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12724 update smatch to 0.6.1-rc1-il-5
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--- old/usr/src/tools/smatch/src/smatch_kernel_user_data.c
+++ new/usr/src/tools/smatch/src/smatch_kernel_user_data.c
1 1 /*
2 2 * Copyright (C) 2011 Dan Carpenter.
3 3 *
4 4 * This program is free software; you can redistribute it and/or
5 5 * modify it under the terms of the GNU General Public License
6 6 * as published by the Free Software Foundation; either version 2
7 7 * of the License, or (at your option) any later version.
8 8 *
9 9 * This program is distributed in the hope that it will be useful,
10 10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 12 * GNU General Public License for more details.
13 13 *
14 14 * You should have received a copy of the GNU General Public License
15 15 * along with this program; if not, see http://www.gnu.org/copyleft/gpl.txt
16 16 */
17 17
18 18 /*
19 19 * There are a couple checks that try to see if a variable
20 20 * comes from the user. It would be better to unify them
21 21 * into one place. Also it we should follow the data down
22 22 * the call paths. Hence this file.
23 23 */
24 24
25 25 #include "smatch.h"
26 26 #include "smatch_slist.h"
27 27 #include "smatch_extra.h"
28 28
29 29 static int my_id;
30 30 static int my_call_id;
31 31
32 32 STATE(called);
33 33 static bool func_gets_user_data;
34 34
35 35 static const char *kstr_funcs[] = {
36 36 "kstrtoull", "kstrtoll", "kstrtoul", "kstrtol", "kstrtouint",
37 37 "kstrtoint", "kstrtou64", "kstrtos64", "kstrtou32", "kstrtos32",
38 38 "kstrtou16", "kstrtos16", "kstrtou8", "kstrtos8", "kstrtoull_from_user"
39 39 "kstrtoll_from_user", "kstrtoul_from_user", "kstrtol_from_user",
40 40 "kstrtouint_from_user", "kstrtoint_from_user", "kstrtou16_from_user",
41 41 "kstrtos16_from_user", "kstrtou8_from_user", "kstrtos8_from_user",
42 42 "kstrtou64_from_user", "kstrtos64_from_user", "kstrtou32_from_user",
43 43 "kstrtos32_from_user",
44 44 };
45 45
46 46 static const char *returns_user_data[] = {
47 47 "simple_strtol", "simple_strtoll", "simple_strtoul", "simple_strtoull",
48 48 "kvm_register_read",
49 49 };
50 50
51 51 static const char *returns_pointer_to_user_data[] = {
52 52 "nlmsg_data", "nla_data", "memdup_user", "kmap_atomic", "skb_network_header",
53 53 };
54 54
55 55 static void set_points_to_user_data(struct expression *expr);
56 56
57 57 static struct stree *start_states;
58 58 static struct stree_stack *saved_stack;
59 59 static void save_start_states(struct statement *stmt)
60 60 {
61 61 start_states = clone_stree(__get_cur_stree());
62 62 }
63 63
64 64 static void free_start_states(void)
65 65 {
66 66 free_stree(&start_states);
67 67 }
68 68
69 69 static void match_save_states(struct expression *expr)
70 70 {
71 71 push_stree(&saved_stack, start_states);
72 72 start_states = NULL;
73 73 }
74 74
75 75 static void match_restore_states(struct expression *expr)
76 76 {
77 77 free_stree(&start_states);
78 78 start_states = pop_stree(&saved_stack);
79 79 }
80 80
81 81 static struct smatch_state *empty_state(struct sm_state *sm)
82 82 {
83 83 return alloc_estate_empty();
84 84 }
85 85
86 86 static void pre_merge_hook(struct sm_state *cur, struct sm_state *other)
87 87 {
88 88 struct smatch_state *user = cur->state;
89 89 struct smatch_state *extra;
90 90 struct smatch_state *state;
91 91 struct range_list *rl;
92 92
93 93 extra = __get_state(SMATCH_EXTRA, cur->name, cur->sym);
94 94 if (!extra)
95 95 return;
96 96 rl = rl_intersection(estate_rl(user), estate_rl(extra));
97 97 state = alloc_estate_rl(clone_rl(rl));
98 98 if (estate_capped(user) || is_capped_var_sym(cur->name, cur->sym))
99 99 estate_set_capped(state);
100 100 if (estate_treat_untagged(user))
101 101 estate_set_treat_untagged(state);
102 102 set_state(my_id, cur->name, cur->sym, state);
103 103 }
104 104
105 105 static void extra_nomod_hook(const char *name, struct symbol *sym, struct expression *expr, struct smatch_state *state)
106 106 {
107 107 struct smatch_state *user, *new;
108 108 struct range_list *rl;
109 109
110 110 user = __get_state(my_id, name, sym);
111 111 if (!user)
112 112 return;
113 113 rl = rl_intersection(estate_rl(user), estate_rl(state));
114 114 if (rl_equiv(rl, estate_rl(user)))
115 115 return;
116 116 new = alloc_estate_rl(rl);
117 117 if (estate_capped(user))
118 118 estate_set_capped(new);
119 119 if (estate_treat_untagged(user))
120 120 estate_set_treat_untagged(new);
121 121 set_state(my_id, name, sym, new);
122 122 }
123 123
124 124 static bool binop_capped(struct expression *expr)
125 125 {
126 126 struct range_list *left_rl;
127 127 int comparison;
128 128
129 129 if (expr->op == '-' && get_user_rl(expr->left, &left_rl)) {
130 130 if (user_rl_capped(expr->left))
131 131 return true;
132 132 comparison = get_comparison(expr->left, expr->right);
133 133 if (comparison && show_special(comparison)[0] == '>')
134 134 return true;
135 135 return false;
136 136 }
137 137
138 138 if (expr->op == '&' || expr->op == '%') {
139 139 if (is_capped(expr->left) || is_capped(expr->right))
140 140 return true;
141 141 if (user_rl_capped(expr->left) || user_rl_capped(expr->right))
142 142 return true;
143 143 return false;
144 144 }
145 145
146 146 if (user_rl_capped(expr->left) &&
147 147 user_rl_capped(expr->right))
148 148 return true;
149 149 return false;
150 150 }
151 151
152 152 bool user_rl_capped(struct expression *expr)
153 153 {
154 154 struct smatch_state *state;
155 155 struct range_list *rl;
156 156 sval_t sval;
157 157
158 158 expr = strip_expr(expr);
159 159 if (!expr)
160 160 return false;
161 161 if (get_value(expr, &sval))
162 162 return true;
163 163 if (expr->type == EXPR_BINOP)
164 164 return binop_capped(expr);
165 165 if ((expr->type == EXPR_PREOP || expr->type == EXPR_POSTOP) &&
166 166 (expr->op == SPECIAL_INCREMENT || expr->op == SPECIAL_DECREMENT))
167 167 return user_rl_capped(expr->unop);
168 168 state = get_state_expr(my_id, expr);
169 169 if (state)
170 170 return estate_capped(state);
171 171
