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
))
161 if (is_user_data(expr
->right
))
165 if (expr
->type
== EXPR_PREOP
&& (expr
->op
== '&' || expr
->op
== '*'))
166 expr
= strip_expr(expr
->unop
);
168 tmp
= get_sm_state_expr(my_id
, expr
);
170 return slist_has_state(tmp
->possible
, &user_data
);
172 name
= expr_to_str_sym(expr
, &sym
);
176 slist
= get_all_states(my_id
);
177 FOR_EACH_PTR(slist
, tmp
) {
180 if (!strncmp(tmp
->name
, name
, strlen(tmp
->name
))) {
181 if (slist_has_state(tmp
->possible
, &user_data
))
185 } END_FOR_EACH_PTR(tmp
);
193 void set_param_user_data(const char *name
, struct symbol
*sym
, char *key
, char *value
)
197 if (strncmp(key
, "$$", 2))
199 snprintf(fullname
, 256, "%s%s", name
, key
+ 2);
200 set_state(my_id
, fullname
, sym
, &user_data
);
203 static void match_syscall_definition(struct symbol
*sym
)
208 macro
= get_macro_name(sym
->pos
);
211 if (strncmp("SYSCALL_DEFINE", macro
, strlen("SYSCALL_DEFINE")))
214 FOR_EACH_PTR(sym
->ctype
.base_type
->arguments
, arg
) {
215 set_state(my_id
, arg
->ident
->name
, arg
, &user_data
);
216 } END_FOR_EACH_PTR(arg
);
219 static void match_condition(struct expression
*expr
)
224 case SPECIAL_UNSIGNED_LT
:
225 case SPECIAL_UNSIGNED_LTE
:
226 if (is_user_data(expr
->left
))
227 set_true_false_states_expr(my_id
, expr
->left
, &capped
, NULL
);
228 if (is_user_data(expr
->right
))
229 set_true_false_states_expr(my_id
, expr
->right
, NULL
, &capped
);
233 case SPECIAL_UNSIGNED_GT
:
234 case SPECIAL_UNSIGNED_GTE
:
235 if (is_user_data(expr
->right
))
236 set_true_false_states_expr(my_id
, expr
->right
, &capped
, NULL
);
237 if (is_user_data(expr
->left
))
238 set_true_false_states_expr(my_id
, expr
->left
, NULL
, &capped
);
241 if (is_user_data(expr
->left
))
242 set_true_false_states_expr(my_id
, expr
->left
, &capped
, NULL
);
243 if (is_user_data(expr
->right
))
244 set_true_false_states_expr(my_id
, expr
->right
, &capped
, NULL
);
246 case SPECIAL_NOTEQUAL
:
247 if (is_user_data(expr
->left
))
248 set_true_false_states_expr(my_id
, expr
->left
, NULL
, &capped
);
249 if (is_user_data(expr
->right
))
250 set_true_false_states_expr(my_id
, expr
->right
, NULL
, &capped
);
257 static void match_normal_assign(struct expression
*expr
)
259 if (is_user_data(expr
->right
))
260 set_state_expr(my_id
, expr
->left
, &user_data
);
263 if (is_user_data(expr
->left
))
264 set_state_expr(my_id
, expr
->left
, &capped
);
267 static void match_assign(struct expression
*expr
)
271 name
= get_macro_name(expr
->pos
);
272 if (!name
|| strcmp(name
, "get_user") != 0) {
273 match_normal_assign(expr
);
276 name
= expr_to_var(expr
->right
);
277 if (!name
|| strcmp(name
, "__val_gu") != 0)
279 set_state_expr(my_id
, expr
->left
, &user_data
);
284 static void match_user_copy(const char *fn
, struct expression
*expr
, void *_param
)
286 int param
= PTR_INT(_param
);
287 struct expression
*dest
;
289 dest
= get_argument_from_call_expr(expr
->args
, param
);
290 dest
= strip_expr(dest
);
293 /* the first thing I tested this on pass &foo to a function */
294 set_state_expr(my_id
, dest
, &user_data
);
295 if (dest
->type
== EXPR_PREOP
&& dest
->op
== '&') {
296 /* but normally I'd think it would pass the actual variable */
298 set_state_expr(my_id
, dest
, &user_data
);
302 static void match_user_assign_function(const char *fn
, struct expression
*expr
, void *unused
)
304 set_state_expr(my_id
, expr
->left
, &user_data
);
307 static void match_assign_userdata(struct expression
*expr
)
309 if (is_user_data(expr
->right
))
310 set_state_expr(my_id
, expr
->left
, &user_data
);
313 static void match_caller_info(struct expression
*expr
)
315 struct expression
*tmp
;
319 FOR_EACH_PTR(expr
->args
, tmp
) {
320 if (is_user_data(tmp
))
321 sql_insert_caller_info(expr
, USER_DATA
, i
, "$$", "1");
323 } END_FOR_EACH_PTR(tmp
);
326 static void struct_member_callback(struct expression
*call
, int param
, char *printed_name
, struct smatch_state
*state
)
328 if (state
== &capped
)
330 sql_insert_caller_info(call
, USER_DATA
, param
, printed_name
, "1");
333 static void print_returned_user_data(int return_id
, char *return_ranges
, struct expression
*expr
, struct state_list
*slist
)
335 if (is_user_data(expr
)) {
336 sql_insert_return_states(return_id
, return_ranges
, USER_DATA
,
341 void check_user_data(int id
)
343 if (option_project
!= PROJ_KERNEL
)
346 add_definition_db_callback(set_param_user_data
, USER_DATA
);
347 add_hook(&match_syscall_definition
, FUNC_DEF_HOOK
);
348 add_hook(&match_condition
, CONDITION_HOOK
);
349 add_hook(&match_assign
, ASSIGNMENT_HOOK
);
350 add_hook(&match_assign_userdata
, ASSIGNMENT_HOOK
);
351 add_function_hook("copy_from_user", &match_user_copy
, INT_PTR(0));
352 add_function_hook("__copy_from_user", &match_user_copy
, INT_PTR(0));
353 add_function_hook("memcpy_fromiovec", &match_user_copy
, INT_PTR(0));
354 add_function_assign_hook("kmemdup_user", &match_user_assign_function
, NULL
);
356 add_hook(&match_caller_info
, FUNCTION_CALL_HOOK
);
357 add_member_info_callback(my_id
, struct_member_callback
);
358 add_returned_state_callback(print_returned_user_data
);