From f926e9326f3a79f7e01ac790e2361f44d8ca8320 Mon Sep 17 00:00:00 2001 From: Ilya Leoshkevich Date: Fri, 21 Jun 2024 13:34:50 +0200 Subject: [PATCH] kmsan: fix kmsan_copy_to_user() on arches with overlapping address spaces Comparing pointers with TASK_SIZE does not make sense when kernel and userspace overlap. Assume that we are handling user memory access in this case. Link: https://lkml.kernel.org/r/20240621113706.315500-7-iii@linux.ibm.com Signed-off-by: Ilya Leoshkevich Reported-by: Alexander Gordeev Reviewed-by: Alexander Potapenko Cc: Christian Borntraeger Cc: Christoph Lameter Cc: David Rientjes Cc: Dmitry Vyukov Cc: Heiko Carstens Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com> Cc: Joonsoo Kim Cc: Cc: Marco Elver Cc: Mark Rutland Cc: Masami Hiramatsu (Google) Cc: Pekka Enberg Cc: Roman Gushchin Cc: Steven Rostedt (Google) Cc: Sven Schnelle Cc: Vasily Gorbik Cc: Vlastimil Babka Signed-off-by: Andrew Morton --- mm/kmsan/hooks.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/mm/kmsan/hooks.c b/mm/kmsan/hooks.c index 22e8657800ef..b408714f9ba3 100644 --- a/mm/kmsan/hooks.c +++ b/mm/kmsan/hooks.c @@ -267,7 +267,8 @@ void kmsan_copy_to_user(void __user *to, const void *from, size_t to_copy, return; ua_flags = user_access_save(); - if ((u64)to < TASK_SIZE) { + if (!IS_ENABLED(CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE) || + (u64)to < TASK_SIZE) { /* This is a user memory access, check it. */ kmsan_internal_check_memory((void *)from, to_copy - left, to, REASON_COPY_TO_USER);