auth: mech-scram - Restructure message parsing in parse_scram_client_first().

diff --git a/src/auth/mech-scram.c b/src/auth/mech-scram.c
index a90d39608d58e8f4e12ffefd52a1cfb9bc12f097..b88d2ab666c35bd0bb3230c03f5a9af266b81a1c 100644 (file)
--- a/src/auth/mech-scram.c
+++ b/src/auth/mech-scram.c
@@ -126,18 +126,40 @@ parse_scram_client_first(struct scram_auth_request *request,
                         const unsigned char *data, size_t size,
                         const char **error_r)
 {
-       const char *const *fields, *login_username = NULL;
-       const char *gs2_cbind_flag, *authzid, *username, *nonce;
+       const char *login_username = NULL;
+       const char *data_cstr, *p;
+       const char *gs2_cbind_flag, *authzid;
+       const char *cfm_bare, *username, *nonce;
+       const char *const *fields;
+
+       data_cstr = t_strndup(data, size);
+
+       p = strchr(data_cstr, ',');
+       if (p == NULL) {
+               *error_r = "Invalid initial client message: "
+                       "Missing first ',' in GS2 header";
+               return FALSE;
+       }
+       gs2_cbind_flag = t_strdup_until(data_cstr, p);
+       data_cstr = p + 1;
 
-       fields = t_strsplit(t_strndup(data, size), ",");
-       if (str_array_length(fields) < 4) {
-               *error_r = "Invalid initial client message";
+       p = strchr(data_cstr, ',');
+       if (p == NULL) {
+               *error_r = "Invalid initial client message: "
+                       "Missing second ',' in GS2 header";
+               return FALSE;
+       }
+       authzid = t_strdup_until(data_cstr, p);
+       cfm_bare = p + 1;
+
+       fields = t_strsplit(cfm_bare, ",");
+       if (str_array_length(fields) < 2) {
+               *error_r = "Invalid initial client message: "
+                       "Missing nonce field";
                return FALSE;
        }
-       gs2_cbind_flag = fields[0];
-       authzid = fields[1];
-       username = fields[2];
-       nonce = fields[3];
+       username = fields[0];
+       nonce = fields[1];
 
        /* Order of fields is fixed:
 
@@ -219,10 +241,7 @@ parse_scram_client_first(struct scram_auth_request *request,
                return FALSE;
        }
 
-       /* This works only without channel binding support,
-          otherwise the GS2 header doesn't have a fixed length */
-       request->client_first_message_bare =
-               p_strndup(request->pool, data + 3, size - 3);
+       request->client_first_message_bare = p_strdup(request->pool, cfm_bare);
        return TRUE;
 }