* [PATCH] x86/mm/init: Stop printing pgt_buf addresses
@ 2020-02-29 23:11 Arvind Sankar
2020-02-29 23:23 ` Kees Cook
` (3 more replies)
0 siblings, 4 replies; 8+ messages in thread
From: Arvind Sankar @ 2020-02-29 23:11 UTC (permalink / raw)
To: Tobin C . Harding, Tycho Andersen
Cc: kernel-hardening, Kees Cook, Dave Hansen, Andy Lutomirski,
Peter Zijlstra, x86, linux-kernel
This currently leaks kernel physical addresses into userspace.
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
---
arch/x86/mm/init.c | 2 --
1 file changed, 2 deletions(-)
diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c
index e7bb483557c9..dc4711f09cdc 100644
--- a/arch/x86/mm/init.c
+++ b/arch/x86/mm/init.c
@@ -121,8 +121,6 @@ __ref void *alloc_low_pages(unsigned int num)
} else {
pfn = pgt_buf_end;
pgt_buf_end += num;
- printk(KERN_DEBUG "BRK [%#010lx, %#010lx] PGTABLE\n",
- pfn << PAGE_SHIFT, (pgt_buf_end << PAGE_SHIFT) - 1);
}
for (i = 0; i < num; i++) {
--
2.24.1
^ permalink raw reply related [flat|nested] 8+ messages in thread
* Re: [PATCH] x86/mm/init: Stop printing pgt_buf addresses
2020-02-29 23:11 [PATCH] x86/mm/init: Stop printing pgt_buf addresses Arvind Sankar
@ 2020-02-29 23:23 ` Kees Cook
2020-04-09 22:19 ` Arvind Sankar
` (2 subsequent siblings)
3 siblings, 0 replies; 8+ messages in thread
From: Kees Cook @ 2020-02-29 23:23 UTC (permalink / raw)
To: x86
Cc: Arvind Sankar, Tobin C . Harding, Tycho Andersen,
kernel-hardening, Dave Hansen, Andy Lutomirski, Peter Zijlstra,
linux-kernel
On Sat, Feb 29, 2020 at 06:11:20PM -0500, Arvind Sankar wrote:
> This currently leaks kernel physical addresses into userspace.
>
> Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Acked-by: Kees Cook <keescook@chromium.org>
-Kees
> ---
> arch/x86/mm/init.c | 2 --
> 1 file changed, 2 deletions(-)
>
> diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c
> index e7bb483557c9..dc4711f09cdc 100644
> --- a/arch/x86/mm/init.c
> +++ b/arch/x86/mm/init.c
> @@ -121,8 +121,6 @@ __ref void *alloc_low_pages(unsigned int num)
> } else {
> pfn = pgt_buf_end;
> pgt_buf_end += num;
> - printk(KERN_DEBUG "BRK [%#010lx, %#010lx] PGTABLE\n",
> - pfn << PAGE_SHIFT, (pgt_buf_end << PAGE_SHIFT) - 1);
> }
>
> for (i = 0; i < num; i++) {
> --
> 2.24.1
>
--
Kees Cook
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] x86/mm/init: Stop printing pgt_buf addresses
2020-02-29 23:11 [PATCH] x86/mm/init: Stop printing pgt_buf addresses Arvind Sankar
2020-02-29 23:23 ` Kees Cook
@ 2020-04-09 22:19 ` Arvind Sankar
2020-04-09 22:35 ` Dave Hansen
2020-05-23 1:51 ` Arvind Sankar
2020-05-23 7:41 ` [tip: x86/cleanups] x86/mm: Stop printing BRK addresses tip-bot2 for Arvind Sankar
3 siblings, 1 reply; 8+ messages in thread
From: Arvind Sankar @ 2020-04-09 22:19 UTC (permalink / raw)
To: Arvind Sankar
Cc: Tobin C . Harding, Tycho Andersen, kernel-hardening, Kees Cook,
Dave Hansen, Andy Lutomirski, Peter Zijlstra, x86, linux-kernel
On Sat, Feb 29, 2020 at 06:11:20PM -0500, Arvind Sankar wrote:
> This currently leaks kernel physical addresses into userspace.
