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mtag/math: use mtag information
[smatch.git] / check_user_data2.c
blob8d5516aa0e2631ade6f5ffe7d1a496455c9d4bd7
1 /*
2 * Copyright (C) 2011 Dan Carpenter.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License
6 * as published by the Free Software Foundation; either version 2
7 * of the License, or (at your option) any later version.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, see http://www.gnu.org/copyleft/gpl.txt
16 */
17
18 /*
19 * There are a couple checks that try to see if a variable
20 * comes from the user. It would be better to unify them
21 * into one place. Also it we should follow the data down
22 * the call paths. Hence this file.
23 */
24
25 #include "smatch.h"
26 #include "smatch_slist.h"
27 #include "smatch_extra.h"
28
29 static int my_id;
30 static int my_call_id;
31
32 STATE(called);
33 static bool func_gets_user_data;
34
35 static const char * kstr_funcs[] = {
36 "kstrtoull", "kstrtoll", "kstrtoul", "kstrtol", "kstrtouint",
37 "kstrtoint", "kstrtou64", "kstrtos64", "kstrtou32", "kstrtos32",
38 "kstrtou16", "kstrtos16", "kstrtou8", "kstrtos8", "kstrtoull_from_user"
39 "kstrtoll_from_user", "kstrtoul_from_user", "kstrtol_from_user",
40 "kstrtouint_from_user", "kstrtoint_from_user", "kstrtou16_from_user",
41 "kstrtos16_from_user", "kstrtou8_from_user", "kstrtos8_from_user",
42 "kstrtou64_from_user", "kstrtos64_from_user", "kstrtou32_from_user",
43 "kstrtos32_from_user",
44 };
45
46 static void set_points_to_user_data(struct expression *expr);
47
48 static struct stree *start_states;
49 static struct stree_stack *saved_stack;
50 static void save_start_states(struct statement *stmt)
51 {
52 start_states = clone_stree(__get_cur_stree());
53 }
54
55 static void free_start_states(void)
56 {
57 free_stree(&start_states);
58 }
59
60 static void match_save_states(struct expression *expr)
61 {
62 push_stree(&saved_stack, start_states);
63 start_states = NULL;
64 }
65
66 static void match_restore_states(struct expression *expr)
67 {
68 free_stree(&start_states);
69 start_states = pop_stree(&saved_stack);
70 }
71
72 static struct smatch_state *empty_state(struct sm_state *sm)
73 {
74 return alloc_estate_empty();
75 }
76
77 static void pre_merge_hook(struct sm_state *sm)
78 {
79 struct smatch_state *user;
80 struct smatch_state *extra;
81 struct range_list *rl;
82 sval_t dummy;
83 sval_t sval_100 = {
84 .type = &int_ctype,
85 .value = 100,
86 };
87
88 user = get_state(my_id, sm->name, sm->sym);
89 if (!user)
90 return;
91 if (!__in_function_def && !estate_rl(sm->state)) {
92 /*
93 * If the one side is capped and the other side is empty then
94 * let's just mark it as not-user data because the information
95 * isn't going to be useful. How this looks is:
96 *
97 * if (user_var > trusted)
98 * user_var = trusted; <-- empty state
99 * else
100 * <-- capped
101 *
102 * The problem is that sometimes things are capped to a literal
103 * and we'd like to keep the state in that case... Ugh. I've
104 * added a check which assumes that everything less than 100 is
105 * probably capped against a literal.
106 *
107 */
108 if (is_capped_var_sym(sm->name, sm->sym) &&
109 sval_cmp(estate_max(user), sval_100) > 0)
110 set_state(my_id, sm->name, sm->sym, alloc_estate_empty());
111 return;
112 }
113 extra = get_state(SMATCH_EXTRA, sm->name, sm->sym);
114 if (!extra || !estate_rl(extra))
115 return;
116 rl = rl_intersection(estate_rl(user), estate_rl(extra));
117 if (rl_to_sval(rl, &dummy))
118 rl = NULL;
119 set_state(my_id, sm->name, sm->sym, alloc_estate_rl(clone_rl(rl)));
120 }
121
122 static void extra_nomod_hook(const char *name, struct symbol *sym, struct expression *expr, struct smatch_state *state)
123 {
124 struct smatch_state *user;
125 struct range_list *rl;
126
127 user = get_state(my_id, name, sym);
128 if (!user)
129 return;
130 rl = rl_intersection(estate_rl(user), estate_rl(state));
131 if (rl_equiv(rl, estate_rl(user)))
132 return;
133 set_state(my_id, name, sym, alloc_estate_rl(rl));
134 }
135
136 static void tag_inner_struct_members(struct expression *expr, struct symbol *member)
137 {
138 struct expression *edge_member;
139 struct symbol *base = get_real_base_type(member);
140 struct symbol *tmp;
141
142 if (member->ident)
143 expr = member_expression(expr, '.', member->ident);
