From: Mark Rutland <mark.rutland@arm.com>
To: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: wsd_upstream@mediatek.com,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will.deacon@arm.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Miles Chen <miles.chen@mediatek.com>,
linux-mediatek@lists.infradead.org, labbott@redhat.com,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH] arm64: dump: hide kernel pointers
Date: Tue, 28 Feb 2017 10:04:20 +0000 [thread overview]
Message-ID: <20170228100420.GA3691@leverpostej> (raw)
In-Reply-To: <CAKv+Gu_AG0n5jPDCuUD6tvr2sAz9a4sycDy9CtL4iT+OHiN_iQ@mail.gmail.com>
On Tue, Feb 28, 2017 at 08:42:51AM +0000, Ard Biesheuvel wrote:
> (+ Mark)
(+ Laura)
> On 28 February 2017 at 07:05, Miles Chen <miles.chen@mediatek.com> wrote:
> > Mask kernel pointers of /sys/kernel/debug/kernel_page_tables entry like
> > /proc/vmallocinfo does.
> >
> > With sysctl kernel.kptr_restrict=0 or 1:
> > cat /sys/kernel/debug/kernel_page_tables
>
> I wonder if this file should be accessible at all if kptr_restrict > 0
I don't have strong feelings either way.
This isn't typically enabled, and it's under debugfs, so this shouldn't
be accessible by a typical user anyhow.
That said, there are very few of us who need to take a look at this
file. I'm happy to deal with attacking kptr_restrict when required.
Thanks,
Mark.
> > ---[ Modules start ]---
> > ---[ Modules end ]---
> > ---[ vmalloc() Area ]---
> > ffffff8008000000-ffffff8008010000 64K PTE RW NX SHD AF...
> > ffffff8008015000-ffffff8008016000 4K PTE RW NX SHD AF...
> > ffffff8008020000-ffffff8008030000 64K PTE RW NX SHD AF...
> > ffffff8008031000-ffffff8008071000 256K PTE RW NX SHD AF...
> > ffffff8008080000-ffffff8008200000 1536K PTE ro x SHD AF...
> > ffffff8008200000-ffffff8008400000 2M PMD ro x SHD AF...
> > ffffff8008400000-ffffff8008540000 1280K PTE ro x SHD AF...
> > ffffff8008540000-ffffff8008690000 1344K PTE ro NX SHD AF...
> > ffffff8008940000-ffffff8008a10000 832K PTE RW NX SHD AF...
> > ffffff8008aca000-ffffff8008acd000 12K PTE RW NX SHD AF...
> > ffffffbebffd8000-ffffffbebffdb000 12K PTE RW NX SHD AF...
> > ---[ vmalloc() End ]---
> > ---[ Fixmap start ]---
> > ffffffbefe800000-ffffffbefea00000 2M PMD ro NX SHD AF...
> > ---[ Fixmap end ]---
> > ---[ PCI I/O start ]---
> > ---[ PCI I/O end ]---
> > ---[ Linear Mapping ]---
> > ffffffc000000000-ffffffc000080000 512K PTE RW NX SHD AF...
> > ffffffc000080000-ffffffc000200000 1536K PTE ro NX SHD AF...
> > ffffffc000200000-ffffffc000600000 4M PMD ro NX SHD AF...
> > ffffffc000600000-ffffffc000690000 576K PTE ro NX SHD AF...
> > ffffffc000690000-ffffffc000800000 1472K PTE RW NX SHD AF...
> > ffffffc000800000-ffffffc002000000 24M PMD RW NX SHD AF...
> > ffffffc002000000-ffffffc040000000 992M PMD RW NX SHD AF...
> > ffffffc040000000-ffffffc080000000 1G PGD RW NX SHD AF...
> >
> > With sysctl kernel.kptr_restrict=2:
> > cat /sys/kernel/debug/kernel_page_tables
> > ---[ Modules start ]---
> > ---[ Modules end ]---
> > ---[ vmalloc() Area ]---
> > 0000000000000000-0000000000000000 64K PTE RW NX SHD AF...
> > 0000000000000000-0000000000000000 4K PTE RW NX SHD AF...
> > 0000000000000000-0000000000000000 64K PTE RW NX SHD AF...
> > 0000000000000000-0000000000000000 256K PTE RW NX SHD AF...
> > 0000000000000000-0000000000000000 1536K PTE ro x SHD AF...
> > 0000000000000000-0000000000000000 2M PMD ro x SHD AF...
> > 0000000000000000-0000000000000000 1280K PTE ro x SHD AF...
