ipmi_si: fix potential integer overflow on large shift
[ Upstream commit
97a103e6b584442cd848887ed8d47be2410b7e09 ]
Shifting unsigned char b by an int type can lead to sign-extension
overflow. For example, if b is 0xff and the shift is 24, then top
bit is sign-extended so the final value passed to writeq has all
the upper 32 bits set. Fix this by casting b to a 64 bit unsigned
before the shift.
Detected by CoverityScan, CID#1465246 ("Unintended sign extension")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Corey Minyard <cminyard@mvista.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>