144
145 FOR_EACH_PTR(base->symbol_list, tmp) {
146 struct symbol *type;
147
148 type = get_real_base_type(tmp);
149 if (!type)
150 continue;
151
152 if (type->type == SYM_UNION || type->type == SYM_STRUCT) {
153 tag_inner_struct_members(expr, tmp);
154 continue;
155 }
156
157 if (!tmp->ident)
158 continue;
159
160 edge_member = member_expression(expr, '.', tmp->ident);
161 set_state_expr(my_id, edge_member, alloc_estate_whole(type));
162 } END_FOR_EACH_PTR(tmp);
163 }
164
165 static void tag_struct_members(struct symbol *type, struct expression *expr)
166 {
167 struct symbol *tmp;
168 struct expression *member;
169 int op = '*';
170
171 if (expr->type == EXPR_PREOP && expr->op == '&') {
172 expr = strip_expr(expr->unop);
173 op = '.';
174 }
175
176 FOR_EACH_PTR(type->symbol_list, tmp) {
177 type = get_real_base_type(tmp);
178 if (!type)
179 continue;
180
181 if (type->type == SYM_UNION || type->type == SYM_STRUCT) {
182 tag_inner_struct_members(expr, tmp);
183 continue;
184 }
185
186 if (!tmp->ident)
187 continue;
188
189 member = member_expression(expr, op, tmp->ident);
190 set_state_expr(my_id, member, alloc_estate_whole(get_type(member)));
191
192 if (type->type == SYM_ARRAY)
193 set_points_to_user_data(member);
194 } END_FOR_EACH_PTR(tmp);
195 }
196
197 static void tag_base_type(struct expression *expr)
198 {
199 if (expr->type == EXPR_PREOP && expr->op == '&')
200 expr = strip_expr(expr->unop);
201 else
202 expr = deref_expression(expr);
203 set_state_expr(my_id, expr, alloc_estate_whole(get_type(expr)));
204 }
205
206 static void tag_as_user_data(struct expression *expr)
207 {
208 struct symbol *type;
209
210 expr = strip_expr(expr);
211
212 type = get_type(expr);
213 if (!type || type->type != SYM_PTR)
214 return;
215 type = get_real_base_type(type);
216 if (!type)
217 return;
218 if (type == &void_ctype) {
219 set_state_expr(my_id, deref_expression(expr), alloc_estate_whole(&ulong_ctype));
220 return;
221 }
222 if (type->type == SYM_BASETYPE)
223 tag_base_type(expr);
224 if (type->type == SYM_STRUCT || type->type == SYM_UNION) {
225 if (expr->type != EXPR_PREOP || expr->op != '&')
226 expr = deref_expression(expr);
227 else
228 set_state_expr(my_id, deref_expression(expr), alloc_estate_whole(&ulong_ctype));
229 tag_struct_members(type, expr);
230 }
231 }
232
233 static void match_user_copy(const char *fn, struct expression *expr, void *_param)
234 {
235 int param = PTR_INT(_param);
236 struct expression *dest;
237
238 func_gets_user_data = true;
239
240 dest = get_argument_from_call_expr(expr->args, param);
241 dest = strip_expr(dest);
242 if (!dest)
243 return;
244 tag_as_user_data(dest);
245 }
246
247 static int is_dev_attr_name(struct expression *expr)
248 {
249 char *name;
250 int ret = 0;
251
252 name = expr_to_str(expr);
253 if (!name)
254 return 0;
255 if (strstr(name, "->attr.name"))
256 ret = 1;
257 free_string(name);
258 return ret;
259 }
260
261 static int ends_in_n(struct expression *expr)
262 {
263 struct string *str;
264
265 if (!expr)
266 return 0;
267 if (expr->type != EXPR_STRING || !expr->string)
268 return 0;
269
270 str = expr->string;
271 if (str->length < 3)
272 return 0;
273
274 if (str->data[str->length - 3] == '%' &&
275 str->data[str->length - 2] == 'n')
276 return 1;
277 return 0;
278 }
279
280 static void match_sscanf(const char *fn, struct expression *expr, void *unused)
281 {
282 struct expression *str, *format, *arg;
283 int i, last;
284
285 func_gets_user_data = true;
286
287 str = get_argument_from_call_expr(expr->args, 0);
288 if (is_dev_attr_name(str))
289 return;
290
291 format = get_argument_from_call_expr(expr->args, 1);
292 if (is_dev_attr_name(format))
293 return;
294
295 last = ptr_list_size((struct ptr_list *)expr->args) - 1;
296
297 i = -1;
298 FOR_EACH_PTR(expr->args, arg) {
299 i++;
300 if (i < 2)
301 continue;
302 if (i == last && ends_in_n(format))
303 continue;
304 tag_as_user_data(arg);
305 } END_FOR_EACH_PTR(arg);
306 }
307
308 static int is_skb_data(struct expression *expr)
309 {
310 struct symbol *sym;
311
312 if (!expr)
313 return 0;
314
315 if (expr->type == EXPR_BINOP && expr->op == '+')
316 return is_skb_data(expr->left);
317
318 expr = strip_expr(expr);
319 if (!expr)
320 return 0;
321 if (expr->type != EXPR_DEREF || expr->op != '.')
