[PATCH AUTOSEL 5.15 03/20] firmware: arm_scmi: Harden accesses to the reset domains

[Sasha Levin]

From: Cristian Marussi <cristian.marussi@xxxxxxx>

[ Upstream commit e9076ffbcaed5da6c182b144ef9f6e24554af268 ]

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@xxxxxxx
Signed-off-by: Cristian Marussi <cristian.marussi@xxxxxxx>
Signed-off-by: Sudeep Holla <sudeep.holla@xxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/firmware/arm_scmi/reset.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/firmware/arm_scmi/reset.c b/drivers/firmware/arm_scmi/reset.c
index 9bf2478ec6d1..fc6237d6e926 100644
--- a/drivers/firmware/arm_scmi/reset.c
+++ b/drivers/firmware/arm_scmi/reset.c
@@ -152,8 +152,12 @@ 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;
 
-- 
2.35.1