> > 0000000000000000-0000000000000000 1344K PTE ro NX SHD AF...
> > 0000000000000000-0000000000000000 832K PTE RW NX SHD AF...
> > 0000000000000000-0000000000000000 12K PTE RW NX SHD AF...
> > 0000000000000000-0000000000000000 12K PTE RW NX SHD AF...
> > ---[ vmalloc() End ]---
> > ---[ Fixmap start ]---
> > 0000000000000000-0000000000000000 2M PMD ro NX SHD AF...
> > ---[ Fixmap end ]---
> > ---[ PCI I/O start ]---
> > ---[ PCI I/O end ]---
> > ---[ Linear Mapping ]---
> > 0000000000000000-0000000000000000 512K PTE RW NX SHD AF...
> > 0000000000000000-0000000000000000 1536K PTE ro NX SHD AF...
> > 0000000000000000-0000000000000000 4M PMD ro NX SHD AF...
> > 0000000000000000-0000000000000000 576K PTE ro NX SHD AF...
> > 0000000000000000-0000000000000000 1472K PTE RW NX SHD AF...
> > 0000000000000000-0000000000000000 24M PMD RW NX SHD AF...
> > 0000000000000000-0000000000000000 992M PMD RW NX SHD AF...
> > 0000000000000000-0000000000000000 1G PGD RW NX SHD AF...
> >
> > Signed-off-by: Miles Chen <miles.chen@mediatek.com>
> > ---
> > arch/arm64/mm/dump.c | 4 ++--
> > 1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/arch/arm64/mm/dump.c b/arch/arm64/mm/dump.c
> > index ca74a2a..e055ecf 100644
> > --- a/arch/arm64/mm/dump.c
> > +++ b/arch/arm64/mm/dump.c
> > @@ -253,8 +253,8 @@ static void note_page(struct pg_state *st, unsigned long addr, unsigned level,
> > if (st->current_prot) {
> > note_prot_uxn(st, addr);
> > note_prot_wx(st, addr);
> > - pt_dump_seq_printf(st->seq, "0x%016lx-0x%016lx ",
> > - st->start_address, addr);
> > + pt_dump_seq_printf(st->seq, "%pK-%pK ",
> > + (void *)st->start_address, (void *)addr);
> >
> > delta = (addr - st->start_address) >> 10;
> > while (!(delta & 1023) && unit[1]) {
> > --
> > 1.9.1
> >
> >
> > _______________________________________________
> > linux-arm-kernel mailing list
> > linux-arm-kernel@lists.infradead.org
> > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
WARNING: multiple messages have this Message-ID (diff)
From: mark.rutland@arm.com (Mark Rutland)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] arm64: dump: hide kernel pointers
Date: Tue, 28 Feb 2017 10:04:20 +0000 [thread overview]
Message-ID: <20170228100420.GA3691@leverpostej> (raw)
In-Reply-To: <CAKv+Gu_AG0n5jPDCuUD6tvr2sAz9a4sycDy9CtL4iT+OHiN_iQ@mail.gmail.com>
On Tue, Feb 28, 2017 at 08:42:51AM +0000, Ard Biesheuvel wrote:
> (+ Mark)
(+ Laura)
> On 28 February 2017 at 07:05, Miles Chen <miles.chen@mediatek.com> wrote:
> > Mask kernel pointers of /sys/kernel/debug/kernel_page_tables entry like
> > /proc/vmallocinfo does.
> >
> > With sysctl kernel.kptr_restrict=0 or 1:
> > cat /sys/kernel/debug/kernel_page_tables
>
> I wonder if this file should be accessible at all if kptr_restrict > 0
I don't have strong feelings either way.
This isn't typically enabled, and it's under debugfs, so this shouldn't
be accessible by a typical user anyhow.
That said, there are very few of us who need to take a look at this
file. I'm happy to deal with attacking kptr_restrict when required.
Thanks,
Mark.
> > ---[ Modules start ]---
> > ---[ Modules end ]---
> > ---[ vmalloc() Area ]---
> > ffffff8008000000-ffffff8008010000 64K PTE RW NX SHD AF...
> > ffffff8008015000-ffffff8008016000 4K PTE RW NX SHD AF...
> > ffffff8008020000-ffffff8008030000 64K PTE RW NX SHD AF...
> > ffffff8008031000-ffffff8008071000 256K PTE RW NX SHD AF...
> > ffffff8008080000-ffffff8008200000 1536K PTE ro x SHD AF...
> > ffffff8008200000-ffffff8008400000 2M PMD ro x SHD AF...
