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Date: Thu, 3 Dec 2015 15:46:48 -0500 From: Sasha Levin <sasha.levin@...cle.com> To: john.stultz@...aro.org, tglx@...utronix.de Cc: linux-kernel@...r.kernel.org, Sasha Levin <sasha.levin@...cle.com> Subject: [PATCH] ntp: verify offset doesn't overflow in ntp_update_offset We need to make sure that the offset is valid before manipulating it, otherwise it might overflow on the multiplication. Signed-off-by: Sasha Levin <sasha.levin@...cle.com> --- kernel/time/ntp.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c index 149cc80..36616c3 100644 --- a/kernel/time/ntp.c +++ b/kernel/time/ntp.c @@ -297,6 +297,9 @@ static void ntp_update_offset(long offset) if (!(time_status & STA_PLL)) return; + /* Make sure the multiplication below won't overflow */ + offset = clamp(offset, -MAXPHASE, MAXPHASE); + if (!(time_status & STA_NANO)) offset *= NSEC_PER_USEC; @@ -304,8 +307,7 @@ static void ntp_update_offset(long offset) * Scale the phase adjustment and * clamp to the operating range. */ - offset = min(offset, MAXPHASE); - offset = max(offset, -MAXPHASE); + offset = clamp(offset, -MAXPHASE, MAXPHASE); /* * Select how the frequency is to be controlled -- 1.7.10.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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