tools/virtiofsd: add support for --socket-group

Message ID 20200312104142.21259-1-alex.bennee@linaro.org
State New
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  • tools/virtiofsd: add support for --socket-group
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Commit Message

Alex Bennée March 12, 2020, 10:41 a.m.
If you like running QEMU as a normal user (very common for TCG runs)
but you have to run virtiofsd as a root user you run into connection
problems. Adding support for an optional --socket-group allows the
users to keep using the command line.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>


---
v1
  - tweak documentation and commentary
---
 docs/tools/virtiofsd.rst        |  4 ++++
 tools/virtiofsd/fuse_i.h        |  1 +
 tools/virtiofsd/fuse_lowlevel.c |  6 ++++++
 tools/virtiofsd/fuse_virtio.c   | 20 ++++++++++++++++++--
 4 files changed, 29 insertions(+), 2 deletions(-)

-- 
2.20.1

Comments

Daniel P. Berrangé March 12, 2020, 10:49 a.m. | #1
On Thu, Mar 12, 2020 at 10:41:42AM +0000, Alex Bennée wrote:
> If you like running QEMU as a normal user (very common for TCG runs)

> but you have to run virtiofsd as a root user you run into connection

> problems. Adding support for an optional --socket-group allows the

> users to keep using the command line.


If we're going to support this, then I think we need to put it in
the vhost-user.rst specification so we standardize across backends. 



> Signed-off-by: Alex Bennée <alex.bennee@linaro.org>



> 

> ---

> v1

>   - tweak documentation and commentary

> ---

>  docs/tools/virtiofsd.rst        |  4 ++++

>  tools/virtiofsd/fuse_i.h        |  1 +

>  tools/virtiofsd/fuse_lowlevel.c |  6 ++++++

>  tools/virtiofsd/fuse_virtio.c   | 20 ++++++++++++++++++--

>  4 files changed, 29 insertions(+), 2 deletions(-)

> 

> diff --git a/docs/tools/virtiofsd.rst b/docs/tools/virtiofsd.rst

> index 378594c422a..5a8246b74f8 100644

> --- a/docs/tools/virtiofsd.rst

> +++ b/docs/tools/virtiofsd.rst

> @@ -85,6 +85,10 @@ Options

>  

>    Listen on vhost-user UNIX domain socket at PATH.

>  

> +.. option:: --socket-group=GROUP

> +

> +  Set the vhost-user UNIX domain socket gid to GROUP.

> +

>  .. option:: --fd=FDNUM

>  

>    Accept connections from vhost-user UNIX domain socket file descriptor FDNUM.

> diff --git a/tools/virtiofsd/fuse_i.h b/tools/virtiofsd/fuse_i.h

> index 1240828208a..492e002181e 100644

> --- a/tools/virtiofsd/fuse_i.h

> +++ b/tools/virtiofsd/fuse_i.h

> @@ -68,6 +68,7 @@ struct fuse_session {

>      size_t bufsize;

>      int error;

>      char *vu_socket_path;

> +    char *vu_socket_group;

>      int   vu_listen_fd;

>      int   vu_socketfd;

>      struct fv_VuDev *virtio_dev;

> diff --git a/tools/virtiofsd/fuse_lowlevel.c b/tools/virtiofsd/fuse_lowlevel.c

> index 2dd36ec03b6..4d1ba2925d1 100644

> --- a/tools/virtiofsd/fuse_lowlevel.c

> +++ b/tools/virtiofsd/fuse_lowlevel.c

> @@ -2523,6 +2523,7 @@ static const struct fuse_opt fuse_ll_opts[] = {

>      LL_OPTION("--debug", debug, 1),

>      LL_OPTION("allow_root", deny_others, 1),

>      LL_OPTION("--socket-path=%s", vu_socket_path, 0),

> +    LL_OPTION("--socket-group=%s", vu_socket_group, 0),

>      LL_OPTION("--fd=%d", vu_listen_fd, 0),

>      LL_OPTION("--thread-pool-size=%d", thread_pool_size, 0),

>      FUSE_OPT_END

> @@ -2630,6 +2631,11 @@ struct fuse_session *fuse_session_new(struct fuse_args *args,

>                   "fuse: --socket-path and --fd cannot be given together\n");

>          goto out4;