172 172 if (get_user_rl(expr, &rl))
173 173 return false; /* uncapped user data */
174 174
175 175 return true; /* not actually user data */
176 176 }
177 177
178 178 bool user_rl_treat_untagged(struct expression *expr)
179 179 {
180 180 struct smatch_state *state;
181 181 struct range_list *rl;
182 182 sval_t sval;
183 183
184 184 expr = strip_expr(expr);
185 185 if (!expr)
186 186 return false;
187 187 if (get_value(expr, &sval))
188 188 return true;
189 189
190 190 state = get_state_expr(my_id, expr);
191 191 if (state)
192 192 return estate_treat_untagged(state);
193 193
194 194 if (get_user_rl(expr, &rl))
195 195 return false; /* uncapped user data */
196 196
197 197 return true; /* not actually user data */
198 198 }
199 199
200 200 static void tag_inner_struct_members(struct expression *expr, struct symbol *member)
201 201 {
202 202 struct expression *edge_member;
203 203 struct symbol *base = get_real_base_type(member);
204 204 struct symbol *tmp;
205 205
206 206 if (member->ident)
207 207 expr = member_expression(expr, '.', member->ident);
208 208
209 209 FOR_EACH_PTR(base->symbol_list, tmp) {
210 210 struct symbol *type;
211 211
212 212 type = get_real_base_type(tmp);
213 213 if (!type)
214 214 continue;
215 215
216 216 if (type->type == SYM_UNION || type->type == SYM_STRUCT) {
217 217 tag_inner_struct_members(expr, tmp);
218 218 continue;
219 219 }
220 220
221 221 if (!tmp->ident)
222 222 continue;
223 223
224 224 edge_member = member_expression(expr, '.', tmp->ident);
225 225 set_state_expr(my_id, edge_member, alloc_estate_whole(type));
226 226 } END_FOR_EACH_PTR(tmp);
227 227 }
228 228
229 229 static void tag_struct_members(struct symbol *type, struct expression *expr)
230 230 {
231 231 struct symbol *tmp;
232 232 struct expression *member;
233 233 int op = '*';
234 234
235 235 if (expr->type == EXPR_PREOP && expr->op == '&') {
236 236 expr = strip_expr(expr->unop);
237 237 op = '.';
238 238 }
239 239
240 240 FOR_EACH_PTR(type->symbol_list, tmp) {
241 241 type = get_real_base_type(tmp);
242 242 if (!type)
243 243 continue;
244 244
245 245 if (type->type == SYM_UNION || type->type == SYM_STRUCT) {
246 246 tag_inner_struct_members(expr, tmp);
247 247 continue;
248 248 }
249 249
250 250 if (!tmp->ident)
251 251 continue;
252 252
253 253 member = member_expression(expr, op, tmp->ident);
254 254 set_state_expr(my_id, member, alloc_estate_whole(get_type(member)));
255 255
256 256 if (type->type == SYM_ARRAY)
257 257 set_points_to_user_data(member);
258 258 } END_FOR_EACH_PTR(tmp);
259 259 }
260 260
261 261 static void tag_base_type(struct expression *expr)
262 262 {
263 263 if (expr->type == EXPR_PREOP && expr->op == '&')
264 264 expr = strip_expr(expr->unop);
265 265 else
266 266 expr = deref_expression(expr);
267 267 set_state_expr(my_id, expr, alloc_estate_whole(get_type(expr)));
268 268 }
269 269
270 270 static void tag_as_user_data(struct expression *expr)
271 271 {
272 272 struct symbol *type;
273 273
274 274 expr = strip_expr(expr);
275 275
276 276 type = get_type(expr);
277 277 if (!type || type->type != SYM_PTR)
278 278 return;
279 279 type = get_real_base_type(type);
280 280 if (!type)
281 281 return;
282 282 if (type == &void_ctype) {
283 283 set_state_expr(my_id, deref_expression(expr), alloc_estate_whole(&ulong_ctype));
284 284 return;
285 285 }
286 286 if (type->type == SYM_BASETYPE)
287 287 tag_base_type(expr);
288 288 if (type->type == SYM_STRUCT || type->type == SYM_UNION) {
289 289 if (expr->type != EXPR_PREOP || expr->op != '&')
290 290 expr = deref_expression(expr);
291 291 else
292 292 set_state_expr(my_id, deref_expression(expr), alloc_estate_whole(&ulong_ctype));
293 293 tag_struct_members(type, expr);
294 294 }
295 295 }
296 296
297 297 static void match_user_copy(const char *fn, struct expression *expr, void *_param)
298 298 {
299 299 int param = PTR_INT(_param);
300 300 struct expression *dest;
301 301
302 302 func_gets_user_data = true;
303 303
304 304 dest = get_argument_from_call_expr(expr->args, param);
305 305 dest = strip_expr(dest);
306 306 if (!dest)
307 307 return;
308 308 tag_as_user_data(dest);
309 309 }
310 310
311 311 static int is_dev_attr_name(struct expression *expr)
312 312 {
313 313 char *name;
314 314 int ret = 0;
315 315
316 316 name = expr_to_str(expr);
317 317 if (!name)
318 318 return 0;
319 319 if (strstr(name, "->attr.name"))
320 320 ret = 1;
321 321 free_string(name);
322 322 return ret;
323 323 }
324 324
325 325 static int ends_in_n(struct expression *expr)
326 326 {
327 327 struct string *str;
328 328
329 329 if (!expr)
330 330 return 0;
331 331 if (expr->type != EXPR_STRING || !expr->string)
332 332 return 0;
333 333
334 334 str = expr->string;
335 335 if (str->length < 3)
336 336 return 0;
337 337
338 338 if (str->data[str->length - 3] == '%' &&
339 339 str->data[str->length - 2] == 'n')
340 340 return 1;
341 341 return 0;
342 342 }
343 343
344 344 static void match_sscanf(const char *fn, struct expression *expr, void *unused)
345 345 {
346 346 struct expression *str, *format, *arg;
347 347 int i, last;
348 348
349 349 func_gets_user_data = true;
350 350
351 351 str = get_argument_from_call_expr(expr->args, 0);
352 352 if (is_dev_attr_name(str))
353 353 return;
354 354
355 355 format = get_argument_from_call_expr(expr->args, 1);
356 356 if (is_dev_attr_name(format))
357 357 return;
358 358
359 359 last = ptr_list_size((struct ptr_list *)expr->args) - 1;
360 360
361 361 i = -1;
362 362 FOR_EACH_PTR(expr->args, arg) {
363 363 i++;
364 364 if (i < 2)
365 365 continue;
366 366 if (i == last && ends_in_n(format))
367 367 continue;
368 368 tag_as_user_data(arg);
369 369 } END_FOR_EACH_PTR(arg);
370 370 }
371 371
372 372 static int is_skb_data(struct expression *expr)
373 373 {
374 374 struct symbol *sym;
375 375
376 376 if (!expr)
377 377 return 0;
378 378
379 379 if (expr->type == EXPR_BINOP && expr->op == '+')
380 380 return is_skb_data(expr->left);
381 381
382 382 expr = strip_expr(expr);
383 383 if (!expr)
384 384 return 0;
385 385 if (expr->type != EXPR_DEREF || expr->op != '.')
