[PATCH] MIPS: Loongson: Fix potentially wrong string handling

[Stefan Weil]

This error was reported by cppcheck:
arch/mips/loongson/common/machtype.c:56: error: Dangerous usage of 'str' (strncpy doesn't always 0-terminate it)

If strncpy copied MACHTYPE_LEN bytes, the destination string str
was not terminated.

The patch adds one more byte to str and makes sure that this byte is
always 0.

Cc: Ralf Baechle <ralf@xxxxxxxxxxxxxx>
Cc: Wu Zhangjin <wuzhangjin@xxxxxxxxx>
Cc: Arnaud Patard <apatard@xxxxxxxxxxxx>
Cc: linux-mips@xxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
Signed-off-by: Stefan Weil <weil@xxxxxxxxxxxxxxx>
---
 arch/mips/loongson/common/machtype.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/arch/mips/loongson/common/machtype.c b/arch/mips/loongson/common/machtype.c
index 81fbe6b..2efd5d9 100644
--- a/arch/mips/loongson/common/machtype.c
+++ b/arch/mips/loongson/common/machtype.c
@@ -41,7 +41,7 @@ void __weak __init mach_prom_init_machtype(void)
 
 void __init prom_init_machtype(void)
 {
-	char *p, str[MACHTYPE_LEN];
+	char *p, str[MACHTYPE_LEN + 1];
 	int machtype = MACH_LEMOTE_FL2E;
 
 	mips_machtype = LOONGSON_MACHTYPE;
@@ -53,6 +53,7 @@ void __init prom_init_machtype(void)
 	}
 	p += strlen("machtype=");
 	strncpy(str, p, MACHTYPE_LEN);
+	str[MACHTYPE_LEN] = '\0';
 	p = strstr(str, " ");
 	if (p)
 		*p = '\0';
-- 
1.7.2.3

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