>
> Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
> ---
> arch/x86/mm/init.c | 2 --
> 1 file changed, 2 deletions(-)
>
> diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c
> index e7bb483557c9..dc4711f09cdc 100644
> --- a/arch/x86/mm/init.c
> +++ b/arch/x86/mm/init.c
> @@ -121,8 +121,6 @@ __ref void *alloc_low_pages(unsigned int num)
> } else {
> pfn = pgt_buf_end;
> pgt_buf_end += num;
> - printk(KERN_DEBUG "BRK [%#010lx, %#010lx] PGTABLE\n",
> - pfn << PAGE_SHIFT, (pgt_buf_end << PAGE_SHIFT) - 1);
> }
>
> for (i = 0; i < num; i++) {
> --
> 2.24.1
>
This was acked by Kees, is it ok for merge?
Thanks.
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] x86/mm/init: Stop printing pgt_buf addresses
2020-04-09 22:19 ` Arvind Sankar
@ 2020-04-09 22:35 ` Dave Hansen
0 siblings, 0 replies; 8+ messages in thread
From: Dave Hansen @ 2020-04-09 22:35 UTC (permalink / raw)
To: Arvind Sankar
Cc: Tobin C . Harding, Tycho Andersen, kernel-hardening, Kees Cook,
Andy Lutomirski, Peter Zijlstra, x86, linux-kernel
On 4/9/20 3:19 PM, Arvind Sankar wrote:
>> @@ -121,8 +121,6 @@ __ref void *alloc_low_pages(unsigned int num)
>> } else {
>> pfn = pgt_buf_end;
>> pgt_buf_end += num;
>> - printk(KERN_DEBUG "BRK [%#010lx, %#010lx] PGTABLE\n",
>> - pfn << PAGE_SHIFT, (pgt_buf_end << PAGE_SHIFT) - 1);
>> }
>>
>> for (i = 0; i < num; i++) {
>> --
>> 2.24.1
>>
> This was acked by Kees, is it ok for merge?
Independent of the obvious security implications, I don't think I've
ever once gleaned useful information from that message. It's fine by me.
Acked-by: Dave Hansen <dave.hansen@intel.com>
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] x86/mm/init: Stop printing pgt_buf addresses
2020-02-29 23:11 [PATCH] x86/mm/init: Stop printing pgt_buf addresses Arvind Sankar
2020-02-29 23:23 ` Kees Cook
2020-04-09 22:19 ` Arvind Sankar
@ 2020-05-23 1:51 ` Arvind Sankar
2020-05-23 2:57 ` Joe Perches
2020-05-23 7:41 ` [tip: x86/cleanups] x86/mm: Stop printing BRK addresses tip-bot2 for Arvind Sankar
3 siblings, 1 reply; 8+ messages in thread
From: Arvind Sankar @ 2020-05-23 1:51 UTC (permalink / raw)
To: Arvind Sankar
Cc: Tobin C . Harding, Tycho Andersen, kernel-hardening, Kees Cook,
Dave Hansen, Andy Lutomirski, Peter Zijlstra, x86, linux-kernel
On Sat, Feb 29, 2020 at 06:11:20PM -0500, Arvind Sankar wrote:
> This currently leaks kernel physical addresses into userspace.
>
> Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
> ---
> arch/x86/mm/init.c | 2 --
> 1 file changed, 2 deletions(-)
>
> diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c
> index e7bb483557c9..dc4711f09cdc 100644
> --- a/arch/x86/mm/init.c
> +++ b/arch/x86/mm/init.c
> @@ -121,8 +121,6 @@ __ref void *alloc_low_pages(unsigned int num)
> } else {
> pfn = pgt_buf_end;
> pgt_buf_end += num;
> - printk(KERN_DEBUG "BRK [%#010lx, %#010lx] PGTABLE\n",
> - pfn << PAGE_SHIFT, (pgt_buf_end << PAGE_SHIFT) - 1);
> }
>
> for (i = 0; i < num; i++) {
> --
> 2.24.1
>
Ping.
