[PATCH v2 25/26] media: dvb-frontends: tda10048: Fix integer overflow

[Ricardo Ribalda]

state->xtal_hz can be up to 16M, so it can overflow a 32 bit integer
when multiplied by pll_mfactor.

Create a new 64 bit variable to hold the calculations.

Reported-by: Dan Carpenter <dan.carpenter at linaro.org>
Signed-off-by: Ricardo Ribalda <ribalda at chromium.org>
---
 drivers/media/dvb-frontends/tda10048.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/media/dvb-frontends/tda10048.c b/drivers/media/dvb-frontends/tda10048.c
index 5d5e4e9e4422..3e725cdcc66b 100644
--- a/drivers/media/dvb-frontends/tda10048.c
+++ b/drivers/media/dvb-frontends/tda10048.c
@@ -410,6 +410,7 @@ static int tda10048_set_if(struct dvb_frontend *fe, u32 bw)
 	struct tda10048_config *config = &state->config;
 	int i;
 	u32 if_freq_khz;
+	u64 sample_freq;
 
 	dprintk(1, "%s(bw = %d)\n", __func__, bw);
 
@@ -451,9 +452,11 @@ static int tda10048_set_if(struct dvb_frontend *fe, u32 bw)
 	dprintk(1, "- pll_pfactor = %d\n", state->pll_pfactor);
 
 	/* Calculate the sample frequency */
-	state->sample_freq = state->xtal_hz * (state->pll_mfactor + 45);
-	state->sample_freq /= (state->pll_nfactor + 1);
-	state->sample_freq /= (state->pll_pfactor + 4);
+	sample_freq = state->xtal_hz;
+	sample_freq *= state->pll_mfactor + 45;
+	do_div(sample_freq, state->pll_nfactor + 1);
+	do_div(sample_freq, state->pll_pfactor + 4);
+	state->sample_freq = sample_freq;
 	dprintk(1, "- sample_freq = %d\n", state->sample_freq);
 
 	/* Update the I/F */

-- 
2.44.0.769.g3c40516874-goog