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
= get_variable_from_expr(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 int is_user_data(struct expression
*expr
)
120 struct state_list
*slist
= NULL
;
121 struct sm_state
*tmp
;
132 if (is_user_macro(expr
))
134 if (is_user_function(expr
))
136 if (is_skb_data(expr
))
139 expr
= strip_expr(expr
); /* this has to come after is_user_macro() */
141 if (expr
->type
== EXPR_BINOP
) {
142 if (is_user_data(expr
->left
))
144 if (is_user_data(expr
->right
))
148 if (expr
->type
== EXPR_PREOP
&& (expr
->op
== '&' || expr
->op
== '*'))
149 expr
= strip_expr(expr
->unop
);
151 tmp
= get_sm_state_expr(my_id
, expr
);
153 return slist_has_state(tmp
->possible
, &user_data
);
155 name
= get_variable_from_expr_complex(expr
, &sym
);
159 slist
= get_all_states(my_id
);
160 FOR_EACH_PTR(slist
, tmp
) {
163 if (!strncmp(tmp
->name
, name
, strlen(tmp
->name
))) {
164 if (slist_has_state(tmp
->possible
, &user_data
))
168 } END_FOR_EACH_PTR(tmp
);
176 void set_param_user_data(const char *name
, struct symbol
*sym
, char *key
, char *value
)
180 if (strncmp(key
, "$$", 2))
182 snprintf(fullname
, 256, "%s%s", name
, key
+ 2);
183 set_state(my_id
, fullname
, sym
, &user_data
);
186 static void match_syscall_definition(struct symbol
*sym
)
191 macro
= get_macro_name(sym
->pos
);
194 if (strncmp("SYSCALL_DEFINE", macro
, strlen("SYSCALL_DEFINE")))
197 FOR_EACH_PTR(sym
->ctype
.base_type
->arguments
, arg
) {
198 set_state(my_id
, arg
->ident
->name
, arg
, &user_data
);
199 } END_FOR_EACH_PTR(arg
);
202 static void match_condition(struct expression
*expr
)
207 case SPECIAL_UNSIGNED_LT
:
208 case SPECIAL_UNSIGNED_LTE
:
209 if (is_user_data(expr
->left
))
210 set_true_false_states_expr(my_id
, expr
->left
, &capped
, NULL
);
211 if (is_user_data(expr
->right
))
212 set_true_false_states_expr(my_id
, expr
->right
, NULL
, &capped
);
216 case SPECIAL_UNSIGNED_GT
:
217 case SPECIAL_UNSIGNED_GTE
:
218 if (is_user_data(expr
->right
))
219 set_true_false_states_expr(my_id
, expr
->right
, &capped
, NULL
);
220 if (is_user_data(expr
->left
))
221 set_true_false_states_expr(my_id
, expr
->left
, NULL
, &capped
);
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
, &capped
, NULL
);
229 case SPECIAL_NOTEQUAL
:
230 if (is_user_data(expr
->left
))
231 set_true_false_states_expr(my_id
, expr
->left
, NULL
, &capped
);
232 if (is_user_data(expr
->right
))
233 set_true_false_states_expr(my_id
, expr
->right
, NULL
, &capped
);
240 static void match_normal_assign(struct expression
*expr
)
242 if (is_user_data(expr
->left
))
243 set_state_expr(my_id
, expr
->left
, &capped
);
246 static void match_assign(struct expression
*expr
)
250 name
= get_macro_name(expr
->pos
);
251 if (!name
|| strcmp(name
, "get_user") != 0) {
252 match_normal_assign(expr
);
255 name
= get_variable_from_expr(expr
->right
, NULL
);
256 if (!name
|| strcmp(name
, "__val_gu") != 0)
258 set_state_expr(my_id
, expr
->left
, &user_data
);
263 static void match_user_copy(const char *fn
, struct expression
*expr
, void *_param
)
265 int param
= PTR_INT(_param
);
266 struct expression
*dest
;
268 dest
= get_argument_from_call_expr(expr
->args
, param
);
269 dest
= strip_expr(dest
);
272 /* the first thing I tested this on pass &foo to a function */
273 set_state_expr(my_id
, dest
, &user_data
);
274 if (dest
->type
== EXPR_PREOP
&& dest
->op
== '&') {
275 /* but normally I'd think it would pass the actual variable */
277 set_state_expr(my_id
, dest
, &user_data
);
281 static void match_user_assign_function(const char *fn
, struct expression
*expr
, void *unused
)
283 set_state_expr(my_id
, expr
->left
, &user_data
);
286 static void match_assign_userdata(struct expression
*expr
)
288 if (is_user_data(expr
->right
))
289 set_state_expr(my_id
, expr
->left
, &user_data
);
292 static void match_caller_info(struct expression
*expr
)
294 struct expression
*tmp
;
298 func
= get_fnptr_name(expr
->fn
);
303 FOR_EACH_PTR(expr
->args
, tmp
) {
304 if (is_user_data(tmp
))
305 sm_msg("info: passes user_data '%s' %d '$$' %s", func
, i
,
306 is_static(expr
->fn
) ? "static" : "global");
308 } END_FOR_EACH_PTR(tmp
);
311 static void struct_member_callback(char *fn
, char *global_static
, int param
, char *printed_name
, struct smatch_state
*state
)
313 if (state
== &capped
)
315 sm_msg("info: passes user_data '%s' %d '%s' %s", fn
, param
, printed_name
, global_static
);
318 static void match_return(struct expression
*expr
)
320 if (is_user_data(expr
)) {
321 struct range_list_sval
*rl
;
323 get_implied_range_list_sval(expr
, &rl
);
324 sm_msg("info: returns_user_data %d '%s' %s",
325 get_return_id(), show_ranges_sval(rl
), global_static());
329 void check_user_data(int id
)
331 if (option_project
!= PROJ_KERNEL
)
334 add_definition_db_callback(set_param_user_data
, USER_DATA
);
335 add_hook(&match_syscall_definition
, FUNC_DEF_HOOK
);
336 add_hook(&match_condition
, CONDITION_HOOK
);
337 add_hook(&match_assign
, ASSIGNMENT_HOOK
);
338 add_hook(&match_assign_userdata
, ASSIGNMENT_HOOK
);
339 add_function_hook("copy_from_user", &match_user_copy
, INT_PTR(0));
340 add_function_hook("__copy_from_user", &match_user_copy
, INT_PTR(0));
341 add_function_hook("memcpy_fromiovec", &match_user_copy
, INT_PTR(0));
342 add_function_assign_hook("kmemdup_user", &match_user_assign_function
, NULL
);
344 add_hook(&match_caller_info
, FUNCTION_CALL_HOOK
);
345 add_member_info_callback(my_id
, struct_member_callback
);
346 add_hook(&match_return
, RETURN_HOOK
);