633c5ed17f
this causes kernel OOPS and upstream is unresponsive about it. see https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1726519
85 lines
2.9 KiB
Diff
85 lines
2.9 KiB
Diff
From ea96d1e71945047c9e0af526e68b18782acc12c4 Mon Sep 17 00:00:00 2001
|
|
From: Dave Hansen <dave.hansen@linux.intel.com>
|
|
Date: Mon, 4 Dec 2017 15:07:38 +0100
|
|
Subject: [PATCH 193/242] x86/mm/pti: Allow NX poison to be set in p4d/pgd
|
|
MIME-Version: 1.0
|
|
Content-Type: text/plain; charset=UTF-8
|
|
Content-Transfer-Encoding: 8bit
|
|
|
|
CVE-2017-5754
|
|
|
|
With PAGE_TABLE_ISOLATION the user portion of the kernel page tables is
|
|
poisoned with the NX bit so if the entry code exits with the kernel page
|
|
tables selected in CR3, userspace crashes.
|
|
|
|
But doing so trips the p4d/pgd_bad() checks. Make sure it does not do
|
|
that.
|
|
|
|
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
|
|
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
|
|
Reviewed-by: Borislav Petkov <bp@suse.de>
|
|
Cc: Andy Lutomirski <luto@kernel.org>
|
|
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
|
|
Cc: Borislav Petkov <bp@alien8.de>
|
|
Cc: Brian Gerst <brgerst@gmail.com>
|
|
Cc: David Laight <David.Laight@aculab.com>
|
|
Cc: Denys Vlasenko <dvlasenk@redhat.com>
|
|
Cc: Eduardo Valentin <eduval@amazon.com>
|
|
Cc: Greg KH <gregkh@linuxfoundation.org>
|
|
Cc: H. Peter Anvin <hpa@zytor.com>
|
|
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
|
|
Cc: Juergen Gross <jgross@suse.com>
|
|
Cc: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Cc: Peter Zijlstra <peterz@infradead.org>
|
|
Cc: Will Deacon <will.deacon@arm.com>
|
|
Cc: aliguori@amazon.com
|
|
Cc: daniel.gruss@iaik.tugraz.at
|
|
Cc: hughd@google.com
|
|
Cc: keescook@google.com
|
|
Cc: linux-kernel@vger.kernel.org
|
|
Signed-off-by: Ingo Molnar <mingo@kernel.org>
|
|
(cherry picked from commit 1c4de1ff4fe50453b968579ee86fac3da80dd783)
|
|
Signed-off-by: Andy Whitcroft <apw@canonical.com>
|
|
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>
|
|
(cherry picked from commit 889a8bd0e57e39e7ce337e87c55fa59c09644d4e)
|
|
Signed-off-by: Fabian Grünbichler <f.gruenbichler@proxmox.com>
|
|
---
|
|
arch/x86/include/asm/pgtable.h | 14 ++++++++++++--
|
|
1 file changed, 12 insertions(+), 2 deletions(-)
|
|
|
|
diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
|
|
index abbb47c75467..3ef8415b2358 100644
|
|
--- a/arch/x86/include/asm/pgtable.h
|
|
+++ b/arch/x86/include/asm/pgtable.h
|
|
@@ -831,7 +831,12 @@ static inline pud_t *pud_offset(p4d_t *p4d, unsigned long address)
|
|
|
|
static inline int p4d_bad(p4d_t p4d)
|
|
{
|
|
- return (p4d_flags(p4d) & ~(_KERNPG_TABLE | _PAGE_USER)) != 0;
|
|
+ unsigned long ignore_flags = _KERNPG_TABLE | _PAGE_USER;
|
|
+
|
|
+ if (IS_ENABLED(CONFIG_PAGE_TABLE_ISOLATION))
|
|
+ ignore_flags |= _PAGE_NX;
|
|
+
|
|
+ return (p4d_flags(p4d) & ~ignore_flags) != 0;
|
|
}
|
|
#endif /* CONFIG_PGTABLE_LEVELS > 3 */
|
|
|
|
@@ -865,7 +870,12 @@ static inline p4d_t *p4d_offset(pgd_t *pgd, unsigned long address)
|
|
|
|
static inline int pgd_bad(pgd_t pgd)
|
|
{
|
|
- return (pgd_flags(pgd) & ~_PAGE_USER) != _KERNPG_TABLE;
|
|
+ unsigned long ignore_flags = _PAGE_USER;
|
|
+
|
|
+ if (IS_ENABLED(CONFIG_PAGE_TABLE_ISOLATION))
|
|
+ ignore_flags |= _PAGE_NX;
|
|
+
|
|
+ return (pgd_flags(pgd) & ~ignore_flags) != _KERNPG_TABLE;
|
|
}
|
|
|
|
static inline int pgd_none(pgd_t pgd)
|
|
--
|
|
2.14.2
|
|
|