check_deref_check.c

   1 /*
   2  * Copyright (C) 2009 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 #include "smatch.h"
  19 #include "smatch_slist.h"
  20 #include "smatch_extra.h"
  21
  22 static int my_id;
  23
  24 STATE(derefed);
  25
  26 static void deref_hook(struct expression *expr)
  27 {
  28         if (implied_not_equal(expr, 0))
  29                 return;
  30         if (is_impossible_path())
  31                 return;
  32         set_state_expr(my_id, expr, &derefed);
  33 }
  34
  35 static void match_condition(struct expression *expr)
  36 {
  37         struct sm_state *sm;
  38         char *name;
  39
  40         if (__in_pre_condition)
  41                 return;
  42
  43         name = get_macro_name(expr->pos);
  44         if (name &&
  45             (strcmp(name, "likely") != 0 && strcmp(name, "unlikely") != 0))
  46                 return;
  47
  48         if (!is_pointer(expr))
  49                 return;
  50
  51         sm = get_sm_state_expr(my_id, expr);
  52         if (!sm || sm->state != &derefed)
  53                 return;
  54
  55         sm_warning("variable dereferenced before check '%s' (see line %d)", sm->name, sm->line);
  56         set_state_expr(my_id, expr, &undefined);
  57 }
  58
  59 static void match_err_check(struct expression *expr, const char *name, struct symbol *sym, void *data)
  60 {
  61         struct sm_state *sm;
  62         char *macro;
  63
  64         if (__in_pre_condition)
  65                 return;
  66
  67         sm = get_sm_state(my_id, name, sym);
  68         if (!sm || sm->state != &derefed)
  69                 return;
  70
  71         macro = get_macro_name(expr->pos);
  72         if (macro && strcmp(macro, "gvt_vgpu_err") == 0)
  73                 return;
  74
  75         sm_warning("variable dereferenced before IS_ERR check '%s' (see line %d)", sm->name, sm->line);
  76         set_state_expr(my_id, expr, &undefined);
  77 }
  78
  79 void check_deref_check(int id)
  80 {
  81         my_id = id;
  82
  83         add_dereference_hook(deref_hook);
  84         add_modification_hook(my_id, &set_undefined);
  85
  86         add_hook(&match_condition, CONDITION_HOOK);
  87
  88         add_function_param_key_hook("IS_ERR", &match_err_check, 0, "$", NULL);
  89         add_function_param_key_hook("PTR_ERR_OR_ZERO", &match_err_check, 0, "$", NULL);
  90         add_function_param_key_hook("IS_ERR_OR_NULL", &match_err_check, 0, "$", NULL);
  91 }