122 lines
3.8 KiB
Diff
122 lines
3.8 KiB
Diff
From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
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From: Borislav Petkov <bp@suse.de>
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Date: Tue, 12 Dec 2017 14:39:52 +0100
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Subject: [PATCH] x86/pti: Add the pti= cmdline option and documentation
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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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Keep the "nopti" optional for traditional reasons.
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[ tglx: Don't allow force on when running on XEN PV and made 'on'
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printout conditional ]
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Requested-by: Linus Torvalds <torvalds@linux-foundation.org>
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Signed-off-by: Borislav Petkov <bp@suse.de>
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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: Andy Lutomirsky <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@intel.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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Link: https://lkml.kernel.org/r/20171212133952.10177-1-bp@alien8.de
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Signed-off-by: Ingo Molnar <mingo@kernel.org>
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(cherry picked from commit 41f4c20b57a4890ea7f56ff8717cc83fefb8d537)
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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 96d3670fa8f88989fb7c0be5172a1378143f3296)
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Signed-off-by: Fabian Grünbichler <f.gruenbichler@proxmox.com>
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---
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Documentation/admin-guide/kernel-parameters.txt | 6 ++++++
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arch/x86/mm/pti.c | 26 ++++++++++++++++++++++++-
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2 files changed, 31 insertions(+), 1 deletion(-)
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diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
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index e2a4608da5d2..b4d2edf316db 100644
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--- a/Documentation/admin-guide/kernel-parameters.txt
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+++ b/Documentation/admin-guide/kernel-parameters.txt
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@@ -3247,6 +3247,12 @@
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pt. [PARIDE]
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See Documentation/blockdev/paride.txt.
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+ pti= [X86_64]
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+ Control user/kernel address space isolation:
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+ on - enable
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+ off - disable
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+ auto - default setting
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+
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pty.legacy_count=
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[KNL] Number of legacy pty's. Overwrites compiled-in
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default number.
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diff --git a/arch/x86/mm/pti.c b/arch/x86/mm/pti.c
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index 375f23a758bc..a13f6b109865 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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@@ -54,21 +54,45 @@ static void __init pti_print_if_insecure(const char *reason)
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pr_info("%s\n", reason);
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}
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+static void __init pti_print_if_secure(const char *reason)
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+{
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+ if (!boot_cpu_has_bug(X86_BUG_CPU_INSECURE))
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+ pr_info("%s\n", reason);
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+}
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+
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void __init pti_check_boottime_disable(void)
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{
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+ char arg[5];
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+ int ret;
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+
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if (hypervisor_is_type(X86_HYPER_XEN_PV)) {
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pti_print_if_insecure("disabled on XEN PV.");
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return;
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}
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+ ret = cmdline_find_option(boot_command_line, "pti", arg, sizeof(arg));
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+ if (ret > 0) {
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+ if (ret == 3 && !strncmp(arg, "off", 3)) {
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+ pti_print_if_insecure("disabled on command line.");
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+ return;
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+ }
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+ if (ret == 2 && !strncmp(arg, "on", 2)) {
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+ pti_print_if_secure("force enabled on command line.");
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+ goto enable;
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+ }
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+ if (ret == 4 && !strncmp(arg, "auto", 4))
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+ goto autosel;
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+ }
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+
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if (cmdline_find_option_bool(boot_command_line, "nopti")) {
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pti_print_if_insecure("disabled on command line.");
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return;
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}
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+autosel:
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if (!boot_cpu_has_bug(X86_BUG_CPU_INSECURE))
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return;
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-
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+enable:
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setup_force_cpu_cap(X86_FEATURE_PTI);
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}
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--
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2.14.2
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