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Groups > linux.kernel > #1355952 > unrolled thread
| Started by | Vitaly Kuznetsov <vkuznets@redhat.com> |
|---|---|
| First post | 2016-03-11 15:40 +0100 |
| Last post | 2016-03-14 11:00 +0100 |
| Articles | 4 — 3 participants |
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[PATCH] x86: don't assume all fb devices are PCI devices Vitaly Kuznetsov <vkuznets@redhat.com> - 2016-03-11 15:40 +0100
Re: [PATCH] x86: don't assume all fb devices are PCI devices Ingo Molnar <mingo@kernel.org> - 2016-03-12 16:50 +0100
Re: [PATCH] x86: don't assume all fb devices are PCI devices Bjorn Helgaas <helgaas@kernel.org> - 2016-03-12 22:00 +0100
Re: [PATCH] x86: don't assume all fb devices are PCI devices Vitaly Kuznetsov <vkuznets@redhat.com> - 2016-03-14 11:00 +0100
| From | Vitaly Kuznetsov <vkuznets@redhat.com> |
|---|---|
| Date | 2016-03-11 15:40 +0100 |
| Subject | [PATCH] x86: don't assume all fb devices are PCI devices |
| Message-ID | <rbwop-7y9-13@gated-at.bofh.it> |
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. fb_is_primary_device() is not on any performance critical
path, replace to_pci_dev() with raw scan.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
---
arch/x86/video/fbdev.c | 12 +++++++++---
1 file changed, 9 insertions(+), 3 deletions(-)
diff --git a/arch/x86/video/fbdev.c b/arch/x86/video/fbdev.c
index d5644bb..f309d6c 100644
--- a/arch/x86/video/fbdev.c
+++ b/arch/x86/video/fbdev.c
@@ -14,12 +14,18 @@
int fb_is_primary_device(struct fb_info *info)
{
struct device *device = info->device;
- struct pci_dev *pci_dev = NULL;
+ struct pci_dev *dev = NULL, *pci_dev = NULL;
struct pci_dev *default_device = vga_default_device();
struct resource *res = NULL;
- if (device)
- pci_dev = to_pci_dev(device);
+ /*
+ * We're not sure info->device is a pci device, do full scan instead
+ * of to_pci_dev().
+ */
+ for_each_pci_dev(dev) {
+ if (&dev->dev == device)
+ pci_dev = dev;
+ }
if (!pci_dev)
return 0;
--
2.5.0
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| From | Ingo Molnar <mingo@kernel.org> |
|---|---|
| Date | 2016-03-12 16:50 +0100 |
| Message-ID | <rbTXI-8jU-7@gated-at.bofh.it> |
| In reply to | #1355952 |
So I'd love to have an ACK from Bjorn. (Full mail quoted below)
Thanks,
Ingo
* Vitaly Kuznetsov <vkuznets@redhat.com> 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. fb_is_primary_device() is not on any performance critical
> path, replace to_pci_dev() with raw scan.
>
> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
> ---
> arch/x86/video/fbdev.c | 12 +++++++++---
> 1 file changed, 9 insertions(+), 3 deletions(-)
>
> diff --git a/arch/x86/video/fbdev.c b/arch/x86/video/fbdev.c
> index d5644bb..f309d6c 100644
> --- a/arch/x86/video/fbdev.c
> +++ b/arch/x86/video/fbdev.c
> @@ -14,12 +14,18 @@
> int fb_is_primary_device(struct fb_info *info)
> {
> struct device *device = info->device;
> - struct pci_dev *pci_dev = NULL;
> + struct pci_dev *dev = NULL, *pci_dev = NULL;
> struct pci_dev *default_device = vga_default_device();
> struct resource *res = NULL;
>
> - if (device)
> - pci_dev = to_pci_dev(device);
> + /*
> + * We're not sure info->device is a pci device, do full scan instead
> + * of to_pci_dev().
> + */
> + for_each_pci_dev(dev) {
> + if (&dev->dev == device)
> + pci_dev = dev;
> + }
>
> if (!pci_dev)
> return 0;
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| From | Bjorn Helgaas <helgaas@kernel.org> |
|---|---|
| Date | 2016-03-12 22:00 +0100 |
| Message-ID | <rbYNI-3qA-9@gated-at.bofh.it> |
| In reply to | #1355952 |
On Fri, Mar 11, 2016 at 03:39:18PM +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. fb_is_primary_device() is not on any performance critical
> path, replace to_pci_dev() with raw scan.
