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Commit f4e60e6b authored by Tyler Hicks's avatar Tyler Hicks
Browse files

eCryptfs: Strip metadata in xattr flag in encrypted view 



The ecryptfs_encrypted_view mount option provides a unified way of
viewing encrypted eCryptfs files.  If the metadata is stored in a xattr,
the metadata is moved to the file header when the file is read inside
the eCryptfs mount.  Because of this, we should strip the
ECRYPTFS_METADATA_IN_XATTR flag from the header's flag section.  This
allows eCryptfs to treat the file as an eCryptfs file with a header
at the front.

Reviewed-by: default avatarEric Sandeen <sandeen@redhat.com>
Signed-off-by: default avatarTyler Hicks <tyhicks@linux.vnet.ibm.com>
parent 1984c23f

fs/ecryptfs/crypto.c

+5 −4
Original line number Original line Diff line number Diff line
@@ -1107,8 +1107,8 @@ static void write_ecryptfs_marker(char *page_virt, size_t *written) 
	(*written) = MAGIC_ECRYPTFS_MARKER_SIZE_BYTES;

	(*written) = MAGIC_ECRYPTFS_MARKER_SIZE_BYTES;

}

}





static void

void ecryptfs_write_crypt_stat_flags(char *page_virt,

write_ecryptfs_flags(char *page_virt, struct ecryptfs_crypt_stat *crypt_stat,

				     struct ecryptfs_crypt_stat *crypt_stat,

				     size_t *written)

				     size_t *written)

{

{

	u32 flags = 0;

	u32 flags = 0;
@@ -1290,7 +1290,8 @@ static int ecryptfs_write_headers_virt(char *page_virt, size_t max, 
	offset = ECRYPTFS_FILE_SIZE_BYTES;

	offset = ECRYPTFS_FILE_SIZE_BYTES;

	write_ecryptfs_marker((page_virt + offset), &written);

	write_ecryptfs_marker((page_virt + offset), &written);

	offset += written;

	offset += written;

	write_ecryptfs_flags((page_virt + offset), crypt_stat, &written);

	ecryptfs_write_crypt_stat_flags((page_virt + offset), crypt_stat,

					&written);

	offset += written;

	offset += written;

	ecryptfs_write_header_metadata((page_virt + offset), crypt_stat,

	ecryptfs_write_header_metadata((page_virt + offset), crypt_stat,

				       &written);

				       &written);

fs/ecryptfs/ecryptfs_kernel.h

+3 −0
Original line number Original line Diff line number Diff line
@@ -659,6 +659,9 @@ int ecryptfs_decrypt_page(struct page *page); 
int ecryptfs_write_metadata(struct dentry *ecryptfs_dentry);

int ecryptfs_write_metadata(struct dentry *ecryptfs_dentry);

int ecryptfs_read_metadata(struct dentry *ecryptfs_dentry);

int ecryptfs_read_metadata(struct dentry *ecryptfs_dentry);

int ecryptfs_new_file_context(struct dentry *ecryptfs_dentry);

int ecryptfs_new_file_context(struct dentry *ecryptfs_dentry);

void ecryptfs_write_crypt_stat_flags(char *page_virt,

				     struct ecryptfs_crypt_stat *crypt_stat,

				     size_t *written);

int ecryptfs_read_and_validate_header_region(char *data,

int ecryptfs_read_and_validate_header_region(char *data,

					     struct inode *ecryptfs_inode);

					     struct inode *ecryptfs_inode);

int ecryptfs_read_and_validate_xattr_region(char *page_virt,

int ecryptfs_read_and_validate_xattr_region(char *page_virt,

fs/ecryptfs/mmap.c

+14 −0
Original line number Original line Diff line number Diff line
@@ -82,6 +82,19 @@ static int ecryptfs_writepage(struct page *page, struct writeback_control *wbc) 
	return rc;

	return rc;

}

}





static void strip_xattr_flag(char *page_virt,

			     struct ecryptfs_crypt_stat *crypt_stat)

{

	if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR) {

		size_t written;



		crypt_stat->flags &= ~ECRYPTFS_METADATA_IN_XATTR;

		ecryptfs_write_crypt_stat_flags(page_virt, crypt_stat,

						&written);

		crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;

	}

}



/**

/**

 *   Header Extent:

 *   Header Extent:

 *     Octets 0-7:        Unencrypted file size (big-endian)

 *     Octets 0-7:        Unencrypted file size (big-endian)
@@ -136,6 +149,7 @@ ecryptfs_copy_up_encrypted_with_header(struct page *page, 




				rc = ecryptfs_read_xattr_region(

				rc = ecryptfs_read_xattr_region(

					page_virt, page->mapping->host);

					page_virt, page->mapping->host);

				strip_xattr_flag(page_virt + 16, crypt_stat);

				ecryptfs_write_header_metadata(page_virt + 20,

				ecryptfs_write_header_metadata(page_virt + 20,

							       crypt_stat,

							       crypt_stat,

							       &written);

							       &written);