From: Andy Lutomirski <luto@kernel.org>
To: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Andy Lutomirski <luto@kernel.org>, X86 ML <x86@kernel.org>,
Borislav Petkov <bpetkov@suse.de>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Brian Gerst <brgerst@gmail.com>,
Dave Hansen <dave.hansen@intel.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Josh Poimboeuf <jpoimboe@redhat.com>,
Alexander Potapenko <glider@google.com>,
Dmitry Vyukov <dvyukov@google.com>,
kasan-dev <kasan-dev@googlegroups.com>
Subject: Re: [PATCH v2 06/18] x86/kasan/64: Teach KASAN about the cpu_entry_area
Date: Thu, 23 Nov 2017 07:22:41 -0800 [thread overview]
Message-ID: <CALCETrWK==iEWwBPqdhjSs8tMxH-LbC1KGWQE12UBfuXpi+NYA@mail.gmail.com> (raw)
In-Reply-To: <9e5893bd-097b-005b-342d-8b291aeeda97@virtuozzo.com>
On Thu, Nov 23, 2017 at 2:08 AM, Andrey Ryabinin
<aryabinin@virtuozzo.com> wrote:
>
>
> On 11/22/2017 06:22 PM, Andy Lutomirski wrote:
>> On Wed, Nov 22, 2017 at 1:05 AM, Andrey Ryabinin
>> <aryabinin@virtuozzo.com> wrote:
>>>
>>>
>>> On 11/22/2017 07:44 AM, Andy Lutomirski wrote:
>>>> The cpu_entry_area will contain stacks. Make sure that KASAN has
>>>> appropriate shadow mappings for them.
>>>>
>>>> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
>>>> Cc: Alexander Potapenko <glider@google.com>
>>>> Cc: Dmitry Vyukov <dvyukov@google.com>
>>>> Cc: kasan-dev@googlegroups.com
>>>> Signed-off-by: Andy Lutomirski <luto@kernel.org>
>>>> ---
>>>> arch/x86/mm/kasan_init_64.c | 9 ++++++++-
>>>> 1 file changed, 8 insertions(+), 1 deletion(-)
>>>>
>>>> diff --git a/arch/x86/mm/kasan_init_64.c b/arch/x86/mm/kasan_init_64.c
>>>> index 99dfed6dfef8..43d376687315 100644
>>>> --- a/arch/x86/mm/kasan_init_64.c
>>>> +++ b/arch/x86/mm/kasan_init_64.c
>>>> @@ -330,7 +330,14 @@ void __init kasan_init(void)
>>>> early_pfn_to_nid(__pa(_stext)));
>>>>
>>>> kasan_populate_zero_shadow(kasan_mem_to_shadow((void *)MODULES_END),
>>>> - (void *)KASAN_SHADOW_END);
>>>> + kasan_mem_to_shadow((void *)(__fix_to_virt(FIX_CPU_ENTRY_AREA_BOTTOM))));
>>>> +
>>>> + kasan_populate_shadow((unsigned long)kasan_mem_to_shadow((void *)(__fix_to_virt(FIX_CPU_ENTRY_AREA_BOTTOM))),
>>>> + (unsigned long)kasan_mem_to_shadow((void *)(__fix_to_virt(FIX_CPU_ENTRY_AREA_TOP) + PAGE_SIZE)),
>>>
>>> What's '+ PAGE_SIZE' for?
>>>
>>
>> __fix_to_virt(..._TOP) returns the address of the *bottom* of the last
>> cpu_entry_area page. +PAGE_SIZE returns one past the end of the
>> region, which I assume is the correct thing to pass.
>>
>
> Right.