>      }

> +    if (se->vu_socket_group && !se->vu_socket_path) {

> +        fuse_log(FUSE_LOG_ERR,

> +                 "fuse: --socket-group can only be used with --socket-path\n");

> +        goto out4;

> +    }

>  

>      se->bufsize = FUSE_MAX_MAX_PAGES * getpagesize() + FUSE_BUFFER_HEADER_SIZE;

>  

> diff --git a/tools/virtiofsd/fuse_virtio.c b/tools/virtiofsd/fuse_virtio.c

> index 3b6d16a0417..331f9fc65c5 100644

> --- a/tools/virtiofsd/fuse_virtio.c

> +++ b/tools/virtiofsd/fuse_virtio.c

> @@ -31,6 +31,8 @@

>  #include <sys/socket.h>

>  #include <sys/types.h>

>  #include <sys/un.h>

> +#include <sys/types.h>

> +#include <grp.h>

>  #include <unistd.h>

>  

>  #include "contrib/libvhost-user/libvhost-user.h"

> @@ -924,15 +926,29 @@ static int fv_create_listen_socket(struct fuse_session *se)

>  

>      /*

>       * Unfortunately bind doesn't let you set the mask on the socket,

> -     * so set umask to 077 and restore it later.

> +     * so set umask appropriately and restore it later.

>       */

> -    old_umask = umask(0077);

> +    if (se->vu_socket_group) {

> +        old_umask = umask(S_IROTH | S_IWOTH | S_IXOTH);

> +    } else {

> +        old_umask = umask(S_IRGRP | S_IWGRP | S_IXGRP | S_IROTH | S_IWOTH | S_IXOTH);

> +    }

>      if (bind(listen_sock, (struct sockaddr *)&un, addr_len) == -1) {

>          fuse_log(FUSE_LOG_ERR, "vhost socket bind: %m\n");

>          close(listen_sock);

>          umask(old_umask);

>          return -1;

>      }

> +    if (se->vu_socket_group) {

> +        struct group *g = getgrnam(se->vu_socket_group);

> +        if (g) {

> +            if (!chown(se->vu_socket_path, -1, g->gr_gid)) {

> +                fuse_log(FUSE_LOG_WARNING,

> +                         "vhost socket failed to set group to %s (%d)\n",

> +                         se->vu_socket_group, g->gr_gid);

> +            }

> +        }

> +    }

>      umask(old_umask);

>  

>      if (listen(listen_sock, 1) == -1) {

> -- 

> 2.20.1

> 

> 


Regards,
Daniel
-- 
|: https://berrange.com      -o-    https://www.flickr.com/photos/dberrange :|
|: https://libvirt.org         -o-            https://fstop138.berrange.com :|
|: https://entangle-photo.org    -o-    https://www.instagram.com/dberrange :|
Stefan Hajnoczi March 14, 2020, 1:25 p.m. | #2
On Thu, Mar 12, 2020 at 10:41:42AM +0000, Alex Bennée wrote:
> If you like running QEMU as a normal user (very common for TCG runs)

> but you have to run virtiofsd as a root user you run into connection

> problems. Adding support for an optional --socket-group allows the

> users to keep using the command line.

> 

> Signed-off-by: Alex Bennée <alex.bennee@linaro.org>

> 

> ---

> v1

>   - tweak documentation and commentary

> ---

>  docs/tools/virtiofsd.rst        |  4 ++++

>  tools/virtiofsd/fuse_i.h        |  1 +

>  tools/virtiofsd/fuse_lowlevel.c |  6 ++++++

>  tools/virtiofsd/fuse_virtio.c   | 20 ++++++++++++++++++--

>  4 files changed, 29 insertions(+), 2 deletions(-)


Dan's suggestion sounds like a good idea to me.

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Marc-André Lureau March 14, 2020, 1:33 p.m. | #3
Hi

On Thu, Mar 12, 2020 at 11:49 AM Daniel P. Berrangé <berrange@redhat.com> wrote:
>

> On Thu, Mar 12, 2020 at 10:41:42AM +0000, Alex Bennée wrote:

> > If you like running QEMU as a normal user (very common for TCG runs)

> > but you have to run virtiofsd as a root user you run into connection

> > problems. Adding support for an optional --socket-group allows the

> > users to keep using the command line.

