Commit | Line | Data |
---|---|---|
6badd1a5 | 1 | package Opcode; |
2 | ||
3 | require 5.002; | |
4 | ||
137443ea | 5 | use vars qw($VERSION $XS_VERSION @ISA @EXPORT_OK); |
6badd1a5 | 6 | |
8903cb82 | 7 | $VERSION = "1.04"; |
e858de61 | 8 | $XS_VERSION = "1.03"; |
6badd1a5 | 9 | |
10 | use strict; | |
11 | use Carp; | |
12 | use Exporter (); | |
13 | use DynaLoader (); | |
14 | @ISA = qw(Exporter DynaLoader); | |
15 | ||
16 | BEGIN { | |
17 | @EXPORT_OK = qw( | |
18 | opset ops_to_opset | |
19 | opset_to_ops opset_to_hex invert_opset | |
20 | empty_opset full_opset | |
21 | opdesc opcodes opmask define_optag | |
22 | opmask_add verify_opset opdump | |
23 | ); | |
24 | } | |
25 | ||
68dc0745 | 26 | sub opset (;@); |
27 | sub opset_to_hex ($); | |
28 | sub opdump (;$); | |
6badd1a5 | 29 | use subs @EXPORT_OK; |
30 | ||
137443ea | 31 | bootstrap Opcode $XS_VERSION; |
6badd1a5 | 32 | |
33 | _init_optags(); | |
34 | ||
68dc0745 | 35 | sub ops_to_opset { opset @_ } # alias for old name |
6badd1a5 | 36 | |
37 | sub opset_to_hex ($) { | |
38 | return "(invalid opset)" unless verify_opset($_[0]); | |
39 | unpack("h*",$_[0]); | |
40 | } | |
41 | ||
42 | sub opdump (;$) { | |
43 | my $pat = shift; | |
44 | # handy utility: perl -MOpcode=opdump -e 'opdump File' | |
45 | foreach(opset_to_ops(full_opset)) { | |
46 | my $op = sprintf " %12s %s\n", $_, opdesc($_); | |
47 | next if defined $pat and $op !~ m/$pat/i; | |
48 | print $op; | |
49 | } | |
50 | } | |
51 | ||
52 | ||
53 | ||
54 | sub _init_optags { | |
55 | my(%all, %seen); | |
56 | @all{opset_to_ops(full_opset)} = (); # keys only | |
57 | ||
7a57407b | 58 | local($_); |
6badd1a5 | 59 | local($/) = "\n=cut"; # skip to optags definition section |
60 | <DATA>; | |
61 | $/ = "\n="; # now read in 'pod section' chunks | |
62 | while(<DATA>) { | |
63 | next unless m/^item\s+(:\w+)/; | |
64 | my $tag = $1; | |
65 | ||
66 | # Split into lines, keep only indented lines | |
67 | my @lines = grep { m/^\s/ } split(/\n/); | |
68 | foreach (@lines) { s/--.*// } # delete comments | |
69 | my @ops = map { split ' ' } @lines; # get op words | |
70 | ||
71 | foreach(@ops) { | |
72 | warn "$tag - $_ already tagged in $seen{$_}\n" if $seen{$_}; | |
73 | $seen{$_} = $tag; | |
74 | delete $all{$_}; | |
75 | } | |
76 | # opset will croak on invalid names | |
77 | define_optag($tag, opset(@ops)); | |
78 | } | |
79 | close(DATA); | |
80 | warn "Untagged opnames: ".join(' ',keys %all)."\n" if %all; | |
81 | } | |
82 | ||
83 | ||
84 | 1; | |
85 | ||
86 | __DATA__ | |
87 | ||
88 | =head1 NAME | |
89 | ||
90 | Opcode - Disable named opcodes when compiling perl code | |
91 | ||
92 | =head1 SYNOPSIS | |
93 | ||
94 | use Opcode; | |
95 | ||
96 | ||
97 | =head1 DESCRIPTION | |
98 | ||
99 | Perl code is always compiled into an internal format before execution. | |
100 | ||
101 | Evaluating perl code (e.g. via "eval" or "do 'file'") causes | |
102 | the code to be compiled into an internal format and then, | |
103 | provided there was no error in the compilation, executed. | |
104 | The internal format is based on many distinct I<opcodes>. | |
105 | ||
106 | By default no opmask is in effect and any code can be compiled. | |
107 | ||
108 | The Opcode module allow you to define an I<operator mask> to be in | |
109 | effect when perl I<next> compiles any code. Attempting to compile code | |
110 | which contains a masked opcode will cause the compilation to fail | |
111 | with an error. The code will not be executed. | |
112 | ||
113 | =head1 NOTE | |
114 | ||
115 | The Opcode module is not usually used directly. See the ops pragma and | |
116 | Safe modules for more typical uses. | |
117 | ||
118 | =head1 WARNING | |
119 | ||
120 | The authors make B<no warranty>, implied or otherwise, about the | |
121 | suitability of this software for safety or security purposes. | |
122 | ||
123 | The authors shall not in any case be liable for special, incidental, | |
124 | consequential, indirect or other similar damages arising from the use | |
125 | of this software. | |
126 | ||
