From: Martin Schwidefsky <schwidefsky-tA70FqPdS9bQT0dZR+AlfA@public.gmane.org>
To: Linus Torvalds
<torvalds-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>
Cc: "Thomas Garnier"
<thgarnie-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>,
"Greg KH" <greg-U8xfFu+wG4EAvxtiuMwx3w@public.gmane.org>,
"Ingo Molnar" <mingo-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
"Kees Cook" <keescook-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>,
"Daniel Micay"
<danielmicay-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
"Heiko Carstens"
<heiko.carstens-tA70FqPdS9bQT0dZR+AlfA@public.gmane.org>,
"Dave Hansen"
<dave.hansen-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>,
"Arnd Bergmann" <arnd-r2nGTMty4D4@public.gmane.org>,
"Thomas Gleixner" <tglx-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org>,
"David Howells"
<dhowells-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>,
"René Nyffenegger"
<mail-gLCNRsNSrVdVZEhyV+6z5nIPMjoJpjVV@public.gmane.org>,
"Andrew Morton"
<akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>,
"Paul E . McKenney"
<paulmck-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>,
"Eric W . Biederman"
<ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>,
"Oleg Nesterov" <oleg-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>,
"Pavel Tikhomirov"
<ptikhomirov-5HdwGun5lf+gSpxsJD1C4w@public.gmane.org>,
"Ingo Molnar" <mingo-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>,
"H . Peter Anvin" <hpa-YMNOUZJC4hwAvxtiuMwx3w@public.gmane.org>,
"Andy Lutomirski" <luto-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
Subject: Re: [kernel-hardening] Re: [PATCH v9 1/4] syscalls: Verify address limit before returning to user-mode
Date: Fri, 12 May 2017 07:28:02 +0200 [thread overview]
Message-ID: <20170512072802.5a686f23@mschwideX1> (raw)
In-Reply-To: <CA+55aFwvQfs_X+paQF6Luc0Rq+W3J2fKuHRou7=ANcquDdXdDA-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
On Thu, 11 May 2017 16:44:07 -0700
Linus Torvalds <torvalds-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org> wrote:
> On Thu, May 11, 2017 at 4:17 PM, Thomas Garnier <thgarnie-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org> wrote:
> >
> > Ingo: Do you want the change as-is? Would you like it to be optional?
> > What do you think?
>
> I'm not ingo, but I don't like that patch. It's in the wrong place -
> that system call return code is too timing-critical to add address
> limit checks.
>
> Now what I think you *could* do is:
>
> - make "set_fs()" actually set a work flag in the current thread flags
>
> - do the test in the slow-path (syscall_return_slowpath).
>
> Yes, yes, that ends up being architecture-specific, but it's fairly simple.
>
> And it only slows down the system calls that actually use "set_fs()".
> Sure, it will slow those down a fair amount, but they are hopefully a
> small subset of all cases.
>
> How does that sound to people? Thats' where we currently do that
>
> if (IS_ENABLED(CONFIG_PROVE_LOCKING) &&
> WARN(irqs_disabled(), "syscall %ld left IRQs disabled",
> regs->orig_ax))
> local_irq_enable();
>
> check too, which is a fairly similar issue.
This is exactly what Heiko did for the s390 backend as a result of this
discussion. See the _CIF_ASCE_SECONDARY bit in arch/s390/kernel/entry.S,
for the hot patch the check for the bit is included in the general
_CIF_WORK test. Only the slow patch gets a bit slower.
git commit b5a882fcf146c87cb6b67c6df353e1c042b8773d
"s390: restore address space when returning to user space".
--
blue skies,
Martin.
"Reality continues to ruin my life." - Calvin.
