check_user_data2.c

   1 /*
   2  * Copyright (C) 2011 Dan Carpenter.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public License
   6  * as published by the Free Software Foundation; either version 2
   7  * of the License, or (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, see http://www.gnu.org/copyleft/gpl.txt
  16  */
  17
  18 /*
  19  * There are a couple checks that try to see if a variable
  20  * comes from the user.  It would be better to unify them
  21  * into one place.  Also it we should follow the data down
  22  * the call paths.  Hence this file.
  23  */
  24
  25 #include "smatch.h"
  26 #include "smatch_slist.h"
  27 #include "smatch_extra.h"
  28
  29 static int my_id;
  30 static int my_call_id;
  31
  32 STATE(called);
  33 static bool func_gets_user_data;
  34
  35 static const char * kstr_funcs[] = {
  36         "kstrtoull", "kstrtoll", "kstrtoul", "kstrtol", "kstrtouint",
  37         "kstrtoint", "kstrtou64", "kstrtos64", "kstrtou32", "kstrtos32",
  38         "kstrtou16", "kstrtos16", "kstrtou8", "kstrtos8", "kstrtoull_from_user"
  39         "kstrtoll_from_user", "kstrtoul_from_user", "kstrtol_from_user",
  40         "kstrtouint_from_user", "kstrtoint_from_user", "kstrtou16_from_user",
  41         "kstrtos16_from_user", "kstrtou8_from_user", "kstrtos8_from_user",
  42         "kstrtou64_from_user", "kstrtos64_from_user", "kstrtou32_from_user",
  43         "kstrtos32_from_user",
  44 };
  45
  46 static void set_points_to_user_data(struct expression *expr);
  47
  48 static struct stree *start_states;
  49 static struct stree_stack *saved_stack;
  50 static void save_start_states(struct statement *stmt)
  51 {
  52         start_states = clone_stree(__get_cur_stree());
  53 }
  54
  55 static void free_start_states(void)
  56 {
  57         free_stree(&start_states);
  58 }
  59
  60 static void match_save_states(struct expression *expr)
  61 {
  62         push_stree(&saved_stack, start_states);
  63         start_states = NULL;
  64 }
  65
  66 static void match_restore_states(struct expression *expr)
  67 {
  68         free_stree(&start_states);
  69         start_states = pop_stree(&saved_stack);
  70 }
  71
  72 static struct smatch_state *empty_state(struct sm_state *sm)
  73 {
  74         return alloc_estate_empty();
  75 }
  76
  77 static void pre_merge_hook(struct sm_state *sm)
  78 {
  79         struct smatch_state *user;
  80         struct smatch_state *extra;
  81         struct range_list *rl;
  82
  83         extra = get_state(SMATCH_EXTRA, sm->name, sm->sym);
  84         if (!extra || !estate_rl(extra))
  85                 return;
  86         user = get_state(my_id, sm->name, sm->sym);
  87         if (!user || !estate_rl(user))
  88                 return;
  89         rl = rl_intersection(estate_rl(user), estate_rl(extra));
  90         set_state(my_id, sm->name, sm->sym, alloc_estate_rl(clone_rl(rl)));
  91 }
  92
  93 static void tag_inner_struct_members(struct expression *expr, struct symbol *member)
  94 {
  95         struct expression *edge_member;
  96         struct symbol *base = get_real_base_type(member);
  97         struct symbol *tmp;
  98
  99         if (member->ident)
 100                 expr = member_expression(expr, '.', member->ident);
 101
 102         FOR_EACH_PTR(base->symbol_list, tmp) {
 103                 struct symbol *type;
 104
 105                 type = get_real_base_type(tmp);
 106                 if (!type)
 107                         continue;
 108
 109                 if (type->type == SYM_UNION || type->type == SYM_STRUCT) {
 110                         tag_inner_struct_members(expr, tmp);
 111                         continue;
 112                 }
 113
