Commit d39a7435 authored Apr 27, 2014 by Richard Cochran Committed by David S. Miller Apr 28, 2014

ptp: validate the requested frequency adjustment.



PTP Hardware Clock drivers specify a maximum frequency adjustment that
their clocks can accommodate. Normally, user space programs will want to
respect the advertised limits. However, no kernel or driver code checks
that the dialed frequency offset is within the bounds, and out of range
values can lead to surprising results.

This patch fixes the issue by rejecting bad values.

Signed-off-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 5a2b646f

drivers/ptp/ptp_clock.c

+4 −1

Original line number	Diff line number	Diff line
		@@ -142,7 +142,10 @@ static int ptp_clock_adjtime(struct posix_clock pc, struct timex tx)
		delta = ktime_to_ns(kt);
		err = ops->adjtime(ops, delta);
		} else if (tx->modes & ADJ_FREQUENCY) {
		err = ops->adjfreq(ops, scaled_ppm_to_ppb(tx->freq));
		s32 ppb = scaled_ppm_to_ppb(tx->freq);
		if (ppb > ops->max_adj \|\| ppb < -ops->max_adj)
		return -ERANGE;
		err = ops->adjfreq(ops, ppb);
		ptp->dialed_frequency = tx->freq;
		} else if (tx->modes == 0) {
		tx->freq = ptp->dialed_frequency;

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