127 | Your mileage will vary. If in any doubt B<do not use it>. | |
128 | ||
129 | ||
130 | =head1 Operator Names and Operator Lists | |
131 | ||
132 | The canonical list of operator names is the contents of the array | |
4369b173 | 133 | PL_op_name defined and initialised in file F<opcode.h> of the Perl |
6badd1a5 | 134 | source distribution (and installed into the perl library). |
135 | ||
136 | Each operator has both a terse name (its opname) and a more verbose or | |
137 | recognisable descriptive name. The opdesc function can be used to | |
138 | return a list of descriptions for a list of operators. | |
139 | ||
140 | Many of the functions and methods listed below take a list of | |
141 | operators as parameters. Most operator lists can be made up of several | |
142 | types of element. Each element can be one of | |
143 | ||
144 | =over 8 | |
145 | ||
146 | =item an operator name (opname) | |
147 | ||
148 | Operator names are typically small lowercase words like enterloop, | |
149 | leaveloop, last, next, redo etc. Sometimes they are rather cryptic | |
150 | like gv2cv, i_ncmp and ftsvtx. | |
151 | ||
152 | =item an operator tag name (optag) | |
153 | ||
154 | Operator tags can be used to refer to groups (or sets) of operators. | |
7b8d334a | 155 | Tag names always begin with a colon. The Opcode module defines several |
6badd1a5 | 156 | optags and the user can define others using the define_optag function. |
157 | ||
158 | =item a negated opname or optag | |
159 | ||
160 | An opname or optag can be prefixed with an exclamation mark, e.g., !mkdir. | |
161 | Negating an opname or optag means remove the corresponding ops from the | |
162 | accumulated set of ops at that point. | |
163 | ||
164 | =item an operator set (opset) | |
165 | ||
166 | An I<opset> as a binary string of approximately 43 bytes which holds a | |
167 | set or zero or more operators. | |
168 | ||
169 | The opset and opset_to_ops functions can be used to convert from | |
170 | a list of operators to an opset and I<vice versa>. | |
171 | ||
172 | Wherever a list of operators can be given you can use one or more opsets. | |
173 | See also Manipulating Opsets below. | |
174 | ||
175 | =back | |
176 | ||
177 | ||
178 | =head1 Opcode Functions | |
179 | ||
180 | The Opcode package contains functions for manipulating operator names | |
181 | tags and sets. All are available for export by the package. | |
182 | ||
183 | =over 8 | |
184 | ||
185 | =item opcodes | |
186 | ||
187 | In a scalar context opcodes returns the number of opcodes in this | |
188 | version of perl (around 340 for perl5.002). | |
189 | ||
190 | In a list context it returns a list of all the operator names. | |
191 | (Not yet implemented, use @names = opset_to_ops(full_opset).) | |
192 | ||
193 | =item opset (OP, ...) | |
194 | ||
195 | Returns an opset containing the listed operators. | |
196 | ||
197 | =item opset_to_ops (OPSET) | |
198 | ||
199 | Returns a list of operator names corresponding to those operators in | |
200 | the set. | |
201 | ||
202 | =item opset_to_hex (OPSET) | |
203 | ||
204 | Returns a string representation of an opset. Can be handy for debugging. | |
205 | ||
206 | =item full_opset | |
207 | ||
208 | Returns an opset which includes all operators. | |
209 | ||
210 | =item empty_opset | |
211 | ||
212 | Returns an opset which contains no operators. | |
213 | ||
214 | =item invert_opset (OPSET) | |
215 | ||
216 | Returns an opset which is the inverse set of the one supplied. | |
217 | ||
218 | =item verify_opset (OPSET, ...) | |
219 | ||
220 | Returns true if the supplied opset looks like a valid opset (is the | |
221 | right length etc) otherwise it returns false. If an optional second | |
222 | parameter is true then verify_opset will croak on an invalid opset | |
223 | instead of returning false. | |
224 | ||
225 | Most of the other Opcode functions call verify_opset automatically | |
226 | and will croak if given an invalid opset. | |
227 | ||
228 | =item define_optag (OPTAG, OPSET) | |
229 | ||
