xref: /illumos-gate/usr/src/tools/smatch/src/smatch_kernel_user_data.c (revision 6523a3aa7f325d64841382707603be7a86e68147)
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 const char *returns_user_data[] = {
47 	"simple_strtol", "simple_strtoll", "simple_strtoul", "simple_strtoull",
48 	"kvm_register_read",
49 };
50 
51 static const char *returns_pointer_to_user_data[] = {
52 	"nlmsg_data", "nla_data", "memdup_user", "kmap_atomic", "skb_network_header",
53 };
54 
55 static void set_points_to_user_data(struct expression *expr);
56 
57 static struct stree *start_states;
58 static struct stree_stack *saved_stack;
save_start_states(struct statement * stmt)59 static void save_start_states(struct statement *stmt)
60 {
61 	start_states = clone_stree(__get_cur_stree());
62 }
63 
free_start_states(void)64 static void free_start_states(void)
65 {
66 	free_stree(&start_states);
67 }
68 
match_save_states(struct expression * expr)69 static void match_save_states(struct expression *expr)
70 {
71 	push_stree(&saved_stack, start_states);
72 	start_states = NULL;
73 }
74 
match_restore_states(struct expression * expr)75 static void match_restore_states(struct expression *expr)
76 {
77 	free_stree(&start_states);
78 	start_states = pop_stree(&saved_stack);
79 }
80 
empty_state(struct sm_state * sm)81 static struct smatch_state *empty_state(struct sm_state *sm)
82 {
83 	return alloc_estate_empty();
84 }
85 
pre_merge_hook(struct sm_state * cur,struct sm_state * other)86 static void pre_merge_hook(struct sm_state *cur, struct sm_state *other)
87 {
88 	struct smatch_state *user = cur->state;
89 	struct smatch_state *extra;
90 	struct smatch_state *state;
91 	struct range_list *rl;
92 
93 	extra = __get_state(SMATCH_EXTRA, cur->name, cur->sym);
94 	if (!extra)
95 		return;
96 	rl = rl_intersection(estate_rl(user), estate_rl(extra));
97 	state = alloc_estate_rl(clone_rl(rl));
98 	if (estate_capped(user) || is_capped_var_sym(cur->name, cur->sym))
99 		estate_set_capped(state);
100 	if (estate_treat_untagged(user))
101 		estate_set_treat_untagged(state);
102 	set_state(my_id, cur->name, cur->sym, state);
103 }
104 
extra_nomod_hook(const char * name,struct symbol * sym,struct expression * expr,struct smatch_state * state)105 static void extra_nomod_hook(const char *name, struct symbol *sym, struct expression *expr, struct smatch_state *state)
106 {
107 	struct smatch_state *user, *new;
108 	struct range_list *rl;
109 
110 	user = __get_state(my_id, name, sym);
111 	if (!user)
112 		return;
113 	rl = rl_intersection(estate_rl(user), estate_rl(state));
114 	if (rl_equiv(rl, estate_rl(user)))
115 		return;
116 	new = alloc_estate_rl(rl);
117 	if (estate_capped(user))
118 		estate_set_capped(new);
119 	if (estate_treat_untagged(user))
120 		estate_set_treat_untagged(new);
121 	set_state(my_id, name, sym, new);
122 }
123 
binop_capped(struct expression * expr)124 static bool binop_capped(struct expression *expr)
125 {
126 	struct range_list *left_rl;
127 	int comparison;
128 
129 	if (expr->op == '-' && get_user_rl(expr->left, &left_rl)) {
130 		if (user_rl_capped(expr->left))
131 			return true;
132 		comparison = get_comparison(expr->left, expr->right);
133 		if (comparison && show_special(comparison)[0] == '>')
134 			return true;
135 		return false;
136 	}
137 
138 	if (expr->op == '&' || expr->op == '%') {
139 		if (is_capped(expr->left) || is_capped(expr->right))
140 			return true;
141 		if (user_rl_capped(expr->left) || user_rl_capped(expr->right))
142 			return true;
143 		return false;
144 	}
145 
146 	if (user_rl_capped(expr->left) &&
147 	    user_rl_capped(expr->right))
148 		return true;
149 	return false;
150 }
151 
user_rl_capped(struct expression * expr)152 bool user_rl_capped(struct expression *expr)
153 {
154 	struct smatch_state *state;
155 	struct range_list *rl;
156 	sval_t sval;
157 
158 	expr = strip_expr(expr);
159 	if (!expr)
160 		return false;
161 	if (get_value(expr, &sval))
162 		return true;
163 	if (expr->type == EXPR_BINOP)
164 		return binop_capped(expr);
165 	if ((expr->type == EXPR_PREOP || expr->type == EXPR_POSTOP) &&
166 	    (expr->op == SPECIAL_INCREMENT || expr->op == SPECIAL_DECREMENT))
167 		return user_rl_capped(expr->unop);
168 	state = get_state_expr(my_id, expr);
169 	if (state)
170 		return estate_capped(state);
171 
172 	if (get_user_rl(expr, &rl))
173 		return false;  /* uncapped user data */
174 
175 	return true;  /* not actually user data */
176 }
177 
user_rl_treat_untagged(struct expression * expr)178 bool user_rl_treat_untagged(struct expression *expr)
179 {
180 	struct smatch_state *state;
181 	struct range_list *rl;
182 	sval_t sval;
183 
184 	expr = strip_expr(expr);
185 	if (!expr)
186 		return false;
187 	if (get_value(expr, &sval))
188 		return true;
189 
190 	state = get_state_expr(my_id, expr);
191 	if (state)
192 		return estate_treat_untagged(state);
193 
194 	if (get_user_rl(expr, &rl))
195 		return false;  /* uncapped user data */
196 
197 	return true;  /* not actually user data */
198 }
199 
tag_inner_struct_members(struct expression * expr,struct symbol * member)200 static void tag_inner_struct_members(struct expression *expr, struct symbol *member)
