ARM: Remove address checking for MMUless devices

setarcos · kees · commit 3ccea4784fdd · 2024-07-09T08:53:59.000-07:00
Commit 169f910 ("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: 169f910 ("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>
diff --git a/arch/arm/mm/fault.c b/arch/arm/mm/fault.c
@@ -25,15 +25,15 @@
 
 #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;
 
 	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'.

Original file line number	Diff line number	Diff line change
`@@ -25,15 +25,15 @@`
`25`	`25`
`26`	`26`	`#include "fault.h"`
`27`	`27`
	`28`	`+#ifdef CONFIG_MMU`
	`29`	`+`
`28`	`30`	`bool copy_from_kernel_nofault_allowed(const void *unsafe_src, size_t size)`
`29`	`31`	`{`
`30`	`32`	`unsigned long addr = (unsigned long)unsafe_src;`
`31`	`33`
`32`	`34`	`return addr >= TASK_SIZE && ULONG_MAX - addr >= size;`
`33`	`35`	`}`
`34`	`36`
`35`		`-#ifdef CONFIG_MMU`
`36`		`-`
`37`	`37`	`/*`
`38`	`38`	`* This is useful to dump out the page tables associated with`
`39`	`39`	`* 'addr' in mm 'mm'.`