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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: Mon, 4 Dec 2017 15:07:18 +0100 | |
59d5af67 | 4 | Subject: [PATCH] x86/dumpstack: Handle stack overflow on all stacks |
321d628a FG |
5 | MIME-Version: 1.0 |
6 | Content-Type: text/plain; charset=UTF-8 | |
7 | Content-Transfer-Encoding: 8bit | |
8 | ||
9 | CVE-2017-5754 | |
10 | ||
11 | We currently special-case stack overflow on the task stack. We're | |
12 | going to start putting special stacks in the fixmap with a custom | |
13 | layout, so they'll have guard pages, too. Teach the unwinder to be | |
14 | able to unwind an overflow of any of the stacks. | |
15 | ||
16 | Signed-off-by: Andy Lutomirski <luto@kernel.org> | |
17 | Signed-off-by: Thomas Gleixner <tglx@linutronix.de> | |
18 | Reviewed-by: Borislav Petkov <bp@suse.de> | |
19 | Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> | |
20 | Cc: Borislav Petkov <bp@alien8.de> | |
21 | Cc: Borislav Petkov <bpetkov@suse.de> | |
22 | Cc: Brian Gerst <brgerst@gmail.com> | |
23 | Cc: Dave Hansen <dave.hansen@intel.com> | |
24 | Cc: Dave Hansen <dave.hansen@linux.intel.com> | |
25 | Cc: David Laight <David.Laight@aculab.com> | |
26 | Cc: Denys Vlasenko <dvlasenk@redhat.com> | |
27 | Cc: Eduardo Valentin <eduval@amazon.com> | |
28 | Cc: Greg KH <gregkh@linuxfoundation.org> | |
29 | Cc: H. Peter Anvin <hpa@zytor.com> | |
30 | Cc: Josh Poimboeuf <jpoimboe@redhat.com> | |
31 | Cc: Juergen Gross <jgross@suse.com> | |
32 | Cc: Linus Torvalds <torvalds@linux-foundation.org> | |
33 | Cc: Peter Zijlstra <peterz@infradead.org> | |
34 | Cc: Rik van Riel <riel@redhat.com> | |
35 | Cc: Will Deacon <will.deacon@arm.com> | |
36 | Cc: aliguori@amazon.com | |
37 | Cc: daniel.gruss@iaik.tugraz.at | |
38 | Cc: hughd@google.com | |
39 | Cc: keescook@google.com | |
40 | Link: https://lkml.kernel.org/r/20171204150605.802057305@linutronix.de | |
41 | Signed-off-by: Ingo Molnar <mingo@kernel.org> | |
42 | (cherry picked from commit 6e60e583426c2f8751c22c2dfe5c207083b4483a) | |
43 | Signed-off-by: Andy Whitcroft <apw@canonical.com> | |
44 | Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com> | |
45 | (cherry picked from commit 1ab51120b9a5baaa46979e4ab8ff28916c9cb846) | |
46 | Signed-off-by: Fabian Grünbichler <f.gruenbichler@proxmox.com> | |
47 | --- | |
48 | arch/x86/kernel/dumpstack.c | 24 ++++++++++++++---------- | |
49 | 1 file changed, 14 insertions(+), 10 deletions(-) | |
50 | ||
51 | diff --git a/arch/x86/kernel/dumpstack.c b/arch/x86/kernel/dumpstack.c | |
52 | index c211cbdff709..0f4b931e1a02 100644 | |
53 | --- a/arch/x86/kernel/dumpstack.c | |
54 | +++ b/arch/x86/kernel/dumpstack.c | |
55 | @@ -112,24 +112,28 @@ void show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs, | |
56 | * - task stack | |
57 | * - interrupt stack | |
58 | * - HW exception stacks (double fault, nmi, debug, mce) | |
59 | + * - SYSENTER stack | |
60 | * | |
61 | - * x86-32 can have up to three stacks: | |
62 | + * x86-32 can have up to four stacks: | |
63 | * - task stack | |
64 | * - softirq stack | |
65 | * - hardirq stack | |
66 | + * - SYSENTER stack | |
67 | */ | |
68 | for (regs = NULL; stack; stack = PTR_ALIGN(stack_info.next_sp, sizeof(long))) { | |
69 | const char *stack_name; | |
70 | ||
71 | - /* | |
72 | - * If we overflowed the task stack into a guard page, jump back | |
73 | - * to the bottom of the usable stack. | |
74 | - */ | |
75 | - if (task_stack_page(task) - (void *)stack < PAGE_SIZE) | |
76 | - stack = task_stack_page(task); | |
77 | - | |
78 | - if (get_stack_info(stack, task, &stack_info, &visit_mask)) | |
79 | - break; | |
80 | + if (get_stack_info(stack, task, &stack_info, &visit_mask)) { | |
81 | + /* | |
82 | + * We weren't on a valid stack. It's possible that | |
83 | + * we overflowed a valid stack into a guard page. | |
84 | + * See if the next page up is valid so that we can | |
85 | + * generate some kind of backtrace if this happens. | |
86 | + */ | |
87 | + stack = (unsigned long *)PAGE_ALIGN((unsigned long)stack); | |
88 | + if (get_stack_info(stack, task, &stack_info, &visit_mask)) | |
89 | + break; | |
90 | + } | |
91 | ||
92 | stack_name = stack_type_name(stack_info.type); | |
93 | if (stack_name) | |
94 | -- | |
95 | 2.14.2 | |
96 |