[PATCH] ARM: uaccess: Fix KASAN false-positives

[Zev Weiss]

From: Andrew Jeffery <andrew at aj.id.au>

__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 at aj.id.au>
Signed-off-by: Zev Weiss <zev at bewilderbeest.net>
---
 arch/arm/lib/uaccess_with_memcpy.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/arm/lib/uaccess_with_memcpy.c b/arch/arm/lib/uaccess_with_memcpy.c
index 14eecaaf295f..e4c2677cc1e9 100644
--- 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;
-- 
2.39.1.438.g79fd386332e5.dirty