diff options
Diffstat (limited to 'include/linux/stackleak.h')
-rw-r--r-- | include/linux/stackleak.h | 26 |
1 files changed, 26 insertions, 0 deletions
diff --git a/include/linux/stackleak.h b/include/linux/stackleak.h index 467661aeb413..c36e7a3b45e7 100644 --- a/include/linux/stackleak.h +++ b/include/linux/stackleak.h @@ -42,6 +42,32 @@ stackleak_task_high_bound(const struct task_struct *tsk) return (unsigned long)task_pt_regs(tsk); } +/* + * Find the address immediately above the poisoned region of the stack, where + * that region falls between 'low' (inclusive) and 'high' (exclusive). + */ +static __always_inline unsigned long +stackleak_find_top_of_poison(const unsigned long low, const unsigned long high) +{ + const unsigned int depth = STACKLEAK_SEARCH_DEPTH / sizeof(unsigned long); + unsigned int poison_count = 0; + unsigned long poison_high = high; + unsigned long sp = high; + + while (sp > low && poison_count < depth) { + sp -= sizeof(unsigned long); + + if (*(unsigned long *)sp == STACKLEAK_POISON) { + poison_count++; + } else { + poison_count = 0; + poison_high = sp; + } + } + + return poison_high; +} + static inline void stackleak_task_init(struct task_struct *t) { t->lowest_stack = stackleak_task_low_bound(t); |