firmware: arm_scpi: Fix string overflow in SCPI genpd driver

stable inclusion
from stable-v4.19.222
commit 7e8645ca2c0046f7cd2f0f7d569fc036c8abaedb
category: bugfix
bugzilla: https://gitee.com/src-openeuler/kernel/issues/IA6SID
CVE: CVE-2021-47609

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=7e8645ca2c0046f7cd2f0f7d569fc036c8abaedb



--------------------------------

commit 865ed67a upstream.

Without the bound checks for scpi_pd->name, it could result in the buffer
overflow when copying the SCPI device name from the corresponding device
tree node as the name string is set at maximum size of 30.

Let us fix it by using devm_kasprintf so that the string buffer is
allocated dynamically.

Fixes: 8bec4337 ("firmware: scpi: add device power domain support using genpd")
Reported-by: Pedro Batista <pedbap.g@gmail.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Cc: stable@vger.kernel.org
Cc: Cristian Marussi <cristian.marussi@arm.com>
Link: https://lore.kernel.org/r/20211209120456.696879-1-sudeep.holla@arm.com

'
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Yi Yang <yiyang13@huawei.com>