Merge tag 'scmi-fixes-5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/sudeep.holla/linux into arm/fixes

Arm SCMI firmware driver fixes for v5.19

Bunch of fixes to address:
1. Issues reported on RK3568 EVB1 and BPI-R2 pro platforms using SCMI.
   More checks were added to validate the firmware response but that
   resulted in breaking above platforms, so the checks are relaxed when
   for cases where there is no potential memory corruption issues.

2. Possible data leak by reading more than required length from the firmware.
   Recent addition of support for v3.1 extended names used larger buffers
   in the kernel and used their size to read response from the firmware even
   for cases where shorter formats are used. While that is mostly harmless
   except when firmware sends malformed non-NULL terminated buffers.

3. Possible issues sending unsupported commands to the firmware.
   SENSOR_AXIS_NAME_GET added in v3.1 needs to be used only if the firmware
   supports it. While the firmware conformant to the spec must return not
   supported error for any unsupported features, it is always safer to
   avoid issuing commands that are known to be unsupported.

4. Incorrect error propagation in scmi_voltage_descriptors_get.
   Since the return value is not reset for each iteration of the loop, the
   error value in the previous iteration will be carried for the current one.
   Fix that by not saving the return values into local variable.

5. Some warnings reported by cppcheck

* tag 'scmi-fixes-5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/sudeep.holla/linux:
  firmware: arm_scmi: Fix incorrect error propagation in scmi_voltage_descriptors_get
  firmware: arm_scmi: Avoid using extended string-buffers sizes if not necessary
  firmware: arm_scmi: Fix SENSOR_AXIS_NAME_GET behaviour when unsupported
  firmware: arm_scmi: Remove all the unused local variables
  firmware: arm_scmi: Relax base protocol sanity checks on the protocol list

Link: https://lore.kernel.org/r/20220614100007.1029881-1-sudeep.holla@arm.com
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

1 files changed, 5 insertions, 4 deletions

diff --git a/include/linux/scmi_protocol.h b/include/linux/scmi_protocol.h
index 1c58646ba381..704111f63993 100644
--- a/include/linux/scmi_protocol.h
+++ b/include/linux/scmi_protocol.h
@@ -13,8 +13,9 @@
 #include <linux/notifier.h>
 #include <linux/types.h>
 
-#define SCMI_MAX_STR_SIZE	64
-#define SCMI_MAX_NUM_RATES	16
+#define SCMI_MAX_STR_SIZE		64
+#define SCMI_SHORT_NAME_MAX_SIZE	16
+#define SCMI_MAX_NUM_RATES		16
 
 /**
  * struct scmi_revision_info - version information structure
@@ -36,8 +37,8 @@ struct scmi_revision_info {
 	u8 num_protocols;
 	u8 num_agents;
 	u32 impl_ver;
-	char vendor_id[SCMI_MAX_STR_SIZE];
-	char sub_vendor_id[SCMI_MAX_STR_SIZE];
+	char vendor_id[SCMI_SHORT_NAME_MAX_SIZE];
+	char sub_vendor_id[SCMI_SHORT_NAME_MAX_SIZE];
 };
 
 struct scmi_clock_info {