From: Peter Zijlstra <peterz@infradead.org> To: Kees Cook <keescook@chromium.org> Cc: "Reshetova, Elena" <elena.reshetova@intel.com>, Greg KH <gregkh@linuxfoundation.org>, Arnd Bergmann <arnd@arndb.de>, Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@kernel.org>, "H. Peter Anvin" <h.peter.anvin@intel.com>, Will Deacon <will.deacon@arm.com>, David Windsor <dwindsor@gmail.com>, Hans Liljestrand <ishkamiel@gmail.com>, David Howells <dhowells@redhat.com>, LKML <linux-kernel@vger.kernel.org>, "kernel-hardening@lists.openwall.com" <kernel-hardening@lists.openwall.com> Subject: Re: [PATCH 4/4] refcount: Report failures through CHECK_DATA_CORRUPTION Date: Tue, 7 Feb 2017 09:34:05 +0100 [thread overview] Message-ID: <20170207083405.GV6500@twins.programming.kicks-ass.net> (raw) In-Reply-To: <CAGXu5j+VrKBrU7op8wD1Ry4nzR0cN7Vvke8W6_KOzp3wsoEF1g@mail.gmail.com> On Mon, Feb 06, 2017 at 08:54:38AM -0800, Kees Cook wrote: > > > > Like I wrote, ideally we'd end up using something like the x86 exception > > table with a custom handler. Just no idea how to pull that off without > > doing a full blown arch specific implementation, so I didn't go there > > quite yet. > > I haven't spent much time looking at the extable stuff. (Though > coincidentally, I was poking at it for x86's test_nx stuff...) I > thought there was a way to build arch-agnostic extables already? > kernel/extable.c is unconditionally built-in, for example. That doesn't seem to be of much use. It only contains section sort and search functions. Another problem for generic code would be to figure out what register the relevant variable would live in at the time of exception. Here its 'obviously' EAX because that's what cmpxchg requires, but in generic you'd need a means of querying GCC's register allocator at the exception point and somehow using that information for the generation of the exception handler. AFAIK that's not something GCC can do. > > and the handler is shared between all instances and can be as big and > > fancy as we'd like. > > I'll dig a bit to see what I can build. Can you add the lkdtm tests to > the series, though? That should be fine as-is. Yes, I did. I also did the 's/--help--/help/' and 's/#if/#ifdef/' thing. Thanks!
WARNING: multiple messages have this Message-ID (diff)
From: Peter Zijlstra <peterz@infradead.org> To: Kees Cook <keescook@chromium.org> Cc: "Reshetova, Elena" <elena.reshetova@intel.com>, Greg KH <gregkh@linuxfoundation.org>, Arnd Bergmann <arnd@arndb.de>, Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@kernel.org>, "H. Peter Anvin" <h.peter.anvin@intel.com>, Will Deacon <will.deacon@arm.com>, David Windsor <dwindsor@gmail.com>, Hans Liljestrand <ishkamiel@gmail.com>, David Howells <dhowells@redhat.com>, LKML <linux-kernel@vger.kernel.org>, "kernel-hardening@lists.openwall.com" <kernel-hardening@lists.openwall.com> Subject: [kernel-hardening] Re: [PATCH 4/4] refcount: Report failures through CHECK_DATA_CORRUPTION Date: Tue, 7 Feb 2017 09:34:05 +0100 [thread overview] Message-ID: <20170207083405.GV6500@twins.programming.kicks-ass.net> (raw) In-Reply-To: <CAGXu5j+VrKBrU7op8wD1Ry4nzR0cN7Vvke8W6_KOzp3wsoEF1g@mail.gmail.com> On Mon, Feb 06, 2017 at 08:54:38AM -0800, Kees Cook wrote: > > > > Like I wrote, ideally we'd end up using something like the x86 exception > > table with a custom handler. Just no idea how to pull that off without > > doing a full blown arch specific implementation, so I didn't go there > > quite yet. > > I haven't spent much time looking at the extable stuff. (Though > coincidentally, I was poking at it for x86's test_nx stuff...) I > thought there was a way to build arch-agnostic extables already? > kernel/extable.c is unconditionally built-in, for example. That doesn't seem to be of much use. It only contains section sort and search functions. Another problem for generic code would be to figure out what register the relevant variable would live in at the time of exception. Here its 'obviously' EAX because that's what cmpxchg requires, but in generic you'd need a means of querying GCC's register allocator at the exception point and somehow using that information for the generation of the exception handler. AFAIK that's not something GCC can do. > > and the handler is shared between all instances and can be as big and > > fancy as we'd like. > > I'll dig a bit to see what I can build. Can you add the lkdtm tests to > the series, though? That should be fine as-is. Yes, I did. I also did the 's/--help--/help/' and 's/#if/#ifdef/' thing. Thanks!
