ecryptfs-devel team mailing list archive

[Eric Sandeen <sandeen@xxxxxxxxxx>]

Tyler Hicks wrote:
> Fixes regression in 8faece5f906725c10e7a1f6caf84452abadbdc7b
> 
> 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.
> 
> Signed-off-by: Tyler Hicks <tyhicks@xxxxxxxxxxxxxxxxxx>
> Cc: Eric Sandeen <sandeen@xxxxxxxxxx>

Looks good, thanks!

Reviewed-by: Eric Sandeen <sandeen@xxxxxxxxxx>

> ---
>  fs/ecryptfs/crypto.c          |    7 ++++---
>  fs/ecryptfs/ecryptfs_kernel.h |    8 ++++++++
>  fs/ecryptfs/inode.c           |    2 +-
>  fs/ecryptfs/mmap.c            |   19 +++++--------------
>  4 files changed, 18 insertions(+), 18 deletions(-)
> 
> diff --git a/fs/ecryptfs/crypto.c b/fs/ecryptfs/crypto.c
> index 7cb0a59..c907f6f 100644
> --- a/fs/ecryptfs/crypto.c
> +++ b/fs/ecryptfs/crypto.c
> @@ -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 =
> diff --git a/fs/ecryptfs/ecryptfs_kernel.h b/fs/ecryptfs/ecryptfs_kernel.h
> index 542f625..8456f70 100644
> --- a/fs/ecryptfs/ecryptfs_kernel.h
> +++ b/fs/ecryptfs/ecryptfs_kernel.h
> @@ -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)
>  {
> diff --git a/fs/ecryptfs/inode.c b/fs/ecryptfs/inode.c
> index 4a430ab..1a73953 100644
> --- a/fs/ecryptfs/inode.c
> +++ b/fs/ecryptfs/inode.c
> @@ -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;
>  
> diff --git a/fs/ecryptfs/mmap.c b/fs/ecryptfs/mmap.c
> index df4ce99..5a30e01 100644
> --- a/fs/ecryptfs/mmap.c
> +++ b/fs/ecryptfs/mmap.c
> @@ -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);