Exemple #1
0
/**
 * ecryptfs_readpage
 * @file: An eCryptfs file
 * @page: Page from eCryptfs inode mapping into which to stick the read data
 *
 * Read in a page, decrypting if necessary.
 *
 * Returns zero on success; non-zero on error.
 */
static int ecryptfs_readpage(struct file *file, struct page *page)
{
	struct ecryptfs_crypt_stat *crypt_stat =
		&ecryptfs_inode_to_private(page->mapping->host)->crypt_stat;
	int rc = 0;

	/* printk("ecryptfs: read page %lu\n", (unsigned long)(page->index)); */
	/* dump_stack(); */

	if (!crypt_stat
	    || !(crypt_stat->flags & ECRYPTFS_ENCRYPTED)
	    || (crypt_stat->flags & ECRYPTFS_NEW_FILE)) {
		ecryptfs_printk(KERN_DEBUG,
				"Passing through unencrypted page\n");
		rc = ecryptfs_read_lower_page_segment(page, page->index, 0,
						      PAGE_CACHE_SIZE,
						      page->mapping->host);
	} 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);
				goto out;
			}

		} else {
			rc = ecryptfs_read_lower_page_segment(
				page, page->index, 0, PAGE_CACHE_SIZE,
				page->mapping->host);
			if (rc) {
				printk(KERN_ERR "Error reading page; rc = "
				       "[%d]\n", rc);
				goto out;
			}
		}
	} else {
		rc = ecryptfs_decrypt_page(page);

		if (rc) {
			ecryptfs_printk(KERN_ERR, "Error decrypting page; "
					"rc = [%d]\n", rc);
			goto out;
		}
	}
out:
	if (rc)
		ClearPageUptodate(page);
	else
		SetPageUptodate(page);
	ecryptfs_printk(KERN_DEBUG, "Unlocking page with index = [0x%.16lx]\n",
			page->index);
	unlock_page(page);
	return rc;
}
Exemple #2
0
/**
 * ecryptfs_readpage
 * @file: An eCryptfs file
 * @page: Page from eCryptfs inode mapping into which to stick the read data
 *
 * Read in a page, decrypting if necessary.
 *
 * Returns zero on success; non-zero on error.
 */
static int ecryptfs_readpage(struct file *file, struct page *page)
{
	struct ecryptfs_crypt_stat *crypt_stat =
		&ecryptfs_inode_to_private(page->mapping->host)->crypt_stat;
#ifdef CONFIG_CRYPTO_DEV_KFIPS
	struct ecryptfs_page_crypt_req *page_crypt_req = NULL;
#endif
	int rc = 0;

	if (!crypt_stat || !(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
		rc = ecryptfs_read_lower_page_segment(page, page->index, 0,
						      PAGE_CACHE_SIZE,
						      page->mapping->host);
	} 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);
				goto out;
			}

		} else {
			rc = ecryptfs_read_lower_page_segment(
				page, page->index, 0, PAGE_CACHE_SIZE,
				page->mapping->host);
			if (rc) {
				printk(KERN_ERR "Error reading page; rc = "
				       "[%d]\n", rc);
				goto out;
			}
		}
	} else {
#ifndef CONFIG_CRYPTO_DEV_KFIPS
		rc = ecryptfs_decrypt_page(page);
		if (rc) {
			ecryptfs_printk(KERN_ERR, "Error decrypting page; "
					"rc = [%d]\n", rc);
#else
		page_crypt_req = ecryptfs_alloc_page_crypt_req(
					page, ecryptfs_readpage_complete);
		if (!page_crypt_req) {
			rc = -ENOMEM;
			ecryptfs_printk(KERN_ERR,
					"Failed to allocate page crypt request "
					"for decryption\n");
#endif
			goto out;
		}
#ifdef CONFIG_CRYPTO_DEV_KFIPS
		ecryptfs_decrypt_page_async(page_crypt_req);
		goto out_async_started;
#endif
	}
out:
#ifndef CONFIG_CRYPTO_DEV_KFIPS
	if (rc)
#else
	if (unlikely(rc))
#endif
		ClearPageUptodate(page);
	else
		SetPageUptodate(page);
	ecryptfs_printk(KERN_DEBUG, "Unlocking page with index = [0x%.16lx]\n",
			page->index);
	unlock_page(page);
#ifdef CONFIG_CRYPTO_DEV_KFIPS
out_async_started:
#endif
	return rc;
}

