Commit | Line | Data |
---|---|---|
2ded1cc1 | 1 | package Safe; |
2 | ||
5f05dabc | 3 | use 5.003_11; |
2ded1cc1 | 4 | use strict; |
2ded1cc1 | 5 | |
6eed0921 | 6 | $Safe::VERSION = "2.19"; |
35ed0d3c DM |
7 | |
8 | # *** Don't declare any lexicals above this point *** | |
9 | # | |
10 | # This function should return a closure which contains an eval that can't | |
11 | # see any lexicals in scope (apart from __ExPr__ which is unavoidable) | |
12 | ||
13 | sub lexless_anon_sub { | |
14 | # $_[0] is package; | |
15 | # $_[1] is strict flag; | |
16 | my $__ExPr__ = $_[2]; # must be a lexical to create the closure that | |
17 | # can be used to pass the value into the safe | |
18 | # world | |
19 | ||
20 | # Create anon sub ref in root of compartment. | |
21 | # Uses a closure (on $__ExPr__) to pass in the code to be executed. | |
22 | # (eval on one line to keep line numbers as expected by caller) | |
23 | eval sprintf | |
24 | 'package %s; %s strict; sub { @_=(); eval q[my $__ExPr__;] . $__ExPr__; }', | |
25 | $_[0], $_[1] ? 'use' : 'no'; | |
26 | } | |
2ded1cc1 | 27 | |
5f05dabc | 28 | use Carp; |
bda6a610 RGS |
29 | BEGIN { eval q{ |
30 | use Carp::Heavy; | |
31 | } } | |
5f05dabc | 32 | |
2ded1cc1 | 33 | use Opcode 1.01, qw( |
34 | opset opset_to_ops opmask_add | |
35 | empty_opset full_opset invert_opset verify_opset | |
36 | opdesc opcodes opmask define_optag opset_to_hex | |
37 | ); | |
38 | ||
39 | *ops_to_opset = \&opset; # Temporary alias for old Penguins | |
40 | ||
41 | ||
42 | my $default_root = 0; | |
096e1543 RGS |
43 | # share *_ and functions defined in universal.c |
44 | # Don't share stuff like *UNIVERSAL:: otherwise code from the | |
45 | # compartment can 0wn functions in UNIVERSAL | |
46 | my $default_share = [qw[ | |
47 | *_ | |
48 | &PerlIO::get_layers | |
bb9fb662 NC |
49 | &UNIVERSAL::isa |
50 | &UNIVERSAL::can | |
51 | &UNIVERSAL::VERSION | |
52 | &utf8::is_utf8 | |
53 | &utf8::valid | |
54 | &utf8::encode | |
55 | &utf8::decode | |
56 | &utf8::upgrade | |
57 | &utf8::downgrade | |
58 | &utf8::native_to_unicode | |
59 | &utf8::unicode_to_native | |
1c92ff99 RGS |
60 | $version::VERSION |
61 | $version::CLASS | |
cd6d5856 | 62 | @version::ISA |
81d4a902 RGS |
63 | ], ($] >= 5.008001 && qw[ |
64 | &Regexp::DESTROY | |
65 | ]), ($] >= 5.010 && qw[ | |
096e1543 RGS |
66 | &re::is_regexp |
67 | &re::regname | |
68 | &re::regnames | |
69 | &re::regnames_count | |
70 | &Tie::Hash::NamedCapture::FETCH | |
71 | &Tie::Hash::NamedCapture::STORE | |
72 | &Tie::Hash::NamedCapture::DELETE | |
73 | &Tie::Hash::NamedCapture::CLEAR | |
74 | &Tie::Hash::NamedCapture::EXISTS | |
75 | &Tie::Hash::NamedCapture::FIRSTKEY | |
76 | &Tie::Hash::NamedCapture::NEXTKEY | |
77 | &Tie::Hash::NamedCapture::SCALAR | |
78 | &Tie::Hash::NamedCapture::flags | |
096e1543 | 79 | &UNIVERSAL::DOES |
096e1543 RGS |
80 | &version::() |
81 | &version::new | |
82 | &version::("" | |
83 | &version::stringify | |
84 | &version::(0+ | |
85 | &version::numify | |
86 | &version::normal | |
87 | &version::(cmp | |
88 | &version::(<=> | |
89 | &version::vcmp | |
90 | &version::(bool | |
91 | &version::boolean | |
92 | &version::(nomethod | |
93 | &version::noop | |
94 | &version::is_alpha | |
95 | &version::qv | |
bb9fb662 NC |
96 | ]), ($] >= 5.011 && qw[ |
97 | &re::regexp_pattern | |
98 | ])]; | |
2ded1cc1 | 99 | |
100 | sub new { | |
101 | my($class, $root, $mask) = @_; | |
102 | my $obj = {}; | |
103 | bless $obj, $class; | |
104 | ||
105 | if (defined($root)) { | |