>

> If we're going to support this, then I think we need to put it in

> the vhost-user.rst specification so we standardize across backends.

>

>


Perhaps. Otoh, I wonder if the backend spec should be more limited to
arguments/introspection that are used by programs.

In this case, I even consider --socket-path to be unnecessary, as a
management layer can/should provide a preopened & setup fd directly.

What do you think?

>

> > Signed-off-by: Alex Bennée <alex.bennee@linaro.org>

>

>

> >

> > ---

> > v1

> >   - tweak documentation and commentary

> > ---

> >  docs/tools/virtiofsd.rst        |  4 ++++

> >  tools/virtiofsd/fuse_i.h        |  1 +

> >  tools/virtiofsd/fuse_lowlevel.c |  6 ++++++

> >  tools/virtiofsd/fuse_virtio.c   | 20 ++++++++++++++++++--

> >  4 files changed, 29 insertions(+), 2 deletions(-)

> >

> > diff --git a/docs/tools/virtiofsd.rst b/docs/tools/virtiofsd.rst

> > index 378594c422a..5a8246b74f8 100644

> > --- a/docs/tools/virtiofsd.rst

> > +++ b/docs/tools/virtiofsd.rst

> > @@ -85,6 +85,10 @@ Options

> >

> >    Listen on vhost-user UNIX domain socket at PATH.

> >

> > +.. option:: --socket-group=GROUP

> > +

> > +  Set the vhost-user UNIX domain socket gid to GROUP.

> > +

> >  .. option:: --fd=FDNUM

> >

> >    Accept connections from vhost-user UNIX domain socket file descriptor FDNUM.

> > diff --git a/tools/virtiofsd/fuse_i.h b/tools/virtiofsd/fuse_i.h

> > index 1240828208a..492e002181e 100644

> > --- a/tools/virtiofsd/fuse_i.h

> > +++ b/tools/virtiofsd/fuse_i.h

> > @@ -68,6 +68,7 @@ struct fuse_session {

> >      size_t bufsize;

> >      int error;

> >      char *vu_socket_path;

> > +    char *vu_socket_group;

> >      int   vu_listen_fd;

> >      int   vu_socketfd;

> >      struct fv_VuDev *virtio_dev;

> > diff --git a/tools/virtiofsd/fuse_lowlevel.c b/tools/virtiofsd/fuse_lowlevel.c

> > index 2dd36ec03b6..4d1ba2925d1 100644

> > --- a/tools/virtiofsd/fuse_lowlevel.c

> > +++ b/tools/virtiofsd/fuse_lowlevel.c

> > @@ -2523,6 +2523,7 @@ static const struct fuse_opt fuse_ll_opts[] = {

> >      LL_OPTION("--debug", debug, 1),

> >      LL_OPTION("allow_root", deny_others, 1),

> >      LL_OPTION("--socket-path=%s", vu_socket_path, 0),

> > +    LL_OPTION("--socket-group=%s", vu_socket_group, 0),

> >      LL_OPTION("--fd=%d", vu_listen_fd, 0),

> >      LL_OPTION("--thread-pool-size=%d", thread_pool_size, 0),

> >      FUSE_OPT_END

> > @@ -2630,6 +2631,11 @@ struct fuse_session *fuse_session_new(struct fuse_args *args,

> >                   "fuse: --socket-path and --fd cannot be given together\n");

> >          goto out4;

> >      }

> > +    if (se->vu_socket_group && !se->vu_socket_path) {

> > +        fuse_log(FUSE_LOG_ERR,

> > +                 "fuse: --socket-group can only be used with --socket-path\n");

> > +        goto out4;

> > +    }

> >

> >      se->bufsize = FUSE_MAX_MAX_PAGES * getpagesize() + FUSE_BUFFER_HEADER_SIZE;

> >

> > diff --git a/tools/virtiofsd/fuse_virtio.c b/tools/virtiofsd/fuse_virtio.c

> > index 3b6d16a0417..331f9fc65c5 100644

> > --- a/tools/virtiofsd/fuse_virtio.c

> > +++ b/tools/virtiofsd/fuse_virtio.c

> > @@ -31,6 +31,8 @@

> >  #include <sys/socket.h>

> >  #include <sys/types.h>

> >  #include <sys/un.h>

> > +#include <sys/types.h>

> > +#include <grp.h>

> >  #include <unistd.h>

> >

> >  #include "contrib/libvhost-user/libvhost-user.h"

> > @@ -924,15 +926,29 @@ static int fv_create_listen_socket(struct fuse_session *se)

> >

> >      /*

> >       * Unfortunately bind doesn't let you set the mask on the socket,

> > -     * so set umask to 077 and restore it later.

