On Tue, 2023-03-21 at 14:05 +0000, Chuck Lever III wrote:
>
> > On Mar 21, 2023, at 7:50 AM, Jeff Layton <jlayton@xxxxxxxxxx> wrote:
> >
> > On Mon, 2023-03-20 at 10:24 -0400, Chuck Lever wrote:
> > > From: Chuck Lever <chuck.lever@xxxxxxxxxx>
> > >
> > > Enable administrators to require clients to use transport layer
> > > security when accessing particular exports.
> >
> > > Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
> > > ---
> > > fs/nfsd/export.c | 53 ++++++++++++++++++++++++++++++++++++++++++++++++++---
> > > fs/nfsd/export.h | 11 +++++++++++
> > > 2 files changed, 61 insertions(+), 3 deletions(-)
> > >
> > > diff --git a/fs/nfsd/export.c b/fs/nfsd/export.c
> > > index 668c7527b17e..171ebc21bf07 100644
> > > --- a/fs/nfsd/export.c
> > > +++ b/fs/nfsd/export.c
> > > @@ -439,7 +439,6 @@ static int check_export(struct path *path, int *flags, unsigned char *uuid)
> > > return -EINVAL;
> > > }
> > > return 0;
> > > -
> > > }
> > >
> > > #ifdef CONFIG_NFSD_V4
> > > @@ -546,6 +545,31 @@ static inline int
> > > secinfo_parse(char **mesg, char *buf, struct svc_export *exp) { return 0; }
> > > #endif
> > >
> > > +static int xprtsec_parse(char **mesg, char *buf, struct svc_export *exp)
> > > +{
> > > + unsigned int i, mode, listsize;
> > > + int err;
> > > +
> > > + err = get_uint(mesg, &listsize);
> > > + if (err)
> > > + return err;
> > > + if (listsize > 3)
> > > + return -EINVAL;
> >
> > Might want to make a note that the limit of 3 here is arbitrary, and
> > that it might need to be lifted in the future (if/when we grow other
> > xprtsec options).
>
> Well I can easily add a symbolic constant for that too. I
> missed this one in the final clean-up before posting.
>
> The bigger question is whether the new downcall parameter is
> sensible. If there's a nicer way for mountd to get this
> information to the kernel, I'm open to suggestion.
>
I don't know of one. Export options seem fine here, since that's how we
control all sorts of options in the nfs server.
>
> > > +
> > > + exp->ex_xprtsec_modes = 0;
> > > + for (i = 0; i < listsize; i++) {
> > > + err = get_uint(mesg, &mode);
> > > + if (err)
> > > + return err;
> > > + mode--;
> > > + if (mode > 2)
> > > + return -EINVAL;
> > > + /* Ad hoc */
> > > + exp->ex_xprtsec_modes |= 1 << mode;
> > > + }
> > > + return 0;
> > > +}
> > > +
> > > static inline int
> > > nfsd_uuid_parse(char **mesg, char *buf, unsigned char **puuid)
> > > {
> > > @@ -608,6 +632,7 @@ static int svc_export_parse(struct cache_detail *cd, char *mesg, int mlen)
> > > exp.ex_client = dom;
> > > exp.cd = cd;
> > > exp.ex_devid_map = NULL;
> > > + exp.ex_xprtsec_modes = NFSEXP_XPRTSEC_ALL;
> > >
> > > /* expiry */
> > > err = -EINVAL;
> > > @@ -650,6 +675,8 @@ static int svc_export_parse(struct cache_detail *cd, char *mesg, int mlen)
> > > err = nfsd_uuid_parse(&mesg, buf, &exp.ex_uuid);
> > > else if (strcmp(buf, "secinfo") == 0)
> > > err = secinfo_parse(&mesg, buf, &exp);
> > > + else if (strcmp(buf, "xprtsec") == 0)
> > > + err = xprtsec_parse(&mesg, buf, &exp);
> > > else
> > > /* quietly ignore unknown words and anything
> > > * following. Newer user-space can try to set
> > > @@ -663,6 +690,7 @@ static int svc_export_parse(struct cache_detail *cd, char *mesg, int mlen)
> > > err = check_export(&exp.ex_path, &exp.ex_flags, exp.ex_uuid);
> > > if (err)
> > > goto out4;
> > > +
> > > /*
> > > * No point caching this if it would immediately expire.
