fs-verity: rename "file measurement" to "file digest"

I originally chose the name "file measurement" to refer to the fs-verity
file digest to avoid confusion with traditional full-file digests or
with the bare root hash of the Merkle tree.

But the name "file measurement" hasn't caught on, and usually people are
calling it something else, usually the "file digest".  E.g. see
"struct fsverity_digest" and "struct fsverity_formatted_digest", the
libfsverity_compute_digest() and libfsverity_sign_digest() functions in
libfsverity, and the "fsverity digest" command.

Having multiple names for the same thing is always confusing.

So to hopefully avoid confusion in the future, rename
"fs-verity file measurement" to "fs-verity file digest".

This leaves FS_IOC_MEASURE_VERITY as the only reference to "measure" in
the kernel, which makes some amount of sense since the ioctl is actively
"measuring" the file.

I'll be renaming this in fsverity-utils too (though similarly the
'fsverity measure' command, which is a wrapper for
FS_IOC_MEASURE_VERITY, will stay).

Acked-by: Luca Boccassi <luca.boccassi@microsoft.com>
Link: https://lore.kernel.org/r/20201113211918.71883-4-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>

1 files changed, 11 insertions, 11 deletions

diff --git a/fs/verity/open.c b/fs/verity/open.c
index a28d5be78a09..228d0eca3e2e 100644
--- a/fs/verity/open.c
+++ b/fs/verity/open.c
@@ -124,18 +124,18 @@ out_err:
 }
 
 /*
- * Compute the file measurement by hashing the fsverity_descriptor excluding the
+ * Compute the file digest by hashing the fsverity_descriptor excluding the
  * signature and with the sig_size field set to 0.
  */
-static int compute_file_measurement(struct fsverity_hash_alg *hash_alg,
-				    struct fsverity_descriptor *desc,
-				    u8 *measurement)
+static int compute_file_digest(struct fsverity_hash_alg *hash_alg,
+			       struct fsverity_descriptor *desc,
+			       u8 *file_digest)
 {
 	__le32 sig_size = desc->sig_size;
 	int err;
 
 	desc->sig_size = 0;
-	err = fsverity_hash_buffer(hash_alg, desc, sizeof(*desc), measurement);
+	err = fsverity_hash_buffer(hash_alg, desc, sizeof(*desc), file_digest);
 	desc->sig_size = sig_size;
 
 	return err;
@@ -199,15 +199,15 @@ struct fsverity_info *fsverity_create_info(const struct inode *inode,
 
 	memcpy(vi->root_hash, desc->root_hash, vi->tree_params.digest_size);
 
-	err = compute_file_measurement(vi->tree_params.hash_alg, desc,
-				       vi->measurement);
+	err = compute_file_digest(vi->tree_params.hash_alg, desc,
+				  vi->file_digest);
 	if (err) {
-		fsverity_err(inode, "Error %d computing file measurement", err);
+		fsverity_err(inode, "Error %d computing file digest", err);
 		goto out;
 	}
-	pr_debug("Computed file measurement: %s:%*phN\n",
+	pr_debug("Computed file digest: %s:%*phN\n",
 		 vi->tree_params.hash_alg->name,
-		 vi->tree_params.digest_size, vi->measurement);
+		 vi->tree_params.digest_size, vi->file_digest);
 
 	err = fsverity_verify_signature(vi, desc, desc_size);
 out:
@@ -354,7 +354,7 @@ int __init fsverity_init_info_cache(void)
 {
 	fsverity_info_cachep = KMEM_CACHE_USERCOPY(fsverity_info,
 						   SLAB_RECLAIM_ACCOUNT,
-						   measurement);
+						   file_digest);
 	if (!fsverity_info_cachep)
 		return -ENOMEM;
 	return 0;