> > +     * so set umask appropriately and restore it later.

> >       */

> > -    old_umask = umask(0077);

> > +    if (se->vu_socket_group) {

> > +        old_umask = umask(S_IROTH | S_IWOTH | S_IXOTH);

> > +    } else {

> > +        old_umask = umask(S_IRGRP | S_IWGRP | S_IXGRP | S_IROTH | S_IWOTH | S_IXOTH);

> > +    }

> >      if (bind(listen_sock, (struct sockaddr *)&un, addr_len) == -1) {

> >          fuse_log(FUSE_LOG_ERR, "vhost socket bind: %m\n");

> >          close(listen_sock);

> >          umask(old_umask);

> >          return -1;

> >      }

> > +    if (se->vu_socket_group) {

> > +        struct group *g = getgrnam(se->vu_socket_group);

> > +        if (g) {

> > +            if (!chown(se->vu_socket_path, -1, g->gr_gid)) {

> > +                fuse_log(FUSE_LOG_WARNING,

> > +                         "vhost socket failed to set group to %s (%d)\n",

> > +                         se->vu_socket_group, g->gr_gid);

> > +            }

> > +        }

> > +    }

> >      umask(old_umask);

> >

> >      if (listen(listen_sock, 1) == -1) {

> > --

> > 2.20.1

> >

> >

>

> Regards,

> Daniel

> --

> |: https://berrange.com      -o-    https://www.flickr.com/photos/dberrange :|

> |: https://libvirt.org         -o-            https://fstop138.berrange.com :|

> |: https://entangle-photo.org    -o-    https://www.instagram.com/dberrange :|

>

>



-- 
Marc-André Lureau
Daniel P. Berrangé March 16, 2020, 10:33 a.m. | #4
On Sat, Mar 14, 2020 at 02:33:25PM +0100, Marc-André Lureau wrote:
> Hi

> 

> On Thu, Mar 12, 2020 at 11:49 AM Daniel P. Berrangé <berrange@redhat.com> wrote:

> >

> > On Thu, Mar 12, 2020 at 10:41:42AM +0000, Alex Bennée wrote:

> > > If you like running QEMU as a normal user (very common for TCG runs)

> > > but you have to run virtiofsd as a root user you run into connection

> > > problems. Adding support for an optional --socket-group allows the

> > > users to keep using the command line.

> >

> > If we're going to support this, then I think we need to put it in

> > the vhost-user.rst specification so we standardize across backends.

> >

> >

> 

> Perhaps. Otoh, I wonder if the backend spec should be more limited to

> arguments/introspection that are used by programs.

> 

> In this case, I even consider --socket-path to be unnecessary, as a

> management layer can/should provide a preopened & setup fd directly.

> 

> What do you think?


I think there's value in standardization even if it is an option targetted
at human admins, rather than machine usage. You are right though that
something like libvirt would never use --socket-group, or --socket-path.
Even admins would benefit if all programs followed the same naming for
these.  We could document such options as "SHOULD" rather than "MUST"
IOW, we don't mandate --socket-group, but if you're going to provide a
way to control socket group, this option should be used.


Regards,
Daniel
-- 
|: https://berrange.com      -o-    https://www.flickr.com/photos/dberrange :|
|: https://libvirt.org         -o-            https://fstop138.berrange.com :|
|: https://entangle-photo.org    -o-    https://www.instagram.com/dberrange :|
Stefan Hajnoczi March 17, 2020, 9:54 a.m. | #5
On Mon, Mar 16, 2020 at 10:33:31AM +0000, Daniel P. Berrangé wrote:
> On Sat, Mar 14, 2020 at 02:33:25PM +0100, Marc-André Lureau wrote:

> > Hi

> > 

> > On Thu, Mar 12, 2020 at 11:49 AM Daniel P. Berrangé <berrange@redhat.com> wrote:

> > >

> > > On Thu, Mar 12, 2020 at 10:41:42AM +0000, Alex Bennée wrote:

> > > > If you like running QEMU as a normal user (very common for TCG runs)

> > > > but you have to run virtiofsd as a root user you run into connection

> > > > problems. Adding support for an optional --socket-group allows the

> > > > users to keep using the command line.

