* [Qemu-devel] [PULL] VirtFS Proxy FS driver changes
@ 2012-01-04 16:28 Aneesh Kumar K.V
2012-01-09 14:52 ` Anthony Liguori
0 siblings, 1 reply; 2+ messages in thread
From: Aneesh Kumar K.V @ 2012-01-04 16:28 UTC (permalink / raw)
To: Anthony Liguori, QEMU Developers, M. Mohan Kumar
The following changes since commit f3c6a169a39d188e98c17a0a0ebfa7f85e5aafdd:
Merge remote-tracking branch 'qemu-kvm/memory/page_desc' into staging (2012-01-03 14:39:05 -0600)
are available in the git repository at:
git://github.com/kvaneesh/QEMU.git for-upstream
Also available at signed tag virtfs-proxy-support
for you to fetch changes up to 84a87cc4cc77f9e6829e20726f00646afe12deed:
hw/9pfs: Add support to use named socket for proxy FS (2012-01-04 21:23:55 +0530)
----------------------------------------------------------------
Pass-through security model in QEMU 9p server needs root privilege to do
few file operations (like chown, chmod to any mode/uid:gid). There are two
issues in pass-through security model
1) TOCTTOU vulnerability: Following symbolic links in the server could
provide access to files beyond 9p export path.
2) Running QEMU with root privilege could be a security issue.
To overcome above issues, following approach is used: A new filesytem
type 'proxy' is introduced. Proxy FS uses chroot + socket combination
for securing the vulnerability known with following symbolic links.
Intention of adding a new filesystem type is to allow qemu to run
in non-root mode, but doing privileged operations using socket IO.
Proxy helper(a stand alone binary part of qemu) is invoked with
root privileges. Proxy helper chroots into 9p export path and creates
a socket pair or a named socket based on the command line parameter.
Qemu and proxy helper communicate using this socket. QEMU proxy fs
driver sends filesystem request to proxy helper and receives the
response from it.
Proxy helper is designed so that it can drop the root privilege but
retaining capbilities that are needed for doing filesystem operations
(like CAP_DAC_OVERRIDE, CAP_FOWNER etc)
----------------------------------------------------------------
Aneesh Kumar K.V (1):
hw/9pfs: Move opt validation to FsDriver callback
M. Mohan Kumar (13):
hw/9pfs: Move pdu_marshal/unmarshal code to a seperate file
hw/9pfs: Add validation to {un}marshal code
hw/9pfs: Add new proxy filesystem driver
hw/9pfs: File system helper process for qemu 9p proxy FS
hw/9pfs: Open and create files
hw/9pfs: Create other filesystem objects
hw/9pfs: Add stat/readlink/statfs for proxy FS
hw/9pfs: File ownership and others
hw/9pfs: xattr interfaces in proxy filesystem driver
hw/9pfs: Proxy getversion
hw/9pfs: Documentation changes related to proxy fs
hw/9pfs: man page for proxy helper
hw/9pfs: Add support to use named socket for proxy FS
Makefile | 15 +-
Makefile.objs | 3 +-
configure | 19 +
fsdev/file-op-9p.h | 17 +-
fsdev/qemu-fsdev.c | 45 +--
fsdev/qemu-fsdev.h | 11 +-
fsdev/virtfs-proxy-helper.c | 1120 +++++++++++++++++++++++++++++++++++++
fsdev/virtfs-proxy-helper.texi | 63 +++
fsdev/virtio-9p-marshal.c | 323 +++++++++++
fsdev/virtio-9p-marshal.h | 90 +++
hw/9pfs/virtio-9p-device.c | 13 +-
hw/9pfs/virtio-9p-handle.c | 20 +
hw/9pfs/virtio-9p-local.c | 34 ++
hw/9pfs/virtio-9p-proxy.c | 1210 ++++++++++++++++++++++++++++++++++++++++
hw/9pfs/virtio-9p-proxy.h | 95 ++++
hw/9pfs/virtio-9p.c | 704 +++++++++++------------
hw/9pfs/virtio-9p.h | 83 +---
qemu-config.c | 13 +
qemu-options.hx | 32 +-
vl.c | 18 +-
20 files changed, 3414 insertions(+), 514 deletions(-)
create mode 100644 fsdev/virtfs-proxy-helper.c
create mode 100644 fsdev/virtfs-proxy-helper.texi
create mode 100644 fsdev/virtio-9p-marshal.c
create mode 100644 fsdev/virtio-9p-marshal.h
create mode 100644 hw/9pfs/virtio-9p-proxy.c
create mode 100644 hw/9pfs/virtio-9p-proxy.h
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [Qemu-devel] [PULL] VirtFS Proxy FS driver changes
2012-01-04 16:28 [Qemu-devel] [PULL] VirtFS Proxy FS driver changes Aneesh Kumar K.V
@ 2012-01-09 14:52 ` Anthony Liguori
0 siblings, 0 replies; 2+ messages in thread
From: Anthony Liguori @ 2012-01-09 14:52 UTC (permalink / raw)
To: Aneesh Kumar K.V; +Cc: M. Mohan Kumar, QEMU Developers
On 01/04/2012 10:28 AM, Aneesh Kumar K.V wrote:
>
> The following changes since commit f3c6a169a39d188e98c17a0a0ebfa7f85e5aafdd:
>
> Merge remote-tracking branch 'qemu-kvm/memory/page_desc' into staging (2012-01-03 14:39:05 -0600)
>
> are available in the git repository at:
>
>
> git://github.com/kvaneesh/QEMU.git for-upstream
>
> Also available at signed tag virtfs-proxy-support
>
>
> for you to fetch changes up to 84a87cc4cc77f9e6829e20726f00646afe12deed:
>
> hw/9pfs: Add support to use named socket for proxy FS (2012-01-04 21:23:55 +0530)
Pulled. Thanks.
