check_syscall_arg_type.c

   1 /*
   2  * Copyright (C) 2017 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 /*
  19  * This is to help create Trinity fuzzer templates.
  20  *
  21  */
  22
  23 #include "smatch.h"
  24 #include "smatch_slist.h"
  25
  26 static int my_id;
  27
  28 STATE(ARG_FD);
  29 #if 0
  30 STATE(arg_range);
  31 STATE(arg_op);
  32 STATE(arg_list);
  33 STATE(arg_cpu);
  34 STATE(arg_pathname);
  35 #endif
  36 // nr_segs * sizeof(struct iovec)
  37 // if (nr_segs > UIO_MAXIOV)
  38 #if 0
  39 STATE(arg_ioveclen);
  40 STATE(arg_sockaddrlen);
  41 STATE(arg_socketinfo);
  42 #endif
  43
  44 struct smatch_state *merge_states(struct smatch_state *s1, struct smatch_state *s2)
  45 {
  46         if (s1 == &undefined)
  47                 return s2;
  48         return s1;
  49 }
  50
  51 struct typedef_lookup {
  52         const char *name;
  53         struct symbol *sym;
  54         int failed;
  55 };
  56
  57 static struct symbol *_typedef_lookup(const char *name)
  58 {
  59         struct ident *id;
  60         struct symbol *node;
  61
  62         id = built_in_ident(name);
  63         if (!id)
  64                 return NULL;
  65         node = lookup_symbol(id, NS_TYPEDEF);
  66         if (!node || node->type != SYM_NODE)
  67                 return NULL;
  68         return get_real_base_type(node);
  69 }
  70
  71 static void typedef_lookup(struct typedef_lookup *tl)
  72 {
  73         if (tl->sym || tl->failed)
  74                 return;
  75         tl->sym = _typedef_lookup(tl->name);
  76         if (!tl->sym)
  77                 tl->failed = 1;
  78 }
  79
  80 static int is_mode_t(struct symbol *sym)
  81 {
  82         static struct typedef_lookup umode_t = { .name = "umode_t" };
  83         struct symbol *type;
  84
  85         typedef_lookup(&umode_t);
  86         if (!umode_t.sym)
  87                 return 0;
  88         type = get_base_type(sym);
  89         if (type == umode_t.sym)
  90                 return 1;
  91         return 0;
  92 }
  93
  94 static int is_pid_t(struct symbol *sym)
  95 {
  96         static struct typedef_lookup pid_t = { .name = "pid_t" };
  97         struct symbol *type;
  98
  99         typedef_lookup(&pid_t);
 100         if (!pid_t.sym)
 101                 return 0;
 102         type = get_base_type(sym);
 103         if (type == pid_t.sym)
 104                 return 1;
 105         return 0;
 106 }
 107
 108 static const char *get_arg_type_from_type(struct symbol *sym)
 109 {
 110         struct symbol *type;
 111
 112         if (is_mode_t(sym))
 113                 return "ARG_MODE_T";
 114         if (is_pid_t(sym))
 115                 return "ARG_PID";
 116
 117         type = get_real_base_type(sym);
 118         if (!type || type->type != SYM_PTR)
 119                 return NULL;
 120         type = get_real_base_type(type);
 121         if (!type)
 122                 return NULL;
 123         if (type == &char_ctype)
 124                 return "ARG_MMAP";
 125         if (!type->ident)
 126                 return NULL;
 127         if (strcmp(type->ident->name, "iovec") == 0)
 128                 return "ARG_IOVEC";
 129         if (strcmp(type->ident->name, "sockaddr") == 0)
 130                 return "ARG_SOCKADDR";
 131         return "ARG_ADDRESS";
 132 }
 133
 134 static void match_fdget(const char *fn, struct expression *expr, void *unused)
 135 {
 136         struct expression *arg;
 137
 138         arg = get_argument_from_call_expr(expr->args, 0);
 139         set_state_expr(my_id, arg, &ARG_FD);
 140 }
 141
 142 const char *get_syscall_arg_type(struct symbol *sym)
 143 {
 144         struct smatch_state *state;
 145         const char *type;
 146
 147         if (!sym || !sym->ident)
 148                 return "ARG_UNDEFINED";
 149         type = get_arg_type_from_type(sym);
 150         if (type)
 151                 return type;
 152         state = get_state(my_id, sym->ident->name, sym);
 153         if (!state)
 154                 return "ARG_UNDEFINED";
 155         return state->name;
 156 }
 157
 158 void check_syscall_arg_type(int id)
 159 {
 160         my_id = id;
 161         if (option_project != PROJ_KERNEL)
 162                 return;
 163
 164         add_merge_hook(my_id, &merge_states);
 165         add_function_hook("fdget", &match_fdget, NULL);
 166 }
 167
 168