322 return 0;
323
324 if (!expr->member)
325 return 0;
326 if (strcmp(expr->member->name, "data") != 0)
327 return 0;
328
329 sym = expr_to_sym(expr->deref);
330 if (!sym)
331 return 0;
332 sym = get_real_base_type(sym);
333 if (!sym || sym->type != SYM_PTR)
334 return 0;
335 sym = get_real_base_type(sym);
336 if (!sym || sym->type != SYM_STRUCT || !sym->ident)
337 return 0;
338 if (strcmp(sym->ident->name, "sk_buff") != 0)
339 return 0;
340
341 return 1;
342 }
343
344 static int points_to_user_data(struct expression *expr)
345 {
346 struct smatch_state *state;
347 char buf[256];
348 struct symbol *sym;
349 char *name;
350 int ret = 0;
351
352 expr = strip_expr(expr);
353 if (!expr)
354 return 0;
355 if (is_skb_data(expr))
356 return 1;
357
358 if (expr->type == EXPR_BINOP && expr->op == '+') {
359 if (points_to_user_data(expr->left))
360 return 1;
361 if (points_to_user_data(expr->right))
362 return 1;
363 return 0;
364 }
365
366 name = expr_to_var_sym(expr, &sym);
367 if (!name || !sym)
368 goto free;
369 snprintf(buf, sizeof(buf), "*%s", name);
370 state = get_state(my_id, buf, sym);
371 if (state && estate_rl(state))
372 ret = 1;
373 free:
374 free_string(name);
375 return ret;
376 }
377
378 static void set_points_to_user_data(struct expression *expr)
379 {
380 char *name;
381 struct symbol *sym;
382 char buf[256];
383
384 name = expr_to_var_sym(expr, &sym);
385 if (!name || !sym)
386 goto free;
387 snprintf(buf, sizeof(buf), "*%s", name);
388 set_state(my_id, buf, sym, alloc_estate_whole(&llong_ctype));
389 free:
390 free_string(name);
391 }
392
393 static int comes_from_skb_data(struct expression *expr)
394 {
395 expr = strip_expr(expr);
396 if (!expr || expr->type != EXPR_PREOP || expr->op != '*')
397 return 0;
398
399 expr = strip_expr(expr->unop);
400 if (!expr)
401 return 0;
402 if (expr->type == EXPR_BINOP && expr->op == '+')
403 expr = strip_expr(expr->left);
404
405 return is_skb_data(expr);
406 }
407
408 static int handle_struct_assignment(struct expression *expr)
409 {
410 struct expression *right;
411 struct symbol *left_type, *right_type;
412
413 left_type = get_type(expr->left);
414 if (!left_type || left_type->type != SYM_PTR)
415 return 0;
416 left_type = get_real_base_type(left_type);
417 if (!left_type)
418 return 0;
419 if (left_type->type != SYM_STRUCT &&
420 left_type->type != SYM_UNION)
421 return 0;
422
423 /*
424 * Ignore struct to struct assignments because for those we look at the
425 * individual members.
426 */
427 right = strip_expr(expr->right);
428 right_type = get_type(right);
429 if (!right_type || right_type->type != SYM_PTR)
430 return 0;
431
432 /* If we are assigning struct members then normally that is handled
433 * by fake assignments, however if we cast one struct to a different
434 * of struct then we handle that here.