>
> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
> ---
> arch/x86/video/fbdev.c | 12 +++++++++---
> 1 file changed, 9 insertions(+), 3 deletions(-)
>
> diff --git a/arch/x86/video/fbdev.c b/arch/x86/video/fbdev.c
> index d5644bb..f309d6c 100644
> --- a/arch/x86/video/fbdev.c
> +++ b/arch/x86/video/fbdev.c
> @@ -14,12 +14,18 @@
> int fb_is_primary_device(struct fb_info *info)
> {
> struct device *device = info->device;
> - struct pci_dev *pci_dev = NULL;
> + struct pci_dev *dev = NULL, *pci_dev = NULL;
> struct pci_dev *default_device = vga_default_device();
> struct resource *res = NULL;
>
> - if (device)
> - pci_dev = to_pci_dev(device);
> + /*
> + * We're not sure info->device is a pci device, do full scan instead
> + * of to_pci_dev().
> + */
> + for_each_pci_dev(dev) {
> + if (&dev->dev == device)
> + pci_dev = dev;
> + }
> if (!pci_dev)
> return 0;
I think dev_is_pci() is a better solution:
if (!device || !dev_is_pci(device))
return 0;
pci_dev = to_pci_dev(device);
if (vga_default_device()) {
if (vga_default_device() == pci_dev)
return 1;
return 0;
}
res = &pci_dev->resource[PCI_ROM_RESOURCE];
if (res->flags & IORESOURCE_ROM_SHADOW)
return 1;
return 0;
This says a non-PCI device cannot be the primary device. I don't know
framebuffers, so I don't know if that's what you really want, but I
guess it's what the original code says.
Bjorn
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| From | Vitaly Kuznetsov <vkuznets@redhat.com> |
|---|---|
| Date | 2016-03-14 11:00 +0100 |
| Message-ID | <rcxs5-22b-7@gated-at.bofh.it> |
| In reply to | #1356537 |
Bjorn Helgaas <helgaas@kernel.org> writes:
> On Fri, Mar 11, 2016 at 03:39:18PM +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. fb_is_primary_device() is not on any performance critical
>> path, replace to_pci_dev() with raw scan.
>>
>> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
>> ---
>> arch/x86/video/fbdev.c | 12 +++++++++---
>> 1 file changed, 9 insertions(+), 3 deletions(-)
>>
>> diff --git a/arch/x86/video/fbdev.c b/arch/x86/video/fbdev.c
>> index d5644bb..f309d6c 100644
>> --- a/arch/x86/video/fbdev.c
>> +++ b/arch/x86/video/fbdev.c
>> @@ -14,12 +14,18 @@
>> int fb_is_primary_device(struct fb_info *info)
>> {
>> struct device *device = info->device;
>> - struct pci_dev *pci_dev = NULL;
>> + struct pci_dev *dev = NULL, *pci_dev = NULL;
>> struct pci_dev *default_device = vga_default_device();
>> struct resource *res = NULL;
>>
>> - if (device)
>> - pci_dev = to_pci_dev(device);
>> + /*
>> + * We're not sure info->device is a pci device, do full scan instead
>> + * of to_pci_dev().
>> + */
>> + for_each_pci_dev(dev) {
>> + if (&dev->dev == device)
>> + pci_dev = dev;
>> + }
>> if (!pci_dev)
>> return 0;
>
> I think dev_is_pci() is a better solution:
>
> if (!device || !dev_is_pci(device))
> return 0;
Sure, will do v2.
>
> pci_dev = to_pci_dev(device);
> if (vga_default_device()) {
> if (vga_default_device() == pci_dev)
> return 1;
> return 0;
> }
>
> res = &pci_dev->resource[PCI_ROM_RESOURCE];
> if (res->flags & IORESOURCE_ROM_SHADOW)
> return 1;
>
> return 0;
>
> This says a non-PCI device cannot be the primary device. I don't know
> framebuffers, so I don't know if that's what you really want, but I
> guess it's what the original code says.
Yes, the original code is for pci devices only and I didn't plan to
change that, my intention is to prevent out-of-bounds access.
>
> Bjorn
--
Vitaly
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