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