From: Andy Lutomirski <luto@kernel.org>
To: x86@kernel.org, linux-kernel@vger.kernel.org
Cc: linux-arch@vger.kernel.org, Borislav Petkov <bp@alien8.de>,
Nadav Amit <nadav.amit@gmail.com>,
Kees Cook <keescook@chromium.org>,
Brian Gerst <brgerst@gmail.com>,
"kernel-hardening@lists.openwall.com"
<kernel-hardening@lists.openwall.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Josh Poimboeuf <jpoimboe@redhat.com>, Jann Horn <jann@thejh.net>,
Heiko Carstens <heiko.carstens@de.ibm.com>,
Andy Lutomirski <luto@kernel.org>
Subject: [kernel-hardening] [PATCH v2 11/13] x86/dumpstack/64: Handle faults when printing the "Stack:" part of an OOPS
Date: Fri, 17 Jun 2016 13:00:47 -0700 [thread overview]
Message-ID: <bdb80a7119a4045a7c7d78218d14100b027ed1f6.1466192946.git.luto@kernel.org> (raw)
In-Reply-To: <cover.1466192946.git.luto@kernel.org>
In-Reply-To: <cover.1466192946.git.luto@kernel.org>
If we overflow the stack into a guard page, we'll recursively fault
when trying to dump the contents of the guard page. Use
probe_kernel_address so we can recover if this happens.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
---
arch/x86/kernel/dumpstack_64.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kernel/dumpstack_64.c b/arch/x86/kernel/dumpstack_64.c
index 603356a5597a..5e298638c790 100644
--- a/arch/x86/kernel/dumpstack_64.c
+++ b/arch/x86/kernel/dumpstack_64.c
@@ -276,6 +276,8 @@ show_stack_log_lvl(struct task_struct *task, struct pt_regs *regs,
stack = sp;
for (i = 0; i < kstack_depth_to_print; i++) {
+ unsigned long word;
+
if (stack >= irq_stack && stack <= irq_stack_end) {
if (stack == irq_stack_end) {
stack = (unsigned long *) (irq_stack_end[-1]);
@@ -285,12 +287,18 @@ show_stack_log_lvl(struct task_struct *task, struct pt_regs *regs,
if (kstack_end(stack))
break;
}
+
+ if (probe_kernel_address(stack, word))
+ break;
+
if ((i % STACKSLOTS_PER_LINE) == 0) {
if (i != 0)
pr_cont("\n");
- printk("%s %016lx", log_lvl, *stack++);
+ printk("%s %016lx", log_lvl, word);
} else
- pr_cont(" %016lx", *stack++);
+ pr_cont(" %016lx", word);
+
+ stack++;
touch_nmi_watchdog();
}
preempt_enable();
--
2.5.5
next prev parent reply other threads:[~2016-06-17 20:00 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-17 20:00 [kernel-hardening] [PATCH v2 00/13] Virtually mapped stacks with guard pages (x86, core) Andy Lutomirski
2016-06-17 20:00 ` [kernel-hardening] [PATCH v2 01/13] x86/mm/hotplug: Don't remove PGD entries in remove_pagetable() Andy Lutomirski
2016-06-17 20:00 ` [kernel-hardening] [PATCH v2 02/13] x86/cpa: In populate_pgd, don't set the pgd entry until it's populated Andy Lutomirski
2016-06-17 20:00 ` [kernel-hardening] [PATCH v2 03/13] x86/cpa: Warn if kernel_unmap_pages_in_pgd is used inappropriately Andy Lutomirski
2016-06-17 20:30 ` [kernel-hardening] " Borislav Petkov
2016-06-18 10:29 ` Andy Lutomirski
2016-06-18 10:37 ` Borislav Petkov
2016-06-17 20:00 ` [kernel-hardening] [PATCH v2 04/13] mm: Track NR_KERNEL_STACK in KiB instead of number of stacks Andy Lutomirski
2016-06-20 13:16 ` [kernel-hardening] " Michal Hocko
2016-06-17 20:00 ` [kernel-hardening] [PATCH v2 05/13] mm: Move memcg stack accounting to account_kernel_stack Andy Lutomirski
2016-06-17 20:55 ` [kernel-hardening] " Josh Poimboeuf
2016-06-17 22:18 ` Andy Lutomirski
2016-06-20 13:02 ` Michal Hocko
2016-06-20 16:05 ` Andy Lutomirski
2016-06-17 20:00 ` [kernel-hardening] [PATCH v2 06/13] fork: Add generic vmalloced stack support Andy Lutomirski
2016-06-17 20:57 ` [kernel-hardening] " Josh Poimboeuf
2016-06-17 22:18 ` Andy Lutomirski
2016-06-20 13:36 ` Michal Hocko
2016-06-20 16:13 ` Andy Lutomirski
2016-06-21 8:46 ` Michal Hocko
2016-06-21 17:01 ` Andy Lutomirski
2016-06-17 20:00 ` [kernel-hardening] [PATCH v2 07/13] x86/die: Don't try to recover from an OOPS on a non-default stack Andy Lutomirski
2016-06-17 20:00 ` [kernel-hardening] [PATCH v2 08/13] x86/dumpstack: When OOPSing, rewind the stack before do_exit Andy Lutomirski
2016-06-17 20:00 ` [kernel-hardening] [PATCH v2 09/13] x86/dumpstack: When dumping stack bytes due to OOPS, start with regs->sp Andy Lutomirski
2016-06-17 20:00 ` [kernel-hardening] [PATCH v2 10/13] x86/dumpstack: Try harder to get a call trace on stack overflow Andy Lutomirski
2016-06-17 20:00 ` Andy Lutomirski [this message]
2016-06-17 20:00 ` [kernel-hardening] [PATCH v2 12/13] x86/mm/64: Enable vmapped stacks Andy Lutomirski
2016-06-17 20:00 ` [kernel-hardening] [PATCH v2 13/13] x86/mm: Improve stack-overflow #PF handling Andy Lutomirski
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