Commit 157f1071 authored by Tyler Hicks's avatar Tyler Hicks
Browse files

eCryptfs: Fix metadata in xattr feature regression 



Fixes regression in 8faece5f

When using the ecryptfs_xattr_metadata mount option, eCryptfs stores the
metadata (normally stored at the front of the file) in the user.ecryptfs
xattr.  This causes ecryptfs_crypt_stat.num_header_bytes_at_front to be
0, since there is no header data at the front of the file.  This results
in too much memory being requested and ENOMEM being returned from
ecryptfs_write_metadata().

This patch fixes the problem by using the num_header_bytes_at_front
variable for specifying the max size of the metadata, despite whether it
is stored in the header or xattr.

Reviewed-by: default avatarEric Sandeen <sandeen@redhat.com>
Signed-off-by: default avatarTyler Hicks <tyhicks@linux.vnet.ibm.com>
parent 220bf991

fs/ecryptfs/crypto.c

+4 −3
Original line number Diff line number Diff line
@@ -381,8 +381,8 @@ out: 
static void ecryptfs_lower_offset_for_extent(loff_t *offset, loff_t extent_num,

					     struct ecryptfs_crypt_stat *crypt_stat)

{

	(*offset) = (crypt_stat->num_header_bytes_at_front

		     + (crypt_stat->extent_size * extent_num));

	(*offset) = ecryptfs_lower_header_size(crypt_stat)

		    + (crypt_stat->extent_size * extent_num);

}



/**
@@ -834,7 +834,8 @@ void ecryptfs_set_default_sizes(struct ecryptfs_crypt_stat *crypt_stat) 
	set_extent_mask_and_shift(crypt_stat);

	crypt_stat->iv_bytes = ECRYPTFS_DEFAULT_IV_BYTES;

	if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)

		crypt_stat->num_header_bytes_at_front = 0;

		crypt_stat->num_header_bytes_at_front =

					ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;

	else {

		if (PAGE_CACHE_SIZE <= ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE)

			crypt_stat->num_header_bytes_at_front =

fs/ecryptfs/ecryptfs_kernel.h

+8 −0
Original line number Diff line number Diff line
@@ -464,6 +464,14 @@ struct ecryptfs_daemon { 


extern struct mutex ecryptfs_daemon_hash_mux;



static inline size_t

ecryptfs_lower_header_size(struct ecryptfs_crypt_stat *crypt_stat)

{

	if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)

		return 0;

	return crypt_stat->num_header_bytes_at_front;

}



static inline struct ecryptfs_file_info *

ecryptfs_file_to_private(struct file *file)

{

fs/ecryptfs/inode.c

+1 −1
Original line number Diff line number Diff line
@@ -768,7 +768,7 @@ upper_size_to_lower_size(struct ecryptfs_crypt_stat *crypt_stat, 
{

	loff_t lower_size;



	lower_size = crypt_stat->num_header_bytes_at_front;

	lower_size = ecryptfs_lower_header_size(crypt_stat);

	if (upper_size != 0) {

		loff_t num_extents;

fs/ecryptfs/mmap.c

+5 −14
Original line number Diff line number Diff line
@@ -97,19 +97,6 @@ out: 
 *                        (big-endian)

 *     Octet  26:         Begin RFC 2440 authentication token packet set

 */

static void set_header_info(char *page_virt,

			    struct ecryptfs_crypt_stat *crypt_stat)

{

	size_t written;

	size_t save_num_header_bytes_at_front =

		crypt_stat->num_header_bytes_at_front;



	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_bytes_at_front =

		save_num_header_bytes_at_front;

}



/**

 * ecryptfs_copy_up_encrypted_with_header
@@ -146,9 +133,13 @@ ecryptfs_copy_up_encrypted_with_header(struct page *page, 
			memset(page_virt, 0, PAGE_CACHE_SIZE);

			/* TODO: Support more than one header extent */

			if (view_extent_num == 0) {

				size_t written;



				rc = ecryptfs_read_xattr_region(

					page_virt, page->mapping->host);

				set_header_info(page_virt, crypt_stat);

				ecryptfs_write_header_metadata(page_virt + 20,

							       crypt_stat,

							       &written);

			}

			kunmap_atomic(page_virt, KM_USER0);

			flush_dcache_page(page);

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