From: Cristian Marussi cristian.marussi@arm.com
[ Upstream commit 8009120e0354a67068e920eb10dce532391361d0 ]
While enumerating protocols implemented by the SCMI platform using BASE_DISCOVER_LIST_PROTOCOLS, the number of returned protocols is currently validated in an improper way since the check employs a sum between unsigned integers that could overflow and cause the check itself to be silently bypassed if the returned value 'loop_num_ret' is big enough.
Fix the validation avoiding the addition.
Link: https://lore.kernel.org/r/20220330150551.2573938-4-cristian.marussi@arm.com Fixes: b6f20ff8bd94 ("firmware: arm_scmi: add common infrastructure and support for base protocol") Signed-off-by: Cristian Marussi cristian.marussi@arm.com Signed-off-by: Sudeep Holla sudeep.holla@arm.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/firmware/arm_scmi/base.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/firmware/arm_scmi/base.c b/drivers/firmware/arm_scmi/base.c index 017e5d8bd869..e51d28ba2833 100644 --- a/drivers/firmware/arm_scmi/base.c +++ b/drivers/firmware/arm_scmi/base.c @@ -188,7 +188,7 @@ static int scmi_base_implementation_list_get(const struct scmi_handle *handle, break;
loop_num_ret = le32_to_cpu(*num_ret); - if (tot_num_ret + loop_num_ret > MAX_PROTOCOLS_IMP) { + if (loop_num_ret > MAX_PROTOCOLS_IMP - tot_num_ret) { dev_err(dev, "No. of Protocol > MAX_PROTOCOLS_IMP"); break; }