From 122839b58a089ff7f231759e2c8f63790724cae2 Mon Sep 17 00:00:00 2001 From: Cristian Marussi Date: Mon, 23 May 2022 18:15:59 +0100 Subject: [PATCH] firmware: arm_scmi: Relax base protocol sanity checks on the protocol list Even though malformed replies from firmware must be treated carefully to avoid memory corruption in the kernel, some out-of-spec SCMI replies can be tolerated to avoid breaking existing deployed system, as long as they won't cause memory issues. Relax the sanity checks on the recieved protocol list in the base protocol to avoid breaking one of the deployed platform whose firmware is not easily upgradable currently. Link: https://lore.kernel.org/r/20220523171559.472112-1-cristian.marussi@arm.com Cc: Etienne Carriere Cc: Sudeep Holla Reported-by: Nicolas Frattaroli Tested-By: Frank Wunderlich Acked-by: Michael Riesch Acked-by: Etienne Carriere Signed-off-by: Cristian Marussi Signed-off-by: Sudeep Holla --- drivers/firmware/arm_scmi/base.c | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-) diff --git a/drivers/firmware/arm_scmi/base.c b/drivers/firmware/arm_scmi/base.c index 20fba7370f4e5..d0ac96da1ddff 100644 --- a/drivers/firmware/arm_scmi/base.c +++ b/drivers/firmware/arm_scmi/base.c @@ -221,11 +221,17 @@ scmi_base_implementation_list_get(const struct scmi_protocol_handle *ph, calc_list_sz = (1 + (loop_num_ret - 1) / sizeof(u32)) * sizeof(u32); if (calc_list_sz != real_list_sz) { - dev_err(dev, - "Malformed reply - real_sz:%zd calc_sz:%u\n", - real_list_sz, calc_list_sz); - ret = -EPROTO; - break; + dev_warn(dev, + "Malformed reply - real_sz:%zd calc_sz:%u (loop_num_ret:%d)\n", + real_list_sz, calc_list_sz, loop_num_ret); + /* + * Bail out if the expected list size is bigger than the + * total payload size of the received reply. + */ + if (calc_list_sz > real_list_sz) { + ret = -EPROTO; + break; + } } for (loop = 0; loop < loop_num_ret; loop++) -- 2.30.2