inform unapproved servers when we reject their descriptors

svn:r1263

3 files changed, 138 insertions, 76 deletions

diff --git a/src/or/directory.c b/src/or/directory.c
index 6816d5b405..d6be10eff7 100644
--- a/src/or/directory.c
+++ b/src/or/directory.c
@@ -12,8 +12,8 @@ static int directory_handle_command(connection_t *conn);
 extern or_options_t options; /* command-line and config-file options */
 extern int has_fetched_directory;
 
-static char fetchstring[] = "GET / HTTP/1.0\r\n\r\n";
-static char answerstring[] = "HTTP/1.0 200 OK\r\n\r\n";
+#define MAX_HEADERS_SIZE 2048
+#define MAX_BODY_SIZE 500000
 
 /********* END VARIABLES ************/
 
@@ -69,6 +69,7 @@ void directory_initiate_command(routerinfo_t *router, int command) {
 }
 
 static int directory_send_command(connection_t *conn, int command) {
+  char fetchstring[] = "GET / HTTP/1.0\r\n\r\n";
   const char *s;
   char tmp[8192];
 
@@ -94,59 +95,116 @@ static int directory_send_command(connection_t *conn, int command) {
   return 0;
 }
 
+/* Parse "HTTP/1.%d %d%s\r\n".
+ * If it's well-formed, assign *code, point *message to the first
+ * non-space character after code if there is one and message is non-NULL
+ * (else leave it alone), and return 0.
+ * Otherwise, return -1.
+ */
+int parse_http_response(char *headers, int *code, char **message) {
+  int n1, n2;
+  assert(headers && code);
+
+  while(isspace(*headers)) headers++; /* tolerate leading whitespace */
+
+  if(sscanf(headers, "HTTP/1.%d %d", &n1, &n2) < 2 ||
+     (n1 != 0 && n1 != 1) ||
+     (n2 < 100 || n2 >= 600)) {
+    log_fn(LOG_WARN,"Failed to parse header '%s'",headers);
+    return -1;
+  }
+  *code = n2;
+  if(message) {
+    /* XXX should set *message correctly */
+  }
+  return 0;
+}
+
 int connection_dir_process_inbuf(connection_t *conn) {
   char *directory;
-  int directorylen=0;
+  char *headers;
+  int status_code;
 
   assert(conn && conn->type == CONN_TYPE_DIR);
 
