97 lines
3.5 KiB
Diff
97 lines
3.5 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: Mon, 4 Dec 2017 15:07:18 +0100
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Subject: [PATCH] x86/dumpstack: Handle stack overflow on all stacks
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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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We currently special-case stack overflow on the task stack. We're
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going to start putting special stacks in the fixmap with a custom
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layout, so they'll have guard pages, too. Teach the unwinder to be
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able to unwind an overflow of any of the stacks.
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Signed-off-by: Andy Lutomirski <luto@kernel.org>
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Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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Reviewed-by: Borislav Petkov <bp@suse.de>
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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: 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: 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: Rik van Riel <riel@redhat.com>
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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/20171204150605.802057305@linutronix.de
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Signed-off-by: Ingo Molnar <mingo@kernel.org>
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(cherry picked from commit 6e60e583426c2f8751c22c2dfe5c207083b4483a)
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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 1ab51120b9a5baaa46979e4ab8ff28916c9cb846)
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Signed-off-by: Fabian Grünbichler <f.gruenbichler@proxmox.com>
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---
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arch/x86/kernel/dumpstack.c | 24 ++++++++++++++----------
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1 file changed, 14 insertions(+), 10 deletions(-)
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diff --git a/arch/x86/kernel/dumpstack.c b/arch/x86/kernel/dumpstack.c
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index c211cbdff709..0f4b931e1a02 100644
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--- a/arch/x86/kernel/dumpstack.c
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+++ b/arch/x86/kernel/dumpstack.c
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@@ -112,24 +112,28 @@ void show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
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* - task stack
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* - interrupt stack
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* - HW exception stacks (double fault, nmi, debug, mce)
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+ * - SYSENTER stack
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*
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- * x86-32 can have up to three stacks:
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+ * x86-32 can have up to four stacks:
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* - task stack
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* - softirq stack
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* - hardirq stack
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+ * - SYSENTER stack
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*/
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for (regs = NULL; stack; stack = PTR_ALIGN(stack_info.next_sp, sizeof(long))) {
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const char *stack_name;
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- /*
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- * If we overflowed the task stack into a guard page, jump back
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- * to the bottom of the usable stack.
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- */
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- if (task_stack_page(task) - (void *)stack < PAGE_SIZE)
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- stack = task_stack_page(task);
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-
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- if (get_stack_info(stack, task, &stack_info, &visit_mask))
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- break;
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+ if (get_stack_info(stack, task, &stack_info, &visit_mask)) {
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+ /*
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+ * We weren't on a valid stack. It's possible that
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+ * we overflowed a valid stack into a guard page.
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+ * See if the next page up is valid so that we can
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+ * generate some kind of backtrace if this happens.
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+ */
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+ stack = (unsigned long *)PAGE_ALIGN((unsigned long)stack);
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+ if (get_stack_info(stack, task, &stack_info, &visit_mask))
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+ break;
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+ }
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stack_name = stack_type_name(stack_info.type);
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if (stack_name)
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--
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2.14.2
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