diff options
| author | Colin Ian King <colin.king@canonical.com> | 2020-02-10 15:26:46 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-10-01 11:11:53 +0200 |
| commit | d807d04a0e9ff0a9867064957fb7eb131ae7220c (patch) | |
| tree | 70e171791387ba623fdd5f842dd00699991c28b3 | |
| parent | 4ad03ff6f680681c5f78254e37c4c856fa953629 (diff) | |
media: tda10071: fix unsigned sign extension overflow
[ Upstream commit a7463e2dc698075132de9905b89f495df888bb79 ]
The shifting of buf[3] by 24 bits to the left will be promoted to
a 32 bit signed int and then sign-extended to an unsigned long. In
the unlikely event that the the top bit of buf[3] is set then all
then all the upper bits end up as also being set because of
the sign-extension and this affect the ev->post_bit_error sum.
Fix this by using the temporary u32 variable bit_error to avoid
the sign-extension promotion. This also removes the need to do the
computation twice.
Addresses-Coverity: ("Unintended sign extension")
Fixes: 267897a4708f ("[media] tda10071: implement DVBv5 statistics")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Sean Young <sean@mess.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -rw-r--r-- | drivers/media/dvb-frontends/tda10071.c | 9 |
1 files changed, 5 insertions, 4 deletions
diff --git a/drivers/media/dvb-frontends/tda10071.c b/drivers/media/dvb-frontends/tda10071.c index 119d47596ac8..b81887c4f72a 100644 --- a/drivers/media/dvb-frontends/tda10071.c +++ b/drivers/media/dvb-frontends/tda10071.c @@ -483,10 +483,11 @@ static int tda10071_read_status(struct dvb_frontend *fe, enum fe_status *status) goto error; if (dev->delivery_system == SYS_DVBS) { - dev->dvbv3_ber = buf[0] << 24 | buf[1] << 16 | - buf[2] << 8 | buf[3] << 0; - dev->post_bit_error += buf[0] << 24 | buf[1] << 16 | - buf[2] << 8 | buf[3] << 0; + u32 bit_error = buf[0] << 24 | buf[1] << 16 | + buf[2] << 8 | buf[3] << 0; + + dev->dvbv3_ber = bit_error; + dev->post_bit_error += bit_error; c->post_bit_error.stat[0].scale = FE_SCALE_COUNTER; c->post_bit_error.stat[0].uvalue = dev->post_bit_error; dev->block_error += buf[4] << 8 | buf[5] << 0; |