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media: cx231xx: fix potential sign-extension overflow on large shift

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[ Upstream commit 32ae592036d7aeaabcccb2b1715373a68639a768 ]

Shifting the u8 value[3] by an int can lead to sign-extension
overflow. For example, if value[3] is 0xff and the shift is 24 then it
is promoted to int and then the top bit is sign-extended so that all
upper 32 bits are set.  Fix this by casting value[3] to a u32 before
the shift.

Detected by CoverityScan, CID#1016522 ("Unintended sign extension")

Fixes: e0d3bafd02 ("V4L/DVB (10954): Add cx231xx USB driver")

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Colin Ian King 2018-10-06 14:01:42 -04:00 • committed by Greg Kroah-Hartman
parent 560976f5b8
commit 0e74fb6274
1 changed files with 1 additions and 1 deletions
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2
drivers/media/usb/cx231xx/cx231xx-video.c
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@ -1346,7 +1346,7 @@ int cx231xx_g_register(struct file *file, void *priv,
ret = cx231xx_read_ctrl_reg(dev, VRT_GET_REGISTER,
(u16)reg->reg, value, 4);
reg->val = value[0] | value[1] << 8 |
value[2] << 16 | value[3] << 24;
value[2] << 16 | (u32)value[3] << 24;
reg->size = 4;
break;
case 1: /* AFE - read byte */