nfsd4: implement minimal SP4_MACH_CRED

Do a minimal SP4_MACH_CRED implementation suggested by Trond, ignoring
the client-provided spo_must_* arrays and just enforcing credential
checks for the minimum required operations.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 109b434..2383d24 100644 (file)
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -1265,6 +1265,31 @@ same_creds(struct svc_cred *cr1, struct svc_cred *cr2)
        return 0 == strcmp(cr1->cr_principal, cr2->cr_principal);
 }
 
+static bool svc_rqst_integrity_protected(struct svc_rqst *rqstp)
+{
+       struct svc_cred *cr = &rqstp->rq_cred;
+       u32 service;
+
+       service = gss_pseudoflavor_to_service(cr->cr_gss_mech, cr->cr_flavor);
+       return service == RPC_GSS_SVC_INTEGRITY ||
+              service == RPC_GSS_SVC_PRIVACY;
+}
+
+static bool mach_creds_match(struct nfs4_client *cl, struct svc_rqst *rqstp)
+{
+       struct svc_cred *cr = &rqstp->rq_cred;
+
+       if (!cl->cl_mach_cred)
+               return true;
+       if (cl->cl_cred.cr_gss_mech != cr->cr_gss_mech)
+               return false;
+       if (!svc_rqst_integrity_protected(rqstp))
+               return false;
+       if (!cr->cr_principal)
+               return false;
+       return 0 == strcmp(cl->cl_cred.cr_principal, cr->cr_principal);
+}
+
 static void gen_clid(struct nfs4_client *clp, struct nfsd_net *nn)
 {
        static u32 current_clientid = 1;
@@ -1642,16 +1667,16 @@ nfsd4_exchange_id(struct svc_rqst *rqstp,
        if (exid->flags & ~EXCHGID4_FLAG_MASK_A)
                return nfserr_inval;
 
-       /* Currently only support SP4_NONE */
        switch (exid->spa_how) {
+       case SP4_MACH_CRED:
+               if (!svc_rqst_integrity_protected(rqstp))
+                       return nfserr_inval;
        case SP4_NONE:
                break;
        default:                                /* checked by xdr code */
                WARN_ON_ONCE(1);
        case SP4_SSV:
                return nfserr_encr_alg_unsupp;
-       case SP4_MACH_CRED:
-               return nfserr_serverfault;      /* no excuse :-/ */
        }
 
        /* Cases below refer to rfc 5661 section 18.35.4: */
@@ -1666,6 +1691,10 @@ nfsd4_exchange_id(struct svc_rqst *rqstp,
                                status = nfserr_inval;
                                goto out;
                        }
+                       if (!mach_creds_match(conf, rqstp)) {
+                               status = nfserr_wrong_cred;
+                               goto out;
+                       }
                        if (!creds_match) { /* case 9 */
                                status = nfserr_perm;
                                goto out;
@@ -1713,6 +1742,7 @@ out_new:
                goto out;
        }
        new->cl_minorversion = cstate->minorversion;
+       new->cl_mach_cred = (exid->spa_how == SP4_MACH_CRED);
 
        gen_clid(new, nn);
        add_to_unconfirmed(new);
@@ -1877,6 +1907,9 @@ nfsd4_create_session(struct svc_rqst *rqstp,
        WARN_ON_ONCE(conf && unconf);
 
        if (conf) {
+               status = nfserr_wrong_cred;
+               if (!mach_creds_match(conf, rqstp))
+                       goto out_free_conn;
                cs_slot = &conf->cl_cs_slot;
                status = check_slot_seqid(cr_ses->seqid, cs_slot->sl_seqid, 0);
                if (status == nfserr_replay_cache) {
@@ -1893,6 +1926,9 @@ nfsd4_create_session(struct svc_rqst *rqstp,
                        status = nfserr_clid_inuse;
                        goto out_free_conn;
                }
+               status = nfserr_wrong_cred;
+               if (!mach_creds_match(unconf, rqstp))
+                       goto out_free_conn;
                cs_slot = &unconf->cl_cs_slot;
                status = check_slot_seqid(cr_ses->seqid, cs_slot->sl_seqid, 0);
                if (status) {
@@ -1989,6 +2025,9 @@ __be32 nfsd4_bind_conn_to_session(struct svc_rqst *rqstp,
        status = nfserr_badsession;
        if (!session)
                goto out;
+       status = nfserr_wrong_cred;
+       if (!mach_creds_match(session->se_client, rqstp))
+               goto out;
        status = nfsd4_map_bcts_dir(&bcts->dir);
        if (status)
                goto out;
@@ -2031,6 +2070,9 @@ nfsd4_destroy_session(struct svc_rqst *r,
        status = nfserr_badsession;
        if (!ses)
                goto out_client_lock;
+       status = nfserr_wrong_cred;
+       if (!mach_creds_match(ses->se_client, r))
+               goto out_client_lock;
        status = mark_session_dead_locked(ses);
        if (status)
                goto out_client_lock;
@@ -2061,26 +2103,31 @@ static struct nfsd4_conn *__nfsd4_find_conn(struct svc_xprt *xpt, struct nfsd4_s
        return NULL;
 }
 
