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 underef(struct sm_state *sm, struct expression *mod_expr)
  27 {
  28         set_state(my_id, sm->name, sm->sym, &undefined);
  29 }
  30
  31 static void deref_hook(struct expression *expr)
  32 {
  33         if (implied_not_equal(expr, 0))
  34                 return;
  35         if (is_impossible_path())
  36                 return;
  37         set_state_expr(my_id, expr, &derefed);
  38 }
  39
  40 static void match_condition(struct expression *expr)
  41 {
  42         struct sm_state *sm;
  43         char *name;
  44
  45         if (__in_pre_condition)
  46                 return;
  47
  48         name = get_macro_name(expr->pos);
  49         if (name &&
  50             (strcmp(name, "likely") != 0 && strcmp(name, "unlikely") != 0))
  51                 return;
  52
  53         if (!is_pointer(expr))
  54                 return;
  55
  56         sm = get_sm_state_expr(my_id, expr);
  57         if (!sm || sm->state != &derefed)
  58                 return;
  59
  60         sm_warning("variable dereferenced before check '%s' (see line %d)", sm->name, sm->line);
  61         set_state_expr(my_id, expr, &undefined);
  62 }
  63
  64 static void match_err_check(struct expression *expr, const char *name, struct symbol *sym, void *data)
  65 {
  66         struct sm_state *sm;
  67         char *macro;
  68
  69         if (__in_pre_condition)
  70                 return;
  71
  72         sm = get_sm_state(my_id, name, sym);
  73         if (!sm || sm->state != &derefed)
  74                 return;
  75
  76         macro = get_macro_name(expr->pos);
  77         if (macro && strcmp(macro, "gvt_vgpu_err") == 0)
  78                 return;
  79
  80         sm_warning("variable dereferenced before IS_ERR check '%s' (see line %d)", sm->name, sm->line);
  81         set_state_expr(my_id, expr, &undefined);
  82 }
  83
  84 void check_deref_check(int id)
  85 {
  86         my_id = id;
  87
  88         add_dereference_hook(deref_hook);
  89         add_modification_hook(my_id, &underef);
  90
  91         add_hook(&match_condition, CONDITION_HOOK);
  92
  93         add_function_param_key_hook("IS_ERR", &match_err_check, 0, "$", NULL);
  94         add_function_param_key_hook("PTR_ERR_OR_ZERO", &match_err_check, 0, "$", NULL);
  95         add_function_param_key_hook("IS_ERR_OR_NULL", &match_err_check, 0, "$", NULL);
  96 }