linux-arm-kernel.lists.infradead.org archive mirror
 help / color / mirror / Atom feed
From: keescook@chromium.org (Kees Cook)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v2 02/11] mm: Hardened usercopy
Date: Thu, 14 Jul 2016 21:25:42 -0700	[thread overview]
Message-ID: <CAGXu5jKzD_rCMNJQU1bB5KDfKTsb+AaidZwe=FAfGMqt_FkfqQ@mail.gmail.com> (raw)
In-Reply-To: <20160714232019.GA28254@350D>

On Thu, Jul 14, 2016 at 4:20 PM, Balbir Singh <bsingharora@gmail.com> wrote:
> On Wed, Jul 13, 2016 at 02:55:55PM -0700, Kees Cook wrote:
>> [...]
>> +++ b/mm/usercopy.c
>> @@ -0,0 +1,219 @@
>> [...]
>> +/*
>> + * Checks if a given pointer and length is contained by the current
>> + * stack frame (if possible).
>> + *
>> + *   0: not at all on the stack
>> + *   1: fully within a valid stack frame
>> + *   2: fully on the stack (when can't do frame-checking)
>> + *   -1: error condition (invalid stack position or bad stack frame)
>
> Can we use enums? Makes it easier to read/debug

Sure, I will update this.

>> [...]
>> +static void report_usercopy(const void *ptr, unsigned long len,
>> +                         bool to_user, const char *type)
>> +{
>> +     pr_emerg("kernel memory %s attempt detected %s %p (%s) (%lu bytes)\n",
>> +             to_user ? "exposure" : "overwrite",
>> +             to_user ? "from" : "to", ptr, type ? : "unknown", len);
>> +     dump_stack();
>> +     do_group_exit(SIGKILL);
>
> SIGKILL -- SIGBUS?

I'd like to keep SIGKILL since it indicates a process fiddling with a
kernel bug. The real problem here is that there doesn't seem to be an
arch-independent way to Oops the kernel and kill a process ("die()" is
closest, but it's defined on a per-arch basis with varying arguments).
This could be a BUG, but I'd rather not panic the entire kernel.

-Kees

-- 
Kees Cook
Chrome OS & Brillo Security

  parent reply	other threads:[~2016-07-15  4:25 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-07-13 21:55 [PATCH v2 0/11] mm: Hardened usercopy Kees Cook
2016-07-13 21:55 ` [PATCH v2 01/11] mm: Implement stack frame object validation Kees Cook
2016-07-13 22:01   ` Andy Lutomirski
2016-07-13 22:04     ` Kees Cook
2016-07-14  5:48       ` Josh Poimboeuf
2016-07-14 18:10         ` Kees Cook
2016-07-14 19:23           ` Josh Poimboeuf
2016-07-14 21:38             ` Kees Cook
2016-07-13 21:55 ` [PATCH v2 02/11] mm: Hardened usercopy Kees Cook
2016-07-14 23:20   ` Balbir Singh
2016-07-15  1:04     ` Rik van Riel
2016-07-15  1:41       ` Balbir Singh
2016-07-15  4:05         ` Kees Cook
2016-07-15  4:53           ` Kees Cook
2016-07-15 12:55             ` Balbir Singh
2016-07-15  4:25     ` Kees Cook [this message]
2016-07-15 19:00       ` [kernel-hardening] " Daniel Micay
2016-07-15 19:14         ` Kees Cook
2016-07-15 19:19           ` Daniel Micay
2016-07-15 19:23             ` Kees Cook
2016-07-13 21:55 ` [PATCH v2 03/11] x86/uaccess: Enable hardened usercopy Kees Cook
2016-07-13 21:55 ` [PATCH v2 04/11] ARM: uaccess: " Kees Cook
2016-07-13 21:55 ` [PATCH v2 05/11] arm64/uaccess: " Kees Cook
2016-07-13 21:55 ` [PATCH v2 06/11] ia64/uaccess: " Kees Cook
2016-07-13 21:56 ` [PATCH v2 07/11] powerpc/uaccess: " Kees Cook
2016-07-13 21:56 ` [PATCH v2 08/11] sparc/uaccess: " Kees Cook
2016-07-13 21:56 ` [PATCH v2 09/11] s390/uaccess: " Kees Cook
2016-07-13 21:56 ` [PATCH v2 10/11] mm: SLAB hardened usercopy support Kees Cook
2016-07-13 21:56 ` [PATCH v2 11/11] mm: SLUB " Kees Cook
2016-07-15  2:05   ` Balbir Singh
2016-07-15  4:29     ` Kees Cook

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='CAGXu5jKzD_rCMNJQU1bB5KDfKTsb+AaidZwe=FAfGMqt_FkfqQ@mail.gmail.com' \
    --to=keescook@chromium.org \
    --cc=linux-arm-kernel@lists.infradead.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).