386 386 return 0;
387 387
388 388 if (!expr->member)
389 389 return 0;
390 390 if (strcmp(expr->member->name, "data") != 0)
391 391 return 0;
392 392
393 393 sym = expr_to_sym(expr->deref);
394 394 if (!sym)
395 395 return 0;
396 396 sym = get_real_base_type(sym);
397 397 if (!sym || sym->type != SYM_PTR)
398 398 return 0;
399 399 sym = get_real_base_type(sym);
400 400 if (!sym || sym->type != SYM_STRUCT || !sym->ident)
401 401 return 0;
402 402 if (strcmp(sym->ident->name, "sk_buff") != 0)
403 403 return 0;
404 404
405 405 return 1;
406 406 }
407 407
408 408 static bool is_points_to_user_data_fn(struct expression *expr)
409 409 {
410 410 int i;
411 411
412 412 expr = strip_expr(expr);
413 413 if (expr->type != EXPR_CALL || expr->fn->type != EXPR_SYMBOL ||
414 414 !expr->fn->symbol)
415 415 return false;
416 416 expr = expr->fn;
417 417 for (i = 0; i < ARRAY_SIZE(returns_pointer_to_user_data); i++) {
418 418 if (sym_name_is(returns_pointer_to_user_data[i], expr))
419 419 return true;
420 420 }
421 421 return false;
422 422 }
423 423
424 424 static int get_rl_from_function(struct expression *expr, struct range_list **rl)
425 425 {
426 426 int i;
427 427
428 428 if (expr->type != EXPR_CALL || expr->fn->type != EXPR_SYMBOL ||
429 429 !expr->fn->symbol_name || !expr->fn->symbol_name->name)
430 430 return 0;
431 431
432 432 for (i = 0; i < ARRAY_SIZE(returns_user_data); i++) {
433 433 if (strcmp(expr->fn->symbol_name->name, returns_user_data[i]) == 0) {
434 434 *rl = alloc_whole_rl(get_type(expr));
435 435 return 1;
436 436 }
437 437 }
438 438 return 0;
439 439 }
440 440
441 441 int points_to_user_data(struct expression *expr)
442 442 {
443 443 struct smatch_state *state;
444 444 struct range_list *rl;
445 445 char buf[256];
446 446 struct symbol *sym;
447 447 char *name;
448 448 int ret = 0;
449 449
450 450 expr = strip_expr(expr);
451 451 if (!expr)
452 452 return 0;
453 453 if (is_skb_data(expr))
454 454 return 1;
455 455 if (is_points_to_user_data_fn(expr))
456 456 return 1;
457 457 if (get_rl_from_function(expr, &rl))
458 458 return 1;
459 459
460 460 if (expr->type == EXPR_BINOP && expr->op == '+') {
461 461 if (points_to_user_data(expr->left))
462 462 return 1;
463 463 if (points_to_user_data(expr->right))
464 464 return 1;
465 465 return 0;
466 466 }
467 467
468 468 name = expr_to_var_sym(expr, &sym);
469 469 if (!name || !sym)
470 470 goto free;
471 471 snprintf(buf, sizeof(buf), "*%s", name);
472 472 state = __get_state(my_id, buf, sym);
473 473 if (state && estate_rl(state))
474 474 ret = 1;
475 475 free:
476 476 free_string(name);
477 477 return ret;
478 478 }
479 479
480 480 static void set_points_to_user_data(struct expression *expr)
481 481 {
482 482 char *name;
483 483 struct symbol *sym;
484 484 char buf[256];
485 485 struct symbol *type;
486 486
487 487 name = expr_to_var_sym(expr, &sym);
488 488 if (!name || !sym)
489 489 goto free;
490 490 snprintf(buf, sizeof(buf), "*%s", name);
491 491 type = get_type(expr);
492 492 if (type && type->type == SYM_PTR)
493 493 type = get_real_base_type(type);
494 494 if (!type || type->type != SYM_BASETYPE)
495 495 type = &llong_ctype;
496 496 set_state(my_id, buf, sym, alloc_estate_whole(type));
497 497 free:
498 498 free_string(name);
499 499 }
500 500
501 501 static int comes_from_skb_data(struct expression *expr)
502 502 {
503 503 expr = strip_expr(expr);
504 504 if (!expr || expr->type != EXPR_PREOP || expr->op != '*')
505 505 return 0;
506 506
507 507 expr = strip_expr(expr->unop);
508 508 if (!expr)
509 509 return 0;
510 510 if (expr->type == EXPR_BINOP && expr->op == '+')
511 511 expr = strip_expr(expr->left);
512 512
513 513 return is_skb_data(expr);
514 514 }
515 515
516 516 static int handle_struct_assignment(struct expression *expr)
517 517 {
518 518 struct expression *right;
519 519 struct symbol *left_type, *right_type;
520 520
521 521 left_type = get_type(expr->left);
522 522 if (!left_type || left_type->type != SYM_PTR)
523 523 return 0;
524 524 left_type = get_real_base_type(left_type);
525 525 if (!left_type)
526 526 return 0;
527 527 if (left_type->type != SYM_STRUCT &&
528 528 left_type->type != SYM_UNION)
529 529 return 0;
530 530
531 531 /*
532 532 * Ignore struct to struct assignments because for those we look at the
533 533 * individual members.
534 534 */
535 535 right = strip_expr(expr->right);
536 536 right_type = get_type(right);
537 537 if (!right_type || right_type->type != SYM_PTR)
538 538 return 0;
539 539
540 540 /* If we are assigning struct members then normally that is handled
541 541 * by fake assignments, however if we cast one struct to a different
542 542 * of struct then we handle that here.
543 543 */
544 544 right_type = get_real_base_type(right_type);
545 545 if (right_type == left_type)
546 546 return 0;
547 547
548 548 if (!points_to_user_data(right))
549 549 return 0;
550 550
551 551 tag_as_user_data(expr->left);
552 552 return 1;
553 553 }
554 554
555 555 static int handle_get_user(struct expression *expr)
556 556 {
557 557 char *name;
558 558 int ret = 0;
559 559
560 560 name = get_macro_name(expr->pos);
561 561 if (!name || strcmp(name, "get_user") != 0)
562 562 return 0;
563 563
564 564 name = expr_to_var(expr->right);
565 565 if (!name || (strcmp(name, "__val_gu") != 0 && strcmp(name, "__gu_val") != 0))
566 566 goto free;
567 567 set_state_expr(my_id, expr->left, alloc_estate_whole(get_type(expr->left)));
568 568 ret = 1;
569 569 free:
570 570 free_string(name);
571 571 return ret;
572 572 }
573 573
574 574 static bool handle_op_assign(struct expression *expr)
575 575 {
576 576 struct expression *binop_expr;
577 577 struct smatch_state *state;
578 578 struct range_list *rl;
579 579
580 580 switch (expr->op) {
581 581 case SPECIAL_ADD_ASSIGN:
582 582 case SPECIAL_SUB_ASSIGN:
583 583 case SPECIAL_AND_ASSIGN:
584 584 case SPECIAL_MOD_ASSIGN:
585 585 case SPECIAL_SHL_ASSIGN:
586 586 case SPECIAL_SHR_ASSIGN:
587 587 case SPECIAL_OR_ASSIGN:
588 588 case SPECIAL_XOR_ASSIGN:
589 589 case SPECIAL_MUL_ASSIGN:
590 590 case SPECIAL_DIV_ASSIGN:
591 591 binop_expr = binop_expression(expr->left,
592 592 op_remove_assign(expr->op),
593 593 expr->right);
594 594 if (!get_user_rl(binop_expr, &rl))
595 595 return true;
596 596
597 597 rl = cast_rl(get_type(expr->left), rl);
598 598 state = alloc_estate_rl(rl);
599 599 if (user_rl_capped(binop_expr))
600 600 estate_set_capped(state);
601 601 if (user_rl_treat_untagged(expr->left))
602 602 estate_set_treat_untagged(state);
603 603 set_state_expr(my_id, expr->left, state);
604 604 return true;
605 605 }
606 606 return false;
607 607 }
608 608
609 609 static void match_assign(struct expression *expr)
610 610 {
611 611 struct range_list *rl;
612 612 static struct expression *handled;
613 613 struct smatch_state *state;
614 614 struct expression *faked;
615 615
616 616 faked = get_faked_expression();
617 617 if (faked && faked == handled)
618 618 return;
619 619 if (is_fake_call(expr->right))
620 620 goto clear_old_state;
621 621 if (handle_get_user(expr))
622 622 return;
623 623 if (points_to_user_data(expr->right)) {
624 624 handled = expr;
