* [PATCH v2] x86: don't assume all fb devices are PCI devices
@ 2016-03-14 14:42 Vitaly Kuznetsov
2016-03-14 15:28 ` Bjorn Helgaas
0 siblings, 1 reply; 4+ messages in thread
From: Vitaly Kuznetsov @ 2016-03-14 14:42 UTC (permalink / raw)
To: x86
Cc: linux-kernel, Thomas Gleixner, Ingo Molnar, H. Peter Anvin,
Cathy Avery, K. Y. Srinivasan, Bjorn Helgaas
When booting Hyper-V Generation 2 guests KASAN reports the following
out-of-bounds access:
BUG: KASAN: slab-out-of-bounds in fb_is_primary_device+0x58/0x70 at addr
ffff880079cf0eb0
Read of size 8 by task swapper/0/1
...
[<ffffffff81581308>] dump_stack+0x63/0x8b
[<ffffffff812e1f99>] print_trailer+0xf9/0x150
[<ffffffff812e7344>] object_err+0x34/0x40
[<ffffffff812e9630>] kasan_report_error+0x230/0x550
[<ffffffff812e9ee8>] kasan_report+0x58/0x60
[<ffffffff812e4500>] ? ___slab_alloc+0x80/0x490
[<ffffffff81878a28>] ? fb_is_primary_device+0x58/0x70
[<ffffffff812e87cd>] __asan_load8+0x5d/0x70
[<ffffffff81878a28>] fb_is_primary_device+0x58/0x70
[<ffffffff8162357a>] register_framebuffer+0xda/0x5b0
[<ffffffff816234a0>] ? remove_conflicting_framebuffers+0x50/0x50
...
The issue is caused by the to_pci_dev() call with no check that the given
info->device is in fact a pci device and some fb devices (Hyper-V FB, EFI
FB,...) are not.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
---
Changes since v1: use dev_is_pci() instead of full scan [Bjorn Helgaas].
---
arch/x86/video/fbdev.c | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)
diff --git a/arch/x86/video/fbdev.c b/arch/x86/video/fbdev.c
index d5644bb..9f2fe63 100644
--- a/arch/x86/video/fbdev.c
+++ b/arch/x86/video/fbdev.c
@@ -18,12 +18,11 @@ int fb_is_primary_device(struct fb_info *info)
struct pci_dev *default_device = vga_default_device();
struct resource *res = NULL;
- if (device)
- pci_dev = to_pci_dev(device);
-
- if (!pci_dev)
+ if (!device || !dev_is_pci(device))
return 0;
+ pci_dev = to_pci_dev(device);
+
if (default_device) {
if (pci_dev == default_device)
return 1;
--
2.5.0
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH v2] x86: don't assume all fb devices are PCI devices
2016-03-14 14:42 [PATCH v2] x86: don't assume all fb devices are PCI devices Vitaly Kuznetsov
@ 2016-03-14 15:28 ` Bjorn Helgaas
2016-03-14 16:33 ` Ingo Molnar
0 siblings, 1 reply; 4+ messages in thread
From: Bjorn Helgaas @ 2016-03-14 15:28 UTC (permalink / raw)
To: Vitaly Kuznetsov
Cc: x86, linux-kernel, Thomas Gleixner, Ingo Molnar, H. Peter Anvin,
Cathy Avery, K. Y. Srinivasan
On Mon, Mar 14, 2016 at 03:42:57PM +0100, Vitaly Kuznetsov wrote:
> When booting Hyper-V Generation 2 guests KASAN reports the following
> out-of-bounds access:
>
> BUG: KASAN: slab-out-of-bounds in fb_is_primary_device+0x58/0x70 at addr
> ffff880079cf0eb0
> Read of size 8 by task swapper/0/1
> ...
> [<ffffffff81581308>] dump_stack+0x63/0x8b
> [<ffffffff812e1f99>] print_trailer+0xf9/0x150
> [<ffffffff812e7344>] object_err+0x34/0x40
> [<ffffffff812e9630>] kasan_report_error+0x230/0x550
> [<ffffffff812e9ee8>] kasan_report+0x58/0x60
> [<ffffffff812e4500>] ? ___slab_alloc+0x80/0x490
> [<ffffffff81878a28>] ? fb_is_primary_device+0x58/0x70
> [<ffffffff812e87cd>] __asan_load8+0x5d/0x70
> [<ffffffff81878a28>] fb_is_primary_device+0x58/0x70
> [<ffffffff8162357a>] register_framebuffer+0xda/0x5b0
> [<ffffffff816234a0>] ? remove_conflicting_framebuffers+0x50/0x50
> ...
>
> The issue is caused by the to_pci_dev() call with no check that the given
> info->device is in fact a pci device and some fb devices (Hyper-V FB, EFI
> FB,...) are not.
>
> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
> ---
> Changes since v1: use dev_is_pci() instead of full scan [Bjorn Helgaas].
