From: Andrew Morton <akpm@linux-foundation.org>
To: Will Drewry <wad@chromium.org>
Cc: Indan Zupancic <indan@nul.nu>,
linux-kernel@vger.kernel.org,
linux-security-module@vger.kernel.org,
linux-arch@vger.kernel.org, linux-doc@vger.kernel.org,
kernel-hardening@lists.openwall.com, netdev@vger.kernel.org,
x86@kernel.org, arnd@arndb.de, davem@davemloft.net,
hpa@zytor.com, mingo@redhat.com, oleg@redhat.com,
peterz@infradead.org, rdunlap@xenotime.net,
mcgrathr@chromium.org, tglx@linutronix.de, luto@mit.edu,
eparis@redhat.com, serge.hallyn@canonical.com, djm@mindrot.org,
scarybeasts@gmail.com, pmoore@redhat.com, corbet@lwn.net,
eric.dumazet@gmail.com, markus@chromium.org,
coreyb@linux.vnet.ibm.com, keescook@chromium.org,
jmorris@namei.org
Subject: [kernel-hardening] Re: [PATCH v17 08/15] seccomp: add system call filtering using BPF
Date: Tue, 10 Apr 2012 13:00:17 -0700 [thread overview]
Message-ID: <20120410130017.0d20e1b2.akpm@linux-foundation.org> (raw)
In-Reply-To: <CABqD9hYE0S4EL6yH-57SfNs+D8GFKJgWVN21VzXpQmRuh2ow=w@mail.gmail.com>
On Mon, 9 Apr 2012 14:59:00 -0500
Will Drewry <wad@chromium.org> wrote:
> >> I think this gives userspace an easy way of causing page allocation
> >> failure warnings, by permitting large kmalloc() attempts. __Add
> >> __GFP_NOWARN?
> >
> > Max is 32kb. sk_attach_filter() in net/core/filter.c is worse,
> > it allocates up to 512kb before even checking the length.
> >
> > What about using GFP_USER (and adding __GFP_NOWARN to GFP_USER) instead?
>
> It looks like GFP_USER|__GFP_NOWARN would make sense here. I'll change it.
I'm not really sure why GFP_USER exists. It's very rarely used, and
most usages are probably inappropriate. To me it means "same as
GFP_HIGHUSER, only don't use highmem". That's relevant to blockdev
pagecache and nothing else as far as I can tell. And good luck working
out what the __GFP_HARDWALL does ;)
This is a regular old allocation of kernel memory - the thing to use
here is GFP_KERNEL|__GFP_NOWARN.
(I'm surprised that we didn't remove __GFP_NOWARN ages ago - warning by
default is pretty obnoxious. But the warning continues to be
occasionally useful and false positives are rare).
WARNING: multiple messages have this Message-ID (diff)
From: Andrew Morton <akpm@linux-foundation.org>
To: Will Drewry <wad@chromium.org>
Cc: Indan Zupancic <indan@nul.nu>,
linux-kernel@vger.kernel.org,
linux-security-module@vger.kernel.org,
linux-arch@vger.kernel.org, linux-doc@vger.kernel.org,
kernel-hardening@lists.openwall.com, netdev@vger.kernel.org,
x86@kernel.org, arnd@arndb.de, davem@davemloft.net,
hpa@zytor.com, mingo@redhat.com, oleg@redhat.com,
peterz@infradead.org, rdunlap@xenotime.net,
mcgrathr@chromium.org, tglx@linutronix.de, luto@mit.edu,
eparis@redhat.com, serge.hallyn@canonical.com, djm@mindrot.org,
scarybeasts@gmail.com, pmoore@redhat.com, corbet@lwn.net,
eric.dumazet@gmail.com, markus@chromium.org,
coreyb@linux.vnet.ibm.com, keescook@chromium.org,
jmorris@namei.org
Subject: Re: [PATCH v17 08/15] seccomp: add system call filtering using BPF
Date: Tue, 10 Apr 2012 13:00:17 -0700 [thread overview]
Message-ID: <20120410130017.0d20e1b2.akpm@linux-foundation.org> (raw)
In-Reply-To: <CABqD9hYE0S4EL6yH-57SfNs+D8GFKJgWVN21VzXpQmRuh2ow=w@mail.gmail.com>
On Mon, 9 Apr 2012 14:59:00 -0500
Will Drewry <wad@chromium.org> wrote:
> >> I think this gives userspace an easy way of causing page allocation
> >> failure warnings, by permitting large kmalloc() attempts. __Add
> >> __GFP_NOWARN?
