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bebarinoKAGA-KOKO
bebarino
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KAGA-KOKO
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debugobjects: Allow debug_obj_descr to be const
The debugobject core could be slightly harder to corrupt if the debug_obj_descr would be a pointer to const memory. Depending on the architecture, const data structures are placed into read-only memory and thus are harder to corrupt or hijack. This descriptor is used to fix up stuff like timers and workqueues when core kernel data structures are busted, so moving the descriptors to read-only memory will make debugobjects more resilient to something going wrong and then corrupting the function pointers inside struct debug_obj_descr. Signed-off-by: Stephen Boyd <swboyd@chromium.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20200815004027.2046113-2-swboyd@chromium.org
1 parent 805c6d3 commit aedcade

2 files changed

Lines changed: 31 additions & 31 deletions

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‎include/linux/debugobjects.h‎

Lines changed: 16 additions & 16 deletions
Original file line numberDiff line numberDiff line change
@@ -30,7 +30,7 @@ struct debug_obj {
3030
enum debug_obj_state state;
3131
unsigned int astate;
3232
void *object;
33-
struct debug_obj_descr *descr;
33+
const struct debug_obj_descr *descr;
3434
};
3535

3636
/**
@@ -64,41 +64,41 @@ struct debug_obj_descr {
6464
};
6565

6666
#ifdef CONFIG_DEBUG_OBJECTS
67-
extern void debug_object_init (void *addr, struct debug_obj_descr *descr);
67+
extern void debug_object_init (void *addr, const struct debug_obj_descr *descr);
6868
extern void
69-
debug_object_init_on_stack(void *addr, struct debug_obj_descr *descr);
70-
extern int debug_object_activate (void *addr, struct debug_obj_descr *descr);
71-
extern void debug_object_deactivate(void *addr, struct debug_obj_descr *descr);
72-
extern void debug_object_destroy (void *addr, struct debug_obj_descr *descr);
73-
extern void debug_object_free (void *addr, struct debug_obj_descr *descr);
74-
extern void debug_object_assert_init(void *addr, struct debug_obj_descr *descr);
69+
debug_object_init_on_stack(void *addr, const struct debug_obj_descr *descr);
70+
extern int debug_object_activate (void *addr, const struct debug_obj_descr *descr);
71+
extern void debug_object_deactivate(void *addr, const struct debug_obj_descr *descr);
72+
extern void debug_object_destroy (void *addr, const struct debug_obj_descr *descr);
73+
extern void debug_object_free (void *addr, const struct debug_obj_descr *descr);
74+
extern void debug_object_assert_init(void *addr, const struct debug_obj_descr *descr);
7575

7676
/*
7777
* Active state:
7878
* - Set at 0 upon initialization.
7979
* - Must return to 0 before deactivation.
8080
*/
8181
extern void
82-
debug_object_active_state(void *addr, struct debug_obj_descr *descr,
82+
debug_object_active_state(void *addr, const struct debug_obj_descr *descr,
8383
unsigned int expect, unsigned int next);
8484

8585
extern void debug_objects_early_init(void);
8686
extern void debug_objects_mem_init(void);
8787
#else
8888
static inline void
89-
debug_object_init (void *addr, struct debug_obj_descr *descr) { }
89+
debug_object_init (void *addr, const struct debug_obj_descr *descr) { }
9090
static inline void
91-
debug_object_init_on_stack(void *addr, struct debug_obj_descr *descr) { }
91+
debug_object_init_on_stack(void *addr, const struct debug_obj_descr *descr) { }
9292
static inline int
93-
debug_object_activate (void *addr, struct debug_obj_descr *descr) { return 0; }
93+
debug_object_activate (void *addr, const struct debug_obj_descr *descr) { return 0; }
9494
static inline void
95-
debug_object_deactivate(void *addr, struct debug_obj_descr *descr) { }
95+
debug_object_deactivate(void *addr, const struct debug_obj_descr *descr) { }
9696
static inline void
97-
debug_object_destroy (void *addr, struct debug_obj_descr *descr) { }
97+
debug_object_destroy (void *addr, const struct debug_obj_descr *descr) { }
9898
static inline void
99-
debug_object_free (void *addr, struct debug_obj_descr *descr) { }
99+
debug_object_free (void *addr, const struct debug_obj_descr *descr) { }
100100
static inline void
101-
debug_object_assert_init(void *addr, struct debug_obj_descr *descr) { }
101+
debug_object_assert_init(void *addr, const struct debug_obj_descr *descr) { }
102102