435 */
436 right_type = get_real_base_type(right_type);
437 if (right_type == left_type)
438 return 0;
439
440 if (!points_to_user_data(right))
441 return 0;
442
443 tag_as_user_data(expr->left);
444 return 1;
445 }
446
447 static int handle_get_user(struct expression *expr)
448 {
449 char *name;
450 int ret = 0;
451
452 name = get_macro_name(expr->pos);
453 if (!name || strcmp(name, "get_user") != 0)
454 return 0;
455
456 name = expr_to_var(expr->right);
457 if (!name || strcmp(name, "__val_gu") != 0)
458 goto free;
459 set_state_expr(my_id, expr->left, alloc_estate_whole(get_type(expr->left)));
460 ret = 1;
461 free:
462 free_string(name);
463 return ret;
464 }
465
466 static void match_assign(struct expression *expr)
467 {
468 struct range_list *rl;
469
470 if (is_fake_call(expr->right))
471 return;
472 if (handle_get_user(expr))
473 return;
474 if (points_to_user_data(expr->right))
475 set_points_to_user_data(expr->left);
476 if (handle_struct_assignment(expr))
477 return;
478
479 if (!get_user_rl(expr->right, &rl))
480 goto clear_old_state;
481
482 rl = cast_rl(get_type(expr->left), rl);
483 set_state_expr(my_id, expr->left, alloc_estate_rl(rl));
484
485 return;
486
487 clear_old_state:
488 if (get_state_expr(my_id, expr->left))
489 set_state_expr(my_id, expr->left, alloc_estate_empty());
490 }
491
492 static void handle_eq_noteq(struct expression *expr)
493 {
494 struct smatch_state *left_orig, *right_orig;
495
496 left_orig = get_state_expr(my_id, expr->left);
497 right_orig = get_state_expr(my_id, expr->right);
498
499 if (!left_orig && !right_orig)
500 return;
501 if (left_orig && right_orig)
502 return;
503
504 if (left_orig) {
505 set_true_false_states_expr(my_id, expr->left,
506 expr->op == SPECIAL_EQUAL ? alloc_estate_empty() : NULL,
507 expr->op == SPECIAL_EQUAL ? NULL : alloc_estate_empty());
508 } else {
509 set_true_false_states_expr(my_id, expr->right,
510 expr->op == SPECIAL_EQUAL ? alloc_estate_empty() : NULL,
511 expr->op == SPECIAL_EQUAL ? NULL : alloc_estate_empty());
512 }
513 }
514
515 static void handle_unsigned_lt_gt(struct expression *expr)
516 {
517 struct symbol *type;
518 struct range_list *left;
519 struct range_list *right;
520 struct range_list *non_negative;
521 sval_t min, minus_one;
522
523 /*
524 * conditions are mostly handled by smatch_extra.c. The special case
525 * here is that say you have if (user_int < unknown_u32) {
526 * In Smatch extra we say that, We have no idea what value
527 * unknown_u32 is so the only thin we can say for sure is that
528 * user_int is not -1 (UINT_MAX). But in check_user_data2.c we should
529 * assume that unless unknown_u32 is user data, it's probably less than
530 * INT_MAX.
531 *
532 */
533
534 type = get_type(expr);
535 if (!type_unsigned(type))
536 return;
537
538 /*
539 * Assume if (user < trusted) { ... because I am lazy and because this
540 * is the correct way to write code.
541 */
542 if (!get_user_rl(expr->left, &left))
543 return;
544 if (get_user_rl(expr->right, &right))
545 return;
546
547 if (!sval_is_negative(rl_min(left)))
548 return;
549 min = rl_min(left);
550 minus_one.type = rl_type(left);
551 minus_one.value = -1;
552 non_negative = remove_range(left, min, minus_one);
553
554 switch (expr->op) {
555 case '<':
556 case SPECIAL_UNSIGNED_LT:
557 case SPECIAL_LTE:
558 case SPECIAL_UNSIGNED_LTE:
559 set_true_false_states_expr(my_id, expr->left,
560 alloc_estate_rl(non_negative), NULL);
561 break;
562 case '>':
563 case SPECIAL_UNSIGNED_GT:
564 case SPECIAL_GTE:
565 case SPECIAL_UNSIGNED_GTE:
566 set_true_false_states_expr(my_id, expr->left,
567 NULL, alloc_estate_rl(non_negative));
568 break;
569 }
570 }
571
572 static void match_condition(struct expression *expr)
573 {
574 if (expr->type != EXPR_COMPARE)
575 return;
576
577 if (expr->op == SPECIAL_EQUAL ||
578 expr->op == SPECIAL_NOTEQUAL) {
579 handle_eq_noteq(expr);
580 return;
581 }
582
583 handle_unsigned_lt_gt(expr);
584 }
585
586 static void match_user_assign_function(const char *fn, struct expression *expr, void *unused)
587 {
588 func_gets_user_data = true;
589
590 tag_as_user_data(expr->left);
591 set_points_to_user_data(expr->left);
592 }
593
594 static void match_returns_user_rl(const char *fn, struct expression *expr, void *unused)
595 {
596 struct smatch_state *estate;