 114                 if (!tmp->ident)
 115                         continue;
 116
 117                 edge_member = member_expression(expr, '.', tmp->ident);
 118                 set_state_expr(my_id, edge_member, alloc_estate_whole(type));
 119         } END_FOR_EACH_PTR(tmp);
 120 }
 121
 122 static void tag_struct_members(struct symbol *type, struct expression *expr)
 123 {
 124         struct symbol *tmp;
 125         struct expression *member;
 126         int op = '*';
 127
 128         if (expr->type == EXPR_PREOP && expr->op == '&') {
 129                 expr = strip_expr(expr->unop);
 130                 op = '.';
 131         }
 132
 133         FOR_EACH_PTR(type->symbol_list, tmp) {
 134                 type = get_real_base_type(tmp);
 135                 if (!type)
 136                         continue;
 137
 138                 if (type->type == SYM_UNION || type->type == SYM_STRUCT) {
 139                         tag_inner_struct_members(expr, tmp);
 140                         continue;
 141                 }
 142
 143                 if (!tmp->ident)
 144                         continue;
 145
 146                 member = member_expression(expr, op, tmp->ident);
 147                 set_state_expr(my_id, member, alloc_estate_whole(get_type(member)));
 148
 149                 if (type->type == SYM_ARRAY)
 150                         set_points_to_user_data(member);
 151         } END_FOR_EACH_PTR(tmp);
 152 }
 153
 154 static void tag_base_type(struct expression *expr)
 155 {
 156         if (expr->type == EXPR_PREOP && expr->op == '&')
 157                 expr = strip_expr(expr->unop);
 158         else
 159                 expr = deref_expression(expr);
 160         set_state_expr(my_id, expr, alloc_estate_whole(get_type(expr)));
 161 }
 162
 163 static void tag_as_user_data(struct expression *expr)
 164 {
 165         struct symbol *type;
 166
 167         expr = strip_expr(expr);
 168
 169         type = get_type(expr);
 170         if (!type || type->type != SYM_PTR)
 171                 return;
 172         type = get_real_base_type(type);
 173         if (!type)
 174                 return;
 175         if (type == &void_ctype) {
 176                 set_state_expr(my_id, deref_expression(expr), alloc_estate_whole(&ulong_ctype));
 177                 return;
 178         }
 179         if (type->type == SYM_BASETYPE)
 180                 tag_base_type(expr);
 181         if (type->type == SYM_STRUCT) {
 182                 if (expr->type != EXPR_PREOP || expr->op != '&')
 183                         expr = deref_expression(expr);
 184                 else
 185                         set_state_expr(my_id, deref_expression(expr), alloc_estate_whole(&ulong_ctype));
 186                 tag_struct_members(type, expr);
 187         }
 188 }
 189
 190 static void match_user_copy(const char *fn, struct expression *expr, void *_param)
 191 {
 192         int param = PTR_INT(_param);
 193         struct expression *dest;
 194
 195         func_gets_user_data = true;
 196
 197         dest = get_argument_from_call_expr(expr->args, param);
 198         dest = strip_expr(dest);
 199         if (!dest)
 200                 return;
 201         tag_as_user_data(dest);
 202 }
 203
 204 static void match_sscanf(const char *fn, struct expression *expr, void *unused)
 205 {
 206         struct expression *arg;
 207         int i;
 208
 209         func_gets_user_data = true;
 210
 211         i = -1;
 212         FOR_EACH_PTR(expr->args, arg) {
 213                 i++;
 214                 if (i < 2)
 215                         continue;
 216                 tag_as_user_data(arg);
 217         } END_FOR_EACH_PTR(arg);
 218 }
 219
 220 static int points_to_user_data(struct expression *expr)
 221 {
 222         struct smatch_state *state;
 223         char buf[256];
 224         struct symbol *sym;
 225         char *name;
 226         int ret = 0;
 227
 228         expr = strip_expr(expr);
 229
 230         if (expr->type == EXPR_BINOP && expr->op == '+') {
 231                 if (points_to_user_data(expr->left))
 232                         return 1;
 233                 if (points_to_user_data(expr->right))
 234                         return 1;
 235                 return 0;
 236         }
 237
 238         name = expr_to_var_sym(expr, &sym);
 239         if (!name || !sym)
 240                 goto free;
 241         snprintf(buf, sizeof(buf), "*%s", name);
 242         state = get_state(my_id, buf, sym);
 243         if (state && estate_rl(state))
 244                 ret = 1;
 245 free:
 246         free_string(name);
 247         return ret;
 248 }
 249
 250 static void set_points_to_user_data(struct expression *expr)
 251 {
 252         char *name;
 253         struct symbol *sym;
 254         char buf[256];
 255
 256         name = expr_to_var_sym(expr, &sym);
 257         if (!name || !sym)
 258                 goto free;
 259         snprintf(buf, sizeof(buf), "*%s", name);
 260         set_state(my_id, buf, sym, alloc_estate_whole(&llong_ctype));
 261 free:
 262         free_string(name);
 263 }
 264
 265 static int is_skb_data(struct expression *expr)
 266 {
 267         struct symbol *sym;
 268
 269         expr = strip_expr(expr);
 270         if (!expr)
 271                 return 0;
 272         if (expr->type != EXPR_DEREF || expr->op != '.')
 273                 return 0;
 274
 275         if (!expr->member)
 276                 return 0;
 277         if (strcmp(expr->member->name, "data") != 0)
 278                 return 0;
 279
 280         sym = expr_to_sym(expr->deref);
 281         if (!sym)
 282                 return 0;
 283         sym = get_real_base_type(sym);
 284         if (!sym || sym->type != SYM_PTR)
 285                 return 0;
 286         sym = get_real_base_type(sym);
 287         if (!sym || sym->type != SYM_STRUCT || !sym->ident)
 288                 return 0;
 289         if (strcmp(sym->ident->name, "sk_buff") != 0)
 290                 return 0;
 291
 292         return 1;
 293 }
 294
 295 static int comes_from_skb_data(struct expression *expr)
 296 {
 297         expr = strip_expr(expr);
 298         if (!expr || expr->type != EXPR_PREOP || expr->op != '*')
 299                 return 0;
 300
 301         expr = strip_expr(expr->unop);
 302         if (expr->type == EXPR_BINOP && expr->op == '+')
 303                 expr = strip_expr(expr->left);
 304
 305         return is_skb_data(expr);
 306 }
 307
 308 static int handle_struct_assignment(struct expression *expr)
 309 {
 310         struct expression *right;
 311         struct symbol *left_type, *right_type;
 312
 313         left_type = get_type(expr->left);
 314         if (!left_type || left_type->type != SYM_PTR)
 315                 return 0;
 316         left_type = get_real_base_type(left_type);
 317         if (!left_type || left_type->type != SYM_STRUCT)
 318                 return 0;
 319
 320         /*
 321          * Ignore struct to struct assignments because for those we look at the
 322          * individual members.
 323          */
 324         right = strip_expr(expr->right);
 325         right_type = get_type(right);
 326         if (!right_type || right_type->type != SYM_PTR)
 327                 return 0;
 328
 329         /* If we are assigning struct members then normally that is handled
 330          * by fake assignments, however if we cast one struct to a different
 331          * of struct then we handle that here.
 332          */
 333         right_type = get_real_base_type(right_type);
 334         if (right_type == left_type)
 335                 return 0;
 336
 337         if (!points_to_user_data(right) && !is_skb_data(right))
 338                 return 0;
 339
 340         tag_as_user_data(expr->left);
 341         return 1;
 342 }
 343
 344 static int handle_get_user(struct expression *expr)
 345 {
 346         char *name;
 347         int ret = 0;
 348
 349         name = get_macro_name(expr->pos);
 350         if (!name || strcmp(name, "get_user") != 0)
 351                 return 0;
 352
 353         name = expr_to_var(expr->right);
 354         if (!name || strcmp(name, "__val_gu") != 0)
 355                 goto free;
 356         set_state_expr(my_id, expr->left, alloc_estate_whole(get_type(expr->left)));
 357         ret = 1;
 358 free:
 359         free_string(name);
 360         return ret;
 361 }
 362
 363 static void match_assign(struct expression *expr)
 364 {
 365         struct range_list *rl;
 366
 367         if (is_fake_call(expr->right))
 368                 return;
 369         if (handle_get_user(expr))
 370                 return;
 371         if (points_to_user_data(expr->right))
 372                 set_points_to_user_data(expr->left);
 373         if (handle_struct_assignment(expr))
 374                 return;
 375
 376         if (!get_user_rl(expr->right, &rl))
 377                 goto clear_old_state;
 378
 379         rl = cast_rl(get_type(expr->left), rl);
 380         set_state_expr(my_id, expr->left, alloc_estate_rl(rl));
 381
 382         return;
 383
 384 clear_old_state:
 385         if (get_state_expr(my_id, expr->left))
 386                 set_state_expr(my_id, expr->left, alloc_estate_empty());
 387 }
 388
 389 static void match_condition(struct expression *expr)
 390 {
 391         struct smatch_state *left_orig = NULL;
 392         struct smatch_state *right_orig = NULL;
 393
 394         if (expr->type != EXPR_COMPARE || expr->op != SPECIAL_EQUAL)
 395                 return;
 396
 397         left_orig = get_state_expr(my_id, expr->left);
 398         right_orig = get_state_expr(my_id, expr->right);
 399
 400         if (!left_orig && !right_orig)
 401                 return;
 402         if (left_orig && right_orig)
 403                 return;
 404
 405         if (left_orig)
 406                 set_true_false_states_expr(my_id, expr->left, alloc_estate_empty(), NULL);
 407         else
 408                 set_true_false_states_expr(my_id, expr->right, alloc_estate_empty(), NULL);
 409 }
 410
 411 static void match_user_assign_function(const char *fn, struct expression *expr, void *unused)
 412 {
 413         func_gets_user_data = true;
 414
 415         tag_as_user_data(expr->left);
 416         set_points_to_user_data(expr->left);
 417 }
 418
 419 static void match_simple_strtoul(const char *fn, struct expression *expr, void *unused)
 420 {
 421         func_gets_user_data = true;
 422
 423         set_state_expr(my_id, expr->left, alloc_estate_whole(get_type(expr->left)));
 424 }
 425
 426 static int get_user_macro_rl(struct expression *expr, struct range_list **rl)
 427 {
 428         char *macro;
 429
 430         if (!expr)
 431                 return 0;
 432         macro = get_macro_name(expr->pos);
 433
 434         if (!macro)
 435                 return 0;
 436
 437         if (strcmp(macro, "ntohl") == 0) {
 438                 *rl = alloc_whole_rl(&uint_ctype);
 439                 return 1;
 440         }
 441         if (strcmp(macro, "ntohs") == 0) {
 442                 *rl = alloc_whole_rl(&ushort_ctype);
 443                 return 1;
 444         }
 445         return 0;
 446 }
 447
 448 struct db_info {
 449         struct range_list *rl;
 450         struct expression *call;
 451 };
 452 static int returned_rl_callback(void *_info, int argc, char **argv, char **azColName)
 453 {
 454         struct db_info *db_info = _info;
 455         struct range_list *rl;
