sparc: fix ldom_reboot buffer overflow harder

The length argument to strlcpy was still wrong. It could overflow the end of
full_boot_str by 5 bytes. Instead of strcat and strlcpy, just use snprint.

Reported-by: Brad Spengler <spender@grsecurity.net>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/arch/sparc/kernel/ds.c b/arch/sparc/kernel/ds.c
index 4d9ac84..dff60ab 100644 (file)
--- a/arch/sparc/kernel/ds.c
+++ b/arch/sparc/kernel/ds.c
@@ -849,9 +849,8 @@ void ldom_reboot(const char *boot_command)
        if (boot_command && strlen(boot_command)) {
                unsigned long len;
 
-               strcpy(full_boot_str, "boot ");
-               strlcpy(full_boot_str + strlen("boot "), boot_command,
-                       sizeof(full_boot_str));
+               snprintf(full_boot_str, sizeof(full_boot_str), "boot %s",
+                        boot_command);
                len = strlen(full_boot_str);
 
                if (reboot_data_supported) {