Wireshark mailing list archives

Re: Coverity warning in tshark.c


From: Jakub Zawadzki <darkjames-ws () darkjames pl>
Date: Tue, 22 Oct 2013 18:59:16 +0200

Hi Joerg,

On Mon, Oct 21, 2013 at 11:58:17PM +0200, Joerg Mayer wrote:
Looks like coverity has a valid complaint:

CID 1109702: Dereference after null check (FORWARD_NULL)

/tshark.c: 2859 ( var_compare_op)
   2856      /* If we're going to print packet information, or we're going to
   2857         run a read filter, or we're going to process taps, set up to
   2858         do a dissection and do so. */
Comparing "edt" to null implies that "edt" might be null.
   2859      if (edt) {
   2860        if (gbl_resolv_flags.mac_name || gbl_resolv_flags.network_name ||
   2861            gbl_resolv_flags.transport_name || gbl_resolv_flags.concurrent_dns)
   2862          /* Grab any resolved addresses */
   2863          host_name_lookup_process();


/tshark.c: 2903 ( var_deref_model)
   2900        if (print_packet_info) {
   2901          /* We're printing packet information; print the information for
   2902             this packet. */
Passing null variable "edt" to function "print_packet", which dereferences it.
   2903          print_packet(cf, edt);
   2904
   2905          /* The ANSI C standard does not appear to *require* that a line-buffered
   2906             stream be flushed to the host environment whenever a newline is
   2907             written, it just says that, on such a stream, characters "are

I don't see a problem.
Previously print_packet() was also passing edt as NULL

-      if (do_dissection)
-        print_packet(cf, &edt);
-      else
-        print_packet(cf, NULL);

I simplified it, just to:

+      print_packet(cf, edt);

No idea how to fix it, sorry. Most likely it's false positive.
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