[PATCH v7 06/38] kmsan: Fix kmsan_copy_to_user() on arches with overlapping address spaces
From: Ilya Leoshkevich <iii@linux.ibm.com>
Date: 2024-06-21 11:37:38
Also in:
linux-s390, lkml
Subsystem:
kmsan, memory management, the rest · Maintainers:
Alexander Potapenko, Andrew Morton, Linus Torvalds
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. Reported-by: Alexander Gordeev <agordeev@linux.ibm.com> Reviewed-by: Alexander Potapenko <glider@google.com> Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com> --- 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);
--
2.45.1