as reported by Coverity, if reading SNR registers fail, a negative
number will be returned, causing an underflow when reading SNR
registers.
Prevent that.
Fixes: 8953db793d5b ("V4L/DVB (9178): cx24116: Add module parameter to return SNR as ESNO.")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@xxxxxxxxxx>
---
drivers/media/dvb-frontends/cx24116.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/drivers/media/dvb-frontends/cx24116.c b/drivers/media/dvb-frontends/cx24116.c
index 8b978a9f74a4..f5dd3a81725a 100644
--- a/drivers/media/dvb-frontends/cx24116.c
+++ b/drivers/media/dvb-frontends/cx24116.c
@@ -741,6 +741,7 @@ static int cx24116_read_snr_pct(struct dvb_frontend *fe, u16 *snr)
{
struct cx24116_state *state = fe->demodulator_priv;
u8 snr_reading;
+ int ret;
static const u32 snr_tab[] = { /* 10 x Table (rounded up) */
0x00000, 0x0199A, 0x03333, 0x04ccD, 0x06667,
0x08000, 0x0999A, 0x0b333, 0x0cccD, 0x0e667,
@@ -749,7 +750,11 @@ static int cx24116_read_snr_pct(struct dvb_frontend *fe, u16 *snr)
dprintk("%s()\n", __func__);
- snr_reading = cx24116_readreg(state, CX24116_REG_QUALITY0);
+ ret = cx24116_readreg(state, CX24116_REG_QUALITY0);
+ if (ret < 0)
+ return ret;
+
+ snr_reading = ret;
if (snr_reading >= 0xa0 /* 100% */)
*snr = 0xffff;
--
2.47.0