230 | Define OPTAG as a symbolic name for OPSET. Optag names always start | |
231 | with a colon C<:>. | |
232 | ||
233 | The optag name used must not be defined already (define_optag will | |
234 | croak if it is already defined). Optag names are global to the perl | |
235 | process and optag definitions cannot be altered or deleted once | |
236 | defined. | |
237 | ||
238 | It is strongly recommended that applications using Opcode should use a | |
239 | leading capital letter on their tag names since lowercase names are | |
240 | reserved for use by the Opcode module. If using Opcode within a module | |
241 | you should prefix your tags names with the name of your module to | |
242 | ensure uniqueness and thus avoid clashes with other modules. | |
243 | ||
244 | =item opmask_add (OPSET) | |
245 | ||
246 | Adds the supplied opset to the current opmask. Note that there is | |
247 | currently I<no> mechanism for unmasking ops once they have been masked. | |
248 | This is intentional. | |
249 | ||
250 | =item opmask | |
251 | ||
252 | Returns an opset corresponding to the current opmask. | |
253 | ||
254 | =item opdesc (OP, ...) | |
255 | ||
256 | This takes a list of operator names and returns the corresponding list | |
257 | of operator descriptions. | |
258 | ||
259 | =item opdump (PAT) | |
260 | ||
261 | Dumps to STDOUT a two column list of op names and op descriptions. | |
262 | If an optional pattern is given then only lines which match the | |
263 | (case insensitive) pattern will be output. | |
264 | ||
265 | It's designed to be used as a handy command line utility: | |
266 | ||
267 | perl -MOpcode=opdump -e opdump | |
268 | perl -MOpcode=opdump -e 'opdump Eval' | |
269 | ||
270 | =back | |
271 | ||
272 | =head1 Manipulating Opsets | |
273 | ||
274 | Opsets may be manipulated using the perl bit vector operators & (and), | (or), | |
275 | ^ (xor) and ~ (negate/invert). | |
276 | ||
277 | However you should never rely on the numerical position of any opcode | |
278 | within the opset. In other words both sides of a bit vector operator | |
279 | should be opsets returned from Opcode functions. | |
280 | ||
281 | Also, since the number of opcodes in your current version of perl might | |
282 | not be an exact multiple of eight, there may be unused bits in the last | |
283 | byte of an upset. This should not cause any problems (Opcode functions | |
284 | ignore those extra bits) but it does mean that using the ~ operator | |
285 | will typically not produce the same 'physical' opset 'string' as the | |
286 | invert_opset function. | |
287 | ||
288 | ||
289 | =head1 TO DO (maybe) | |
290 | ||
291 | $bool = opset_eq($opset1, $opset2) true if opsets are logically eqiv | |
292 | ||
293 | $yes = opset_can($opset, @ops) true if $opset has all @ops set | |
294 | ||
295 | @diff = opset_diff($opset1, $opset2) => ('foo', '!bar', ...) | |
296 | ||
297 | =cut | |
298 | ||
299 | # the =cut above is used by _init_optags() to get here quickly | |
300 | ||
301 | =head1 Predefined Opcode Tags | |
302 | ||
303 | =over 5 | |
304 | ||
305 | =item :base_core | |
306 | ||
307 | null stub scalar pushmark wantarray const defined undef | |
308 | ||
309 | rv2sv sassign | |
310 | ||
311 | rv2av aassign aelem aelemfast aslice av2arylen | |
312 | ||
313 | rv2hv helem hslice each values keys exists delete | |
314 | ||
315 | preinc i_preinc predec i_predec postinc i_postinc postdec i_postdec | |
316 | int hex oct abs pow multiply i_multiply divide i_divide | |
317 | modulo i_modulo add i_add subtract i_subtract | |
318 | ||
319 | left_shift right_shift bit_and bit_xor bit_or negate i_negate | |
320 | not complement | |
321 | ||
322 | lt i_lt gt i_gt le i_le ge i_ge eq i_eq ne i_ne ncmp i_ncmp | |
323 | slt sgt sle sge seq sne scmp | |
324 | ||
325 | substr vec stringify study pos length index rindex ord chr | |
326 | ||
327 | ucfirst lcfirst uc lc quotemeta trans chop schop chomp schomp | |
328 | ||
8782bef2 | 329 | match split qr |
6badd1a5 | 330 | |
331 | list lslice splice push pop shift unshift reverse | |
332 | ||