Regards,
Anthony Liguori
>
> ----------------------------------------------------------------
> Pass-through security model in QEMU 9p server needs root privilege to do
> few file operations (like chown, chmod to any mode/uid:gid). There are two
> issues in pass-through security model
>
> 1) TOCTTOU vulnerability: Following symbolic links in the server could
> provide access to files beyond 9p export path.
>
> 2) Running QEMU with root privilege could be a security issue.
>
> To overcome above issues, following approach is used: A new filesytem
> type 'proxy' is introduced. Proxy FS uses chroot + socket combination
> for securing the vulnerability known with following symbolic links.
> Intention of adding a new filesystem type is to allow qemu to run
> in non-root mode, but doing privileged operations using socket IO.
>
> Proxy helper(a stand alone binary part of qemu) is invoked with
> root privileges. Proxy helper chroots into 9p export path and creates
> a socket pair or a named socket based on the command line parameter.
> Qemu and proxy helper communicate using this socket. QEMU proxy fs
> driver sends filesystem request to proxy helper and receives the
> response from it.
>
> Proxy helper is designed so that it can drop the root privilege but
> retaining capbilities that are needed for doing filesystem operations
> (like CAP_DAC_OVERRIDE, CAP_FOWNER etc)
>
> ----------------------------------------------------------------
> Aneesh Kumar K.V (1):
> hw/9pfs: Move opt validation to FsDriver callback
>
> M. Mohan Kumar (13):
> hw/9pfs: Move pdu_marshal/unmarshal code to a seperate file
> hw/9pfs: Add validation to {un}marshal code
> hw/9pfs: Add new proxy filesystem driver
> hw/9pfs: File system helper process for qemu 9p proxy FS
> hw/9pfs: Open and create files
> hw/9pfs: Create other filesystem objects
> hw/9pfs: Add stat/readlink/statfs for proxy FS
> hw/9pfs: File ownership and others
> hw/9pfs: xattr interfaces in proxy filesystem driver
> hw/9pfs: Proxy getversion
> hw/9pfs: Documentation changes related to proxy fs
> hw/9pfs: man page for proxy helper
> hw/9pfs: Add support to use named socket for proxy FS
>
> Makefile | 15 +-
> Makefile.objs | 3 +-
> configure | 19 +
> fsdev/file-op-9p.h | 17 +-
> fsdev/qemu-fsdev.c | 45 +--
> fsdev/qemu-fsdev.h | 11 +-
> fsdev/virtfs-proxy-helper.c | 1120 +++++++++++++++++++++++++++++++++++++
> fsdev/virtfs-proxy-helper.texi | 63 +++
> fsdev/virtio-9p-marshal.c | 323 +++++++++++
> fsdev/virtio-9p-marshal.h | 90 +++
> hw/9pfs/virtio-9p-device.c | 13 +-
> hw/9pfs/virtio-9p-handle.c | 20 +
> hw/9pfs/virtio-9p-local.c | 34 ++
> hw/9pfs/virtio-9p-proxy.c | 1210 ++++++++++++++++++++++++++++++++++++++++
> hw/9pfs/virtio-9p-proxy.h | 95 ++++
> hw/9pfs/virtio-9p.c | 704 +++++++++++------------
> hw/9pfs/virtio-9p.h | 83 +---
> qemu-config.c | 13 +
> qemu-options.hx | 32 +-
> vl.c | 18 +-
> 20 files changed, 3414 insertions(+), 514 deletions(-)
> create mode 100644 fsdev/virtfs-proxy-helper.c
> create mode 100644 fsdev/virtfs-proxy-helper.texi
> create mode 100644 fsdev/virtio-9p-marshal.c
> create mode 100644 fsdev/virtio-9p-marshal.h
> create mode 100644 hw/9pfs/virtio-9p-proxy.c
> create mode 100644 hw/9pfs/virtio-9p-proxy.h
>
>
>
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2012-01-04 16:28 [Qemu-devel] [PULL] VirtFS Proxy FS driver changes Aneesh Kumar K.V
2012-01-09 14:52 ` Anthony Liguori
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