firmware: arm_scmi: Harden accesses to the reset domains

commit e9076ffbcaed5da6c182b144ef9f6e24554af268 upstream.

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>
Signed-off-by: Dominique Martinet <dominique.martinet@atmark-techno.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/firmware/arm_scmi/reset.c b/drivers/firmware/arm_scmi/reset.c
index 6d223f345b6c97ee7b36bf9b8b43c41cc58ebefb..b45d3e9cee12983c3e8419c5182cef60b48137e6 100644 (file)
--- a/drivers/firmware/arm_scmi/reset.c
+++ b/drivers/firmware/arm_scmi/reset.c
@@ -135,8 +135,12 @@ static int scmi_domain_reset(const struct scmi_handle *handle, u32 domain,
        struct scmi_xfer *t;
        struct scmi_msg_reset_domain_reset *dom;
        struct scmi_reset_info *pi = handle->reset_priv;
-       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;