Re: [PATCH] firmware: arm_scmi: Relax BASE protocol sanity checks on protocol list
From: Etienne Carriere <hidden>
Date: 2022-05-31 14:59:50
Also in:
linux-rockchip, lkml
Hello Cristian, On Mon, 23 May 2022 at 19:17, Cristian Marussi [off-list ref] wrote:
Even though malformed replies from firmware must be treated carefully to avoid memory corruption Kernel side, some out-of-spec SCMI replies can be tolerated to avoid breaking existing deployed system, as long as they won't cause memory issues. Reported-by: Nicolas Frattaroli <frattaroli.nicolas@gmail.com> Cc: Etienne Carriere <redacted> Cc: Sudeep Holla <redacted> Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
Acked-by: Etienne Carriere <redacted> Best regards, etienne
quoted hunk ↗ jump to hunk
--- 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 20fba7370f4e..d0ac96da1ddf 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++) --2.36.1
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