MINOR: jws: support HMAC in jws_b64_protected(), make nonce optional

This adds support for HMAC algorithms in jws_b64_protected(), but also
makes nonce field optional, because it isn't needed in some cases where
HMAC is used, primarily ACME EAB requires that nonce field must not
exist.

diff --git a/src/jws.c b/src/jws.c
index e4ea30de695c29f44e52a84dad95cd1e84a4979c..31808a4e30566143e14197518dff12daf16cc6ef 100644 (file)
--- a/src/jws.c
+++ b/src/jws.c
@@ -219,6 +219,7 @@ size_t EVP_PKEY_to_pub_jwk(EVP_PKEY *pkey, char *dst, size_t dsize)
 /*
  * Generate the JWS payload and converts it to base64url.
  * Use either <kid> or <jwk>, but won't use both
+ * <nonce> is optional.
  *
  * Return the size of the data or 0
  */
@@ -226,13 +227,14 @@ size_t EVP_PKEY_to_pub_jwk(EVP_PKEY *pkey, char *dst, size_t dsize)
 size_t jws_b64_protected(enum jwt_alg alg, char *kid, char *jwk, char *nonce, char *url,
                          char *dst, size_t dsize)
 {
-       char *acc;
-       char *acctype;
        int ret = 0;
        struct buffer *json = NULL;
        const char *algstr;
 
        switch (alg) {
+               case JWS_ALG_HS256: algstr = "HS256"; break;
+               case JWS_ALG_HS384: algstr = "HS384"; break;
+               case JWS_ALG_HS512: algstr = "HS512"; break;
                case JWS_ALG_RS256: algstr = "RS256"; break;
                case JWS_ALG_RS384: algstr = "RS384"; break;
                case JWS_ALG_RS512: algstr = "RS512"; break;
@@ -246,24 +248,16 @@ size_t jws_b64_protected(enum jwt_alg alg, char *kid, char *jwk, char *nonce, ch
        if ((json = alloc_trash_chunk()) == NULL)
                goto out;
 
-       /* kid or jwk ? */
-       acc = kid ? kid : jwk;
-       acctype = kid ? "kid" : "jwk";
-
-       ret = snprintf(json->area, json->size, "{\n"
-                       "    \"alg\": \"%s\",\n"
-                       "    \"%s\":  %s%s%s,\n"
-                       "    \"nonce\":   \"%s\",\n"
-                       "    \"url\":   \"%s\"\n"
-                       "}\n",
-                       algstr, acctype, kid ? "\"" : "", acc, kid ? "\"" : "", nonce, url);
-       if (ret >= json->size) {
-               ret = 0;
-               goto out;
-       }
-
-
-       json->data = ret;
+       chunk_appendf(json, "{");
+       if (kid)
+               chunk_appendf(json, "\"kid\": \"%s\",", kid);
+       else
+               chunk_appendf(json, "\"jwk\": %s,", jwk);
+       if (nonce)
+               chunk_appendf(json, "\"nonce\": \"%s\",", nonce);
+       chunk_appendf(json, "\"alg\": \"%s\",", algstr);
+       chunk_appendf(json, "\"url\": \"%s\"", url);
+       chunk_appendf(json, "}");
 
        ret = a2base64url(json->area, json->data, dst, dsize);
 out: