check_user_data2.c

   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
  84         extra = get_state(SMATCH_EXTRA, sm->name, sm->sym);
  85         if (!extra || !estate_rl(extra))
  86                 return;
  87         user = get_state(my_id, sm->name, sm->sym);
  88         if (!user || !estate_rl(user))
  89                 return;
  90         rl = rl_intersection(estate_rl(user), estate_rl(extra));
  91         if (rl_to_sval(rl, &dummy))
  92                 rl = NULL;
  93         set_state(my_id, sm->name, sm->sym, alloc_estate_rl(clone_rl(rl)));
  94 }
  95
  96 static void tag_inner_struct_members(struct expression *expr, struct symbol *member)
  97 {
  98         struct expression *edge_member;
  99         struct symbol *base = get_real_base_type(member);
 100         struct symbol *tmp;
 101
 102         if (member->ident)
 103                 expr = member_expression(expr, '.', member->ident);
 104
 105         FOR_EACH_PTR(base->symbol_list, tmp) {
 106                 struct symbol *type;
 107
 108                 type = get_real_base_type(tmp);
 109                 if (!type)
 110                         continue;
 111
 112                 if (type->type == SYM_UNION || type->type == SYM_STRUCT) {
 113                         tag_inner_struct_members(expr, tmp);
 114                         continue;
 115                 }
 116
 117                 if (!tmp->ident)
 118                         continue;
 119
 120                 edge_member = member_expression(expr, '.', tmp->ident);
 121                 set_state_expr(my_id, edge_member, alloc_estate_whole(type));
 122         } END_FOR_EACH_PTR(tmp);
 123 }
 124
 125 static void tag_struct_members(struct symbol *type, struct expression *expr)
 126 {
 127         struct symbol *tmp;
 128         struct expression *member;
 129         int op = '*';
 130
 131         if (expr->type == EXPR_PREOP && expr->op == '&') {
 132                 expr = strip_expr(expr->unop);
 133                 op = '.';
 134         }
 135
 136         FOR_EACH_PTR(type->symbol_list, tmp) {
 137                 type = get_real_base_type(tmp);
 138                 if (!type)
 139                         continue;
 140
 141                 if (type->type == SYM_UNION || type->type == SYM_STRUCT) {
 142                         tag_inner_struct_members(expr, tmp);
 143                         continue;
 144                 }
 145
 146                 if (!tmp->ident)
 147                         continue;
 148
 149                 member = member_expression(expr, op, tmp->ident);
 150                 set_state_expr(my_id, member, alloc_estate_whole(get_type(member)));
 151
 152                 if (type->type == SYM_ARRAY)
 153                         set_points_to_user_data(member);
 154         } END_FOR_EACH_PTR(tmp);
 155 }
 156
 157 static void tag_base_type(struct expression *expr)
 158 {
 159         if (expr->type == EXPR_PREOP && expr->op == '&')
 160                 expr = strip_expr(expr->unop);
 161         else
 162                 expr = deref_expression(expr);
 163         set_state_expr(my_id, expr, alloc_estate_whole(get_type(expr)));
 164 }
 165
 166 static void tag_as_user_data(struct expression *expr)
 167 {
 168         struct symbol *type;
 169
 170         expr = strip_expr(expr);
 171
 172         type = get_type(expr);
 173         if (!type || type->type != SYM_PTR)
 174                 return;
 175         type = get_real_base_type(type);
 176         if (!type)
 177                 return;
 178         if (type == &void_ctype) {
 179                 set_state_expr(my_id, deref_expression(expr), alloc_estate_whole(&ulong_ctype));
 180                 return;
 181         }
 182         if (type->type == SYM_BASETYPE)
 183                 tag_base_type(expr);
 184         if (type->type == SYM_STRUCT || type->type == SYM_UNION) {
 185                 if (expr->type != EXPR_PREOP || expr->op != '&')
 186                         expr = deref_expression(expr);
 187                 else
 188                         set_state_expr(my_id, deref_expression(expr), alloc_estate_whole(&ulong_ctype));
 189                 tag_struct_members(type, expr);
 190         }
 191 }
 192
 193 static void match_user_copy(const char *fn, struct expression *expr, void *_param)
 194 {
 195         int param = PTR_INT(_param);
 196         struct expression *dest;
 197
 198         func_gets_user_data = true;
 199
 200         dest = get_argument_from_call_expr(expr->args, param);
 201         dest = strip_expr(dest);
 202         if (!dest)
 203                 return;
 204         tag_as_user_data(dest);
 205 }
 206
 207 static void match_sscanf(const char *fn, struct expression *expr, void *unused)
 208 {
 209         struct expression *arg;
 210         int i;
 211
 212         func_gets_user_data = true;
 213
 214         i = -1;
 215         FOR_EACH_PTR(expr->args, arg) {
 216                 i++;
 217                 if (i < 2)
 218                         continue;
 219                 tag_as_user_data(arg);
 220         } END_FOR_EACH_PTR(arg);
 221 }
 222
 223 static int points_to_user_data(struct expression *expr)
 224 {
 225         struct smatch_state *state;
 226         char buf[256];
 227         struct symbol *sym;
 228         char *name;
 229         int ret = 0;
 230
 231         expr = strip_expr(expr);
 232
 233         if (expr->type == EXPR_BINOP && expr->op == '+') {
 234                 if (points_to_user_data(expr->left))
 235                         return 1;
 236                 if (points_to_user_data(expr->right))
 237                         return 1;
 238                 return 0;
 239         }
 240
 241         name = expr_to_var_sym(expr, &sym);
 242         if (!name || !sym)
 243                 goto free;
 244         snprintf(buf, sizeof(buf), "*%s", name);
 245         state = get_state(my_id, buf, sym);
 246         if (state && estate_rl(state))
 247                 ret = 1;
 248 free:
 249         free_string(name);
 250         return ret;
 251 }
 252
 253 static void set_points_to_user_data(struct expression *expr)
 254 {
 255         char *name;
 256         struct symbol *sym;
 257         char buf[256];
 258
 259         name = expr_to_var_sym(expr, &sym);
 260         if (!name || !sym)
 261                 goto free;
 262         snprintf(buf, sizeof(buf), "*%s", name);
 263         set_state(my_id, buf, sym, alloc_estate_whole(&llong_ctype));
 264 free:
 265         free_string(name);
 266 }
 267
 268 static int is_skb_data(struct expression *expr)
 269 {
 270         struct symbol *sym;
 271
 272         if (expr->type == EXPR_BINOP && expr->op == '+')
 273                 return is_skb_data(expr->left);
 274
 275         expr = strip_expr(expr);
 276         if (!expr)
 277                 return 0;
 278         if (expr->type != EXPR_DEREF || expr->op != '.')
 279                 return 0;
 280
 281         if (!expr->member)
 282                 return 0;
 283         if (strcmp(expr->member->name, "data") != 0)
 284                 return 0;
 285
 286         sym = expr_to_sym(expr->deref);
 287         if (!sym)
 288                 return 0;
 289         sym = get_real_base_type(sym);
 290         if (!sym || sym->type != SYM_PTR)
 291                 return 0;
 292         sym = get_real_base_type(sym);
 293         if (!sym || sym->type != SYM_STRUCT || !sym->ident)
 294                 return 0;
 295         if (strcmp(sym->ident->name, "sk_buff") != 0)
 296                 return 0;
 297
 298         return 1;
 299 }
 300
 301 static int comes_from_skb_data(struct expression *expr)
 302 {
 303         expr = strip_expr(expr);
 304         if (!expr || expr->type != EXPR_PREOP || expr->op != '*')
 305                 return 0;
 306
 307         expr = strip_expr(expr->unop);
 308         if (!expr)
 309                 return 0;
 310         if (expr->type == EXPR_BINOP && expr->op == '+')
 311                 expr = strip_expr(expr->left);
 312
 313         return is_skb_data(expr);
 314 }
 315
 316 static int handle_struct_assignment(struct expression *expr)
 317 {
 318         struct expression *right;
 319         struct symbol *left_type, *right_type;
 320
 321         left_type = get_type(expr->left);
 322         if (!left_type || left_type->type != SYM_PTR)
 323                 return 0;
 324         left_type = get_real_base_type(left_type);
 325         if (!left_type)
 326                 return 0;
 327         if (left_type->type != SYM_STRUCT &&
 328             left_type->type != SYM_UNION)
 329                 return 0;
 330
 331         /*
 332          * Ignore struct to struct assignments because for those we look at the
 333          * individual members.
 334          */
 335         right = strip_expr(expr->right);
 336         right_type = get_type(right);
 337         if (!right_type || right_type->type != SYM_PTR)
 338                 return 0;
 339
 340         /* If we are assigning struct members then normally that is handled
 341          * by fake assignments, however if we cast one struct to a different
 342          * of struct then we handle that here.
 343          */
 344         right_type = get_real_base_type(right_type);
 345         if (right_type == left_type)
 346                 return 0;
 347
 348         if (!points_to_user_data(right) && !is_skb_data(right))
 349                 return 0;
 350
 351         tag_as_user_data(expr->left);
 352         return 1;
 353 }
 354
 355 static int handle_get_user(struct expression *expr)
 356 {
 357         char *name;
 358         int ret = 0;
 359
 360         name = get_macro_name(expr->pos);
 361         if (!name || strcmp(name, "get_user") != 0)
 362                 return 0;
 363
 364         name = expr_to_var(expr->right);
 365         if (!name || strcmp(name, "__val_gu") != 0)
 366                 goto free;
 367         set_state_expr(my_id, expr->left, alloc_estate_whole(get_type(expr->left)));
 368         ret = 1;
 369 free:
 370         free_string(name);
 371         return ret;
 372 }
 373
 374 static void match_assign(struct expression *expr)
 375 {
 376         struct range_list *rl;
 377
 378         if (is_fake_call(expr->right))
 379                 return;
 380         if (handle_get_user(expr))
 381                 return;
 382         if (points_to_user_data(expr->right))
 383                 set_points_to_user_data(expr->left);
 384         if (handle_struct_assignment(expr))
 385                 return;
 386
 387         if (!get_user_rl(expr->right, &rl))
 388                 goto clear_old_state;
 389
 390         rl = cast_rl(get_type(expr->left), rl);
 391         set_state_expr(my_id, expr->left, alloc_estate_rl(rl));
 392
 393         return;
 394
 395 clear_old_state:
 396         if (get_state_expr(my_id, expr->left))
 397                 set_state_expr(my_id, expr->left, alloc_estate_empty());
 398 }
 399
 400 static void handle_eq_noteq(struct expression *expr)
 401 {
 402         struct smatch_state *left_orig, *right_orig;
 403
 404         left_orig = get_state_expr(my_id, expr->left);
 405         right_orig = get_state_expr(my_id, expr->right);
 406
 407         if (!left_orig && !right_orig)
 408                 return;
 409         if (left_orig && right_orig)
 410                 return;
 411
 412         if (left_orig) {
 413                 set_true_false_states_expr(my_id, expr->left,
 414                                 expr->op == SPECIAL_EQUAL ? alloc_estate_empty() : NULL,
 415                                 expr->op == SPECIAL_EQUAL ? NULL : alloc_estate_empty());
 416         } else {
 417                 set_true_false_states_expr(my_id, expr->right,
 418                                 expr->op == SPECIAL_EQUAL ? alloc_estate_empty() : NULL,
 419                                 expr->op == SPECIAL_EQUAL ? NULL : alloc_estate_empty());
 420         }
 421 }
 422
 423 static void handle_unsigned_lt_gt(struct expression *expr)
 424 {
 425         struct symbol *type;
 426         struct range_list *left;
 427         struct range_list *right;
 428         struct range_list *non_negative;
 429         sval_t min, minus_one;
 430
 431         /*
 432          * conditions are mostly handled by smatch_extra.c.  The special case
 433          * here is that say you have if (user_int < unknown_u32) {
 434          * In Smatch extra we say that, We have no idea what value
 435          * unknown_u32 is so the only thin we can say for sure is that
 436          * user_int is not -1 (UINT_MAX).  But in check_user_data2.c we should
 437          * assume that unless unknown_u32 is user data, it's probably less than
 438          * INT_MAX.
 439          *
 440          */
 441
 442         type = get_type(expr);
 443         if (!type_unsigned(type))
 444                 return;
 445
 446         /*
 447          * Assume if (user < trusted) { ... because I am lazy and because this
 448          * is the correct way to write code.
 449          */
 450         if (!get_user_rl(expr->left, &left))
 451                 return;
 452         if (get_user_rl(expr->right, &right))
 453                 return;
 454
 455         if (!sval_is_negative(rl_min(left)))
 456                 return;
 457         min = rl_min(left);
 458         minus_one.type = rl_type(left);
 459         minus_one.value = -1;
 460         non_negative = remove_range(left, min, minus_one);
 461
 462         switch (expr->op) {
 463         case '<':
 464         case SPECIAL_UNSIGNED_LT:
 465         case SPECIAL_LTE:
 466         case SPECIAL_UNSIGNED_LTE:
 467                 set_true_false_states_expr(my_id, expr->left,
 468                                            alloc_estate_rl(non_negative), NULL);
 469                 break;
 470         case '>':
 471         case SPECIAL_UNSIGNED_GT:
 472         case SPECIAL_GTE:
 473         case SPECIAL_UNSIGNED_GTE:
 474                 set_true_false_states_expr(my_id, expr->left,
 475                                            NULL, alloc_estate_rl(non_negative));
 476                 break;
 477         }
 478 }
 479
 480 static void match_condition(struct expression *expr)
 481 {
 482         if (expr->type != EXPR_COMPARE)
 483                 return;
 484
 485         if (expr->op == SPECIAL_EQUAL ||
 486             expr->op == SPECIAL_NOTEQUAL) {
 487                 handle_eq_noteq(expr);
 488                 return;
 489         }
 490
 491         handle_unsigned_lt_gt(expr);
 492 }
 493
 494 static void match_user_assign_function(const char *fn, struct expression *expr, void *unused)
 495 {
 496         func_gets_user_data = true;
 497
 498         tag_as_user_data(expr->left);
 499         set_points_to_user_data(expr->left);
 500 }
 501
 502 static void match_simple_strtoul(const char *fn, struct expression *expr, void *unused)
 503 {
 504         func_gets_user_data = true;
 505
 506         set_state_expr(my_id, expr->left, alloc_estate_whole(get_type(expr->left)));
 507 }
 508
 509 static int get_user_macro_rl(struct expression *expr, struct range_list **rl)
 510 {
 511         char *macro;
 512
 513         if (!expr)
 514                 return 0;
 515         macro = get_macro_name(expr->pos);
 516
 517         if (!macro)
 518                 return 0;
 519
 520         if (strcmp(macro, "ntohl") == 0) {
 521                 *rl = alloc_whole_rl(&uint_ctype);
 522                 return 1;
 523         }
 524         if (strcmp(macro, "ntohs") == 0) {
 525                 *rl = alloc_whole_rl(&ushort_ctype);
 526                 return 1;
 527         }
 528         return 0;
 529 }
 530
 531 struct db_info {
 532         struct range_list *rl;
 533         struct expression *call;
 534 };
 535 static int returned_rl_callback(void *_info, int argc, char **argv, char **azColName)
 536 {
 537         struct db_info *db_info = _info;
 538         struct range_list *rl;
 539         char *return_ranges = argv[0];
 540         char *user_ranges = argv[1];
 541         struct expression *arg;
 542         int comparison;
 543
 544         if (argc != 2)
 545                 return 0;
 546
 547         call_results_to_rl(db_info->call, get_type(db_info->call), user_ranges, &rl);
 548         if (str_to_comparison_arg(return_ranges, db_info->call, &comparison, &arg) &&
 549             comparison == SPECIAL_EQUAL) {
 550                 struct range_list *orig_rl;
 551
 552                 if (!get_user_rl(arg, &orig_rl))
 553                         return 0;
 554                 rl = rl_intersection(rl, orig_rl);
 555                 if (!rl)
 556                         return 0;
 557         }
 558         db_info->rl = rl_union(db_info->rl, rl);
 559
 560         return 0;
 561 }
 562
 563 static int has_user_data(struct symbol *sym)
 564 {
 565         struct sm_state *tmp;
 566
 567         FOR_EACH_MY_SM(my_id, __get_cur_stree(), tmp) {
 568                 if (tmp->sym == sym)
 569                         return 1;
 570         } END_FOR_EACH_SM(tmp);
 571         return 0;
 572 }
 573
 574 static int we_pass_user_data(struct expression *call)
 575 {
 576         struct expression *arg;
 577         struct symbol *sym;
 578
 579         FOR_EACH_PTR(call->args, arg) {
 580                 sym = expr_to_sym(arg);
 581                 if (!sym)
 582                         continue;
 583                 if (has_user_data(sym))
 584                         return 1;
 585         } END_FOR_EACH_PTR(arg);
 586
 587         return 0;
 588 }
 589
 590 static int db_returned_user_rl(struct expression *call, struct range_list **rl)
 591 {
 592         struct db_info db_info = {};
 593
 594         /* for function pointers assume everything is used */
 595         if (call->fn->type != EXPR_SYMBOL)
 596                 return 0;
 597         if (is_fake_call(call))
 598                 return 0;
 599
 600         db_info.call = call;
 601         run_sql(&returned_rl_callback, &db_info,
 602                 "select return, value from return_states where %s and type = %d and parameter = -1 and key = '$';",
 603                 get_static_filter(call->fn->symbol), USER_DATA3_SET);
 604         if (db_info.rl) {
 605                 func_gets_user_data = true;
 606                 *rl = db_info.rl;
 607                 return 1;
 608         }
 609
 610         run_sql(&returned_rl_callback, &db_info,
 611                 "select return, value from return_states where %s and type = %d and parameter = -1 and key = '$';",
 612                 get_static_filter(call->fn->symbol), USER_DATA3);
 613         if (db_info.rl) {
 614                 if (!we_pass_user_data(call))
 615                         return 0;
 616                 *rl = db_info.rl;
 617                 return 1;
 618         }
 619
 620         return 0;
 621 }
 622
 623 static int user_data_flag;
 624 static struct range_list *var_user_rl(struct expression *expr)
 625 {
 626         struct smatch_state *state;
 627         struct range_list *rl;
 628         struct range_list *absolute_rl;
 629
 630         if (expr->type == EXPR_BINOP && expr->op == '%') {
 631                 struct range_list *left, *right;
 632
 633                 if (!get_user_rl(expr->right, &right))
 634                         return NULL;
 635                 get_absolute_rl(expr->left, &left);
 636                 rl = rl_binop(left, '%', right);
 637                 goto found;
 638         }
 639
 640         if (get_user_macro_rl(expr, &rl))
 641                 goto found;
 642
 643         if (comes_from_skb_data(expr)) {
 644                 rl = alloc_whole_rl(get_type(expr));
 645                 goto found;
 646         }
 647
 648         state = get_state_expr(my_id, expr);
 649         if (state && estate_rl(state)) {
 650                 rl = estate_rl(state);
 651                 goto found;
 652         }
 653
 654         if (expr->type == EXPR_CALL && db_returned_user_rl(expr, &rl))
 655                 goto found;
 656
 657         return NULL;
 658 found:
 659         user_data_flag = 1;
 660         absolute_rl = var_to_absolute_rl(expr);
 661         return clone_rl(rl_intersection(rl, absolute_rl));
 662 }
 663
 664 int get_user_rl(struct expression *expr, struct range_list **rl)
 665 {
 666
 667         user_data_flag = 0;
 668         custom_get_absolute_rl(expr, &var_user_rl, rl);
 669         if (!user_data_flag) {
 670                 *rl = NULL;
 671                 return 0;
 672         }
 673         return 1;
 674 }
 675
 676 int get_user_rl_var_sym(const char *name, struct symbol *sym, struct range_list **rl)
 677 {
 678         struct smatch_state *state;
 679
 680         state = get_state(my_id, name, sym);
 681         if (state && estate_rl(state)) {
 682                 *rl = estate_rl(state);
 683                 return 1;
 684         }
 685         return 0;
 686 }
 687
 688 static void match_call_info(struct expression *expr)
 689 {
 690         struct range_list *rl;
 691         struct expression *arg;
 692         int i = 0;
 693
 694         i = -1;
 695         FOR_EACH_PTR(expr->args, arg) {
 696                 i++;
 697
 698                 if (!get_user_rl(arg, &rl))
 699                         continue;
 700
 701                 sql_insert_caller_info(expr, USER_DATA3, i, "$", show_rl(rl));
 702         } END_FOR_EACH_PTR(arg);
 703 }
 704
 705 static void struct_member_callback(struct expression *call, int param, char *printed_name, struct sm_state *sm)
 706 {
 707         struct smatch_state *state;
 708         struct range_list *rl;
 709
 710         if (strcmp(sm->state->name, "") == 0)
 711                 return;
 712
 713         state = get_state(SMATCH_EXTRA, sm->name, sm->sym);
 714         if (!state || !estate_rl(state))
 715                 rl = estate_rl(sm->state);
 716         else
 717                 rl = rl_intersection(estate_rl(sm->state), estate_rl(state));
 718
 719         sql_insert_caller_info(call, USER_DATA3, param, printed_name, show_rl(rl));
 720 }
 721
 722 static void set_param_user_data(const char *name, struct symbol *sym, char *key, char *value)
 723 {
 724         struct range_list *rl = NULL;
 725         struct smatch_state *state;
 726         struct symbol *type;
 727         char fullname[256];
 728
 729         if (strcmp(key, "*$") == 0)
 730                 snprintf(fullname, sizeof(fullname), "*%s", name);
 731         else if (strncmp(key, "$", 1) == 0)
 732                 snprintf(fullname, 256, "%s%s", name, key + 1);
 733         else
 734                 return;
 735
 736         type = get_member_type_from_key(symbol_expression(sym), key);
 737
 738         /* if the caller passes a void pointer with user data */
 739         if (strcmp(key, "*$") == 0 && type && type != &void_ctype) {
 740                 struct expression *expr = symbol_expression(sym);
 741
 742                 tag_as_user_data(expr);
 743                 set_points_to_user_data(expr);
 744                 return;
 745         }
 746         str_to_rl(type, value, &rl);
 747         state = alloc_estate_rl(rl);
 748         set_state(my_id, fullname, sym, state);
 749 }
 750
 751 static void set_called(const char *name, struct symbol *sym, char *key, char *value)
 752 {
 753         set_state(my_call_id, "this_function", NULL, &called);
 754 }
 755
 756 static void match_syscall_definition(struct symbol *sym)
 757 {
 758         struct symbol *arg;
 759         char *macro;
 760         char *name;
 761         int is_syscall = 0;
 762
 763         macro = get_macro_name(sym->pos);
 764         if (macro &&
 765             (strncmp("SYSCALL_DEFINE", macro, strlen("SYSCALL_DEFINE")) == 0 ||
 766              strncmp("COMPAT_SYSCALL_DEFINE", macro, strlen("COMPAT_SYSCALL_DEFINE")) == 0))
 767                 is_syscall = 1;
 768
 769         name = get_function();
 770         if (!option_no_db && get_state(my_call_id, "this_function", NULL) != &called) {
 771                 if (name && strncmp(name, "sys_", 4) == 0)
 772                         is_syscall = 1;
 773         }
 774
 775         if (name && strncmp(name, "compat_sys_", 11) == 0)
 776                 is_syscall = 1;
 777
 778         if (!is_syscall)
 779                 return;
 780
 781         FOR_EACH_PTR(sym->ctype.base_type->arguments, arg) {
 782                 set_state(my_id, arg->ident->name, arg, alloc_estate_whole(get_real_base_type(arg)));