625 625 set_points_to_user_data(expr->left);
626 626 }
627 627 if (handle_struct_assignment(expr))
628 628 return;
629 629
630 630 if (handle_op_assign(expr))
631 631 return;
632 632 if (expr->op != '=')
633 633 goto clear_old_state;
634 634
635 635 /* Handled by DB code */
636 636 if (expr->right->type == EXPR_CALL || __in_fake_parameter_assign)
637 637 return;
638 638
639 639 if (!get_user_rl(expr->right, &rl))
640 640 goto clear_old_state;
641 641
642 642 rl = cast_rl(get_type(expr->left), rl);
643 643 state = alloc_estate_rl(rl);
644 644
645 645 if (user_rl_capped(expr->right))
646 646 estate_set_capped(state);
647 647 if (user_rl_treat_untagged(expr->right))
648 648 estate_set_treat_untagged(state);
649 649 set_state_expr(my_id, expr->left, state);
650 650
651 651 return;
652 652
653 653 clear_old_state:
654 654 if (get_state_expr(my_id, expr->left))
655 655 set_state_expr(my_id, expr->left, alloc_estate_empty());
656 656 }
657 657
658 658 static void handle_eq_noteq(struct expression *expr)
659 659 {
660 660 struct smatch_state *left_orig, *right_orig;
661 661
662 662 left_orig = get_state_expr(my_id, expr->left);
663 663 right_orig = get_state_expr(my_id, expr->right);
664 664
665 665 if (!left_orig && !right_orig)
666 666 return;
667 667 if (left_orig && right_orig)
668 668 return;
669 669
670 670 if (left_orig) {
671 671 set_true_false_states_expr(my_id, expr->left,
672 672 expr->op == SPECIAL_EQUAL ? alloc_estate_empty() : NULL,
673 673 expr->op == SPECIAL_EQUAL ? NULL : alloc_estate_empty());
674 674 } else {
675 675 set_true_false_states_expr(my_id, expr->right,
676 676 expr->op == SPECIAL_EQUAL ? alloc_estate_empty() : NULL,
677 677 expr->op == SPECIAL_EQUAL ? NULL : alloc_estate_empty());
678 678 }
679 679 }
680 680
681 681 static struct range_list *strip_negatives(struct range_list *rl)
682 682 {
683 683 sval_t min = rl_min(rl);
684 684 sval_t minus_one;
685 685 sval_t over;
686 686 sval_t max = sval_type_max(rl_type(rl));
687 687
688 688 minus_one.type = rl_type(rl);
689 689 minus_one.value = -1;
690 690 over.type = rl_type(rl);
691 691 over.value = INT_MAX + 1ULL;
692 692
693 693 if (!rl)
694 694 return NULL;
695 695
696 696 if (type_unsigned(rl_type(rl)) && type_bits(rl_type(rl)) > 31)
697 697 return remove_range(rl, over, max);
698 698
699 699 return remove_range(rl, min, minus_one);
700 700 }
701 701
702 702 static void handle_compare(struct expression *expr)
703 703 {
704 704 struct expression *left, *right;
705 705 struct range_list *left_rl = NULL;
706 706 struct range_list *right_rl = NULL;
707 707 struct range_list *user_rl;
708 708 struct smatch_state *capped_state;
709 709 struct smatch_state *left_true = NULL;
710 710 struct smatch_state *left_false = NULL;
711 711 struct smatch_state *right_true = NULL;
712 712 struct smatch_state *right_false = NULL;
713 713 struct symbol *type;
714 714 sval_t sval;
715 715
716 716 left = strip_expr(expr->left);
717 717 right = strip_expr(expr->right);
718 718
719 719 while (left->type == EXPR_ASSIGNMENT)
720 720 left = strip_expr(left->left);
721 721
722 722 /*
723 723 * Conditions are mostly handled by smatch_extra.c, but there are some
724 724 * times where the exact values are not known so we can't do that.
725 725 *
726 726 * Normally, we might consider using smatch_capped.c to supliment smatch
727 727 * extra but that doesn't work when we merge unknown uncapped kernel
728 728 * data with unknown capped user data. The result is uncapped user
729 729 * data. We need to keep it separate and say that the user data is
730 730 * capped. In the past, I would have marked this as just regular
731 731 * kernel data (not user data) but we can't do that these days because
732 732 * we need to track user data for Spectre.
733 733 *
734 734 * The other situation which we have to handle is when we do have an
735 735 * int and we compare against an unknown unsigned kernel variable. In
736 736 * that situation we assume that the kernel data is less than INT_MAX.
737 737 * Otherwise then we get all sorts of array underflow false positives.
738 738 *
739 739 */
740 740
741 741 /* Handled in smatch_extra.c */
742 742 if (get_implied_value(left, &sval) ||
743 743 get_implied_value(right, &sval))
744 744 return;
745 745
746 746 get_user_rl(left, &left_rl);
747 747 get_user_rl(right, &right_rl);
748 748
749 749 /* nothing to do */
750 750 if (!left_rl && !right_rl)
751 751 return;
752 752 /* if both sides are user data that's not a good limit */
753 753 if (left_rl && right_rl)
754 754 return;
755 755
756 756 if (left_rl)
757 757 user_rl = left_rl;
758 758 else
759 759 user_rl = right_rl;
760 760
761 761 type = get_type(expr);
762 762 if (type_unsigned(type))
763 763 user_rl = strip_negatives(user_rl);
764 764 capped_state = alloc_estate_rl(user_rl);
765 765 estate_set_capped(capped_state);
766 766
767 767 switch (expr->op) {
768 768 case '<':
769 769 case SPECIAL_UNSIGNED_LT:
770 770 case SPECIAL_LTE:
771 771 case SPECIAL_UNSIGNED_LTE:
772 772 if (left_rl)
773 773 left_true = capped_state;
774 774 else
775 775 right_false = capped_state;
776 776 break;
777 777 case '>':
778 778 case SPECIAL_UNSIGNED_GT:
779 779 case SPECIAL_GTE:
780 780 case SPECIAL_UNSIGNED_GTE:
781 781 if (left_rl)
782 782 left_false = capped_state;
783 783 else
784 784 right_true = capped_state;
785 785 break;
786 786 }
787 787
788 788 set_true_false_states_expr(my_id, left, left_true, left_false);
789 789 set_true_false_states_expr(my_id, right, right_true, right_false);
790 790 }
791 791
792 792 static void match_condition(struct expression *expr)
793 793 {
794 794 if (expr->type != EXPR_COMPARE)
795 795 return;
796 796
797 797 if (expr->op == SPECIAL_EQUAL ||
798 798 expr->op == SPECIAL_NOTEQUAL) {
799 799 handle_eq_noteq(expr);
800 800 return;
801 801 }
802 802
803 803 handle_compare(expr);
804 804 }
805 805
806 806 static void match_user_assign_function(const char *fn, struct expression *expr, void *unused)
807 807 {
808 808 tag_as_user_data(expr->left);
809 809 set_points_to_user_data(expr->left);
810 810 }
811 811
812 812 static void match_returns_user_rl(const char *fn, struct expression *expr, void *unused)
813 813 {
814 814 func_gets_user_data = true;
815 815 }
816 816
817 817 static int get_user_macro_rl(struct expression *expr, struct range_list **rl)
818 818 {
819 819 struct expression *parent;
820 820 char *macro;
821 821
822 822 if (!expr)
823 823 return 0;
824 824
825 825 macro = get_macro_name(expr->pos);
826 826 if (!macro)
827 827 return 0;
828 828
829 829 /* handle ntohl(foo[i]) where "i" is trusted */
830 830 parent = expr_get_parent_expr(expr);
831 831 while (parent && parent->type != EXPR_BINOP)
832 832 parent = expr_get_parent_expr(parent);
833 833 if (parent && parent->type == EXPR_BINOP) {
834 834 char *parent_macro = get_macro_name(parent->pos);
835 835
836 836 if (parent_macro && strcmp(macro, parent_macro) == 0)
837 837 return 0;
838 838 }
839 839
840 840 if (strcmp(macro, "ntohl") == 0) {
841 841 *rl = alloc_whole_rl(&uint_ctype);
842 842 return 1;
843 843 }
844 844 if (strcmp(macro, "ntohs") == 0) {
845 845 *rl = alloc_whole_rl(&ushort_ctype);