/**
 * Called with lower inode mutex held.
 */
static int fill_zeros_to_end_of_page(struct page *page, unsigned int to)
{
	struct inode *inode = page->mapping->host;
	int end_byte_in_page;

	if ((i_size_read(inode) / PAGE_CACHE_SIZE) != page->index)
		goto out;
	end_byte_in_page = i_size_read(inode) % PAGE_CACHE_SIZE;
	if (to > end_byte_in_page)
		end_byte_in_page = to;
	zero_user_segment(page, end_byte_in_page, PAGE_CACHE_SIZE);
out:
	return 0;
}

/**
 * ecryptfs_write_begin
 * @file: The eCryptfs file
 * @mapping: The eCryptfs object
 * @pos: The file offset at which to start writing
 * @len: Length of the write
 * @flags: Various flags
 * @pagep: Pointer to return the page
 * @fsdata: Pointer to return fs data (unused)
 *
 * This function must zero any hole we create
 *
 * Returns zero on success; non-zero otherwise
 */
static int ecryptfs_write_begin(struct file *file,
			struct address_space *mapping,
			loff_t pos, unsigned len, unsigned flags,
			struct page **pagep, void **fsdata)
{
	pgoff_t index = pos >> PAGE_CACHE_SHIFT;
	struct page *page;
	loff_t prev_page_end_size;
	int rc = 0;

	page = grab_cache_page_write_begin(mapping, index, flags);
	if (!page)
		return -ENOMEM;
	*pagep = page;

	prev_page_end_size = ((loff_t)index << PAGE_CACHE_SHIFT);
	if (!PageUptodate(page)) {
		struct ecryptfs_crypt_stat *crypt_stat =
			&ecryptfs_inode_to_private(mapping->host)->crypt_stat;

		if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
			rc = ecryptfs_read_lower_page_segment(
				page, index, 0, PAGE_CACHE_SIZE, 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, index, 0, PAGE_CACHE_SIZE,
					mapping->host);
				if (rc) {
					printk(KERN_ERR "%s: Error reading "
					       "page; rc = [%d]\n",
					       __func__, rc);
					ClearPageUptodate(page);
					goto out;
				}
				SetPageUptodate(page);
			}
		} else {
			if (prev_page_end_size
			    >= i_size_read(page->mapping->host)) {
				zero_user(page, 0, PAGE_CACHE_SIZE);
			} 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);
		}
	}
	/* If creating a page or more of holes, zero them out via truncate.
	 * Note, this will increase i_size. */
	if (index != 0) {
		if (prev_page_end_size > i_size_read(page->mapping->host)) {
			rc = ecryptfs_truncate(file->f_path.dentry,
					       prev_page_end_size);
			if (rc) {
				printk(KERN_ERR "%s: Error on attempt to "
				       "truncate to (higher) offset [%lld];"
				       " rc = [%d]\n", __func__,
				       prev_page_end_size, rc);
				goto out;
			}
		}
	}
	/* Writing to a new page, and creating a small hole from start
	 * of page?  Zero it out. */
	if ((i_size_read(mapping->host) == prev_page_end_size)
	    && (pos != 0))
		zero_user(page, 0, PAGE_CACHE_SIZE);
out:
	if (unlikely(rc)) {
		unlock_page(page);
		page_cache_release(page);
		*pagep = NULL;
	}
	return rc;
}
Exemple #3
0
/**
 * 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(struct file *file, struct page *page,
				  unsigned from, unsigned to)
{
	loff_t prev_page_end_size;
	int rc = 0;

	if (!PageUptodate(page)) {
		struct ecryptfs_crypt_stat *crypt_stat =
			&ecryptfs_inode_to_private(
				file->f_dentry->d_inode)->crypt_stat;

		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_dentry,
					       prev_page_end_size);
			if (rc) {
				printk(KERN_ERR "%s: Error on attempt to "
				       "truncate to (higher) offset [%lld];"
				       " rc = [%d]\n", __func__,
				       prev_page_end_size, rc);
				goto out;
			}
		}
	}
	/* 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;
}