333 | cond_expr flip flop andassign orassign and or xor | |
334 | ||
7399586d | 335 | warn die lineseq nextstate scope enter leave setstate |
6badd1a5 | 336 | |
337 | rv2cv anoncode prototype | |
338 | ||
f5d5a27c | 339 | entersub leavesub return method method_named -- XXX loops via recursion? |
6badd1a5 | 340 | |
341 | leaveeval -- needed for Safe to operate, is safe without entereval | |
342 | ||
343 | =item :base_mem | |
344 | ||
345 | These memory related ops are not included in :base_core because they | |
346 | can easily be used to implement a resource attack (e.g., consume all | |
347 | available memory). | |
348 | ||
349 | concat repeat join range | |
350 | ||
351 | anonlist anonhash | |
352 | ||
353 | Note that despite the existance of this optag a memory resource attack | |
354 | may still be possible using only :base_core ops. | |
355 | ||
356 | Disabling these ops is a I<very> heavy handed way to attempt to prevent | |
357 | a memory resource attack. It's probable that a specific memory limit | |
358 | mechanism will be added to perl in the near future. | |
359 | ||
360 | =item :base_loop | |
361 | ||
362 | These loop ops are not included in :base_core because they can easily be | |
363 | used to implement a resource attack (e.g., consume all available CPU time). | |
364 | ||
365 | grepstart grepwhile | |
366 | mapstart mapwhile | |
367 | enteriter iter | |
e897d888 | 368 | enterloop leaveloop unstack |
6badd1a5 | 369 | last next redo |
370 | goto | |
371 | ||
372 | =item :base_io | |
373 | ||
374 | These ops enable I<filehandle> (rather than filename) based input and | |
375 | output. These are safe on the assumption that only pre-existing | |
376 | filehandles are available for use. To create new filehandles other ops | |
377 | such as open would need to be enabled. | |
378 | ||
379 | readline rcatline getc read | |
380 | ||
381 | formline enterwrite leavewrite | |
382 | ||
96e4d5b1 | 383 | print sysread syswrite send recv |
384 | ||
8903cb82 | 385 | eof tell seek sysseek |
6badd1a5 | 386 | |
387 | readdir telldir seekdir rewinddir | |
388 | ||
389 | =item :base_orig | |
390 | ||
391 | These are a hotchpotch of opcodes still waiting to be considered | |
392 | ||
393 | gvsv gv gelem | |
394 | ||
395 | padsv padav padhv padany | |
396 | ||
397 | rv2gv refgen srefgen ref | |
398 | ||
399 | bless -- could be used to change ownership of objects (reblessing) | |
400 | ||
2cd61cdb | 401 | pushre regcmaybe regcreset regcomp subst substcont |
6badd1a5 | 402 | |
403 | sprintf prtf -- can core dump | |
404 | ||
405 | crypt | |
406 | ||
407 | tie untie | |
408 | ||
409 | dbmopen dbmclose | |
410 | sselect select | |
411 | pipe_op sockpair | |
412 | ||
413 | getppid getpgrp setpgrp getpriority setpriority localtime gmtime | |
414 | ||
415 | entertry leavetry -- can be used to 'hide' fatal errors | |
416 | ||
417 | =item :base_math | |
418 | ||
419 | These ops are not included in :base_core because of the risk of them being | |
420 | used to generate floating point exceptions (which would have to be caught | |
421 | using a $SIG{FPE} handler). | |
422 | ||
423 | atan2 sin cos exp log sqrt | |
424 | ||
425 | These ops are not included in :base_core because they have an effect | |
426 | beyond the scope of the compartment. | |
427 | ||
428 | rand srand | |
429 | ||
1f5895a1 MB |
430 | =item :base_thread |
431 | ||
554b3eca | 432 | These ops are related to multi-threading. |
1f5895a1 | 433 | |
2faa37cc | 434 | lock threadsv |
1f5895a1 | 435 | |
6badd1a5 | 436 | =item :default |
437 | ||
438 | A handy tag name for a I<reasonable> default set of ops. (The current ops | |
439 | allowed are unstable while development continues. It will change.) | |
440 | ||
5ddb6eab | 441 | :base_core :base_mem :base_loop :base_io :base_orig :base_thread |
6badd1a5 | 442 | |
443 | If safety matters to you (and why else would you be using the Opcode module?) | |
444 | then you should not rely on the definition of this, or indeed any other, optag! | |
445 | ||
446 | ||
447 | =item :filesys_read | |
448 | ||
449 | stat lstat readlink | |