597 struct range_list *rl;
598
599 func_gets_user_data = true;
600
601 rl = alloc_whole_rl(get_type(expr->right));
602 rl = cast_rl(get_type(expr->left), rl);
603 estate = alloc_estate_rl(rl);
604 set_state_expr(my_id, expr->left, estate);
605 }
606
607 static int get_user_macro_rl(struct expression *expr, struct range_list **rl)
608 {
609 struct expression *parent;
610 char *macro;
611
612 if (!expr)
613 return 0;
614
615 macro = get_macro_name(expr->pos);
616 if (!macro)
617 return 0;
618
619 /* handle ntohl(foo[i]) where "i" is trusted */
620 parent = expr_get_parent_expr(expr);
621 while (parent && parent->type != EXPR_BINOP)
622 parent = expr_get_parent_expr(parent);
623 if (parent && parent->type == EXPR_BINOP) {
624 char *parent_macro = get_macro_name(parent->pos);
625
626 if (parent_macro && strcmp(macro, parent_macro) == 0)
627 return 0;
628 }
629
630 if (strcmp(macro, "ntohl") == 0) {
631 *rl = alloc_whole_rl(&uint_ctype);
632 return 1;
633 }
634 if (strcmp(macro, "ntohs") == 0) {
635 *rl = alloc_whole_rl(&ushort_ctype);
636 return 1;
637 }
638 return 0;
639 }
640
641 struct db_info {
642 struct range_list *rl;
643 struct expression *call;
644 };
645 static int returned_rl_callback(void *_info, int argc, char **argv, char **azColName)
646 {
647 struct db_info *db_info = _info;
648 struct range_list *rl;
649 char *return_ranges = argv[0];
650 char *user_ranges = argv[1];
651 struct expression *arg;
652 int comparison;
653
654 if (argc != 2)
655 return 0;
656
657 call_results_to_rl(db_info->call, get_type(db_info->call), user_ranges, &rl);
658 if (str_to_comparison_arg(return_ranges, db_info->call, &comparison, &arg) &&
659 comparison == SPECIAL_EQUAL) {
660 struct range_list *orig_rl;
661
662 if (!get_user_rl(arg, &orig_rl))
663 return 0;
664 rl = rl_intersection(rl, orig_rl);
665 if (!rl)
666 return 0;
667 }
668 db_info->rl = rl_union(db_info->rl, rl);
669
670 return 0;
671 }
672
673 static int has_user_data(struct symbol *sym)
674 {
675 struct sm_state *tmp;
676
677 FOR_EACH_MY_SM(my_id, __get_cur_stree(), tmp) {
678 if (tmp->sym == sym)
679 return 1;
680 } END_FOR_EACH_SM(tmp);
681 return 0;
682 }
683
684 static int we_pass_user_data(struct expression *call)
685 {
686 struct expression *arg;
687 struct symbol *sym;
688
689 FOR_EACH_PTR(call->args, arg) {
690 sym = expr_to_sym(arg);
691 if (!sym)
692 continue;
693 if (has_user_data(sym))
694 return 1;
695 } END_FOR_EACH_PTR(arg);
696
697 return 0;
698 }
699
700 static int db_returned_user_rl(struct expression *call, struct range_list **rl)
701 {
702 struct db_info db_info = {};
703
704 /* for function pointers assume everything is used */
705 if (call->fn->type != EXPR_SYMBOL)
706 return 0;
707 if (is_fake_call(call))
708 return 0;
709
710 db_info.call = call;
711 run_sql(&returned_rl_callback, &db_info,
712 "select return, value from return_states where %s and type = %d and parameter = -1 and key = '$';",
713 get_static_filter(call->fn->symbol), USER_DATA3_SET);
714 if (db_info.rl) {
715 func_gets_user_data = true;
716 *rl = db_info.rl;
717 return 1;
718 }
719
720 run_sql(&returned_rl_callback, &db_info,
721 "select return, value from return_states where %s and type = %d and parameter = -1 and key = '$';",
722 get_static_filter(call->fn->symbol), USER_DATA3);
723 if (db_info.rl) {
724 if (!we_pass_user_data(call))
725 return 0;
726 *rl = db_info.rl;
727 return 1;
728 }
729
730 return 0;
731 }
732
733 static int user_data_flag;
734 static int no_user_data_flag;
735 static struct range_list *var_user_rl(struct expression *expr)
736 {
737 struct smatch_state *state;
738 struct range_list *rl;
739 struct range_list *absolute_rl;
740
741 if (expr->type == EXPR_BINOP && expr->op == '%') {
742 struct range_list *left, *right;
743
744 if (!get_user_rl(expr->right, &right))
745 return NULL;
746 get_absolute_rl(expr->left, &left);
747 rl = rl_binop(left, '%', right);
748 goto found;
749 }
750
751 if (!option_spammy && expr->type == EXPR_BINOP && expr->op == '/') {
752 struct range_list *left = NULL;
753 struct range_list *right = NULL;
754 struct range_list *abs_right;
755
756 /*
757 * The specific bug I'm dealing with is:
758 *
759 * foo = capped_user / unknown;
760 *
761 * Instead of just saying foo is now entirely user_rl we should
762 * probably say instead that it is not at all user data.