next prev parent reply other threads:[~2017-02-07 8:34 UTC|newest] Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top 2017-02-03 23:26 [PATCH 0/4] refcount_t followups Kees Cook 2017-02-03 23:26 ` [kernel-hardening] " Kees Cook 2017-02-03 23:26 ` [PATCH 1/4] refcount_t: fix Kconfig help Kees Cook 2017-02-03 23:26 ` [kernel-hardening] " Kees Cook 2017-02-03 23:26 ` [PATCH 2/4] lkdtm: convert to refcount_t testing Kees Cook 2017-02-03 23:26 ` [kernel-hardening] " Kees Cook 2017-02-10 8:32 ` [tip:locking/core] lkdtm: Convert " tip-bot for Kees Cook 2017-02-03 23:26 ` [PATCH 3/4] bug: Switch data corruption check to __must_check Kees Cook 2017-02-03 23:26 ` [kernel-hardening] " Kees Cook 2017-02-03 23:26 ` [PATCH 4/4] refcount: Report failures through CHECK_DATA_CORRUPTION Kees Cook 2017-02-03 23:26 ` [kernel-hardening] " Kees Cook 2017-02-05 15:40 ` Peter Zijlstra 2017-02-05 15:40 ` [kernel-hardening] " Peter Zijlstra 2017-02-05 23:33 ` Kees Cook 2017-02-05 23:33 ` [kernel-hardening] " Kees Cook 2017-02-06 8:57 ` Peter Zijlstra 2017-02-06 8:57 ` [kernel-hardening] " Peter Zijlstra 2017-02-06 16:54 ` Kees Cook 2017-02-06 16:54 ` [kernel-hardening] " Kees Cook 2017-02-07 8:34 ` Peter Zijlstra [this message] 2017-02-07 8:34 ` Peter Zijlstra 2017-02-07 11:10 ` Mark Rutland 2017-02-07 11:10 ` Mark Rutland 2017-02-07 12:36 ` Peter Zijlstra 2017-02-07 12:36 ` Peter Zijlstra 2017-02-07 13:50 ` Mark Rutland 2017-02-07 13:50 ` Mark Rutland 2017-02-07 15:07 ` Peter Zijlstra 2017-02-07 15:07 ` Peter Zijlstra 2017-02-07 16:03 ` Mark Rutland 2017-02-07 16:03 ` Mark Rutland 2017-02-07 17:30 ` Peter Zijlstra 2017-02-07 17:30 ` Peter Zijlstra 2017-02-07 17:55 ` Mark Rutland 2017-02-07 17:55 ` Mark Rutland 2017-02-08 9:12 ` Peter Zijlstra 2017-02-08 9:12 ` Peter Zijlstra 2017-02-08 9:43 ` Peter Zijlstra 2017-02-08 9:43 ` Peter Zijlstra 2017-02-08 14:10 ` Mark Rutland 2017-02-08 14:10 ` Mark Rutland 2017-02-08 21:20 ` Kees Cook 2017-02-08 21:20 ` Kees Cook 2017-02-09 10:27 ` Peter Zijlstra 2017-02-09 10:27 ` Peter Zijlstra 2017-02-10 23:39 ` Kees Cook 2017-02-10 23:39 ` Kees Cook
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