From 77ed7a2ac975e4b72a1bd87e5c475c08c23bb06a Mon Sep 17 00:00:00 2001
From: Yuichiro Goto <goto@k-tech.co.jp>
Date: Mon, 26 Apr 2021 08:08:03 +0900
Subject: [PATCH] IOMUX: Fix buffer overflow in iomux_replace_device()

Use of strcat() against an uninitialized buffer would lead
to buffer overflow. This patch fixes it.

Fixes: 694cd5618c ("IOMUX: Introduce iomux_replace_device()")
Signed-off-by: Yuichiro Goto <goto@k-tech.co.jp>
Cc: Peter Robinson <pbrobinson@gmail.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Tested-by: Peter Robinson <pbrobinson@gmail.com>
---
 common/iomux.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/common/iomux.c b/common/iomux.c
index b9088aa3b5..c428f7110a 100644
--- a/common/iomux.c
+++ b/common/iomux.c
@@ -158,8 +158,12 @@ int iomux_replace_device(const int console, const char *old, const char *new)
 			return -ENOMEM;
 		}
 
-		strcat(tmp, ",");
-		strcat(tmp, name);
+		if (arg) {
+			strcat(tmp, ",");
+			strcat(tmp, name);
+		}
+		else
+			strcpy(tmp, name);
 
 		arg = tmp;
 		size = strlen(tmp) + 1;