-static void nfsd4_sequence_check_conn(struct nfsd4_conn *new, struct nfsd4_session *ses)
+static __be32 nfsd4_sequence_check_conn(struct nfsd4_conn *new, struct nfsd4_session *ses)
 {
        struct nfs4_client *clp = ses->se_client;
        struct nfsd4_conn *c;
+       __be32 status = nfs_ok;
        int ret;
 
        spin_lock(&clp->cl_lock);
        c = __nfsd4_find_conn(new->cn_xprt, ses);
-       if (c) {
-               spin_unlock(&clp->cl_lock);
-               free_conn(new);
-               return;
-       }
+       if (c)
+               goto out_free;
+       status = nfserr_conn_not_bound_to_session;
+       if (clp->cl_mach_cred)
+               goto out_free;
        __nfsd4_hash_conn(new, ses);
        spin_unlock(&clp->cl_lock);
        ret = nfsd4_register_conn(new);
        if (ret)
                /* oops; xprt is already down: */
                nfsd4_conn_lost(&new->cn_xpt_user);
-       return;
+       return nfs_ok;
+out_free:
+       spin_unlock(&clp->cl_lock);
+       free_conn(new);
+       return status;
 }
 
 static bool nfsd4_session_too_many_ops(struct svc_rqst *rqstp, struct nfsd4_session *session)
@@ -2172,8 +2219,10 @@ nfsd4_sequence(struct svc_rqst *rqstp,
        if (status)
                goto out_put_session;
 
-       nfsd4_sequence_check_conn(conn, session);
+       status = nfsd4_sequence_check_conn(conn, session);
        conn = NULL;
+       if (status)
+               goto out_put_session;
 
        /* Success! bump slot seqid */
        slot->sl_seqid = seq->seqid;
@@ -2235,7 +2284,10 @@ nfsd4_destroy_clientid(struct svc_rqst *rqstp, struct nfsd4_compound_state *csta
                status = nfserr_stale_clientid;
                goto out;
        }
-
+       if (!mach_creds_match(clp, rqstp)) {
+               status = nfserr_wrong_cred;
+               goto out;
+       }
        expire_client(clp);
 out:
        nfs4_unlock_state();

diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index 170ea7e..3126210 100644 (file)
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -3321,6 +3321,14 @@ nfsd4_encode_write(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_w
        return nfserr;
 }
 
+static const u32 nfs4_minimal_spo_must_enforce[2] = {
+       [1] = 1 << (OP_BIND_CONN_TO_SESSION - 32) |
+             1 << (OP_EXCHANGE_ID - 32) |
+             1 << (OP_CREATE_SESSION - 32) |
+             1 << (OP_DESTROY_SESSION - 32) |
+             1 << (OP_DESTROY_CLIENTID - 32)
+};
+
 static __be32
 nfsd4_encode_exchange_id(struct nfsd4_compoundres *resp, __be32 nfserr,
                         struct nfsd4_exchange_id *exid)
@@ -3359,6 +3367,20 @@ nfsd4_encode_exchange_id(struct nfsd4_compoundres *resp, __be32 nfserr,
        /* state_protect4_r. Currently only support SP4_NONE */
        BUG_ON(exid->spa_how != SP4_NONE);
        WRITE32(exid->spa_how);
+       switch (exid->spa_how) {
+       case SP4_NONE:
+               break;
+       case SP4_MACH_CRED:
+               /* spo_must_enforce bitmap: */
+               WRITE32(2);
+               WRITE32(nfs4_minimal_spo_must_enforce[0]);
+               WRITE32(nfs4_minimal_spo_must_enforce[1]);
+               /* empty spo_must_allow bitmap: */
+               WRITE32(0);
+               break;
+       default:
+               WARN_ON_ONCE(1);
+       }
 
        /* The server_owner struct */
        WRITE64(minor_id);      /* Minor id */

diff --git a/fs/nfsd/state.h b/fs/nfsd/state.h
index 274e2a1..424d8f5 100644 (file)
--- a/fs/nfsd/state.h
+++ b/fs/nfsd/state.h
@@ -246,6 +246,7 @@ struct nfs4_client {
        nfs4_verifier           cl_verifier;    /* generated by client */
        time_t                  cl_time;        /* time of last lease renewal */
        struct sockaddr_storage cl_addr;        /* client ipaddress */
+       bool                    cl_mach_cred;   /* SP4_MACH_CRED in force */
        struct svc_cred         cl_cred;        /* setclientid principal */
        clientid_t              cl_clientid;    /* generated by server */
        nfs4_verifier           cl_confirm;     /* generated by server */