> > ffffff8008400000-ffffff8008540000 1280K PTE ro x SHD AF...
> > ffffff8008540000-ffffff8008690000 1344K PTE ro NX SHD AF...
> > ffffff8008940000-ffffff8008a10000 832K PTE RW NX SHD AF...
> > ffffff8008aca000-ffffff8008acd000 12K PTE RW NX SHD AF...
> > ffffffbebffd8000-ffffffbebffdb000 12K PTE RW NX SHD AF...
> > ---[ vmalloc() End ]---
> > ---[ Fixmap start ]---
> > ffffffbefe800000-ffffffbefea00000 2M PMD ro NX SHD AF...
> > ---[ Fixmap end ]---
> > ---[ PCI I/O start ]---
> > ---[ PCI I/O end ]---
> > ---[ Linear Mapping ]---
> > ffffffc000000000-ffffffc000080000 512K PTE RW NX SHD AF...
> > ffffffc000080000-ffffffc000200000 1536K PTE ro NX SHD AF...
> > ffffffc000200000-ffffffc000600000 4M PMD ro NX SHD AF...
> > ffffffc000600000-ffffffc000690000 576K PTE ro NX SHD AF...
> > ffffffc000690000-ffffffc000800000 1472K PTE RW NX SHD AF...
> > ffffffc000800000-ffffffc002000000 24M PMD RW NX SHD AF...
> > ffffffc002000000-ffffffc040000000 992M PMD RW NX SHD AF...
> > ffffffc040000000-ffffffc080000000 1G PGD RW NX SHD AF...
> >
> > With sysctl kernel.kptr_restrict=2:
> > cat /sys/kernel/debug/kernel_page_tables
> > ---[ Modules start ]---
> > ---[ Modules end ]---
> > ---[ vmalloc() Area ]---
> > 0000000000000000-0000000000000000 64K PTE RW NX SHD AF...
> > 0000000000000000-0000000000000000 4K PTE RW NX SHD AF...
> > 0000000000000000-0000000000000000 64K PTE RW NX SHD AF...
> > 0000000000000000-0000000000000000 256K PTE RW NX SHD AF...
> > 0000000000000000-0000000000000000 1536K PTE ro x SHD AF...
> > 0000000000000000-0000000000000000 2M PMD ro x SHD AF...
> > 0000000000000000-0000000000000000 1280K PTE ro x SHD AF...
> > 0000000000000000-0000000000000000 1344K PTE ro NX SHD AF...
> > 0000000000000000-0000000000000000 832K PTE RW NX SHD AF...
> > 0000000000000000-0000000000000000 12K PTE RW NX SHD AF...
> > 0000000000000000-0000000000000000 12K PTE RW NX SHD AF...
> > ---[ vmalloc() End ]---
> > ---[ Fixmap start ]---
> > 0000000000000000-0000000000000000 2M PMD ro NX SHD AF...
> > ---[ Fixmap end ]---
> > ---[ PCI I/O start ]---
> > ---[ PCI I/O end ]---
> > ---[ Linear Mapping ]---
> > 0000000000000000-0000000000000000 512K PTE RW NX SHD AF...
> > 0000000000000000-0000000000000000 1536K PTE ro NX SHD AF...
> > 0000000000000000-0000000000000000 4M PMD ro NX SHD AF...
> > 0000000000000000-0000000000000000 576K PTE ro NX SHD AF...
> > 0000000000000000-0000000000000000 1472K PTE RW NX SHD AF...
> > 0000000000000000-0000000000000000 24M PMD RW NX SHD AF...
> > 0000000000000000-0000000000000000 992M PMD RW NX SHD AF...
> > 0000000000000000-0000000000000000 1G PGD RW NX SHD AF...
