linux-kernel - [PATCH 5/6] yx86/efi: fixup faults from UEFI firmware

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <1410633376-8822-6-git-send-email-ricardo.neri-calderon@linux.intel.com>
Date:	Sat, 13 Sep 2014 11:36:15 -0700
From:	Ricardo Neri <ricardo.neri-calderon@...ux.intel.com>
To:	Matt Fleming <matt.fleming@...el.com>
Cc:	"H. Peter Anvin" <hpa@...ux.intel.com>, linux-efi@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	"Glenn P. Williamson" <glenn.p.williamson@...el.com>,
	Ricardo Neri <ricardo.neri-calderon@...ux.intel.com>
Subject: [PATCH 5/6] yx86/efi: fixup faults from UEFI firmware

Buggy UEFI firmware implementations may try to access the
EFI_BOOT_SERVICES_* memory regions even after those regions have been
surrendered to the kernel (after calling ExitBootServices() on the
firmware). If such regions are not mapped, a page fault will be
generated. Fix that up.

We are sure that we will not have false positives as those memory regions
are reserved and the kernel cannot use them.

Signed-off-by: Ricardo Neri <ricardo.neri-calderon@...ux.intel.com>
---
 arch/x86/mm/fault.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index a241946..f084912 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -14,6 +14,7 @@
 #include <linux/hugetlb.h>		/* hstate_index_to_shift	*/
 #include <linux/prefetch.h>		/* prefetchw			*/
 #include <linux/context_tracking.h>	/* exception_enter(), ...	*/
+#include <linux/efi.h>			/* fixup for buggy UEFI firmware*/
 
 #include <asm/traps.h>			/* dotraplinkage, ...		*/
 #include <asm/pgalloc.h>		/* pgd_*(), ...			*/
@@ -702,6 +703,13 @@ no_context(struct pt_regs *regs, unsigned long error_code,
 		return;
 
 	/*
+	 * Try to fixup faults caused by illegal access to BOOT_SERVICES_*
+	 * regions by UEFI firmware.
+	 */
+	if (efi_boot_services_fixup(address))
+		return;
+
+	/*
 	 * Oops. The kernel tried to access some bad page. We'll have to
 	 * terminate things with extreme prejudice:
 	 */
-- 
1.9.1

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/