 456         char *return_ranges = argv[0];
 457         char *user_ranges = argv[1];
 458         struct expression *arg;
 459         int comparison;
 460
 461         if (argc != 2)
 462                 return 0;
 463
 464         call_results_to_rl(db_info->call, get_type(db_info->call), user_ranges, &rl);
 465         if (str_to_comparison_arg(return_ranges, db_info->call, &comparison, &arg) &&
 466             comparison == SPECIAL_EQUAL) {
 467                 struct range_list *orig_rl;
 468
 469                 if (!get_user_rl(arg, &orig_rl))
 470                         return 0;
 471                 rl = rl_intersection(rl, orig_rl);
 472                 if (!rl)
 473                         return 0;
 474         }
 475         db_info->rl = rl_union(db_info->rl, rl);
 476
 477         return 0;
 478 }
 479
 480 static int has_user_data(struct symbol *sym)
 481 {
 482         struct sm_state *tmp;
 483
 484         FOR_EACH_MY_SM(my_id, __get_cur_stree(), tmp) {
 485                 if (tmp->sym == sym)
 486                         return 1;
 487         } END_FOR_EACH_SM(tmp);
 488         return 0;
 489 }
 490
 491 static int we_pass_user_data(struct expression *call)
 492 {
 493         struct expression *arg;
 494         struct symbol *sym;
 495
 496         FOR_EACH_PTR(call->args, arg) {
 497                 sym = expr_to_sym(arg);
 498                 if (!sym)
 499                         continue;
 500                 if (has_user_data(sym))
 501                         return 1;
 502         } END_FOR_EACH_PTR(arg);
 503
 504         return 0;
 505 }
 506
 507 static int db_returned_user_rl(struct expression *call, struct range_list **rl)
 508 {
 509         struct db_info db_info = {};
 510
 511         /* for function pointers assume everything is used */
 512         if (call->fn->type != EXPR_SYMBOL)
 513                 return 0;
 514         if (is_fake_call(call))
 515                 return 0;
 516
 517         db_info.call = call;
 518         run_sql(&returned_rl_callback, &db_info,
 519                 "select return, value from return_states where %s and type = %d and parameter = -1 and key = '$';",
 520                 get_static_filter(call->fn->symbol), USER_DATA3_SET);
 521         if (db_info.rl) {
 522                 func_gets_user_data = true;
 523                 *rl = db_info.rl;
 524                 return 1;
 525         }
 526
 527         run_sql(&returned_rl_callback, &db_info,
 528                 "select return, value from return_states where %s and type = %d and parameter = -1 and key = '$';",
 529                 get_static_filter(call->fn->symbol), USER_DATA3);
 530         if (db_info.rl) {
 531                 if (!we_pass_user_data(call))
 532                         return 0;
 533                 func_gets_user_data = true;
 534                 *rl = db_info.rl;
 535                 return 1;
 536         }
 537
 538         return 0;
 539 }
 540
 541 static int user_data_flag;
 542 static struct range_list *var_user_rl(struct expression *expr)
 543 {
 544         struct smatch_state *state;
 545         struct range_list *rl;
 546         struct range_list *absolute_rl;
 547
 548         if (get_user_macro_rl(expr, &rl))
 549                 goto found;
 550
 551         if (comes_from_skb_data(expr)) {
 552                 rl = alloc_whole_rl(get_type(expr));
 553                 goto found;
 554         }
 555
 556         state = get_state_expr(my_id, expr);
 557         if (state && estate_rl(state)) {
 558                 rl = estate_rl(state);
 559                 goto found;
 560         }
 561
 562         if (expr->type == EXPR_CALL && db_returned_user_rl(expr, &rl))
 563                 goto found;
 564
 565         return NULL;
 566 found:
 567         user_data_flag = 1;
 568         absolute_rl = var_to_absolute_rl(expr);
 569         return clone_rl(rl_intersection(rl, absolute_rl));
 570 }
 571
 572 int get_user_rl(struct expression *expr, struct range_list **rl)
 573 {
 574
 575         user_data_flag = 0;
 576         custom_get_absolute_rl(expr, &var_user_rl, rl);
 577         if (!user_data_flag) {
 578                 *rl = NULL;
 579                 return 0;
 580         }
 581         return 1;
 582 }
 583
 584 int get_user_rl_var_sym(const char *name, struct symbol *sym, struct range_list **rl)
 585 {
 586         struct smatch_state *state;
 587
 588         state = get_state(my_id, name, sym);
 589         if (state && estate_rl(state)) {
 590                 *rl = estate_rl(state);
 591                 return 1;
 592         }
 593         return 0;
 594 }
 595
 596 static void match_call_info(struct expression *expr)
 597 {
 598         struct range_list *rl;
 599         struct expression *arg;
 600         int i = 0;
 601
 602         i = -1;
 603         FOR_EACH_PTR(expr->args, arg) {
 604                 i++;
 605
 606                 if (!get_user_rl(arg, &rl))
 607                         continue;
 608
 609                 sql_insert_caller_info(expr, USER_DATA3, i, "$", show_rl(rl));
 610         } END_FOR_EACH_PTR(arg);
 611 }
 612
 613 static void struct_member_callback(struct expression *call, int param, char *printed_name, struct sm_state *sm)
 614 {
 615         struct smatch_state *state;
 616         struct range_list *rl;
 617
 618         if (strcmp(sm->state->name, "") == 0)
 619                 return;
 620
 621         state = get_state(SMATCH_EXTRA, sm->name, sm->sym);
 622         if (!state || !estate_rl(state))
 623                 rl = estate_rl(sm->state);
 624         else
 625                 rl = rl_intersection(estate_rl(sm->state), estate_rl(state));
 626
 627         sql_insert_caller_info(call, USER_DATA3, param, printed_name, show_rl(rl));
 628 }
 629
 630 static void set_param_user_data(const char *name, struct symbol *sym, char *key, char *value)
 631 {
 632         struct range_list *rl = NULL;
 633         struct smatch_state *state;
 634         struct symbol *type;
 635         char fullname[256];
 636
 637         if (strcmp(key, "*$") == 0)
 638                 snprintf(fullname, sizeof(fullname), "*%s", name);
 639         else if (strncmp(key, "$", 1) == 0)
 640                 snprintf(fullname, 256, "%s%s", name, key + 1);
 641         else
 642                 return;
 643
 644         type = get_member_type_from_key(symbol_expression(sym), key);
 645
 646         /* if the caller passes a void pointer with user data */
 647         if (strcmp(key, "*$") == 0 && type && type != &void_ctype) {
 648                 struct expression *expr = symbol_expression(sym);
 649
 650                 tag_as_user_data(expr);
 651                 set_points_to_user_data(expr);
 652                 return;
 653         }
 654         str_to_rl(type, value, &rl);
 655         state = alloc_estate_rl(rl);
 656         set_state(my_id, fullname, sym, state);
 657 }
 658
 659 static void set_called(const char *name, struct symbol *sym, char *key, char *value)
 660 {
 661         set_state(my_call_id, "this_function", NULL, &called);
 662 }
 663
 664 static void match_syscall_definition(struct symbol *sym)
 665 {
 666         struct symbol *arg;
 667         char *macro;
 668         char *name;
 669         int is_syscall = 0;
 670
 671         macro = get_macro_name(sym->pos);
 672         if (macro &&
 673             (strncmp("SYSCALL_DEFINE", macro, strlen("SYSCALL_DEFINE")) == 0 ||
 674              strncmp("COMPAT_SYSCALL_DEFINE", macro, strlen("COMPAT_SYSCALL_DEFINE")) == 0))
 675                 is_syscall = 1;
 676
 677         name = get_function();
 678         if (!option_no_db && get_state(my_call_id, "this_function", NULL) != &called) {
 679                 if (name && strncmp(name, "sys_", 4) == 0)
 680                         is_syscall = 1;
 681         }
 682
 683         if (name && strncmp(name, "compat_sys_", 11) == 0)
 684                 is_syscall = 1;
 685
 686         if (!is_syscall)
 687                 return;
 688