 783         } END_FOR_EACH_PTR(arg);
 784 }
 785
 786 static void set_to_user_data(struct expression *expr, char *key, char *value)
 787 {
 788         char *name;
 789         struct symbol *sym;
 790         struct symbol *type;
 791         struct range_list *rl = NULL;
 792
 793         type = get_member_type_from_key(expr, key);
 794         name = get_variable_from_key(expr, key, &sym);
 795         if (!name || !sym)
 796                 goto free;
 797
 798         call_results_to_rl(expr, type, value, &rl);
 799
 800         set_state(my_id, name, sym, alloc_estate_rl(rl));
 801 free:
 802         free_string(name);
 803
 804 }
 805
 806 static void returns_param_user_data(struct expression *expr, int param, char *key, char *value)
 807 {
 808         struct expression *arg;
 809         struct expression *call;
 810
 811         call = expr;
 812         while (call->type == EXPR_ASSIGNMENT)
 813                 call = strip_expr(call->right);
 814         if (call->type != EXPR_CALL)
 815                 return;
 816
 817         if (!we_pass_user_data(call))
 818                 return;
 819
 820         if (param == -1) {
 821                 if (expr->type != EXPR_ASSIGNMENT)
 822                         return;
 823                 set_to_user_data(expr->left, key, value);
 824                 return;
 825         }
 826
 827         arg = get_argument_from_call_expr(call->args, param);
 828         if (!arg)
 829                 return;
 830         set_to_user_data(arg, key, value);
 831 }
 832
 833 static void returns_param_user_data_set(struct expression *expr, int param, char *key, char *value)
 834 {
 835         struct expression *arg;
 836
 837         func_gets_user_data = true;
 838
 839         if (param == -1) {
 840                 if (expr->type != EXPR_ASSIGNMENT)
 841                         return;
 842                 set_to_user_data(expr->left, key, value);
 843                 return;
 844         }
 845
 846         while (expr->type == EXPR_ASSIGNMENT)
 847                 expr = strip_expr(expr->right);
 848         if (expr->type != EXPR_CALL)
 849                 return;
 850
 851         arg = get_argument_from_call_expr(expr->args, param);
 852         if (!arg)
 853                 return;
 854         set_to_user_data(arg, key, value);
 855 }
 856
 857 static int has_empty_state(struct sm_state *sm)
 858 {
 859         struct sm_state *tmp;
 860
 861         FOR_EACH_PTR(sm->possible, tmp) {
 862                 if (!estate_rl(tmp->state))
 863                         return 1;
 864         } END_FOR_EACH_PTR(tmp);
 865
 866         return 0;
 867 }
 868
 869 static void param_set_to_user_data(int return_id, char *return_ranges, struct expression *expr)
 870 {
 871         struct sm_state *sm;
 872         struct smatch_state *start_state;
 873         struct range_list *rl;
 874         int param;
 875         const char *param_name;
 876
 877         FOR_EACH_MY_SM(my_id, __get_cur_stree(), sm) {
 878                 if (has_empty_state(sm))
 879                         continue;
 880
 881                 param = get_param_num_from_sym(sm->sym);
 882                 if (param < 0) {
 883                         if (expr_to_sym(expr) == sm->sym)
 884                                 param = -1;
 885                         else
 886                                 continue;
 887                 }
 888
 889                 /* The logic here was that if we were passed in a user data then
 890                  * we don't record that.  It's like the difference between
 891                  * param_filter and param_set.  When I think about it, I'm not
 892                  * sure it actually works.  It's probably harmless because we
 893                  * checked earlier that we're not returning a parameter...
 894                  * Let's mark this as a TODO.
