ARM: 9290/1: uaccess: Fix KASAN false-positives

__copy_to_user_memcpy() and __clear_user_memset() had been calling
memcpy() and memset() respectively, leading to false-positive KASAN
reports when starting userspace:

    [   10.707901] Run /init as init process
    [   10.731892] process '/bin/busybox' started with executable stack
    [   10.745234] ==================================================================
    [   10.745796] BUG: KASAN: user-memory-access in __clear_user_memset+0x258/0x3ac
    [   10.747260] Write of size 2687 at addr 000de581 by task init/1

Use __memcpy() and __memset() instead to allow userspace access, which
is of course the intent of these functions.

Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
Signed-off-by: Zev Weiss <zev@bewilderbeest.net>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>

diff --git a/arch/arm/lib/uaccess_with_memcpy.c b/arch/arm/lib/uaccess_with_memcpy.c
index 14eecaa..e4c2677 100644 (file)
--- a/arch/arm/lib/uaccess_with_memcpy.c
+++ b/arch/arm/lib/uaccess_with_memcpy.c
@@ -116,7 +116,7 @@ __copy_to_user_memcpy(void __user *to, const void *from, unsigned long n)
                        tocopy = n;
 
                ua_flags = uaccess_save_and_enable();
-               memcpy((void *)to, from, tocopy);
+               __memcpy((void *)to, from, tocopy);
                uaccess_restore(ua_flags);
                to += tocopy;
                from += tocopy;
@@ -178,7 +178,7 @@ __clear_user_memset(void __user *addr, unsigned long n)
                        tocopy = n;
 
                ua_flags = uaccess_save_and_enable();
-               memset((void *)addr, 0, tocopy);
+               __memset((void *)addr, 0, tocopy);
                uaccess_restore(ua_flags);
                addr += tocopy;
                n -= tocopy;