media: tda10071: fix unsigned sign extension overflow
[ Upstream commit5.4-rM2-2.2.x-imx-squasheda7463e2dc6
] 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:267897a470
("[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>
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@ -470,10 +470,11 @@ static int tda10071_read_status(struct dvb_frontend *fe, enum fe_status *status)
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goto error;
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if (dev->delivery_system == SYS_DVBS) {
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dev->dvbv3_ber = buf[0] << 24 | buf[1] << 16 |
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buf[2] << 8 | buf[3] << 0;
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dev->post_bit_error += buf[0] << 24 | buf[1] << 16 |
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buf[2] << 8 | buf[3] << 0;
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u32 bit_error = buf[0] << 24 | buf[1] << 16 |
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buf[2] << 8 | buf[3] << 0;
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dev->dvbv3_ber = bit_error;
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dev->post_bit_error += bit_error;
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c->post_bit_error.stat[0].scale = FE_SCALE_COUNTER;
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c->post_bit_error.stat[0].uvalue = dev->post_bit_error;
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dev->block_error += buf[4] << 8 | buf[5] << 0;
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