diff options
| -rw-r--r-- | mm/kfence/core.c | 34 |
1 files changed, 34 insertions, 0 deletions
diff --git a/mm/kfence/core.c b/mm/kfence/core.c index 9b2b5f56f4ae..6e69986c3f0d 100644 --- a/mm/kfence/core.c +++ b/mm/kfence/core.c @@ -21,6 +21,8 @@ #include <linux/log2.h> #include <linux/memblock.h> #include <linux/moduleparam.h> +#include <linux/notifier.h> +#include <linux/panic_notifier.h> #include <linux/random.h> #include <linux/rcupdate.h> #include <linux/sched/clock.h> @@ -99,6 +101,10 @@ module_param_named(skip_covered_thresh, kfence_skip_covered_thresh, ulong, 0644) static bool kfence_deferrable __read_mostly = IS_ENABLED(CONFIG_KFENCE_DEFERRABLE); module_param_named(deferrable, kfence_deferrable, bool, 0444); +/* If true, check all canary bytes on panic. */ +static bool kfence_check_on_panic __read_mostly; +module_param_named(check_on_panic, kfence_check_on_panic, bool, 0444); + /* The pool of pages used for guard pages and objects. */ char *__kfence_pool __read_mostly; EXPORT_SYMBOL(__kfence_pool); /* Export for test modules. */ @@ -727,6 +733,31 @@ static int __init kfence_debugfs_init(void) late_initcall(kfence_debugfs_init); +/* === Panic Notifier ====================================================== */ + +static void kfence_check_all_canary(void) +{ + int i; + + for (i = 0; i < CONFIG_KFENCE_NUM_OBJECTS; i++) { + struct kfence_metadata *meta = &kfence_metadata[i]; + + if (meta->state == KFENCE_OBJECT_ALLOCATED) + for_each_canary(meta, check_canary_byte); + } +} + +static int kfence_check_canary_callback(struct notifier_block *nb, + unsigned long reason, void *arg) +{ + kfence_check_all_canary(); + return NOTIFY_OK; +} + +static struct notifier_block kfence_check_canary_notifier = { + .notifier_call = kfence_check_canary_callback, +}; + /* === Allocation Gate Timer ================================================ */ static struct delayed_work kfence_timer; @@ -804,6 +835,9 @@ static void kfence_init_enable(void) else INIT_DELAYED_WORK(&kfence_timer, toggle_allocation_gate); + if (kfence_check_on_panic) + atomic_notifier_chain_register(&panic_notifier_list, &kfence_check_canary_notifier); + WRITE_ONCE(kfence_enabled, true); queue_delayed_work(system_unbound_wq, &kfence_timer, 0); |