103103
static inline void debug_objects_early_init(void) { }
104104
static inline void debug_objects_mem_init(void) { }

‎lib/debugobjects.c‎

Lines changed: 15 additions & 15 deletions
Original file line numberDiff line numberDiff line change
@@ -90,7 +90,7 @@ static int debug_objects_pool_size __read_mostly
9090
= ODEBUG_POOL_SIZE;
9191
static int debug_objects_pool_min_level __read_mostly
9292
= ODEBUG_POOL_MIN_LEVEL;
93-
static struct debug_obj_descr *descr_test __read_mostly;
93+
static const struct debug_obj_descr *descr_test __read_mostly;
9494
static struct kmem_cache *obj_cache __read_mostly;
9595

9696
/*
@@ -223,7 +223,7 @@ static struct debug_obj *__alloc_object(struct hlist_head *list)
223223
* Must be called with interrupts disabled.
224224
*/
225225
static struct debug_obj *
226-
alloc_object(void *addr, struct debug_bucket *b, struct debug_obj_descr *descr)
226+
alloc_object(void *addr, struct debug_bucket *b, const struct debug_obj_descr *descr)
227227
{
228228
struct debug_percpu_free *percpu_pool = this_cpu_ptr(&percpu_obj_pool);
229229
struct debug_obj *obj;
@@ -475,7 +475,7 @@ static struct debug_bucket *get_bucket(unsigned long addr)
475475

476476
static void debug_print_object(struct debug_obj *obj, char *msg)
477477
{
478-
struct debug_obj_descr *descr = obj->descr;
478+
const struct debug_obj_descr *descr = obj->descr;
479479
static int limit;
480480

481481
if (limit < 5 && descr != descr_test) {
@@ -529,7 +529,7 @@ static void debug_object_is_on_stack(void *addr, int onstack)
529529
}
530530

531531
static void
532-
__debug_object_init(void *addr, struct debug_obj_descr *descr, int onstack)
532+
__debug_object_init(void *addr, const struct debug_obj_descr *descr, int onstack)
533533
{
534534
enum debug_obj_state state;
535535
bool check_stack = false;
@@ -587,7 +587,7 @@ __debug_object_init(void *addr, struct debug_obj_descr *descr, int onstack)
587587
* @addr: address of the object
588588
* @descr: pointer to an object specific debug description structure
589589
*/
590-
void debug_object_init(void *addr, struct debug_obj_descr *descr)
590+
void debug_object_init(void *addr, const struct debug_obj_descr *descr)
591591
{
592592
if (!debug_objects_enabled)
593593
return;
@@ -602,7 +602,7 @@ EXPORT_SYMBOL_GPL(debug_object_init);
602602
* @addr: address of the object
603603
* @descr: pointer to an object specific debug description structure
604604
*/
605-
void debug_object_init_on_stack(void *addr, struct debug_obj_descr *descr)
605+
void debug_object_init_on_stack(void *addr, const struct debug_obj_descr *descr)
606606
{
607607
if (!debug_objects_enabled)
608608
return;
@@ -617,7 +617,7 @@ EXPORT_SYMBOL_GPL(debug_object_init_on_stack);
617617
* @descr: pointer to an object specific debug description structure
618618
* Returns 0 for success, -EINVAL for check failed.
619619
*/
620-
int debug_object_activate(void *addr, struct debug_obj_descr *descr)
620+
int debug_object_activate(void *addr, const struct debug_obj_descr *descr)
621621
{
622622
enum debug_obj_state state;
623623
struct debug_bucket *db;
@@ -695,7 +695,7 @@ EXPORT_SYMBOL_GPL(debug_object_activate);
695695
* @addr: address of the object
696696
* @descr: pointer to an object specific debug description structure
697697
*/
698-
void debug_object_deactivate(void *addr, struct debug_obj_descr *descr)
698+
void debug_object_deactivate(void *addr, const struct debug_obj_descr *descr)
699699
{
700700
struct debug_bucket *db;
701701
struct debug_obj *obj;
@@ -747,7 +747,7 @@ EXPORT_SYMBOL_GPL(debug_object_deactivate);
747747
* @addr: address of the object
748748
* @descr: pointer to an object specific debug description structure
749749
*/
750-
void debug_object_destroy(void *addr, struct debug_obj_descr *descr)
750+
void debug_object_destroy(void *addr, const struct debug_obj_descr *descr)
751751
{
752752
enum debug_obj_state state;
753753
struct debug_bucket *db;
@@ -797,7 +797,7 @@ EXPORT_SYMBOL_GPL(debug_object_destroy);
797797
* @addr: address of the object
798798
* @descr: pointer to an object specific debug description structure
799799
*/
800-
void debug_object_free(void *addr, struct debug_obj_descr *descr)
800+
void debug_object_free(void *addr, const struct debug_obj_descr *descr)
801801
{
802802
enum debug_obj_state state;
803803
struct debug_bucket *db;
@@ -838,7 +838,7 @@ EXPORT_SYMBOL_GPL(debug_object_free);
838838
* @addr: address of the object
839839
* @descr: pointer to an object specific debug description structure
840840
*/
841-
void debug_object_assert_init(void *addr, struct debug_obj_descr *descr)
841+
void debug_object_assert_init(void *addr, const struct debug_obj_descr *descr)
842842
{
843843
struct debug_bucket *db;
844844
struct debug_obj *obj;
@@ -886,7 +886,7 @@ EXPORT_SYMBOL_GPL(debug_object_assert_init);
886886
* @next: state to move to if expected state is found
887887
*/
888888
void
889-
debug_object_active_state(void *addr, struct debug_obj_descr *descr,
889+
debug_object_active_state(void *addr, const struct debug_obj_descr *descr,
890890
unsigned int expect, unsigned int next)
891891
{
892892
struct debug_bucket *db;
@@ -934,7 +934,7 @@ EXPORT_SYMBOL_GPL(debug_object_active_state);
934934
static void __debug_check_no_obj_freed(const void *address, unsigned long size)
935935
{
936936
unsigned long flags, oaddr, saddr, eaddr, paddr, chunks;
937-
struct debug_obj_descr *descr;
937+
const struct debug_obj_descr *descr;
938938
enum debug_obj_state state;
939939
struct debug_bucket *db;
940940
struct hlist_node *tmp;
@@ -1052,7 +1052,7 @@ struct self_test {
10521052
unsigned long dummy2[3];
10531053
};
10541054

1055-
static __initdata struct debug_obj_descr descr_type_test;
1055+
static __initconst const struct debug_obj_descr descr_type_test;
10561056

10571057
static bool __init is_static_object(void *addr)
10581058
{
@@ -1177,7 +1177,7 @@ check_results(void *addr, enum debug_obj_state state, int fixups, int warnings)
11771177
return res;
11781178
}
11791179

1180-
static __initdata struct debug_obj_descr descr_type_test = {
1180+
static __initconst const struct debug_obj_descr descr_type_test = {
11811181
.name = "selftest",
11821182
.is_static_object = is_static_object,
11831183
.fixup_init = fixup_init,

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