On Saturday, June 10, 2023 3:39:44 PM CEST Christian Schoenebeck wrote: > As recent CVE-2023-2861 once again showed, the 9p 'proxy' fs driver is in > bad shape. Using the 'proxy' backend was already discouraged for safety > reasons before and we recommended to use the 'local' backend instead, > but now it is time to officially deprecate the 'proxy' backend. > > Signed-off-by: Christian Schoenebeck <qemu_...@crudebyte.com> > --- > v2 -> v3: > * Fix copy wasted typo (-> 'backend'). > > MAINTAINERS | 7 +++++++ > docs/about/deprecated.rst | 17 +++++++++++++++++ > docs/tools/virtfs-proxy-helper.rst | 3 +++ > fsdev/qemu-fsdev.c | 5 +++++ > fsdev/virtfs-proxy-helper.c | 5 +++++ > hw/9pfs/9p-proxy.c | 5 +++++ > hw/9pfs/9p-proxy.h | 5 +++++ > meson.build | 2 +- > qemu-options.hx | 6 +++++- > softmmu/vl.c | 5 +++++ > 10 files changed, 58 insertions(+), 2 deletions(-)
Or would it be better to split this up, e.g. into 3 separate patches (runtime messages, docs, MAINTAINERS)? > diff --git a/MAINTAINERS b/MAINTAINERS > index 436b3f0afe..185d694b2e 100644 > --- a/MAINTAINERS > +++ b/MAINTAINERS > @@ -2118,13 +2118,20 @@ S: Odd Fixes > W: https://wiki.qemu.org/Documentation/9p > F: hw/9pfs/ > X: hw/9pfs/xen-9p* > +X: hw/9pfs/9p-proxy* > F: fsdev/ > +X: fsdev/virtfs-proxy-helper.c > F: docs/tools/virtfs-proxy-helper.rst I missed virtfs-proxy-helper.rst here. That should be moved to the new 'proxy' section below as well. > F: tests/qtest/virtio-9p-test.c > F: tests/qtest/libqos/virtio-9p* > T: git https://gitlab.com/gkurz/qemu.git 9p-next > T: git https://github.com/cschoenebeck/qemu.git 9p.next > > +virtio-9p-proxy > +F: hw/9pfs/9p-proxy* > +F: fsdev/virtfs-proxy-helper.c > +S: Obsolete > + > virtio-blk > M: Stefan Hajnoczi <stefa...@redhat.com> > L: qemu-bl...@nongnu.org > diff --git a/docs/about/deprecated.rst b/docs/about/deprecated.rst > index 0743459862..9b2c780365 100644 > --- a/docs/about/deprecated.rst > +++ b/docs/about/deprecated.rst > @@ -343,6 +343,23 @@ the addition of volatile memory support, it is now > necessary to distinguish > between persistent and volatile memory backends. As such, memdev is > deprecated > in favor of persistent-memdev. > > +``-fsdev proxy`` and ``-virtfs proxy`` (since 8.1) > +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ > + > +The 9p ``proxy`` filesystem backend driver has been deprecated and will be > +removed in a future version of QEMU. Please use ``-fsdev local`` or > +``-virtfs local`` for using the ``local`` 9p filesystem backend instead. > + > +The 9p ``proxy`` backend was originally developed as an alternative to the 9p > +``local`` backend. The idea was to enhance security by dispatching actual low > +level filesystem operations from 9p server (QEMU process) over to a separate > +process (the virtfs-proxy-helper binary). However this alternative never > gained > +momentum. The proxy backend is much slower than the local backend, hasn't > seen > +any development in years, and showed to be less secure, especially due to the > +fact that its helper daemon must be run as root, whereas with the local > backend > +QEMU is typically run as unprivileged user and allows to tighten behaviour by > +mapping permissions et al. > + > > Block device options > '''''''''''''''''''' > diff --git a/docs/tools/virtfs-proxy-helper.rst > b/docs/tools/virtfs-proxy-helper.rst > index 6cdeedf8e9..bd310ebb07 100644 > --- a/docs/tools/virtfs-proxy-helper.rst > +++ b/docs/tools/virtfs-proxy-helper.rst > @@ -9,6 +9,9 @@ Synopsis > Description > ----------- > > +NOTE: The 9p 'proxy' backend is deprecated (since QEMU 8.1) and will be > +removed, along with this daemon, in a future version of QEMU! > + > 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: > diff --git a/fsdev/qemu-fsdev.c b/fsdev/qemu-fsdev.c > index 3da64e9f72..242f54ab49 100644 > --- a/fsdev/qemu-fsdev.c > +++ b/fsdev/qemu-fsdev.c > @@ -133,6 +133,11 @@ int qemu_fsdev_add(QemuOpts *opts, Error **errp) > } > > if (fsdriver) { > + if (strncmp(fsdriver, "proxy", 5) == 0) { > + warn_report("'-fsdev proxy' is deprecated, use '-fsdev local' " > + "instead"); > + } > + > for (i = 0; i < ARRAY_SIZE(FsDrivers); i++) { > if (strcmp(FsDrivers[i].name, fsdriver) == 0) { > break; > diff --git a/fsdev/virtfs-proxy-helper.c b/fsdev/virtfs-proxy-helper.c > index d9511f429c..5dd5d99284 100644 > --- a/fsdev/virtfs-proxy-helper.c > +++ b/fsdev/virtfs-proxy-helper.c > @@ -9,6 +9,11 @@ > * the COPYING file in the top-level directory. > */ > > +/* > + * NOTE: The 9p 'proxy' backend is deprecated (since QEMU 8.1) and will be > + * removed in a future version of QEMU! > + */ > + > #include "qemu/osdep.h" > #include <glib/gstdio.h> > #include <sys/resource.h> > diff --git a/hw/9pfs/9p-proxy.c b/hw/9pfs/9p-proxy.c > index 99d115ff0d..905cae6992 100644 > --- a/hw/9pfs/9p-proxy.c > +++ b/hw/9pfs/9p-proxy.c > @@ -15,6 +15,11 @@ > * https://wiki.qemu.org/Documentation/9p > */ > > +/* > + * NOTE: The 9p 'proxy' backend is deprecated (since QEMU 8.1) and will be > + * removed in a future version of QEMU! > + */ > + > #include "qemu/osdep.h" > #include <sys/socket.h> > #include <sys/un.h> > diff --git a/hw/9pfs/9p-proxy.h b/hw/9pfs/9p-proxy.h > index b84301d001..9be4718d3e 100644 > --- a/hw/9pfs/9p-proxy.h > +++ b/hw/9pfs/9p-proxy.h > @@ -10,6 +10,11 @@ > * the COPYING file in the top-level directory. > */ > > +/* > + * NOTE: The 9p 'proxy' backend is deprecated (since QEMU 8.1) and will be > + * removed in a future version of QEMU! > + */ > + > #ifndef QEMU_9P_PROXY_H > #define QEMU_9P_PROXY_H > > diff --git a/meson.build b/meson.build > index 34306a6205..05c01b72bb 100644 > --- a/meson.build > +++ b/meson.build > @@ -4170,7 +4170,7 @@ if have_block > summary_info += {'Block whitelist (ro)': > get_option('block_drv_ro_whitelist')} > summary_info += {'Use block whitelist in tools': > get_option('block_drv_whitelist_in_tools')} > summary_info += {'VirtFS (9P) support': have_virtfs} > - summary_info += {'VirtFS (9P) Proxy Helper support': > have_virtfs_proxy_helper} > + summary_info += {'VirtFS (9P) Proxy Helper support (deprecated)': > have_virtfs_proxy_helper} > summary_info += {'Live block migration': > config_host_data.get('CONFIG_LIVE_BLOCK_MIGRATION')} > summary_info += {'replication support': > config_host_data.get('CONFIG_REPLICATION')} > summary_info += {'bochs support': get_option('bochs').allowed()} > diff --git a/qemu-options.hx b/qemu-options.hx > index b57489d7ca..3a6c7d3ef9 100644 > --- a/qemu-options.hx > +++ b/qemu-options.hx > @@ -1735,7 +1735,9 @@ SRST > Accesses to the filesystem are done by QEMU. > > ``proxy`` > - Accesses to the filesystem are done by virtfs-proxy-helper(1). > + Accesses to the filesystem are done by virtfs-proxy-helper(1). This > + option is deprecated (since QEMU 8.1) and will be removed in a future > + version of QEMU. Use ``local`` instead. > > ``synth`` > Synthetic filesystem, only used by QTests. > @@ -1867,6 +1869,8 @@ SRST > > ``proxy`` > Accesses to the filesystem are done by virtfs-proxy-helper(1). > + This option is deprecated (since QEMU 8.1) and will be removed in a > + future version of QEMU. Use ``local`` instead. > > ``synth`` > Synthetic filesystem, only used by QTests. > diff --git a/softmmu/vl.c b/softmmu/vl.c > index b0b96f67fa..e60648b591 100644 > --- a/softmmu/vl.c > +++ b/softmmu/vl.c > @@ -3102,6 +3102,11 @@ void qemu_init(int argc, char **argv) > error_report("Usage: -virtfs fsdriver,mount_tag=tag"); > exit(1); > } > + if (strncmp(qemu_opt_get(opts, "fsdriver"), "proxy", 5) == > 0) { > + warn_report("'-virtfs proxy' is deprecated, use " > + "'-virtfs local' instead"); > + } > + > fsdev = qemu_opts_create(qemu_find_opts("fsdev"), > qemu_opts_id(opts) ?: > qemu_opt_get(opts, "mount_tag"), >
