rc;
}
-int ecryptfs_writepage_and_release_lower_page(struct page *lower_page,
- struct inode *lower_inode,
- struct writeback_control *wbc)
-{
- int rc = 0;
-
- rc = lower_inode->i_mapping->a_ops->writepage(lower_page, wbc);
- if (rc) {
- ecryptfs_printk(KERN_ERR, "Error calling lower writepage(); "
- "rc = [%d]\n", rc);
- goto out;
- }
- lower_inode->i_mtime = lower_inode->i_ctime = CURRENT_TIME;
- page_cache_release(lower_page);
-out:
- return rc;
-}
-
-static void ecryptfs_release_lower_page(struct page *lower_page)
-{
- unlock_page(lower_page);
- page_cache_release(lower_page);
-}
-
/**
* ecryptfs_write_inode_size_to_header
*
kfree(file_size_virt);
if (rc)
printk(KERN_ERR "%s: Error writing file size to header; "
- "rc = [%d]\n", __FUNCTION__, rc);
+ "rc = [%d]\n", __func__, rc);
out:
return rc;
}
return ecryptfs_write_inode_size_to_header(ecryptfs_inode);
}
-int ecryptfs_get_lower_page(struct page **lower_page, struct inode *lower_inode,
- struct file *lower_file,
- unsigned long lower_page_index, int byte_offset,
- int region_bytes)
-{
- int rc = 0;
-
- *lower_page = grab_cache_page(lower_inode->i_mapping, lower_page_index);
- if (!(*lower_page)) {
- rc = -EINVAL;
- ecryptfs_printk(KERN_ERR, "Error attempting to grab "
- "lower page with index [0x%.16x]\n",
- lower_page_index);
- goto out;
- }
- rc = lower_inode->i_mapping->a_ops->prepare_write(lower_file,
- (*lower_page),
- byte_offset,
- region_bytes);
- if (rc) {
- ecryptfs_printk(KERN_ERR, "prepare_write for "
- "lower_page_index = [0x%.16x] failed; rc = "
- "[%d]\n", lower_page_index, rc);
- ecryptfs_release_lower_page(*lower_page);
- (*lower_page) = NULL;
- }
-out:
- return rc;
-}
-
-/**
- * ecryptfs_commit_lower_page
- *
- * Returns zero on success; non-zero on error
- */
-int
-ecryptfs_commit_lower_page(struct page *lower_page, struct inode *lower_inode,
- struct file *lower_file, int byte_offset,
- int region_size)
-{
- int rc = 0;
-
- rc = lower_inode->i_mapping->a_ops->commit_write(
- lower_file, lower_page, byte_offset, region_size);
- if (rc < 0) {
- ecryptfs_printk(KERN_ERR,
- "Error committing write; rc = [%d]\n", rc);
- } else
- rc = 0;
- ecryptfs_release_lower_page(lower_page);
- return rc;
-}
-
-/**
- * ecryptfs_copy_page_to_lower
- *
- * Used for plaintext pass-through; no page index interpolation
- * required.
- */
-int ecryptfs_copy_page_to_lower(struct page *page, struct inode *lower_inode,
- struct file *lower_file)
-{
- int rc = 0;
- struct page *lower_page;
-
- rc = ecryptfs_get_lower_page(&lower_page, lower_inode, lower_file,
- page->index, 0, PAGE_CACHE_SIZE);
- if (rc) {
- ecryptfs_printk(KERN_ERR, "Error attempting to get page "
- "at index [0x%.16x]\n", page->index);
- goto out;
- }
- /* TODO: aops */
- memcpy((char *)page_address(lower_page), page_address(page),
- PAGE_CACHE_SIZE);
- rc = ecryptfs_commit_lower_page(lower_page, lower_inode, lower_file,
- 0, PAGE_CACHE_SIZE);
- if (rc)
- ecryptfs_printk(KERN_ERR, "Error attempting to commit page "
- "at index [0x%.16x]\n", page->index);
-out:
- return rc;
-}
-
/**
* ecryptfs_commit_write
* @file: The eCryptfs file object
return rc;
}
-/**
- * ecryptfs_write_zeros
- * @file: The ecryptfs file
- * @index: The index in which we are writing
- * @start: The position after the last block of data
- * @num_zeros: The number of zeros to write
- *
- * Write a specified number of zero's to a page.
- *
- * (start + num_zeros) must be less than or equal to PAGE_CACHE_SIZE
- */
-int
-ecryptfs_write_zeros(struct file *file, pgoff_t index, int start, int num_zeros)
-{
- int rc = 0;
- struct page *tmp_page;
-
- tmp_page = ecryptfs_get1page(file, index);
- if (IS_ERR(tmp_page)) {
- ecryptfs_printk(KERN_ERR, "Error getting page at index "
- "[0x%.16x]\n", index);
- rc = PTR_ERR(tmp_page);
- goto out;
- }
- rc = ecryptfs_prepare_write_no_truncate(file, tmp_page, start,
- (start + num_zeros));
- if (rc) {
- ecryptfs_printk(KERN_ERR, "Error preparing to write zero's "
- "to page at index [0x%.16x]\n",
- index);
- page_cache_release(tmp_page);
- goto out;
- }
- zero_user_page(tmp_page, start, num_zeros, KM_USER0);
- rc = ecryptfs_commit_write(file, tmp_page, start, start + num_zeros);
- if (rc < 0) {
- ecryptfs_printk(KERN_ERR, "Error attempting to write zero's "
- "to remainder of page at index [0x%.16x]\n",
- index);
- page_cache_release(tmp_page);
- goto out;
- }
- rc = 0;
- page_cache_release(tmp_page);
-out:
- return rc;
-}
-
static sector_t ecryptfs_bmap(struct address_space *mapping, sector_t block)
{
int rc = 0;
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff