2 * smatch/smatch_buf_size.c
4 * Copyright (C) 2010 Dan Carpenter.
6 * Licensed under the Open Software License version 1.1
14 #include "smatch_slist.h"
15 #include "smatch_extra.h"
18 * This check has two smatch IDs.
19 * my_size_id - used to store the size of arrays.
20 * my_strlen_id - track the strlen() of buffers.
23 static int my_size_id
;
24 static int my_strlen_id
;
30 static struct limiter b0_l2
= {0, 2};
32 static _Bool params_set
[32];
34 static void set_undefined(struct sm_state
*sm
)
36 if (sm
->state
!= &undefined
)
37 set_state(sm
->owner
, sm
->name
, sm
->sym
, &undefined
);
40 static struct smatch_state
*merge_func(struct smatch_state
*s1
, struct smatch_state
*s2
)
42 if (PTR_INT(s1
->data
) == PTR_INT(s2
->data
))
47 void set_param_buf_size(const char *name
, struct symbol
*sym
, char *key
, char *value
)
52 if (strncmp(key
, "$$", 2))
55 snprintf(fullname
, 256, "%s%s", name
, key
+ 2);
58 size
= strtoul(value
, NULL
, 10);
62 set_state(my_size_id
, fullname
, sym
, alloc_state_num(size
));
65 static int bytes_per_element(struct expression
*expr
)
70 if (expr
->type
== EXPR_STRING
)
72 type
= get_type(expr
);
76 if (type
->type
!= SYM_PTR
&& type
->type
!= SYM_ARRAY
)
79 type
= get_base_type(type
);
80 bpe
= bits_to_bytes(type
->bit_size
);
82 if (bpe
== -1) /* void pointer */
88 static int bytes_to_elements(struct expression
*expr
, int bytes
)
92 bpe
= bytes_per_element(expr
);
98 static int elements_to_bytes(struct expression
*expr
, int elements
)
102 bpe
= bytes_per_element(expr
);
103 return elements
* bpe
;
106 static int get_initializer_size(struct expression
*expr
)
108 switch (expr
->type
) {
110 return expr
->string
->length
;
111 case EXPR_INITIALIZER
: {
112 struct expression
*tmp
;
116 FOR_EACH_PTR(expr
->expr_list
, tmp
) {
117 if (tmp
->type
== EXPR_INDEX
&& tmp
->idx_to
> max
)
120 } END_FOR_EACH_PTR(tmp
);
126 return get_array_size(expr
);
132 static int db_size_callback(void *unused
, int argc
, char **argv
, char **azColName
)
135 db_size
= atoi(argv
[0]);
141 static int size_from_db(struct expression
*expr
)
143 int this_file_only
= 0;
149 name
= get_member_name(expr
);
150 if (!name
&& is_static(expr
)) {
151 name
= expr_to_var(expr
);
158 run_sql(db_size_callback
, "select size from type_size where type = '%s' and file = '%s'",
159 name
, get_filename());
167 run_sql(db_size_callback
, "select size from type_size where type = '%s'",
176 static void db_returns_buf_size(struct expression
*expr
, int param
, char *unused
, char *math
)
178 struct expression
*call
;
181 if (expr
->type
!= EXPR_ASSIGNMENT
)
183 call
= strip_expr(expr
->right
);
185 if (!parse_call_math(call
, math
, &sval
))
187 set_state_expr(my_size_id
, expr
->left
, alloc_state_num(sval
.value
));
190 static int get_real_array_size(struct expression
*expr
)
195 if (expr
->type
== EXPR_BINOP
) /* array elements foo[5] */
198 type
= get_type(expr
);
199 if (!type
|| type
->type
!= SYM_ARRAY
)
202 if (!get_implied_value(type
->array_size
, &sval
))
205 /* People put one element arrays on the end of structs */
212 static int get_size_from_initializer(struct expression
*expr
)
214 if (expr
->type
!= EXPR_SYMBOL
|| !expr
->symbol
->initializer
)
216 if (expr
->symbol
->initializer
== expr
) /* int a = a; */
218 return get_initializer_size(expr
->symbol
->initializer
);
221 static int get_stored_size_bytes(struct expression
*expr
)
223 struct smatch_state
*state
;
225 state
= get_state_expr(my_size_id
, expr
);
228 return PTR_INT(state
->data
);
231 static int get_stored_size_bytes_min(struct expression
*expr
)
233 struct sm_state
*sm
, *tmp
;
236 sm
= get_sm_state_expr(my_size_id
, expr
);
239 FOR_EACH_PTR(sm
->possible
, tmp
) {
240 if (PTR_INT(tmp
->state
->data
) <= 0)
242 if (PTR_INT(tmp
->state
->data
) < min
)
243 min
= PTR_INT(tmp
->state
->data
);
244 } END_FOR_EACH_PTR(tmp
);
249 static int get_bytes_from_address(struct expression
*expr
)
256 if (expr
->type
!= EXPR_PREOP
|| expr
->op
!= '&')
258 type
= get_type(expr
);
262 if (type
->type
== SYM_PTR
)
263 type
= get_base_type(type
);
265 ret
= bits_to_bytes(type
->bit_size
);
269 return 0; /* ignore char pointers */
274 static int get_size_from_strlen(struct expression
*expr
)
276 struct smatch_state
*state
;
279 state
= get_state_expr(my_strlen_id
, expr
);
280 if (!state
|| !state
->data
)
282 if (!get_implied_max((struct expression
*)state
->data
, &len
))
284 if (sval_is_max(len
))
286 return len
.value
+ 1; /* add one because strlen doesn't include the NULL */
289 static struct expression
*remove_addr_fluff(struct expression
*expr
)
291 struct expression
*tmp
;
294 expr
= strip_expr(expr
);
296 /* remove '&' and '*' operations that cancel */
297 while (expr
->type
== EXPR_PREOP
&& expr
->op
== '&') {
298 tmp
= strip_expr(expr
->unop
);
299 if (tmp
->type
!= EXPR_PREOP
)
303 expr
= strip_expr(tmp
->unop
);
306 /* "foo + 0" is just "foo" */
307 if (expr
->type
== EXPR_BINOP
&& expr
->op
== '+' &&
308 get_value(expr
->right
, &sval
) && sval
.value
== 0)
314 int get_array_size_bytes(struct expression
*expr
)
318 expr
= remove_addr_fluff(expr
);
322 /* strcpy(foo, "BAR"); */
323 if (expr
->type
== EXPR_STRING
)
324 return expr
->string
->length
;
327 size
= get_real_array_size(expr
);
329 return elements_to_bytes(expr
, size
);
331 /* buf = malloc(1024); */
332 size
= get_stored_size_bytes(expr
);
336 /* char *foo = "BAR" */
337 size
= get_size_from_initializer(expr
);
339 return elements_to_bytes(expr
, size
);
341 size
= get_bytes_from_address(expr
);
345 /* if (strlen(foo) > 4) */
346 size
= get_size_from_strlen(expr
);
350 return size_from_db(expr
);
353 int get_array_size_bytes_min(struct expression
*expr
)
358 size
= get_array_size_bytes(expr
);
360 tmp
= get_stored_size_bytes_min(expr
);
361 if (size
<= 0 || (tmp
>= 1 && tmp
< size
))
366 int get_array_size(struct expression
*expr
)
370 bytes
= get_array_size_bytes(expr
);
371 return bytes_to_elements(expr
, bytes
);
374 static void match_strlen_condition(struct expression
*expr
)
376 struct expression
*left
;
377 struct expression
*right
;
378 struct expression
*str
= NULL
;
380 int strlen_right
= 0;
382 struct smatch_state
*true_state
= NULL
;
383 struct smatch_state
*false_state
= NULL
;
385 if (expr
->type
!= EXPR_COMPARE
)
387 left
= strip_expr(expr
->left
);
388 right
= strip_expr(expr
->right
);
390 if (left
->type
== EXPR_CALL
&& sym_name_is("strlen", left
->fn
)) {
391 str
= get_argument_from_call_expr(left
->args
, 0);
394 if (right
->type
== EXPR_CALL
&& sym_name_is("strlen", right
->fn
)) {
395 str
= get_argument_from_call_expr(right
->args
, 0);
399 if (!strlen_left
&& !strlen_right
)
401 if (strlen_left
&& strlen_right
)
405 if (!get_value(right
, &sval
))
409 if (!get_value(left
, &sval
))
413 if (expr
->op
== SPECIAL_EQUAL
) {
414 set_true_false_states_expr(my_size_id
, str
, alloc_state_num(sval
.value
+ 1), NULL
);
417 if (expr
->op
== SPECIAL_NOTEQUAL
) {
418 set_true_false_states_expr(my_size_id
, str
, NULL
, alloc_state_num(sval
.value
+ 1));
424 case SPECIAL_UNSIGNED_LT
:
426 true_state
= alloc_state_num(sval
.value
);
428 false_state
= alloc_state_num(sval
.value
+ 1);
431 case SPECIAL_UNSIGNED_LTE
:
433 true_state
= alloc_state_num(sval
.value
+ 1);
435 false_state
= alloc_state_num(sval
.value
);
438 case SPECIAL_UNSIGNED_GTE
:
440 false_state
= alloc_state_num(sval
.value
);
442 true_state
= alloc_state_num(sval
.value
+ 1);
445 case SPECIAL_UNSIGNED_GT
:
447 false_state
= alloc_state_num(sval
.value
+ 1);
449 true_state
= alloc_state_num(sval
.value
);
452 set_true_false_states_expr(my_size_id
, str
, true_state
, false_state
);
455 static struct expression
*strip_ampersands(struct expression
*expr
)
459 if (expr
->type
!= EXPR_PREOP
)
463 type
= get_type(expr
->unop
);
464 if (!type
|| type
->type
!= SYM_ARRAY
)
469 static void match_array_assignment(struct expression
*expr
)
471 struct expression
*left
;
472 struct expression
*right
;
477 left
= strip_expr(expr
->left
);
478 right
= strip_expr(expr
->right
);
479 right
= strip_ampersands(right
);
480 array_size
= get_array_size_bytes(right
);
482 set_state_expr(my_size_id
, left
, alloc_state_num(array_size
));
485 static void info_record_alloction(struct expression
*buffer
, struct expression
*size
)
493 name
= get_member_name(buffer
);
494 if (!name
&& is_static(buffer
))
495 name
= expr_to_var(buffer
);
498 if (get_implied_value(size
, &sval
))
499 sm_msg("info: '%s' allocated_buf_size %s", name
, sval_to_str(sval
));
501 sm_msg("info: '%s' allocated_buf_size -1", name
);
505 static void match_alloc(const char *fn
, struct expression
*expr
, void *_size_arg
)
507 int size_arg
= PTR_INT(_size_arg
);
508 struct expression
*right
;
509 struct expression
*arg
;
512 right
= strip_expr(expr
->right
);
513 arg
= get_argument_from_call_expr(right
->args
, size_arg
);
515 info_record_alloction(expr
->left
, arg
);
517 if (!get_implied_value(arg
, &bytes
))
519 set_state_expr(my_size_id
, expr
->left
, alloc_state_num(bytes
.value
));
522 static void match_calloc(const char *fn
, struct expression
*expr
, void *unused
)
524 struct expression
*right
;
525 struct expression
*arg
;
529 right
= strip_expr(expr
->right
);
530 arg
= get_argument_from_call_expr(right
->args
, 0);
531 if (!get_implied_value(arg
, &elements
))
533 arg
= get_argument_from_call_expr(right
->args
, 1);
534 if (!get_implied_value(arg
, &size
))
536 set_state_expr(my_size_id
, expr
->left
, alloc_state_num(elements
.value
* size
.value
));
539 static void match_strlen(const char *fn
, struct expression
*expr
, void *unused
)
541 struct expression
*right
;
542 struct expression
*str
;
543 struct expression
*len_expr
;
545 struct smatch_state
*state
;
547 right
= strip_expr(expr
->right
);
548 str
= get_argument_from_call_expr(right
->args
, 0);
549 len_expr
= strip_expr(expr
->left
);
551 len_name
= expr_to_var(len_expr
);
555 state
= __alloc_smatch_state(0);
556 state
->name
= len_name
;
557 state
->data
= len_expr
;
558 set_state_expr(my_strlen_id
, str
, state
);
561 static void match_limited(const char *fn
, struct expression
*expr
, void *_limiter
)
563 struct limiter
*limiter
= (struct limiter
*)_limiter
;
564 struct expression
*dest
;
565 struct expression
*size_expr
;
568 dest
= get_argument_from_call_expr(expr
->args
, limiter
->buf_arg
);
569 size_expr
= get_argument_from_call_expr(expr
->args
, limiter
->limit_arg
);
570 if (!get_implied_max(size_expr
, &size
))
572 set_state_expr(my_size_id
, dest
, alloc_state_num(size
.value
));
575 static void match_strcpy(const char *fn
, struct expression
*expr
, void *unused
)
577 struct expression fake_assign
;
579 fake_assign
.op
= '=';
580 fake_assign
.left
= get_argument_from_call_expr(expr
->args
, 0);
581 fake_assign
.right
= get_argument_from_call_expr(expr
->args
, 1);
582 match_array_assignment(&fake_assign
);
585 static void match_strndup(const char *fn
, struct expression
*expr
, void *unused
)
587 struct expression
*fn_expr
;
588 struct expression
*size_expr
;
591 fn_expr
= strip_expr(expr
->right
);
592 size_expr
= get_argument_from_call_expr(fn_expr
->args
, 1);
593 if (!get_implied_max(size_expr
, &size
))
596 /* It's easy to forget space for the NUL char */
598 set_state_expr(my_size_id
, expr
->left
, alloc_state_num(size
.value
));
601 static void match_call(struct expression
*expr
)
604 struct expression
*arg
;
608 name
= get_fnptr_name(expr
->fn
);
613 FOR_EACH_PTR(expr
->args
, arg
) {
614 bytes
= get_array_size_bytes(arg
);
616 sm_msg("info: passes_buffer '%s' %d '$$' %d %s",
618 is_static(expr
->fn
) ? "static" : "global");
620 } END_FOR_EACH_PTR(arg
);
625 static void struct_member_callback(char *fn
, char *global_static
, int param
, char *printed_name
, struct smatch_state
*state
)
627 if (state
== &merged
)
629 sm_msg("info: passes_buffer '%s' %d '%s' %s %s", fn
, param
, printed_name
, state
->name
, global_static
);
632 static void match_func_end(struct symbol
*sym
)
634 memset(params_set
, 0, sizeof(params_set
));
637 void register_buf_size(int id
)
641 add_definition_db_callback(set_param_buf_size
, BUF_SIZE
);
642 add_db_return_states_callback(BUF_SIZE
, &db_returns_buf_size
);
644 add_function_assign_hook("malloc", &match_alloc
, INT_PTR(0));
645 add_function_assign_hook("calloc", &match_calloc
, NULL
);
646 add_function_assign_hook("memdup", &match_alloc
, INT_PTR(1));
647 if (option_project
== PROJ_KERNEL
) {
648 add_function_assign_hook("kmalloc", &match_alloc
, INT_PTR(0));
649 add_function_assign_hook("kzalloc", &match_alloc
, INT_PTR(0));
650 add_function_assign_hook("vmalloc", &match_alloc
, INT_PTR(0));
651 add_function_assign_hook("__vmalloc", &match_alloc
, INT_PTR(0));
652 add_function_assign_hook("kcalloc", &match_calloc
, NULL
);
653 add_function_assign_hook("kmalloc_array", &match_calloc
, NULL
);
654 add_function_assign_hook("drm_malloc_ab", &match_calloc
, NULL
);
655 add_function_assign_hook("drm_calloc_large", &match_calloc
, NULL
);
656 add_function_assign_hook("sock_kmalloc", &match_alloc
, INT_PTR(1));
657 add_function_assign_hook("kmemdup", &match_alloc
, INT_PTR(1));
658 add_function_assign_hook("kmemdup_user", &match_alloc
, INT_PTR(1));
660 add_hook(&match_array_assignment
, ASSIGNMENT_HOOK
);
661 add_hook(&match_strlen_condition
, CONDITION_HOOK
);
662 add_function_assign_hook("strlen", &match_strlen
, NULL
);
664 add_function_assign_hook("strndup", match_strndup
, NULL
);
665 if (option_project
== PROJ_KERNEL
)
666 add_function_assign_hook("kstrndup", match_strndup
, NULL
);
668 add_hook(&match_func_end
, END_FUNC_HOOK
);
669 add_modification_hook(my_size_id
, &set_undefined
);
671 add_merge_hook(my_size_id
, &merge_func
);
674 void register_strlen(int id
)
677 add_modification_hook(my_strlen_id
, &set_undefined
);
678 add_merge_hook(my_strlen_id
, &merge_func
);
681 void register_buf_size_late(int id
)
683 add_function_hook("strlcpy", &match_limited
, &b0_l2
);
684 add_function_hook("strlcat", &match_limited
, &b0_l2
);
685 add_function_hook("memscan", &match_limited
, &b0_l2
);
687 add_function_hook("strcpy", &match_strcpy
, NULL
);
690 add_hook(&match_call
, FUNCTION_CALL_HOOK
);
691 add_member_info_callback(my_size_id
, struct_member_callback
);