Support hashed usernames per RFC7616.

* src/ne_auth.c (struct auth_challenge): Add userhash field.
  (auth_session): Likewise.
  (digest_challenge): Calculate userhash if challenge
  used userhash=true.
  (request_digest): Use userhash, userhash=true as appropriate.
  (auth_challenge): Parse userhash parameter.
  (clean_session): Free userhash.

* test/auth.c (verify_digest_header, make_digest_header,
  serve_digest): Add userhash support.
  (digest): Test for userhash=true and userhash=false.

2 files changed, 61 insertions, 3 deletions

diff --git a/src/ne_auth.c b/src/ne_auth.c
index 9c3321a..a9580e2 100644
--- a/src/ne_auth.c
+++ b/src/ne_auth.c
@@ -122,6 +122,7 @@ struct auth_challenge {
     unsigned int stale; /* if stale=true */
     unsigned int got_qop; /* we were given a qop directive */
     unsigned int qop_auth; /* "auth" token in qop attrib */
+    unsigned int userhash; /* got userhash=true */
     auth_algorithm alg;
     struct auth_challenge *next;
 };
@@ -194,6 +195,7 @@ typedef struct {
     char *opaque;
     char **domains; /* list of paths given as domain. */
     size_t ndomains; /* size of domains array */
+    char *userhash;
     auth_qop qop;
     auth_algorithm alg;
     unsigned int nonce_count;
@@ -277,8 +279,9 @@ static void clean_session(auth_session *sess)
     if (sess->cnonce) ne_free(sess->cnonce);
     if (sess->opaque) ne_free(sess->opaque);
     if (sess->realm) ne_free(sess->realm);
+    if (sess->userhash) ne_free(sess->userhash);
     sess->realm = sess->basic = sess->cnonce = sess->nonce =
-        sess->opaque = NULL;
+        sess->opaque = sess->userhash = NULL;
     if (sess->stored_rdig) {
         ne_md5_destroy_ctx(sess->stored_rdig);
         sess->stored_rdig = NULL;
@@ -840,6 +843,21 @@ static int digest_challenge(auth_session *sess, int attempt,
             /* Failed to get credentials */
             return -1;
         }
+
+        /* Calculate userhash for this (realm, username) if required.
+         * https://tools.ietf.org/html/rfc7616#section-3.4.4 */
+        if (parms->userhash) {
+            struct ne_md5_ctx *tmp;
+            char digest[33];
+
+            tmp = ne_md5_create_ctx();
+            ne_md5_process_bytes(sess->username, strlen(sess->username), tmp);
+            ne_md5_process_bytes(":", 1, tmp);
+            ne_md5_process_bytes(sess->realm, strlen(sess->realm), tmp);
+            ne_md5_finish_ascii(tmp, digest);
+
+            sess->userhash = ne_strdup(digest);
+        }
     }
     else {
         /* Stale challenge: accept a new nonce or opaque. */
@@ -998,7 +1016,8 @@ static char *request_digest(auth_session *sess, struct auth_request *req)
     ret = ne_buffer_create();
 
     ne_buffer_concat(ret, 
-		     "Digest username=\"", sess->username, "\", "
+                     "Digest username=\"",
+                     sess->userhash ? sess->userhash : sess->username, "\", "
 		     "realm=\"", sess->realm, "\", "
 		     "nonce=\"", sess->nonce, "\", "
 		     "uri=\"", req->uri, "\", "
@@ -1016,6 +1035,9 @@ static char *request_digest(auth_session *sess, struct auth_request *req)
 			 "nc=", nc_value, ", "
 			 "qop=\"", qop_value, "\"", NULL);
     }
+    if (sess->userhash) {
+        ne_buffer_czappend(ret, ", userhash=true");
+    }
 
     ne_buffer_zappend(ret, "\r\n");
 