https://lore.kernel.org/lkml/20200229231120.1147527-1-nivedita@alum.mit.edu/
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] x86/mm/init: Stop printing pgt_buf addresses
2020-05-23 1:51 ` Arvind Sankar
@ 2020-05-23 2:57 ` Joe Perches
0 siblings, 0 replies; 8+ messages in thread
From: Joe Perches @ 2020-05-23 2:57 UTC (permalink / raw)
To: Arvind Sankar
Cc: Tobin C . Harding, Tycho Andersen, kernel-hardening, Kees Cook,
Dave Hansen, Andy Lutomirski, Peter Zijlstra, x86, linux-kernel
On Fri, 2020-05-22 at 21:51 -0400, Arvind Sankar wrote:
> On Sat, Feb 29, 2020 at 06:11:20PM -0500, Arvind Sankar wrote:
> > This currently leaks kernel physical addresses into userspace.
> >
> > Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
> > ---
> > arch/x86/mm/init.c | 2 --
> > 1 file changed, 2 deletions(-)
> >
> > diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c
> > index e7bb483557c9..dc4711f09cdc 100644
> > --- a/arch/x86/mm/init.c
> > +++ b/arch/x86/mm/init.c
> > @@ -121,8 +121,6 @@ __ref void *alloc_low_pages(unsigned int num)
> > } else {
> > pfn = pgt_buf_end;
> > pgt_buf_end += num;
> > - printk(KERN_DEBUG "BRK [%#010lx, %#010lx] PGTABLE\n",
> > - pfn << PAGE_SHIFT, (pgt_buf_end << PAGE_SHIFT) - 1);
> > }
> >
> > for (i = 0; i < num; i++) {
> > --
> > 2.24.1
> >
>
> Ping.
>
> https://lore.kernel.org/lkml/20200229231120.1147527-1-nivedita@alum.mit.edu/
If this output is at all valuable,
perhaps emit them as hashed pointers?
Maybe:
---
arch/x86/mm/init.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c
index 1bba16c5742b..44f0d6592c7e 100644
--- a/arch/x86/mm/init.c
+++ b/arch/x86/mm/init.c
@@ -121,8 +121,9 @@ __ref void *alloc_low_pages(unsigned int num)
} else {
pfn = pgt_buf_end;
pgt_buf_end += num;
- printk(KERN_DEBUG "BRK [%#010lx, %#010lx] PGTABLE\n",
- pfn << PAGE_SHIFT, (pgt_buf_end << PAGE_SHIFT) - 1);
+ printk(KERN_DEBUG "BRK [0x%8p, 0x%8p] PGTABLE\n",
+ (void *)(pfn << PAGE_SHIFT),
+ (void *)((pgt_buf_end << PAGE_SHIFT) - 1));
}
for (i = 0; i < num; i++) {
^ permalink raw reply related [flat|nested] 8+ messages in thread
* Re: [PATCH] x86/mm/init: Stop printing pgt_buf addresses
@ 2020-05-23 2:57 ` Joe Perches
0 siblings, 0 replies; 8+ messages in thread
From: Joe Perches @ 2020-05-23 2:57 UTC (permalink / raw)
To: Arvind Sankar
Cc: Tobin C . Harding, Tycho Andersen, kernel-hardening, Kees Cook,
Dave Hansen, Andy Lutomirski, Peter Zijlstra, x86, linux-kernel
On Fri, 2020-05-22 at 21:51 -0400, Arvind Sankar wrote:
> On Sat, Feb 29, 2020 at 06:11:20PM -0500, Arvind Sankar wrote:
> > This currently leaks kernel physical addresses into userspace.
> >
> > Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
> > ---
> > arch/x86/mm/init.c | 2 --
> > 1 file changed, 2 deletions(-)
> >
> > diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c
> > index e7bb483557c9..dc4711f09cdc 100644
> > --- a/arch/x86/mm/init.c
> > +++ b/arch/x86/mm/init.c
> > @@ -121,8 +121,6 @@ __ref void *alloc_low_pages(unsigned int num)
> > } else {
> > pfn = pgt_buf_end;
> > pgt_buf_end += num;
> > - printk(KERN_DEBUG "BRK [%#010lx, %#010lx] PGTABLE\n",
> > - pfn << PAGE_SHIFT, (pgt_buf_end << PAGE_SHIFT) - 1);
> > }
> >
> > for (i = 0; i < num; i++) {
> > --
> > 2.24.1
> >
>
> Ping.