106 | croak "Can't use \"$root\" as root name" | |
107 | if $root =~ /^main\b/ or $root !~ /^\w[:\w]*$/; | |
108 | $obj->{Root} = $root; | |
109 | $obj->{Erase} = 0; | |
110 | } | |
111 | else { | |
112 | $obj->{Root} = "Safe::Root".$default_root++; | |
113 | $obj->{Erase} = 1; | |
114 | } | |
115 | ||
116 | # use permit/deny methods instead till interface issues resolved | |
117 | # XXX perhaps new Safe 'Root', mask => $mask, foo => bar, ...; | |
118 | croak "Mask parameter to new no longer supported" if defined $mask; | |
119 | $obj->permit_only(':default'); | |
120 | ||
121 | # We must share $_ and @_ with the compartment or else ops such | |
122 | # as split, length and so on won't default to $_ properly, nor | |
123 | # will passing argument to subroutines work (via @_). In fact, | |
124 | # for reasons I don't completely understand, we need to share | |
125 | # the whole glob *_ rather than $_ and @_ separately, otherwise | |
126 | # @_ in non default packages within the compartment don't work. | |
127 | $obj->share_from('main', $default_share); | |
ac5e3691 | 128 | Opcode::_safe_pkg_prep($obj->{Root}) if($Opcode::VERSION > 1.04); |
2ded1cc1 | 129 | return $obj; |
130 | } | |
131 | ||
132 | sub DESTROY { | |
133 | my $obj = shift; | |
4d8e9581 | 134 | $obj->erase('DESTROY') if $obj->{Erase}; |
2ded1cc1 | 135 | } |
136 | ||
137 | sub erase { | |
4d8e9581 | 138 | my ($obj, $action) = @_; |
2ded1cc1 | 139 | my $pkg = $obj->root(); |
140 | my ($stem, $leaf); | |
141 | ||
142 | no strict 'refs'; | |
143 | $pkg = "main::$pkg\::"; # expand to full symbol table name | |
144 | ($stem, $leaf) = $pkg =~ m/(.*::)(\w+::)$/; | |
145 | ||
146 | # The 'my $foo' is needed! Without it you get an | |
147 | # 'Attempt to free unreferenced scalar' warning! | |
148 | my $stem_symtab = *{$stem}{HASH}; | |
149 | ||
150 | #warn "erase($pkg) stem=$stem, leaf=$leaf"; | |
151 | #warn " stem_symtab hash ".scalar(%$stem_symtab)."\n"; | |
152 | # ", join(', ', %$stem_symtab),"\n"; | |
153 | ||
4d8e9581 | 154 | # delete $stem_symtab->{$leaf}; |
2ded1cc1 | 155 | |
4d8e9581 GS |
156 | my $leaf_glob = $stem_symtab->{$leaf}; |
157 | my $leaf_symtab = *{$leaf_glob}{HASH}; | |
2ded1cc1 | 158 | # warn " leaf_symtab ", join(', ', %$leaf_symtab),"\n"; |
4d8e9581 | 159 | %$leaf_symtab = (); |
2ded1cc1 | 160 | #delete $leaf_symtab->{'__ANON__'}; |
161 | #delete $leaf_symtab->{'foo'}; | |
162 | #delete $leaf_symtab->{'main::'}; | |
163 | # my $foo = undef ${"$stem\::"}{"$leaf\::"}; | |
164 | ||
4d8e9581 GS |
165 | if ($action and $action eq 'DESTROY') { |
166 | delete $stem_symtab->{$leaf}; | |
167 | } else { | |
168 | $obj->share_from('main', $default_share); | |
169 | } | |
2ded1cc1 | 170 | 1; |
171 | } | |
172 | ||
173 | ||
174 | sub reinit { | |
175 | my $obj= shift; | |
176 | $obj->erase; | |
177 | $obj->share_redo; | |
178 | } | |
179 | ||
180 | sub root { | |
181 | my $obj = shift; | |
182 | croak("Safe root method now read-only") if @_; | |
183 | return $obj->{Root}; | |
184 | } | |
185 | ||
186 | ||
187 | sub mask { | |
188 | my $obj = shift; | |
189 | return $obj->{Mask} unless @_; | |
190 | $obj->deny_only(@_); | |
191 | } | |
192 | ||
193 | # v1 compatibility methods | |
194 | sub trap { shift->deny(@_) } | |
195 | sub untrap { shift->permit(@_) } | |
196 | ||
197 | sub deny { | |
198 | my $obj = shift; | |
199 | $obj->{Mask} |= opset(@_); | |
200 | } | |
201 | sub deny_only { | |
202 | my $obj = shift; | |
203 | $obj->{Mask} = opset(@_); | |
204 | } | |
205 | ||
206 | sub permit { | |
207 | my $obj = shift; | |
