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Patch "arm64: fix CONFIG_DEBUG_WX address reporting" has been added to the 4.14-stable tree

PATCH [email protected] 1 participant 1 message Dec 18, 2017

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This is a note to let you know that I've just added the patch titled

arm64: fix CONFIG_DEBUG_WX address reporting

to the 4.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
arm64-fix-config_debug_wx-address-reporting.patch
and it can be found in the queue-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

Quoted 1 line

From 1d08a044cf12aee37dfd54837558e3295287b343 Mon Sep 17 00:00:00 2001

From: Mark Rutland <[email protected]>
Date: Wed, 13 Dec 2017 11:45:42 +0000
Subject: arm64: fix CONFIG_DEBUG_WX address reporting

From: Mark Rutland <[email protected]>

commit 1d08a044cf12aee37dfd54837558e3295287b343 upstream.

In ptdump_check_wx(), we pass walk_pgd() a start address of 0 (rather than VA_START) for the init_mm. This means that any reported W&X addresses are offset by VA_START, which is clearly wrong and can make them appear like userspace addresses.

Fix this by telling the ptdump code that we're walking init_mm starting at VA_START. We don't need to update the addr_markers, since these are still valid bounds regardless.

Fixes 1404d6f13e47 ("arm64: dump: Add checking for writable and exectuable pages")
Cc Kees Cook <[email protected]>
Cc Laura Abbott <[email protected]>
---
 arch/arm64/mm/dump.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
arch/arm64/mm/dump.c +1 -1
@@ -389,7 +389,7 @@ void ptdump_check_wx(void)
 		.check_wx = true,
 	};
 
-	walk_pgd(&st, &init_mm, 0);
+	walk_pgd(&st, &init_mm, VA_START);
 	note_page(&st, 0, 0, 0);
 	if (st.wx_pages || st.uxn_pages)
 		pr_warn("Checked W+X mappings: FAILED, %lu W+X pages found, %lu non-UXN pages found\n",

Patches currently in stable-queue which might be from [email protected] are

queue-4.14/arm64-fix-config_debug_wx-address-reporting.patch