> >
> > Max is 32kb. sk_attach_filter() in net/core/filter.c is worse,
> > it allocates up to 512kb before even checking the length.
> >
> > What about using GFP_USER (and adding __GFP_NOWARN to GFP_USER) instead?
>
> It looks like GFP_USER|__GFP_NOWARN would make sense here. I'll change it.
I'm not really sure why GFP_USER exists. It's very rarely used, and
most usages are probably inappropriate. To me it means "same as
GFP_HIGHUSER, only don't use highmem". That's relevant to blockdev
pagecache and nothing else as far as I can tell. And good luck working
out what the __GFP_HARDWALL does ;)
This is a regular old allocation of kernel memory - the thing to use
here is GFP_KERNEL|__GFP_NOWARN.
(I'm surprised that we didn't remove __GFP_NOWARN ages ago - warning by
default is pretty obnoxious. But the warning continues to be
occasionally useful and false positives are rare).
next prev parent reply other threads:[~2012-04-10 20:00 UTC|newest]
Thread overview: 146+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-03-29 20:01 [kernel-hardening] [PATCH v17 00/15] seccomp_filter: BPF-based syscall filtering Will Drewry
2012-03-29 20:01 ` Will Drewry
2012-03-29 20:01 ` [kernel-hardening] [PATCH v17 01/15] Add PR_{GET,SET}_NO_NEW_PRIVS to prevent execve from granting privs Will Drewry
2012-03-29 20:01 ` Will Drewry
2012-04-06 19:49 ` [kernel-hardening] " Andrew Morton
2012-04-06 19:49 ` Andrew Morton
2012-04-06 19:55 ` [kernel-hardening] " Andy Lutomirski
2012-04-06 19:55 ` Andy Lutomirski
2012-04-06 19:55 ` Andy Lutomirski
2012-04-06 20:47 ` [kernel-hardening] " Markus Gutschke
2012-04-06 20:47 ` Markus Gutschke
2012-04-06 20:54 ` [kernel-hardening] " Andrew Lutomirski
2012-04-06 20:54 ` Andrew Lutomirski
2012-04-06 21:04 ` [kernel-hardening] " Markus Gutschke
2012-04-06 21:04 ` Markus Gutschke
2012-04-06 21:15 ` [kernel-hardening] " Andrew Lutomirski
2012-04-06 21:15 ` Andrew Lutomirski
2012-04-06 21:32 ` [kernel-hardening] " Markus Gutschke
2012-04-06 21:32 ` Markus Gutschke
2012-04-10 19:12 ` [kernel-hardening] " Will Drewry
2012-04-10 19:12 ` Will Drewry
2012-04-06 19:55 ` [kernel-hardening] " Andrew Morton
2012-04-06 19:55 ` Andrew Morton
2012-04-06 19:55 ` Andrew Morton
2012-04-06 20:01 ` [kernel-hardening] " Andrew Lutomirski
2012-04-06 20:01 ` Andrew Lutomirski
2012-04-06 20:28 ` [kernel-hardening] " Jonathan Corbet
2012-04-06 20:28 ` Jonathan Corbet
2012-04-06 20:37 ` [kernel-hardening] " Andrew Lutomirski
2012-04-06 20:37 ` Andrew Lutomirski
2012-04-11 19:31 ` [kernel-hardening] " Michael Kerrisk (man-pages)
2012-04-11 19:31 ` Michael Kerrisk (man-pages)
2012-04-12 0:15 ` [kernel-hardening] " Michael Kerrisk (man-pages)
2012-04-12 0:15 ` Michael Kerrisk (man-pages)
2012-04-12 0:50 ` [kernel-hardening] " Andrew Lutomirski
