2024-04-29 15:12:58

by Ricardo Ribalda

[permalink] [raw]
Subject: [PATCH v3 25/26] media: dvb-frontends: tda10048: Fix integer overflow

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 <[email protected]>
Signed-off-by: Ricardo Ribalda <[email protected]>
---
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