   if(conn->inbuf_reached_eof) {
-    switch(conn->state) {
-      case DIR_CONN_STATE_CLIENT_READING_FETCH:
-        /* kill it, but first fetch/process the directory to learn about new routers. */
-        switch(fetch_from_buf_http(conn->inbuf,
-                                   NULL, 0, &directory, MAX_DIR_SIZE)) {
-          case -1: /* overflow */
-            log_fn(LOG_WARN,"'fetch' response too large. Failing.");
-            connection_mark_for_close(conn,0);
-            return -1;
-          case 0:
-            log_fn(LOG_INFO,"'fetch' response not all here, but we're at eof. Closing.");
-            connection_mark_for_close(conn,0);
-            return -1;
-          /* case 1, fall through */
-        }
-        /* XXX check headers, at least make sure returned 2xx */
-        directorylen = strlen(directory);
-        log_fn(LOG_INFO,"Received directory (size %d):\n%s", directorylen, directory);
-        if(directorylen == 0) {
-          log_fn(LOG_INFO,"Empty directory. Ignoring.");
-          free(directory);
-          connection_mark_for_close(conn,0);
-          return 0;
-        }
-        if(router_set_routerlist_from_directory(directory, conn->identity_pkey) < 0){
-          log_fn(LOG_INFO,"...but parsing failed. Ignoring.");
-        } else {
-          log_fn(LOG_INFO,"updated routers.");
-        }
-        has_fetched_directory=1;
-        if(options.ORPort) { /* connect to them all */
-          router_retry_connections();
-        }
-        free(directory);
+    if(conn->state != DIR_CONN_STATE_CLIENT_READING_FETCH &&
+       conn->state != DIR_CONN_STATE_CLIENT_READING_UPLOAD) {
+      log_fn(LOG_INFO,"conn reached eof, not reading. Closing.");
+      connection_close_immediate(conn); /* it was an error; give up on flushing */
+      connection_mark_for_close(conn,0);
+      return -1;
+    }
+
+    switch(fetch_from_buf_http(conn->inbuf,
+                               &headers, MAX_HEADERS_SIZE,
+                               &directory, MAX_DIR_SIZE)) {
+      case -1: /* overflow */
+        log_fn(LOG_WARN,"'fetch' response too large. Failing.");
         connection_mark_for_close(conn,0);
-        return 0;
-      case DIR_CONN_STATE_CLIENT_READING_UPLOAD:
-        /* XXX make sure there's a 200 OK on the buffer */
-        log_fn(LOG_INFO,"eof while reading upload response. Finished.");
+        return -1;
+      case 0:
+        log_fn(LOG_INFO,"'fetch' response not all here, but we're at eof. Closing.");
+        connection_mark_for_close(conn,0);
+        return -1;
+      /* case 1, fall through */
+    }
+
+    if(parse_http_response(headers, &status_code, NULL) < 0) {
+      log_fn(LOG_WARN,"Unparseable headers. Closing.");
+      free(directory); free(headers);
+      connection_mark_for_close(conn,0);
+      return -1;
+    }
+
+    if(conn->state == DIR_CONN_STATE_CLIENT_READING_FETCH) {
+      /* fetch/process the directory to learn about new routers. */
+      int directorylen;
+      directorylen = strlen(directory);
+      log_fn(LOG_INFO,"Received directory (size %d):\n%s", directorylen, directory);
+      if(status_code == 503 || directorylen == 0) {
+        log_fn(LOG_INFO,"Empty directory. Ignoring.");
+        free(directory); free(headers);
         connection_mark_for_close(conn,0);
         return 0;
-      default:
-        log_fn(LOG_INFO,"conn reached eof, not reading. Closing.");
-        connection_close_immediate(conn); /* it was an error; give up on flushing */
+      }
+      if(status_code != 200) {
+        log_fn(LOG_WARN,"Received http status code %d from dirserver. Failing.",
+               status_code);
+        free(directory); free(headers);
         connection_mark_for_close(conn,0);
         return -1;
+      }
+      if(router_set_routerlist_from_directory(directory, conn->identity_pkey) < 0){
+        log_fn(LOG_INFO,"...but parsing failed. Ignoring.");
+      } else {
+        log_fn(LOG_INFO,"updated routers.");
+      }
+      has_fetched_directory=1;
+      if(options.ORPort) { /* connect to them all */
+        router_retry_connections();
+      }
+      free(directory); free(headers);
+      connection_mark_for_close(conn,0);
+      return 0;
+    }
+
+    if(conn->state == DIR_CONN_STATE_CLIENT_READING_UPLOAD) {
+      switch(status_code) {
+        case 200:
+          log_fn(LOG_INFO,"eof (status 200) while reading upload response: finished.");
+          break;
+        case 400:
+          log_fn(LOG_WARN,"http status 400 (bad request) from dirserver. Is your clock skewed?");
+          break;
+        case 403:
+          log_fn(LOG_WARN,"http status 403 (unapproved server) from dirserver. Have you mailed arma your identity fingerprint? Are you using the right key?");
+
+          break;
+      }
+      free(directory); free(headers);
+      connection_mark_for_close(conn,0);
+      return 0;
     }
   }
 
@@ -159,6 +217,11 @@ int connection_dir_process_inbuf(connection_t *conn) {
   return 0;
 }
 
+static char answer200[] = "HTTP/1.0 200 OK\r\n\r\n";
+static char answer400[] = "HTTP/1.0 400 Bad request\r\n\r\n";
+static char answer403[] = "HTTP/1.0 403 Unapproved server\r\n\r\n";
+static char answer503[] = "HTTP/1.0 503 Directory unavailable\r\n\r\n";
+
 static int directory_handle_command_get(connection_t *conn,
                                         char *headers, char *body) {
   size_t dlen;
@@ -171,11 +234,13 @@ static int directory_handle_command_get(connection_t *conn,
 
   if(dlen == 0) {
     log_fn(LOG_WARN,"My directory is empty. Closing.");
-    return -1; /* XXX send some helpful http error code */
+    connection_write_to_buf(answer503, strlen(answer503), conn);
+    conn->state = DIR_CONN_STATE_SERVER_WRITING;
+    return 0;
   }
 
   log_fn(LOG_DEBUG,"Dumping directory to client.");
-  connection_write_to_buf(answerstring, strlen(answerstring), conn);
+  connection_write_to_buf(answer200, strlen(answer200), conn);
   connection_write_to_buf(cp, dlen, conn);
   conn->state = DIR_CONN_STATE_SERVER_WRITING;
   return 0;
@@ -188,12 +253,20 @@ static int directory_handle_command_post(connection_t *conn,
   /* XXX should check url and http version */
   log_fn(LOG_DEBUG,"Received POST command.");
   cp = body;
-  if(dirserv_add_descriptor(&cp) < 0) {
-    log_fn(LOG_WARN,"dirserv_add_descriptor() failed. Dropping.");
-    return -1; /* XXX should write an http failed code */
+  switch(dirserv_add_descriptor(&cp)) {
+    case -1:
+      /* malformed descriptor, or clock is skewed, or something wrong */
+      connection_write_to_buf(answer400, strlen(answer400), conn);
+      break;
+    case 0:
+      /* descriptor was well-formed but server has not been approved */
+      connection_write_to_buf(answer403, strlen(answer403), conn);
+      break;
+    case 1:
+      dirserv_get_directory(&cp); /* rebuild and write to disk */
+      connection_write_to_buf(answer200, strlen(answer200), conn);
+      break;
   }
-  dirserv_get_directory(&cp); /* rebuild and write to disk */
-  connection_write_to_buf(answerstring, strlen(answerstring), conn);
   conn->state = DIR_CONN_STATE_SERVER_WRITING;
   return 0;
 }
@@ -202,9 +275,6 @@ static int directory_handle_command(connection_t *conn) {
   char *headers=NULL, *body=NULL;
   int r;
 
