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This queue is for tickets about the Proc-ProcessTable CPAN distribution.

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The Basics
Id: 72862
Status: resolved
Priority: 0/
Queue: Proc-ProcessTable

Owner: Nobody in particular
Cc: ether [...]

Bug Information
Severity: Important
Broken in: (no value)
Fixed in: (no value)


From: CARNIL [...]
Subject: unsafe use of /tmp
Hi This bug has been forwarded from Package: libproc-processtable-perl Version: 0.45-1 Severity: important Tags: security Proc::ProcessTable can cache TTY information (not enabled by default). For this it uses the file /tmp/TTYDEVS. If caching is enabled, there is a race condition that allows to overwrite arbitrary files in 102 if( -r $TTYDEVSFILE ) 103 { 104 $_ = Storable::retrieve($TTYDEVSFILE); [...] 107 else 108 { [...] 112 Storable::store(\%Proc::ProcessTable::TTYDEVS, $TTYDEVSFILE); If a symlink /tmp/TTYDEVS is created between line 102 and 112, the file the link points to is overwritten. Alternatively wrong information can be provided. The relevant code path can be reached with perl -MProc::ProcessTable -e 'my $t = Proc::ProcessTable->new(cache_ttys => 1, enable_ttys => 1); $t->table;' Ansgar References: [1] [2] Thanks in advance, Salvatore Bonaccorso, Debian Perl Group
Ping? Any chance this security issue is addressed?
This will be fixed, but with a completely different solution. Thanks for reporting, Jens
Would this be an appropriate patch?
Subject: tmp_ttydevs_file_security_fix.patch
diff --git a/ b/ index 03b741d..d3574ba 100644 --- a/ +++ b/ @@ -4,6 +4,7 @@ use 5.006; use strict; use Carp; +use Fcntl; use vars qw($VERSION @ISA @EXPORT @EXPORT_OK $AUTOLOAD); require Exporter; @@ -109,7 +110,12 @@ sub initialize $self->_get_tty_list; my $old_umask = umask; umask 022; - Storable::store(\%Proc::ProcessTable::TTYDEVS, $TTYDEVSFILE); + + sysopen( my $ttydevs_fh, $TTYDEVSFILE, O_WRONLY | O_EXCL | O_CREAT ) + or die "$TTYDEVSFILE was created by other process"; + Storable::store_fd( \%Proc::ProcessTable::TTYDEVS, $ttydevs_fh ); + close $ttydevs_fh; + umask $old_umask; } }
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On 2012-11-09 13:13:14, jwb wrote: Show quoted text
> Would this be an appropriate patch?
Another problem is that different perl versions with different byte orders (i.e. a 32bit perl vs. a 64bit perl) would still use the same file name, but loading the Storable data would fail then. See So /tmp/TTYDEVS should possibly have the byteorder in the filename, too (i.e. /tmp/TTYDEVS_1234 or /tmp/TTYDEVS_12345678 or /tmp/TTYDEVS_87654321 ...) Regards, Slaven
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fixed v0.47, the TTYDEVSFILE issue is fixed in github ( https:// ) and will be part of next release.

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