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).
> +
> + 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>