763 *
764 */
765
766 get_user_rl(expr->left, &left);
767 get_user_rl(expr->right, &right);
768 get_absolute_rl(expr->right, &abs_right);
769
770 if (left && !right) {
771 rl = rl_binop(left, '/', abs_right);
772 if (sval_cmp(rl_max(left), rl_max(rl)) < 0)
773 no_user_data_flag = 1;
774 }
775
776 return NULL;
777 }
778
779 if (get_user_macro_rl(expr, &rl))
780 goto found;
781
782 if (comes_from_skb_data(expr)) {
783 rl = alloc_whole_rl(get_type(expr));
784 goto found;
785 }
786
787 state = get_state_expr(my_id, expr);
788 if (state && estate_rl(state)) {
789 rl = estate_rl(state);
790 goto found;
791 }
792
793 if (expr->type == EXPR_CALL && db_returned_user_rl(expr, &rl))
794 goto found;
795
796 if (is_array(expr)) {
797 struct expression *array = get_array_base(expr);
798
799 if (!get_state_expr(my_id, array)) {
800 no_user_data_flag = 1;
801 return NULL;
802 }
803 }
804
805 return NULL;
806 found:
807 user_data_flag = 1;
808 absolute_rl = var_to_absolute_rl(expr);
809 return clone_rl(rl_intersection(rl, absolute_rl));
810 }
811
812 int get_user_rl(struct expression *expr, struct range_list **rl)
813 {
814 user_data_flag = 0;
815 no_user_data_flag = 0;
816 custom_get_absolute_rl(expr, &var_user_rl, rl);
817 if (!user_data_flag || no_user_data_flag)
818 *rl = NULL;
819
820 return !!*rl;
821 }
822
823 int get_user_rl_spammy(struct expression *expr, struct range_list **rl)
824 {
825 int ret;
826
827 option_spammy++;
828 ret = get_user_rl(expr, rl);
829 option_spammy--;
830
831 return ret;
832 }
833
834 int is_user_rl(struct expression *expr)
835 {
836 struct range_list *tmp;
837
838 return get_user_rl_spammy(expr, &tmp);
839 }
840
841 int get_user_rl_var_sym(const char *name, struct symbol *sym, struct range_list **rl)
842 {
843 struct smatch_state *state;
844
845 state = get_state(my_id, name, sym);
846 if (state && estate_rl(state)) {
847 *rl = estate_rl(state);
848 return 1;
849 }
850 return 0;
851 }
852
853 static void match_call_info(struct expression *expr)
854 {
855 struct range_list *rl;
856 struct expression *arg;
857 int i = 0;
858
859 i = -1;
860 FOR_EACH_PTR(expr->args, arg) {
861 i++;
862
863 if (!get_user_rl(arg, &rl))
864 continue;
865
866 sql_insert_caller_info(expr, USER_DATA3, i, "$", show_rl(rl));
867 } END_FOR_EACH_PTR(arg);
868 }
869
870 static int is_struct_ptr(struct symbol *sym)
871 {
872 struct symbol *type;
873
874 if (!sym)
875 return 0;
876 type = get_real_base_type(sym);
877 if (!type || type->type != SYM_PTR)
878 return 0;
879 type = get_real_base_type(type);
880 if (!type || type->type != SYM_STRUCT)
881 return 0;
882 return 1;
883 }
884
885 static void struct_member_callback(struct expression *call, int param, char *printed_name, struct sm_state *sm)
886 {
887 struct smatch_state *state;
888 struct range_list *rl;
889
890 if (strcmp(sm->state->name, "") == 0)
891 return;
892
893 if (strcmp(printed_name, "*$") == 0 &&
894 is_struct_ptr(sm->sym))
895 return;
896
897 state = get_state(SMATCH_EXTRA, sm->name, sm->sym);
898 if (!state || !estate_rl(state))
899 rl = estate_rl(sm->state);
900 else
901 rl = rl_intersection(estate_rl(sm->state), estate_rl(state));
902
903 sql_insert_caller_info(call, USER_DATA3, param, printed_name, show_rl(rl));
904 }
905
906 static void set_param_user_data(const char *name, struct symbol *sym, char *key, char *value)
907 {
908 struct range_list *rl = NULL;
909 struct smatch_state *state;
910 struct symbol *type;
911 char fullname[256];
912
913 if (strcmp(key, "*$") == 0)
914 snprintf(fullname, sizeof(fullname), "*%s", name);
915 else if (strncmp(key, "$", 1) == 0)
916 snprintf(fullname, 256, "%s%s", name, key + 1);
917 else
918 return;
919
920 type = get_member_type_from_key(symbol_expression(sym), key);
921
922 /* if the caller passes a void pointer with user data */
923 if (strcmp(key, "*$") == 0 && type && type != &void_ctype) {
924 struct expression *expr = symbol_expression(sym);
925
926 tag_as_user_data(expr);
927 set_points_to_user_data(expr);
928 return;
929 }
930 str_to_rl(type, value, &rl);
931 state = alloc_estate_rl(rl);
932 set_state(my_id, fullname, sym, state);
933 }
934