201 {
202 	struct expression *edge_member;
203 	struct symbol *base = get_real_base_type(member);
204 	struct symbol *tmp;
205 
206 	if (member->ident)
207 		expr = member_expression(expr, '.', member->ident);
208 
209 	FOR_EACH_PTR(base->symbol_list, tmp) {
210 		struct symbol *type;
211 
212 		type = get_real_base_type(tmp);
213 		if (!type)
214 			continue;
215 
216 		if (type->type == SYM_UNION || type->type == SYM_STRUCT) {
217 			tag_inner_struct_members(expr, tmp);
218 			continue;
219 		}
220 
221 		if (!tmp->ident)
222 			continue;
223 
224 		edge_member = member_expression(expr, '.', tmp->ident);
225 		set_state_expr(my_id, edge_member, alloc_estate_whole(type));
226 	} END_FOR_EACH_PTR(tmp);
227 }
228 
tag_struct_members(struct symbol * type,struct expression * expr)229 static void tag_struct_members(struct symbol *type, struct expression *expr)
230 {
231 	struct symbol *tmp;
232 	struct expression *member;
233 	int op = '*';
234 
235 	if (expr->type == EXPR_PREOP && expr->op == '&') {
236 		expr = strip_expr(expr->unop);
237 		op = '.';
238 	}
239 
240 	FOR_EACH_PTR(type->symbol_list, tmp) {
241 		type = get_real_base_type(tmp);
242 		if (!type)
243 			continue;
244 
245 		if (type->type == SYM_UNION || type->type == SYM_STRUCT) {
246 			tag_inner_struct_members(expr, tmp);
247 			continue;
248 		}
249 
250 		if (!tmp->ident)
251 			continue;
252 
253 		member = member_expression(expr, op, tmp->ident);
254 		set_state_expr(my_id, member, alloc_estate_whole(get_type(member)));
255 
256 		if (type->type == SYM_ARRAY)
257 			set_points_to_user_data(member);
258 	} END_FOR_EACH_PTR(tmp);
259 }
260 
tag_base_type(struct expression * expr)261 static void tag_base_type(struct expression *expr)
262 {
263 	if (expr->type == EXPR_PREOP && expr->op == '&')
264 		expr = strip_expr(expr->unop);
265 	else
266 		expr = deref_expression(expr);
267 	set_state_expr(my_id, expr, alloc_estate_whole(get_type(expr)));
268 }
269 
tag_as_user_data(struct expression * expr)270 static void tag_as_user_data(struct expression *expr)
271 {
272 	struct symbol *type;
273 
274 	expr = strip_expr(expr);
275 
276 	type = get_type(expr);
277 	if (!type || type->type != SYM_PTR)
278 		return;
279 	type = get_real_base_type(type);
280 	if (!type)
281 		return;
282 	if (type == &void_ctype) {
283 		set_state_expr(my_id, deref_expression(expr), alloc_estate_whole(&ulong_ctype));
284 		return;
285 	}
286 	if (type->type == SYM_BASETYPE)
287 		tag_base_type(expr);
288 	if (type->type == SYM_STRUCT || type->type == SYM_UNION) {
289 		if (expr->type != EXPR_PREOP || expr->op != '&')
290 			expr = deref_expression(expr);
291 		else
292 			set_state_expr(my_id, deref_expression(expr), alloc_estate_whole(&ulong_ctype));
293 		tag_struct_members(type, expr);
294 	}
295 }
296 
match_user_copy(const char * fn,struct expression * expr,void * _param)297 static void match_user_copy(const char *fn, struct expression *expr, void *_param)
298 {
299 	int param = PTR_INT(_param);
300 	struct expression *dest;
301 
302 	func_gets_user_data = true;
303 
304 	dest = get_argument_from_call_expr(expr->args, param);
305 	dest = strip_expr(dest);
306 	if (!dest)
307 		return;
308 	tag_as_user_data(dest);
309 }
310 
is_dev_attr_name(struct expression * expr)311 static int is_dev_attr_name(struct expression *expr)
312 {
313 	char *name;
314 	int ret = 0;
315 
316 	name = expr_to_str(expr);
317 	if (!name)
318 		return 0;
319 	if (strstr(name, "->attr.name"))
320 		ret = 1;
321 	free_string(name);
322 	return ret;
323 }
324 
ends_in_n(struct expression * expr)325 static int ends_in_n(struct expression *expr)
326 {
327 	struct string *str;
328 
329 	if (!expr)
330 		return 0;
331 	if (expr->type != EXPR_STRING || !expr->string)
332 		return 0;
333 
334 	str = expr->string;
335 	if (str->length < 3)
336 		return 0;
337 
338 	if (str->data[str->length - 3] == '%' &&
339 	    str->data[str->length - 2] == 'n')
340 		return 1;
341 	return 0;
342 }
343 
match_sscanf(const char * fn,struct expression * expr,void * unused)344 static void match_sscanf(const char *fn, struct expression *expr, void *unused)
345 {
346 	struct expression *str, *format, *arg;
347 	int i, last;
348 
349 	func_gets_user_data = true;
350 
351 	str = get_argument_from_call_expr(expr->args, 0);
352 	if (is_dev_attr_name(str))
353 		return;
354 
355 	format = get_argument_from_call_expr(expr->args, 1);
356 	if (is_dev_attr_name(format))
357 		return;
358 
359 	last = ptr_list_size((struct ptr_list *)expr->args) - 1;
360 
361 	i = -1;
362 	FOR_EACH_PTR(expr->args, arg) {
363 		i++;
364 		if (i < 2)
365 			continue;
366 		if (i == last && ends_in_n(format))
367 			continue;
368 		tag_as_user_data(arg);
369 	} END_FOR_EACH_PTR(arg);
370 }
371 
is_skb_data(struct expression * expr)372 static int is_skb_data(struct expression *expr)
373 {
374 	struct symbol *sym;
375 
376 	if (!expr)
377 		return 0;
378 
379 	if (expr->type == EXPR_BINOP && expr->op == '+')
380 		return is_skb_data(expr->left);
381 
382 	expr = strip_expr(expr);
383 	if (!expr)
384 		return 0;
385 	if (expr->type != EXPR_DEREF || expr->op != '.')
386 		return 0;
387 
388 	if (!expr->member)
389 		return 0;
390 	if (strcmp(expr->member->name, "data") != 0)
391 		return 0;
392 
393 	sym = expr_to_sym(expr->deref);
394 	if (!sym)
395 		return 0;
396 	sym = get_real_base_type(sym);
397 	if (!sym || sym->type != SYM_PTR)
398 		return 0;
399 	sym = get_real_base_type(sym);
400 	if (!sym || sym->type != SYM_STRUCT || !sym->ident)
401 		return 0;
402 	if (strcmp(sym->ident->name, "sk_buff") != 0)
403 		return 0;
404 
405 	return 1;
406 }
407 
is_points_to_user_data_fn(struct expression * expr)408 static bool is_points_to_user_data_fn(struct expression *expr)
409 {
410 	int i;
411 
412 	expr = strip_expr(expr);
413 	if (expr->type != EXPR_CALL || expr->fn->type != EXPR_SYMBOL ||
414 	    !expr->fn->symbol)
415 		return false;
416 	expr = expr->fn;
417 	for (i = 0; i < ARRAY_SIZE(returns_pointer_to_user_data); i++) {
418 		if (sym_name_is(returns_pointer_to_user_data[i], expr))
419 			return true;
420 	}
421 	return false;
422 }
423 
get_rl_from_function(struct expression * expr,struct range_list ** rl)424 static int get_rl_from_function(struct expression *expr, struct range_list **rl)
425 {
426 	int i;
427 
428 	if (expr->type != EXPR_CALL || expr->fn->type != EXPR_SYMBOL ||
429 	    !expr->fn->symbol_name || !expr->fn->symbol_name->name)
430 		return 0;
431 
432 	for (i = 0; i < ARRAY_SIZE(returns_user_data); i++) {
433 		if (strcmp(expr->fn->symbol_name->name, returns_user_data[i]) == 0) {
434 			*rl = alloc_whole_rl(get_type(expr));
435 			return 1;
436 		}
437 	}
438 	return 0;
439 }
440 
points_to_user_data(struct expression * expr)441 int points_to_user_data(struct expression *expr)
442 {
443 	struct smatch_state *state;
444 	struct range_list *rl;
445 	char buf[256];
446 	struct symbol *sym;
447 	char *name;
448 	int ret = 0;
449 
450 	expr = strip_expr(expr);
451 	if (!expr)
452 		return 0;
453 	if (is_skb_data(expr))
454 		return 1;
455 	if (is_points_to_user_data_fn(expr))
456 		return 1;
457 	if (get_rl_from_function(expr, &rl))
458 		return 1;
459 
460 	if (expr->type == EXPR_BINOP && expr->op == '+') {
461 		if (points_to_user_data(expr->left))
462 			return 1;
463 		if (points_to_user_data(expr->right))
464 			return 1;
465 		return 0;
466 	}
467 
468 	name = expr_to_var_sym(expr, &sym);
469 	if (!name || !sym)
470 		goto free;
471 	snprintf(buf, sizeof(buf), "*%s", name);
472 	state = __get_state(my_id, buf, sym);
473 	if (state && estate_rl(state))
474 		ret = 1;
475 free:
476 	free_string(name);
477 	return ret;
478 }
479 
set_points_to_user_data(struct expression * expr)480 static void set_points_to_user_data(struct expression *expr)
481 {
482 	char *name;
483 	struct symbol *sym;
484 	char buf[256];
485 	struct symbol *type;
486 
487 	name = expr_to_var_sym(expr, &sym);
488 	if (!name || !sym)
489 		goto free;
490 	snprintf(buf, sizeof(buf), "*%s", name);
491 	type = get_type(expr);
492 	if (type && type->type == SYM_PTR)
493 		type = get_real_base_type(type);
494 	if (!type || type->type != SYM_BASETYPE)
495 		type = &llong_ctype;
496 	set_state(my_id, buf, sym, alloc_estate_whole(type));
497 free:
498 	free_string(name);
499 }
500 
comes_from_skb_data(struct expression * expr)501 static int comes_from_skb_data(struct expression *expr)
502 {
503 	expr = strip_expr(expr);
504 	if (!expr || expr->type != EXPR_PREOP || expr->op != '*')
505 		return 0;
506 
507 	expr = strip_expr(expr->unop);
508 	if (!expr)
509 		return 0;
510 	if (expr->type == EXPR_BINOP && expr->op == '+')
511 		expr = strip_expr(expr->left);
512 
513 	return is_skb_data(expr);
514 }
515 
handle_struct_assignment(struct expression * expr)516 static int handle_struct_assignment(struct expression *expr)
517 {
518 	struct expression *right;
519 	struct symbol *left_type, *right_type;
520 
521 	left_type = get_type(expr->left);
522 	if (!left_type || left_type->type != SYM_PTR)
523 		return 0;
524 	left_type = get_real_base_type(left_type);
525 	if (!left_type)
526 		return 0;
527 	if (left_type->type != SYM_STRUCT &&
528 	    left_type->type != SYM_UNION)
529 		return 0;
530 
531 	/*
532 	 * Ignore struct to struct assignments because for those we look at the
533 	 * individual members.
534 	 */
535 	right = strip_expr(expr->right);
536 	right_type = get_type(right);
537 	if (!right_type || right_type->type != SYM_PTR)
538 		return 0;
539 
540 	/* If we are assigning struct members then normally that is handled
541 	 * by fake assignments, however if we cast one struct to a different
542 	 * of struct then we handle that here.
543 	 */
544 	right_type = get_real_base_type(right_type);
545 	if (right_type == left_type)
546 		return 0;
547 
548 	if (!points_to_user_data(right))
549 		return 0;
550 
551 	tag_as_user_data(expr->left);
552 	return 1;
553 }
554 
handle_get_user(struct expression * expr)555 static int handle_get_user(struct expression *expr)
556 {
557 	char *name;
558 	int ret = 0;
559 
560 	name = get_macro_name(expr->pos);
561 	if (!name || strcmp(name, "get_user") != 0)
562 		return 0;
563 
564 	name = expr_to_var(expr->right);
565 	if (!name || (strcmp(name, "__val_gu") != 0 && strcmp(name, "__gu_val") != 0))
566 		goto free;
567 	set_state_expr(my_id, expr->left, alloc_estate_whole(get_type(expr->left)));
568 	ret = 1;
569 free:
570 	free_string(name);
571 	return ret;
572 }
573 
handle_op_assign(struct expression * expr)574 static bool handle_op_assign(struct expression *expr)
575 {
576 	struct expression *binop_expr;
577 	struct smatch_state *state;
578 	struct range_list *rl;
579 
580 	switch (expr->op) {
581 	case SPECIAL_ADD_ASSIGN:
582 	case SPECIAL_SUB_ASSIGN:
583 	case SPECIAL_AND_ASSIGN:
584 	case SPECIAL_MOD_ASSIGN:
585 	case SPECIAL_SHL_ASSIGN:
586 	case SPECIAL_SHR_ASSIGN:
587 	case SPECIAL_OR_ASSIGN:
588 	case SPECIAL_XOR_ASSIGN:
589 	case SPECIAL_MUL_ASSIGN:
590 	case SPECIAL_DIV_ASSIGN:
591 		binop_expr = binop_expression(expr->left,
592 					      op_remove_assign(expr->op),
593 					      expr->right);
594 		if (!get_user_rl(binop_expr, &rl))
595 			return true;
596 
597 		rl = cast_rl(get_type(expr->left), rl);
598 		state = alloc_estate_rl(rl);
599 		if (user_rl_capped(binop_expr))
600 			estate_set_capped(state);
601 		if (user_rl_treat_untagged(expr->left))
602 			estate_set_treat_untagged(state);
603 		set_state_expr(my_id, expr->left, state);
604 		return true;
605 	}
606 	return false;
607 }
608 
match_assign(struct expression * expr)609 static void match_assign(struct expression *expr)
610 {
611 	struct range_list *rl;
612 	static struct expression *handled;
613 	struct smatch_state *state;
614 	struct expression *faked;
615 
616 	faked = get_faked_expression();
617 	if (faked && faked == handled)
618 		return;
619 	if (is_fake_call(expr->right))
620 		goto clear_old_state;
621 	if (handle_get_user(expr))
622 		return;
623 	if (points_to_user_data(expr->right)) {
624 		handled = expr;
625 		set_points_to_user_data(expr->left);
626 	}
627 	if (handle_struct_assignment(expr))
628 		return;
629 
630 	if (handle_op_assign(expr))
631 		return;
632 	if (expr->op != '=')
633 		goto clear_old_state;
634 
635 	/* Handled by DB code */
636 	if (expr->right->type == EXPR_CALL || __in_fake_parameter_assign)
637 		return;
638 
639 	if (!get_user_rl(expr->right, &rl))
640 		goto clear_old_state;
641 
642 	rl = cast_rl(get_type(expr->left), rl);
643 	state = alloc_estate_rl(rl);
644 
645 	if (user_rl_capped(expr->right))
646 		estate_set_capped(state);
647 	if (user_rl_treat_untagged(expr->right))
648 		estate_set_treat_untagged(state);
649 	set_state_expr(my_id, expr->left, state);
650 
651 	return;
652 
653 clear_old_state:
654 	if (get_state_expr(my_id, expr->left))
655 		set_state_expr(my_id, expr->left, alloc_estate_empty());
656 }
657 
handle_eq_noteq(struct expression * expr)658 static void handle_eq_noteq(struct expression *expr)
659 {
660 	struct smatch_state *left_orig, *right_orig;
661 
662 	left_orig = get_state_expr(my_id, expr->left);
663 	right_orig = get_state_expr(my_id, expr->right);
664 
665 	if (!left_orig && !right_orig)
666 		return;
667 	if (left_orig && right_orig)
668 		return;
669 
670 	if (left_orig) {
671 		set_true_false_states_expr(my_id, expr->left,
672 				expr->op == SPECIAL_EQUAL ? alloc_estate_empty() : NULL,
673 				expr->op == SPECIAL_EQUAL ? NULL : alloc_estate_empty());
674 	} else {
675 		set_true_false_states_expr(my_id, expr->right,
676 				expr->op == SPECIAL_EQUAL ? alloc_estate_empty() : NULL,
677 				expr->op == SPECIAL_EQUAL ? NULL : alloc_estate_empty());
678 	}
679 }
680 
strip_negatives(struct range_list * rl)681 static struct range_list *strip_negatives(struct range_list *rl)
682 {
683 	sval_t min = rl_min(rl);
684 	sval_t minus_one;
685 	sval_t over;
686 	sval_t max = sval_type_max(rl_type(rl));
687 
688 	minus_one.type = rl_type(rl);
689 	minus_one.value = -1;
690 	over.type = rl_type(rl);
691 	over.value = INT_MAX + 1ULL;
692 
693 	if (!rl)
694 		return NULL;
695 
696 	if (type_unsigned(rl_type(rl)) && type_bits(rl_type(rl)) > 31)
697 		return remove_range(rl, over, max);
698 
699 	return remove_range(rl, min, minus_one);
700 }
701 
handle_compare(struct expression * expr)702 static void handle_compare(struct expression *expr)
703 {
704 	struct expression  *left, *right;
705 	struct range_list *left_rl = NULL;
706 	struct range_list *right_rl = NULL;
707 	struct range_list *user_rl;
708 	struct smatch_state *capped_state;
709 	struct smatch_state *left_true = NULL;
710 	struct smatch_state *left_false = NULL;
711 	struct smatch_state *right_true = NULL;
712 	struct smatch_state *right_false = NULL;
713 	struct symbol *type;
714 	sval_t sval;
715 
716 	left = strip_expr(expr->left);
717 	right = strip_expr(expr->right);
718 
719 	while (left->type == EXPR_ASSIGNMENT)
720 		left = strip_expr(left->left);
721 
722 	/*
723 	 * Conditions are mostly handled by smatch_extra.c, but there are some
724 	 * times where the exact values are not known so we can't do that.
725 	 *
726 	 * Normally, we might consider using smatch_capped.c to supliment smatch
727 	 * extra but that doesn't work when we merge unknown uncapped kernel
728 	 * data with unknown capped user data.  The result is uncapped user
729 	 * data.  We need to keep it separate and say that the user data is
730 	 * capped.  In the past, I would have marked this as just regular
731 	 * kernel data (not user data) but we can't do that these days because
732 	 * we need to track user data for Spectre.
733 	 *
734 	 * The other situation which we have to handle is when we do have an
735 	 * int and we compare against an unknown unsigned kernel variable.  In
736 	 * that situation we assume that the kernel data is less than INT_MAX.
737 	 * Otherwise then we get all sorts of array underflow false positives.
738 	 *
739 	 */
740 
741 	/* Handled in smatch_extra.c */
742 	if (get_implied_value(left, &sval) ||
743 	    get_implied_value(right, &sval))
744 		return;
745 
746 	get_user_rl(left, &left_rl);
747 	get_user_rl(right, &right_rl);
748 
749 	/* nothing to do */
750 	if (!left_rl && !right_rl)
751 		return;
752 	/* if both sides are user data that's not a good limit */
753 	if (left_rl && right_rl)
754 		return;
755 
756 	if (left_rl)
757 		user_rl = left_rl;
758 	else
759 		user_rl = right_rl;
760 
761 	type = get_type(expr);
762 	if (type_unsigned(type))
763 		user_rl = strip_negatives(user_rl);
764 	capped_state = alloc_estate_rl(user_rl);
765 	estate_set_capped(capped_state);
766 
767 	switch (expr->op) {
768 	case '<':
769 	case SPECIAL_UNSIGNED_LT:
770 	case SPECIAL_LTE:
771 	case SPECIAL_UNSIGNED_LTE:
772 		if (left_rl)
773 			left_true = capped_state;
774 		else
775 			right_false = capped_state;
776 		break;
777 	case '>':
778 	case SPECIAL_UNSIGNED_GT:
779 	case SPECIAL_GTE:
780 	case SPECIAL_UNSIGNED_GTE:
781 		if (left_rl)
782 			left_false = capped_state;
783 		else
784 			right_true = capped_state;
785 		break;
786 	}
787 
788 	set_true_false_states_expr(my_id, left, left_true, left_false);
789 	set_true_false_states_expr(my_id, right, right_true, right_false);
790 }
791 
match_condition(struct expression * expr)792 static void match_condition(struct expression *expr)
793 {
794 	if (expr->type != EXPR_COMPARE)
795 		return;
796 
797 	if (expr->op == SPECIAL_EQUAL ||
798 	    expr->op == SPECIAL_NOTEQUAL) {
799 		handle_eq_noteq(expr);
800 		return;
801 	}
802 
803 	handle_compare(expr);
804 }
805 
match_user_assign_function(const char * fn,struct expression * expr,void * unused)806 static void match_user_assign_function(const char *fn, struct expression *expr, void *unused)
807 {
808 	tag_as_user_data(expr->left);
809 	set_points_to_user_data(expr->left);
810 }
811 
match_returns_user_rl(const char * fn,struct expression * expr,void * unused)812 static void match_returns_user_rl(const char *fn, struct expression *expr, void *unused)
813 {
814 	func_gets_user_data = true;
815 }
816 
get_user_macro_rl(struct expression * expr,struct range_list ** rl)817 static int get_user_macro_rl(struct expression *expr, struct range_list **rl)
818 {
819 	struct expression *parent;
820 	char *macro;
821 
822 	if (!expr)
823 		return 0;
824 
825 	macro = get_macro_name(expr->pos);
826 	if (!macro)
827 		return 0;
828 
829 	/* handle ntohl(foo[i]) where "i" is trusted */
830 	parent = expr_get_parent_expr(expr);
831 	while (parent && parent->type != EXPR_BINOP)
832 		parent = expr_get_parent_expr(parent);
833 	if (parent && parent->type == EXPR_BINOP) {
834 		char *parent_macro = get_macro_name(parent->pos);
835 
836 		if (parent_macro && strcmp(macro, parent_macro) == 0)
837 			return 0;
838 	}
839 
840 	if (strcmp(macro, "ntohl") == 0) {
841 		*rl = alloc_whole_rl(&uint_ctype);
842 		return 1;
843 	}
844 	if (strcmp(macro, "ntohs") == 0) {
845 		*rl = alloc_whole_rl(&ushort_ctype);
846 		return 1;
847 	}
848 	return 0;
849 }
850 
has_user_data(struct symbol * sym)851 static int has_user_data(struct symbol *sym)
852 {
853 	struct sm_state *tmp;
854 
855 	FOR_EACH_MY_SM(my_id, __get_cur_stree(), tmp) {
856 		if (tmp->sym == sym)
857 			return 1;
858 	} END_FOR_EACH_SM(tmp);
859 	return 0;
860 }
861 
we_pass_user_data(struct expression * call)862 static int we_pass_user_data(struct expression *call)
863 {
864 	struct expression *arg;
865 	struct symbol *sym;
866 
867 	FOR_EACH_PTR(call->args, arg) {
868 		sym = expr_to_sym(arg);
869 		if (!sym)
870 			continue;
871 		if (has_user_data(sym))
872 			return 1;
873 	} END_FOR_EACH_PTR(arg);
874 
875 	return 0;
876 }
877 
db_returned_user_rl(struct expression * call,struct range_list ** rl)878 static int db_returned_user_rl(struct expression *call, struct range_list **rl)
879 {
880 	struct smatch_state *state;
881 	char buf[48];
882 
883 	if (is_fake_call(call))
884 		return 0;
885 	snprintf(buf, sizeof(buf), "return %p", call);
886 	state = get_state(my_id, buf, NULL);
887 	if (!state || !estate_rl(state))
888 		return 0;
889 	*rl = estate_rl(state);
890 	return 1;
891 }
892 
get_user_stree(void)893 struct stree *get_user_stree(void)
894 {
895 	return get_all_states_stree(my_id);
896 }
897 
898 static int user_data_flag;
899 static int no_user_data_flag;
var_user_rl(struct expression * expr)900 struct range_list *var_user_rl(struct expression *expr)
901 {
902 	struct smatch_state *state;
903 	struct range_list *rl;
904 	struct range_list *absolute_rl;
905 
906 	if (expr->type == EXPR_PREOP && expr->op == '&') {
907 		no_user_data_flag = 1;
908 		return NULL;
909 	}
910 
911 	if (expr->type == EXPR_BINOP && expr->op == '%') {
912 		struct range_list *left, *right;
913 
914 		if (!get_user_rl(expr->right, &right))
915 			return NULL;
916 		get_absolute_rl(expr->left, &left);
917 		rl = rl_binop(left, '%', right);
918 		goto found;
919 	}
920 
921 	if (expr->type == EXPR_BINOP && expr->op == '/') {
922 		struct range_list *left = NULL;
923 		struct range_list *right = NULL;
924 		struct range_list *abs_right;
925 
926 		/*
927 		 * The specific bug I'm dealing with is:
928 		 *
929 		 * foo = capped_user / unknown;
930 		 *
931 		 * Instead of just saying foo is now entirely user_rl we should
932 		 * probably say instead that it is not at all user data.
933 		 *
934 		 */
935 
936 		get_user_rl(expr->left, &left);
937 		get_user_rl(expr->right, &right);
938 		get_absolute_rl(expr->right, &abs_right);
939 
940 		if (left && !right) {
941 			rl = rl_binop(left, '/', abs_right);
942 			if (sval_cmp(rl_max(left), rl_max(rl)) < 0)
943 				no_user_data_flag = 1;
944 		}
945 
946 		return NULL;
947 	}
948 
949 	if (get_rl_from_function(expr, &rl))
950 		goto found;
951 
952 	if (get_user_macro_rl(expr, &rl))
953 		goto found;
954 
955 	if (comes_from_skb_data(expr)) {
956 		rl = alloc_whole_rl(get_type(expr));
957 		goto found;
958 	}
959 
960 	state = get_state_expr(my_id, expr);
961 	if (state && estate_rl(state)) {
962 		rl = estate_rl(state);
963 		goto found;
964 	}
965 
966 	if (expr->type == EXPR_CALL && db_returned_user_rl(expr, &rl))
967 		goto found;
968 
969 	if (is_array(expr)) {
970 		struct expression *array = get_array_base(expr);
971 
972 		if (!get_state_expr(my_id, array)) {
973 			no_user_data_flag = 1;
974 			return NULL;
975 		}
976 	}
977 
978 	if (expr->type == EXPR_PREOP && expr->op == '*' &&
979 	    is_user_rl(expr->unop)) {
980 		rl = var_to_absolute_rl(expr);
981 		goto found;
982 	}
983 
984 	return NULL;
985 found:
986 	user_data_flag = 1;
987 	absolute_rl = var_to_absolute_rl(expr);
988 	return clone_rl(rl_intersection(rl, absolute_rl));
989 }
990 
is_ptr_subtract(struct expression * expr)991 static bool is_ptr_subtract(struct expression *expr)
992 {
993 	expr = strip_expr(expr);
994 	if (!expr)
995 		return false;
996 	if (expr->type == EXPR_BINOP && expr->op == '-' &&
997 	    type_is_ptr(get_type(expr->left))) {
998 		return true;
999 	}
1000 	return false;
1001 }
1002 
get_user_rl(struct expression * expr,struct range_list ** rl)1003 int get_user_rl(struct expression *expr, struct range_list **rl)
1004 {
1005 	if (is_ptr_subtract(expr))
1006 		return 0;
1007 
1008 	user_data_flag = 0;
1009 	no_user_data_flag = 0;
1010 	custom_get_absolute_rl(expr, &var_user_rl, rl);
1011 	if (!user_data_flag || no_user_data_flag)
1012 		*rl = NULL;
1013 
1014 	return !!*rl;
1015 }
1016 
is_user_rl(struct expression * expr)1017 int is_user_rl(struct expression *expr)
1018 {
1019 	struct range_list *tmp;
1020 
1021 	return !!get_user_rl(expr, &tmp);
1022 }
1023 
get_user_rl_var_sym(const char * name,struct symbol * sym,struct range_list ** rl)1024 int get_user_rl_var_sym(const char *name, struct symbol *sym, struct range_list **rl)
1025 {
1026 	struct smatch_state *state;
1027 
1028 	state = get_state(my_id, name, sym);
1029 	if (state && estate_rl(state)) {
1030 		*rl = estate_rl(state);
1031 		return 1;
1032 	}
1033 	return 0;
1034 }
1035 
get_user_rl_str(struct expression * expr,struct symbol * type)1036 static char *get_user_rl_str(struct expression *expr, struct symbol *type)
1037 {
1038 	struct range_list *rl;
1039 	static char buf[64];
1040 
1041 	if (!get_user_rl(expr, &rl))
1042 		return NULL;
1043 	rl = cast_rl(type, rl);
1044 	snprintf(buf, sizeof(buf), "%s%s%s",
1045 		 show_rl(rl),
1046 		 user_rl_capped(expr) ? "[c]" : "",
1047 		 user_rl_treat_untagged(expr) ? "[u]" : "");
1048 	return buf;
1049 }
1050 
match_call_info(struct expression * expr)1051 static void match_call_info(struct expression *expr)
1052 {
1053 	struct expression *arg;
1054 	struct symbol *type;
1055 	char *str;
1056 	int i;
1057 
1058 	i = -1;
1059 	FOR_EACH_PTR(expr->args, arg) {
1060 		i++;
1061 		type = get_arg_type(expr->fn, i);
1062 		str = get_user_rl_str(arg, type);
1063 		if (!str)
1064 			continue;
1065 
1066 		sql_insert_caller_info(expr, USER_DATA, i, "$", str);
1067 	} END_FOR_EACH_PTR(arg);
1068 }
1069 
struct_member_callback(struct expression * call,int param,char * printed_name,struct sm_state * sm)1070 static void struct_member_callback(struct expression *call, int param, char *printed_name, struct sm_state *sm)
1071 {
1072 	struct smatch_state *state;
1073 	struct range_list *rl;
1074 	struct symbol *type;
1075 	char buf[64];
1076 
1077 	/*
1078 	 * Smatch uses a hack where if we get an unsigned long we say it's
1079 	 * both user data and it points to user data.  But if we pass it to a
1080 	 * function which takes an int, then it's just user data.  There's not
1081 	 * enough bytes for it to be a pointer.