> >
> > Signed-off-by: Miles Chen <miles.chen@mediatek.com>
> > ---
> > arch/arm64/mm/dump.c | 4 ++--
> > 1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/arch/arm64/mm/dump.c b/arch/arm64/mm/dump.c
> > index ca74a2a..e055ecf 100644
> > --- a/arch/arm64/mm/dump.c
> > +++ b/arch/arm64/mm/dump.c
> > @@ -253,8 +253,8 @@ static void note_page(struct pg_state *st, unsigned long addr, unsigned level,
> > if (st->current_prot) {
> > note_prot_uxn(st, addr);
> > note_prot_wx(st, addr);
> > - pt_dump_seq_printf(st->seq, "0x%016lx-0x%016lx ",
> > - st->start_address, addr);
> > + pt_dump_seq_printf(st->seq, "%pK-%pK ",
> > + (void *)st->start_address, (void *)addr);
> >
> > delta = (addr - st->start_address) >> 10;
> > while (!(delta & 1023) && unit[1]) {
> > --
> > 1.9.1
> >
> >
> > _______________________________________________
> > linux-arm-kernel mailing list
> > linux-arm-kernel at lists.infradead.org
> > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
WARNING: multiple messages have this Message-ID (diff)
From: Mark Rutland <mark.rutland@arm.com>
To: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Miles Chen <miles.chen@mediatek.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will.deacon@arm.com>,
linux-mediatek@lists.infradead.org,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
wsd_upstream@mediatek.com, labbott@redhat.com
Subject: Re: [PATCH] arm64: dump: hide kernel pointers
Date: Tue, 28 Feb 2017 10:04:20 +0000 [thread overview]
Message-ID: <20170228100420.GA3691@leverpostej> (raw)
In-Reply-To: <CAKv+Gu_AG0n5jPDCuUD6tvr2sAz9a4sycDy9CtL4iT+OHiN_iQ@mail.gmail.com>
On Tue, Feb 28, 2017 at 08:42:51AM +0000, Ard Biesheuvel wrote:
> (+ Mark)
(+ Laura)
> On 28 February 2017 at 07:05, Miles Chen <miles.chen@mediatek.com> wrote:
> > Mask kernel pointers of /sys/kernel/debug/kernel_page_tables entry like
> > /proc/vmallocinfo does.
> >
> > With sysctl kernel.kptr_restrict=0 or 1:
> > cat /sys/kernel/debug/kernel_page_tables
>
> I wonder if this file should be accessible at all if kptr_restrict > 0
I don't have strong feelings either way.
This isn't typically enabled, and it's under debugfs, so this shouldn't
be accessible by a typical user anyhow.
That said, there are very few of us who need to take a look at this
file. I'm happy to deal with attacking kptr_restrict when required.
Thanks,
Mark.
> > ---[ Modules start ]---
> > ---[ Modules end ]---
> > ---[ vmalloc() Area ]---
> > ffffff8008000000-ffffff8008010000 64K PTE RW NX SHD AF...
> > ffffff8008015000-ffffff8008016000 4K PTE RW NX SHD AF...
> > ffffff8008020000-ffffff8008030000 64K PTE RW NX SHD AF...
> > ffffff8008031000-ffffff8008071000 256K PTE RW NX SHD AF...
> > ffffff8008080000-ffffff8008200000 1536K PTE ro x SHD AF...
> > ffffff8008200000-ffffff8008400000 2M PMD ro x SHD AF...
> > ffffff8008400000-ffffff8008540000 1280K PTE ro x SHD AF...
> > ffffff8008540000-ffffff8008690000 1344K PTE ro NX SHD AF...
> > ffffff8008940000-ffffff8008a10000 832K PTE RW NX SHD AF...
> > ffffff8008aca000-ffffff8008acd000 12K PTE RW NX SHD AF...
> > ffffffbebffd8000-ffffffbebffdb000 12K PTE RW NX SHD AF...
> > ---[ vmalloc() End ]---
> > ---[ Fixmap start ]---
> > ffffffbefe800000-ffffffbefea00000 2M PMD ro NX SHD AF...
> > ---[ Fixmap end ]---
> > ---[ PCI I/O start ]---
> > ---[ PCI I/O end ]---
> > ---[ Linear Mapping ]---
> > ffffffc000000000-ffffffc000080000 512K PTE RW NX SHD AF...
> > ffffffc000080000-ffffffc000200000 1536K PTE ro NX SHD AF...
> > ffffffc000200000-ffffffc000600000 4M PMD ro NX SHD AF...
> > ffffffc000600000-ffffffc000690000 576K PTE ro NX SHD AF...
> > ffffffc000690000-ffffffc000800000 1472K PTE RW NX SHD AF...
> > ffffffc000800000-ffffffc002000000 24M PMD RW NX SHD AF...
> > ffffffc002000000-ffffffc040000000 992M PMD RW NX SHD AF...
> > ffffffc040000000-ffffffc080000000 1G PGD RW NX SHD AF...
> >
> > With sysctl kernel.kptr_restrict=2:
> > cat /sys/kernel/debug/kernel_page_tables
> > ---[ Modules start ]---
> > ---[ Modules end ]---
> > ---[ vmalloc() Area ]---
> > 0000000000000000-0000000000000000 64K PTE RW NX SHD AF...
