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| author | Vitaly Kuznetsov <vkuznets@redhat.com> | 2016-03-15 09:20:33 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2016-03-15 11:08:26 +0100 |
| commit | 743146db071c4a828159211a295d12ff4f61752f (patch) | |
| tree | 4a59e606c0e7fe94c8a11ae53b0c934e91cc72f1 | |
| parent | e23604edac2a7be6a8808a5d13fac6b9df4eb9a8 (diff) | |
| download | linux-743146db071c4a828159211a295d12ff4f61752f.tar.gz linux-743146db071c4a828159211a295d12ff4f61752f.tar.bz2 linux-743146db071c4a828159211a295d12ff4f61752f.zip | |
x86/video: Don't assume all FB devices are PCI devices
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.
While on it, clean up the function.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Bjorn Helgaas <helgaas@kernel.org>
Cc: Cathy Avery <cavery@redhat.com>
Cc: K. Y. Srinivasan <kys@microsoft.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1458030033-10122-1-git-send-email-vkuznets@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
| -rw-r--r-- | arch/x86/video/fbdev.c | 18 |
1 files changed, 8 insertions, 10 deletions
diff --git a/arch/x86/video/fbdev.c b/arch/x86/video/fbdev.c index d5644bbe8cba..9fd24846d094 100644 --- a/arch/x86/video/fbdev.c +++ b/arch/x86/video/fbdev.c @@ -14,26 +14,24 @@ int fb_is_primary_device(struct fb_info *info) { struct device *device = info->device; - struct pci_dev *pci_dev = NULL; struct pci_dev *default_device = vga_default_device(); - struct resource *res = NULL; + struct pci_dev *pci_dev; + struct resource *res; - 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; - else - return 0; + return 0; } - res = &pci_dev->resource[PCI_ROM_RESOURCE]; + res = pci_dev->resource + PCI_ROM_RESOURCE; - if (res && res->flags & IORESOURCE_ROM_SHADOW) + if (res->flags & IORESOURCE_ROM_SHADOW) return 1; return 0; |