>
> Perhaps, it would be better to use variables, just avoid such awfully long lines, I mean like this:
> fixmap_shadow_start = (void *)__fix_to_virt(FIX_CPU_ENTRY_AREA_BOTTOM);
> fixmap_shadow_start = kasan_mem_to_shadow(fixmap_shadow_start);
>
> fixmap_shadow_end = (void *)__fix_to_virt(FIX_CPU_ENTRY_AREA_TOP) + PAGE_SIZE;
> fixmap_shadow_end = kasan_mem_to_shadow(fixmap_shadow_end);
>
> kasan_populate_zero_shadow(kasan_mem_to_shadow((void *)MODULES_END),
> fixmap_shadow_start);
>
> kasan_populate_shadow((unsigned long)fixmap_shadow_start,
> (unsigned long)fixmap_shadow_end,
> 0);
>
> I'm also thinking that we should change kasan_populate_shadow() to take void* instead of 'unsigned long'
> to avoid those casts.
I did something similar, but I left the kasan_mem_to_shadow in for
consistency with the rest.
I think the real way to clean this up is like this:
struct kasan_range {
void *start;
void *end;
};
struct kasan_range ranges[] = {
{ range 1 },
{ range 2 },
};
sort(range, ARRAY_SIZE(ranges), sizeof(ranges[0]), ...);
last_end = PAGE_OFFSET; /* or whatever is right */
for (i = 0; i < ARRAY_SIZE(ranges); i++) [
WARN_ON(ranges[i].start < last_end);
if (ranges[i].start > last_end)
kasan_populate_zero_shadow(...);
kasan_populate_shadow(...);
last_end = ranges[i].end;
}
kasan_populate_zero_shadow(last_end, the real end);
Then the code doesn't need to duplicate each boundary or to hardcode
the order in which things appear.
next prev parent reply other threads:[~2017-11-23 15:23 UTC|newest]
Thread overview: 64+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-22 4:43 [PATCH v2 00/18] Entry stack switching Andy Lutomirski
2017-11-22 4:43 ` [PATCH v2 01/18] x86/entry/64: Fix entry_SYSCALL_64_after_hwframe IRQ tracing Andy Lutomirski
2017-11-22 5:35 ` Ingo Molnar
2017-11-22 7:45 ` [tip:x86/urgent] x86/entry/64: Fix entry_SYSCALL_64_after_hwframe() " tip-bot for Andy Lutomirski
2017-11-22 4:43 ` [PATCH v2 02/18] x86/asm/64: Allocate and enable the SYSENTER stack Andy Lutomirski
2017-11-22 4:43 ` [PATCH v2 03/18] x86/dumpstack: Add get_stack_info() support for " Andy Lutomirski
2017-11-22 12:10 ` Borislav Petkov
2017-11-22 4:43 ` [PATCH v2 04/18] x86/gdt: Put per-cpu GDT remaps in ascending order Andy Lutomirski
2017-11-22 11:05 ` Borislav Petkov
2017-11-22 15:26 ` Andy Lutomirski
2017-11-22 4:44 ` [PATCH v2 05/18] x86/fixmap: Generalize the GDT fixmap mechanism Andy Lutomirski
2017-11-22 15:33 ` Borislav Petkov
2017-11-22 17:16 ` Andy Lutomirski
2017-11-22 17:32 ` Borislav Petkov
2017-11-23 15:24 ` Andy Lutomirski
2017-11-23 19:24 ` Thomas Gleixner
2017-11-22 4:44 ` [PATCH v2 06/18] x86/kasan/64: Teach KASAN about the cpu_entry_area Andy Lutomirski
2017-11-22 6:19 ` Ingo Molnar
2017-11-22 9:05 ` Andrey Ryabinin
2017-11-22 15:22 ` Andy Lutomirski
2017-11-23 10:08 ` Andrey Ryabinin
2017-11-23 15:22 ` Andy Lutomirski [this message]
2017-11-22 4:44 ` [PATCH v2 07/18] x86/asm: Fix assumptions that the HW TSS is at the beginning of cpu_tss Andy Lutomirski