-#define MAX_HEADERS_SIZE 2048
-#define MAX_BODY_SIZE 500000
-
   assert(conn && conn->type == CONN_TYPE_DIR);
 
   switch(fetch_from_buf_http(conn->inbuf,
diff --git a/src/or/dirserv.c b/src/or/dirserv.c
index 3540048faf..0da23a7162 100644
--- a/src/or/dirserv.c
+++ b/src/or/dirserv.c
@@ -182,15 +182,13 @@ dirserv_free_descriptors()
   n_descriptors = 0;
 }
 
-/* Return 0 if descriptor is well-formed; -1 if descriptor is not
- * well-formed.  Update *desc to point after the descriptor if the
+/* Return 1 if descriptor is well-formed and accepted;
+ * 0 if well-formed and server is unapproved;
+ * -1 if not well-formed or if clock is skewed or other error.
+ *
+ * Update *desc to point after the descriptor if the
  * descriptor is well-formed.
  */
-/* XXX down the road perhaps we should return 1 for accepted, 0 for
- * well-formed but rejected, -1 for not-well-formed. So remote servers
- * can know if their submission was accepted and not just whether it
- * was well-formed. ...Or maybe we shouldn't give them that info?
- */
 int
 dirserv_add_descriptor(const char **desc)
 {
@@ -205,7 +203,7 @@ dirserv_add_descriptor(const char **desc)
   start = strstr(*desc, "router ");
   if (!start) {
     log(LOG_WARN, "no descriptor found.");
-    goto err;
+    return -1;
   }
   if ((end = strstr(start+6, "\nrouter "))) {
     ++end; /* Include NL. */
@@ -219,11 +217,11 @@ dirserv_add_descriptor(const char **desc)
 
   /* Check: is the descriptor syntactically valid? */
   ri = router_get_entry_from_string(cp, NULL);
+  tor_free(desc_tmp);
   if (!ri) {
     log(LOG_WARN, "Couldn't parse descriptor");
-    goto err;
+    return -1;
   }
-  tor_free(desc_tmp);
   /* Okay.  Now check whether the fingerprint is recognized. */
   r = dirserv_router_fingerprint_is_known(ri);
   if(r<1) {
@@ -248,7 +246,7 @@ dirserv_add_descriptor(const char **desc)
     log_fn(LOG_WARN, "Publication time for nickname %s is too far in the future; possible clock skew. Not adding", ri->nickname);
     routerinfo_free(ri);
     *desc = end;
-    return 0;
+    return -1;
   }
   /* Do we already have an entry for this router? */
   desc_ent_ptr = NULL;
@@ -263,10 +261,10 @@ dirserv_add_descriptor(const char **desc)
     if ((*desc_ent_ptr)->published > ri->published_on) {
       /* We already have a newer descriptor */
       log_fn(LOG_INFO,"We already have a newer desc for nickname %s. Not adding.",ri->nickname);
-      /* This isn't really an error; return. */
+      /* This isn't really an error; return success. */
       routerinfo_free(ri);
       *desc = end;
-      return 0;
+      return 1;
     }
     /* We don't have a newer one; we'll update this one. */
     free_descriptor_entry(*desc_ent_ptr);
@@ -287,13 +285,7 @@ dirserv_add_descriptor(const char **desc)
   directory_set_dirty();
 
   routerinfo_free(ri);
-  return 0;
- err:
-  tor_free(desc_tmp);
-  if (ri)
-    routerinfo_free(ri);
-
-  return -1;
+  return 1;
 }
 
 void
@@ -310,7 +302,7 @@ dirserv_init_from_directory_string(const char *dir)
     cp = strstr(cp, "\nrouter ");
     if (!cp) break;
     ++cp;
-    if (dirserv_add_descriptor(&cp)) {
+    if (dirserv_add_descriptor(&cp) < 0) {
       return -1;
     }
     --cp; /*Back up to newline.*/
diff --git a/src/or/router.c b/src/or/router.c
index 387169d956..db2a7f3b1f 100644
--- a/src/or/router.c
+++ b/src/or/router.c
@@ -161,7 +161,7 @@ int init_keys(void) {
     return -1;
   }
   tmp = mydesc = router_get_my_descriptor();
-  if (dirserv_add_descriptor(&tmp)) {
+  if (dirserv_add_descriptor(&tmp) != 1) {
     log(LOG_ERR, "Unable to add own descriptor to directory.");
     return -1;
   }