From: Sudeep Holla sudeep.holla@arm.com
stable inclusion from linux-4.19.200 commit edb6f5a95a0c7cdd40c91db952a63c915375e876
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[ Upstream commit 7a691f16ccad05d770f813d9c4b4337a30c6d63f ]
The scmi_linux_errmap buffer access index is supposed to depend on the array size to prevent element out of bounds access. It uses SCMI_ERR_MAX to check bounds but that can mismatch with the array size. It also changes the success into -EIO though scmi_linux_errmap is never used in case of success, it is expected to work for success case too.
It is slightly confusing code as the negative of the error code is used as index to the buffer. Fix it by negating it at the start and make it more readable.
Link: https://lore.kernel.org/r/20210707135028.1869642-1-sudeep.holla@arm.com Reported-by: kernel test robot lkp@intel.com Reported-by: Dan Carpenter dan.carpenter@oracle.com Reviewed-by: Cristian Marussi cristian.marussi@arm.com Signed-off-by: Sudeep Holla sudeep.holla@arm.com Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- drivers/firmware/arm_scmi/driver.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/drivers/firmware/arm_scmi/driver.c b/drivers/firmware/arm_scmi/driver.c index effc4c17e0fb9..081fbe28da4be 100644 --- a/drivers/firmware/arm_scmi/driver.c +++ b/drivers/firmware/arm_scmi/driver.c @@ -48,7 +48,6 @@ enum scmi_error_codes { SCMI_ERR_GENERIC = -8, /* Generic Error */ SCMI_ERR_HARDWARE = -9, /* Hardware Error */ SCMI_ERR_PROTOCOL = -10,/* Protocol Error */ - SCMI_ERR_MAX };
/* List of all SCMI devices active in system */ @@ -168,8 +167,10 @@ static const int scmi_linux_errmap[] = {
static inline int scmi_to_linux_errno(int errno) { - if (errno < SCMI_SUCCESS && errno > SCMI_ERR_MAX) - return scmi_linux_errmap[-errno]; + int err_idx = -errno; + + if (err_idx >= SCMI_SUCCESS && err_idx < ARRAY_SIZE(scmi_linux_errmap)) + return scmi_linux_errmap[err_idx]; return -EIO; }