935 static void set_called(const char *name, struct symbol *sym, char *key, char *value)
936 {
937 set_state(my_call_id, "this_function", NULL, &called);
938 }
939
940 static void match_syscall_definition(struct symbol *sym)
941 {
942 struct symbol *arg;
943 char *macro;
944 char *name;
945 int is_syscall = 0;
946
947 macro = get_macro_name(sym->pos);
948 if (macro &&
949 (strncmp("SYSCALL_DEFINE", macro, strlen("SYSCALL_DEFINE")) == 0 ||
950 strncmp("COMPAT_SYSCALL_DEFINE", macro, strlen("COMPAT_SYSCALL_DEFINE")) == 0))
951 is_syscall = 1;
952
953 name = get_function();
954 if (!option_no_db && get_state(my_call_id, "this_function", NULL) != &called) {
955 if (name && strncmp(name, "sys_", 4) == 0)
956 is_syscall = 1;
957 }
958
959 if (name && strncmp(name, "compat_sys_", 11) == 0)
960 is_syscall = 1;
961
962 if (!is_syscall)
963 return;
964
965 FOR_EACH_PTR(sym->ctype.base_type->arguments, arg) {
966 set_state(my_id, arg->ident->name, arg, alloc_estate_whole(get_real_base_type(arg)));
967 } END_FOR_EACH_PTR(arg);
968 }
969
970 static void set_to_user_data(struct expression *expr, char *key, char *value)
971 {
972 char *name;
973 struct symbol *sym;
974 struct symbol *type;
975 struct range_list *rl = NULL;
976
977 type = get_member_type_from_key(expr, key);
978 name = get_variable_from_key(expr, key, &sym);
979 if (!name || !sym)
980 goto free;
981
982 call_results_to_rl(expr, type, value, &rl);
983
984 set_state(my_id, name, sym, alloc_estate_rl(rl));
985 free:
986 free_string(name);
987
988 }
989
990 static void returns_param_user_data(struct expression *expr, int param, char *key, char *value)
991 {
992 struct expression *arg;
993 struct expression *call;
994
995 call = expr;
996 while (call->type == EXPR_ASSIGNMENT)
997 call = strip_expr(call->right);
998 if (call->type != EXPR_CALL)
999 return;
1000
1001 if (!we_pass_user_data(call))
1002 return;
1003
1004 if (param == -1) {
1005 if (expr->type != EXPR_ASSIGNMENT)
1006 return;
1007 set_to_user_data(expr->left, key, value);
1008 return;
1009 }
1010
1011 arg = get_argument_from_call_expr(call->args, param);
1012 if (!arg)
1013 return;
1014 set_to_user_data(arg, key, value);
1015 }
1016
1017 static void returns_param_user_data_set(struct expression *expr, int param, char *key, char *value)
1018 {
1019 struct expression *arg;
1020
1021 func_gets_user_data = true;
1022
1023 if (param == -1) {
1024 if (expr->type != EXPR_ASSIGNMENT)
1025 return;
1026 if (strcmp(key, "*$") == 0) {
1027 set_points_to_user_data(expr->left);
1028 tag_as_user_data(expr->left);
1029 } else {
1030 set_to_user_data(expr->left, key, value);
1031 }
1032 return;
1033 }
1034
1035 while (expr->type == EXPR_ASSIGNMENT)
1036 expr = strip_expr(expr->right);
1037 if (expr->type != EXPR_CALL)
1038 return;
1039
1040 arg = get_argument_from_call_expr(expr->args, param);
1041 if (!arg)
1042 return;
1043 set_to_user_data(arg, key, value);
1044 }
1045
1046 static int has_empty_state(struct sm_state *sm)
1047 {
1048 struct sm_state *tmp;
1049
1050 FOR_EACH_PTR(sm->possible, tmp) {
1051 if (!estate_rl(tmp->state))
1052 return 1;
1053 } END_FOR_EACH_PTR(tmp);
1054
1055 return 0;
1056 }
1057
1058 static void param_set_to_user_data(int return_id, char *return_ranges, struct expression *expr)
1059 {
1060 struct sm_state *sm;
1061 struct smatch_state *start_state;
1062 struct range_list *rl;
1063 int param;
1064 char *return_str;
1065 const char *param_name;
1066
1067 expr = strip_expr(expr);
1068 return_str = expr_to_str(expr);
1069
1070 FOR_EACH_MY_SM(my_id, __get_cur_stree(), sm) {
1071 if (has_empty_state(sm))
1072 continue;
1073
1074 param = get_param_num_from_sym(sm->sym);
1075 if (param < 0) {
1076 if (expr_to_sym(expr) == sm->sym)
1077 param = -1;
1078 else
1079 continue;
1080 }
1081
1082 /* The logic here was that if we were passed in a user data then
1083 * we don't record that. It's like the difference between
1084 * param_filter and param_set. When I think about it, I'm not
1085 * sure it actually works. It's probably harmless because we
1086 * checked earlier that we're not returning a parameter...
1087 * Let's mark this as a TODO.