next prev parent reply other threads:[~2017-05-12 5:28 UTC|newest]
Thread overview: 89+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-28 15:32 [PATCH v9 1/4] syscalls: Verify address limit before returning to user-mode Thomas Garnier
[not found] ` <20170428153213.137279-1-thgarnie-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2017-04-28 15:32 ` [PATCH v9 2/4] x86/syscalls: Optimize address limit check Thomas Garnier
2017-05-05 22:18 ` [PATCH v9 1/4] syscalls: Verify address limit before returning to user-mode Thomas Garnier
[not found] ` <CAJcbSZGQsRVg3QZ9QfLn2HBC+RP-7fUTab0bYDJ455d8y8GyNw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2017-05-08 7:33 ` Ingo Molnar
[not found] ` <20170508073352.caqe3fqf7nuxypgi-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2017-05-08 7:52 ` Ingo Molnar
[not found] ` <20170508075209.7aluvpwildw325rf-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2017-05-08 15:22 ` [kernel-hardening] " Daniel Micay
2017-05-08 15:26 ` Kees Cook
2017-05-08 19:51 ` Thomas Garnier
[not found] ` <CAGXu5jL61K0bRSEg9a_LswNyrt3K1J57REbWVcvAXT54zWwtMA-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2017-05-09 6:56 ` Ingo Molnar
[not found] ` <20170509065619.wmqa6z6w3n6xpvrw-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2017-05-09 11:10 ` Greg KH
[not found] ` <20170509111007.GA14702-U8xfFu+wG4EAvxtiuMwx3w@public.gmane.org>
2017-05-09 14:29 ` Thomas Garnier
[not found] ` <CAJcbSZFswDWZoK-1UK+xkRMJ4ttSYbtH2Y5WD5_aPR-8ru6t8A-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2017-05-11 23:17 ` Thomas Garnier
[not found] ` <CAJcbSZEoRyewUtBHvqmNZL9FtT_q42Vmmd-EuC50x-ZRASiHHg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2017-05-11 23:44 ` Linus Torvalds
[not found] ` <CA+55aFwvQfs_X+paQF6Luc0Rq+W3J2fKuHRou7=ANcquDdXdDA-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2017-05-12 5:28 ` Martin Schwidefsky [this message]
2017-05-12 5:34 ` Kees Cook
2017-05-12 5:54 ` Martin Schwidefsky
2017-05-12 19:01 ` Kees Cook
2017-05-12 19:08 ` Russell King - ARM Linux
[not found] ` <CAGXu5jL9vUrn4kpjO+qa4cHmWBypeqP17OGbrMs=5Nz0YpQMZw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2017-05-12 19:08 ` Linus Torvalds
[not found] ` <CA+55aFzbiBqsYb7vwO=+L4Vp_GOgPu+DBOrq4fBnyzq5DbBehg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2017-05-12 19:30 ` Kees Cook
[not found] ` <CAGXu5j+xmyJ6RhtPw9rUgs7k3sZ1KKWffvyGGG--oPfu9W42ng-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2017-05-12 20:21 ` Russell King - ARM Linux
2017-05-12 20:30 ` Peter Zijlstra
[not found] ` <20170512203044.GI4626-IIpfhp3q70z/8w/KjCw3T+5/BudmfyzbbVWyRVo5IupeoWH0uzbU5w@public.gmane.org>
2017-05-12 20:45 ` Russell King - ARM Linux
2017-05-12 21:00 ` Kees Cook
[not found] ` <CAGXu5jL6FPuShBpZfi6+XHqOk4gxocUJRYPHT5oR3HYh3xm+sA-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2017-05-12 21:04 ` Kees Cook
2017-05-13 7:21 ` Christoph Hellwig
2017-05-12 21:06 ` Al Viro
[not found] ` <20170512210645.GS390-3bDd1+5oDREiFSDQTTA3OLVCufUGDwFn@public.gmane.org>
2017-05-12 21:16 ` [kernel-hardening] " Daniel Micay
2017-05-12 21:17 ` Kees Cook
[not found] ` <CAGXu5jJu=VTqp2tzkPB4RAVxdGC+_SSQwrUwdzWpu24AA-zEcg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2017-05-12 21:23 ` Daniel Micay
2017-05-12 21:41 ` Al Viro
2017-05-12 21:47 ` Rik van Riel
[not found] ` <1494625675.29205.21.camel-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2017-05-12 22:57 ` Al Viro
[not found] ` <20170512214144.GT390-3bDd1+5oDREiFSDQTTA3OLVCufUGDwFn@public.gmane.org>
2017-05-12 21:50 ` Kees Cook
