104 lines
3.7 KiB
Diff
104 lines
3.7 KiB
Diff
From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
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From: Andy Lutomirski <luto@kernel.org>
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Date: Thu, 2 Nov 2017 00:59:14 -0700
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Subject: [PATCH] x86/entry/64: Remove all remaining direct thread_struct::sp0
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reads
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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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The only remaining readers in context switch code or vm86(), and
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they all just want to update TSS.sp0 to match the current task.
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Replace them all with a new helper update_sp0().
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Signed-off-by: Andy Lutomirski <luto@kernel.org>
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Reviewed-by: Borislav Petkov <bp@suse.de>
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Cc: Borislav Petkov <bpetkov@suse.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: Linus Torvalds <torvalds@linux-foundation.org>
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Cc: Peter Zijlstra <peterz@infradead.org>
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Cc: Thomas Gleixner <tglx@linutronix.de>
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Link: http://lkml.kernel.org/r/2d231687f4ff288c9d9e98d7861b7df374246ac3.1509609304.git.luto@kernel.org
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Signed-off-by: Ingo Molnar <mingo@kernel.org>
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(cherry picked from commit 46f5a10a721ce8dce8cc8fe55279b49e1c6b3288)
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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 cc87284caa7d31d9d5a55c418eb5278cab6e2db1)
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Signed-off-by: Fabian Grünbichler <f.gruenbichler@proxmox.com>
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---
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arch/x86/include/asm/switch_to.h | 6 ++++++
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arch/x86/kernel/process_32.c | 2 +-
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arch/x86/kernel/process_64.c | 2 +-
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arch/x86/kernel/vm86_32.c | 4 ++--
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4 files changed, 10 insertions(+), 4 deletions(-)
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diff --git a/arch/x86/include/asm/switch_to.h b/arch/x86/include/asm/switch_to.h
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index 7ae8caffbada..54e64d909725 100644
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--- a/arch/x86/include/asm/switch_to.h
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+++ b/arch/x86/include/asm/switch_to.h
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@@ -84,4 +84,10 @@ static inline void refresh_sysenter_cs(struct thread_struct *thread)
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}
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#endif
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+/* This is used when switching tasks or entering/exiting vm86 mode. */
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+static inline void update_sp0(struct task_struct *task)
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+{
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+ load_sp0(task->thread.sp0);
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+}
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+
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#endif /* _ASM_X86_SWITCH_TO_H */
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diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c
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index 48a3f240f565..c0d60420466c 100644
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--- a/arch/x86/kernel/process_32.c
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+++ b/arch/x86/kernel/process_32.c
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@@ -287,7 +287,7 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
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* current_thread_info(). Refresh the SYSENTER configuration in
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* case prev or next is vm86.
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*/
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- load_sp0(next->sp0);
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+ update_sp0(next_p);
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refresh_sysenter_cs(next);
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this_cpu_write(cpu_current_top_of_stack,
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(unsigned long)task_stack_page(next_p) +
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diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
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index 37b933628a8b..8a748e17bf6e 100644
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--- a/arch/x86/kernel/process_64.c
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+++ b/arch/x86/kernel/process_64.c
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@@ -466,7 +466,7 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
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this_cpu_write(current_task, next_p);
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/* Reload sp0. */
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- load_sp0(next->sp0);
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+ update_sp0(next_p);
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/*
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* Now maybe reload the debug registers and handle I/O bitmaps
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diff --git a/arch/x86/kernel/vm86_32.c b/arch/x86/kernel/vm86_32.c
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index 0f1d92cd20ad..a7b44c75c642 100644
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--- a/arch/x86/kernel/vm86_32.c
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+++ b/arch/x86/kernel/vm86_32.c
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@@ -148,7 +148,7 @@ void save_v86_state(struct kernel_vm86_regs *regs, int retval)
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preempt_disable();
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tsk->thread.sp0 = vm86->saved_sp0;
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tsk->thread.sysenter_cs = __KERNEL_CS;
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- load_sp0(tsk->thread.sp0);
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+ update_sp0(tsk);
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refresh_sysenter_cs(&tsk->thread);
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vm86->saved_sp0 = 0;
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preempt_enable();
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@@ -373,7 +373,7 @@ static long do_sys_vm86(struct vm86plus_struct __user *user_vm86, bool plus)
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refresh_sysenter_cs(&tsk->thread);
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}
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- load_sp0(tsk->thread.sp0);
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+ update_sp0(tsk);
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preempt_enable();
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if (vm86->flags & VM86_SCREEN_BITMAP)
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--
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2.14.2
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