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