846 846 return 1;
847 847 }
848 848 return 0;
849 849 }
850 850
851 851 static int has_user_data(struct symbol *sym)
852 852 {
853 853 struct sm_state *tmp;
854 854
855 855 FOR_EACH_MY_SM(my_id, __get_cur_stree(), tmp) {
856 856 if (tmp->sym == sym)
857 857 return 1;
858 858 } END_FOR_EACH_SM(tmp);
859 859 return 0;
860 860 }
861 861
862 862 static int we_pass_user_data(struct expression *call)
863 863 {
864 864 struct expression *arg;
865 865 struct symbol *sym;
866 866
867 867 FOR_EACH_PTR(call->args, arg) {
868 868 sym = expr_to_sym(arg);
869 869 if (!sym)
870 870 continue;
871 871 if (has_user_data(sym))
872 872 return 1;
873 873 } END_FOR_EACH_PTR(arg);
874 874
875 875 return 0;
876 876 }
877 877
878 878 static int db_returned_user_rl(struct expression *call, struct range_list **rl)
879 879 {
880 880 struct smatch_state *state;
881 881 char buf[48];
882 882
883 883 if (is_fake_call(call))
884 884 return 0;
885 885 snprintf(buf, sizeof(buf), "return %p", call);
886 886 state = get_state(my_id, buf, NULL);
887 887 if (!state || !estate_rl(state))
888 888 return 0;
889 889 *rl = estate_rl(state);
890 890 return 1;
891 891 }
892 892
893 893 struct stree *get_user_stree(void)
894 894 {
895 895 return get_all_states_stree(my_id);
896 896 }
897 897
898 898 static int user_data_flag;
899 899 static int no_user_data_flag;
900 900 struct range_list *var_user_rl(struct expression *expr)
901 901 {
902 902 struct smatch_state *state;
903 903 struct range_list *rl;
904 904 struct range_list *absolute_rl;
905 905
906 906 if (expr->type == EXPR_PREOP && expr->op == '&') {
907 907 no_user_data_flag = 1;
908 908 return NULL;
909 909 }
910 910
911 911 if (expr->type == EXPR_BINOP && expr->op == '%') {
912 912 struct range_list *left, *right;
913 913
914 914 if (!get_user_rl(expr->right, &right))
915 915 return NULL;
916 916 get_absolute_rl(expr->left, &left);
917 917 rl = rl_binop(left, '%', right);
918 918 goto found;
919 919 }
920 920
921 921 if (expr->type == EXPR_BINOP && expr->op == '/') {
922 922 struct range_list *left = NULL;
923 923 struct range_list *right = NULL;
924 924 struct range_list *abs_right;
925 925
926 926 /*
927 927 * The specific bug I'm dealing with is:
928 928 *
929 929 * foo = capped_user / unknown;
930 930 *
931 931 * Instead of just saying foo is now entirely user_rl we should
932 932 * probably say instead that it is not at all user data.
933 933 *
934 934 */
935 935
936 936 get_user_rl(expr->left, &left);
937 937 get_user_rl(expr->right, &right);
938 938 get_absolute_rl(expr->right, &abs_right);
939 939
940 940 if (left && !right) {
941 941 rl = rl_binop(left, '/', abs_right);
942 942 if (sval_cmp(rl_max(left), rl_max(rl)) < 0)
943 943 no_user_data_flag = 1;
944 944 }
945 945
946 946 return NULL;
947 947 }
948 948
949 949 if (get_rl_from_function(expr, &rl))
950 950 goto found;
951 951
952 952 if (get_user_macro_rl(expr, &rl))
953 953 goto found;
954 954
955 955 if (comes_from_skb_data(expr)) {
956 956 rl = alloc_whole_rl(get_type(expr));
957 957 goto found;
958 958 }
959 959
960 960 state = get_state_expr(my_id, expr);
961 961 if (state && estate_rl(state)) {
962 962 rl = estate_rl(state);
963 963 goto found;
964 964 }
965 965
966 966 if (expr->type == EXPR_CALL && db_returned_user_rl(expr, &rl))
967 967 goto found;
968 968
969 969 if (is_array(expr)) {
970 970 struct expression *array = get_array_base(expr);
971 971
972 972 if (!get_state_expr(my_id, array)) {
973 973 no_user_data_flag = 1;
974 974 return NULL;
975 975 }
976 976 }
977 977
978 978 if (expr->type == EXPR_PREOP && expr->op == '*' &&
979 979 is_user_rl(expr->unop)) {
980 980 rl = var_to_absolute_rl(expr);
981 981 goto found;
982 982 }
983 983
984 984 return NULL;
985 985 found:
986 986 user_data_flag = 1;
987 987 absolute_rl = var_to_absolute_rl(expr);
988 988 return clone_rl(rl_intersection(rl, absolute_rl));
989 989 }
990 990
991 991 static bool is_ptr_subtract(struct expression *expr)
992 992 {
993 993 expr = strip_expr(expr);
994 994 if (!expr)
995 995 return false;
996 996 if (expr->type == EXPR_BINOP && expr->op == '-' &&
997 997 type_is_ptr(get_type(expr->left))) {
998 998 return true;
999 999 }
1000 1000 return false;
1001 1001 }
1002 1002
1003 1003 int get_user_rl(struct expression *expr, struct range_list **rl)
1004 1004 {
1005 1005 if (is_ptr_subtract(expr))
1006 1006 return 0;
1007 1007
1008 1008 user_data_flag = 0;
1009 1009 no_user_data_flag = 0;
1010 1010 custom_get_absolute_rl(expr, &var_user_rl, rl);
1011 1011 if (!user_data_flag || no_user_data_flag)
1012 1012 *rl = NULL;
1013 1013
1014 1014 return !!*rl;
1015 1015 }
1016 1016
1017 1017 int is_user_rl(struct expression *expr)
1018 1018 {
1019 1019 struct range_list *tmp;
1020 1020
1021 1021 return !!get_user_rl(expr, &tmp);
1022 1022 }
1023 1023
1024 1024 int get_user_rl_var_sym(const char *name, struct symbol *sym, struct range_list **rl)
1025 1025 {
1026 1026 struct smatch_state *state;
1027 1027
1028 1028 state = get_state(my_id, name, sym);
1029 1029 if (state && estate_rl(state)) {
1030 1030 *rl = estate_rl(state);
1031 1031 return 1;
1032 1032 }
1033 1033 return 0;
1034 1034 }
1035 1035
1036 1036 static char *get_user_rl_str(struct expression *expr, struct symbol *type)
1037 1037 {
1038 1038 struct range_list *rl;
1039 1039 static char buf[64];
1040 1040
1041 1041 if (!get_user_rl(expr, &rl))
1042 1042 return NULL;
1043 1043 rl = cast_rl(type, rl);
1044 1044 snprintf(buf, sizeof(buf), "%s%s%s",
1045 1045 show_rl(rl),
1046 1046 user_rl_capped(expr) ? "[c]" : "",
1047 1047 user_rl_treat_untagged(expr) ? "[u]" : "");
1048 1048 return buf;
1049 1049 }
1050 1050
1051 1051 static void match_call_info(struct expression *expr)
1052 1052 {
1053 1053 struct expression *arg;
1054 1054 struct symbol *type;
1055 1055 char *str;
1056 1056 int i;
1057 1057
1058 1058 i = -1;
1059 1059 FOR_EACH_PTR(expr->args, arg) {
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1060 1060 i++;
1061 1061 type = get_arg_type(expr->fn, i);
1062 1062 str = get_user_rl_str(arg, type);
1063 1063 if (!str)
1064 1064 continue;
1065 1065
1066 1066 sql_insert_caller_info(expr, USER_DATA, i, "$", str);
1067 1067 } END_FOR_EACH_PTR(arg);
1068 1068 }
1069 1069
1070 -static int is_struct_ptr(struct symbol *sym)
1071 -{
1072 - struct symbol *type;
1073 -
1074 - if (!sym)
1075 - return 0;
1076 - type = get_real_base_type(sym);
1077 - if (!type || type->type != SYM_PTR)
1078 - return 0;
1079 - type = get_real_base_type(type);
1080 - if (!type || type->type != SYM_STRUCT)
1081 - return 0;
1082 - return 1;
1083 -}
1084 -
1085 1070 static void struct_member_callback(struct expression *call, int param, char *printed_name, struct sm_state *sm)
1086 1071 {
1087 1072 struct smatch_state *state;
1088 1073 struct range_list *rl;
1089 1074 struct symbol *type;
1090 1075 char buf[64];
1091 1076
1092 1077 /*
1093 1078 * Smatch uses a hack where if we get an unsigned long we say it's
1094 1079 * both user data and it points to user data. But if we pass it to a
1095 1080 * function which takes an int, then it's just user data. There's not
1096 1081 * enough bytes for it to be a pointer.
