rots-utils: fix const warning

source/sign.c

@@ -95,6 +95,7 @@ static int sign(const char *image, const char *name, const char *digest_name,
 	unsigned char *sig;
 	EVP_MD_CTX *ctx = NULL;
 	size_t nbytes, size, sig_len = 0;
+	int ret;
 
 	if (!image || !digest_name || !key)
 		return -1;
@@ -147,11 +148,15 @@ static int sign(const char *image, const char *name, const char *digest_name,
 	if (fseek(fp, 0, SEEK_END) < 0)
 		goto err_free_sig;
 
-	sig_hdr.name = name;
-	sig_hdr.digest = digest_name;
+	sig_hdr.name = strdup(name);
+	sig_hdr.digest = strdup(digest_name);
 	sig_hdr.size = sig_len;
 
-	if (rots_write_sig_hdr(fp, &sig_hdr) < 0)
+	ret = rots_write_sig_hdr(fp, &sig_hdr);
+	free(sig_hdr.digest);
+	free(sig_hdr.name);
+
+	if (ret < 0)
 		goto err_free_sig;
 
 	if (fwrite(sig, sizeof *sig, sig_len, fp) < sig_len)