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->type == EXPR_BINOP && expr->op == '+')
 309                 expr = strip_expr(expr->left);
 310
 311         return is_skb_data(expr);
 312 }
 313
 314 static int handle_struct_assignment(struct expression *expr)
 315 {
 316         struct expression *right;
 317         struct symbol *left_type, *right_type;
 318
 319         left_type = get_type(expr->left);
 320         if (!left_type || left_type->type != SYM_PTR)
 321                 return 0;
 322         left_type = get_real_base_type(left_type);
 323         if (!left_type)
 324                 return 0;
 325         if (left_type->type != SYM_STRUCT &&
 326             left_type->type != SYM_UNION)
 327                 return 0;
 328
 329         /*
 330          * Ignore struct to struct assignments because for those we look at the
 331          * individual members.
 332          */
 333         right = strip_expr(expr->right);
 334         right_type = get_type(right);
 335         if (!right_type || right_type->type != SYM_PTR)
 336                 return 0;
 337
 338         /* If we are assigning struct members then normally that is handled
 339          * by fake assignments, however if we cast one struct to a different
 340          * of struct then we handle that here.
 341          */
 342         right_type = get_real_base_type(right_type);
 343         if (right_type == left_type)
 344                 return 0;
 345
 346         if (!points_to_user_data(right) && !is_skb_data(right))
 347                 return 0;
 348
 349         tag_as_user_data(expr->left);
 350         return 1;
 351 }
 352
 353 static int handle_get_user(struct expression *expr)
 354 {
 355         char *name;
 356         int ret = 0;
 357
 358         name = get_macro_name(expr->pos);
 359         if (!name || strcmp(name, "get_user") != 0)
 360                 return 0;
 361
 362         name = expr_to_var(expr->right);
 363         if (!name || strcmp(name, "__val_gu") != 0)
 364                 goto free;
 365         set_state_expr(my_id, expr->left, alloc_estate_whole(get_type(expr->left)));
 366         ret = 1;
 367 free:
 368         free_string(name);
 369         return ret;
 370 }
 371
 372 static void match_assign(struct expression *expr)
 373 {
 374         struct range_list *rl;
 375
 376         if (is_fake_call(expr->right))
 377                 return;
 378         if (handle_get_user(expr))
 379                 return;
 380         if (points_to_user_data(expr->right))
 381                 set_points_to_user_data(expr->left);
 382         if (handle_struct_assignment(expr))
 383                 return;
 384
 385         if (!get_user_rl(expr->right, &rl))
 386                 goto clear_old_state;
 387
 388         rl = cast_rl(get_type(expr->left), rl);
 389         set_state_expr(my_id, expr->left, alloc_estate_rl(rl));
 390
 391         return;
 392
 393 clear_old_state:
 394         if (get_state_expr(my_id, expr->left))
 395                 set_state_expr(my_id, expr->left, alloc_estate_empty());
 396 }
 397
 398 static void match_condition(struct expression *expr)
 399 {
 400         struct smatch_state *left_orig = NULL;
 401         struct smatch_state *right_orig = NULL;
 402
 403         if (expr->type != EXPR_COMPARE)
 404                 return;
 405         if (expr->op != SPECIAL_EQUAL &&
 406             expr->op != SPECIAL_NOTEQUAL)
 407                 return;
 408
 409         left_orig = get_state_expr(my_id, expr->left);
 410         right_orig = get_state_expr(my_id, expr->right);
 411
 412         if (!left_orig && !right_orig)
 413                 return;
 414         if (left_orig && right_orig)
 415                 return;
 416
 417         if (left_orig) {
 418                 set_true_false_states_expr(my_id, expr->left,
 419                                 expr->op == SPECIAL_EQUAL ? alloc_estate_empty() : NULL,
 420                                 expr->op == SPECIAL_EQUAL ? NULL : alloc_estate_empty());
 421         } else {
 422                 set_true_false_states_expr(my_id, expr->right,
 423                                 expr->op == SPECIAL_EQUAL ? alloc_estate_empty() : NULL,
 424                                 expr->op == SPECIAL_EQUAL ? NULL : alloc_estate_empty());
 425         }
 426 }
 427
 428 static void match_user_assign_function(const char *fn, struct expression *expr, void *unused)
 429 {
 430         func_gets_user_data = true;
 431
 432         tag_as_user_data(expr->left);
 433         set_points_to_user_data(expr->left);
 434 }
 435
 436 static void match_simple_strtoul(const char *fn, struct expression *expr, void *unused)
 437 {
 438         func_gets_user_data = true;
 439
 440         set_state_expr(my_id, expr->left, alloc_estate_whole(get_type(expr->left)));
 441 }
 442
 443 static int get_user_macro_rl(struct expression *expr, struct range_list **rl)
 444 {
 445         char *macro;
 446
 447         if (!expr)
 448                 return 0;
 449         macro = get_macro_name(expr->pos);
 450
 451         if (!macro)
 452                 return 0;
 453
 454         if (strcmp(macro, "ntohl") == 0) {
 455                 *rl = alloc_whole_rl(&uint_ctype);
 456                 return 1;
 457         }
 458         if (strcmp(macro, "ntohs") == 0) {
 459                 *rl = alloc_whole_rl(&ushort_ctype);
 460                 return 1;
 461         }
 462         return 0;
 463 }
 464
 465 struct db_info {
 466         struct range_list *rl;
 467         struct expression *call;
 468 };
 469 static int returned_rl_callback(void *_info, int argc, char **argv, char **azColName)
 470 {
 471         struct db_info *db_info = _info;
 472         struct range_list *rl;
 473         char *return_ranges = argv[0];
 474         char *user_ranges = argv[1];
 475         struct expression *arg;
 476         int comparison;
 477
 478         if (argc != 2)
 479                 return 0;
 480
 481         call_results_to_rl(db_info->call, get_type(db_info->call), user_ranges, &rl);
 482         if (str_to_comparison_arg(return_ranges, db_info->call, &comparison, &arg) &&
 483             comparison == SPECIAL_EQUAL) {
 484                 struct range_list *orig_rl;
 485
 486                 if (!get_user_rl(arg, &orig_rl))
 487                         return 0;
 488                 rl = rl_intersection(rl, orig_rl);
 489                 if (!rl)
 490                         return 0;
 491         }
 492         db_info->rl = rl_union(db_info->rl, rl);
 493
 494         return 0;
 495 }
 496
 497 static int has_user_data(struct symbol *sym)
 498 {
 499         struct sm_state *tmp;
 500
 501         FOR_EACH_MY_SM(my_id, __get_cur_stree(), tmp) {
 502                 if (tmp->sym == sym)
 503                         return 1;
 504         } END_FOR_EACH_SM(tmp);
 505         return 0;
 506 }
 507
 508 static int we_pass_user_data(struct expression *call)
 509 {
 510         struct expression *arg;
 511         struct symbol *sym;
 512
 513         FOR_EACH_PTR(call->args, arg) {
 514                 sym = expr_to_sym(arg);
 515                 if (!sym)
 516                         continue;
 517                 if (has_user_data(sym))
 518                         return 1;
 519         } END_FOR_EACH_PTR(arg);
 520
 521         return 0;
 522 }
 523
 524 static int db_returned_user_rl(struct expression *call, struct range_list **rl)
 525 {
 526         struct db_info db_info = {};
 527
 528         /* for function pointers assume everything is used */
 529         if (call->fn->type != EXPR_SYMBOL)
 530                 return 0;
 531         if (is_fake_call(call))
 532                 return 0;
 533
 534         db_info.call = call;
 535         run_sql(&returned_rl_callback, &db_info,
 536                 "select return, value from return_states where %s and type = %d and parameter = -1 and key = '$';",
 537                 get_static_filter(call->fn->symbol), USER_DATA3_SET);
 538         if (db_info.rl) {
 539                 func_gets_user_data = true;
 540                 *rl = db_info.rl;
 541                 return 1;
 542         }
 543
 544         run_sql(&returned_rl_callback, &db_info,
 545                 "select return, value from return_states where %s and type = %d and parameter = -1 and key = '$';",
 546                 get_static_filter(call->fn->symbol), USER_DATA3);
 547         if (db_info.rl) {
 548                 if (!we_pass_user_data(call))
 549                         return 0;
 550                 *rl = db_info.rl;
 551                 return 1;
 552         }
 553
 554         return 0;
 555 }
 556
 557 static int user_data_flag;
 558 static struct range_list *var_user_rl(struct expression *expr)
 559 {
 560         struct smatch_state *state;
 561         struct range_list *rl;
 562         struct range_list *absolute_rl;
