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nfsd4: implement minimal SP4_MACH_CRED
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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>
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J. Bruce Fields committed Jul 1, 2013
1 parent 0dc1531 commit 57266a6
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Showing 3 changed files with 87 additions and 12 deletions.
76 changes: 64 additions & 12 deletions fs/nfsd/nfs4state.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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;
Expand Down Expand Up @@ -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: */
Expand All @@ -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;
Expand Down Expand Up @@ -1713,6 +1742,7 @@ nfsd4_exchange_id(struct svc_rqst *rqstp,
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);
Expand Down Expand Up @@ -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) {
Expand All @@ -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) {
Expand Down Expand Up @@ -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;
Expand Down Expand Up @@ -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;
Expand Down Expand Up @@ -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)
Expand Down Expand Up @@ -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;
Expand Down Expand Up @@ -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();
Expand Down
22 changes: 22 additions & 0 deletions fs/nfsd/nfs4xdr.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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)
Expand Down Expand Up @@ -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 */
Expand Down
1 change: 1 addition & 0 deletions fs/nfsd/state.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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 */
Expand Down

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