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         if (expr->type == EXPR_BINOP && expr->op == '+')
 270                 return is_skb_data(expr->left);
 271
 272         expr = strip_expr(expr);
 273         if (!expr)
 274                 return 0;
 275         if (expr->type != EXPR_DEREF || expr->op != '.')
 276                 return 0;
 277
 278         if (!expr->member)
 279                 return 0;
 280         if (strcmp(expr->member->name, "data") != 0)
 281                 return 0;
 282
 283         sym = expr_to_sym(expr->deref);
 284         if (!sym)
 285                 return 0;
 286         sym = get_real_base_type(sym);
 287         if (!sym || sym->type != SYM_PTR)
 288                 return 0;
 289         sym = get_real_base_type(sym);
 290         if (!sym || sym->type != SYM_STRUCT || !sym->ident)
 291                 return 0;
 292         if (strcmp(sym->ident->name, "sk_buff") != 0)
 293                 return 0;
 294
 295         return 1;
 296 }
 297
 298 static int comes_from_skb_data(struct expression *expr)
 299 {
 300         expr = strip_expr(expr);
 301         if (!expr || expr->type != EXPR_PREOP || expr->op != '*')
 302                 return 0;
 303
 304         expr = strip_expr(expr->unop);
 305         if (expr->type == EXPR_BINOP && expr->op == '+')
 306                 expr = strip_expr(expr->left);
 307
 308         return is_skb_data(expr);
 309 }
 310
 311 static int handle_struct_assignment(struct expression *expr)
 312 {
 313         struct expression *right;
 314         struct symbol *left_type, *right_type;
 315
 316         left_type = get_type(expr->left);
 317         if (!left_type || left_type->type != SYM_PTR)
 318                 return 0;
 319         left_type = get_real_base_type(left_type);
 320         if (!left_type || left_type->type != SYM_STRUCT)
 321                 return 0;
 322
 323         /*
 324          * Ignore struct to struct assignments because for those we look at the
 325          * individual members.
 326          */
 327         right = strip_expr(expr->right);
 328         right_type = get_type(right);
 329         if (!right_type || right_type->type != SYM_PTR)
 330                 return 0;
 331
 332         /* If we are assigning struct members then normally that is handled
 333          * by fake assignments, however if we cast one struct to a different
 334          * of struct then we handle that here.
 335          */
 336         right_type = get_real_base_type(right_type);
 337         if (right_type == left_type)
 338                 return 0;
 339
 340         if (!points_to_user_data(right) && !is_skb_data(right))
 341                 return 0;
 342
 343         tag_as_user_data(expr->left);
 344         return 1;
 345 }
 346
 347 static int handle_get_user(struct expression *expr)
 348 {
 349         char *name;
 350         int ret = 0;
 351
 352         name = get_macro_name(expr->pos);
 353         if (!name || strcmp(name, "get_user") != 0)
 354                 return 0;
 355
 356         name = expr_to_var(expr->right);
 357         if (!name || strcmp(name, "__val_gu") != 0)
 358                 goto free;
 359         set_state_expr(my_id, expr->left, alloc_estate_whole(get_type(expr->left)));
 360         ret = 1;
 361 free:
 362         free_string(name);
 363         return ret;
 364 }
 365
 366 static void match_assign(struct expression *expr)
 367 {
 368         struct range_list *rl;
 369
 370         if (is_fake_call(expr->right))
 371                 return;
 372         if (handle_get_user(expr))
 373                 return;
 374         if (points_to_user_data(expr->right))
 375                 set_points_to_user_data(expr->left);
 376         if (handle_struct_assignment(expr))
 377                 return;
 378
 379         if (!get_user_rl(expr->right, &rl))
 380                 goto clear_old_state;
 381
 382         rl = cast_rl(get_type(expr->left), rl);
 383         set_state_expr(my_id, expr->left, alloc_estate_rl(rl));
 384
 385         return;
 386
 387 clear_old_state:
 388         if (get_state_expr(my_id, expr->left))
 389                 set_state_expr(my_id, expr->left, alloc_estate_empty());
 390 }
 391
 392 static void match_condition(struct expression *expr)
 393 {
 394         struct smatch_state *left_orig = NULL;
 395         struct smatch_state *right_orig = NULL;
 396
 397         if (expr->type != EXPR_COMPARE || expr->op != SPECIAL_EQUAL)
 398                 return;
 399
 400         left_orig = get_state_expr(my_id, expr->left);
 401         right_orig = get_state_expr(my_id, expr->right);
 402
 403         if (!left_orig && !right_orig)
 404                 return;
 405         if (left_orig && right_orig)
 406                 return;
 407
 408         if (left_orig)
 409                 set_true_false_states_expr(my_id, expr->left, alloc_estate_empty(), NULL);
 410         else
 411                 set_true_false_states_expr(my_id, expr->right, alloc_estate_empty(), NULL);
 412 }
 413
 414 static void match_user_assign_function(const char *fn, struct expression *expr, void *unused)
 415 {
 416         func_gets_user_data = true;
 417
 418         tag_as_user_data(expr->left);
 419         set_points_to_user_data(expr->left);
 420 }
 421
 422 static void match_simple_strtoul(const char *fn, struct expression *expr, void *unused)
 423 {
 424         func_gets_user_data = true;
 425
 426         set_state_expr(my_id, expr->left, alloc_estate_whole(get_type(expr->left)));
 427 }
 428
 429 static int get_user_macro_rl(struct expression *expr, struct range_list **rl)
 430 {
 431         char *macro;
 432
 433         if (!expr)
 434                 return 0;
 435         macro = get_macro_name(expr->pos);
 436
 437         if (!macro)
 438                 return 0;
 439
 440         if (strcmp(macro, "ntohl") == 0) {
 441                 *rl = alloc_whole_rl(&uint_ctype);
 442                 return 1;
 443         }
 444         if (strcmp(macro, "ntohs") == 0) {
 445                 *rl = alloc_whole_rl(&ushort_ctype);
 446                 return 1;
 447         }
 448         return 0;
 449 }
 450
 451 struct db_info {
 452         struct range_list *rl;
 453         struct expression *call;
 454 };
 455 static int returned_rl_callback(void *_info, int argc, char **argv, char **azColName)
 456 {
 457         struct db_info *db_info = _info;
 458         struct range_list *rl;
 459         char *return_ranges = argv[0];
 460         char *user_ranges = argv[1];
 461         struct expression *arg;
 462         int comparison;
 463
 464         if (argc != 2)
 465                 return 0;
 466
 467         call_results_to_rl(db_info->call, get_type(db_info->call), user_ranges, &rl);
 468         if (str_to_comparison_arg(return_ranges, db_info->call, &comparison, &arg) &&
 469             comparison == SPECIAL_EQUAL) {
 470                 struct range_list *orig_rl;
 471
 472                 if (!get_user_rl(arg, &orig_rl))
 473                         return 0;
 474                 rl = rl_intersection(rl, orig_rl);
 475                 if (!rl)
 476                         return 0;
 477         }
 478         db_info->rl = rl_union(db_info->rl, rl);
 479
 480         return 0;
 481 }
 482
 483 static int has_user_data(struct symbol *sym)
 484 {
 485         struct sm_state *tmp;
 486
 487         FOR_EACH_MY_SM(my_id, __get_cur_stree(), tmp) {
 488                 if (tmp->sym == sym)
 489                         return 1;
 490         } END_FOR_EACH_SM(tmp);
 491         return 0;
 492 }
 493
 494 static int we_pass_user_data(struct expression *call)
 495 {
 496         struct expression *arg;
 497         struct symbol *sym;
 498
 499         FOR_EACH_PTR(call->args, arg) {
 500                 sym = expr_to_sym(arg);
 501                 if (!sym)
 502                         continue;
 503                 if (has_user_data(sym))
 504                         return 1;
 505         } END_FOR_EACH_PTR(arg);
 506
 507         return 0;
 508 }
 509
 510 static int db_returned_user_rl(struct expression *call, struct range_list **rl)
 511 {