1097 1082 *
1098 1083 */
1099 1084 type = get_arg_type(call->fn, param);
1100 1085 if (type && type_bits(type) < type_bits(&ptr_ctype))
1101 1086 return;
1102 1087
1103 1088 if (strcmp(sm->state->name, "") == 0)
1104 1089 return;
1105 1090
1106 1091 if (strcmp(printed_name, "*$") == 0 &&
1107 1092 is_struct_ptr(sm->sym))
1108 1093 return;
1109 1094
1110 1095 state = __get_state(SMATCH_EXTRA, sm->name, sm->sym);
1111 1096 if (!state || !estate_rl(state))
1112 1097 rl = estate_rl(sm->state);
1113 1098 else
1114 1099 rl = rl_intersection(estate_rl(sm->state), estate_rl(state));
1115 1100
1116 1101 if (!rl)
1117 1102 return;
1118 1103
1119 1104 snprintf(buf, sizeof(buf), "%s%s%s", show_rl(rl),
1120 1105 estate_capped(sm->state) ? "[c]" : "",
1121 1106 estate_treat_untagged(sm->state) ? "[u]" : "");
1122 1107 sql_insert_caller_info(call, USER_DATA, param, printed_name, buf);
1123 1108 }
1124 1109
1125 1110 static void db_param_set(struct expression *expr, int param, char *key, char *value)
1126 1111 {
1127 1112 struct expression *arg;
1128 1113 char *name;
1129 1114 struct symbol *sym;
1130 1115 struct smatch_state *state;
1131 1116
1132 1117 while (expr->type == EXPR_ASSIGNMENT)
1133 1118 expr = strip_expr(expr->right);
1134 1119 if (expr->type != EXPR_CALL)
1135 1120 return;
1136 1121
1137 1122 arg = get_argument_from_call_expr(expr->args, param);
1138 1123 if (!arg)
1139 1124 return;
1140 1125 name = get_variable_from_key(arg, key, &sym);
1141 1126 if (!name || !sym)
1142 1127 goto free;
1143 1128
1144 1129 state = get_state(my_id, name, sym);
1145 1130 if (!state)
1146 1131 goto free;
1147 1132
1148 1133 set_state(my_id, name, sym, alloc_estate_empty());
1149 1134 free:
1150 1135 free_string(name);
1151 1136 }
1152 1137
1153 1138 static bool param_data_capped(const char *value)
1154 1139 {
1155 1140 if (strstr(value, ",c") || strstr(value, "[c"))
1156 1141 return true;
1157 1142 return false;
1158 1143 }
1159 1144
1160 1145 static bool param_data_treat_untagged(const char *value)
1161 1146 {
1162 1147 if (strstr(value, ",u") || strstr(value, "[u"))
1163 1148 return true;
1164 1149 return false;
1165 1150 }
1166 1151
1167 1152 static void set_param_user_data(const char *name, struct symbol *sym, char *key, char *value)
1168 1153 {
1169 1154 struct range_list *rl = NULL;
1170 1155 struct smatch_state *state;
1171 1156 struct expression *expr;
1172 1157 struct symbol *type;
1173 1158 char fullname[256];
1174 1159 char *key_orig = key;
1175 1160 bool add_star = false;
1176 1161
1177 1162 if (strcmp(key, "**$") == 0) {
1178 1163 snprintf(fullname, sizeof(fullname), "**%s", name);
1179 1164 } else {
1180 1165 if (key[0] == '*') {
1181 1166 add_star = true;
1182 1167 key++;
1183 1168 }
1184 1169
1185 1170 snprintf(fullname, 256, "%s%s%s", add_star ? "*" : "", name, key + 1);
1186 1171 }
1187 1172
1188 1173 expr = symbol_expression(sym);
1189 1174 type = get_member_type_from_key(expr, key_orig);
1190 1175
1191 1176 /*
1192 1177 * Say this function takes a struct ponter but the caller passes
1193 1178 * this_function(skb->data). We have two options, we could pass *$
1194 1179 * as user data or we could pass foo->bar, foo->baz as user data.
1195 1180 * The second option is easier to implement so we do that.
