Bug#334350: fix from Gentoo for "flexbackup default config insecure temporary file creation"

[Alec Berryman]

Package: flexbackup
Followup-For: Bug #334350

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Gentoo has two patches for this issue.  The first [1], attached to bug
#105000 [2], is supposedly from Debian, but was apparently never
uploaded.  The patch reportedly breaks remote backups [3], though, and
bug #116510 [4] has a patch [5] that fixes both the original
vulnerability and the subsequent issues with remote backup.  The second
patch applies cleanly to Debian's version, but I have not tested it.

The second patch is attached unmodified.

[1] http://bugs.gentoo.org/attachment.cgi?id=69694&action=view
[2] http://bugs.gentoo.org/show_bug.cgi?id=105000
[3] http://bugs.gentoo.org/show_bug.cgi?id=105000#c15
[4] http://bugs.gentoo.org/show_bug.cgi?id=116510
[5] http://bugs.gentoo.org/attachment.cgi?id=86773&action=view


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--- flexbackup  2003-10-10 07:12:09.000000000 -0700
+++ /usr/bin/flexbackup 2006-05-14 13:14:54.000000000 -0700
@@ -269,6 +269,7 @@
     untie(%::index);
 }
 
+system ('rm', '-rf', $cfg::tmpdir);
 exit(0);
 
 ######################################################################
@@ -811,6 +812,11 @@
        ($remove, @cmds) = &backup_filelist($label, $localdir, $title, $level, 
$remote);
     }
 
+       if(defined($remote)) {
+               # create our temporary directory as first remote command
+               unshift(@cmds, &maybe_remote_cmd("$::path{mkdir} -p 
$cfg::tmpdir", $remote));
+       }
+
     # Nuke any tmp files used in the above routines
     if ($remove ne '') {
        push(@cmds, &maybe_remote_cmd("$::path{rm} -f $remove", $remote));
@@ -827,6 +833,11 @@
            push(@cmds, &maybe_remote_cmd("$::path{rm} -f $pkglist", $remote));
        }
     }
+       
+       if(defined($remote)) {
+               # remove temporary directory as our last remote command
+               push(@cmds, &maybe_remote_cmd("$::path{rm} -rf $cfg::tmpdir", 
$remote));
+       }
 
     # Strip multiple spaces
     foreach my $cmd (@cmds) {
@@ -2750,8 +2761,9 @@
     $::path{'find'} = &checkinpath('find');
     $::path{'dd'} = &checkinpath('dd');
     $::path{'printf'} = &checkinpath('printf');
+    $::path{'mkdir'} = &checkinpath('mkdir');
 
-    
push(@::remoteprogs,($::path{'touch'},$::path{'rm'},$::path{'find'},$::path{'printf'}));
+    
push(@::remoteprogs,($::path{'touch'},$::path{'rm'},$::path{'find'},$::path{'printf'},$::path{'mkdir'}));
 
     # Check device (or dir)
     $::ftape = 0;
@@ -3442,6 +3454,15 @@
        push(@::errors,"\$tmpdir $cfg::tmpdir is not writable");
     }
 
+       $cfg::hostname = `hostname`;
+       chomp($cfg::hostname);
+
+       # Use a subdirectory of the user-specified directory as our tmpdir
+       # Also note that we make it closer to globally unique as we sometimes
+       # use this variable for remote systems, so PID isn't enough
+    $cfg::tmpdir = $cfg::tmpdir .'/flexbackup.'.$$.'.'.$cfg::hostname;
+    mkdir ($cfg::tmpdir) || die "Can't create temporary directory, $!";
+
     # Levels
     if (defined($::opt{'level'}) and
        (defined($::opt{'incremental'}) or
@@ -5236,8 +5257,8 @@
     # Create a script which tests the buffer program
     open(SCR,"> $tmp_script") || die;
     print SCR "#!/bin/sh\n";
-    print SCR "tmp_data=/tmp/bufftest\$\$.txt\n";
-    print SCR "tmp_err=/tmp/bufftest\$\$.err\n";
+    print SCR "tmp_data=\`tempfile\`\n";
+    print SCR "tmp_err=\`tempfile\`\n";
     print SCR "echo testme > \$tmp_data\n";
     print SCR "$buffer_cmd > /dev/null 2> \$tmp_err < \$tmp_data\n";
     print SCR "res=\$?\n";