1082 	 *
1083 	 */
1084 	type = get_arg_type(call->fn, param);
1085 	if (type && type_bits(type) < type_bits(&ptr_ctype))
1086 		return;
1087 
1088 	if (strcmp(sm->state->name, "") == 0)
1089 		return;
1090 
1091 	if (strcmp(printed_name, "*$") == 0 &&
1092 	    is_struct_ptr(sm->sym))
1093 		return;
1094 
1095 	state = __get_state(SMATCH_EXTRA, sm->name, sm->sym);
1096 	if (!state || !estate_rl(state))
1097 		rl = estate_rl(sm->state);
1098 	else
1099 		rl = rl_intersection(estate_rl(sm->state), estate_rl(state));
1100 
1101 	if (!rl)
1102 		return;
1103 
1104 	snprintf(buf, sizeof(buf), "%s%s%s", show_rl(rl),
1105 		 estate_capped(sm->state) ? "[c]" : "",
1106 		 estate_treat_untagged(sm->state) ? "[u]" : "");
1107 	sql_insert_caller_info(call, USER_DATA, param, printed_name, buf);
1108 }
1109 
db_param_set(struct expression * expr,int param,char * key,char * value)1110 static void db_param_set(struct expression *expr, int param, char *key, char *value)
1111 {
1112 	struct expression *arg;
1113 	char *name;
1114 	struct symbol *sym;
1115 	struct smatch_state *state;
1116 
1117 	while (expr->type == EXPR_ASSIGNMENT)
1118 		expr = strip_expr(expr->right);
1119 	if (expr->type != EXPR_CALL)
1120 		return;
1121 
1122 	arg = get_argument_from_call_expr(expr->args, param);
1123 	if (!arg)
1124 		return;
1125 	name = get_variable_from_key(arg, key, &sym);
1126 	if (!name || !sym)
1127 		goto free;
1128 
1129 	state = get_state(my_id, name, sym);
1130 	if (!state)
1131 		goto free;
1132 
1133 	set_state(my_id, name, sym, alloc_estate_empty());
1134 free:
1135 	free_string(name);
1136 }
1137 
param_data_capped(const char * value)1138 static bool param_data_capped(const char *value)
1139 {
1140 	if (strstr(value, ",c") || strstr(value, "[c"))
1141 		return true;
1142 	return false;
1143 }
1144 
param_data_treat_untagged(const char * value)1145 static bool param_data_treat_untagged(const char *value)
1146 {
1147 	if (strstr(value, ",u") || strstr(value, "[u"))
1148 		return true;
1149 	return false;
1150 }
1151 
set_param_user_data(const char * name,struct symbol * sym,char * key,char * value)1152 static void set_param_user_data(const char *name, struct symbol *sym, char *key, char *value)
1153 {
1154 	struct range_list *rl = NULL;
1155 	struct smatch_state *state;
1156 	struct expression *expr;
1157 	struct symbol *type;
1158 	char fullname[256];
1159 	char *key_orig = key;
1160 	bool add_star = false;
1161 
1162 	if (strcmp(key, "**$") == 0) {
1163 		snprintf(fullname, sizeof(fullname), "**%s", name);
1164 	} else {
1165 		if (key[0] == '*') {
1166 			add_star = true;
1167 			key++;
1168 		}
1169 
1170 		snprintf(fullname, 256, "%s%s%s", add_star ? "*" : "", name, key + 1);
1171 	}
1172 
1173 	expr = symbol_expression(sym);
1174 	type = get_member_type_from_key(expr, key_orig);
1175 
1176 	/*
1177 	 * Say this function takes a struct ponter but the caller passes
1178 	 * this_function(skb->data).  We have two options, we could pass *$
1179 	 * as user data or we could pass foo->bar, foo->baz as user data.
1180 	 * The second option is easier to implement so we do that.
