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[SRU,J,1/2] firmware: arm_scmi: Fix chan_free cleanup on SMC

Message ID 20240910023754.2163657-2-hui.wang@canonical.com
State New
Headers show
Series CVE-2024-26893 | expand

Commit Message

Hui Wang Sept. 10, 2024, 2:37 a.m. UTC 
From: Cristian Marussi <cristian.marussi@arm.com>

SCMI transport based on SMC can optionally use an additional IRQ to
signal message completion. The associated interrupt handler is currently
allocated using devres but on shutdown the core SCMI stack will call
.chan_free() well before any managed cleanup is invoked by devres.
As a consequence, the arrival of a late reply to an in-flight pending
transaction could still trigger the interrupt handler well after the
SCMI core has cleaned up the channels, with unpleasant results.

Inhibit further message processing on the IRQ path by explicitly freeing
the IRQ inside .chan_free() callback itself.

Fixes: dd820ee21d5e ("firmware: arm_scmi: Augment SMC/HVC to allow optional interrupt")
Reported-by: Bjorn Andersson <andersson@kernel.org>
Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
Link: https://lore.kernel.org/r/20230719173533.2739319-1-cristian.marussi@arm.com
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
(cherry picked from commit d1ff11d7ad8704f8d615f6446041c221b2d2ec4d)
CVE-2024-26893
Signed-off-by: Hui Wang <hui.wang@canonical.com>
---
 drivers/firmware/arm_scmi/smc.c | 17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)
diff mbox series

Patch

diff --git a/drivers/firmware/arm_scmi/smc.c b/drivers/firmware/arm_scmi/smc.c
index ea1caf70e8df9..cbe025d4cb612 100644
--- a/drivers/firmware/arm_scmi/smc.c
+++ b/drivers/firmware/arm_scmi/smc.c
@@ -21,6 +21,7 @@ 
 /**
  * struct scmi_smc - Structure representing a SCMI smc transport
  *
+ * @irq: An optional IRQ for completion
  * @cinfo: SCMI channel info
  * @shmem: Transmit/Receive shared memory area
  * @shmem_lock: Lock to protect access to Tx/Rx shared memory area
@@ -30,6 +31,7 @@ 
  */
 
 struct scmi_smc {
+	int irq;
 	struct scmi_chan_info *cinfo;
 	struct scmi_shared_mem __iomem *shmem;
 	struct mutex shmem_lock;
@@ -66,7 +68,7 @@  static int smc_chan_setup(struct scmi_chan_info *cinfo, struct device *dev,
 	struct resource res;
 	struct device_node *np;
 	u32 func_id;
-	int ret, irq;
+	int ret;
 
 	if (!tx)
 		return -ENODEV;
@@ -104,11 +106,10 @@  static int smc_chan_setup(struct scmi_chan_info *cinfo, struct device *dev,
 	 * completion of a message is signaled by an interrupt rather than by
 	 * the return of the SMC call.
 	 */
-	irq = of_irq_get_byname(cdev->of_node, "a2p");
-	if (irq > 0) {
-		ret = devm_request_irq(dev, irq, smc_msg_done_isr,
-				       IRQF_NO_SUSPEND,
-				       dev_name(dev), scmi_info);
+	scmi_info->irq = of_irq_get_byname(cdev->of_node, "a2p");
+	if (scmi_info->irq > 0) {
+		ret = request_irq(scmi_info->irq, smc_msg_done_isr,
+				  IRQF_NO_SUSPEND, dev_name(dev), scmi_info);
 		if (ret) {
 			dev_err(dev, "failed to setup SCMI smc irq\n");
 			return ret;
@@ -130,6 +131,10 @@  static int smc_chan_free(int id, void *p, void *data)
 	struct scmi_chan_info *cinfo = p;
 	struct scmi_smc *scmi_info = cinfo->transport_info;
 
+	/* Ignore any possible further reception on the IRQ path */
+	if (scmi_info->irq > 0)
+		free_irq(scmi_info->irq, scmi_info);
+
 	cinfo->transport_info = NULL;
 	scmi_info->cinfo = NULL;