[not found] ` <CAGXu5j+EatK=DYONRkgovwLgytAnbG8jnAZaMSLckZFNVj3gig-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2017-05-12 6:57 ` Ingo Molnar
2017-05-12 6:13 ` Andy Lutomirski
2017-05-12 6:58 ` Ingo Molnar
2017-05-12 17:05 ` Thomas Garnier
2017-05-09 16:30 ` [kernel-hardening] " Kees Cook
2017-05-08 12:46 ` Greg KH
[not found] ` <20170508124621.GA20705-U8xfFu+wG4EAvxtiuMwx3w@public.gmane.org>
2017-05-09 6:45 ` Ingo Molnar
[not found] ` <20170509064522.anusoikaalvlux3w-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2017-05-09 8:56 ` Christoph Hellwig
2017-05-09 13:00 ` Andy Lutomirski
2017-05-09 13:02 ` [kernel-hardening] " Christoph Hellwig
2017-05-09 16:03 ` Christoph Hellwig
2017-05-09 16:50 ` Kees Cook
[not found] ` <CAGXu5jKHVMRMKDfn+=kkbm+JkWPhoEtDwKx=QXAYxg1p9bn7PQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2017-05-09 22:52 ` Andy Lutomirski
[not found] ` <CALCETrV73=cDvaSLOMvb299yaGNJYME8LC-=P+N6p7R1NN97Yg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2017-05-09 23:31 ` Kees Cook
2017-05-10 1:59 ` Andy Lutomirski
2017-05-10 7:15 ` Christoph Hellwig
[not found] ` <CAGXu5jL6PeQmmdxh5h--fgrMK8DW_XZYpNfDOvvv_o9E3-Kxdw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2017-05-11 11:22 ` Borislav Petkov
2017-05-10 6:46 ` Christoph Hellwig
[not found] ` <20170509160322.GA15902-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>
2017-05-10 2:11 ` Al Viro
2017-05-10 2:45 ` Al Viro
2017-05-10 3:12 ` Al Viro
[not found] ` <20170510031254.GC390-3bDd1+5oDREiFSDQTTA3OLVCufUGDwFn@public.gmane.org>
2017-05-10 3:21 ` Al Viro
[not found] ` <20170510032137.GD390-3bDd1+5oDREiFSDQTTA3OLVCufUGDwFn@public.gmane.org>
2017-05-10 3:39 ` Al Viro
2017-05-10 6:54 ` Christoph Hellwig
2017-05-10 6:53 ` Christoph Hellwig
2017-05-10 7:27 ` Al Viro
2017-05-10 7:35 ` Christoph Hellwig
2017-05-10 6:49 ` Christoph Hellwig
2017-05-10 7:28 ` Arnd Bergmann
2017-05-10 7:35 ` Christoph Hellwig
2017-05-09 16:05 ` Brian Gerst
[not found] ` <CALCETrUh8NO2scaqEM48K70Fo2+V3=Cpyk4JurCDiCYp4nm_+g-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2017-05-10 7:37 ` [kernel-hardening] " Arnd Bergmann
2017-05-10 8:08 ` Al Viro
2017-05-10 8:14 ` Christoph Hellwig
2017-05-11 0:18 ` Andy Lutomirski
2017-05-12 7:00 ` Ingo Molnar
2017-05-12 7:15 ` Al Viro
2017-05-12 7:35 ` Christoph Hellwig
2017-05-12 8:07 ` Christoph Hellwig
2017-05-12 8:23 ` Greg KH
[not found] ` <20170512071549.GP390-3bDd1+5oDREiFSDQTTA3OLVCufUGDwFn@public.gmane.org>
2017-05-12 7:43 ` [kernel-hardening] " Arnd Bergmann
2017-05-12 8:11 ` Christoph Hellwig
2017-05-12 8:16 ` Al Viro
2017-05-12 8:11 ` Al Viro
[not found] ` <20170512081154.GQ390-3bDd1+5oDREiFSDQTTA3OLVCufUGDwFn@public.gmane.org>
2017-05-12 8:20 ` Arnd Bergmann
2017-05-12 23:20 ` Andy Lutomirski
2017-05-08 13:09 ` Kees Cook
2017-05-08 14:02 ` Ingo Molnar
[not found] ` <20170508140230.23kxf2kfeazeo4zr-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2017-05-08 14:06 ` Jann Horn
[not found] ` <CAG48ez0Hz=CimkPwuq903tgJkGj8gXUtiQJJb-P2zUes6bd6Hw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2017-05-08 20:48 ` Al Viro
[not found] ` <20170508204858.GT29622-3bDd1+5oDREiFSDQTTA3OLVCufUGDwFn@public.gmane.org>
2017-05-12 23:15 ` Andy Lutomirski
2017-05-08 15:24 ` Kees Cook
[not found] ` <CAGXu5jJ4iY7QZ9wRu5dmm7RHtLh_V6TQh4huWwLCYPKOr63aiA-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2017-05-09 6:34 ` Ingo Molnar
2017-04-28 15:32 ` [PATCH v9 3/4] arm/syscalls: Optimize address limit check Thomas Garnier
2017-04-28 15:32 ` [PATCH v9 4/4] arm64/syscalls: " Thomas Garnier
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