2 * smatch/check_user_data.c
4 * Copyright (C) 2011 Dan Carpenter.
6 * Licensed under the Open Software License version 1.1
11 * There are a couple checks that try to see if a variable
12 * comes from the user. It would be better to unify them
13 * into one place. Also it we should follow the data down
14 * the call paths. Hence this file.
18 #include "smatch_slist.h"
19 #include "smatch_extra.h"
26 static int is_user_macro(struct expression
*expr
)
31 static int db_user_data
;
32 static int db_user_data_callback(void *unused
, int argc
, char **argv
, char **azColName
)
38 static int passes_user_data(struct expression
*expr
)
40 struct expression
*arg
;
42 FOR_EACH_PTR(expr
->args
, arg
) {
43 if (is_user_data(arg
))
45 } END_FOR_EACH_PTR(arg
);
50 static int is_user_fn_db(struct expression
*expr
)
53 static char sql_filter
[1024];
55 if (expr
->fn
->type
!= EXPR_SYMBOL
)
57 sym
= expr
->fn
->symbol
;
61 if (!passes_user_data(expr
))
64 if (sym
->ctype
.modifiers
& MOD_STATIC
) {
65 snprintf(sql_filter
, 1024, "file = '%s' and function = '%s';",
66 get_filename(), sym
->ident
->name
);
68 snprintf(sql_filter
, 1024, "function = '%s' and static = 0;",
73 run_sql(db_user_data_callback
, "select value from return_states where type=%d and %s",
74 USER_DATA
, sql_filter
);
78 static int is_user_function(struct expression
*expr
)
80 if (expr
->type
!= EXPR_CALL
)
82 if (sym_name_is("kmemdup_user", expr
->fn
))
84 return is_user_fn_db(expr
);
87 static int is_skb_data(struct expression
*expr
)
94 name
= expr_to_var_sym(expr
, &sym
);
98 sym
= get_base_type(sym
);
99 if (!sym
|| sym
->type
!= SYM_PTR
)
101 sym
= get_base_type(sym
);
102 if (!sym
|| sym
->type
!= SYM_STRUCT
|| !sym
->ident
)
104 if (strcmp(sym
->ident
->name
, "sk_buff") != 0)
110 if (strcmp(name
+ len
- 6, "->data") == 0)
118 static int in_container_of_macro(struct expression
*expr
)
122 macro
= get_macro_name(expr
->pos
);
126 if (strcmp(macro
, "container_of") == 0)
131 int is_user_data(struct expression
*expr
)
133 struct state_list
*slist
= NULL
;
134 struct sm_state
*tmp
;
144 if (in_container_of_macro(expr
))
147 if (is_user_macro(expr
))
149 if (is_user_function(expr
))
151 if (is_skb_data(expr
))
154 expr
= strip_expr(expr
); /* this has to come after is_user_macro() */
156 if (expr
->type
== EXPR_BINOP
) {
157 if (is_user_data(expr
->left
))
159 if (is_user_data(expr
->right
))
163 if (expr
->type
== EXPR_PREOP
&& (expr
->op
== '&' || expr
->op
== '*'))
164 expr
= strip_expr(expr
->unop
);
166 tmp
= get_sm_state_expr(my_id
, expr
);
168 return slist_has_state(tmp
->possible
, &user_data
);
170 name
= expr_to_str_sym(expr
, &sym
);
174 slist
= get_all_states(my_id
);
175 FOR_EACH_PTR(slist
, tmp
) {
178 if (!strncmp(tmp
->name
, name
, strlen(tmp
->name
))) {
179 if (slist_has_state(tmp
->possible
, &user_data
))
183 } END_FOR_EACH_PTR(tmp
);
191 void set_param_user_data(const char *name
, struct symbol
*sym
, char *key
, char *value
)
195 if (strncmp(key
, "$$", 2))
197 snprintf(fullname
, 256, "%s%s", name
, key
+ 2);
198 set_state(my_id
, fullname
, sym
, &user_data
);
201 static void match_syscall_definition(struct symbol
*sym
)
206 macro
= get_macro_name(sym
->pos
);
209 if (strncmp("SYSCALL_DEFINE", macro
, strlen("SYSCALL_DEFINE")))
212 FOR_EACH_PTR(sym
->ctype
.base_type
->arguments
, arg
) {
213 set_state(my_id
, arg
->ident
->name
, arg
, &user_data
);
214 } END_FOR_EACH_PTR(arg
);
217 static void match_condition(struct expression
*expr
)
222 case SPECIAL_UNSIGNED_LT
:
223 case SPECIAL_UNSIGNED_LTE
:
224 if (is_user_data(expr
->left
))
225 set_true_false_states_expr(my_id
, expr
->left
, &capped
, NULL
);
226 if (is_user_data(expr
->right
))
227 set_true_false_states_expr(my_id
, expr
->right
, NULL
, &capped
);
231 case SPECIAL_UNSIGNED_GT
:
232 case SPECIAL_UNSIGNED_GTE
:
233 if (is_user_data(expr
->right
))
234 set_true_false_states_expr(my_id
, expr
->right
, &capped
, NULL
);
235 if (is_user_data(expr
->left
))
236 set_true_false_states_expr(my_id
, expr
->left
, NULL
, &capped
);
239 if (is_user_data(expr
->left
))
240 set_true_false_states_expr(my_id
, expr
->left
, &capped
, NULL
);
241 if (is_user_data(expr
->right
))
242 set_true_false_states_expr(my_id
, expr
->right
, &capped
, NULL
);
244 case SPECIAL_NOTEQUAL
:
245 if (is_user_data(expr
->left
))
246 set_true_false_states_expr(my_id
, expr
->left
, NULL
, &capped
);
247 if (is_user_data(expr
->right
))
248 set_true_false_states_expr(my_id
, expr
->right
, NULL
, &capped
);
255 static void match_normal_assign(struct expression
*expr
)
257 if (is_user_data(expr
->right
))
258 set_state_expr(my_id
, expr
->left
, &user_data
);
261 if (is_user_data(expr
->left
))
262 set_state_expr(my_id
, expr
->left
, &capped
);
265 static void match_assign(struct expression
*expr
)
269 name
= get_macro_name(expr
->pos
);
270 if (!name
|| strcmp(name
, "get_user") != 0) {
271 match_normal_assign(expr
);
274 name
= expr_to_var(expr
->right
);
275 if (!name
|| strcmp(name
, "__val_gu") != 0)
277 set_state_expr(my_id
, expr
->left
, &user_data
);
282 static void match_user_copy(const char *fn
, struct expression
*expr
, void *_param
)
284 int param
= PTR_INT(_param
);
285 struct expression
*dest
;
287 dest
= get_argument_from_call_expr(expr
->args
, param
);
288 dest
= strip_expr(dest
);
291 /* the first thing I tested this on pass &foo to a function */
292 set_state_expr(my_id
, dest
, &user_data
);
293 if (dest
->type
== EXPR_PREOP
&& dest
->op
== '&') {
294 /* but normally I'd think it would pass the actual variable */
296 set_state_expr(my_id
, dest
, &user_data
);
300 static void match_user_assign_function(const char *fn
, struct expression
*expr
, void *unused
)
302 set_state_expr(my_id
, expr
->left
, &user_data
);
305 static void match_assign_userdata(struct expression
*expr
)
307 if (is_user_data(expr
->right
))
308 set_state_expr(my_id
, expr
->left
, &user_data
);
311 static void match_caller_info(struct expression
*expr
)
313 struct expression
*tmp
;
317 FOR_EACH_PTR(expr
->args
, tmp
) {
318 if (is_user_data(tmp
))
319 sql_insert_caller_info(expr
, USER_DATA
, i
, "$$", "1");
321 } END_FOR_EACH_PTR(tmp
);
324 static void struct_member_callback(struct expression
*call
, int param
, char *printed_name
, struct smatch_state
*state
)
326 if (state
== &capped
)
328 sql_insert_caller_info(call
, USER_DATA
, param
, printed_name
, "1");
331 static void print_returned_user_data(int return_id
, char *return_ranges
, struct expression
*expr
, struct state_list
*slist
)
333 if (is_user_data(expr
)) {
334 sql_insert_return_states(return_id
, return_ranges
, USER_DATA
,
339 void check_user_data(int id
)
341 if (option_project
!= PROJ_KERNEL
)
344 add_definition_db_callback(set_param_user_data
, USER_DATA
);
345 add_hook(&match_syscall_definition
, FUNC_DEF_HOOK
);
346 add_hook(&match_condition
, CONDITION_HOOK
);
347 add_hook(&match_assign
, ASSIGNMENT_HOOK
);
348 add_hook(&match_assign_userdata
, ASSIGNMENT_HOOK
);
349 add_function_hook("copy_from_user", &match_user_copy
, INT_PTR(0));
350 add_function_hook("__copy_from_user", &match_user_copy
, INT_PTR(0));
351 add_function_hook("memcpy_fromiovec", &match_user_copy
, INT_PTR(0));
352 add_function_assign_hook("kmemdup_user", &match_user_assign_function
, NULL
);
354 add_hook(&match_caller_info
, FUNCTION_CALL_HOOK
);
355 add_member_info_callback(my_id
, struct_member_callback
);
356 add_returned_state_callback(print_returned_user_data
);