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authorColin Ian King <colin.king@canonical.com>2020-02-10 15:26:46 +0100
committerMauro Carvalho Chehab <mchehab+huawei@kernel.org>2020-03-12 09:46:45 +0100
commita7463e2dc698075132de9905b89f495df888bb79 (patch)
treedd753af56fb79a15c603667334ef9909c9776cbe /drivers/media
parent889968a4f76928ce08a607d576d6ffd7c3521925 (diff)
media: tda10071: fix unsigned sign extension overflow
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>
Diffstat (limited to 'drivers/media')
-rw-r--r--drivers/media/dvb-frontends/tda10071.c9
1 files changed, 5 insertions, 4 deletions
diff --git a/drivers/media/dvb-frontends/tda10071.c b/drivers/media/dvb-frontends/tda10071.c
index 1953b00b3e48..685c0ac71819 100644
--- a/drivers/media/dvb-frontends/tda10071.c
+++ b/drivers/media/dvb-frontends/tda10071.c
@@ -470,10 +470,11 @@ 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;