1181 	 *
1182 	 */
1183 	if (strcmp(key_orig, "*$") == 0) {
1184 		struct symbol *tmp = type;
1185 
1186 		while (tmp && tmp->type == SYM_PTR)
1187 			tmp = get_real_base_type(tmp);
1188 
1189 		if (tmp && (tmp->type == SYM_STRUCT || tmp->type == SYM_UNION)) {
1190 			tag_as_user_data(symbol_expression(sym));
1191 			return;
1192 		}
1193 	}
1194 
1195 	str_to_rl(type, value, &rl);
1196 	state = alloc_estate_rl(rl);
1197 	if (param_data_capped(value) || is_capped(expr))
1198 		estate_set_capped(state);
1199 	if (param_data_treat_untagged(value) || sym->ctype.as == 5)
1200 		estate_set_treat_untagged(state);
1201 	set_state(my_id, fullname, sym, state);
1202 }
1203 
set_called(const char * name,struct symbol * sym,char * key,char * value)1204 static void set_called(const char *name, struct symbol *sym, char *key, char *value)
1205 {
1206 	set_state(my_call_id, "this_function", NULL, &called);
1207 }
1208 
match_syscall_definition(struct symbol * sym)1209 static void match_syscall_definition(struct symbol *sym)
1210 {
1211 	struct symbol *arg;
1212 	char *macro;
1213 	char *name;
1214 	int is_syscall = 0;
1215 
1216 	macro = get_macro_name(sym->pos);
1217 	if (macro &&
1218 	    (strncmp("SYSCALL_DEFINE", macro, strlen("SYSCALL_DEFINE")) == 0 ||
1219 	     strncmp("COMPAT_SYSCALL_DEFINE", macro, strlen("COMPAT_SYSCALL_DEFINE")) == 0))
1220 		is_syscall = 1;
1221 
1222 	name = get_function();
1223 	if (!option_no_db && get_state(my_call_id, "this_function", NULL) != &called) {
1224 		if (name && strncmp(name, "sys_", 4) == 0)
1225 			is_syscall = 1;
1226 	}
1227 
1228 	if (name && strncmp(name, "compat_sys_", 11) == 0)
1229 		is_syscall = 1;
1230 
1231 	if (!is_syscall)
1232 		return;
1233 
1234 	FOR_EACH_PTR(sym->ctype.base_type->arguments, arg) {
1235 		set_state(my_id, arg->ident->name, arg, alloc_estate_whole(get_real_base_type(arg)));
1236 	} END_FOR_EACH_PTR(arg);
1237 }
1238 
store_user_data_return(struct expression * expr,char * key,char * value)1239 static void store_user_data_return(struct expression *expr, char *key, char *value)
1240 {
1241 	struct range_list *rl;
1242 	struct symbol *type;
1243 	char buf[48];
1244 
1245 	if (strcmp(key, "$") != 0)
1246 		return;
1247 
1248 	type = get_type(expr);
1249 	snprintf(buf, sizeof(buf), "return %p", expr);
1250 	call_results_to_rl(expr, type, value, &rl);
1251 
1252 	set_state(my_id, buf, NULL, alloc_estate_rl(rl));
1253 }
1254 
set_to_user_data(struct expression * expr,char * key,char * value)1255 static void set_to_user_data(struct expression *expr, char *key, char *value)
1256 {
1257 	struct smatch_state *state;
1258 	char *name;
1259 	struct symbol *sym;
1260 	struct symbol *type;
1261 	struct range_list *rl = NULL;
1262 
1263 	type = get_member_type_from_key(expr, key);
1264 	name = get_variable_from_key(expr, key, &sym);
1265 	if (!name || !sym)
1266 		goto free;
1267 
1268 	call_results_to_rl(expr, type, value, &rl);
1269 
1270 	state = alloc_estate_rl(rl);
1271 	if (param_data_capped(value))
1272 		estate_set_capped(state);
1273 	if (param_data_treat_untagged(value))
1274 		estate_set_treat_untagged(state);
1275 	set_state(my_id, name, sym, state);
1276 free:
1277 	free_string(name);
1278 }
1279 
returns_param_user_data(struct expression * expr,int param,char * key,char * value)1280 static void returns_param_user_data(struct expression *expr, int param, char *key, char *value)
1281 {
1282 	struct expression *arg;
1283 	struct expression *call;
1284 
1285 	call = expr;
1286 	while (call->type == EXPR_ASSIGNMENT)
1287 		call = strip_expr(call->right);
1288 	if (call->type != EXPR_CALL)
1289 		return;
1290 
1291 	if (!we_pass_user_data(call))
1292 		return;
1293 
1294 	if (param == -1) {
1295 		if (expr->type != EXPR_ASSIGNMENT) {
1296 			store_user_data_return(expr, key, value);
1297 			return;
1298 		}
1299 		set_to_user_data(expr->left, key, value);
1300 		return;
1301 	}
1302 
1303 	arg = get_argument_from_call_expr(call->args, param);
1304 	if (!arg)
1305 		return;
1306 	set_to_user_data(arg, key, value);
1307 }
1308 
returns_param_user_data_set(struct expression * expr,int param,char * key,char * value)1309 static void returns_param_user_data_set(struct expression *expr, int param, char *key, char *value)
1310 {
1311 	struct expression *arg;
1312 
1313 	func_gets_user_data = true;
1314 
1315 	if (param == -1) {
1316 		if (expr->type != EXPR_ASSIGNMENT) {
1317 			store_user_data_return(expr, key, value);
1318 			return;
1319 		}
1320 		if (strcmp(key, "*$") == 0) {
1321 			set_points_to_user_data(expr->left);
1322 			tag_as_user_data(expr->left);
1323 		} else {
1324 			set_to_user_data(expr->left, key, value);
1325 		}
1326 		return;
1327 	}
1328 
1329 	while (expr->type == EXPR_ASSIGNMENT)
1330 		expr = strip_expr(expr->right);
1331 	if (expr->type != EXPR_CALL)
1332 		return;
1333 
1334 	arg = get_argument_from_call_expr(expr->args, param);
1335 	if (!arg)
1336 		return;
1337 	set_to_user_data(arg, key, value);
1338 }
1339 
param_set_to_user_data(int return_id,char * return_ranges,struct expression * expr)1340 static void param_set_to_user_data(int return_id, char *return_ranges, struct expression *expr)
1341 {
1342 	struct sm_state *sm;
1343 	struct smatch_state *start_state;
1344 	struct range_list *rl;
1345 	int param;
1346 	char *return_str;
1347 	const char *param_name;
1348 	struct symbol *ret_sym;
1349 	bool return_found = false;
1350 	bool pointed_at_found = false;
1351 	char buf[64];
1352 
1353 	expr = strip_expr(expr);
1354 	return_str = expr_to_str(expr);
1355 	ret_sym = expr_to_sym(expr);
1356 
1357 	FOR_EACH_MY_SM(my_id, __get_cur_stree(), sm) {
1358 		param = get_param_num_from_sym(sm->sym);
1359 		if (param < 0)
1360 			continue;
1361 
1362 		if (!param_was_set_var_sym(sm->name, sm->sym))
1363 			continue;
1364 
1365 		/* The logic here was that if we were passed in a user data then
1366 		 * we don't record that.  It's like the difference between
1367 		 * param_filter and param_set.  When I think about it, I'm not
1368 		 * sure it actually works.  It's probably harmless because we
1369 		 * checked earlier that we're not returning a parameter...
1370 		 * Let's mark this as a TODO.
