diff options
Diffstat (limited to 'kernel/stackleak.c')
| -rw-r--r-- | kernel/stackleak.c | 38 |
1 files changed, 38 insertions, 0 deletions
diff --git a/kernel/stackleak.c b/kernel/stackleak.c index f66239572c89..e42892926244 100644 --- a/kernel/stackleak.c +++ b/kernel/stackleak.c @@ -12,6 +12,41 @@ #include <linux/stackleak.h> +#ifdef CONFIG_STACKLEAK_RUNTIME_DISABLE +#include <linux/jump_label.h> +#include <linux/sysctl.h> + +static DEFINE_STATIC_KEY_FALSE(stack_erasing_bypass); + +int stack_erasing_sysctl(struct ctl_table *table, int write, + void __user *buffer, size_t *lenp, loff_t *ppos) +{ + int ret = 0; + int state = !static_branch_unlikely(&stack_erasing_bypass); + int prev_state = state; + + table->data = &state; + table->maxlen = sizeof(int); + ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos); + state = !!state; + if (ret || !write || state == prev_state) + return ret; + + if (state) + static_branch_disable(&stack_erasing_bypass); + else + static_branch_enable(&stack_erasing_bypass); + + pr_warn("stackleak: kernel stack erasing is %s\n", + state ? "enabled" : "disabled"); + return ret; +} + +#define skip_erasing() static_branch_unlikely(&stack_erasing_bypass) +#else +#define skip_erasing() false +#endif /* CONFIG_STACKLEAK_RUNTIME_DISABLE */ + asmlinkage void stackleak_erase(void) { /* It would be nice not to have 'kstack_ptr' and 'boundary' on stack */ @@ -20,6 +55,9 @@ asmlinkage void stackleak_erase(void) unsigned int poison_count = 0; const unsigned int depth = STACKLEAK_SEARCH_DEPTH / sizeof(unsigned long); + if (skip_erasing()) + return; + /* Check that 'lowest_stack' value is sane */ if (unlikely(kstack_ptr - boundary >= THREAD_SIZE)) kstack_ptr = boundary; |