[tor-commits] [tor/master] sendme: Fix coverity CID 1444999

[nickm at torproject.org]

commit def96ce83858b214ebc01797e41e4f0419f9d104
Author: David Goulet <dgoulet at torproject.org>
Date:   Mon May 13 10:00:39 2019 -0400

    sendme: Fix coverity CID 1444999
    
    The code flow in theory can end up with a layer_hint to be NULL but in
    practice it should never happen because with an origin circuit, we must have
    the layer_hint.
    
    Just in case, BUG() on it if we ever end up in this situation and recover by
    closing the circuit.
    
    Fixes #30467.
    
    Signed-off-by: David Goulet <dgoulet at torproject.org>
---
 src/core/or/sendme.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/src/core/or/sendme.c b/src/core/or/sendme.c
index 46fdc3ca1..e7c65d99e 100644
--- a/src/core/or/sendme.c
+++ b/src/core/or/sendme.c
@@ -412,6 +412,11 @@ sendme_process_circuit_level(crypt_path_t *layer_hint,
   /* If we are the origin of the circuit, we are the Client so we use the
    * layer hint (the Exit hop) for the package window tracking. */
   if (CIRCUIT_IS_ORIGIN(circ)) {
+    /* If we are the origin of the circuit, it is impossible to not have a
+     * cpath. Just in case, bug on it and close the circuit. */
+    if (BUG(layer_hint == NULL)) {
+      return -END_CIRC_REASON_TORPROTOCOL;
+    }
     if ((layer_hint->package_window + CIRCWINDOW_INCREMENT) >
         CIRCWINDOW_START_MAX) {
       static struct ratelim_t exit_warn_ratelim = RATELIM_INIT(600);