> 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.
>> +
>> + 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