208 | # XXX needs testing | |
209 | $obj->{Mask} &= invert_opset opset(@_); | |
210 | } | |
211 | sub permit_only { | |
212 | my $obj = shift; | |
213 | $obj->{Mask} = invert_opset opset(@_); | |
214 | } | |
215 | ||
216 | ||
217 | sub dump_mask { | |
218 | my $obj = shift; | |
219 | print opset_to_hex($obj->{Mask}),"\n"; | |
220 | } | |
221 | ||
222 | ||
223 | ||
224 | sub share { | |
225 | my($obj, @vars) = @_; | |
226 | $obj->share_from(scalar(caller), \@vars); | |
227 | } | |
228 | ||
229 | sub share_from { | |
230 | my $obj = shift; | |
231 | my $pkg = shift; | |
232 | my $vars = shift; | |
233 | my $no_record = shift || 0; | |
50fc18f7 | 234 | my $root = $obj->root(); |
2ded1cc1 | 235 | croak("vars not an array ref") unless ref $vars eq 'ARRAY'; |
d00660f4 | 236 | no strict 'refs'; |
2ded1cc1 | 237 | # Check that 'from' package actually exists |
238 | croak("Package \"$pkg\" does not exist") | |
239 | unless keys %{"$pkg\::"}; | |
3fe9a6f1 | 240 | my $arg; |
2ded1cc1 | 241 | foreach $arg (@$vars) { |
242 | # catch some $safe->share($var) errors: | |
3fe9a6f1 | 243 | my ($var, $type); |
244 | $type = $1 if ($var = $arg) =~ s/^(\W)//; | |
245 | # warn "share_from $pkg $type $var"; | |
a930c511 DM |
246 | for (1..2) { # assign twice to avoid any 'used once' warnings |
247 | *{$root."::$var"} = (!$type) ? \&{$pkg."::$var"} | |
3fe9a6f1 | 248 | : ($type eq '&') ? \&{$pkg."::$var"} |
249 | : ($type eq '$') ? \${$pkg."::$var"} | |
250 | : ($type eq '@') ? \@{$pkg."::$var"} | |
251 | : ($type eq '%') ? \%{$pkg."::$var"} | |
252 | : ($type eq '*') ? *{$pkg."::$var"} | |
253 | : croak(qq(Can't share "$type$var" of unknown type)); | |
a930c511 | 254 | } |
2ded1cc1 | 255 | } |
256 | $obj->share_record($pkg, $vars) unless $no_record or !$vars; | |
257 | } | |
258 | ||
259 | sub share_record { | |
260 | my $obj = shift; | |
261 | my $pkg = shift; | |
262 | my $vars = shift; | |
263 | my $shares = \%{$obj->{Shares} ||= {}}; | |
264 | # Record shares using keys of $obj->{Shares}. See reinit. | |
265 | @{$shares}{@$vars} = ($pkg) x @$vars if @$vars; | |
266 | } | |
267 | sub share_redo { | |
268 | my $obj = shift; | |
269 | my $shares = \%{$obj->{Shares} ||= {}}; | |
d00660f4 | 270 | my($var, $pkg); |
2ded1cc1 | 271 | while(($var, $pkg) = each %$shares) { |
272 | # warn "share_redo $pkg\:: $var"; | |
273 | $obj->share_from($pkg, [ $var ], 1); | |
274 | } | |
275 | } | |
276 | sub share_forget { | |
277 | delete shift->{Shares}; | |
278 | } | |
279 | ||
280 | sub varglob { | |
281 | my ($obj, $var) = @_; | |
282 | no strict 'refs'; | |
283 | return *{$obj->root()."::$var"}; | |
284 | } | |
285 | ||
286 | ||
287 | sub reval { | |
288 | my ($obj, $expr, $strict) = @_; | |
50fc18f7 | 289 | my $root = $obj->{Root}; |
2ded1cc1 | 290 | |
35ed0d3c | 291 | my $evalsub = lexless_anon_sub($root,$strict, $expr); |
50fc18f7 | 292 | return Opcode::_safe_call_sv($root, $obj->{Mask}, $evalsub); |
2ded1cc1 | 293 | } |
294 | ||
295 | sub rdo { | |
296 | my ($obj, $file) = @_; | |
50fc18f7 JH |
297 | my $root = $obj->{Root}; |
298 | ||
299 | my $evalsub = eval | |
d00660f4 | 300 | sprintf('package %s; sub { @_ = (); do $file }', $root); |
50fc18f7 | 301 | return Opcode::_safe_call_sv($root, $obj->{Mask}, $evalsub); |
2ded1cc1 | 302 | } |
303 | ||
304 | ||
305 | 1; | |
306 | ||
3e92a254 | 307 | __END__ |
2ded1cc1 | 308 | |
309 | =head1 NAME | |
310 | ||
311 | Safe - Compile and execute code in restricted compartments | |
312 | ||
313 | =head1 SYNOPSIS | |
314 | ||
315 | use Safe; | |
316 | ||