> > >

> > > If we're going to support this, then I think we need to put it in

> > > the vhost-user.rst specification so we standardize across backends.

> > >

> > >

> > 

> > Perhaps. Otoh, I wonder if the backend spec should be more limited to

> > arguments/introspection that are used by programs.

> > 

> > In this case, I even consider --socket-path to be unnecessary, as a

> > management layer can/should provide a preopened & setup fd directly.

> > 

> > What do you think?

> 

> I think there's value in standardization even if it is an option targetted

> at human admins, rather than machine usage. You are right though that

> something like libvirt would never use --socket-group, or --socket-path.

> Even admins would benefit if all programs followed the same naming for

> these.  We could document such options as "SHOULD" rather than "MUST"

> IOW, we don't mandate --socket-group, but if you're going to provide a

> way to control socket group, this option should be used.


I agree.  It's still useful to have a convention that most vhost-user
backend programs follow.

Stefan
Dr. David Alan Gilbert March 17, 2020, 6:47 p.m. | #6
* Stefan Hajnoczi (stefanha@redhat.com) wrote:
> On Mon, Mar 16, 2020 at 10:33:31AM +0000, Daniel P. Berrangé wrote:

> > On Sat, Mar 14, 2020 at 02:33:25PM +0100, Marc-André Lureau wrote:

> > > Hi

> > > 

> > > On Thu, Mar 12, 2020 at 11:49 AM Daniel P. Berrangé <berrange@redhat.com> wrote:

> > > >

> > > > On Thu, Mar 12, 2020 at 10:41:42AM +0000, Alex Bennée wrote:

> > > > > If you like running QEMU as a normal user (very common for TCG runs)

> > > > > but you have to run virtiofsd as a root user you run into connection

> > > > > problems. Adding support for an optional --socket-group allows the

> > > > > users to keep using the command line.

> > > >

> > > > If we're going to support this, then I think we need to put it in

> > > > the vhost-user.rst specification so we standardize across backends.

> > > >

> > > >

> > > 

> > > Perhaps. Otoh, I wonder if the backend spec should be more limited to

> > > arguments/introspection that are used by programs.

> > > 

> > > In this case, I even consider --socket-path to be unnecessary, as a

> > > management layer can/should provide a preopened & setup fd directly.

> > > 

> > > What do you think?

> > 

> > I think there's value in standardization even if it is an option targetted

> > at human admins, rather than machine usage. You are right though that

> > something like libvirt would never use --socket-group, or --socket-path.

> > Even admins would benefit if all programs followed the same naming for

> > these.  We could document such options as "SHOULD" rather than "MUST"

> > IOW, we don't mandate --socket-group, but if you're going to provide a

> > way to control socket group, this option should be used.

> 

> I agree.  It's still useful to have a convention that most vhost-user

> backend programs follow.


Alex:
  Can you add the doc entry that Stefan and Marc-André are asking
for;  it's probably good they go together.

Dave

> Stefan



--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
Alex Bennée March 17, 2020, 11:21 p.m. | #7
Dr. David Alan Gilbert <dgilbert@redhat.com> writes:

> * Stefan Hajnoczi (stefanha@redhat.com) wrote:

>> On Mon, Mar 16, 2020 at 10:33:31AM +0000, Daniel P. Berrangé wrote:

>> > On Sat, Mar 14, 2020 at 02:33:25PM +0100, Marc-André Lureau wrote:

>> > > Hi

>> > > 

>> > > On Thu, Mar 12, 2020 at 11:49 AM Daniel P. Berrangé <berrange@redhat.com> wrote:

>> > > >

>> > > > On Thu, Mar 12, 2020 at 10:41:42AM +0000, Alex Bennée wrote:

>> > > > > If you like running QEMU as a normal user (very common for TCG runs)

>> > > > > but you have to run virtiofsd as a root user you run into connection

>> > > > > problems. Adding support for an optional --socket-group allows the

>> > > > > users to keep using the command line.