 563
 564         if (get_user_macro_rl(expr, &rl))
 565                 goto found;
 566
 567         if (comes_from_skb_data(expr)) {
 568                 rl = alloc_whole_rl(get_type(expr));
 569                 goto found;
 570         }
 571
 572         state = get_state_expr(my_id, expr);
 573         if (state && estate_rl(state)) {
 574                 rl = estate_rl(state);
 575                 goto found;
 576         }
 577
 578         if (expr->type == EXPR_CALL && db_returned_user_rl(expr, &rl))
 579                 goto found;
 580
 581         return NULL;
 582 found:
 583         user_data_flag = 1;
 584         absolute_rl = var_to_absolute_rl(expr);
 585         return clone_rl(rl_intersection(rl, absolute_rl));
 586 }
 587
 588 int get_user_rl(struct expression *expr, struct range_list **rl)
 589 {
 590
 591         user_data_flag = 0;
 592         custom_get_absolute_rl(expr, &var_user_rl, rl);
 593         if (!user_data_flag) {
 594                 *rl = NULL;
 595                 return 0;
 596         }
 597         return 1;
 598 }
 599
 600 int get_user_rl_var_sym(const char *name, struct symbol *sym, struct range_list **rl)
 601 {
 602         struct smatch_state *state;
 603
 604         state = get_state(my_id, name, sym);
 605         if (state && estate_rl(state)) {
 606                 *rl = estate_rl(state);
 607                 return 1;
 608         }
 609         return 0;
 610 }
 611
 612 static void match_call_info(struct expression *expr)
 613 {
 614         struct range_list *rl;
 615         struct expression *arg;
 616         int i = 0;
 617
 618         i = -1;
 619         FOR_EACH_PTR(expr->args, arg) {
 620                 i++;
 621
 622                 if (!get_user_rl(arg, &rl))
 623                         continue;
 624
 625                 sql_insert_caller_info(expr, USER_DATA3, i, "$", show_rl(rl));
 626         } END_FOR_EACH_PTR(arg);
 627 }
 628
 629 static void struct_member_callback(struct expression *call, int param, char *printed_name, struct sm_state *sm)
 630 {
 631         struct smatch_state *state;
 632         struct range_list *rl;
 633
 634         if (strcmp(sm->state->name, "") == 0)
 635                 return;
 636
 637         state = get_state(SMATCH_EXTRA, sm->name, sm->sym);
 638         if (!state || !estate_rl(state))
 639                 rl = estate_rl(sm->state);
 640         else
 641                 rl = rl_intersection(estate_rl(sm->state), estate_rl(state));
 642
 643         sql_insert_caller_info(call, USER_DATA3, param, printed_name, show_rl(rl));
 644 }
 645
 646 static void set_param_user_data(const char *name, struct symbol *sym, char *key, char *value)
 647 {
 648         struct range_list *rl = NULL;
 649         struct smatch_state *state;
 650         struct symbol *type;
 651         char fullname[256];
 652
 653         if (strcmp(key, "*$") == 0)
 654                 snprintf(fullname, sizeof(fullname), "*%s", name);
 655         else if (strncmp(key, "$", 1) == 0)
 656                 snprintf(fullname, 256, "%s%s", name, key + 1);
 657         else
 658                 return;
 659
 660         type = get_member_type_from_key(symbol_expression(sym), key);
 661
 662         /* if the caller passes a void pointer with user data */
 663         if (strcmp(key, "*$") == 0 && type && type != &void_ctype) {
 664                 struct expression *expr = symbol_expression(sym);
 665
 666                 tag_as_user_data(expr);
 667                 set_points_to_user_data(expr);
 668                 return;
 669         }
 670         str_to_rl(type, value, &rl);
 671         state = alloc_estate_rl(rl);
 672         set_state(my_id, fullname, sym, state);
 673 }
 674
 675 static void set_called(const char *name, struct symbol *sym, char *key, char *value)
 676 {
 677         set_state(my_call_id, "this_function", NULL, &called);
 678 }
 679
 680 static void match_syscall_definition(struct symbol *sym)
 681 {
 682         struct symbol *arg;
 683         char *macro;
 684         char *name;
 685         int is_syscall = 0;
 686
 687         macro = get_macro_name(sym->pos);
 688         if (macro &&
 689             (strncmp("SYSCALL_DEFINE", macro, strlen("SYSCALL_DEFINE")) == 0 ||
 690              strncmp("COMPAT_SYSCALL_DEFINE", macro, strlen("COMPAT_SYSCALL_DEFINE")) == 0))
 691                 is_syscall = 1;
 692
 693         name = get_function();
 694         if (!option_no_db && get_state(my_call_id, "this_function", NULL) != &called) {
 695                 if (name && strncmp(name, "sys_", 4) == 0)
 696                         is_syscall = 1;
 697         }
 698
 699         if (name && strncmp(name, "compat_sys_", 11) == 0)
 700                 is_syscall = 1;
 701
 702         if (!is_syscall)
 703                 return;
 704
 705         FOR_EACH_PTR(sym->ctype.base_type->arguments, arg) {
 706                 set_state(my_id, arg->ident->name, arg, alloc_estate_whole(get_real_base_type(arg)));
 707         } END_FOR_EACH_PTR(arg);
 708 }
 709
 710 static void set_to_user_data(struct expression *expr, char *key, char *value)
 711 {
 712         char *name;
 713         struct symbol *sym;
 714         struct symbol *type;
 715         struct range_list *rl = NULL;
 716
 717         type = get_member_type_from_key(expr, key);
 718         name = get_variable_from_key(expr, key, &sym);
 719         if (!name || !sym)
 720                 goto free;
 721
 722         call_results_to_rl(expr, type, value, &rl);
 723
 724         set_state(my_id, name, sym, alloc_estate_rl(rl));
 725 free:
 726         free_string(name);
 727
 728 }
 729
 730 static void returns_param_user_data(struct expression *expr, int param, char *key, char *value)
 731 {
 732         struct expression *arg;
 733         struct expression *call;
 734
 735         call = expr;
 736         while (call->type == EXPR_ASSIGNMENT)
 737                 call = strip_expr(call->right);
 738         if (call->type != EXPR_CALL)
 739                 return;
 740
 741         if (!we_pass_user_data(call))
 742                 return;
 743
 744         if (param == -1) {
 745                 if (expr->type != EXPR_ASSIGNMENT)
 746                         return;
 747                 set_to_user_data(expr->left, key, value);
 748                 return;
 749         }
 750
 751         arg = get_argument_from_call_expr(call->args, param);
 752         if (!arg)
 753                 return;
 754         set_to_user_data(arg, key, value);
 755 }
 756
 757 static void returns_param_user_data_set(struct expression *expr, int param, char *key, char *value)
 758 {
 759         struct expression *arg;
 760
 761         func_gets_user_data = true;
 762
 763         if (param == -1) {
 764                 if (expr->type != EXPR_ASSIGNMENT)
 765                         return;
 766                 set_to_user_data(expr->left, key, value);
 767                 return;
 768         }
 769
 770         while (expr->type == EXPR_ASSIGNMENT)
 771                 expr = strip_expr(expr->right);
 772         if (expr->type != EXPR_CALL)
 773                 return;
 774
 775         arg = get_argument_from_call_expr(expr->args, param);
 776         if (!arg)
 777                 return;
 778         set_to_user_data(arg, key, value);
 779 }
 780
 781 static int has_empty_state(struct sm_state *sm)
 782 {
 783         struct sm_state *tmp;
 784
 785         FOR_EACH_PTR(sm->possible, tmp) {
 786                 if (!estate_rl(tmp->state))
 787                         return 1;
 788         } END_FOR_EACH_PTR(tmp);
 789
 790         return 0;
 791 }
 792
 793 static void param_set_to_user_data(int return_id, char *return_ranges, struct expression *expr)
 794 {
 795         struct sm_state *sm;
 796         struct smatch_state *start_state;
 797         struct range_list *rl;
 798         int param;
 799         const char *param_name;
 800
 801         FOR_EACH_MY_SM(my_id, __get_cur_stree(), sm) {
 802                 if (has_empty_state(sm))
 803                         continue;
 804
 805                 param = get_param_num_from_sym(sm->sym);
 806                 if (param < 0) {
 807                         if (expr_to_sym(expr) == sm->sym)
 808                                 param = -1;
 809                         else
 810                                 continue;
 811                 }
 812
 813                 /* The logic here was that if we were passed in a user data then
 814                  * we don't record that.  It's like the difference between
 815                  * param_filter and param_set.  When I think about it, I'm not
 816                  * sure it actually works.  It's probably harmless because we
 817                  * checked earlier that we're not returning a parameter...
 818                  * Let's mark this as a TODO.
