From edd289c64521396b52efbdc31b92d2216ab5aa24 Mon Sep 17 00:00:00 2001
From: Matias Fontanini <matias.fontanini@gmail.com>
Date: Tue, 30 May 2017 19:45:20 -0700
Subject: [PATCH] Don't dereference vector if empty on RadioTapWriter

---
 src/utils/radiotap_writer.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/utils/radiotap_writer.cpp b/src/utils/radiotap_writer.cpp
index 6bd030e..0608db8 100644
--- a/src/utils/radiotap_writer.cpp
+++ b/src/utils/radiotap_writer.cpp
@@ -74,7 +74,7 @@ void RadioTapWriter::write_option(const RadioTap::option& option) {
         }
         parser.advance_field();
     }
-    size_t offset = candidate_ptr - &*buffer_.begin();
+    size_t offset = is_empty ? 0 : candidate_ptr - &*buffer_.begin();
     const RadioTapParser::FieldMetadata& meta = RadioTapParser::RADIOTAP_METADATA[bit];
 
     vector<uint8_t> paddings = build_padding_vector(candidate_ptr, parser);