> > > * Also, this protects exportfs's dummy export from the
> > > @@ -824,6 +852,7 @@ static void export_update(struct cache_head *cnew, struct cache_head *citem)
> > > for (i = 0; i < MAX_SECINFO_LIST; i++) {
> > > new->ex_flavors[i] = item->ex_flavors[i];
> > > }
> > > + new->ex_xprtsec_modes = item->ex_xprtsec_modes;
> > > }
> > >
> > > static struct cache_head *svc_export_alloc(void)
> > > @@ -1035,9 +1064,26 @@ static struct svc_export *exp_find(struct cache_detail *cd,
> > >
> > > __be32 check_nfsd_access(struct svc_export *exp, struct svc_rqst *rqstp)
> > > {
> > > - struct exp_flavor_info *f;
> > > - struct exp_flavor_info *end = exp->ex_flavors + exp->ex_nflavors;
> > > + struct exp_flavor_info *f, *end = exp->ex_flavors + exp->ex_nflavors;
> > > + struct svc_xprt *xprt = rqstp->rq_xprt;
> > > +
> > > + if (exp->ex_xprtsec_modes & NFSEXP_XPRTSEC_NONE) {
> > > + if (!test_bit(XPT_TLS_SESSION, &xprt->xpt_flags))
> > > + goto ok;
> > > + }
> > > + if (exp->ex_xprtsec_modes & NFSEXP_XPRTSEC_TLS) {
> > > + if (test_bit(XPT_TLS_SESSION, &xprt->xpt_flags) &&
> > > + !test_bit(XPT_PEER_AUTH, &xprt->xpt_flags))
> > > + goto ok;
> > > + }
> > > + if (exp->ex_xprtsec_modes & NFSEXP_XPRTSEC_MTLS) {
> > > + if (test_bit(XPT_TLS_SESSION, &xprt->xpt_flags) &&
> > > + test_bit(XPT_PEER_AUTH, &xprt->xpt_flags))
> > > + goto ok;
> > > + }
> > > + goto denied;
> > >
> > > +ok:
> > > /* legacy gss-only clients are always OK: */
> > > if (exp->ex_client == rqstp->rq_gssclient)
> > > return 0;
> > > @@ -1062,6 +1108,7 @@ __be32 check_nfsd_access(struct svc_export *exp, struct svc_rqst *rqstp)
> > > if (nfsd4_spo_must_allow(rqstp))
> > > return 0;
> > >
> > > +denied:
> > > return rqstp->rq_vers < 4 ? nfserr_acces : nfserr_wrongsec;
> > > }
> > >
> > > diff --git a/fs/nfsd/export.h b/fs/nfsd/export.h
> > > index d03f7f6a8642..61e1e8383c3d 100644
> > > --- a/fs/nfsd/export.h
> > > +++ b/fs/nfsd/export.h
> > > @@ -77,8 +77,19 @@ struct svc_export {
> > > struct cache_detail *cd;
> > > struct rcu_head ex_rcu;
> > > struct export_stats ex_stats;
> > > + unsigned long ex_xprtsec_modes;
> > > };
> > >
> > > +enum {
> > > + NFSEXP_XPRTSEC_NONE = 0x01,
> > > + NFSEXP_XPRTSEC_TLS = 0x02,
> > > + NFSEXP_XPRTSEC_MTLS = 0x04,
> > > +};
> > > +
> > > +#define NFSEXP_XPRTSEC_ALL (NFSEXP_XPRTSEC_NONE | \
> > > + NFSEXP_XPRTSEC_TLS | \
> > > + NFSEXP_XPRTSEC_MTLS)
> > > +
> > > /* an "export key" (expkey) maps a filehandlefragement to an
> > > * svc_export for a given client. There can be several per export,
> > > * for the different fsid types.
> > >
> > >
> >
> > --
> > Jeff Layton <jlayton@xxxxxxxxxx>
> >
>
> --
> Chuck Lever
>
>
--
Jeff Layton <jlayton@xxxxxxxxxx>