> > 0000000000000000-0000000000000000 4K PTE RW NX SHD AF...
> > 0000000000000000-0000000000000000 64K PTE RW NX SHD AF...
> > 0000000000000000-0000000000000000 256K PTE RW NX SHD AF...
> > 0000000000000000-0000000000000000 1536K PTE ro x SHD AF...
> > 0000000000000000-0000000000000000 2M PMD ro x SHD AF...
> > 0000000000000000-0000000000000000 1280K PTE ro x SHD AF...
> > 0000000000000000-0000000000000000 1344K PTE ro NX SHD AF...
> > 0000000000000000-0000000000000000 832K PTE RW NX SHD AF...
> > 0000000000000000-0000000000000000 12K PTE RW NX SHD AF...
> > 0000000000000000-0000000000000000 12K PTE RW NX SHD AF...
> > ---[ vmalloc() End ]---
> > ---[ Fixmap start ]---
> > 0000000000000000-0000000000000000 2M PMD ro NX SHD AF...
> > ---[ Fixmap end ]---
> > ---[ PCI I/O start ]---
> > ---[ PCI I/O end ]---
> > ---[ Linear Mapping ]---
> > 0000000000000000-0000000000000000 512K PTE RW NX SHD AF...
> > 0000000000000000-0000000000000000 1536K PTE ro NX SHD AF...
> > 0000000000000000-0000000000000000 4M PMD ro NX SHD AF...
> > 0000000000000000-0000000000000000 576K PTE ro NX SHD AF...
> > 0000000000000000-0000000000000000 1472K PTE RW NX SHD AF...
> > 0000000000000000-0000000000000000 24M PMD RW NX SHD AF...
> > 0000000000000000-0000000000000000 992M PMD RW NX SHD AF...
> > 0000000000000000-0000000000000000 1G PGD RW NX SHD AF...
> >
> > Signed-off-by: Miles Chen <miles.chen@mediatek.com>
> > ---
> > arch/arm64/mm/dump.c | 4 ++--
> > 1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/arch/arm64/mm/dump.c b/arch/arm64/mm/dump.c
> > index ca74a2a..e055ecf 100644
> > --- a/arch/arm64/mm/dump.c
> > +++ b/arch/arm64/mm/dump.c
> > @@ -253,8 +253,8 @@ static void note_page(struct pg_state *st, unsigned long addr, unsigned level,
> > if (st->current_prot) {
> > note_prot_uxn(st, addr);
> > note_prot_wx(st, addr);
> > - pt_dump_seq_printf(st->seq, "0x%016lx-0x%016lx ",
> > - st->start_address, addr);
> > + pt_dump_seq_printf(st->seq, "%pK-%pK ",
> > + (void *)st->start_address, (void *)addr);
> >
> > delta = (addr - st->start_address) >> 10;
> > while (!(delta & 1023) && unit[1]) {
> > --
> > 1.9.1
> >
> >
> > _______________________________________________
> > linux-arm-kernel mailing list
> > linux-arm-kernel@lists.infradead.org
> > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2017-02-28 10:04 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-02-28 7:05 [PATCH] arm64: dump: hide kernel pointers Miles Chen
2017-02-28 7:05 ` Miles Chen
2017-02-28 7:05 ` Miles Chen
2017-02-28 8:42 ` Ard Biesheuvel
2017-02-28 8:42 ` Ard Biesheuvel
2017-02-28 8:42 ` Ard Biesheuvel
2017-02-28 10:04 ` Mark Rutland [this message]
2017-02-28 10:04 ` Mark Rutland
2017-02-28 10:04 ` Mark Rutland
2017-02-28 22:55 ` Laura Abbott
2017-02-28 22:55 ` Laura Abbott
2017-02-28 22:55 ` Laura Abbott
2017-03-01 3:52 ` Will Deacon
2017-03-01 3:52 ` Will Deacon
2017-03-01 3:52 ` Will Deacon
[not found] ` <20170301035214.GA12637-5wv7dgnIgG8@public.gmane.org>
2017-03-01 15:18 ` Laura Abbott
2017-03-01 15:18 ` Laura Abbott
2017-03-01 15:18 ` Laura Abbott
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=20170228100420.GA3691@leverpostej \
--to=mark.rutland@arm.com \
--cc=ard.biesheuvel@linaro.org \
--cc=catalin.marinas@arm.com \
--cc=labbott@redhat.com \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mediatek@lists.infradead.org \
--cc=miles.chen@mediatek.com \
--cc=will.deacon@arm.com \
--cc=wsd_upstream@mediatek.com \
/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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.