Wireshark-bugs: [Wireshark-bugs] [Bug 4755] New: Negative file size

Date: Tue, 11 May 2010 10:04:41 -0700 (PDT)
https://bugs.wireshark.org/bugzilla/show_bug.cgi?id=4755

           Summary: Negative file size
           Product: Wireshark
           Version: 1.2.5
          Platform: x86
        OS/Version: Windows 7
            Status: NEW
          Severity: Minor
          Priority: Low
         Component: Extras
        AssignedTo: wireshark-bugs@xxxxxxxxxxxxx
        ReportedBy: g.borello@xxxxxxxxx


Build Information:
wireshark 1.2.5 (SVN Rev 31296)

Copyright 1998-2009 Gerald Combs <gerald@xxxxxxxxxxxxx> and contributors.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

Compiled with GTK+ 2.16.2, with GLib 2.20.3, with WinPcap (version unknown),
with libz 1.2.3, without POSIX capabilities, with libpcre 7.0, with SMI 0.4.8,
with c-ares 1.6.0, with Lua 5.1, with GnuTLS 2.8.1, with Gcrypt 1.4.4, with MIT
Kerberos, with GeoIP, with PortAudio V19-devel (built Dec 17 2009), with
AirPcap.

Running on 32-bit Windows 7, build 7600, without WinPcap, GnuTLS 2.8.1, Gcrypt
1.4.4, without AirPcap.

Built using Microsoft Visual C++ 9.0 build 30729
--
D:\captures>"c:\Program Files\Wireshark\capinfos.exe" net15full.acp
File name:           net15full.acp
File type:           Wireshark/tcpdump/... - libpcap
File encapsulation:  Ethernet
Number of packets:   5854353
File size:           -294965958 bytes
Data size:           3906331666 bytes
Capture duration:    3388 seconds
Start time:          Fri May 11 14:04:36 2007
End time:            Fri May 11 15:01:05 2007
Data byte rate:      1152841.40 bytes/sec
Data bit rate:       9222731.20 bits/sec
Average packet size: 667.25 bytes
Average packet rate: 1727.74 packets/sec

As you can see, the file size reported by the tool is a negative number, while
my file is 4.000.001.338 bytes.
I'm using Windows 7 (32 bit). The file is stored on a NTFS partition.
Now, reading some lines of code in capinfos.c, I noticed that the file size is
handled using a gint64 type, so there shouldn't be any problem.
Unfortunately, I don't have enough time to investigate, but it seems like file
size is somewhere managed as a 32 bit variable:

4.000.001.338 = 0xEE6B2D3A

Now, let's do an explicit cast from a 32 bit variable to a 64 bit variable,
doing sign extension:

(gint64) 0xEE6B2D3A = 0xFFFFFFFFEE6B2D3A = -294.965.958

And this is the same value capinfos is giving to me.

Unfortunately (again), I don't have enough time to test this minor issue on
another platforms.

Thank you for your work.

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