2017-11-22 19:06 ` Borislav Petkov
2017-11-22 4:44 ` [PATCH v2 08/18] x86/dumpstack: Handle stack overflow on all stacks Andy Lutomirski
2017-11-23 11:19 ` Borislav Petkov
2017-11-22 4:44 ` [PATCH v2 09/18] x86/asm: Move SYSENTER_stack to the beginning of struct tss_struct Andy Lutomirski
2017-11-23 12:00 ` Borislav Petkov
2017-11-23 13:16 ` Denys Vlasenko
2017-11-23 15:02 ` Andy Lutomirski
2017-11-23 19:30 ` Thomas Gleixner
2017-11-22 4:44 ` [PATCH v2 10/18] x86/asm: Remap the TSS into the cpu entry area Andy Lutomirski
2017-11-23 19:32 ` Thomas Gleixner
2017-11-23 19:55 ` Borislav Petkov
2017-11-23 20:15 ` Andy Lutomirski
2017-11-23 20:37 ` Borislav Petkov
2017-11-24 2:40 ` Andy Lutomirski
2017-11-24 4:17 ` Andy Lutomirski
2017-11-22 4:44 ` [PATCH v2 11/18] x86/asm/64: Separate cpu_current_top_of_stack from TSS.sp0 Andy Lutomirski
2017-11-23 19:34 ` Thomas Gleixner
2017-11-22 4:44 ` [PATCH v2 12/18] x86/espfix/64: Stop assuming that pt_regs is on the entry stack Andy Lutomirski
2017-11-23 19:36 ` Thomas Gleixner
2017-11-22 4:44 ` [PATCH v2 13/18] x86/asm/64: Use a percpu trampoline stack for IDT entries Andy Lutomirski
2017-11-23 23:44 ` Thomas Gleixner
2017-11-24 4:14 ` Andy Lutomirski
2017-11-22 4:44 ` [PATCH v2 14/18] x86/asm/64: Return to userspace from the trampoline stack Andy Lutomirski
2017-11-22 4:44 ` [PATCH v2 15/18] x86/entry/64: Create a percpu SYSCALL entry trampoline Andy Lutomirski
2017-11-22 4:44 ` [PATCH v2 16/18] x86/irq: Remove an old outdated comment about context tracking races Andy Lutomirski
2017-11-22 4:44 ` [PATCH v2 17/18] x86/irq/64: In the stack overflow warning, print the offending IP Andy Lutomirski
2017-11-22 4:44 ` [PATCH v2 18/18] x86/entry/64: Move the IST stacks into cpu_entry_area Andy Lutomirski
2017-11-22 6:22 ` [PATCH v2 00/18] Entry stack switching Ingo Molnar
2017-11-22 6:36 ` Ingo Molnar
2017-11-22 16:23 ` Andy Lutomirski
2017-11-23 6:21 ` Ingo Molnar
2017-11-23 6:44 ` Ingo Molnar
2017-11-23 6:58 ` Ingo Molnar
2017-11-23 15:29 ` Andy Lutomirski
2017-11-23 16:41 ` Thomas Gleixner
2017-11-22 7:39 ` WARNING: can't dereference registers at ffffc90004dfff60 for ip error_entry+0x7d/0xd0 (Re: [PATCH v2 00/18] Entry stack switching) Ingo Molnar
2017-11-22 7:43 ` Ingo Molnar
2017-11-22 13:55 ` Josh Poimboeuf
2017-11-22 15:19 ` Andy Lutomirski
2017-11-22 15:56 ` Ingo Molnar
2017-11-22 16:35 ` Andy Lutomirski
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to='CALCETrWK==iEWwBPqdhjSs8tMxH-LbC1KGWQE12UBfuXpi+NYA@mail.gmail.com' \
--to=luto@kernel.org \
--cc=aryabinin@virtuozzo.com \
--cc=bpetkov@suse.de \
--cc=brgerst@gmail.com \
--cc=dave.hansen@intel.com \
--cc=dvyukov@google.com \
--cc=glider@google.com \
--cc=jpoimboe@redhat.com \
--cc=kasan-dev@googlegroups.com \
--cc=linux-kernel@vger.kernel.org \
--cc=torvalds@linux-foundation.org \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).