[7/7] cmd_sign: fsverity_cmd_sign() into two functions

Commit Message

Jes Sorensen Feb. 11, 2020, midnight UTC

From: Jes Sorensen <[e-mail]>

This splits cmd_sign() into a gen_digest() and a sign_digest()
function, and fixes fsverity.c to use them appropriately.
---
 cmd_sign.c | 50 +++++++++++++++++++++++++++++++++-----------------
 fsverity.c |  8 ++++++--
 fsverity.h | 13 ++++++++-----
 3 files changed, 47 insertions(+), 24 deletions(-)

Patch

diff --git a/cmd_sign.c b/cmd_sign.c
index a0bd168..ba68243 100644
--- a/cmd_sign.c
+++ b/cmd_sign.c
@@ -481,12 +481,11 @@  out:
 	return ok;
 }
 
-/* Sign a file for fs-verity by computing its measurement, then signing it. */
-int fsverity_cmd_sign(char *filename, const struct fsverity_hash_alg *hash_alg,
-		      u32 block_size, u8 *salt, u32 salt_size,
-		      const char *keyfile, const char *certfile,
-		      struct fsverity_signed_digest **retdigest,
-		      u8 **sig, u32 *sig_size)
+/* Generate the fsverity digest computing its measurement. */
+int fsverity_cmd_gen_digest(char *filename,
+			    const struct fsverity_hash_alg *hash_alg,
+			    u32 block_size, u8 *salt, u32 salt_size,
+			    struct fsverity_signed_digest **retdigest)
 {
 	struct fsverity_signed_digest *digest = NULL;
 	int status;
@@ -499,13 +498,6 @@  int fsverity_cmd_sign(char *filename, const struct fsverity_hash_alg *hash_alg,
 	if (block_size == 0)
 		block_size = fsverity_get_default_block_size();
 
-	if (keyfile == NULL) {
-		status = -EINVAL;
-		goto out;
-	}
-	if (certfile == NULL)
-		certfile = keyfile;
-
 	digest = xzalloc(sizeof(*digest) + hash_alg->digest_size);
 	memcpy(digest->magic, "FSVerity", 8);
 	digest->digest_algorithm = cpu_to_le16(hash_alg - fsverity_hash_algs);
@@ -515,10 +507,6 @@  int fsverity_cmd_sign(char *filename, const struct fsverity_hash_alg *hash_alg,
 				      salt, salt_size, digest->digest))
 		goto out_err;
 
-	if (!sign_data(digest, sizeof(*digest) + hash_alg->digest_size,
-		       keyfile, certfile, hash_alg, sig, sig_size))
-		goto out_err;
-
 	*retdigest = digest;
 	status = 0;
 out:
@@ -529,3 +517,31 @@  out_err:
 	goto out;
 
 }
+
+/* Sign a pre-generated fsverity_signed_digest structure */
+int fsverity_cmd_sign_digest(struct fsverity_signed_digest *digest,
+			     const struct fsverity_hash_alg *hash_alg,
+			     const char *keyfile, const char *certfile,
+			     u8 **sig, u32 *sig_size)
+{
+	int status;
+
+	if (keyfile == NULL) {
+		status = -EINVAL;
+		goto out;
+	}
+	if (certfile == NULL)
+		certfile = keyfile;
+
+	if (!sign_data(digest, sizeof(*digest) + hash_alg->digest_size,
+		       keyfile, certfile, hash_alg, sig, sig_size))
+		goto out_err;
+
+	status = 0;
+ out:
+	return status;
+
+ out_err:
+	status = 1;
+	goto out;
+}
diff --git a/fsverity.c b/fsverity.c
index 45bf0cc..3fcafcb 100644
--- a/fsverity.c
+++ b/fsverity.c
@@ -188,8 +188,12 @@  int wrap_cmd_sign(const struct fsverity_command *cmd, int argc, char *argv[])
 	if (argc != 2)
 		goto out_usage;
 
-	status = fsverity_cmd_sign(argv[0], hash_alg, block_size, salt, salt_size,
-				   keyfile, certfile, &digest, &sig, &sig_size);
+	status = fsverity_cmd_gen_digest(argv[0], hash_alg, block_size,
+					 salt, salt_size, &digest);
+	if (status)
+		goto out_usage;
+	status = fsverity_cmd_sign_digest(digest, hash_alg, keyfile, certfile,
+					  &sig, &sig_size);
 	if (status == -EINVAL)
 		goto out_usage;
 	if (status != 0)
diff --git a/fsverity.h b/fsverity.h
index bb2f337..695bdac 100644
--- a/fsverity.h
+++ b/fsverity.h
@@ -26,10 +26,13 @@  u32 fsverity_get_default_block_size(void);
 
 int fsverity_cmd_enable(char *filename, struct fsverity_enable_arg *arg);
 int fsverity_cmd_measure(char *filename, struct fsverity_digest *d);
-int fsverity_cmd_sign(char *filename, const struct fsverity_hash_alg *hash_alg,
-		      u32 block_size, u8 *salt, u32 salt_size,
-		      const char *keyfile, const char *certfile,
-		      struct fsverity_signed_digest **retdigest,
-		      u8 **sig, u32 *sig_size);
+int fsverity_cmd_gen_digest(char *filename,
+			    const struct fsverity_hash_alg *hash_alg,
+			    u32 block_size, u8 *salt, u32 salt_size,
+			    struct fsverity_signed_digest **retdigest);
+int fsverity_cmd_sign_digest(struct fsverity_signed_digest *digest,
+			     const struct fsverity_hash_alg *hash_alg,
+			     const char *keyfile, const char *certfile,
+			     u8 **sig, u32 *sig_size);
 
 #endif /* COMMANDS_H */