Searched hist:af6fc858a35b90e89ea7a7ee58e66628c55c776b (Results 1 – 4 of 4) sorted by relevance
/linux/drivers/xen/xen-pciback/ |
H A D | conf_space.h | diff af6fc858a35b90e89ea7a7ee58e66628c55c776b Wed Mar 11 14:51:17 CET 2015 Jan Beulich <JBeulich@suse.com> xen-pciback: limit guest control of command register
Otherwise the guest can abuse that control to cause e.g. PCIe Unsupported Request responses by disabling memory and/or I/O decoding and subsequently causing (CPU side) accesses to the respective address ranges, which (depending on system configuration) may be fatal to the host.
Note that to alter any of the bits collected together as PCI_COMMAND_GUEST permissive mode is now required to be enabled globally or on the specific device.
This is CVE-2015-2150 / XSA-120.
Signed-off-by: Jan Beulich <jbeulich@suse.com> Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: <stable@vger.kernel.org> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
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H A D | conf_space_header.c | diff af6fc858a35b90e89ea7a7ee58e66628c55c776b Wed Mar 11 14:51:17 CET 2015 Jan Beulich <JBeulich@suse.com> xen-pciback: limit guest control of command register
Otherwise the guest can abuse that control to cause e.g. PCIe Unsupported Request responses by disabling memory and/or I/O decoding and subsequently causing (CPU side) accesses to the respective address ranges, which (depending on system configuration) may be fatal to the host.
Note that to alter any of the bits collected together as PCI_COMMAND_GUEST permissive mode is now required to be enabled globally or on the specific device.
This is CVE-2015-2150 / XSA-120.
Signed-off-by: Jan Beulich <jbeulich@suse.com> Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: <stable@vger.kernel.org> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
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H A D | conf_space.c | diff af6fc858a35b90e89ea7a7ee58e66628c55c776b Wed Mar 11 14:51:17 CET 2015 Jan Beulich <JBeulich@suse.com> xen-pciback: limit guest control of command register
Otherwise the guest can abuse that control to cause e.g. PCIe Unsupported Request responses by disabling memory and/or I/O decoding and subsequently causing (CPU side) accesses to the respective address ranges, which (depending on system configuration) may be fatal to the host.
Note that to alter any of the bits collected together as PCI_COMMAND_GUEST permissive mode is now required to be enabled globally or on the specific device.
This is CVE-2015-2150 / XSA-120.
Signed-off-by: Jan Beulich <jbeulich@suse.com> Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: <stable@vger.kernel.org> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
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H A D | pciback_ops.c | diff 7681f31ec9cdacab4fd10570be924f2cef6669ba Thu Feb 14 00:21:31 CET 2019 Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> xen/pciback: Don't disable PCI_COMMAND on PCI device reset.
There is no need for this at all. Worst it means that if the guest tries to write to BARs it could lead (on certain platforms) to PCI SERR errors.
Please note that with af6fc858a35b90e89ea7a7ee58e66628c55c776b "xen-pciback: limit guest control of command register" a guest is still allowed to enable those control bits (safely), but is not allowed to disable them and that therefore a well behaved frontend which enables things before using them will still function correctly.
This is done via an write to the configuration register 0x4 which triggers on the backend side: command_write \- pci_enable_device \- pci_enable_device_flags \- do_pci_enable_device \- pcibios_enable_device \-pci_enable_resourcess [which enables the PCI_COMMAND_MEMORY|PCI_COMMAND_IO]
However guests (and drivers) which don't do this could cause problems, including the security issues which XSA-120 sought to address.
Reported-by: Jan Beulich <jbeulich@suse.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Reviewed-by: Prarit Bhargava <prarit@redhat.com> Signed-off-by: Juergen Gross <jgross@suse.com>
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