Reject most directory documents with an internal NUL.

(Specifically, we reject all the ones that aren't NUL-terminated,
since a NUL-terminated thing can't have a NUL in the middle.)

Another fix for #8037.

1 files changed, 8 insertions, 1 deletions

diff --git a/src/or/routerparse.c b/src/or/routerparse.c
index 23dae382fc..2c345ae113 100644
--- a/src/or/routerparse.c
+++ b/src/or/routerparse.c
@@ -3902,8 +3902,15 @@ tokenize_string(memarea_t *area,
   tor_assert(area);
 
   s = &start;
-  if (!end)
+  if (!end) {
     end = start+strlen(start);
+  } else {
+    /* it's only meaningful to check for nuls if we got an end-of-string ptr */
+    if (memchr(start, '\0', end-start)) {
+      log_warn(LD_DIR, "parse error: internal NUL character.");
+      return -1;
+    }
+  }
   for (i = 0; i < NIL_; ++i)
     counts[i] = 0;