[LogReport Development] Bug: Integer Overflow causes endless loop

[Joost van Baal]

Hi,

Op Tue 24 Jul 2007 om 06:57:07 +0200 schreef Skora, Thomas:
> 
> I'm have a problem with Lire 2.0.1 (also with 2.0.2 - mainly the prior
> release is used since the distribution supports it) when big transfers
> are logged in a squid log file and the subreport "Requests by Size" is
> generated. The command I use is:
> lr_log2report --output-format xml squid_access squid.log report.xml
> 
> When a line with a file transfer bigger than 2^31 bytes is processed by
> lire it hangs in the while loop from line 397 (sub create_entry) in
> Rangegroup.pm because the variable $value is filled with an negative
> value. The error seems to appear somewhere while the function
> Lire::SQLExt::LrRangegroup::lr_rangegroup_geo returns its big (>2^32) to
> SQLite because the rangegroup column returned by SQLite after the query
> contains a negative value.
> 
> I thought that was an DBD::SQLite2 issue, but on the test box (64 bit)
> example programs simulating such a constellation work fine.
> 
> The attached patch moves the problem to some gigabytes above the actual
> limit by adding a constant to negative values. It not really fixes the
> problem but omits the endless loop for several million log lines. The
> patch contains also a second fix for Lire::SQLExt::LrRangegroup where
> bad formatted decimal numbers (, instead of . as decimal comma) from
> SQLite cause many perl warnings.

Thanks a lot for this patch, it is very much appreciated!

I'll take a closer look at it soonish, will try to test it and will try
to get it shipped with next Lire release.

However, isn't the overflow problem caused by a bug in SQLite (or
DBD::SQLite2)?  I don't think the Lire code is what should be fixed
here.  Did you try to locate the bug?  Did you report it to the SQLite
(or DBD::SQLite2) maintainers?

(the patch, inline this time:

diff -ur /root/Lire/Rangegroup.pm Lire/Rangegroup.pm
--- /root/Lire/Rangegroup.pm    2006-08-29 10:25:06.000000000 +0200
+++ Lire/Rangegroup.pm  2007-07-24 17:54:16.000000000 +0200
@@ -396,7 +396,7 @@
     my $start = $self->_param_value( 'range_start');
     my $scale = $self->_param_value( 'size_scale' );
 
-
+    $value = -$value + 2**32 if ($value < 0); # workaround for overflow problem
     while ( $value < $start || $value >= ( $start + $length ) ) {
         $start += $length;
         $length *= $scale;
diff -ur /root/Lire/SQLExt/LrRangegroup.pm Lire/SQLExt/LrRangegroup.pm
--- /root/Lire/SQLExt/LrRangegroup.pm   2005-04-26 05:15:49.000000000
+0200
+++ Lire/SQLExt/LrRangegroup.pm 2007-07-24 18:01:30.000000000 +0200
@@ -24,6 +24,7 @@
     $v = $min if defined $min && $v < $min;
     $v = $max if defined $max && $v > $max;
 
+    $v =~ s/,/./;              # fix: numbers are sometimes in bad format 
     return undef if $v < $start;
 
     my $range_start = $start;



)

Thanks!

Bye,

Joost


-- 
.    .                           Log Analysis and Report Generation
| '.|        /^LogReport$/
| Lire                                    http://www.logreport.org/
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 827 bytes
Desc: Digital signature
Url : http://lists.logreport.org/pipermail/development/attachments/20070729/33c0e4a5/attachment.bin