2012-04-12 0:50 ` Andrew Lutomirski
2012-04-16 19:11 ` [kernel-hardening] " Rob Landley
2012-04-16 19:11 ` Rob Landley
2012-04-10 20:37 ` [kernel-hardening] " Rob Landley
2012-04-10 20:37 ` Rob Landley
2012-04-10 19:03 ` [kernel-hardening] " Will Drewry
2012-04-10 19:03 ` Will Drewry
2012-03-29 20:01 ` [kernel-hardening] [PATCH v17 02/15] Fix apparmor for PR_{GET,SET}_NO_NEW_PRIVS Will Drewry
2012-03-29 20:01 ` Will Drewry
2012-03-29 20:01 ` [kernel-hardening] [PATCH v17 03/15] sk_run_filter: add BPF_S_ANC_SECCOMP_LD_W Will Drewry
2012-03-29 20:01 ` Will Drewry
2012-03-29 20:01 ` [kernel-hardening] [PATCH v17 04/15] net/compat.c,linux/filter.h: share compat_sock_fprog Will Drewry
2012-03-29 20:01 ` Will Drewry
2012-03-29 20:01 ` [kernel-hardening] [PATCH v17 05/15] seccomp: kill the seccomp_t typedef Will Drewry
2012-03-29 20:01 ` Will Drewry
2012-03-29 20:01 ` [kernel-hardening] [PATCH v17 06/15] arch/x86: add syscall_get_arch to syscall.h Will Drewry
2012-03-29 20:01 ` Will Drewry
2012-03-29 20:01 ` [kernel-hardening] [PATCH v17 07/15] asm/syscall.h: add syscall_get_arch Will Drewry
2012-03-29 20:01 ` Will Drewry
2012-04-06 20:05 ` [kernel-hardening] " Andrew Morton
2012-04-06 20:05 ` Andrew Morton
2012-04-09 19:24 ` [kernel-hardening] " Will Drewry
2012-04-09 19:24 ` Will Drewry
2012-03-29 20:01 ` [kernel-hardening] [PATCH v17 08/15] seccomp: add system call filtering using BPF Will Drewry
2012-03-29 20:01 ` Will Drewry
2012-03-31 4:40 ` [kernel-hardening] " Vladimir Murzin
2012-03-31 4:40 ` Vladimir Murzin
2012-03-31 18:14 ` [kernel-hardening] " Will Drewry
2012-03-31 18:14 ` Will Drewry
2012-04-06 20:23 ` [kernel-hardening] " Andrew Morton
2012-04-06 20:23 ` Andrew Morton
2012-04-06 20:44 ` [kernel-hardening] " Kees Cook
2012-04-06 20:44 ` Kees Cook
2012-04-06 21:05 ` [kernel-hardening] " Andrew Morton
2012-04-06 21:05 ` Andrew Morton
2012-04-06 21:06 ` [kernel-hardening] " H. Peter Anvin
2012-04-06 21:06 ` H. Peter Anvin
2012-04-06 21:09 ` [kernel-hardening] " Andrew Morton
2012-04-06 21:09 ` Andrew Morton
2012-04-08 18:22 ` [kernel-hardening] " Indan Zupancic
2012-04-08 18:22 ` Indan Zupancic
2012-04-09 19:59 ` [kernel-hardening] " Will Drewry
2012-04-09 19:59 ` Will Drewry
2012-04-10 9:48 ` [kernel-hardening] " James Morris
2012-04-10 9:48 ` James Morris
2012-04-10 20:00 ` Andrew Morton [this message]
2012-04-10 20:00 ` Andrew Morton
2012-04-10 20:16 ` [kernel-hardening] " Will Drewry
2012-04-10 20:16 ` Will Drewry
2012-04-10 20:16 ` Will Drewry
2012-04-10 10:34 ` [kernel-hardening] " Eric Dumazet
2012-04-10 10:34 ` Eric Dumazet
2012-04-10 19:54 ` [kernel-hardening] " Andrew Morton
2012-04-10 19:54 ` Andrew Morton
2012-04-10 20:15 ` [kernel-hardening] " Will Drewry
2012-04-10 20:15 ` Will Drewry
