SUID check

n00dles has asked for the wisdom of the Perl Monks concerning the following question:

Hello all, Once again im alittle stuck and my ideas seem to surpass my ability. I'm trying to compare two files that store info on my SUID files for changes and print the details to a web page, im happy with it for the most part, I understand why the output is not produced but have no idea what so ever how to remede the situation.

#!/usr/bin/perl -w

use strict;

my $setuidtoday = "/var/log/setuid.today";
my $setuidyest = "/var/log/setuid.yesterday";
my $DIFF = "/usr/bin/diff";

print "Content-type: text/html\n\n";
print "<HTML><TITLE>SET SUID FILE CHECK</TITLE>\n";
print "<BODY BGCOLOR=#000000 Text=#008000 link=#00c000\n";
print "<H1>SET SUID FILE CHECK</H1>\n";

if(-e $setuidtoday && $setuidyest) {
        print "<H6>Setuid lists exist!</H6>\n";
        print `$DIFF $setuidtoday $setuidyest`;
}
print "</BODY></HTML>";
[download]

I believe its this line

print `$DIFF $setuidtoday $setuidyest`;
[download]

It works fine at the CLI but the output from diff is not displayed in the webpage, I can see why that is but dont know how to fix the issue... Also if anyone has any improvements please say. The reason I have not used any modules for HTML prasing etc... is because I haven't got that far in my study and i'd like to see what I can code with base perl before I branch out.

n00dles
lynx.neocyber.info

Comment on SUID check Select or Download Code

Replies are listed 'Best First'.
Re: SUID check by Tanktalus (Canon) on Aug 04, 2006 at 14:37 UTC
You say you know why, but don't elaborate. So, I suppose my first question is - why do you think it doesn't display in the webpage? Without that information, my first guess is that diff isn't outputting HTML, so some of it may get lost by the webclient - but the data is still there. So I'd suggest something like: print "<pre>", `$DIFF ...`, "</pre>"; [download] The diff output is pre-formatted anyway. If you want to spice this up, you'll have to parse the output and deal with that yourself - but that's stage 4 or 5 of this process, I bet ;-) Minor nit: I think you mean `if(-e $setuidtoday && -e $setuidyest)`. The -e operator doesn't go across the && the way you seem to think it does. Since $setuidyest is always true, the way you have it, that's a no-op. You probably want to test its existance.	[reply] [d/l] [select]
Re: SUID check by jhourcle (Prior) on Aug 04, 2006 at 16:23 UTC
It works fine at the CLI but the output from diff is not displayed in the webpage, I can see why that is but dont know how to fix the issue... Also if anyone has any improvements please say. The reason I have not used any modules for HTML prasing etc... is because I haven't got that far in my study and i'd like to see what I can code with base perl before I branch out. If you don't use the modules for anything else -- use them for escaping the output from your diff command. Diff lines start with '<' and '>', which are special in HTML (as is '&') You need to encode them as : < > and & Your other option is to serve the page as text/plain as opposed to text/html	[reply]
Re^2: SUID check by Argel (Prior) on Aug 04, 2006 at 22:33 UTC
Another option might be to do a diff -u and wrap that in pre tags (though there may still be characters that need to be escaped). It might be a quick fix.	[reply]
Re: SUID check by n00dles (Novice) on Aug 04, 2006 at 23:14 UTC
Code: #!/usr/bin/perl -w use strict; my $setuidtoday = "/var/log/setuid.today"; my $setuidyest = "/var/log/setuid.yesterday"; my $DIFF = "/usr/bin/diff -u"; my $out = `$DIFF $setuidtoday $setuidyest`; print "Content-type: text/html\n\n"; print "<HTML><TITLE>SET SUID FILE CHECK</TITLE>\n"; print "<BODY BGCOLOR=#000000 Text=#008000 link=#00c000 vlink=lightblue +>\n"; print "<H1>SET SUID FILE CHECK</H1>\n"; if(-e $setuidtoday && -e $setuidyest) { print "<H6>Setuid lists exist!</H6>\n"; print "<CODE><BR>\n"; print "$out\n"; } #print `$DIFF $setuidtoday $setuidyest`; print "</BODY></HTML>"; [download] CLI output: Content-type: text/html <HTML><TITLE>SET SUID FILE CHECK</TITLE> <BODY BGCOLOR=#000000 Text=#008000 link=#00c000 vlink=lightblue> <H1>SET SUID FILE CHECK</H1> <H6>Setuid lists exist!</H6> <CODE><BR> --- /var/log/setuid.today Wed Jul 12 03:03:52 2006 +++ /var/log/setuid.yesterday Fri Jun 30 03:03:13 2006 @@ -3,11 +3,11 @@ 31837 -r-sr-xr-x 1 root wheel 21792 Nov 3 08:10:37 2005 /sbin +/ping 31838 -r-sr-xr-x 1 root wheel 28660 Nov 3 08:10:37 2005 /sbin +/ping6 31850 -r-sr-x--- 1 root operator 10148 Nov 3 08:10:38 2005 /sbin +/shutdown -1040389 -rws--x--x 1 root wheel 3348 Oct 12 20:39:40 2005 /usr/ +X11R6/bin/Eterm +1040389 -rws--x--x 1 root wheel 3348 Oct 12 20:39:40 2005 /u +sr/X11R6/bin/Eterm 1040154 -rws--x--x 1 root wheel 1664917 Oct 12 17:23:09 2005 /u +sr/X11R6/bin/Xorg -1040397 -rws--x--x 1 root wheel 94008 Oct 12 15:44:09 2005 /usr/ +X11R6/bin/aterm </BODY></HTML> [download] WWW output: `<HTML><TITLE>SET SUID FILE CHECK</TITLE> <BODY BGCOLOR=#000000 Text=#008000 link=#00c000 vlink=lightblue> <H1>SET SUID FILE CHECK</H1> <H6>Setuid lists exist!</H6> <CODE><BR> </BODY></HTML>` [download] I really dont get this. file permissions are correct too. n00dles lynx.neocyber.info	[reply] [d/l] [select]
Re: SUID check by n00dles (Novice) on Aug 04, 2006 at 22:00 UTC
I tryed using PRE tags etc.. and the CODE tags are there to solve the < > issues. But still no output. Is there a way I can store the output in a variable? or redirect STDOUT? n00dles lynx.neocyber.info	[reply]
Re^2: SUID check by Argel (Prior) on Aug 04, 2006 at 22:39 UTC
my $out = `$DIFF $setuidtoday $setuidyest`; print $out; [download] You might want to try: use Data::Dumper; my $out = `$DIFF $setuidtoday $setuidyest`; print '<pre>', Data::Dumper->Dump([$out],['out']), '</pre>'; [download]	[reply] [d/l] [select]
Re: SUID check by Argel (Prior) on Aug 04, 2006 at 22:49 UTC
Could you be over thinking this? If the two files are identical then you would get no output, right? Could that be the case?	[reply]

Code:

CLI output:

WWW output: