check_unwind.c

   1 /*
   2  * Copyright (C) 2020 Oracle.
   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 #include <ctype.h>
  19
  20 #include "smatch.h"
  21 #include "smatch_extra.h"
  22 #include "smatch_slist.h"
  23
  24 static int my_id;
  25 static int info_id;
  26
  27 STATE(alloc);
  28 STATE(release);
  29 STATE(param_released);
  30 STATE(ignore);
  31
  32 static unsigned long fn_has_alloc;
  33
  34 struct ref_func_info {
  35         const char *name;
  36         int type;
  37         int param;
  38         const char *key;
  39         const sval_t *implies_start, *implies_end;
  40         func_hook *call_back;
  41 };
  42
  43 static struct ref_func_info func_table[] = {
  44         { "clk_prepare", ALLOC, 0, "$", &int_zero, &int_zero },
  45         { "clk_prepare_enable", ALLOC, 0, "$", &int_zero, &int_zero },
  46         { "clk_disable_unprepare", RELEASE, 0, "$" },
  47         { "clk_unprepare", RELEASE, 0, "$" },
  48
  49         { "alloc_etherdev_mqs", ALLOC, -1, "$", &valid_ptr_min_sval, &valid_ptr_max_sval },
  50         { "free_netdev", RELEASE, 0, "$" },
  51
  52         /*
  53          * FIXME: A common pattern in release functions like amd76xrom_cleanup()
  54          * is to do:
  55          *
  56          *      if (window->rsrc.parent)
  57          *              release_resource(&window->rsrc);
  58          *
  59          * Which is slightly tricky to know how to merge the states so let's
  60          * hold off checking request_resource() for now.
  61          *
  62          * { "request_resource", ALLOC,   1, "$", &int_zero, &int_zero },
  63          * { "release_resource", RELEASE, 0, "$" },
  64          *
  65          */
  66
  67         { "pci_request_regions", ALLOC,   0, "$", &int_zero, &int_zero },
  68         { "pci_release_regions", RELEASE, 0, "$" },
  69
  70         { "request_free_mem_region", ALLOC,   -1, "$->start", &valid_ptr_min_sval, &valid_ptr_max_sval },
  71         { "__request_region", ALLOC,   1, "$", &valid_ptr_min_sval, &valid_ptr_max_sval },
  72         { "release_and_free_resource", RELEASE, 0, "$->start" },
  73         { "release_resource", RELEASE, 0, "$->start" },
  74         { "__release_region", RELEASE, 1, "$" },
  75
  76         { "ioremap", ALLOC,  -1, "$", &valid_ptr_min_sval, &valid_ptr_max_sval },
  77         { "of_iomap", ALLOC,  -1, "$", &valid_ptr_min_sval, &valid_ptr_max_sval },
  78         { "ioremap_encrypted", ALLOC,  -1, "$", &valid_ptr_min_sval, &valid_ptr_max_sval },
  79         { "iounmap", RELEASE, 0, "$" },
  80
  81         { "request_threaded_irq", ALLOC,   0, "$", &int_zero, &int_zero },
  82         { "request_irq", ALLOC,   0, "$", &int_zero, &int_zero },
  83         { "free_irq",    RELEASE, 0, "$" },
  84         { "pci_request_irq", ALLOC,   1, "$", &int_zero, &int_zero },
  85         { "pci_free_irq",    RELEASE, 1, "$" },
  86
  87         { "register_netdev",   ALLOC,   0, "$", &int_zero, &int_zero },
  88         { "unregister_netdev", RELEASE, 0, "$" },
  89
  90         { "misc_register",   ALLOC,   0, "$", &int_zero, &int_zero },
  91         { "misc_deregister", RELEASE, 0, "$" },
  92
  93         { "ieee80211_alloc_hw", ALLOC,  -1, "$", &valid_ptr_min_sval, &valid_ptr_max_sval },
  94         { "ieee80211_free_hw",  RELEASE, 0, "$" },
  95 };
  96
  97 static struct smatch_state *unmatched_state(struct sm_state *sm)
  98 {
  99         struct smatch_state *state;
 100
 101         if (sm->state != &param_released)
 102                 return &undefined;
 103
 104         if (is_impossible_path())
 105                 return &param_released;
 106
 107         state = get_state(SMATCH_EXTRA, sm->name, sm->sym);
 108         if (!state)
 109                 return &undefined;
 110         if (!estate_rl(state) || is_err_or_null(estate_rl(state)))
 111                 return &param_released;
 112         if (parent_is_err_or_null_var_sym(sm->name, sm->sym))
 113                 return &param_released;
 114
 115          return &undefined;
 116 }
 117
 118 static bool is_param_var_sym(const char *name, struct symbol *sym)
 119 {
 120         const char *key;
 121
 122         return get_param_key_from_var_sym(name, sym, NULL, &key) >= 0;
 123 }
 124
 125 static void mark_matches_as_undefined(const char *key)
 126 {
 127         struct sm_state *sm;
 128         int start_pos, state_len, key_len;
 129         char *p;
 130
 131         while ((p = strchr(key, '-'))) {
 132                 if (p[1] != '>')
 133                         return;
 134                 key = p + 2;
 135         }
 136         key_len = strlen(key);
 137
 138         FOR_EACH_MY_SM(my_id, __get_cur_stree(), sm) {
 139                 state_len = strlen(sm->name);
 140                 if (state_len < key_len)
 141                         continue;
 142                 if (!slist_has_state(sm->possible, &alloc))
 143                         continue;
 144
 145                 start_pos = state_len - key_len;
 146                 if ((start_pos == 0 || !isalnum(sm->name[start_pos - 1])) &&
 147                     strcmp(sm->name + start_pos, key) == 0)
 148                         update_ssa_state(my_id, sm->name, sm->sym, &undefined);
 149
 150         } END_FOR_EACH_SM(sm);
 151 }
 152
 153 static bool is_alloc_primitive(struct expression *expr)
 154 {
 155         int i;
 156
 157         while (expr->type == EXPR_ASSIGNMENT)
 158                 expr = strip_expr(expr->right);
 159         if (expr->type != EXPR_CALL)
 160                 return false;
 161
 162         if (expr->fn->type != EXPR_SYMBOL)
 163                 return false;
 164
 165         for (i = 0; i < ARRAY_SIZE(func_table); i++) {
 166                 if (sym_name_is(func_table[i].name, expr->fn))
 167                         return true;
 168         }
 169
 170         return false;
 171 }
 172
 173 static void return_param_alloc(struct expression *expr, const char *name, struct symbol *sym, void *data)
 174 {
 175         fn_has_alloc = true;
 176         set_ssa_state(my_id, name, sym, &alloc);
 177 }
 178
 179 static void return_param_release(struct expression *expr, const char *name, struct symbol *sym, void *data)
 180 {
 181         struct sm_state *start_sm;
 182
 183         /* The !data means this comes from the DB (not hard coded). */
 184         if (!data && is_alloc_primitive(expr))
 185                 return;
 186
 187         start_sm = get_ssa_sm_state(my_id, name, sym);
 188         if (start_sm) {
 189                 update_ssa_state(my_id, start_sm->name, start_sm->sym, &release);
 190         } else {
 191                 if (fn_has_alloc) {
 192                         mark_matches_as_undefined(name);
 193                         return;
 194                 }
 195                 if (is_param_var_sym(name, sym))
 196                         set_state(info_id, name, sym, &param_released);
 197         }
 198 }
 199
 200 static void ignore_path(const char *fn, struct expression *expr, void *data)
 201 {
 202         set_state(my_id, "path", NULL, &ignore);
 203 }
 204
 205 static void match_return_info(int return_id, char *return_ranges, struct expression *expr)
 206 {
 207         struct sm_state *sm;
 208         const char *param_name;
 209         int param;
 210
 211         if (is_impossible_path())
 212                 return;
 213
 214         FOR_EACH_MY_SM(info_id, __get_cur_stree(), sm) {
 215                 if (sm->state != &param_released)
 216                         continue;
 217                 param = get_param_key_from_sm(sm, expr, &param_name);
 218                 if (param < 0)
 219                         continue;
 220                 sql_insert_return_states(return_id, return_ranges, RELEASE,
 221                                          param, param_name, "");
 222         } END_FOR_EACH_SM(sm);
 223 }
 224
 225 enum {
 226         UNKNOWN, FAIL, SUCCESS, NUM_BUCKETS
 227 };
 228
 229 static int success_fail_positive(struct range_list *rl)
 230 {
 231         if (!rl)
 232                 return UNKNOWN;
 233
 234         if (sval_is_negative(rl_min(rl)) && sval_is_negative(rl_max(rl)))
 235                 return FAIL;
 236
 237         if (rl_min(rl).value == 0)
 238                 return SUCCESS;
 239
 240         return UNKNOWN;
 241 }
 242
 243 static void check_balance(const char *name, struct symbol *sym)
 244 {
 245         struct range_list *inc_lines = NULL;
 246         int inc_buckets[NUM_BUCKETS] = {};
 247         struct stree *stree, *orig_stree;
 248         struct smatch_state *state;
 249         struct sm_state *return_sm;
 250         struct sm_state *sm;
 251         sval_t line = sval_type_val(&int_ctype, 0);
 252         int bucket;
 253
 254         FOR_EACH_PTR(get_all_return_strees(), stree) {
 255                 orig_stree = __swap_cur_stree(stree);
 256
 257                 if (is_impossible_path())
 258                         goto swap_stree;
 259                 if (db_incomplete())
 260                         goto swap_stree;
 261                 if (get_state(my_id, "path", NULL) == &ignore)
 262                         goto swap_stree;
 263
 264                 return_sm = get_sm_state(RETURN_ID, "return_ranges", NULL);
 265                 if (!return_sm)
 266                         goto swap_stree;
 267                 line.value = return_sm->line;
 268
 269                 sm = get_sm_state(my_id, name, sym);
 270                 if (!sm)
 271                         goto swap_stree;
 272
 273                 state = sm->state;
 274                 if (state == &param_released)
 275                         state = &release;
 276
 277                 if (state != &alloc &&
 278                     state != &release)
 279                         goto swap_stree;
 280
 281                 bucket = success_fail_positive(estate_rl(return_sm->state));
 282                 if (bucket != FAIL)
 283                         goto swap_stree;
 284
 285                 if (state == &alloc) {
 286                         add_range(&inc_lines, line, line);
 287                         inc_buckets[bucket] = true;
 288                 }
 289 swap_stree:
 290                 __swap_cur_stree(orig_stree);
 291         } END_FOR_EACH_PTR(stree);
 292
 293         if (inc_buckets[FAIL])
 294                 goto complain;
 295
 296         return;
 297
 298 complain:
 299         sm_warning("'%s' not released on lines: %s.", ssa_name(name), show_rl(inc_lines));
 300 }
 301
 302 static void match_check_balanced(struct symbol *sym)
 303 {
 304         struct sm_state *sm;
 305
 306         FOR_EACH_MY_SM(my_id, get_all_return_states(), sm) {
 307                 if (sm->sym == NULL && strcmp(sm->name, "path") == 0)
 308                         continue;
 309                 check_balance(sm->name, sm->sym);
 310         } END_FOR_EACH_SM(sm);
 311 }
 312
 313 void check_unwind(int id)
 314 {
 315         struct ref_func_info *info;
 316         int i;
 317
 318         my_id = id;
 319
 320         if (option_project != PROJ_KERNEL)
 321                 return;
 322
 323         for (i = 0; i < ARRAY_SIZE(func_table); i++) {
 324                 info = &func_table[i];
 325
 326                 if (info->call_back) {
 327                         add_function_hook(info->name, info->call_back, info);
 328                 } else if (info->implies_start && info->type == ALLOC) {
 329                         return_implies_param_key_exact(info->name,
 330                                         *info->implies_start,
 331                                         *info->implies_end,
 332                                         &return_param_alloc,
 333                                         info->param, info->key, info);
 334                 } else if (info->implies_start) {
 335                         return_implies_param_key(info->name,
 336                                         *info->implies_start,
 337                                         *info->implies_end,
 338                                         &return_param_release,
 339                                         info->param, info->key, info);
 340                 } else {
 341                         add_function_param_key_hook(info->name,
 342                                 (info->type == ALLOC) ? &return_param_alloc : &return_param_release,
 343                                 info->param, info->key, info);
 344                 }
 345         }
 346
 347         add_function_hook("devm_add_action_or_reset", &ignore_path, NULL);
 348         add_function_hook("drmm_add_action", &ignore_path, NULL);
 349         add_function_hook("__drmm_add_action", &ignore_path, NULL);
 350
 351         add_function_data(&fn_has_alloc);
 352
 353         add_split_return_callback(match_return_info);
 354         select_return_param_key(RELEASE, &return_param_release);
 355         add_hook(&match_check_balanced, END_FUNC_HOOK);
 356 }
 357
 358 void check_unwind_info(int id)
 359 {
 360         info_id = id;
 361         add_unmatched_state_hook(info_id, &unmatched_state);
 362 }