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