Update fuzz target

Author: catenacyber

fuzz/CMakeLists.txt

@@ -1,2 +1,12 @@
-add_executable(fuzz_pcap onefile.c fuzz_pcap.c)
-target_link_libraries(fuzz_pcap netdissect ${TCPDUMP_LINK_LIBRARIES})
+set(fuzz_pcap_src fuzz_pcap.c)
+set(fuzz_pcap_libs netdissect ${TCPDUMP_LINK_LIBRARIES})
+
+IF(DEFINED ENV{LIB_FUZZING_ENGINE})
+	set(fuzz_pcap_libs ${fuzz_pcap_libs} $ENV{LIB_FUZZING_ENGINE})
+else()
+	set(fuzz_pcap_src ${fuzz_pcap_src} onefile.c)
+endif()
+
+add_executable(fuzz_pcap ${fuzz_pcap_src})
+set_target_properties(fuzz_pcap PROPERTIES LINKER_LANGUAGE CXX)
+target_link_libraries(fuzz_pcap ${fuzz_pcap_libs})

fuzz/fuzz_pcap.c

@@ -94,7 +94,9 @@ int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
         fprintf(outfile, "Couldn't open pcap file %s\n", errbuf);
         return 0;
     }
-    if (lookup_printer(pcap_datalink(pkts)) == NULL) {
+    if_printer_t printer;
+    printer = lookup_printer(&Ndo, pcap_datalink(pkts));
+    if (printer.printer == NULL) {
         //do not go further if we have no printer
         pcap_close(pkts);
         return 0;