 512         struct db_info db_info = {};
 513
 514         /* for function pointers assume everything is used */
 515         if (call->fn->type != EXPR_SYMBOL)
 516                 return 0;
 517         if (is_fake_call(call))
 518                 return 0;
 519
 520         db_info.call = call;
 521         run_sql(&returned_rl_callback, &db_info,
 522                 "select return, value from return_states where %s and type = %d and parameter = -1 and key = '$';",
 523                 get_static_filter(call->fn->symbol), USER_DATA3_SET);
 524         if (db_info.rl) {
 525                 func_gets_user_data = true;
 526                 *rl = db_info.rl;
 527                 return 1;
 528         }
 529
 530         run_sql(&returned_rl_callback, &db_info,
 531                 "select return, value from return_states where %s and type = %d and parameter = -1 and key = '$';",
 532                 get_static_filter(call->fn->symbol), USER_DATA3);
 533         if (db_info.rl) {
 534                 if (!we_pass_user_data(call))
 535                         return 0;
 536                 *rl = db_info.rl;
 537                 return 1;
 538         }
 539
 540         return 0;
 541 }
 542
 543 static int user_data_flag;
 544 static struct range_list *var_user_rl(struct expression *expr)
 545 {
 546         struct smatch_state *state;
 547         struct range_list *rl;
 548         struct range_list *absolute_rl;
 549
 550         if (get_user_macro_rl(expr, &rl))
 551                 goto found;
 552
 553         if (comes_from_skb_data(expr)) {
 554                 rl = alloc_whole_rl(get_type(expr));
 555                 goto found;
 556         }
 557
 558         state = get_state_expr(my_id, expr);
 559         if (state && estate_rl(state)) {
 560                 rl = estate_rl(state);
 561                 goto found;
 562         }
 563
 564         if (expr->type == EXPR_CALL && db_returned_user_rl(expr, &rl))
 565                 goto found;
 566
 567         return NULL;
 568 found:
 569         user_data_flag = 1;
 570         absolute_rl = var_to_absolute_rl(expr);
 571         return clone_rl(rl_intersection(rl, absolute_rl));
 572 }
 573
 574 int get_user_rl(struct expression *expr, struct range_list **rl)
 575 {
 576
 577         user_data_flag = 0;
 578         custom_get_absolute_rl(expr, &var_user_rl, rl);
 579         if (!user_data_flag) {
 580                 *rl = NULL;
 581                 return 0;
 582         }
 583         return 1;
 584 }
 585
 586 int get_user_rl_var_sym(const char *name, struct symbol *sym, struct range_list **rl)
 587 {
 588         struct smatch_state *state;
 589
 590         state = get_state(my_id, name, sym);
 591         if (state && estate_rl(state)) {
 592                 *rl = estate_rl(state);
 593                 return 1;
 594         }
 595         return 0;
 596 }
 597
 598 static void match_call_info(struct expression *expr)
 599 {
 600         struct range_list *rl;
 601         struct expression *arg;
 602         int i = 0;
 603
 604         i = -1;
 605         FOR_EACH_PTR(expr->args, arg) {
 606                 i++;
 607
 608                 if (!get_user_rl(arg, &rl))
 609                         continue;
 610
 611                 sql_insert_caller_info(expr, USER_DATA3, i, "$", show_rl(rl));
 612         } END_FOR_EACH_PTR(arg);
 613 }
 614
 615 static void struct_member_callback(struct expression *call, int param, char *printed_name, struct sm_state *sm)
 616 {
 617         struct smatch_state *state;
 618         struct range_list *rl;
 619
 620         if (strcmp(sm->state->name, "") == 0)
 621                 return;
 622
 623         state = get_state(SMATCH_EXTRA, sm->name, sm->sym);
 624         if (!state || !estate_rl(state))
 625                 rl = estate_rl(sm->state);
 626         else
 627                 rl = rl_intersection(estate_rl(sm->state), estate_rl(state));
 628
 629         sql_insert_caller_info(call, USER_DATA3, param, printed_name, show_rl(rl));
 630 }
 631
 632 static void set_param_user_data(const char *name, struct symbol *sym, char *key, char *value)