>> > > >

>> > > > If we're going to support this, then I think we need to put it in

>> > > > the vhost-user.rst specification so we standardize across backends.

>> > > >

>> > > >

>> > > 

>> > > Perhaps. Otoh, I wonder if the backend spec should be more limited to

>> > > arguments/introspection that are used by programs.

>> > > 

>> > > In this case, I even consider --socket-path to be unnecessary, as a

>> > > management layer can/should provide a preopened & setup fd directly.

>> > > 

>> > > What do you think?

>> > 

>> > I think there's value in standardization even if it is an option targetted

>> > at human admins, rather than machine usage. You are right though that

>> > something like libvirt would never use --socket-group, or --socket-path.

>> > Even admins would benefit if all programs followed the same naming for

>> > these.  We could document such options as "SHOULD" rather than "MUST"

>> > IOW, we don't mandate --socket-group, but if you're going to provide a

>> > way to control socket group, this option should be used.

>> 

>> I agree.  It's still useful to have a convention that most vhost-user

>> backend programs follow.

>

> Alex:

>   Can you add the doc entry that Stefan and Marc-André are asking

> for;  it's probably good they go together.


Sure - is docs/interop/vhost-user.rst the master spec for vhost-user
daemons?

>

> Dave

>

>> Stefan



-- 
Alex Bennée
Marc-André Lureau March 17, 2020, 11:54 p.m. | #8
Hi

On Wed, Mar 18, 2020 at 12:21 AM Alex Bennée <alex.bennee@linaro.org> wrote:
>

>

> Dr. David Alan Gilbert <dgilbert@redhat.com> writes:

>

> > * Stefan Hajnoczi (stefanha@redhat.com) wrote:

> >> On Mon, Mar 16, 2020 at 10:33:31AM +0000, Daniel P. Berrangé wrote:

> >> > On Sat, Mar 14, 2020 at 02:33:25PM +0100, Marc-André Lureau wrote:

> >> > > Hi

> >> > >

> >> > > On Thu, Mar 12, 2020 at 11:49 AM Daniel P. Berrangé <berrange@redhat.com> wrote:

> >> > > >

> >> > > > On Thu, Mar 12, 2020 at 10:41:42AM +0000, Alex Bennée wrote:

> >> > > > > If you like running QEMU as a normal user (very common for TCG runs)

> >> > > > > but you have to run virtiofsd as a root user you run into connection

> >> > > > > problems. Adding support for an optional --socket-group allows the

> >> > > > > users to keep using the command line.

> >> > > >

> >> > > > If we're going to support this, then I think we need to put it in

> >> > > > the vhost-user.rst specification so we standardize across backends.

> >> > > >

> >> > > >

> >> > >

> >> > > Perhaps. Otoh, I wonder if the backend spec should be more limited to

> >> > > arguments/introspection that are used by programs.

> >> > >

> >> > > In this case, I even consider --socket-path to be unnecessary, as a

> >> > > management layer can/should provide a preopened & setup fd directly.

> >> > >

> >> > > What do you think?

> >> >

> >> > I think there's value in standardization even if it is an option targetted

> >> > at human admins, rather than machine usage. You are right though that

> >> > something like libvirt would never use --socket-group, or --socket-path.

> >> > Even admins would benefit if all programs followed the same naming for

> >> > these.  We could document such options as "SHOULD" rather than "MUST"

> >> > IOW, we don't mandate --socket-group, but if you're going to provide a

> >> > way to control socket group, this option should be used.

> >>

> >> I agree.  It's still useful to have a convention that most vhost-user

> >> backend programs follow.

> >

> > Alex:

> >   Can you add the doc entry that Stefan and Marc-André are asking

> > for;  it's probably good they go together.

>

> Sure - is docs/interop/vhost-user.rst the master spec for vhost-user

> daemons?


So far, yes. But it might make sense to create a standalone
vhost-user-daemons.rst.



-- 
Marc-André Lureau

Patch

diff --git a/docs/tools/virtiofsd.rst b/docs/tools/virtiofsd.rst
index 378594c422a..5a8246b74f8 100644
--- a/docs/tools/virtiofsd.rst
+++ b/docs/tools/virtiofsd.rst
@@ -85,6 +85,10 @@  Options
 
   Listen on vhost-user UNIX domain socket at PATH.
 