317 | $compartment = new Safe; | |
318 | ||
319 | $compartment->permit(qw(time sort :browse)); | |
320 | ||
321 | $result = $compartment->reval($unsafe_code); | |
322 | ||
323 | =head1 DESCRIPTION | |
324 | ||
325 | The Safe extension module allows the creation of compartments | |
326 | in which perl code can be evaluated. Each compartment has | |
327 | ||
328 | =over 8 | |
329 | ||
330 | =item a new namespace | |
331 | ||
332 | The "root" of the namespace (i.e. "main::") is changed to a | |
333 | different package and code evaluated in the compartment cannot | |
334 | refer to variables outside this namespace, even with run-time | |
335 | glob lookups and other tricks. | |
336 | ||
337 | Code which is compiled outside the compartment can choose to place | |
338 | variables into (or I<share> variables with) the compartment's namespace | |
339 | and only that data will be visible to code evaluated in the | |
340 | compartment. | |
341 | ||
342 | By default, the only variables shared with compartments are the | |
343 | "underscore" variables $_ and @_ (and, technically, the less frequently | |
344 | used %_, the _ filehandle and so on). This is because otherwise perl | |
345 | operators which default to $_ will not work and neither will the | |
346 | assignment of arguments to @_ on subroutine entry. | |
347 | ||
348 | =item an operator mask | |
349 | ||
350 | Each compartment has an associated "operator mask". Recall that | |
351 | perl code is compiled into an internal format before execution. | |
352 | Evaluating perl code (e.g. via "eval" or "do 'file'") causes | |
353 | the code to be compiled into an internal format and then, | |
354 | provided there was no error in the compilation, executed. | |
f610777f A |
355 | Code evaluated in a compartment compiles subject to the |
356 | compartment's operator mask. Attempting to evaluate code in a | |
2ded1cc1 | 357 | compartment which contains a masked operator will cause the |
358 | compilation to fail with an error. The code will not be executed. | |
359 | ||
360 | The default operator mask for a newly created compartment is | |
361 | the ':default' optag. | |
362 | ||
86780939 | 363 | It is important that you read the L<Opcode> module documentation |
1fef88e7 | 364 | for more information, especially for detailed definitions of opnames, |
2ded1cc1 | 365 | optags and opsets. |
366 | ||
367 | Since it is only at the compilation stage that the operator mask | |
368 | applies, controlled access to potentially unsafe operations can | |
369 | be achieved by having a handle to a wrapper subroutine (written | |
370 | outside the compartment) placed into the compartment. For example, | |
371 | ||
372 | $cpt = new Safe; | |
373 | sub wrapper { | |
374 | # vet arguments and perform potentially unsafe operations | |
375 | } | |
376 | $cpt->share('&wrapper'); | |
377 | ||
378 | =back | |
379 | ||
380 | ||
381 | =head1 WARNING | |
382 | ||
383 | The authors make B<no warranty>, implied or otherwise, about the | |
384 | suitability of this software for safety or security purposes. | |
385 | ||
386 | The authors shall not in any case be liable for special, incidental, | |
387 | consequential, indirect or other similar damages arising from the use | |
388 | of this software. | |
389 | ||
390 | Your mileage will vary. If in any doubt B<do not use it>. | |
391 | ||
392 | ||
393 | =head2 RECENT CHANGES | |
394 | ||
395 | The interface to the Safe module has changed quite dramatically since | |
396 | version 1 (as supplied with Perl5.002). Study these pages carefully if | |