 633 {
 634         struct range_list *rl = NULL;
 635         struct smatch_state *state;
 636         struct symbol *type;
 637         char fullname[256];
 638
 639         if (strcmp(key, "*$") == 0)
 640                 snprintf(fullname, sizeof(fullname), "*%s", name);
 641         else if (strncmp(key, "$", 1) == 0)
 642                 snprintf(fullname, 256, "%s%s", name, key + 1);
 643         else
 644                 return;
 645
 646         type = get_member_type_from_key(symbol_expression(sym), key);
 647
 648         /* if the caller passes a void pointer with user data */
 649         if (strcmp(key, "*$") == 0 && type && type != &void_ctype) {
 650                 struct expression *expr = symbol_expression(sym);
 651
 652                 tag_as_user_data(expr);
 653                 set_points_to_user_data(expr);
 654                 return;
 655         }
 656         str_to_rl(type, value, &rl);
 657         state = alloc_estate_rl(rl);
 658         set_state(my_id, fullname, sym, state);
 659 }
 660
 661 static void set_called(const char *name, struct symbol *sym, char *key, char *value)
 662 {
 663         set_state(my_call_id, "this_function", NULL, &called);
 664 }
 665
 666 static void match_syscall_definition(struct symbol *sym)
 667 {
 668         struct symbol *arg;
 669         char *macro;
 670         char *name;
 671         int is_syscall = 0;
 672
 673         macro = get_macro_name(sym->pos);
 674         if (macro &&
 675             (strncmp("SYSCALL_DEFINE", macro, strlen("SYSCALL_DEFINE")) == 0 ||
 676              strncmp("COMPAT_SYSCALL_DEFINE", macro, strlen("COMPAT_SYSCALL_DEFINE")) == 0))
 677                 is_syscall = 1;
 678
 679         name = get_function();
 680         if (!option_no_db && get_state(my_call_id, "this_function", NULL) != &called) {
 681                 if (name && strncmp(name, "sys_", 4) == 0)
 682                         is_syscall = 1;
 683         }
 684
 685         if (name && strncmp(name, "compat_sys_", 11) == 0)
 686                 is_syscall = 1;
 687
 688         if (!is_syscall)
 689                 return;
 690
 691         FOR_EACH_PTR(sym->ctype.base_type->arguments, arg) {
 692                 set_state(my_id, arg->ident->name, arg, alloc_estate_whole(get_real_base_type(arg)));
 693         } END_FOR_EACH_PTR(arg);
 694 }
 695
 696 static void set_to_user_data(struct expression *expr, char *key, char *value)
 697 {
 698         char *name;
 699         struct symbol *sym;
 700         struct symbol *type;
 701         struct range_list *rl = NULL;
 702
 703         type = get_member_type_from_key(expr, key);
 704         name = get_variable_from_key(expr, key, &sym);
 705         if (!name || !sym)
 706                 goto free;
 707
 708         call_results_to_rl(expr, type, value, &rl);
 709
 710         set_state(my_id, name, sym, alloc_estate_rl(rl));
 711 free:
 712         free_string(name);
 713
 714 }
 715
 716 static void returns_param_user_data(struct expression *expr, int param, char *key, char *value)
 717 {
 718         struct expression *arg;
 719         struct expression *call;
 720
 721         call = expr;
 722         while (call->type == EXPR_ASSIGNMENT)
 723                 call = strip_expr(call->right);
 724         if (call->type != EXPR_CALL)
 725                 return;
 726
 727         if (!we_pass_user_data(call))
 728                 return;
 729
 730         if (param == -1) {
 731                 if (expr->type != EXPR_ASSIGNMENT)
 732                         return;
 733                 set_to_user_data(expr->left, key, value);
 734                 return;
 735         }
 736
 737         arg = get_argument_from_call_expr(call->args, param);
 738         if (!arg)
 739                 return;
 740         set_to_user_data(arg, key, value);
 741 }
 742
 743 static void returns_param_user_data_set(struct expression *expr, int param, char *key, char *value)
 744 {
 745         struct expression *arg;
 746
 747         func_gets_user_data = true;
 748