1088 */
1089 start_state = get_state_stree(start_states, my_id, sm->name, sm->sym);
1090 if (start_state && rl_equiv(estate_rl(sm->state), estate_rl(start_state)))
1091 continue;
1092
1093 if (param == -1)
1094 param_name = state_name_to_param_name(sm->name, return_str);
1095 else
1096 param_name = get_param_name(sm);
1097 if (!param_name)
1098 continue;
1099 if (strcmp(param_name, "$") == 0) /* The -1 param is handled after the loop */
1100 continue;
1101
1102 sql_insert_return_states(return_id, return_ranges,
1103 func_gets_user_data ? USER_DATA3_SET : USER_DATA3,
1104 param, param_name, show_rl(estate_rl(sm->state)));
1105 } END_FOR_EACH_SM(sm);
1106
1107 if (points_to_user_data(expr)) {
1108 sql_insert_return_states(return_id, return_ranges,
1109 (is_skb_data(expr) || !func_gets_user_data) ?
1110 USER_DATA3_SET : USER_DATA3,
1111 -1, "*$", "");
1112 } else if (get_user_rl(expr, &rl)) {
1113 sql_insert_return_states(return_id, return_ranges,
1114 func_gets_user_data ? USER_DATA3_SET : USER_DATA3,
1115 -1, "$", show_rl(rl));
1116 }
1117
1118 free_string(return_str);
1119 }
1120
1121 static struct int_stack *gets_data_stack;
1122 static void match_function_def(struct symbol *sym)
1123 {
1124 func_gets_user_data = false;
1125 }
1126
1127 static void match_inline_start(struct expression *expr)
1128 {
1129 push_int(&gets_data_stack, func_gets_user_data);
1130 }
1131
1132 static void match_inline_end(struct expression *expr)
1133 {
1134 func_gets_user_data = pop_int(&gets_data_stack);
1135 }
1136
1137 void check_user_data2(int id)
1138 {
1139 int i;
1140
1141 my_id = id;
1142
1143 if (option_project != PROJ_KERNEL)
1144 return;
1145
1146 add_hook(&match_function_def, FUNC_DEF_HOOK);
1147 add_hook(&match_inline_start, INLINE_FN_START);
1148 add_hook(&match_inline_end, INLINE_FN_END);
1149
1150 add_hook(&save_start_states, AFTER_DEF_HOOK);
1151 add_hook(&free_start_states, AFTER_FUNC_HOOK);
1152 add_hook(&match_save_states, INLINE_FN_START);
1153 add_hook(&match_restore_states, INLINE_FN_END);
1154
1155 add_unmatched_state_hook(my_id, &empty_state);
1156 add_extra_nomod_hook(&extra_nomod_hook);
1157 add_pre_merge_hook(my_id, &pre_merge_hook);
1158 add_merge_hook(my_id, &merge_estates);
1159
1160 add_function_hook("copy_from_user", &match_user_copy, INT_PTR(0));
1161 add_function_hook("__copy_from_user", &match_user_copy, INT_PTR(0));
1162 add_function_hook("memcpy_fromiovec", &match_user_copy, INT_PTR(0));
1163 for (i = 0; i < ARRAY_SIZE(kstr_funcs); i++)
1164 add_function_hook(kstr_funcs[i], &match_user_copy, INT_PTR(2));
1165
1166 add_function_assign_hook("simple_strtol", &match_returns_user_rl, NULL);
1167 add_function_assign_hook("simple_strtoll", &match_returns_user_rl, NULL);
1168 add_function_assign_hook("simple_strtoul", &match_returns_user_rl, NULL);
1169 add_function_assign_hook("simple_strtoull", &match_returns_user_rl, NULL);
1170 add_function_assign_hook("kvm_register_read", &match_returns_user_rl, NULL);
1171
1172 add_function_hook("sscanf", &match_sscanf, NULL);
1173
1174 add_function_assign_hook("memdup_user", &match_user_assign_function, NULL);
1175 add_function_assign_hook("kmap_atomic", &match_user_assign_function, NULL);
1176 add_function_assign_hook("skb_network_header", &match_user_assign_function, NULL);
1177
1178 add_hook(&match_syscall_definition, AFTER_DEF_HOOK);
1179
1180 add_hook(&match_assign, ASSIGNMENT_HOOK);
1181 add_hook(&match_condition, CONDITION_HOOK);
1182
1183 add_hook(&match_call_info, FUNCTION_CALL_HOOK);
1184 add_member_info_callback(my_id, struct_member_callback);
1185 select_caller_info_hook(set_param_user_data, USER_DATA3);
1186 select_return_states_hook(USER_DATA3, &returns_param_user_data);
1187 select_return_states_hook(USER_DATA3_SET, &returns_param_user_data_set);
1188 add_split_return_callback(&param_set_to_user_data);
1189 }
1190
1191 void check_user_data3(int id)
1192 {
1193 my_call_id = id;
1194
1195 if (option_project != PROJ_KERNEL)
1196 return;
1197 select_caller_info_hook(set_called, INTERNAL);
1198 }
1199
Static analysis for C