>
> https://lore.kernel.org/lkml/20200229231120.1147527-1-nivedita@alum.mit.edu/
If this output is at all valuable,
perhaps emit them as hashed pointers?
Maybe:
---
arch/x86/mm/init.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c
index 1bba16c5742b..44f0d6592c7e 100644
--- a/arch/x86/mm/init.c
+++ b/arch/x86/mm/init.c
@@ -121,8 +121,9 @@ __ref void *alloc_low_pages(unsigned int num)
} else {
pfn = pgt_buf_end;
pgt_buf_end += num;
- printk(KERN_DEBUG "BRK [%#010lx, %#010lx] PGTABLE\n",
- pfn << PAGE_SHIFT, (pgt_buf_end << PAGE_SHIFT) - 1);
+ printk(KERN_DEBUG "BRK [0x%8p, 0x%8p] PGTABLE\n",
+ (void *)(pfn << PAGE_SHIFT),
+ (void *)((pgt_buf_end << PAGE_SHIFT) - 1));
}
for (i = 0; i < num; i++) {
^ permalink raw reply related [flat|nested] 8+ messages in thread
* [tip: x86/cleanups] x86/mm: Stop printing BRK addresses
2020-02-29 23:11 [PATCH] x86/mm/init: Stop printing pgt_buf addresses Arvind Sankar
` (2 preceding siblings ...)
2020-05-23 1:51 ` Arvind Sankar
@ 2020-05-23 7:41 ` tip-bot2 for Arvind Sankar
3 siblings, 0 replies; 8+ messages in thread
From: tip-bot2 for Arvind Sankar @ 2020-05-23 7:41 UTC (permalink / raw)
To: linux-tip-commits
Cc: Arvind Sankar, Borislav Petkov, Kees Cook, Dave Hansen, x86, LKML
The following commit has been merged into the x86/cleanups branch of tip:
Commit-ID: 67d631b7c05eff955ccff4139327f0f92a5117e5
Gitweb: https://git.kernel.org/tip/67d631b7c05eff955ccff4139327f0f92a5117e5
Author: Arvind Sankar <nivedita@alum.mit.edu>
AuthorDate: Sat, 29 Feb 2020 18:11:20 -05:00
Committer: Borislav Petkov <bp@suse.de>
CommitterDate: Sat, 23 May 2020 09:34:18 +02:00
x86/mm: Stop printing BRK addresses
This currently leaks kernel physical addresses into userspace.
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Kees Cook <keescook@chromium.org>
Acked-by: Dave Hansen <dave.hansen@intel.com>
Link: https://lkml.kernel.org/r/20200229231120.1147527-1-nivedita@alum.mit.edu
---
arch/x86/mm/init.c | 2 --
1 file changed, 2 deletions(-)
diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c
index 1bba16c..a573a3e 100644
--- a/arch/x86/mm/init.c
+++ b/arch/x86/mm/init.c
@@ -121,8 +121,6 @@ __ref void *alloc_low_pages(unsigned int num)
} else {
pfn = pgt_buf_end;
pgt_buf_end += num;
- printk(KERN_DEBUG "BRK [%#010lx, %#010lx] PGTABLE\n",
- pfn << PAGE_SHIFT, (pgt_buf_end << PAGE_SHIFT) - 1);
}
for (i = 0; i < num; i++) {
^ permalink raw reply related [flat|nested] 8+ messages in thread
end of thread, other threads:[~2020-05-23 7:41 UTC | newest]
Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-02-29 23:11 [PATCH] x86/mm/init: Stop printing pgt_buf addresses Arvind Sankar
2020-02-29 23:23 ` Kees Cook
2020-04-09 22:19 ` Arvind Sankar
2020-04-09 22:35 ` Dave Hansen
2020-05-23 1:51 ` Arvind Sankar
2020-05-23 2:57 ` Joe Perches
2020-05-23 2:57 ` Joe Perches
2020-05-23 7:41 ` [tip: x86/cleanups] x86/mm: Stop printing BRK addresses tip-bot2 for Arvind Sankar
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