 749         if (param == -1) {
 750                 if (expr->type != EXPR_ASSIGNMENT)
 751                         return;
 752                 set_to_user_data(expr->left, key, value);
 753                 return;
 754         }
 755
 756         while (expr->type == EXPR_ASSIGNMENT)
 757                 expr = strip_expr(expr->right);
 758         if (expr->type != EXPR_CALL)
 759                 return;
 760
 761         arg = get_argument_from_call_expr(expr->args, param);
 762         if (!arg)
 763                 return;
 764         set_to_user_data(arg, key, value);
 765 }
 766
 767 static int has_empty_state(struct sm_state *sm)
 768 {
 769         struct sm_state *tmp;
 770
 771         FOR_EACH_PTR(sm->possible, tmp) {
 772                 if (!estate_rl(tmp->state))
 773                         return 1;
 774         } END_FOR_EACH_PTR(tmp);
 775
 776         return 0;
 777 }
 778
 779 static void param_set_to_user_data(int return_id, char *return_ranges, struct expression *expr)
 780 {
 781         struct sm_state *sm;
 782         struct smatch_state *start_state;
 783         struct range_list *rl;
 784         int param;
 785         const char *param_name;
 786
 787         FOR_EACH_MY_SM(my_id, __get_cur_stree(), sm) {
 788                 if (has_empty_state(sm))
 789                         continue;
 790
 791                 param = get_param_num_from_sym(sm->sym);
 792                 if (param < 0) {
 793                         if (expr_to_sym(expr) == sm->sym)
 794                                 param = -1;
 795                         else
 796                                 continue;
 797                 }
 798
 799                 /* The logic here was that if we were passed in a user data then
 800                  * we don't record that.  It's like the difference between
 801                  * param_filter and param_set.  When I think about it, I'm not
 802                  * sure it actually works.  It's probably harmless because we
 803                  * checked earlier that we're not returning a parameter...
 804                  * Let's mark this as a TODO.
 805                  */
 806                 start_state = get_state_stree(start_states, my_id, sm->name, sm->sym);
 807                 if (start_state && rl_equiv(estate_rl(sm->state), estate_rl(start_state)))
 808                         continue;
 809
 810                 param_name = get_param_name(sm);
 811                 if (!param_name)
 812                         continue;
 813                 if (strcmp(param_name, "$") == 0)
 814                         continue;
 815
 816                 sql_insert_return_states(return_id, return_ranges,
 817                                          func_gets_user_data ? USER_DATA3_SET : USER_DATA3,
 818                                          param, param_name, show_rl(estate_rl(sm->state)));
 819         } END_FOR_EACH_SM(sm);
 820
 821         if (get_user_rl(expr, &rl)) {
 822                 sql_insert_return_states(return_id, return_ranges,
 823                                          func_gets_user_data ? USER_DATA3_SET : USER_DATA3,
 824                                          -1, "$", show_rl(rl));
 825         }
 826 }
 827
 828 static struct int_stack *gets_data_stack;
 829 static void match_function_def(struct symbol *sym)
 830 {
 831         func_gets_user_data = false;
 832 }
 833
 834 static void match_inline_start(struct expression *expr)
 835 {
 836         push_int(&gets_data_stack, func_gets_user_data);
 837 }
 838
 839 static void match_inline_end(struct expression *expr)
 840 {
 841         func_gets_user_data = pop_int(&gets_data_stack);
 842 }
 843
 844 void check_user_data2(int id)
 845 {
 846         int i;
 847
 848         my_id = id;
 849
 850         if (option_project != PROJ_KERNEL)
 851                 return;
 852
 853         add_hook(&match_function_def, FUNC_DEF_HOOK);
 854         add_hook(&match_inline_start, INLINE_FN_START);
 855         add_hook(&match_inline_end, INLINE_FN_END);
 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