From 51a8f136adc99db604c50a545328e0fa5047e472 Mon Sep 17 00:00:00 2001 From: Cristian Marussi Date: Tue, 7 Mar 2023 16:23:24 +0000 Subject: [PATCH] firmware: arm_scmi: Fix device node validation for mailbox transport commit 2ab4f4018cb6b8010ca5002c3bdc37783b5d28c2 upstream. When mailboxes are used as a transport it is possible to setup the SCMI transport layer, depending on the underlying channels configuration, to use one or two mailboxes, associated, respectively, to one or two, distinct, shared memory areas: any other combination should be treated as invalid. Add more strict checking of SCMI mailbox transport device node descriptors. Fixes: 5c8a47a5a91d ("firmware: arm_scmi: Make scmi core independent of the transport type") Cc: # 4.19 Signed-off-by: Cristian Marussi Link: https://lore.kernel.org/r/20230307162324.891866-1-cristian.marussi@arm.com Signed-off-by: Sudeep Holla [Cristian: backported to v4.19] Signed-off-by: Cristian Marussi Signed-off-by: Greg Kroah-Hartman --- drivers/firmware/arm_scmi/driver.c | 37 ++++++++++++++++++++++++++++++ 1 file changed, 37 insertions(+) diff --git a/drivers/firmware/arm_scmi/driver.c b/drivers/firmware/arm_scmi/driver.c index e8cd66705ad7..5ccbbb3eb68e 100644 --- a/drivers/firmware/arm_scmi/driver.c +++ b/drivers/firmware/arm_scmi/driver.c @@ -705,6 +705,39 @@ static int scmi_remove(struct platform_device *pdev) return ret; } +static int scmi_mailbox_chan_validate(struct device *cdev) +{ + int num_mb, num_sh, ret = 0; + struct device_node *np = cdev->of_node; + + num_mb = of_count_phandle_with_args(np, "mboxes", "#mbox-cells"); + num_sh = of_count_phandle_with_args(np, "shmem", NULL); + /* Bail out if mboxes and shmem descriptors are inconsistent */ + if (num_mb <= 0 || num_sh > 2 || num_mb != num_sh) { + dev_warn(cdev, "Invalid channel descriptor for '%s'\n", + of_node_full_name(np)); + return -EINVAL; + } + + if (num_sh > 1) { + struct device_node *np_tx, *np_rx; + + np_tx = of_parse_phandle(np, "shmem", 0); + np_rx = of_parse_phandle(np, "shmem", 1); + /* SCMI Tx and Rx shared mem areas have to be distinct */ + if (!np_tx || !np_rx || np_tx == np_rx) { + dev_warn(cdev, "Invalid shmem descriptor for '%s'\n", + of_node_full_name(np)); + ret = -EINVAL; + } + + of_node_put(np_tx); + of_node_put(np_rx); + } + + return ret; +} + static inline int scmi_mbox_chan_setup(struct scmi_info *info, struct device *dev, int prot_id) { @@ -720,6 +753,10 @@ scmi_mbox_chan_setup(struct scmi_info *info, struct device *dev, int prot_id) goto idr_alloc; } + ret = scmi_mailbox_chan_validate(dev); + if (ret) + return ret; + cinfo = devm_kzalloc(info->dev, sizeof(*cinfo), GFP_KERNEL); if (!cinfo) return -ENOMEM;