+.. option:: --socket-group=GROUP
+
+  Set the vhost-user UNIX domain socket gid to GROUP.
+
 .. option:: --fd=FDNUM
 
   Accept connections from vhost-user UNIX domain socket file descriptor FDNUM.
diff --git a/tools/virtiofsd/fuse_i.h b/tools/virtiofsd/fuse_i.h
index 1240828208a..492e002181e 100644
--- a/tools/virtiofsd/fuse_i.h
+++ b/tools/virtiofsd/fuse_i.h
@@ -68,6 +68,7 @@  struct fuse_session {
     size_t bufsize;
     int error;
     char *vu_socket_path;
+    char *vu_socket_group;
     int   vu_listen_fd;
     int   vu_socketfd;
     struct fv_VuDev *virtio_dev;
diff --git a/tools/virtiofsd/fuse_lowlevel.c b/tools/virtiofsd/fuse_lowlevel.c
index 2dd36ec03b6..4d1ba2925d1 100644
--- a/tools/virtiofsd/fuse_lowlevel.c
+++ b/tools/virtiofsd/fuse_lowlevel.c
@@ -2523,6 +2523,7 @@  static const struct fuse_opt fuse_ll_opts[] = {
     LL_OPTION("--debug", debug, 1),
     LL_OPTION("allow_root", deny_others, 1),
     LL_OPTION("--socket-path=%s", vu_socket_path, 0),
+    LL_OPTION("--socket-group=%s", vu_socket_group, 0),
     LL_OPTION("--fd=%d", vu_listen_fd, 0),
     LL_OPTION("--thread-pool-size=%d", thread_pool_size, 0),
     FUSE_OPT_END
@@ -2630,6 +2631,11 @@  struct fuse_session *fuse_session_new(struct fuse_args *args,
                  "fuse: --socket-path and --fd cannot be given together\n");
         goto out4;
     }
+    if (se->vu_socket_group && !se->vu_socket_path) {
+        fuse_log(FUSE_LOG_ERR,
+                 "fuse: --socket-group can only be used with --socket-path\n");
+        goto out4;
+    }
 
     se->bufsize = FUSE_MAX_MAX_PAGES * getpagesize() + FUSE_BUFFER_HEADER_SIZE;
 
diff --git a/tools/virtiofsd/fuse_virtio.c b/tools/virtiofsd/fuse_virtio.c
index 3b6d16a0417..331f9fc65c5 100644
--- a/tools/virtiofsd/fuse_virtio.c
+++ b/tools/virtiofsd/fuse_virtio.c
@@ -31,6 +31,8 @@ 
 #include <sys/socket.h>
 #include <sys/types.h>
 #include <sys/un.h>
+#include <sys/types.h>
+#include <grp.h>
 #include <unistd.h>
 
 #include "contrib/libvhost-user/libvhost-user.h"
@@ -924,15 +926,29 @@  static int fv_create_listen_socket(struct fuse_session *se)
 
     /*
      * Unfortunately bind doesn't let you set the mask on the socket,
-     * so set umask to 077 and restore it later.
+     * so set umask appropriately and restore it later.
      */
-    old_umask = umask(0077);
+    if (se->vu_socket_group) {
+        old_umask = umask(S_IROTH | S_IWOTH | S_IXOTH);
+    } else {
+        old_umask = umask(S_IRGRP | S_IWGRP | S_IXGRP | S_IROTH | S_IWOTH | S_IXOTH);
+    }
     if (bind(listen_sock, (struct sockaddr *)&un, addr_len) == -1) {
         fuse_log(FUSE_LOG_ERR, "vhost socket bind: %m\n");
         close(listen_sock);
         umask(old_umask);
         return -1;
     }
+    if (se->vu_socket_group) {
+        struct group *g = getgrnam(se->vu_socket_group);
+        if (g) {
+            if (!chown(se->vu_socket_path, -1, g->gr_gid)) {
+                fuse_log(FUSE_LOG_WARNING,
+                         "vhost socket failed to set group to %s (%d)\n",
+                         se->vu_socket_group, g->gr_gid);
+            }
+        }
+    }
     umask(old_umask);
 
     if (listen(listen_sock, 1) == -1) {