> ---
> arch/x86/video/fbdev.c | 7 +++----
> 1 file changed, 3 insertions(+), 4 deletions(-)
>
> diff --git a/arch/x86/video/fbdev.c b/arch/x86/video/fbdev.c
> index d5644bb..9f2fe63 100644
> --- a/arch/x86/video/fbdev.c
> +++ b/arch/x86/video/fbdev.c
> @@ -18,12 +18,11 @@ int fb_is_primary_device(struct fb_info *info)
> struct pci_dev *default_device = vga_default_device();
> struct resource *res = NULL;
The initializations of "pci_dev" and "res" to NULL are now
unnecessary.
>
> - if (device)
> - pci_dev = to_pci_dev(device);
> -
> - if (!pci_dev)
> + if (!device || !dev_is_pci(device))
> return 0;
>
> + pci_dev = to_pci_dev(device);
> +
> if (default_device) {
> if (pci_dev == default_device)
> return 1;
The test for non-NULL "res" below is superfluous because we know
"pci_dev" is non-NULL:
res = &pci_dev->resource[PCI_ROM_RESOURCE];
if (res && res->flags & IORESOURCE_ROM_SHADOW)
I think your patch is functionally correct, so it's up to you and the
x86 guys whether you want to do these additional cleanups.
Bjorn
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH v2] x86: don't assume all fb devices are PCI devices
2016-03-14 15:28 ` Bjorn Helgaas
@ 2016-03-14 16:33 ` Ingo Molnar
2016-03-14 16:48 ` Vitaly Kuznetsov
0 siblings, 1 reply; 4+ messages in thread
From: Ingo Molnar @ 2016-03-14 16:33 UTC (permalink / raw)
To: Bjorn Helgaas
Cc: Vitaly Kuznetsov, x86, linux-kernel, Thomas Gleixner,
Ingo Molnar, H. Peter Anvin, Cathy Avery, K. Y. Srinivasan
* Bjorn Helgaas <helgaas@kernel.org> wrote:
> On Mon, Mar 14, 2016 at 03:42:57PM +0100, Vitaly Kuznetsov wrote:
> > When booting Hyper-V Generation 2 guests KASAN reports the following
> > out-of-bounds access:
> >
> > BUG: KASAN: slab-out-of-bounds in fb_is_primary_device+0x58/0x70 at addr
> > ffff880079cf0eb0
> > Read of size 8 by task swapper/0/1
> > ...
> > [<ffffffff81581308>] dump_stack+0x63/0x8b
> > [<ffffffff812e1f99>] print_trailer+0xf9/0x150
> > [<ffffffff812e7344>] object_err+0x34/0x40
> > [<ffffffff812e9630>] kasan_report_error+0x230/0x550
> > [<ffffffff812e9ee8>] kasan_report+0x58/0x60
> > [<ffffffff812e4500>] ? ___slab_alloc+0x80/0x490
> > [<ffffffff81878a28>] ? fb_is_primary_device+0x58/0x70
> > [<ffffffff812e87cd>] __asan_load8+0x5d/0x70
> > [<ffffffff81878a28>] fb_is_primary_device+0x58/0x70
> > [<ffffffff8162357a>] register_framebuffer+0xda/0x5b0
> > [<ffffffff816234a0>] ? remove_conflicting_framebuffers+0x50/0x50
> > ...
> >
> > The issue is caused by the to_pci_dev() call with no check that the given
> > info->device is in fact a pci device and some fb devices (Hyper-V FB, EFI
> > FB,...) are not.
> >
> > Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
>
> Acked-by: Bjorn Helgaas <bhelgaas@google.com>
>
> > ---
> > Changes since v1: use dev_is_pci() instead of full scan [Bjorn Helgaas].
> > ---
> > arch/x86/video/fbdev.c | 7 +++----
> > 1 file changed, 3 insertions(+), 4 deletions(-)
> >
> > diff --git a/arch/x86/video/fbdev.c b/arch/x86/video/fbdev.c
> > index d5644bb..9f2fe63 100644
> > --- a/arch/x86/video/fbdev.c
> > +++ b/arch/x86/video/fbdev.c
> > @@ -18,12 +18,11 @@ int fb_is_primary_device(struct fb_info *info)
> > struct pci_dev *default_device = vga_default_device();
> > struct resource *res = NULL;
>
> The initializations of "pci_dev" and "res" to NULL are now
> unnecessary.
>
> >
> > - if (device)
> > - pci_dev = to_pci_dev(device);
> > -
> > - if (!pci_dev)
> > + if (!device || !dev_is_pci(device))
> > return 0;
> >
> > + pci_dev = to_pci_dev(device);
> > +
> > if (default_device) {
> > if (pci_dev == default_device)
> > return 1;
>
> The test for non-NULL "res" below is superfluous because we know
> "pci_dev" is non-NULL:
>
> res = &pci_dev->resource[PCI_ROM_RESOURCE];
> if (res && res->flags & IORESOURCE_ROM_SHADOW)
>
> I think your patch is functionally correct, so it's up to you and the
> x86 guys whether you want to do these additional cleanups.
