[PATCH] ASoC: cx2072x: fix integer overflow on unsigned int multiply

From: Colin Ian King
Date: Fri May 24 2019 - 18:25:51 EST


In the case where frac_div larger than 96 the result of an unsigned
multiplication overflows an unsigned int. For example, this can
happen when the sample_rate is 192000 and pll_input is 122. Fix
this by casing the first term of the mutiply to a u64. Also remove
the extraneous parentheses around the expression.

Addresses-Coverity: ("Unintentional integer overflow")
Fixes: a497a4363706 ("ASoC: Add support for Conexant CX2072X CODEC")
Signed-off-by: Colin Ian King <colin.king@xxxxxxxxxxxxx>
Reviewed-by: Takashi Iwai <tiwai@xxxxxxx>
Signed-off-by: Mark Brown <broonie@xxxxxxxxxx>
---
sound/soc/codecs/cx2072x.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sound/soc/codecs/cx2072x.c b/sound/soc/codecs/cx2072x.c
index c11a585bbf70..ed762546eaee 100644
--- a/sound/soc/codecs/cx2072x.c
+++ b/sound/soc/codecs/cx2072x.c
@@ -627,7 +627,7 @@ static int cx2072x_config_pll(struct cx2072x_priv *cx2072x)
if (frac_div) {
frac_div *= 1000;
frac_div /= pll_input;
- frac_num = ((4000 + frac_div) * ((1 << 20) - 4));
+ frac_num = (u64)(4000 + frac_div) * ((1 << 20) - 4);
do_div(frac_num, 7);
frac = ((u32)frac_num + 499) / 1000;
}
--
2.20.1