Messages in this thread | | | Date | Mon, 28 Sep 2015 18:40:30 +0300 | Subject | Re: [PATCH] arch/x86: fix out-of-bounds in get_wchan() | From | Andrey Ryabinin <> |
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2015-09-28 12:00 GMT+03:00 Dmitry Vyukov <dvyukov@google.com>: > stack = (unsigned long)task_stack_page(p); > - if (p->thread.sp < stack || p->thread.sp >= stack+THREAD_SIZE) > + /* The task can be already running at this point, so tread carefully. */ > + fp = READ_ONCE(p->thread.sp); > + if (fp < stack || fp >= stack+THREAD_SIZE)
Since we deference fp, it should be "|| fp + sizeof(u64) >= stack + THREAD_SIZE"
> return 0; > - fp = *(u64 *)(p->thread.sp); > + fp = READ_ONCE(*(u64 *)fp); > do { > if (fp < (unsigned long)stack || > - fp >= (unsigned long)stack+THREAD_SIZE) > + fp+8 >= (unsigned long)stack+THREAD_SIZE)
The same as above; 'fp+8 +sizeof(u64) >= ...'
> return 0; > - ip = *(u64 *)(fp+8); > + ip = READ_ONCE(*(u64 *)(fp+8)); >
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