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 extra_nomod_hook(const char *name, struct symbol *sym, struct expression *expr, struct smatch_state *state)
  97 {
  98         struct smatch_state *user;
  99         struct range_list *rl;
 100
 101         user = get_state(my_id, name, sym);
 102         if (!user)
 103                 return;
 104         rl = rl_intersection(estate_rl(user), estate_rl(state));
 105         if (rl_equiv(rl, estate_rl(user)))
 106                 return;
 107         set_state(my_id, name, sym, alloc_estate_rl(rl));
 108 }
 109
 110 static void tag_inner_struct_members(struct expression *expr, struct symbol *member)
 111 {
 112         struct expression *edge_member;
 113         struct symbol *base = get_real_base_type(member);
 114         struct symbol *tmp;
 115
 116         if (member->ident)
 117                 expr = member_expression(expr, '.', member->ident);
 118
 119         FOR_EACH_PTR(base->symbol_list, tmp) {
 120                 struct symbol *type;
 121
 122                 type = get_real_base_type(tmp);
 123                 if (!type)
 124                         continue;
 125
 126                 if (type->type == SYM_UNION || type->type == SYM_STRUCT) {
 127                         tag_inner_struct_members(expr, tmp);
 128                         continue;
 129                 }
 130
 131                 if (!tmp->ident)
 132                         continue;
 133
 134                 edge_member = member_expression(expr, '.', tmp->ident);
 135                 set_state_expr(my_id, edge_member, alloc_estate_whole(type));
 136         } END_FOR_EACH_PTR(tmp);
 137 }
 138
 139 static void tag_struct_members(struct symbol *type, struct expression *expr)
 140 {
 141         struct symbol *tmp;
 142         struct expression *member;
 143         int op = '*';
 144
 145         if (expr->type == EXPR_PREOP && expr->op == '&') {
 146                 expr = strip_expr(expr->unop);
 147                 op = '.';
 148         }
 149
 150         FOR_EACH_PTR(type->symbol_list, tmp) {
 151                 type = get_real_base_type(tmp);
 152                 if (!type)
 153                         continue;
 154
 155                 if (type->type == SYM_UNION || type->type == SYM_STRUCT) {
 156                         tag_inner_struct_members(expr, tmp);
 157                         continue;
 158                 }
 159
 160                 if (!tmp->ident)
 161                         continue;
 162
 163                 member = member_expression(expr, op, tmp->ident);
 164                 set_state_expr(my_id, member, alloc_estate_whole(get_type(member)));
 165
 166                 if (type->type == SYM_ARRAY)
 167                         set_points_to_user_data(member);
 168         } END_FOR_EACH_PTR(tmp);
 169 }
 170
 171 static void tag_base_type(struct expression *expr)
 172 {
 173         if (expr->type == EXPR_PREOP && expr->op == '&')
 174                 expr = strip_expr(expr->unop);
 175         else
 176                 expr = deref_expression(expr);
 177         set_state_expr(my_id, expr, alloc_estate_whole(get_type(expr)));
 178 }
 179
 180 static void tag_as_user_data(struct expression *expr)
 181 {
 182         struct symbol *type;
 183
 184         expr = strip_expr(expr);
 185
 186         type = get_type(expr);
 187         if (!type || type->type != SYM_PTR)
 188                 return;
 189         type = get_real_base_type(type);
 190         if (!type)
 191                 return;
 192         if (type == &void_ctype) {
 193                 set_state_expr(my_id, deref_expression(expr), alloc_estate_whole(&ulong_ctype));
 194                 return;
 195         }
 196         if (type->type == SYM_BASETYPE)
 197                 tag_base_type(expr);
 198         if (type->type == SYM_STRUCT || type->type == SYM_UNION) {
 199                 if (expr->type != EXPR_PREOP || expr->op != '&')
 200                         expr = deref_expression(expr);
 201                 else
 202                         set_state_expr(my_id, deref_expression(expr), alloc_estate_whole(&ulong_ctype));
 203                 tag_struct_members(type, expr);
 204         }
 205 }
 206
 207 static void match_user_copy(const char *fn, struct expression *expr, void *_param)
 208 {
 209         int param = PTR_INT(_param);
 210         struct expression *dest;
 211
 212         func_gets_user_data = true;
 213
 214         dest = get_argument_from_call_expr(expr->args, param);
 215         dest = strip_expr(dest);
 216         if (!dest)
 217                 return;
 218         tag_as_user_data(dest);
 219 }
 220
 221 static void match_sscanf(const char *fn, struct expression *expr, void *unused)
 222 {
 223         struct expression *arg;
 224         int i;
 225
 226         func_gets_user_data = true;
 227
 228         i = -1;
 229         FOR_EACH_PTR(expr->args, arg) {
 230                 i++;
 231                 if (i < 2)
 232                         continue;
 233                 tag_as_user_data(arg);
 234         } END_FOR_EACH_PTR(arg);
 235 }
 236
 237 static int is_skb_data(struct expression *expr)
 238 {
 239         struct symbol *sym;
 240
 241         if (!expr)
 242                 return 0;
 243
 244         if (expr->type == EXPR_BINOP && expr->op == '+')
 245                 return is_skb_data(expr->left);
 246
 247         expr = strip_expr(expr);
 248         if (!expr)
 249                 return 0;
 250         if (expr->type != EXPR_DEREF || expr->op != '.')
 251                 return 0;
 252
 253         if (!expr->member)
 254                 return 0;
 255         if (strcmp(expr->member->name, "data") != 0)
 256                 return 0;
 257
 258         sym = expr_to_sym(expr->deref);
 259         if (!sym)
 260                 return 0;
 261         sym = get_real_base_type(sym);
 262         if (!sym || sym->type != SYM_PTR)
 263                 return 0;
 264         sym = get_real_base_type(sym);
 265         if (!sym || sym->type != SYM_STRUCT || !sym->ident)
 266                 return 0;
 267         if (strcmp(sym->ident->name, "sk_buff") != 0)
 268                 return 0;
 269
 270         return 1;
 271 }
 272
 273 static int points_to_user_data(struct expression *expr)
 274 {
 275         struct smatch_state *state;
 276         char buf[256];
 277         struct symbol *sym;
 278         char *name;
 279         int ret = 0;
 280
 281         expr = strip_expr(expr);
 282         if (!expr)
 283                 return 0;
 284         if (is_skb_data(expr))
 285                 return 1;
 286
 287         if (expr->type == EXPR_BINOP && expr->op == '+') {
 288                 if (points_to_user_data(expr->left))
 289                         return 1;
 290                 if (points_to_user_data(expr->right))
 291                         return 1;
 292                 return 0;
 293         }
 294
 295         name = expr_to_var_sym(expr, &sym);
 296         if (!name || !sym)
 297                 goto free;
 298         snprintf(buf, sizeof(buf), "*%s", name);
 299         state = get_state(my_id, buf, sym);
 300         if (state && estate_rl(state))
 301                 ret = 1;
 302 free:
 303         free_string(name);
 304         return ret;
 305 }
 306
 307 static void set_points_to_user_data(struct expression *expr)
 308 {
 309         char *name;
 310         struct symbol *sym;
 311         char buf[256];
 312
 313         name = expr_to_var_sym(expr, &sym);
 314         if (!name || !sym)
 315                 goto free;
 316         snprintf(buf, sizeof(buf), "*%s", name);
 317         set_state(my_id, buf, sym, alloc_estate_whole(&llong_ctype));
 318 free:
 319         free_string(name);
 320 }
 321
 322 static int comes_from_skb_data(struct expression *expr)
 323 {
 324         expr = strip_expr(expr);
 325         if (!expr || expr->type != EXPR_PREOP || expr->op != '*')
 326                 return 0;
 327
 328         expr = strip_expr(expr->unop);
 329         if (!expr)
 330                 return 0;
 331         if (expr->type == EXPR_BINOP && expr->op == '+')
 332                 expr = strip_expr(expr->left);
 333
 334         return is_skb_data(expr);
 335 }
 336
 337 static int handle_struct_assignment(struct expression *expr)
 338 {
 339         struct expression *right;
 340         struct symbol *left_type, *right_type;
 341
 342         left_type = get_type(expr->left);
 343         if (!left_type || left_type->type != SYM_PTR)
 344                 return 0;
 345         left_type = get_real_base_type(left_type);
 346         if (!left_type)
 347                 return 0;
 348         if (left_type->type != SYM_STRUCT &&
 349             left_type->type != SYM_UNION)
 350                 return 0;
 351
 352         /*
 353          * Ignore struct to struct assignments because for those we look at the
 354          * individual members.
 355          */
 356         right = strip_expr(expr->right);
 357         right_type = get_type(right);
 358         if (!right_type || right_type->type != SYM_PTR)
 359                 return 0;
 360
 361         /* If we are assigning struct members then normally that is handled
 362          * by fake assignments, however if we cast one struct to a different
 363          * of struct then we handle that here.
 364          */
 365         right_type = get_real_base_type(right_type);
 366         if (right_type == left_type)
 367                 return 0;
 368
 369         if (!points_to_user_data(right))
 370                 return 0;
 371
 372         tag_as_user_data(expr->left);
 373         return 1;
 374 }
 375
 376 static int handle_get_user(struct expression *expr)
 377 {
 378         char *name;
 379         int ret = 0;
 380
 381         name = get_macro_name(expr->pos);
 382         if (!name || strcmp(name, "get_user") != 0)
 383                 return 0;
 384
 385         name = expr_to_var(expr->right);
 386         if (!name || strcmp(name, "__val_gu") != 0)
 387                 goto free;
 388         set_state_expr(my_id, expr->left, alloc_estate_whole(get_type(expr->left)));
 389         ret = 1;
 390 free:
 391         free_string(name);
 392         return ret;
 393 }
 394
 395 static void match_assign(struct expression *expr)
 396 {
 397         struct range_list *rl;
 398
 399         if (is_fake_call(expr->right))
 400                 return;
 401         if (handle_get_user(expr))
 402                 return;
 403         if (points_to_user_data(expr->right))
 404                 set_points_to_user_data(expr->left);
 405         if (handle_struct_assignment(expr))
 406                 return;
 407
 408         if (!get_user_rl(expr->right, &rl))
 409                 goto clear_old_state;
 410
 411         rl = cast_rl(get_type(expr->left), rl);
 412         set_state_expr(my_id, expr->left, alloc_estate_rl(rl));
 413
 414         return;
 415
 416 clear_old_state:
 417         if (get_state_expr(my_id, expr->left))
 418                 set_state_expr(my_id, expr->left, alloc_estate_empty());
 419 }
 420
 421 static void handle_eq_noteq(struct expression *expr)
 422 {
 423         struct smatch_state *left_orig, *right_orig;
 424
 425         left_orig = get_state_expr(my_id, expr->left);
 426         right_orig = get_state_expr(my_id, expr->right);
 427
 428         if (!left_orig && !right_orig)
 429                 return;
 430         if (left_orig && right_orig)
 431                 return;
 432
 433         if (left_orig) {
 434                 set_true_false_states_expr(my_id, expr->left,
 435                                 expr->op == SPECIAL_EQUAL ? alloc_estate_empty() : NULL,
 436                                 expr->op == SPECIAL_EQUAL ? NULL : alloc_estate_empty());
 437         } else {
 438                 set_true_false_states_expr(my_id, expr->right,
 439                                 expr->op == SPECIAL_EQUAL ? alloc_estate_empty() : NULL,
 440                                 expr->op == SPECIAL_EQUAL ? NULL : alloc_estate_empty());
 441         }
 442 }
 443
 444 static void handle_unsigned_lt_gt(struct expression *expr)
 445 {
 446         struct symbol *type;
 447         struct range_list *left;
 448         struct range_list *right;
 449         struct range_list *non_negative;
 450         sval_t min, minus_one;
 451
 452         /*
 453          * conditions are mostly handled by smatch_extra.c.  The special case
 454          * here is that say you have if (user_int < unknown_u32) {
 455          * In Smatch extra we say that, We have no idea what value
 456          * unknown_u32 is so the only thin we can say for sure is that
 457          * user_int is not -1 (UINT_MAX).  But in check_user_data2.c we should
 458          * assume that unless unknown_u32 is user data, it's probably less than
 459          * INT_MAX.
 460          *
 461          */
 462
 463         type = get_type(expr);
 464         if (!type_unsigned(type))
 465                 return;
 466
 467         /*
 468          * Assume if (user < trusted) { ... because I am lazy and because this
 469          * is the correct way to write code.
 470          */
 471         if (!get_user_rl(expr->left, &left))
 472                 return;
 473         if (get_user_rl(expr->right, &right))
 474                 return;
 475
 476         if (!sval_is_negative(rl_min(left)))
 477                 return;
 478         min = rl_min(left);
 479         minus_one.type = rl_type(left);
 480         minus_one.value = -1;
 481         non_negative = remove_range(left, min, minus_one);
 482
 483         switch (expr->op) {
 484         case '<':
 485         case SPECIAL_UNSIGNED_LT:
 486         case SPECIAL_LTE:
 487         case SPECIAL_UNSIGNED_LTE:
 488                 set_true_false_states_expr(my_id, expr->left,
 489                                            alloc_estate_rl(non_negative), NULL);
 490                 break;
 491         case '>':
 492         case SPECIAL_UNSIGNED_GT:
 493         case SPECIAL_GTE:
 494         case SPECIAL_UNSIGNED_GTE:
 495                 set_true_false_states_expr(my_id, expr->left,
 496                                            NULL, alloc_estate_rl(non_negative));
 497                 break;
 498         }
 499 }
 500
 501 static void match_condition(struct expression *expr)
 502 {
 503         if (expr->type != EXPR_COMPARE)
 504                 return;
 505
 506         if (expr->op == SPECIAL_EQUAL ||
 507             expr->op == SPECIAL_NOTEQUAL) {
 508                 handle_eq_noteq(expr);
 509                 return;
 510         }
 511
 512         handle_unsigned_lt_gt(expr);
 513 }
 514
 515 static void match_user_assign_function(const char *fn, struct expression *expr, void *unused)
 516 {
 517         func_gets_user_data = true;
 518
 519         tag_as_user_data(expr->left);
 520         set_points_to_user_data(expr->left);
 521 }
 522
 523 static void match_simple_strtoul(const char *fn, struct expression *expr, void *unused)
 524 {
 525         func_gets_user_data = true;
 526
 527         set_state_expr(my_id, expr->left, alloc_estate_whole(get_type(expr->left)));
 528 }
 529
 530 static int get_user_macro_rl(struct expression *expr, struct range_list **rl)
 531 {
 532         char *macro;
 533
 534         if (!expr)
 535                 return 0;
 536         macro = get_macro_name(expr->pos);
 537
 538         if (!macro)
 539                 return 0;
 540
 541         if (strcmp(macro, "ntohl") == 0) {
 542                 *rl = alloc_whole_rl(&uint_ctype);
 543                 return 1;
 544         }
 545         if (strcmp(macro, "ntohs") == 0) {
 546                 *rl = alloc_whole_rl(&ushort_ctype);
 547                 return 1;
 548         }
 549         return 0;
 550 }
 551
 552 struct db_info {
 553         struct range_list *rl;
 554         struct expression *call;
 555 };
 556 static int returned_rl_callback(void *_info, int argc, char **argv, char **azColName)
 557 {
 558         struct db_info *db_info = _info;
 559         struct range_list *rl;
 560         char *return_ranges = argv[0];
 561         char *user_ranges = argv[1];
 562         struct expression *arg;
 563         int comparison;
 564
 565         if (argc != 2)
 566                 return 0;
 567
 568         call_results_to_rl(db_info->call, get_type(db_info->call), user_ranges, &rl);
 569         if (str_to_comparison_arg(return_ranges, db_info->call, &comparison, &arg) &&
 570             comparison == SPECIAL_EQUAL) {
 571                 struct range_list *orig_rl;
 572
 573                 if (!get_user_rl(arg, &orig_rl))
 574                         return 0;
 575                 rl = rl_intersection(rl, orig_rl);
 576                 if (!rl)
 577                         return 0;
 578         }
 579         db_info->rl = rl_union(db_info->rl, rl);
 580
 581         return 0;
 582 }
 583
 584 static int has_user_data(struct symbol *sym)
 585 {
 586         struct sm_state *tmp;
 587
 588         FOR_EACH_MY_SM(my_id, __get_cur_stree(), tmp) {
 589                 if (tmp->sym == sym)
 590                         return 1;
 591         } END_FOR_EACH_SM(tmp);
 592         return 0;
 593 }
 594
 595 static int we_pass_user_data(struct expression *call)
 596 {
 597         struct expression *arg;
 598         struct symbol *sym;
 599
 600         FOR_EACH_PTR(call->args, arg) {
 601                 sym = expr_to_sym(arg);
 602                 if (!sym)
 603                         continue;
 604                 if (has_user_data(sym))
 605                         return 1;
 606         } END_FOR_EACH_PTR(arg);
 607
 608         return 0;
 609 }
 610
 611 static int db_returned_user_rl(struct expression *call, struct range_list **rl)
 612 {
 613         struct db_info db_info = {};
 614
 615         /* for function pointers assume everything is used */
 616         if (call->fn->type != EXPR_SYMBOL)
 617                 return 0;
 618         if (is_fake_call(call))
 619                 return 0;
 620
 621         db_info.call = call;
 622         run_sql(&returned_rl_callback, &db_info,
 623                 "select return, value from return_states where %s and type = %d and parameter = -1 and key = '$';",
 624                 get_static_filter(call->fn->symbol), USER_DATA3_SET);
 625         if (db_info.rl) {
 626                 func_gets_user_data = true;
 627                 *rl = db_info.rl;
 628                 return 1;
 629         }
 630
 631         run_sql(&returned_rl_callback, &db_info,
 632                 "select return, value from return_states where %s and type = %d and parameter = -1 and key = '$';",
 633                 get_static_filter(call->fn->symbol), USER_DATA3);
 634         if (db_info.rl) {
 635                 if (!we_pass_user_data(call))
 636                         return 0;
 637                 *rl = db_info.rl;
 638                 return 1;
 639         }
 640
 641         return 0;
 642 }
 643
 644 static int user_data_flag;
 645 static struct range_list *var_user_rl(struct expression *expr)
 646 {
 647         struct smatch_state *state;
 648         struct range_list *rl;
 649         struct range_list *absolute_rl;
 650
 651         if (expr->type == EXPR_BINOP && expr->op == '%') {
 652                 struct range_list *left, *right;
 653
 654                 if (!get_user_rl(expr->right, &right))
 655                         return NULL;
 656                 get_absolute_rl(expr->left, &left);
 657                 rl = rl_binop(left, '%', right);
 658                 goto found;
 659         }
 660
 661         if (get_user_macro_rl(expr, &rl))
 662                 goto found;
 663
 664         if (comes_from_skb_data(expr)) {
 665                 rl = alloc_whole_rl(get_type(expr));
 666                 goto found;
 667         }
 668
 669         state = get_state_expr(my_id, expr);
 670         if (state && estate_rl(state)) {
 671                 rl = estate_rl(state);
 672                 goto found;
 673         }
 674
 675         if (expr->type == EXPR_CALL && db_returned_user_rl(expr, &rl))
 676                 goto found;
 677
 678         return NULL;
 679 found:
 680         user_data_flag = 1;
 681         absolute_rl = var_to_absolute_rl(expr);
 682         return clone_rl(rl_intersection(rl, absolute_rl));
 683 }
 684
 685 int get_user_rl(struct expression *expr, struct range_list **rl)
 686 {
 687
 688         user_data_flag = 0;
 689         custom_get_absolute_rl(expr, &var_user_rl, rl);
 690         if (!user_data_flag || !*rl) {
 691                 *rl = NULL;
 692                 return 0;
 693         }
 694         return 1;
 695 }
 696
 697 int get_user_rl_var_sym(const char *name, struct symbol *sym, struct range_list **rl)
 698 {
 699         struct smatch_state *state;
 700
 701         state = get_state(my_id, name, sym);
 702         if (state && estate_rl(state)) {
 703                 *rl = estate_rl(state);
 704                 return 1;
 705         }
 706         return 0;
 707 }
 708
 709 static void match_call_info(struct expression *expr)
 710 {
 711         struct range_list *rl;
 712         struct expression *arg;
 713         int i = 0;
 714
 715         i = -1;
 716         FOR_EACH_PTR(expr->args, arg) {
 717                 i++;
 718
 719                 if (!get_user_rl(arg, &rl))
 720                         continue;
 721
 722                 sql_insert_caller_info(expr, USER_DATA3, i, "$", show_rl(rl));
 723         } END_FOR_EACH_PTR(arg);
 724 }
 725
 726 static void struct_member_callback(struct expression *call, int param, char *printed_name, struct sm_state *sm)
 727 {
 728         struct smatch_state *state;
 729         struct range_list *rl;
 730
 731         if (strcmp(sm->state->name, "") == 0)
 732                 return;
 733
 734         state = get_state(SMATCH_EXTRA, sm->name, sm->sym);
 735         if (!state || !estate_rl(state))
 736                 rl = estate_rl(sm->state);
 737         else
 738                 rl = rl_intersection(estate_rl(sm->state), estate_rl(state));
 739
 740         sql_insert_caller_info(call, USER_DATA3, param, printed_name, show_rl(rl));
 741 }
 742
 743 static void set_param_user_data(const char *name, struct symbol *sym, char *key, char *value)
 744 {
 745         struct range_list *rl = NULL;
 746         struct smatch_state *state;
 747         struct symbol *type;
 748         char fullname[256];
 749
 750         if (strcmp(key, "*$") == 0)
 751                 snprintf(fullname, sizeof(fullname), "*%s", name);
 752         else if (strncmp(key, "$", 1) == 0)
 753                 snprintf(fullname, 256, "%s%s", name, key + 1);
 754         else
 755                 return;
 756
 757         type = get_member_type_from_key(symbol_expression(sym), key);
 758
 759         /* if the caller passes a void pointer with user data */
 760         if (strcmp(key, "*$") == 0 && type && type != &void_ctype) {
 761                 struct expression *expr = symbol_expression(sym);
 762
 763                 tag_as_user_data(expr);
 764                 set_points_to_user_data(expr);
 765                 return;
 766         }
 767         str_to_rl(type, value, &rl);
 768         state = alloc_estate_rl(rl);
 769         set_state(my_id, fullname, sym, state);
 770 }
 771
 772 static void set_called(const char *name, struct symbol *sym, char *key, char *value)
 773 {
 774         set_state(my_call_id, "this_function", NULL, &called);
 775 }
 776
 777 static void match_syscall_definition(struct symbol *sym)
 778 {
 779         struct symbol *arg;
 780         char *macro;
 781         char *name;
 782         int is_syscall = 0;
 783
 784         macro = get_macro_name(sym->pos);
 785         if (macro &&
 786             (strncmp("SYSCALL_DEFINE", macro, strlen("SYSCALL_DEFINE")) == 0 ||
 787              strncmp("COMPAT_SYSCALL_DEFINE", macro, strlen("COMPAT_SYSCALL_DEFINE")) == 0))
 788                 is_syscall = 1;
 789
 790         name = get_function();
 791         if (!option_no_db && get_state(my_call_id, "this_function", NULL) != &called) {
 792                 if (name && strncmp(name, "sys_", 4) == 0)
 793                         is_syscall = 1;
 794         }
 795
 796         if (name && strncmp(name, "compat_sys_", 11) == 0)
 797                 is_syscall = 1;
 798
 799         if (!is_syscall)
 800                 return;
 801
 802         FOR_EACH_PTR(sym->ctype.base_type->arguments, arg) {
 803                 set_state(my_id, arg->ident->name, arg, alloc_estate_whole(get_real_base_type(arg)));
 804         } END_FOR_EACH_PTR(arg);
 805 }
 806
 807 static void set_to_user_data(struct expression *expr, char *key, char *value)
 808 {
 809         char *name;
 810         struct symbol *sym;
 811         struct symbol *type;
 812         struct range_list *rl = NULL;
 813
 814         type = get_member_type_from_key(expr, key);
 815         name = get_variable_from_key(expr, key, &sym);
 816         if (!name || !sym)
 817                 goto free;
 818
 819         call_results_to_rl(expr, type, value, &rl);
 820
 821         set_state(my_id, name, sym, alloc_estate_rl(rl));
 822 free:
 823         free_string(name);
 824
 825 }
 826
 827 static void returns_param_user_data(struct expression *expr, int param, char *key, char *value)
 828 {
 829         struct expression *arg;
 830         struct expression *call;
 831
 832         call = expr;
 833         while (call->type == EXPR_ASSIGNMENT)
 834                 call = strip_expr(call->right);
 835         if (call->type != EXPR_CALL)
 836                 return;
 837
 838         if (!we_pass_user_data(call))
 839                 return;
 840
 841         if (param == -1) {
