Wireshark-dev: Re: [Wireshark-dev] invalid output in pidl generated dcercp-mapi & dercp-nspi di
From: Alexis La Goutte <[email protected]>
Date: Fri, 12 Feb 2016 10:45:51 +0100
Hi Aurélien,

Yes, There is some issue with mapi dissector actually
we have no the same result when regenerate mapi dissector...
https://code.wireshark.org/review/#/c/11476/

And yes, the code don't build...

Cheers

On Thu, Feb 11, 2016 at 4:26 PM, Aurélien Aptel <[email protected]> wrote:
Hi,

I'm in the process of syncing tools/pidl with samba (almost done, more
on this later).

Using master (0cd0844) bundled pidl, I wanted to make sure none of the
generated dissectors were edited by hand so I've run the following
(from epan/dissectors/pidl/README) to regenerate them:

    cd epan/dissectors/pidl
    for file in *.idl */*.idl; do
        echo "Generating dissector for $file"
        ../../../tools/pidl/pidl --includedir . --ws-parser -- $file;
    done
    cp packet-dcerpc*.* ..

Most generated files are almost identical (slightly altered comments and
whitespace because pidl wasn't run again) except for
packet-dcerpc-mapi.[ch] and packet-dcerpc-nsapi.[ch] who differs
greatly. These new generated files don't compile because they are
malformed. Sample output:

static int
mapi_dissect_element_SPropValue_value(tvbuff_t *tvb _U_, int offset _U_, packet_info *pinfo _U_, proto_tree *tree _U_, dcerpc_info* di _U_, guint8 *drep _U_, guint32 *)
{
        offset = mapi_dissect_SPropValue_CTR(tvb, offset, pinfo, tree, di, drep, hf_mapi_property_types, *);

        return offset;
}


Notice the lone * at the last param of the call.
I've tried to debug it (but I don't know much about pidl)

in tools/pidl/lib/Parse/Pidl/Wireshark/NDR.pm:446 (sub Element)

        if (defined $isoruseswitch) {
                my $type = $isoruseswitch->[0];
                my $name = $isoruseswitch->[1];

                my $switch_dt =  getType($type);
                my $switch_raw_type = SwitchType($e, $type, "uint32");
                if (not defined($switch_raw_type)) {
                        die("Unknown type[$type]\n");
                }
                my $switch_type = "g${switch_raw_type}";

                $moreparam = ", $switch_type *".$name;

                if (($e->{PROPERTIES}->{switch_is} eq "") && ($switchvars{$name}) &&
                        #not a "native" type
                        (!($type =~ /^uint(8|16|1632|32|3264|64)/))) {
                        $param = $name;
                } elsif ( $switch_dt->{DATA}->{TYPE} eq "ENUM") {
                        $param = $name;
                } else {
                        $param = "*".$name;
                        # ^^^^^^^^^^^^^^^^^
                        # here we prefix the param
                        # with a star but $name is empty
                }

Later in the same sub we call ElementLevel with $param eq "*"

                $self->ElementLevel($e,$_,$hf,$dissectorname.$add,$pn,$ifname,$param);

Finally, in the sub ElementLevel we generate the wrong call:

        } elsif (defined($self->{conformance}->{types}->{$l->{DATA_TYPE}})) {
                $call= $self->{conformance}->{types}->{$l->{DATA_TYPE}}->{DISSECTOR_NAME};
                $self->{conformance}->{types}->{$l->{DATA_TYPE}}->{USED} = 1;
        } else {


Here $call is set to

"offset = mapi_dissect_SPropValue_CTR(tvb, offset, pinfo, tree, di, drep, @[email protected], @[email protected]);"

And @[email protected] is replaced with "*".

--
Aurélien Aptel / SUSE Labs Samba Team
GPG: 1839 CB5F 9F5B FB9B AA97  8C99 03C8 A49B 521B D5D3
SUSE Linux GmbH, Maxfeldstraße 5, 90409 Nürnberg, Germany
GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG
Nürnberg)

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