From: Yanjun Yang <yangyj.ee@gmail.com>
Date: Tue, 11 Jun 2024 10:09:47 +0000 (+0800)
Subject: ARM: Remove address checking for MMUless devices
X-Git-Tag: v6.6.86~21
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=ad0410346cc4edd76e7e51b5eb8f5cc795d5a0bc;p=thirdparty%2Fkernel%2Fstable.git

ARM: Remove address checking for MMUless devices

commit 3ccea4784fddd96fbd6c4497eb28b45dab638c2a upstream.

Commit 169f9102f9198b ("ARM: 9350/1: fault: Implement
copy_from_kernel_nofault_allowed()") added the function to check address
before use. However, for devices without MMU, addr > TASK_SIZE will
always fail.  This patch move this function after the #ifdef CONFIG_MMU
statement.

Signed-off-by: Yanjun Yang <yangyj.ee@gmail.com>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=218953
Fixes: 169f9102f9198b ("ARM: 9350/1: fault: Implement copy_from_kernel_nofault_allowed()")
Link: https://lore.kernel.org/r/20240611100947.32241-1-yangyj.ee@gmail.com
Signed-off-by: Kees Cook <kees@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/arch/arm/mm/fault.c b/arch/arm/mm/fault.c
index 33f03fb8d038b..ed1a25f457e48 100644
--- a/arch/arm/mm/fault.c
+++ b/arch/arm/mm/fault.c
@@ -25,6 +25,8 @@
 
 #include "fault.h"
 
+#ifdef CONFIG_MMU
+
 bool copy_from_kernel_nofault_allowed(const void *unsafe_src, size_t size)
 {
 	unsigned long addr = (unsigned long)unsafe_src;
@@ -32,8 +34,6 @@ bool copy_from_kernel_nofault_allowed(const void *unsafe_src, size_t size)
 	return addr >= TASK_SIZE && ULONG_MAX - addr >= size;
 }
 
-#ifdef CONFIG_MMU
-
 /*
  * This is useful to dump out the page tables associated with
  * 'addr' in mm 'mm'.