 842                 if (expr->type != EXPR_ASSIGNMENT)
 843                         return;
 844                 set_to_user_data(expr->left, key, value);
 845                 return;
 846         }
 847
 848         arg = get_argument_from_call_expr(call->args, param);
 849         if (!arg)
 850                 return;
 851         set_to_user_data(arg, key, value);
 852 }
 853
 854 static void returns_param_user_data_set(struct expression *expr, int param, char *key, char *value)
 855 {
 856         struct expression *arg;
 857
 858         func_gets_user_data = true;
 859
 860         if (param == -1) {
 861                 if (expr->type != EXPR_ASSIGNMENT)
 862                         return;
 863                 if (strcmp(key, "*$") == 0) {
 864                         set_points_to_user_data(expr->left);
 865                         tag_as_user_data(expr->left);
 866                 } else {
 867                         set_to_user_data(expr->left, key, value);
 868                 }
 869                 return;
 870         }
 871
 872         while (expr->type == EXPR_ASSIGNMENT)
 873                 expr = strip_expr(expr->right);
 874         if (expr->type != EXPR_CALL)
 875                 return;
 876
 877         arg = get_argument_from_call_expr(expr->args, param);
 878         if (!arg)
 879                 return;
 880         set_to_user_data(arg, key, value);
 881 }
 882
 883 static int has_empty_state(struct sm_state *sm)
 884 {
 885         struct sm_state *tmp;
 886
 887         FOR_EACH_PTR(sm->possible, tmp) {
 888                 if (!estate_rl(tmp->state))
 889                         return 1;
 890         } END_FOR_EACH_PTR(tmp);
 891
 892         return 0;
 893 }
 894
 895 static void param_set_to_user_data(int return_id, char *return_ranges, struct expression *expr)
 896 {
 897         struct sm_state *sm;
 898         struct smatch_state *start_state;
 899         struct range_list *rl;
 900         int param;
 901         char *return_str;
 902         const char *param_name;
 903
 904         expr = strip_expr(expr);
 905         return_str = expr_to_str(expr);
 906
 907         FOR_EACH_MY_SM(my_id, __get_cur_stree(), sm) {
 908                 if (has_empty_state(sm))
 909                         continue;
 910
 911                 param = get_param_num_from_sym(sm->sym);
 912                 if (param < 0) {
 913                         if (expr_to_sym(expr) == sm->sym)
 914                                 param = -1;
 915                         else
 916                                 continue;
 917                 }
 918
 919                 /* The logic here was that if we were passed in a user data then
 920                  * we don't record that.  It's like the difference between
 921                  * param_filter and param_set.  When I think about it, I'm not
 922                  * sure it actually works.  It's probably harmless because we
 923                  * checked earlier that we're not returning a parameter...
 924                  * Let's mark this as a TODO.
 925                  */
 926                 start_state = get_state_stree(start_states, my_id, sm->name, sm->sym);
 927                 if (start_state && rl_equiv(estate_rl(sm->state), estate_rl(start_state)))
 928                         continue;
 929
 930                 if (param == -1)
 931                         param_name = state_name_to_param_name(sm->name, return_str);
 932                 else
 933                         param_name = get_param_name(sm);
 934                 if (!param_name)
 935                         continue;
 936                 if (strcmp(param_name, "$") == 0)  /* The -1 param is handled after the loop */
 937                         continue;
 938
 939                 sql_insert_return_states(return_id, return_ranges,
 940                                          func_gets_user_data ? USER_DATA3_SET : USER_DATA3,
 941                                          param, param_name, show_rl(estate_rl(sm->state)));
 942         } END_FOR_EACH_SM(sm);
 943
 944         if (points_to_user_data(expr)) {
 945                 sql_insert_return_states(return_id, return_ranges,
 946                                          (is_skb_data(expr) || !func_gets_user_data) ?
 947                                          USER_DATA3_SET : USER_DATA3,
 948                                          -1, "*$", "");
 949         } else if (get_user_rl(expr, &rl)) {
 950                 sql_insert_return_states(return_id, return_ranges,
 951                                          func_gets_user_data ? USER_DATA3_SET : USER_DATA3,
 952                                          -1, "$", show_rl(rl));
 953         }
 954
 955         free_string(return_str);
 956 }
 957
 958 static struct int_stack *gets_data_stack;
 959 static void match_function_def(struct symbol *sym)
 960 {
 961         func_gets_user_data = false;
 962 }
 963
 964 static void match_inline_start(struct expression *expr)
 965 {
 966         push_int(&gets_data_stack, func_gets_user_data);
 967 }
 968
 969 static void match_inline_end(struct expression *expr)
 970 {
 971         func_gets_user_data = pop_int(&gets_data_stack);
 972 }
 973
 974 void check_user_data2(int id)
 975 {
 976         int i;
 977
 978         my_id = id;
 979
 980         if (option_project != PROJ_KERNEL)
 981                 return;
 982
 983         add_hook(&match_function_def, FUNC_DEF_HOOK);
 984         add_hook(&match_inline_start, INLINE_FN_START);
 985         add_hook(&match_inline_end, INLINE_FN_END);
 986
 987         add_hook(&save_start_states, AFTER_DEF_HOOK);
 988         add_hook(&free_start_states, AFTER_FUNC_HOOK);
 989         add_hook(&match_save_states, INLINE_FN_START);
 990         add_hook(&match_restore_states, INLINE_FN_END);
 991
 992         add_unmatched_state_hook(my_id, &empty_state);
 993         add_extra_nomod_hook(&extra_nomod_hook);
 994         add_pre_merge_hook(my_id, &pre_merge_hook);
 995         add_merge_hook(my_id, &merge_estates);
 996
 997         add_function_hook("copy_from_user", &match_user_copy, INT_PTR(0));
 998         add_function_hook("__copy_from_user", &match_user_copy, INT_PTR(0));
 999         add_function_hook("memcpy_fromiovec", &match_user_copy, INT_PTR(0));
1000         for (i = 0; i < ARRAY_SIZE(kstr_funcs); i++)
1001                 add_function_hook(kstr_funcs[i], &match_user_copy, INT_PTR(2));
1002
1003         add_function_assign_hook("simple_strtol", &match_simple_strtoul, NULL);
1004         add_function_assign_hook("simple_strtoll", &match_simple_strtoul, NULL);
1005         add_function_assign_hook("simple_strtoul", &match_simple_strtoul, NULL);
1006         add_function_assign_hook("simple_strtoull", &match_simple_strtoul, NULL);
1007
1008         add_function_hook("sscanf", &match_sscanf, NULL);
1009
1010         add_function_assign_hook("memdup_user", &match_user_assign_function, NULL);
1011         add_function_assign_hook("kmap_atomic", &match_user_assign_function, NULL);
1012         add_function_assign_hook("skb_network_header", &match_user_assign_function, NULL);
1013
1014         add_hook(&match_syscall_definition, AFTER_DEF_HOOK);
1015
1016         add_hook(&match_assign, ASSIGNMENT_HOOK);
1017         add_hook(&match_condition, CONDITION_HOOK);
1018
1019         add_hook(&match_call_info, FUNCTION_CALL_HOOK);
1020         add_member_info_callback(my_id, struct_member_callback);
1021         select_caller_info_hook(set_param_user_data, USER_DATA3);
1022         select_return_states_hook(USER_DATA3, &returns_param_user_data);
1023         select_return_states_hook(USER_DATA3_SET, &returns_param_user_data_set);
1024         add_split_return_callback(&param_set_to_user_data);
1025 }
1026
1027 void check_user_data3(int id)
1028 {
1029         my_call_id = id;
1030
1031         if (option_project != PROJ_KERNEL)
1032                 return;
1033         select_caller_info_hook(set_called, INTERNAL);
1034 }
1035