397 | you have code written to use Safe version 1 because you will need to | |
398 | makes changes. | |
399 | ||
400 | ||
401 | =head2 Methods in class Safe | |
402 | ||
403 | To create a new compartment, use | |
404 | ||
405 | $cpt = new Safe; | |
406 | ||
407 | Optional argument is (NAMESPACE), where NAMESPACE is the root namespace | |
408 | to use for the compartment (defaults to "Safe::Root0", incremented for | |
409 | each new compartment). | |
410 | ||
411 | Note that version 1.00 of the Safe module supported a second optional | |
412 | parameter, MASK. That functionality has been withdrawn pending deeper | |
413 | consideration. Use the permit and deny methods described below. | |
414 | ||
415 | The following methods can then be used on the compartment | |
416 | object returned by the above constructor. The object argument | |
417 | is implicit in each case. | |
418 | ||
419 | ||
420 | =over 8 | |
421 | ||
422 | =item permit (OP, ...) | |
423 | ||
424 | Permit the listed operators to be used when compiling code in the | |
425 | compartment (in I<addition> to any operators already permitted). | |
426 | ||
86f9b3f5 RGS |
427 | You can list opcodes by names, or use a tag name; see |
428 | L<Opcode/"Predefined Opcode Tags">. | |
429 | ||
2ded1cc1 | 430 | =item permit_only (OP, ...) |
431 | ||
432 | Permit I<only> the listed operators to be used when compiling code in | |
433 | the compartment (I<no> other operators are permitted). | |
434 | ||
435 | =item deny (OP, ...) | |
436 | ||
437 | Deny the listed operators from being used when compiling code in the | |
438 | compartment (other operators may still be permitted). | |
439 | ||
440 | =item deny_only (OP, ...) | |
441 | ||
442 | Deny I<only> the listed operators from being used when compiling code | |
443 | in the compartment (I<all> other operators will be permitted). | |
444 | ||
445 | =item trap (OP, ...) | |
446 | ||
447 | =item untrap (OP, ...) | |
448 | ||
449 | The trap and untrap methods are synonyms for deny and permit | |
450 | respectfully. | |
451 | ||
452 | =item share (NAME, ...) | |
453 | ||
454 | This shares the variable(s) in the argument list with the compartment. | |
5f944aa8 | 455 | This is almost identical to exporting variables using the L<Exporter> |
2ded1cc1 | 456 | module. |
457 | ||
5c3cfe29 SR |
458 | Each NAME must be the B<name> of a non-lexical variable, typically |
459 | with the leading type identifier included. A bareword is treated as a | |
460 | function name. | |
2ded1cc1 | 461 | |
462 | Examples of legal names are '$foo' for a scalar, '@foo' for an | |
463 | array, '%foo' for a hash, '&foo' or 'foo' for a subroutine and '*foo' | |
464 | for a glob (i.e. all symbol table entries associated with "foo", | |
465 | including scalar, array, hash, sub and filehandle). | |
466 | ||
467 | Each NAME is assumed to be in the calling package. See share_from | |
468 | for an alternative method (which share uses). | |
469 | ||
470 | =item share_from (PACKAGE, ARRAYREF) | |
471 | ||
472 | This method is similar to share() but allows you to explicitly name the | |
473 | package that symbols should be shared from. The symbol names (including | |
474 | type characters) are supplied as an array reference. | |
475 | ||
476 | $safe->share_from('main', [ '$foo', '%bar', 'func' ]); | |
477 | ||
478 | ||
479 | =item varglob (VARNAME) | |
480 | ||
481 | This returns a glob reference for the symbol table entry of VARNAME in | |
482 | the package of the compartment. VARNAME must be the B<name> of a | |
