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btrbk
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btrbk: do not run in perl taint mode by default: remove "perl -T" in hashbang; hardcode $PATH only if taint mode is enabled 

While taint mode [1] is a nice feature of perl, e.g. it disallows
using variables (such as filenames from the config file) which were
not validated in system() commands, it also treats $PATH as insecure
(which inherently is, as perl cannot know who messed around with it).

  [1] perlsec(1): http://perldoc.perl.org/perlsec.html
  [2] perlrun(1): http://perldoc.perl.org/perlrun.html

Note that btrbk still does all taint checks, and can be run in taint
mode:

  - by executing `perl -T /usr/sbin/btrbk`,
  - or by changing the hashbang to: `!#/usr/bin/perl -T`.
pull/204/head
Axel Burri 2017-09-25 16:05:42 +02:00
parent 5f867c2347
commit 571dae4428
2 changed files with 19 additions and 5 deletions
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2
ChangeLog
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@ -4,6 +4,8 @@ btrbk-current
line option (which is now deprecated).
* Add "snapshot" command (close #150).
* Add "--preserve-snapshots" and "--preserve-backups" options.
* Do not run in "perl taint mode" by default: remove "perl -T" in
hashbang; hardcode $PATH only if taint mode is enabled.
* Remove "duration" column from transaction_log/transaction_syslog.
* Bugfix: ssh_filter_btrbk: accept mbuffer command (stream_buffer).
* Bugfix: print correct (end-)time in transaction_log.

22
btrbk
View File

@ -1,4 +1,4 @@
#!/usr/bin/perl -T
#!/usr/bin/perl
#
# btrbk - Create snapshots and remote backups of btrfs subvolumes
#
@ -3707,10 +3707,22 @@ sub exit_status
MAIN:
{
# set PATH instead of using absolute "/sbin/btrfs" (for now), as
# different distros (and even different versions of btrfs-progs)
# install the "btrfs" executable to different locations.
$ENV{PATH} = '/sbin:/bin:/usr/sbin:/usr/bin';
# NOTE: Since v0.26.0, btrbk does not enable taint mode (perl -T) by
# default, and does not hardcode $PATH anymore.
#
# btrbk still does all taint checks, and can be run in taint mode.
# In order to enable taint mode, run `perl -T btrbk`.
#
# see: perlrun(1), perlsec(1)
#
my $taint_mode_enabled = eval '${^TAINT}';
if($taint_mode_enabled) {
# we are running in tainted mode (perl -T), sanitize %ENV
delete @ENV{qw(IFS CDPATH ENV BASH_ENV)};
# in taint mode, perl needs an untainted $PATH.
$ENV{PATH} = '/sbin:/bin:/usr/sbin:/usr/bin';
}
Getopt::Long::Configure qw(gnu_getopt);
my $start_time = time;