static int
lookup_bad_addr(const int type, const unsigned long addr, const size_t size)
{
/* Is this a valid memory access?
*
* Note we're using access_ok() here. This is only supposed to be
* called when we're in task context. Occasionally lookup_bad_addr()
* gets called when not in task context. If in_task() exists, only
* call access_ok() when we're in task context (otherwise we'll get
* a kernel warning). If we aren't in task context, we'll just do a
* range check.
*/
#if !defined(in_task)
if (size == 0 || ULONG_MAX - addr < size - 1
|| !access_ok(type, (void *)addr, size))
return 1;
#else
if (size == 0 || ULONG_MAX - addr < size - 1
|| (in_task() && !access_ok(type, (void *)addr, size))
|| (!in_task()
#if defined(user_addr_max)
&& ((user_addr_max() - size) < addr)
#endif
))
return 1;
#endif
#if ! STP_PRIVILEGE_CONTAINS (STP_PRIVILEGE, STP_PR_STAPDEV) && \
! STP_PRIVILEGE_CONTAINS (STP_PRIVILEGE, STP_PR_STAPSYS)
/* Unprivileged users must not access memory while the context
does not refer to their own process. */
if (! is_myproc ())
return 1;
/* Unprivileged users must not access kernel space memory. */
if (addr + size > TASK_SIZE)
return 1;
#endif
return 0;
}
/*
* Entry point from instrumented code.
* This is called once per basic-block/edge.
*/
void notrace __sanitizer_cov_trace_pc(void)
{
struct task_struct *t;
enum kcov_mode mode;
t = current;
/*
* We are interested in code coverage as a function of a syscall inputs,
* so we ignore code executed in interrupts.
*/
if (!t || !in_task())
return;
mode = READ_ONCE(t->kcov_mode);
if (mode == KCOV_MODE_TRACE) {
unsigned long *area;
unsigned long pos;
unsigned long ip = _RET_IP_;
#ifdef CONFIG_RANDOMIZE_BASE
ip -= kaslr_offset();
#endif
/*
* There is some code that runs in interrupts but for which
* in_interrupt() returns false (e.g. preempt_schedule_irq()).
* READ_ONCE()/barrier() effectively provides load-acquire wrt
* interrupts, there are paired barrier()/WRITE_ONCE() in
* kcov_ioctl_locked().
*/
barrier();
area = t->kcov_area;
/* The first word is number of subsequent PCs. */
pos = READ_ONCE(area[0]) + 1;
if (likely(pos < t->kcov_size)) {
area[pos] = ip;
WRITE_ONCE(area[0], pos);
}
}
}
