[LON-CAPA-users] need help with odd error

Sally S Hunnicutt/FS/VCU lon-capa-users@mail.lon-capa.org
Mon, 29 Nov 2010 18:16:45 -0500

<font size=3D"2" face=3D"Default Sans Serif,Verdana,Arial,Helvetica,sans-se=
rif"><div>Thanks for the responses.<br><br>Yes, VCU uses https.<br><br>For =
the second question - the code actually shows up in the problem before anyt=
hing is submitted.&nbsp; She never actually sees the question.<br><br>Sally=
<br></div><div><br><div><br></div><font color=3D"#990099">-----lon-capa-use=
rs-admin@mail.lon-capa.org wrote: -----<br><br></font><blockquote style=3D"=
padding-right: 0px; padding-left: 5px; margin-left: 5px; border-left: 2px s=
olid #000000; margin-right: 0px;">To: <a class=3D"moz-txt-link-abbreviated"=
apa.org</a><br>From: Gerd Kortemeyer <a class=3D"moz-txt-link-rfc2396E" hre=
f=3D"mailto:korte@lite.msu.edu">&lt;korte@lite.msu.edu&gt;</a><br>Sent by: =
<a class=3D"moz-txt-link-abbreviated" href=3D"mailto:lon-capa-users-admin@m=
ail.lon-capa.org">lon-capa-users-admin@mail.lon-capa.org</a><br>Date: 11/29=
/2010 04:01PM<br>Subject: Re: [LON-CAPA-users] need help with odd error<br>=
<br><font size=3D"3" face=3D"Courier New,Courier,monospace">Hi,<br><br>Ther=
e are two reasons I can think of:<br><br>* Peter Riegler just described one=
 of the two possible reasons. Do you use https?<br><br>* My other guess is =
that something the student entered looks like a "quoted execution," i.e., s=
omething that is supposed to be executed on the command line. Most likely, =
she entered backticks, and more than likely, she did so inadvertently. The =
problem itself is not dangerous, after all, this got caught by the safe env=
ironment. The only problem is that it reveals part of the source code. It w=
ould be good to know exactly what the student entered on which problem. We =
could then filter out the characters before they are caught by the "last re=
sort" safeeval code.<br><br>- Gerd.<br><br><br>On Nov 29, 2010, at 3:38 PM,=
 Sally S Hunnicutt/FS/VCU wrote:<br><br>&gt; Hello, <br>&gt; <br>&gt; One o=
f our students is enrolled in three different LC courses on campus. &nbsp;I=
n one of those courses, she gets errors like the one at the end of this ema=
il. &nbsp;This happens for about 1/3 of her problems, but only toward the l=
atter half of the course. &nbsp;This does not happen for any other students=
 in this course, nor in any of her other courses. &nbsp;It happens when she=
 uses IE or Firefox as her browser on a PC (not a Mac). &nbsp;Eric Harvey s=
uggested it might be something &nbsp;to do with a Perl security feature - b=
ut that still doesn't seem to explain why the problem comes up so randomly.=
 &nbsp;I am the author of these problems. &nbsp; <br>&gt; <br>&gt; Any idea=
s? &nbsp;Thanks. <br>&gt; <br>&gt; &nbsp;'quoted execution (``, qx)' trappe=
d by operation maskCompilation failed in require at /usr/lib/perl5/5.8.8/Au=
toLoader.pm line 92.<br>&gt; at /usr/lib/perl5/vendor=5Fperl/5.8.8/IO/Socke=
t/SSL.pm line 401<br>&gt; occurred while running #Enter the computations he=
re<br>&gt; $reaction=3D&amp;amp;chemparse(&amp;quot;H2(g)+I2(g)-&gt;2HI(g)&=
amp;quot;);<br>&gt; <br>&gt; $K=3D&amp;amp;format(129,'3s');<br>&gt; <br>&g=
t; $PHI=3D&amp;amp;format(&amp;amp;random(0.01,10.0,0.005),'3s');<br>&gt; $=
PH2=3D&amp;amp;format(&amp;amp;random(0.01,1.0,0.005),'3s');<br>&gt; $PI2=
=3D$PH2;<br>&gt; $Q=3D&amp;amp;format(&amp;amp;pow($PHI,2)/($PH2*$PI2),'3s'=
);<br>&gt; $sqrtK=3D&amp;amp;format(&amp;amp;sqrt($K),'3s');<br>&gt; if ( $=
Q&gt;$K ) {<br>&gt; &nbsp; $x=3D&amp;amp;format(((-$sqrtK*$PH2+$PHI)/($sqrt=
K+2)),'3s');<br>&gt; &nbsp; @shifttrue=3D(&amp;quot;The reaction shifts lef=
t.&amp;quot;,&amp;quot;More reactants will form from products.&amp;quot;);<=
br>&gt; &nbsp; @shiftfalse1=3D(&amp;quot;The reaction shifts right.&amp;quo=
t;,&amp;quot;More products will form from reactants.&amp;quot;);<br>&gt; &n=
bsp; @shiftfalse2=3D(&amp;quot;The reaction is at equilibrium.&amp;quot;,&a=
mp;quot;The concentrations of products and reactants will not change.&amp;q=
uot;);<br>&gt; &nbsp; $PHIe=3D&amp;amp;format($PHI-2*$x,'3s');<br>&gt; &nbs=
p; $PH2e=3D&amp;amp;format($PH2+$x,'3s');<br>&gt; &nbsp; $PI2e=3D$PH2e;<br>=
&gt; &nbsp; }<br>&gt; elsif ( $QThis error occurred while processing part 0=
The error occurred on host vcua1 <br>&gt; &lt;Mail Attachment.jpeg&gt;<br><=
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