MIPS: Loongson: Fix potentially wrong string handling

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.

Signed-off-by: Stefan Weil <weil@mail.berlios.de>
Cc: Wu Zhangjin <wuzhangjin@gmail.com>
Cc: Arnaud Patard <apatard@mandriva.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/2053/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

diff --git a/arch/mips/loongson/common/machtype.c b/arch/mips/loongson/common/machtype.c
index 81fbe6b73f91f71b896292cbf55b7b1c67990f80..2efd5d9dee27192f8a0da79698eb79b5c6e9828c 100644 (file)
--- 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';