 819                  */
 820                 start_state = get_state_stree(start_states, my_id, sm->name, sm->sym);
 821                 if (start_state && rl_equiv(estate_rl(sm->state), estate_rl(start_state)))
 822                         continue;
 823
 824                 param_name = get_param_name(sm);
 825                 if (!param_name)
 826                         continue;
 827                 if (strcmp(param_name, "$") == 0)
 828                         continue;
 829
 830                 sql_insert_return_states(return_id, return_ranges,
 831                                          func_gets_user_data ? USER_DATA3_SET : USER_DATA3,
 832                                          param, param_name, show_rl(estate_rl(sm->state)));
 833         } END_FOR_EACH_SM(sm);
 834
 835         if (get_user_rl(expr, &rl)) {
 836                 sql_insert_return_states(return_id, return_ranges,
 837                                          func_gets_user_data ? USER_DATA3_SET : USER_DATA3,
 838                                          -1, "$", show_rl(rl));
 839         }
 840 }
 841
 842 static struct int_stack *gets_data_stack;
 843 static void match_function_def(struct symbol *sym)
 844 {
 845         func_gets_user_data = false;
 846 }
 847
 848 static void match_inline_start(struct expression *expr)
 849 {
 850         push_int(&gets_data_stack, func_gets_user_data);
 851 }
 852
 853 static void match_inline_end(struct expression *expr)
 854 {
 855         func_gets_user_data = pop_int(&gets_data_stack);
 856 }
 857
 858 void check_user_data2(int id)
 859 {
 860         int i;
 861
 862         my_id = id;
 863
 864         if (option_project != PROJ_KERNEL)
 865                 return;
 866
 867         add_hook(&match_function_def, FUNC_DEF_HOOK);
 868         add_hook(&match_inline_start, INLINE_FN_START);
 869         add_hook(&match_inline_end, INLINE_FN_END);
 870
 871         add_hook(&save_start_states, AFTER_DEF_HOOK);
 872         add_hook(&free_start_states, AFTER_FUNC_HOOK);
 873         add_hook(&match_save_states, INLINE_FN_START);
 874         add_hook(&match_restore_states, INLINE_FN_END);
 875
 876         add_unmatched_state_hook(my_id, &empty_state);
 877         add_pre_merge_hook(my_id, &pre_merge_hook);
 878         add_merge_hook(my_id, &merge_estates);
 879
 880         add_function_hook("copy_from_user", &match_user_copy, INT_PTR(0));
 881         add_function_hook("__copy_from_user", &match_user_copy, INT_PTR(0));
 882         add_function_hook("memcpy_fromiovec", &match_user_copy, INT_PTR(0));
 883         for (i = 0; i < ARRAY_SIZE(kstr_funcs); i++)
 884                 add_function_hook(kstr_funcs[i], &match_user_copy, INT_PTR(2));
 885
 886         add_function_assign_hook("simple_strtol", &match_simple_strtoul, NULL);
 887         add_function_assign_hook("simple_strtoll", &match_simple_strtoul, NULL);
 888         add_function_assign_hook("simple_strtoul", &match_simple_strtoul, NULL);
 889         add_function_assign_hook("simple_strtoull", &match_simple_strtoul, NULL);
 890
 891         add_function_hook("sscanf", &match_sscanf, NULL);
 892
 893         add_function_assign_hook("memdup_user", &match_user_assign_function, NULL);
 894         add_function_assign_hook("kmap_atomic", &match_user_assign_function, NULL);
 895         add_function_assign_hook("skb_network_header", &match_user_assign_function, NULL);
 896
 897         add_hook(&match_syscall_definition, AFTER_DEF_HOOK);
 898
 899         add_hook(&match_assign, ASSIGNMENT_HOOK);
 900         add_hook(&match_condition, CONDITION_HOOK);
 901
 902         add_hook(&match_call_info, FUNCTION_CALL_HOOK);
 903         add_member_info_callback(my_id, struct_member_callback);
 904         select_caller_info_hook(set_param_user_data, USER_DATA3);
 905         select_return_states_hook(USER_DATA3, &returns_param_user_data);
 906         select_return_states_hook(USER_DATA3_SET, &returns_param_user_data_set);
 907         add_split_return_callback(&param_set_to_user_data);
 908 }
 909
 910 void check_user_data3(int id)
 911 {
 912         my_call_id = id;
 913
 914         if (option_project != PROJ_KERNEL)
 915                 return;
 916         select_caller_info_hook(set_called, INTERNAL);
 917 }
 918