fs-verity: rename fsverity_signed_digest to fsverity_formatted_digest

The name "struct fsverity_signed_digest" is causing confusion because it
isn't actually a signed digest, but rather it's the way that the digest
is formatted in order to be signed.  Rename it to
"struct fsverity_formatted_digest" to prevent this confusion.

Also update the struct's comment to clarify that it's specific to the
built-in signature verification support and isn't a requirement for all
fs-verity users.

I'll be renaming this struct in fsverity-utils too.

Acked-by: Luca Boccassi <luca.boccassi@microsoft.com>
Link: https://lore.kernel.org/r/20201113211918.71883-3-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
This commit is contained in:
Eric Biggers 2020-11-13 13:19:16 -08:00
parent 7bf765dd84
commit 9e90f30e78
3 changed files with 14 additions and 7 deletions

View File

@ -372,7 +372,7 @@ kernel. Specifically, it adds support for:
File measurements must be signed in the following format, which is
similar to the structure used by `FS_IOC_MEASURE_VERITY`_::
struct fsverity_signed_digest {
struct fsverity_formatted_digest {
char magic[8]; /* must be "FSVerity" */
__le16 digest_algorithm;
__le16 digest_size;

View File

@ -101,12 +101,19 @@ struct fsverity_descriptor {
sizeof(struct fsverity_descriptor))
/*
* Format in which verity file measurements are signed. This is the same as
* 'struct fsverity_digest', except here some magic bytes are prepended to
* provide some context about what is being signed in case the same key is used
* for non-fsverity purposes, and here the fields have fixed endianness.
* Format in which verity file measurements are signed in built-in signatures.
* This is the same as 'struct fsverity_digest', except here some magic bytes
* are prepended to provide some context about what is being signed in case the
* same key is used for non-fsverity purposes, and here the fields have fixed
* endianness.
*
* This struct is specific to the built-in signature verification support, which
* is optional. fs-verity users may also verify signatures in userspace, in
* which case userspace is responsible for deciding on what bytes are signed.
* This struct may still be used, but it doesn't have to be. For example,
* userspace could instead use a string like "sha256:$digest_as_hex_string".
*/
struct fsverity_signed_digest {
struct fsverity_formatted_digest {
char magic[8]; /* must be "FSVerity" */
__le16 digest_algorithm;
__le16 digest_size;

View File

@ -44,7 +44,7 @@ int fsverity_verify_signature(const struct fsverity_info *vi,
const struct inode *inode = vi->inode;
const struct fsverity_hash_alg *hash_alg = vi->tree_params.hash_alg;
const u32 sig_size = le32_to_cpu(desc->sig_size);
struct fsverity_signed_digest *d;
struct fsverity_formatted_digest *d;
int err;
if (sig_size == 0) {