1371 		 */
1372 		start_state = get_state_stree(start_states, my_id, sm->name, sm->sym);
1373 		if (start_state && rl_equiv(estate_rl(sm->state), estate_rl(start_state)))
1374 			continue;
1375 
1376 		param_name = get_param_name(sm);
1377 		if (!param_name)
1378 			continue;
1379 		if (strcmp(param_name, "$") == 0)  /* The -1 param is handled after the loop */
1380 			continue;
1381 
1382 		snprintf(buf, sizeof(buf), "%s%s%s",
1383 			 show_rl(estate_rl(sm->state)),
1384 			 estate_capped(sm->state) ? "[c]" : "",
1385 			 estate_treat_untagged(sm->state) ? "[u]" : "");
1386 		sql_insert_return_states(return_id, return_ranges,
1387 					 func_gets_user_data ? USER_DATA_SET : USER_DATA,
1388 					 param, param_name, buf);
1389 	} END_FOR_EACH_SM(sm);
1390 
1391 	/* This if for "return foo;" where "foo->bar" is user data. */
1392 	FOR_EACH_MY_SM(my_id, __get_cur_stree(), sm) {
1393 		if (!ret_sym)
1394 			break;
1395 		if (ret_sym != sm->sym)
1396 			continue;
1397 
1398 		param_name = state_name_to_param_name(sm->name, return_str);
1399 		if (!param_name)
1400 			continue;
1401 		if (strcmp(param_name, "$") == 0)
1402 			return_found = true;
1403 		if (strcmp(param_name, "*$") == 0)
1404 			pointed_at_found = true;
1405 		snprintf(buf, sizeof(buf), "%s%s%s",
1406 			 show_rl(estate_rl(sm->state)),
1407 			 estate_capped(sm->state) ? "[c]" : "",
1408 			 estate_treat_untagged(sm->state) ? "[u]" : "");
1409 		sql_insert_return_states(return_id, return_ranges,
1410 					 func_gets_user_data ? USER_DATA_SET : USER_DATA,
1411 					 -1, param_name, buf);
1412 	} END_FOR_EACH_SM(sm);
1413 
1414 	/* This if for "return ntohl(foo);" */
1415 	if (!return_found && get_user_rl(expr, &rl)) {
1416 		snprintf(buf, sizeof(buf), "%s%s%s",
1417 			 show_rl(rl),
1418 			 user_rl_capped(expr) ? "[c]" : "",
1419 			 user_rl_treat_untagged(expr) ? "[u]" : "");
1420 		sql_insert_return_states(return_id, return_ranges,
1421 					 func_gets_user_data ? USER_DATA_SET : USER_DATA,
1422 					 -1, "$", buf);
1423 	}
1424 
1425 	/*
1426 	 * This is to handle things like return skb->data where we don't set a
1427 	 * state for that.
1428 	 */
1429 	if (!pointed_at_found && points_to_user_data(expr)) {
1430 		sql_insert_return_states(return_id, return_ranges,
1431 					 (is_skb_data(expr) || func_gets_user_data) ?
1432 					 USER_DATA_SET : USER_DATA,
1433 					 -1, "*$", "s64min-s64max");
1434 	}
1435 
1436 	free_string(return_str);
1437 }
1438 
returns_param_capped(struct expression * expr,int param,char * key,char * value)1439 static void returns_param_capped(struct expression *expr, int param, char *key, char *value)
1440 {
1441 	struct smatch_state *state, *new;
1442 	struct symbol *sym;
1443 	char *name;
1444 
1445 	name = return_state_to_var_sym(expr, param, key, &sym);
1446 	if (!name || !sym)
1447 		goto free;
1448 
1449 	state = get_state(my_id, name, sym);
1450 	if (!state || estate_capped(state))
1451 		goto free;
1452 
1453 	new = clone_estate(state);
1454 	estate_set_capped(new);
1455 
1456 	set_state(my_id, name, sym, new);
1457 free:
1458 	free_string(name);
1459 }
1460 
1461 static struct int_stack *gets_data_stack;
match_function_def(struct symbol * sym)1462 static void match_function_def(struct symbol *sym)
1463 {
1464 	func_gets_user_data = false;
1465 }
1466 
match_inline_start(struct expression * expr)1467 static void match_inline_start(struct expression *expr)
1468 {
1469 	push_int(&gets_data_stack, func_gets_user_data);
1470 }
1471 
match_inline_end(struct expression * expr)1472 static void match_inline_end(struct expression *expr)
1473 {
1474 	func_gets_user_data = pop_int(&gets_data_stack);
1475 }
1476 
register_kernel_user_data(int id)1477 void register_kernel_user_data(int id)
1478 {
1479 	int i;
1480 
1481 	my_id = id;
1482 
1483 	if (option_project != PROJ_KERNEL)
1484 		return;
1485 
1486 	set_dynamic_states(my_id);
1487 
1488 	add_hook(&match_function_def, FUNC_DEF_HOOK);
1489 	add_hook(&match_inline_start, INLINE_FN_START);
1490 	add_hook(&match_inline_end, INLINE_FN_END);
1491 
1492 	add_hook(&save_start_states, AFTER_DEF_HOOK);
1493 	add_hook(&free_start_states, AFTER_FUNC_HOOK);
1494 	add_hook(&match_save_states, INLINE_FN_START);
1495 	add_hook(&match_restore_states, INLINE_FN_END);
1496 
1497 	add_unmatched_state_hook(my_id, &empty_state);
1498 	add_extra_nomod_hook(&extra_nomod_hook);
1499 	add_pre_merge_hook(my_id, &pre_merge_hook);
1500 	add_merge_hook(my_id, &merge_estates);
1501 
1502 	add_function_hook("copy_from_user", &match_user_copy, INT_PTR(0));
1503 	add_function_hook("__copy_from_user", &match_user_copy, INT_PTR(0));
1504 	add_function_hook("memcpy_fromiovec", &match_user_copy, INT_PTR(0));
1505 	for (i = 0; i < ARRAY_SIZE(kstr_funcs); i++)
1506 		add_function_hook(kstr_funcs[i], &match_user_copy, INT_PTR(2));
1507 	add_function_hook("usb_control_msg", &match_user_copy, INT_PTR(6));
1508 
1509 	for (i = 0; i < ARRAY_SIZE(returns_user_data); i++) {
1510 		add_function_assign_hook(returns_user_data[i], &match_user_assign_function, NULL);
1511 		add_function_hook(returns_user_data[i], &match_returns_user_rl, NULL);
1512 	}
1513 
1514 	add_function_hook("sscanf", &match_sscanf, NULL);
1515 
1516 	add_hook(&match_syscall_definition, AFTER_DEF_HOOK);
1517 
1518 	add_hook(&match_assign, ASSIGNMENT_HOOK);
1519 	select_return_states_hook(PARAM_SET, &db_param_set);
1520 	add_hook(&match_condition, CONDITION_HOOK);
1521 
1522 	add_hook(&match_call_info, FUNCTION_CALL_HOOK);
1523 	add_member_info_callback(my_id, struct_member_callback);
1524 	select_caller_info_hook(set_param_user_data, USER_DATA);
1525 	select_return_states_hook(USER_DATA, &returns_param_user_data);
1526 	select_return_states_hook(USER_DATA_SET, &returns_param_user_data_set);
1527 	select_return_states_hook(CAPPED_DATA, &returns_param_capped);
1528 	add_split_return_callback(&param_set_to_user_data);
1529 }
1530 
register_kernel_user_data2(int id)1531 void register_kernel_user_data2(int id)
1532 {
1533 	my_call_id = id;
1534 
1535 	if (option_project != PROJ_KERNEL)
1536 		return;
1537 	select_caller_info_hook(set_called, INTERNAL);
1538 }
1539 
1540