On Mon, Feb 07, 2022 at 12:40:21PM +0000, Dr. David Alan Gilbert wrote:
> * Vivek Goyal (vgo...@redhat.com) wrote:
> > Provide an option "-o security_label/no_security_label" to enable/disable
> > security label functionality. By default these are turned off.
> >
> > If enabled, server will indicate to client that it is capable of handling
> > one security label during file creation. Typically this is expected to
> > be a SELinux label. File server will set this label on the file. It will
> > try to set it atomically wherever possible. But its not possible in
> > all the cases.
> >
> > Signed-off-by: Vivek Goyal <vgo...@redhat.com>
> > ---
> > docs/tools/virtiofsd.rst | 7 +++++++
> > tools/virtiofsd/helper.c | 1 +
> > tools/virtiofsd/passthrough_ll.c | 15 +++++++++++++++
> > 3 files changed, 23 insertions(+)
> >
> > diff --git a/docs/tools/virtiofsd.rst b/docs/tools/virtiofsd.rst
> > index 07ac0be551..a2c005f4a0 100644
> > --- a/docs/tools/virtiofsd.rst
> > +++ b/docs/tools/virtiofsd.rst
> > @@ -104,6 +104,13 @@ Options
> > * posix_acl|no_posix_acl -
> > Enable/disable posix acl support. Posix ACLs are disabled by default.
> >
> > + * security_label|no_security_label -
> > + Enable/disable security label support. Security labels are disabled by
> > + default. This will allow client to send a MAC label of file during
> ^ the ^ a
> > + file creation. Typically this is expected to be SELinux security
> ^ an
>
> > + label. Server will try to set that label on newly created file
> ^The server
> > + atomically wherever possible.
> > +
> > .. option:: --socket-path=PATH
> >
> > Listen on vhost-user UNIX domain socket at PATH.
> > diff --git a/tools/virtiofsd/helper.c b/tools/virtiofsd/helper.c
> > index a8295d975a..e226fc590f 100644
> > --- a/tools/virtiofsd/helper.c
> > +++ b/tools/virtiofsd/helper.c
> > @@ -187,6 +187,7 @@ void fuse_cmdline_help(void)
> > " default: no_allow_direct_io\n"
> > " -o announce_submounts Announce sub-mount points to
> > the guest\n"
> > " -o posix_acl/no_posix_acl Enable/Disable posix_acl.
> > (default: disabled)\n"
> > + " -o security_label/no_security_label Enable/Disable
> > security label. (default: disabled)\n"
> > );
> > }
> >
> > diff --git a/tools/virtiofsd/passthrough_ll.c
> > b/tools/virtiofsd/passthrough_ll.c
> > index 43c9b6dbe5..fe8f3ccbb6 100644
> > --- a/tools/virtiofsd/passthrough_ll.c
> > +++ b/tools/virtiofsd/passthrough_ll.c
> > @@ -181,6 +181,7 @@ struct lo_data {
> > int user_posix_acl, posix_acl;
> > /* Keeps track if /proc/<pid>/attr/fscreate should be used or not */
> > bool use_fscreate;
> > + int user_security_label;
> > };
> >
> > static const struct fuse_opt lo_opts[] = {
> > @@ -215,6 +216,8 @@ static const struct fuse_opt lo_opts[] = {
> > { "no_killpriv_v2", offsetof(struct lo_data, user_killpriv_v2), 0 },
> > { "posix_acl", offsetof(struct lo_data, user_posix_acl), 1 },
> > { "no_posix_acl", offsetof(struct lo_data, user_posix_acl), 0 },
> > + { "security_label", offsetof(struct lo_data, user_security_label), 1 },
> > + { "no_security_label", offsetof(struct lo_data, user_security_label),
> > 0 },
> > FUSE_OPT_END
> > };
> > static bool use_syslog = false;
> > @@ -771,6 +774,17 @@ static void lo_init(void *userdata, struct
> > fuse_conn_info *conn)
> > fuse_log(FUSE_LOG_DEBUG, "lo_init: disabling posix_acl\n");
> > conn->want &= ~FUSE_CAP_POSIX_ACL;
> > }
> > +
> > + if (lo->user_security_label == 1) {
> > + if (!(conn->capable & FUSE_CAP_SECURITY_CTX)) {
> > + fuse_log(FUSE_LOG_ERR, "lo_init: Can not enable security
> > label."
> > + " kernel does not support FUSE_SECURITY_CTX
> > capability.\n");
> > + }
>
> Do you need to exit in this case - or at least clear the flag?
Actually we don't have to necessarily exit here because fuse_lowlevel.c
has a check which makes it exit. And that's why I do not clear the
flag from ->want to signifiy that filesystem wants that capability
but client is not ->capable so error out and exit.
if (se->conn.want & (~se->conn.capable)) {
fuse_log(FUSE_LOG_ERR,
"fuse: error: filesystem requested capabilities "
"0x%llx that are not supported by kernel, aborting.\n",
se->conn.want & (~se->conn.capable));
fuse_reply_err(req, EPROTO);
se->error = -EPROTO;
fuse_session_exit(se);
return;
}
Thanks
Vivek
>
> Dave
>
> > + conn->want |= FUSE_CAP_SECURITY_CTX;
> > + } else {
> > + fuse_log(FUSE_LOG_DEBUG, "lo_init: disabling security label\n");
> > + conn->want &= ~FUSE_CAP_SECURITY_CTX;
> > + }
> > }
> >
> > static void lo_getattr(fuse_req_t req, fuse_ino_t ino,
> > @@ -4279,6 +4293,7 @@ int main(int argc, char *argv[])
> > .proc_self_task = -1,
> > .user_killpriv_v2 = -1,
> > .user_posix_acl = -1,
> > + .user_security_label = -1,
> > };
> > struct lo_map_elem *root_elem;
> > struct lo_map_elem *reserve_elem;
> > --
> > 2.34.1
> >
> --
> Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK
>
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