firmware: arm_scmi: Harden accesses to the reset domains

Accessing reset domains descriptors by the index upon the SCMI drivers
requests through the SCMI reset operations interface can potentially
lead to out-of-bound violations if the SCMI driver misbehave.

Add an internal consistency check before any such domains descriptors
accesses.

Link: https://lore.kernel.org/r/20220817172731.1185305-5-cristian.marussi@arm.com
Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

diff --git a/drivers/firmware/arm_scmi/reset.c b/drivers/firmware/arm_scmi/reset.c
index 673f3eb..b049416 100644 (file)
--- a/drivers/firmware/arm_scmi/reset.c
+++ b/drivers/firmware/arm_scmi/reset.c
@@ -166,8 +166,12 @@ static int scmi_domain_reset(const struct scmi_protocol_handle *ph, u32 domain,
        struct scmi_xfer *t;
        struct scmi_msg_reset_domain_reset *dom;
        struct scmi_reset_info *pi = ph->get_priv(ph);
-       struct reset_dom_info *rdom = pi->dom_info + domain;
+       struct reset_dom_info *rdom;
 
+       if (domain >= pi->num_domains)
+               return -EINVAL;
+
+       rdom = pi->dom_info + domain;
        if (rdom->async_reset)
                flags |= ASYNCHRONOUS_RESET;