 689         FOR_EACH_PTR(sym->ctype.base_type->arguments, arg) {
 690                 set_state(my_id, arg->ident->name, arg, alloc_estate_whole(get_real_base_type(arg)));
 691         } END_FOR_EACH_PTR(arg);
 692 }
 693
 694 static void set_to_user_data(struct expression *expr, char *key, char *value)
 695 {
 696         char *name;
 697         struct symbol *sym;
 698         struct symbol *type;
 699         struct range_list *rl = NULL;
 700
 701         type = get_member_type_from_key(expr, key);
 702         name = get_variable_from_key(expr, key, &sym);
 703         if (!name || !sym)
 704                 goto free;
 705
 706         call_results_to_rl(expr, type, value, &rl);
 707
 708         set_state(my_id, name, sym, alloc_estate_rl(rl));
 709 free:
 710         free_string(name);
 711
 712 }
 713
 714 static void returns_param_user_data(struct expression *expr, int param, char *key, char *value)
 715 {
 716         struct expression *arg;
 717         struct expression *call;
 718
 719         call = expr;
 720         while (call->type == EXPR_ASSIGNMENT)
 721                 call = strip_expr(call->right);
 722         if (call->type != EXPR_CALL)
 723                 return;
 724
 725         if (!we_pass_user_data(call))
 726                 return;
 727
 728         if (param == -1) {
 729                 if (expr->type != EXPR_ASSIGNMENT)
 730                         return;
 731                 set_to_user_data(expr->left, key, value);
 732                 return;
 733         }
 734
 735         arg = get_argument_from_call_expr(call->args, param);
 736         if (!arg)
 737                 return;
 738         set_to_user_data(arg, key, value);
 739 }
 740
 741 static void returns_param_user_data_set(struct expression *expr, int param, char *key, char *value)
 742 {
 743         struct expression *arg;
 744
 745         func_gets_user_data = true;
 746
 747         if (param == -1) {
 748                 if (expr->type != EXPR_ASSIGNMENT)
 749                         return;
 750                 set_to_user_data(expr->left, key, value);
 751                 return;
 752         }
 753
 754         while (expr->type == EXPR_ASSIGNMENT)
 755                 expr = strip_expr(expr->right);
 756         if (expr->type != EXPR_CALL)
 757                 return;
 758
 759         arg = get_argument_from_call_expr(expr->args, param);
 760         if (!arg)
 761                 return;
 762         set_to_user_data(arg, key, value);
 763 }
 764
 765 static int has_empty_state(struct sm_state *sm)
 766 {
 767         struct sm_state *tmp;
 768
 769         FOR_EACH_PTR(sm->possible, tmp) {
 770                 if (!estate_rl(tmp->state))
 771                         return 1;
 772         } END_FOR_EACH_PTR(tmp);
 773
 774         return 0;
 775 }
 776
 777 static void param_set_to_user_data(int return_id, char *return_ranges, struct expression *expr)
 778 {
 779         struct sm_state *sm;
 780         struct smatch_state *start_state;
 781         struct range_list *rl;
 782         int param;
 783         const char *param_name;
 784
 785         FOR_EACH_MY_SM(my_id, __get_cur_stree(), sm) {
 786                 if (has_empty_state(sm))
 787                         continue;
 788
 789                 param = get_param_num_from_sym(sm->sym);
 790                 if (param < 0) {
 791                         if (expr_to_sym(expr) == sm->sym)
 792                                 param = -1;
 793                         else
 794                                 continue;
 795                 }
 796
 797                 /* The logic here was that if we were passed in a user data then
 798                  * we don't record that.  It's like the difference between
 799                  * param_filter and param_set.  When I think about it, I'm not
 800                  * sure it actually works.  It's probably harmless because we
 801                  * checked earlier that we're not returning a parameter...
 802                  * Let's mark this as a TODO.
 803                  */
 804                 start_state = get_state_stree(start_states, my_id, sm->name, sm->sym);
 805                 if (start_state && estates_equiv(sm->state, start_state))
 806                         continue;
 807
 808                 param_name = get_param_name(sm);
 809                 if (!param_name)
 810                         continue;
 811                 if (strcmp(param_name, "$") == 0)
 812                         continue;
 813
 814                 sql_insert_return_states(return_id, return_ranges,
 815                                          func_gets_user_data ? USER_DATA3_SET : USER_DATA3,
 816                                          param, param_name, show_rl(estate_rl(sm->state)));
 817         } END_FOR_EACH_SM(sm);
 818
 819         if (get_user_rl(expr, &rl)) {
 820                 sql_insert_return_states(return_id, return_ranges,
 821                                          func_gets_user_data ? USER_DATA3_SET : USER_DATA3,
 822                                          -1, "$", show_rl(rl));
 823         }
 824 }
 825
 826 static void match_function_def(struct symbol *sym)
 827 {
 828         func_gets_user_data = false;
 829 }
 830
 831 void check_user_data2(int id)
 832 {
 833         int i;
 834
 835         my_id = id;
 836
 837         if (option_project != PROJ_KERNEL)
 838                 return;
 839
 840         add_hook(&match_function_def, FUNC_DEF_HOOK);
 841
 842         add_hook(&save_start_states, AFTER_DEF_HOOK);
 843         add_hook(&free_start_states, AFTER_FUNC_HOOK);
 844         add_hook(&match_save_states, INLINE_FN_START);
 845         add_hook(&match_restore_states, INLINE_FN_END);
 846
 847         add_unmatched_state_hook(my_id, &empty_state);
 848         add_pre_merge_hook(my_id, &pre_merge_hook);
 849         add_merge_hook(my_id, &merge_estates);
 850
 851         add_function_hook("copy_from_user", &match_user_copy, INT_PTR(0));
 852         add_function_hook("__copy_from_user", &match_user_copy, INT_PTR(0));
 853         add_function_hook("memcpy_fromiovec", &match_user_copy, INT_PTR(0));
 854         for (i = 0; i < ARRAY_SIZE(kstr_funcs); i++)
 855                 add_function_hook(kstr_funcs[i], &match_user_copy, INT_PTR(2));
 856
 857         add_function_assign_hook("simple_strtol", &match_simple_strtoul, NULL);
 858         add_function_assign_hook("simple_strtoll", &match_simple_strtoul, NULL);
 859         add_function_assign_hook("simple_strtoul", &match_simple_strtoul, NULL);
 860         add_function_assign_hook("simple_strtoull", &match_simple_strtoul, NULL);
 861
 862         add_function_hook("sscanf", &match_sscanf, NULL);
 863
 864         add_function_assign_hook("memdup_user", &match_user_assign_function, NULL);
 865         add_function_assign_hook("kmap_atomic", &match_user_assign_function, NULL);
 866         add_function_assign_hook("skb_network_header", &match_user_assign_function, NULL);
 867
 868         add_hook(&match_syscall_definition, AFTER_DEF_HOOK);
 869
 870         add_hook(&match_assign, ASSIGNMENT_HOOK);
 871         add_hook(&match_condition, CONDITION_HOOK);
 872
 873         add_hook(&match_call_info, FUNCTION_CALL_HOOK);
 874         add_member_info_callback(my_id, struct_member_callback);
 875         select_caller_info_hook(set_param_user_data, USER_DATA3);
 876         select_return_states_hook(USER_DATA3, &returns_param_user_data);
 877         select_return_states_hook(USER_DATA3_SET, &returns_param_user_data_set);
 878         add_split_return_callback(&param_set_to_user_data);
 879 }
 880
 881 void check_user_data3(int id)
 882 {
 883         my_call_id = id;
 884
 885         if (option_project != PROJ_KERNEL)
 886                 return;
 887         select_caller_info_hook(set_called, INTERNAL);
 888 }
 889