1196 1181 *
1197 1182 */
1198 1183 if (strcmp(key_orig, "*$") == 0) {
1199 1184 struct symbol *tmp = type;
1200 1185
1201 1186 while (tmp && tmp->type == SYM_PTR)
1202 1187 tmp = get_real_base_type(tmp);
1203 1188
1204 1189 if (tmp && (tmp->type == SYM_STRUCT || tmp->type == SYM_UNION)) {
1205 1190 tag_as_user_data(symbol_expression(sym));
1206 1191 return;
1207 1192 }
1208 1193 }
1209 1194
1210 1195 str_to_rl(type, value, &rl);
1211 1196 state = alloc_estate_rl(rl);
1212 1197 if (param_data_capped(value) || is_capped(expr))
1213 1198 estate_set_capped(state);
1214 1199 if (param_data_treat_untagged(value) || sym->ctype.as == 5)
1215 1200 estate_set_treat_untagged(state);
1216 1201 set_state(my_id, fullname, sym, state);
1217 1202 }
1218 1203
1219 1204 static void set_called(const char *name, struct symbol *sym, char *key, char *value)
1220 1205 {
1221 1206 set_state(my_call_id, "this_function", NULL, &called);
1222 1207 }
1223 1208
1224 1209 static void match_syscall_definition(struct symbol *sym)
1225 1210 {
1226 1211 struct symbol *arg;
1227 1212 char *macro;
1228 1213 char *name;
1229 1214 int is_syscall = 0;
1230 1215
1231 1216 macro = get_macro_name(sym->pos);
1232 1217 if (macro &&
1233 1218 (strncmp("SYSCALL_DEFINE", macro, strlen("SYSCALL_DEFINE")) == 0 ||
1234 1219 strncmp("COMPAT_SYSCALL_DEFINE", macro, strlen("COMPAT_SYSCALL_DEFINE")) == 0))
1235 1220 is_syscall = 1;
1236 1221
1237 1222 name = get_function();
1238 1223 if (!option_no_db && get_state(my_call_id, "this_function", NULL) != &called) {
1239 1224 if (name && strncmp(name, "sys_", 4) == 0)
1240 1225 is_syscall = 1;
1241 1226 }
1242 1227
1243 1228 if (name && strncmp(name, "compat_sys_", 11) == 0)
1244 1229 is_syscall = 1;
1245 1230
1246 1231 if (!is_syscall)
1247 1232 return;
1248 1233
1249 1234 FOR_EACH_PTR(sym->ctype.base_type->arguments, arg) {
1250 1235 set_state(my_id, arg->ident->name, arg, alloc_estate_whole(get_real_base_type(arg)));
1251 1236 } END_FOR_EACH_PTR(arg);
1252 1237 }
1253 1238
1254 1239 static void store_user_data_return(struct expression *expr, char *key, char *value)
1255 1240 {
1256 1241 struct range_list *rl;
1257 1242 struct symbol *type;
1258 1243 char buf[48];
1259 1244
1260 1245 if (strcmp(key, "$") != 0)
1261 1246 return;
1262 1247
1263 1248 type = get_type(expr);
1264 1249 snprintf(buf, sizeof(buf), "return %p", expr);
1265 1250 call_results_to_rl(expr, type, value, &rl);
1266 1251
1267 1252 set_state(my_id, buf, NULL, alloc_estate_rl(rl));
1268 1253 }
1269 1254
1270 1255 static void set_to_user_data(struct expression *expr, char *key, char *value)
1271 1256 {
1272 1257 struct smatch_state *state;
1273 1258 char *name;
1274 1259 struct symbol *sym;
1275 1260 struct symbol *type;
1276 1261 struct range_list *rl = NULL;
1277 1262
1278 1263 type = get_member_type_from_key(expr, key);
1279 1264 name = get_variable_from_key(expr, key, &sym);
1280 1265 if (!name || !sym)
1281 1266 goto free;
1282 1267
1283 1268 call_results_to_rl(expr, type, value, &rl);
1284 1269
1285 1270 state = alloc_estate_rl(rl);
1286 1271 if (param_data_capped(value))
1287 1272 estate_set_capped(state);
1288 1273 if (param_data_treat_untagged(value))
1289 1274 estate_set_treat_untagged(state);
1290 1275 set_state(my_id, name, sym, state);
1291 1276 free:
1292 1277 free_string(name);
1293 1278 }
1294 1279
1295 1280 static void returns_param_user_data(struct expression *expr, int param, char *key, char *value)
1296 1281 {
1297 1282 struct expression *arg;
1298 1283 struct expression *call;
1299 1284
1300 1285 call = expr;
1301 1286 while (call->type == EXPR_ASSIGNMENT)
1302 1287 call = strip_expr(call->right);
1303 1288 if (call->type != EXPR_CALL)
1304 1289 return;
1305 1290
1306 1291 if (!we_pass_user_data(call))
1307 1292 return;
1308 1293
1309 1294 if (param == -1) {
1310 1295 if (expr->type != EXPR_ASSIGNMENT) {
1311 1296 store_user_data_return(expr, key, value);
1312 1297 return;
1313 1298 }
1314 1299 set_to_user_data(expr->left, key, value);
1315 1300 return;
1316 1301 }
1317 1302
1318 1303 arg = get_argument_from_call_expr(call->args, param);
1319 1304 if (!arg)
1320 1305 return;
1321 1306 set_to_user_data(arg, key, value);
1322 1307 }
1323 1308
1324 1309 static void returns_param_user_data_set(struct expression *expr, int param, char *key, char *value)
1325 1310 {
1326 1311 struct expression *arg;
1327 1312
1328 1313 func_gets_user_data = true;
1329 1314
1330 1315 if (param == -1) {
1331 1316 if (expr->type != EXPR_ASSIGNMENT) {
1332 1317 store_user_data_return(expr, key, value);
1333 1318 return;
1334 1319 }
1335 1320 if (strcmp(key, "*$") == 0) {
1336 1321 set_points_to_user_data(expr->left);
1337 1322 tag_as_user_data(expr->left);
1338 1323 } else {
1339 1324 set_to_user_data(expr->left, key, value);
1340 1325 }
1341 1326 return;
1342 1327 }
1343 1328
1344 1329 while (expr->type == EXPR_ASSIGNMENT)
1345 1330 expr = strip_expr(expr->right);
1346 1331 if (expr->type != EXPR_CALL)
1347 1332 return;
1348 1333
1349 1334 arg = get_argument_from_call_expr(expr->args, param);
1350 1335 if (!arg)
1351 1336 return;
1352 1337 set_to_user_data(arg, key, value);
1353 1338 }
1354 1339
1355 1340 static void param_set_to_user_data(int return_id, char *return_ranges, struct expression *expr)
1356 1341 {
1357 1342 struct sm_state *sm;
1358 1343 struct smatch_state *start_state;
1359 1344 struct range_list *rl;
1360 1345 int param;
1361 1346 char *return_str;
1362 1347 const char *param_name;
1363 1348 struct symbol *ret_sym;
1364 1349 bool return_found = false;
1365 1350 bool pointed_at_found = false;
1366 1351 char buf[64];
1367 1352
1368 1353 expr = strip_expr(expr);
1369 1354 return_str = expr_to_str(expr);
1370 1355 ret_sym = expr_to_sym(expr);
1371 1356
1372 1357 FOR_EACH_MY_SM(my_id, __get_cur_stree(), sm) {
1373 1358 param = get_param_num_from_sym(sm->sym);
1374 1359 if (param < 0)
1375 1360 continue;
1376 1361
1377 1362 if (!param_was_set_var_sym(sm->name, sm->sym))
1378 1363 continue;
1379 1364
1380 1365 /* The logic here was that if we were passed in a user data then
1381 1366 * we don't record that. It's like the difference between
1382 1367 * param_filter and param_set. When I think about it, I'm not
1383 1368 * sure it actually works. It's probably harmless because we
1384 1369 * checked earlier that we're not returning a parameter...
1385 1370 * Let's mark this as a TODO.