 895                  */
 896                 start_state = get_state_stree(start_states, my_id, sm->name, sm->sym);
 897                 if (start_state && rl_equiv(estate_rl(sm->state), estate_rl(start_state)))
 898                         continue;
 899
 900                 param_name = get_param_name(sm);
 901                 if (!param_name)
 902                         continue;
 903                 if (strcmp(param_name, "$") == 0)
 904                         continue;
 905
 906                 sql_insert_return_states(return_id, return_ranges,
 907                                          func_gets_user_data ? USER_DATA3_SET : USER_DATA3,
 908                                          param, param_name, show_rl(estate_rl(sm->state)));
 909         } END_FOR_EACH_SM(sm);
 910
 911         if (get_user_rl(expr, &rl)) {
 912                 sql_insert_return_states(return_id, return_ranges,
 913                                          func_gets_user_data ? USER_DATA3_SET : USER_DATA3,
 914                                          -1, "$", show_rl(rl));
 915         }
 916 }
 917
 918 static struct int_stack *gets_data_stack;
 919 static void match_function_def(struct symbol *sym)
 920 {
 921         func_gets_user_data = false;
 922 }
 923
 924 static void match_inline_start(struct expression *expr)
 925 {
 926         push_int(&gets_data_stack, func_gets_user_data);
 927 }
 928
 929 static void match_inline_end(struct expression *expr)
 930 {
 931         func_gets_user_data = pop_int(&gets_data_stack);
 932 }
 933
 934 void check_user_data2(int id)
 935 {
 936         int i;
 937
 938         my_id = id;
 939
 940         if (option_project != PROJ_KERNEL)
 941                 return;
 942
 943         add_hook(&match_function_def, FUNC_DEF_HOOK);
 944         add_hook(&match_inline_start, INLINE_FN_START);
 945         add_hook(&match_inline_end, INLINE_FN_END);
 946
 947         add_hook(&save_start_states, AFTER_DEF_HOOK);
 948         add_hook(&free_start_states, AFTER_FUNC_HOOK);
 949         add_hook(&match_save_states, INLINE_FN_START);
 950         add_hook(&match_restore_states, INLINE_FN_END);
 951
 952         add_unmatched_state_hook(my_id, &empty_state);
 953         add_pre_merge_hook(my_id, &pre_merge_hook);
 954         add_merge_hook(my_id, &merge_estates);
 955
 956         add_function_hook("copy_from_user", &match_user_copy, INT_PTR(0));
 957         add_function_hook("__copy_from_user", &match_user_copy, INT_PTR(0));
 958         add_function_hook("memcpy_fromiovec", &match_user_copy, INT_PTR(0));
 959         for (i = 0; i < ARRAY_SIZE(kstr_funcs); i++)
 960                 add_function_hook(kstr_funcs[i], &match_user_copy, INT_PTR(2));
 961
 962         add_function_assign_hook("simple_strtol", &match_simple_strtoul, NULL);
 963         add_function_assign_hook("simple_strtoll", &match_simple_strtoul, NULL);
 964         add_function_assign_hook("simple_strtoul", &match_simple_strtoul, NULL);
 965         add_function_assign_hook("simple_strtoull", &match_simple_strtoul, NULL);
 966
 967         add_function_hook("sscanf", &match_sscanf, NULL);
 968
 969         add_function_assign_hook("memdup_user", &match_user_assign_function, NULL);
 970         add_function_assign_hook("kmap_atomic", &match_user_assign_function, NULL);
 971         add_function_assign_hook("skb_network_header", &match_user_assign_function, NULL);
 972
 973         add_hook(&match_syscall_definition, AFTER_DEF_HOOK);
 974
 975         add_hook(&match_assign, ASSIGNMENT_HOOK);
 976         add_hook(&match_condition, CONDITION_HOOK);
 977
 978         add_hook(&match_call_info, FUNCTION_CALL_HOOK);
 979         add_member_info_callback(my_id, struct_member_callback);
 980         select_caller_info_hook(set_param_user_data, USER_DATA3);
 981         select_return_states_hook(USER_DATA3, &returns_param_user_data);
 982         select_return_states_hook(USER_DATA3_SET, &returns_param_user_data_set);
 983         add_split_return_callback(&param_set_to_user_data);
 984 }
 985
 986 void check_user_data3(int id)
 987 {
 988         my_call_id = id;
 989
 990         if (option_project != PROJ_KERNEL)
 991                 return;
 992         select_caller_info_hook(set_called, INTERNAL);
 993 }
 994