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59d5af67 | 1 | From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001 |
321d628a FG |
2 | From: Andy Lutomirski <luto@kernel.org> |
3 | Date: Thu, 2 Nov 2017 00:59:14 -0700 | |
59d5af67 FG |
4 | Subject: [PATCH] x86/entry/64: Remove all remaining direct thread_struct::sp0 |
5 | reads | |
321d628a FG |
6 | MIME-Version: 1.0 |
7 | Content-Type: text/plain; charset=UTF-8 | |
8 | Content-Transfer-Encoding: 8bit | |
9 | ||
10 | CVE-2017-5754 | |
11 | ||
12 | The only remaining readers in context switch code or vm86(), and | |
13 | they all just want to update TSS.sp0 to match the current task. | |
14 | Replace them all with a new helper update_sp0(). | |
15 | ||
16 | Signed-off-by: Andy Lutomirski <luto@kernel.org> | |
17 | Reviewed-by: Borislav Petkov <bp@suse.de> | |
18 | Cc: Borislav Petkov <bpetkov@suse.de> | |
19 | Cc: Brian Gerst <brgerst@gmail.com> | |
20 | Cc: Dave Hansen <dave.hansen@intel.com> | |
21 | Cc: Linus Torvalds <torvalds@linux-foundation.org> | |
22 | Cc: Peter Zijlstra <peterz@infradead.org> | |
23 | Cc: Thomas Gleixner <tglx@linutronix.de> | |
24 | Link: http://lkml.kernel.org/r/2d231687f4ff288c9d9e98d7861b7df374246ac3.1509609304.git.luto@kernel.org | |
25 | Signed-off-by: Ingo Molnar <mingo@kernel.org> | |
26 | (cherry picked from commit 46f5a10a721ce8dce8cc8fe55279b49e1c6b3288) | |
27 | Signed-off-by: Andy Whitcroft <apw@canonical.com> | |
28 | Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com> | |
29 | (cherry picked from commit cc87284caa7d31d9d5a55c418eb5278cab6e2db1) | |
30 | Signed-off-by: Fabian Grünbichler <f.gruenbichler@proxmox.com> | |
31 | --- | |
32 | arch/x86/include/asm/switch_to.h | 6 ++++++ | |
33 | arch/x86/kernel/process_32.c | 2 +- | |
34 | arch/x86/kernel/process_64.c | 2 +- | |
35 | arch/x86/kernel/vm86_32.c | 4 ++-- | |
36 | 4 files changed, 10 insertions(+), 4 deletions(-) | |
37 | ||
38 | diff --git a/arch/x86/include/asm/switch_to.h b/arch/x86/include/asm/switch_to.h | |
39 | index 7ae8caffbada..54e64d909725 100644 | |
40 | --- a/arch/x86/include/asm/switch_to.h | |
41 | +++ b/arch/x86/include/asm/switch_to.h | |
42 | @@ -84,4 +84,10 @@ static inline void refresh_sysenter_cs(struct thread_struct *thread) | |
43 | } | |
44 | #endif | |
45 | ||
46 | +/* This is used when switching tasks or entering/exiting vm86 mode. */ | |
47 | +static inline void update_sp0(struct task_struct *task) | |
48 | +{ | |
49 | + load_sp0(task->thread.sp0); | |
50 | +} | |
51 | + | |
52 | #endif /* _ASM_X86_SWITCH_TO_H */ | |
53 | diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c | |
54 | index 48a3f240f565..c0d60420466c 100644 | |
55 | --- a/arch/x86/kernel/process_32.c | |
56 | +++ b/arch/x86/kernel/process_32.c | |
57 | @@ -287,7 +287,7 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p) | |
58 | * current_thread_info(). Refresh the SYSENTER configuration in | |
59 | * case prev or next is vm86. | |
60 | */ | |
61 | - load_sp0(next->sp0); | |
62 | + update_sp0(next_p); | |
63 | refresh_sysenter_cs(next); | |
64 | this_cpu_write(cpu_current_top_of_stack, | |
65 | (unsigned long)task_stack_page(next_p) + | |
66 | diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c | |
67 | index 37b933628a8b..8a748e17bf6e 100644 | |
68 | --- a/arch/x86/kernel/process_64.c | |
69 | +++ b/arch/x86/kernel/process_64.c | |
70 | @@ -466,7 +466,7 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p) | |
71 | this_cpu_write(current_task, next_p); | |
72 | ||
73 | /* Reload sp0. */ | |
74 | - load_sp0(next->sp0); | |
75 | + update_sp0(next_p); | |
76 | ||
77 | /* | |
78 | * Now maybe reload the debug registers and handle I/O bitmaps | |
79 | diff --git a/arch/x86/kernel/vm86_32.c b/arch/x86/kernel/vm86_32.c | |
80 | index 0f1d92cd20ad..a7b44c75c642 100644 | |
81 | --- a/arch/x86/kernel/vm86_32.c | |
82 | +++ b/arch/x86/kernel/vm86_32.c | |
83 | @@ -148,7 +148,7 @@ void save_v86_state(struct kernel_vm86_regs *regs, int retval) | |
84 | preempt_disable(); | |
85 | tsk->thread.sp0 = vm86->saved_sp0; | |
86 | tsk->thread.sysenter_cs = __KERNEL_CS; | |
87 | - load_sp0(tsk->thread.sp0); | |
88 | + update_sp0(tsk); | |
89 | refresh_sysenter_cs(&tsk->thread); | |
90 | vm86->saved_sp0 = 0; | |
91 | preempt_enable(); | |
92 | @@ -373,7 +373,7 @@ static long do_sys_vm86(struct vm86plus_struct __user *user_vm86, bool plus) | |
93 | refresh_sysenter_cs(&tsk->thread); | |
94 | } | |
95 | ||
96 | - load_sp0(tsk->thread.sp0); | |
97 | + update_sp0(tsk); | |
98 | preempt_enable(); | |
99 | ||
100 | if (vm86->flags & VM86_SCREEN_BITMAP) | |
101 | -- | |
102 | 2.14.2 | |
103 |