I'd like to see those cleanups as well, no point in delaying them, right?
btw., I'd suggest writing this:
> res = &pci_dev->resource[PCI_ROM_RESOURCE];
as:
> res = pci_dev->resource + PCI_ROM_RESOURCE;
Thanks,
Ingo
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH v2] x86: don't assume all fb devices are PCI devices
2016-03-14 16:33 ` Ingo Molnar
@ 2016-03-14 16:48 ` Vitaly Kuznetsov
0 siblings, 0 replies; 4+ messages in thread
From: Vitaly Kuznetsov @ 2016-03-14 16:48 UTC (permalink / raw)
To: Ingo Molnar
Cc: Bjorn Helgaas, x86, linux-kernel, Thomas Gleixner, Ingo Molnar,
H. Peter Anvin, Cathy Avery, K. Y. Srinivasan
Ingo Molnar <mingo@kernel.org> writes:
> * Bjorn Helgaas <helgaas@kernel.org> wrote:
>
>> On Mon, Mar 14, 2016 at 03:42:57PM +0100, Vitaly Kuznetsov wrote:
>> > When booting Hyper-V Generation 2 guests KASAN reports the following
>> > out-of-bounds access:
>> >
>> > BUG: KASAN: slab-out-of-bounds in fb_is_primary_device+0x58/0x70 at addr
>> > ffff880079cf0eb0
>> > Read of size 8 by task swapper/0/1
>> > ...
>> > [<ffffffff81581308>] dump_stack+0x63/0x8b
>> > [<ffffffff812e1f99>] print_trailer+0xf9/0x150
>> > [<ffffffff812e7344>] object_err+0x34/0x40
>> > [<ffffffff812e9630>] kasan_report_error+0x230/0x550
>> > [<ffffffff812e9ee8>] kasan_report+0x58/0x60
>> > [<ffffffff812e4500>] ? ___slab_alloc+0x80/0x490
>> > [<ffffffff81878a28>] ? fb_is_primary_device+0x58/0x70
>> > [<ffffffff812e87cd>] __asan_load8+0x5d/0x70
>> > [<ffffffff81878a28>] fb_is_primary_device+0x58/0x70
>> > [<ffffffff8162357a>] register_framebuffer+0xda/0x5b0
>> > [<ffffffff816234a0>] ? remove_conflicting_framebuffers+0x50/0x50
>> > ...
>> >
>> > The issue is caused by the to_pci_dev() call with no check that the given
>> > info->device is in fact a pci device and some fb devices (Hyper-V FB, EFI
>> > FB,...) are not.
>> >
>> > Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
>>
>> Acked-by: Bjorn Helgaas <bhelgaas@google.com>
>>
>> > ---
>> > Changes since v1: use dev_is_pci() instead of full scan [Bjorn Helgaas].
>> > ---
>> > arch/x86/video/fbdev.c | 7 +++----
>> > 1 file changed, 3 insertions(+), 4 deletions(-)
>> >
>> > diff --git a/arch/x86/video/fbdev.c b/arch/x86/video/fbdev.c
>> > index d5644bb..9f2fe63 100644
>> > --- a/arch/x86/video/fbdev.c
>> > +++ b/arch/x86/video/fbdev.c
>> > @@ -18,12 +18,11 @@ int fb_is_primary_device(struct fb_info *info)
>> > struct pci_dev *default_device = vga_default_device();
>> > struct resource *res = NULL;
>>
>> The initializations of "pci_dev" and "res" to NULL are now
>> unnecessary.
>>
>> >
>> > - if (device)
>> > - pci_dev = to_pci_dev(device);
>> > -
>> > - if (!pci_dev)
>> > + if (!device || !dev_is_pci(device))
>> > return 0;
>> >
>> > + pci_dev = to_pci_dev(device);
>> > +
>> > if (default_device) {
>> > if (pci_dev == default_device)
>> > return 1;
>>
>> The test for non-NULL "res" below is superfluous because we know
>> "pci_dev" is non-NULL:
>>
>> res = &pci_dev->resource[PCI_ROM_RESOURCE];
>> if (res && res->flags & IORESOURCE_ROM_SHADOW)
>>
>> I think your patch is functionally correct, so it's up to you and the
>> x86 guys whether you want to do these additional cleanups.
>
> I'd like to see those cleanups as well, no point in delaying them, right?
>
Sure, will do v3!
> btw., I'd suggest writing this:
>
>> res = &pci_dev->resource[PCI_ROM_RESOURCE];
>
> as:
>
>> res = pci_dev->resource + PCI_ROM_RESOURCE;
>
--
Vitaly
^ permalink raw reply [flat|nested] 4+ messages in thread
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2016-03-14 14:42 [PATCH v2] x86: don't assume all fb devices are PCI devices Vitaly Kuznetsov
2016-03-14 15:28 ` Bjorn Helgaas
2016-03-14 16:33 ` Ingo Molnar
2016-03-14 16:48 ` Vitaly Kuznetsov
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