75 lines
2.4 KiB
Diff
75 lines
2.4 KiB
Diff
From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
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From: Thomas Gleixner <tglx@linutronix.de>
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Date: Mon, 4 Dec 2017 15:07:47 +0100
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Subject: [PATCH] x86/mm/pti: Share entry text PMD
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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CVE-2017-5754
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Share the entry text PMD of the kernel mapping with the user space
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mapping. If large pages are enabled this is a single PMD entry and at the
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point where it is copied into the user page table the RW bit has not been
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cleared yet. Clear it right away so the user space visible map becomes RX.
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Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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Cc: Andy Lutomirski <luto@kernel.org>
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Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
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Cc: Borislav Petkov <bp@alien8.de>
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Cc: Brian Gerst <brgerst@gmail.com>
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Cc: Dave Hansen <dave.hansen@linux.intel.com>
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Cc: David Laight <David.Laight@aculab.com>
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Cc: Denys Vlasenko <dvlasenk@redhat.com>
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Cc: Eduardo Valentin <eduval@amazon.com>
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Cc: Greg KH <gregkh@linuxfoundation.org>
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Cc: H. Peter Anvin <hpa@zytor.com>
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Cc: Josh Poimboeuf <jpoimboe@redhat.com>
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Cc: Juergen Gross <jgross@suse.com>
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Cc: Linus Torvalds <torvalds@linux-foundation.org>
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Cc: Peter Zijlstra <peterz@infradead.org>
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Cc: Will Deacon <will.deacon@arm.com>
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Cc: aliguori@amazon.com
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Cc: daniel.gruss@iaik.tugraz.at
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Cc: hughd@google.com
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Cc: keescook@google.com
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Signed-off-by: Ingo Molnar <mingo@kernel.org>
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(cherry picked from commit 6dc72c3cbca0580642808d677181cad4c6433893)
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Signed-off-by: Andy Whitcroft <apw@canonical.com>
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Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>
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(cherry picked from commit ee98d7446b4a7c12a57a38b1a5f51e3df0ac2cf3)
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Signed-off-by: Fabian Grünbichler <f.gruenbichler@proxmox.com>
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---
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arch/x86/mm/pti.c | 10 ++++++++++
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1 file changed, 10 insertions(+)
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diff --git a/arch/x86/mm/pti.c b/arch/x86/mm/pti.c
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index 59290356f19f..0e78797650a7 100644
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--- a/arch/x86/mm/pti.c
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+++ b/arch/x86/mm/pti.c
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@@ -287,6 +287,15 @@ static void __init pti_clone_user_shared(void)
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pti_clone_p4d(CPU_ENTRY_AREA_BASE);
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}
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+/*
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+ * Clone the populated PMDs of the entry and irqentry text and force it RO.
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+ */
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+static void __init pti_clone_entry_text(void)
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+{
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+ pti_clone_pmds((unsigned long) __entry_text_start,
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+ (unsigned long) __irqentry_text_end, _PAGE_RW);
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+}
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+
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/*
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* Initialize kernel page table isolation
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*/
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@@ -298,4 +307,5 @@ void __init pti_init(void)
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pr_info("enabled\n");
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pti_clone_user_shared();
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+ pti_clone_entry_text();
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}
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--
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2.14.2
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