483 | variable without any leading type marker. For example, | |
484 | ||
485 | $cpt = new Safe 'Root'; | |
486 | $Root::foo = "Hello world"; | |
487 | # Equivalent version which doesn't need to know $cpt's package name: | |
488 | ${$cpt->varglob('foo')} = "Hello world"; | |
489 | ||
490 | ||
fd8ebd06 | 491 | =item reval (STRING, STRICT) |
2ded1cc1 | 492 | |
493 | This evaluates STRING as perl code inside the compartment. | |
494 | ||
495 | The code can only see the compartment's namespace (as returned by the | |
496 | B<root> method). The compartment's root package appears to be the | |
497 | C<main::> package to the code inside the compartment. | |
498 | ||
499 | Any attempt by the code in STRING to use an operator which is not permitted | |
500 | by the compartment will cause an error (at run-time of the main program | |
501 | but at compile-time for the code in STRING). The error is of the form | |
cb77fdf0 | 502 | "'%s' trapped by operation mask...". |
2ded1cc1 | 503 | |
504 | If an operation is trapped in this way, then the code in STRING will | |
505 | not be executed. If such a trapped operation occurs or any other | |
506 | compile-time or return error, then $@ is set to the error message, just | |
507 | as with an eval(). | |
508 | ||
509 | If there is no error, then the method returns the value of the last | |
510 | expression evaluated, or a return statement may be used, just as with | |
511 | subroutines and B<eval()>. The context (list or scalar) is determined | |
512 | by the caller as usual. | |
513 | ||
514 | This behaviour differs from the beta distribution of the Safe extension | |
515 | where earlier versions of perl made it hard to mimic the return | |
516 | behaviour of the eval() command and the context was always scalar. | |
517 | ||
fd8ebd06 RGS |
518 | The formerly undocumented STRICT argument sets strictness: if true |
519 | 'use strict;' is used, otherwise it uses 'no strict;'. B<Note>: if | |
520 | STRICT is omitted 'no strict;' is the default. | |
521 | ||
2ded1cc1 | 522 | Some points to note: |
523 | ||
524 | If the entereval op is permitted then the code can use eval "..." to | |
525 | 'hide' code which might use denied ops. This is not a major problem | |
526 | since when the code tries to execute the eval it will fail because the | |
527 | opmask is still in effect. However this technique would allow clever, | |
528 | and possibly harmful, code to 'probe' the boundaries of what is | |
529 | possible. | |
530 | ||
531 | Any string eval which is executed by code executing in a compartment, | |
532 | or by code called from code executing in a compartment, will be eval'd | |
533 | in the namespace of the compartment. This is potentially a serious | |
534 | problem. | |
535 | ||
536 | Consider a function foo() in package pkg compiled outside a compartment | |
537 | but shared with it. Assume the compartment has a root package called | |
1fef88e7 | 538 | 'Root'. If foo() contains an eval statement like eval '$foo = 1' then, |
2ded1cc1 | 539 | normally, $pkg::foo will be set to 1. If foo() is called from the |
540 | compartment (by whatever means) then instead of setting $pkg::foo, the | |
541 | eval will actually set $Root::pkg::foo. | |
542 | ||
543 | This can easily be demonstrated by using a module, such as the Socket | |
544 | module, which uses eval "..." as part of an AUTOLOAD function. You can | |
545 | 'use' the module outside the compartment and share an (autoloaded) | |
546 | function with the compartment. If an autoload is triggered by code in | |
