[PATCH v3] clk: scmi: fix invalid clock name references

[Etienne Carriere]

Fixes clock name references in scmi_clk driver. SCMI clock names are
retrieved from the SCMI firmware by invoking SCMI commands using the
stack for SCMI response message hence clocks names located in the
stack must be duplicated before being registered in the clock framework.

Fixes: 7c33f78983c3 ("clk: scmi: register scmi clocks with CCF")
Reported-by: scan-admin at coverity.com
Signed-off-by: Etienne Carriere <etienne.carriere at linaro.org>
---
Changes since v2:
- Remove duplicated allocation of SCMI clock names.

Changes since v1:
- Fix buggy test on strdup() return value
---
 drivers/clk/clk_scmi.c | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/drivers/clk/clk_scmi.c b/drivers/clk/clk_scmi.c
index 57022685e2..aa339f6af2 100644
--- a/drivers/clk/clk_scmi.c
+++ b/drivers/clk/clk_scmi.c
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0+
 /*
- * Copyright (C) 2019-2020 Linaro Limited
+ * Copyright (C) 2019-2022 Linaro Limited
  */
 
 #define LOG_CATEGORY UCLASS_CLK
@@ -12,6 +12,7 @@
 #include <scmi_protocols.h>
 #include <asm/types.h>
 #include <linux/clk-provider.h>
+#include <linux/string.h>
 
 static int scmi_clk_get_num_clock(struct udevice *dev, size_t *num_clocks)
 {
@@ -53,7 +54,9 @@ static int scmi_clk_get_attibute(struct udevice *dev, int clkid, char **name)
 	if (ret)
 		return ret;
 
-	*name = out.clock_name;
+	*name = strdup(out.clock_name);
+	if (!*name)
+		return -ENOMEM;
 
 	return 0;
 }
@@ -152,21 +155,20 @@ static int scmi_clk_probe(struct udevice *dev)
 		return ret;
 
 	for (i = 0; i < num_clocks; i++) {
+		/* Clock name is allocated from scmi_clk_get_attibute() */
 		char *name;
 
 		if (!scmi_clk_get_attibute(dev, i, &name)) {
-			char *clock_name = strdup(name);
-
 			clk = kzalloc(sizeof(*clk), GFP_KERNEL);
-			if (!clk || !clock_name)
+			if (!clk)
 				ret = -ENOMEM;
 			else
 				ret = clk_register(clk, dev->driver->name,
-						   clock_name, dev->name);
+						   name, dev->name);
 
 			if (ret) {
 				free(clk);
-				free(clock_name);
+				free(name);
 				return ret;
 			}
 
-- 
2.17.1