2012-03-29 20:01 ` [kernel-hardening] [PATCH v17 09/15] seccomp: remove duplicated failure logging Will Drewry
2012-03-29 20:01 ` Will Drewry
2012-04-06 21:14 ` [kernel-hardening] " Andrew Morton
2012-04-06 21:14 ` Andrew Morton
2012-04-09 19:26 ` [kernel-hardening] " Will Drewry
2012-04-09 19:26 ` Will Drewry
2012-04-09 19:26 ` Will Drewry
2012-04-09 19:32 ` [kernel-hardening] " Kees Cook
2012-04-09 19:32 ` Kees Cook
2012-04-09 19:33 ` [kernel-hardening] " Eric Paris
2012-04-09 19:33 ` Eric Paris
2012-04-09 19:39 ` [kernel-hardening] " Kees Cook
2012-04-09 19:39 ` Kees Cook
2012-03-29 20:01 ` [kernel-hardening] [PATCH v17 10/15] seccomp: add SECCOMP_RET_ERRNO Will Drewry
2012-03-29 20:01 ` Will Drewry
2012-04-06 21:19 ` [kernel-hardening] " Andrew Morton
2012-04-06 21:19 ` Andrew Morton
2012-04-09 19:19 ` [kernel-hardening] " Will Drewry
2012-04-09 19:19 ` Will Drewry
2012-03-29 20:01 ` [kernel-hardening] [PATCH v17 11/15] signal, x86: add SIGSYS info and make it synchronous Will Drewry
2012-03-29 20:01 ` Will Drewry
2012-03-29 20:01 ` [kernel-hardening] [PATCH v17 12/15] seccomp: Add SECCOMP_RET_TRAP Will Drewry
2012-03-29 20:01 ` Will Drewry
2012-03-29 20:01 ` [kernel-hardening] [PATCH v17 13/15] ptrace,seccomp: Add PTRACE_SECCOMP support Will Drewry
2012-03-29 20:01 ` Will Drewry
2012-04-06 21:24 ` [kernel-hardening] " Andrew Morton
2012-04-06 21:24 ` Andrew Morton
2012-04-09 19:38 ` [kernel-hardening] " Will Drewry
2012-04-09 19:38 ` Will Drewry
2012-03-29 20:01 ` [kernel-hardening] [PATCH v17 14/15] x86: Enable HAVE_ARCH_SECCOMP_FILTER Will Drewry
2012-03-29 20:01 ` Will Drewry
2012-03-29 20:02 ` [kernel-hardening] [PATCH v17 15/15] Documentation: prctl/seccomp_filter Will Drewry
2012-03-29 20:02 ` Will Drewry
2012-04-06 21:26 ` [kernel-hardening] " Andrew Morton
2012-04-06 21:26 ` Andrew Morton
2012-04-09 19:46 ` [kernel-hardening] " Will Drewry
2012-04-09 19:46 ` Will Drewry
2012-04-09 20:47 ` [kernel-hardening] " Markus Gutschke
2012-04-09 20:47 ` Markus Gutschke
2012-04-09 20:58 ` [kernel-hardening] " Ryan Ware
2012-04-09 20:58 ` Ryan Ware
2012-04-09 20:58 ` Ryan Ware
2012-04-09 22:47 ` [kernel-hardening] " Will Drewry
2012-04-09 22:47 ` Will Drewry
2012-04-10 17:49 ` [kernel-hardening] " Ryan Ware
2012-04-10 17:49 ` Ryan Ware
2012-04-10 17:49 ` Ryan Ware
2012-03-29 23:11 ` [kernel-hardening] Re: [PATCH v17 00/15] seccomp_filter: BPF-based syscall filtering James Morris
2012-03-29 23:11 ` James Morris
2012-04-06 21:28 ` [kernel-hardening] " Andrew Morton
2012-04-06 21:28 ` Andrew Morton
2012-04-06 21:28 ` Andrew Morton
2012-04-09 3:48 ` [kernel-hardening] " James Morris
2012-04-09 3:48 ` James Morris
2012-04-09 3:48 ` James Morris
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