547 | the compartment, or by any code anywhere that is called by any means | |
548 | from the compartment, then the eval in the Socket module's AUTOLOAD | |
549 | function happens in the namespace of the compartment. Any variables | |
550 | created or used by the eval'd code are now under the control of | |
551 | the code in the compartment. | |
552 | ||
553 | A similar effect applies to I<all> runtime symbol lookups in code | |
554 | called from a compartment but not compiled within it. | |
555 | ||
556 | ||
557 | ||
558 | =item rdo (FILENAME) | |
559 | ||
560 | This evaluates the contents of file FILENAME inside the compartment. | |
561 | See above documentation on the B<reval> method for further details. | |
562 | ||
563 | =item root (NAMESPACE) | |
564 | ||
565 | This method returns the name of the package that is the root of the | |
566 | compartment's namespace. | |
567 | ||
568 | Note that this behaviour differs from version 1.00 of the Safe module | |
569 | where the root module could be used to change the namespace. That | |
570 | functionality has been withdrawn pending deeper consideration. | |
571 | ||
572 | =item mask (MASK) | |
573 | ||
574 | This is a get-or-set method for the compartment's operator mask. | |
575 | ||
576 | With no MASK argument present, it returns the current operator mask of | |
577 | the compartment. | |
578 | ||
579 | With the MASK argument present, it sets the operator mask for the | |
580 | compartment (equivalent to calling the deny_only method). | |
581 | ||
582 | =back | |
583 | ||
584 | ||
585 | =head2 Some Safety Issues | |
586 | ||
587 | This section is currently just an outline of some of the things code in | |
588 | a compartment might do (intentionally or unintentionally) which can | |
589 | have an effect outside the compartment. | |
590 | ||
591 | =over 8 | |
592 | ||
593 | =item Memory | |
594 | ||
595 | Consuming all (or nearly all) available memory. | |
596 | ||
597 | =item CPU | |
598 | ||
599 | Causing infinite loops etc. | |
600 | ||
601 | =item Snooping | |
602 | ||
603 | Copying private information out of your system. Even something as | |
604 | simple as your user name is of value to others. Much useful information | |
605 | could be gleaned from your environment variables for example. | |
606 | ||
607 | =item Signals | |
608 | ||
609 | Causing signals (especially SIGFPE and SIGALARM) to affect your process. | |
610 | ||
611 | Setting up a signal handler will need to be carefully considered | |
612 | and controlled. What mask is in effect when a signal handler | |
613 | gets called? If a user can get an imported function to get an | |
614 | exception and call the user's signal handler, does that user's | |
615 | restricted mask get re-instated before the handler is called? | |
616 | Does an imported handler get called with its original mask or | |
617 | the user's one? | |
618 | ||
619 | =item State Changes | |
620 | ||
621 | Ops such as chdir obviously effect the process as a whole and not just | |
622 | the code in the compartment. Ops such as rand and srand have a similar | |
623 | but more subtle effect. | |
624 | ||
625 | =back | |
626 | ||
627 | =head2 AUTHOR | |
628 | ||
25ff8439 | 629 | Originally designed and implemented by Malcolm Beattie. |
2ded1cc1 | 630 | |
25ff8439 RGS |
631 | Reworked to use the Opcode module and other changes added by Tim Bunce. |
632 | ||
633 | Currently maintained by the Perl 5 Porters, <perl5-porters@perl.org>. | |
2ded1cc1 | 634 | |
635 | =cut | |
636 |