1386 1371 */
1387 1372 start_state = get_state_stree(start_states, my_id, sm->name, sm->sym);
1388 1373 if (start_state && rl_equiv(estate_rl(sm->state), estate_rl(start_state)))
1389 1374 continue;
1390 1375
1391 1376 param_name = get_param_name(sm);
1392 1377 if (!param_name)
1393 1378 continue;
1394 1379 if (strcmp(param_name, "$") == 0) /* The -1 param is handled after the loop */
1395 1380 continue;
1396 1381
1397 1382 snprintf(buf, sizeof(buf), "%s%s%s",
1398 1383 show_rl(estate_rl(sm->state)),
1399 1384 estate_capped(sm->state) ? "[c]" : "",
1400 1385 estate_treat_untagged(sm->state) ? "[u]" : "");
1401 1386 sql_insert_return_states(return_id, return_ranges,
1402 1387 func_gets_user_data ? USER_DATA_SET : USER_DATA,
1403 1388 param, param_name, buf);
1404 1389 } END_FOR_EACH_SM(sm);
1405 1390
1406 1391 /* This if for "return foo;" where "foo->bar" is user data. */
1407 1392 FOR_EACH_MY_SM(my_id, __get_cur_stree(), sm) {
1408 1393 if (!ret_sym)
1409 1394 break;
1410 1395 if (ret_sym != sm->sym)
1411 1396 continue;
1412 1397
1413 1398 param_name = state_name_to_param_name(sm->name, return_str);
1414 1399 if (!param_name)
1415 1400 continue;
1416 1401 if (strcmp(param_name, "$") == 0)
1417 1402 return_found = true;
1418 1403 if (strcmp(param_name, "*$") == 0)
1419 1404 pointed_at_found = true;
1420 1405 snprintf(buf, sizeof(buf), "%s%s%s",
1421 1406 show_rl(estate_rl(sm->state)),
1422 1407 estate_capped(sm->state) ? "[c]" : "",
1423 1408 estate_treat_untagged(sm->state) ? "[u]" : "");
1424 1409 sql_insert_return_states(return_id, return_ranges,
1425 1410 func_gets_user_data ? USER_DATA_SET : USER_DATA,
1426 1411 -1, param_name, buf);
1427 1412 } END_FOR_EACH_SM(sm);
1428 1413
1429 1414 /* This if for "return ntohl(foo);" */
1430 1415 if (!return_found && get_user_rl(expr, &rl)) {
1431 1416 snprintf(buf, sizeof(buf), "%s%s%s",
1432 1417 show_rl(rl),
1433 1418 user_rl_capped(expr) ? "[c]" : "",
1434 1419 user_rl_treat_untagged(expr) ? "[u]" : "");
1435 1420 sql_insert_return_states(return_id, return_ranges,
1436 1421 func_gets_user_data ? USER_DATA_SET : USER_DATA,
1437 1422 -1, "$", buf);
1438 1423 }
1439 1424
1440 1425 /*
1441 1426 * This is to handle things like return skb->data where we don't set a
1442 1427 * state for that.
1443 1428 */
1444 1429 if (!pointed_at_found && points_to_user_data(expr)) {
1445 1430 sql_insert_return_states(return_id, return_ranges,
1446 1431 (is_skb_data(expr) || func_gets_user_data) ?
1447 1432 USER_DATA_SET : USER_DATA,
1448 1433 -1, "*$", "s64min-s64max");
1449 1434 }
1450 1435
1451 1436 free_string(return_str);
1452 1437 }
1453 1438
1454 1439 static void returns_param_capped(struct expression *expr, int param, char *key, char *value)
1455 1440 {
1456 1441 struct smatch_state *state, *new;
1457 1442 struct symbol *sym;
1458 1443 char *name;
1459 1444
1460 1445 name = return_state_to_var_sym(expr, param, key, &sym);
1461 1446 if (!name || !sym)
1462 1447 goto free;
1463 1448
1464 1449 state = get_state(my_id, name, sym);
1465 1450 if (!state || estate_capped(state))
1466 1451 goto free;
1467 1452
1468 1453 new = clone_estate(state);
1469 1454 estate_set_capped(new);
1470 1455
1471 1456 set_state(my_id, name, sym, new);
1472 1457 free:
1473 1458 free_string(name);
1474 1459 }
1475 1460
1476 1461 static struct int_stack *gets_data_stack;
1477 1462 static void match_function_def(struct symbol *sym)
1478 1463 {
1479 1464 func_gets_user_data = false;
1480 1465 }
1481 1466
1482 1467 static void match_inline_start(struct expression *expr)
1483 1468 {
1484 1469 push_int(&gets_data_stack, func_gets_user_data);
1485 1470 }
1486 1471
1487 1472 static void match_inline_end(struct expression *expr)
1488 1473 {
1489 1474 func_gets_user_data = pop_int(&gets_data_stack);
1490 1475 }
1491 1476
1492 1477 void register_kernel_user_data(int id)
1493 1478 {
1494 1479 int i;
1495 1480
1496 1481 my_id = id;
1497 1482
1498 1483 if (option_project != PROJ_KERNEL)
1499 1484 return;
1500 1485
1501 1486 set_dynamic_states(my_id);
1502 1487
1503 1488 add_hook(&match_function_def, FUNC_DEF_HOOK);
1504 1489 add_hook(&match_inline_start, INLINE_FN_START);
1505 1490 add_hook(&match_inline_end, INLINE_FN_END);
1506 1491
1507 1492 add_hook(&save_start_states, AFTER_DEF_HOOK);
1508 1493 add_hook(&free_start_states, AFTER_FUNC_HOOK);
1509 1494 add_hook(&match_save_states, INLINE_FN_START);
1510 1495 add_hook(&match_restore_states, INLINE_FN_END);
1511 1496
1512 1497 add_unmatched_state_hook(my_id, &empty_state);
1513 1498 add_extra_nomod_hook(&extra_nomod_hook);
1514 1499 add_pre_merge_hook(my_id, &pre_merge_hook);
1515 1500 add_merge_hook(my_id, &merge_estates);
1516 1501
1517 1502 add_function_hook("copy_from_user", &match_user_copy, INT_PTR(0));
1518 1503 add_function_hook("__copy_from_user", &match_user_copy, INT_PTR(0));
1519 1504 add_function_hook("memcpy_fromiovec", &match_user_copy, INT_PTR(0));
1520 1505 for (i = 0; i < ARRAY_SIZE(kstr_funcs); i++)
1521 1506 add_function_hook(kstr_funcs[i], &match_user_copy, INT_PTR(2));
1522 1507 add_function_hook("usb_control_msg", &match_user_copy, INT_PTR(6));
1523 1508
1524 1509 for (i = 0; i < ARRAY_SIZE(returns_user_data); i++) {
1525 1510 add_function_assign_hook(returns_user_data[i], &match_user_assign_function, NULL);
1526 1511 add_function_hook(returns_user_data[i], &match_returns_user_rl, NULL);
1527 1512 }
1528 1513
1529 1514 add_function_hook("sscanf", &match_sscanf, NULL);
1530 1515
1531 1516 add_hook(&match_syscall_definition, AFTER_DEF_HOOK);
1532 1517
1533 1518 add_hook(&match_assign, ASSIGNMENT_HOOK);
1534 1519 select_return_states_hook(PARAM_SET, &db_param_set);
1535 1520 add_hook(&match_condition, CONDITION_HOOK);
1536 1521
1537 1522 add_hook(&match_call_info, FUNCTION_CALL_HOOK);
1538 1523 add_member_info_callback(my_id, struct_member_callback);
1539 1524 select_caller_info_hook(set_param_user_data, USER_DATA);
1540 1525 select_return_states_hook(USER_DATA, &returns_param_user_data);
1541 1526 select_return_states_hook(USER_DATA_SET, &returns_param_user_data_set);
1542 1527 select_return_states_hook(CAPPED_DATA, &returns_param_capped);
1543 1528 add_split_return_callback(¶m_set_to_user_data);
1544 1529 }
1545 1530
1546 1531 void register_kernel_user_data2(int id)
1547 1532 {
1548 1533 my_call_id = id;
1549 1534
1550 1535 if (option_project != PROJ_KERNEL)
1551 1536 return;
1552 1537 select_caller_info_hook(set_called, INTERNAL);
1553 1538 }
1554 1539
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