450 | ||
451 | ftatime ftblk ftchr ftctime ftdir fteexec fteowned fteread | |
452 | ftewrite ftfile ftis ftlink ftmtime ftpipe ftrexec ftrowned | |
453 | ftrread ftsgid ftsize ftsock ftsuid fttty ftzero ftrwrite ftsvtx | |
454 | ||
455 | fttext ftbinary | |
456 | ||
457 | fileno | |
458 | ||
459 | =item :sys_db | |
460 | ||
461 | ghbyname ghbyaddr ghostent shostent ehostent -- hosts | |
462 | gnbyname gnbyaddr gnetent snetent enetent -- networks | |
463 | gpbyname gpbynumber gprotoent sprotoent eprotoent -- protocols | |
464 | gsbyname gsbyport gservent sservent eservent -- services | |
465 | ||
466 | gpwnam gpwuid gpwent spwent epwent getlogin -- users | |
467 | ggrnam ggrgid ggrent sgrent egrent -- groups | |
468 | ||
469 | =item :browse | |
470 | ||
471 | A handy tag name for a I<reasonable> default set of ops beyond the | |
472 | :default optag. Like :default (and indeed all the other optags) its | |
473 | current definition is unstable while development continues. It will change. | |
474 | ||
475 | The :browse tag represents the next step beyond :default. It it a | |
476 | superset of the :default ops and adds :filesys_read the :sys_db. | |
477 | The intent being that scripts can access more (possibly sensitive) | |
478 | information about your system but not be able to change it. | |
479 | ||
480 | :default :filesys_read :sys_db | |
481 | ||
482 | =item :filesys_open | |
483 | ||
484 | sysopen open close | |
485 | umask binmode | |
486 | ||
487 | open_dir closedir -- other dir ops are in :base_io | |
488 | ||
489 | =item :filesys_write | |
490 | ||
491 | link unlink rename symlink truncate | |
492 | ||
493 | mkdir rmdir | |
494 | ||
495 | utime chmod chown | |
496 | ||
497 | fcntl -- not strictly filesys related, but possibly as dangerous? | |
498 | ||
499 | =item :subprocess | |
500 | ||
501 | backtick system | |
502 | ||
503 | fork | |
504 | ||
505 | wait waitpid | |
506 | ||
f812a825 | 507 | glob -- access to Cshell via <`rm *`> |
508 | ||
6badd1a5 | 509 | =item :ownprocess |
510 | ||
511 | exec exit kill | |
512 | ||
513 | time tms -- could be used for timing attacks (paranoid?) | |
514 | ||
515 | =item :others | |
516 | ||
517 | This tag holds groups of assorted specialist opcodes that don't warrant | |
518 | having optags defined for them. | |
519 | ||
520 | SystemV Interprocess Communications: | |
521 | ||
522 | msgctl msgget msgrcv msgsnd | |
523 | ||
524 | semctl semget semop | |
525 | ||
526 | shmctl shmget shmread shmwrite | |
527 | ||
528 | =item :still_to_be_decided | |
529 | ||
530 | chdir | |
531 | flock ioctl | |
532 | ||
533 | socket getpeername ssockopt | |
534 | bind connect listen accept shutdown gsockopt getsockname | |
535 | ||
536 | sleep alarm -- changes global timer state and signal handling | |
537 | sort -- assorted problems including core dumps | |
538 | tied -- can be used to access object implementing a tie | |
539 | pack unpack -- can be used to create/use memory pointers | |
540 | ||
541 | entereval -- can be used to hide code from initial compile | |
542 | require dofile | |
543 | ||
544 | caller -- get info about calling environment and args | |
545 | ||
546 | reset | |
547 | ||
548 | dbstate -- perl -d version of nextstate(ment) opcode | |
549 | ||
550 | =item :dangerous | |
551 | ||
552 | This tag is simply a bucket for opcodes that are unlikely to be used via | |
553 | a tag name but need to be tagged for completness and documentation. | |
554 | ||
555 | syscall dump chroot | |
556 | ||
557 | ||
558 | =back | |
559 | ||
560 | =head1 SEE ALSO | |
561 | ||
562 | ops(3) -- perl pragma interface to Opcode module. | |
563 | ||
564 | Safe(3) -- Opcode and namespace limited execution compartments | |
565 | ||
566 | =head1 AUTHORS | |
567 | ||
568 | Originally designed and implemented by Malcolm Beattie, | |
569 | mbeattie@sable.ox.ac.uk as part of Safe version 1. | |
570 | ||
571 | Split out from Safe module version 1, named opcode tags and other | |
7b8d334a | 572 | changes added by Tim Bunce. |
6badd1a5 | 573 | |
574 | =cut | |
575 |