@@ -1390,6 +1412,9 @@ static int auth_challenge(auth_session *sess, int attempt,
         else if (ne_strcasecmp(key, "domain") == 0) {
             chall->domain = val;
         }
+        else if (ne_strcasecmp(key, "userhash") == 0) {
+            chall->userhash = strcmp(val, "true") == 0;
+        }
     }
     
     sess->protocol = NULL;
diff --git a/test/auth.c b/test/auth.c
index 3055165..bdd1867 100644
--- a/test/auth.c
+++ b/test/auth.c
@@ -380,6 +380,8 @@ static void dup_header(char *header)
 #define PARM_NEXTNONCE (0x0002)
 #define PARM_RFC2617   (0x0004)
 #define PARM_AINFO     (0x0008)
+#define PARM_USERHASH  (0x0010) /* userhash=true */
+#define PARM_UHFALSE   (0x0020) /* userhash=false */
 
 struct digest_parms {
     const char *realm, *nonce, *opaque, *domain;
@@ -409,9 +411,11 @@ struct digest_parms {
 struct digest_state {
     const char *realm, *nonce, *uri, *username, *password, *algorithm, *qop,
         *method, *opaque;
+    char userhash[33];
     char *cnonce, *digest, *ncval;
     long nc;
     int count;
+    int uhash_bool;
 };
 
 #ifdef HAVE_OPENSSL11
@@ -580,6 +584,9 @@ static int verify_digest_header(struct digest_state *state,
         else if (ne_strcasecmp(name, "response") == 0) {
             state->digest = ne_strdup(val);
         }
+        else if (ne_strcasecmp(name, "userhash") == 0 ) {
+            newstate.uhash_bool = strcmp(val, "true") == 0;
+        }
     }
 
     ONN("cnonce param missing or short for 2617-style auth",
@@ -587,8 +594,18 @@ static int verify_digest_header(struct digest_state *state,
         && (newstate.cnonce == NULL
             || strlen(newstate.cnonce) < 32));
 
+    if (parms->flags & PARM_USERHASH) {
+        ONN("userhash missing", !newstate.uhash_bool);
+
+        ONCMP(state->userhash, newstate.username,
+              "Digest username (userhash) field", "userhash");
+    }
+    else {
+        ONN("unexpected userhash=true sent", newstate.uhash_bool);
+        DIGCMP(username);
+    }
+
     DIGCMP(realm);
-    DIGCMP(username);
     if (!parms->domain)
         DIGCMP(uri);
     DIGCMP(nonce);
@@ -698,6 +715,13 @@ static char *make_digest_header(struct digest_state *state,
         ne_buffer_concat(buf, "domain=\"", parms->domain, "\", ", NULL);
     }
 
+    if (parms->flags & PARM_USERHASH) {
+        ne_buffer_czappend(buf, "userhash=true, ");
+    }
+    else if (parms->flags & PARM_UHFALSE) {
+        ne_buffer_czappend(buf, "userhash=false, ");
+    }
+
     if (parms->failure == fail_req0_stale
         || parms->failure == fail_req0_2069_stale
         || parms->stale == parms->num_requests) {
@@ -737,6 +761,10 @@ static int serve_digest(ne_socket *sock, void *userdata)
     }
     state.qop = "auth";
 
+    if (parms->flags & PARM_USERHASH) {
+        hash(parms, state.userhash, username, ":", parms->realm, NULL);
+    }
+
     state.cnonce = state.digest = state.ncval = NULL;
 
     parms->num_requests += parms->stale ? 1 : 0;
@@ -871,6 +899,11 @@ static int digest(void)
         /* 2069 + stale */
         { "WallyWorld", "this-is-a-nonce", NULL, NULL, ALG_MD5, PARM_AINFO, 3, 2, fail_not },
 
+        /* RFC 7616-style */
+        { "WallyWorld", "new-day-new-nonce", "new-opaque", NULL, ALG_MD5, PARM_RFC2617 | PARM_USERHASH, 1, 0, fail_not },
+        /* ... userhash=false */
+        { "WallyWorld", "just-another-nonce", "new-opaque", NULL, ALG_MD5, PARM_RFC2617 | PARM_UHFALSE, 1, 0, fail_not },
+
         /* RFC 2069-style */ 
         { "WallyWorld", "lah-di-da-di-dah", NULL, NULL, ALG_MD5, 0, 1, 0, fail_not },
         { "WallyWorld", "fee-fi-fo-fum", "opaque-string", NULL, ALG_MD5, 0, 1, 0, fail_not },