On Wed, Jan 30, 2013 at 02:34:30PM -0500, Chuck Lever wrote:
> Add an API similar to rpcauth_lookup_pseudoflavor(). The NFS server
> should not call GSS API functions directly without first pinning
> the GSS module.
>
> Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
> ---
>
> Bruce-
>
> Are you interested in taking something like this (untested) patch
> for 3.9? (This has pre-requisites I posted earlier this week).
OK. Let me know what you want me to do.
> Not sure what to do about svcauth_gss_flavor(), which has the same
> issue.
There's no risk of the gss module disappearing out from under us there:
it's a symbol exported from that module, so there's a static dependency
of the nfsd module on it.
--b.
>
>
> fs/nfsd/nfs4xdr.c | 18 ++++++++---------
> include/linux/sunrpc/auth.h | 2 ++
> include/linux/sunrpc/gss_api.h | 3 +++
> net/sunrpc/auth.c | 35 +++++++++++++++++++++++++++++++++
> net/sunrpc/auth_gss/auth_gss.c | 1 +
> net/sunrpc/auth_gss/gss_mech_switch.c | 31 +++++++++++++++++++++++++++++
> 6 files changed, 80 insertions(+), 10 deletions(-)
>
> diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
> index 0dc1158..f986209 100644
> --- a/fs/nfsd/nfs4xdr.c
> +++ b/fs/nfsd/nfs4xdr.c
> @@ -3129,8 +3129,7 @@ static __be32
> nfsd4_do_encode_secinfo(struct nfsd4_compoundres *resp,
> __be32 nfserr,struct svc_export *exp)
> {
> - int i = 0;
> - u32 nflavs;
> + u32 i, nflavs;
> struct exp_flavor_info *flavs;
> struct exp_flavor_info def_flavs[2];
> __be32 *p;
> @@ -3162,23 +3161,22 @@ nfsd4_do_encode_secinfo(struct nfsd4_compoundres *resp,
> ADJUST_ARGS();
> for (i = 0; i < nflavs; i++) {
> u32 flav = flavs[i].pseudoflavor;
> - struct gss_api_mech *gm = gss_mech_get_by_pseudoflavor(flav);
> + struct rpcsec_gss_info info;
>
> - if (gm) {
> + if (rpcauth_lookup_gss_info(flav, &info) == 0) {
> RESERVE_SPACE(4);
> WRITE32(RPC_AUTH_GSS);
> ADJUST_ARGS();
> - RESERVE_SPACE(4 + gm->gm_oid.len);
> - WRITE32(gm->gm_oid.len);
> - WRITEMEM(gm->gm_oid.data, gm->gm_oid.len);
> + RESERVE_SPACE(4 + info.oid.len);
> + WRITE32(info.oid.len);
> + WRITEMEM(info.oid.data, info.oid.len);
> ADJUST_ARGS();
> RESERVE_SPACE(4);
> - WRITE32(0); /* qop */
> + WRITE32(info.qop);
> ADJUST_ARGS();
> RESERVE_SPACE(4);
> - WRITE32(gss_pseudoflavor_to_service(gm, flav));
> + WRITE32(info.service);
> ADJUST_ARGS();
> - gss_mech_put(gm);
> } else {
> RESERVE_SPACE(4);
> WRITE32(flav);
> diff --git a/include/linux/sunrpc/auth.h b/include/linux/sunrpc/auth.h
> index b1a49a5..312684c 100644
> --- a/include/linux/sunrpc/auth.h
> +++ b/include/linux/sunrpc/auth.h
> @@ -105,6 +105,7 @@ struct rpc_authops {
> void (*pipes_destroy)(struct rpc_auth *);
> int (*list_pseudoflavors)(rpc_authflavor_t *, int);
> rpc_authflavor_t (*lookup_pseudoflavor)(struct rpcsec_gss_info *);
> + int (*lookup_gss_info)(rpc_authflavor_t, struct rpcsec_gss_info *);
> };
>
> struct rpc_credops {
> @@ -140,6 +141,7 @@ int rpcauth_unregister(const struct rpc_authops *);
> struct rpc_auth * rpcauth_create(rpc_authflavor_t, struct rpc_clnt *);
> void rpcauth_release(struct rpc_auth *);
> rpc_authflavor_t rpcauth_lookup_gss_pseudoflavor(struct rpcsec_gss_info *);
> +int rpcauth_lookup_gss_info(rpc_authflavor_t, struct rpcsec_gss_info *);
> int rpcauth_list_flavors(rpc_authflavor_t *, int);
> struct rpc_cred * rpcauth_lookup_credcache(struct rpc_auth *, struct auth_cred *, int);
> void rpcauth_init_cred(struct rpc_cred *, const struct auth_cred *, struct rpc_auth *, const struct rpc_credops *);
> diff --git a/include/linux/sunrpc/gss_api.h b/include/linux/sunrpc/gss_api.h
> index 6f40fd1..1293a7b 100644
> --- a/include/linux/sunrpc/gss_api.h
> +++ b/include/linux/sunrpc/gss_api.h
> @@ -133,6 +133,9 @@ void gss_mech_unregister(struct gss_api_mech *);
> /* Given a GSS security tuple, look up a pseudoflavor */
> rpc_authflavor_t gss_mech_lookup_pseudoflavor(struct rpcsec_gss_info *);
>
> +/* Given a pseudoflavor, look up a GSS security tuple */
> +int gss_mech_lookup_info(rpc_authflavor_t, struct rpcsec_gss_info *);
> +
> /* Returns a reference to a mechanism, given a name like "krb5" etc. */
> struct gss_api_mech *gss_mech_get_by_name(const char *);
>
> diff --git a/net/sunrpc/auth.c b/net/sunrpc/auth.c
> index 32e305b..0cfffbc 100644
> --- a/net/sunrpc/auth.c
> +++ b/net/sunrpc/auth.c
> @@ -157,6 +157,41 @@ rpcauth_lookup_gss_pseudoflavor(struct rpcsec_gss_info *info)
> EXPORT_SYMBOL_GPL(rpcauth_lookup_gss_pseudoflavor);
>
> /**
> + * rpcauth_lookup_gss_info - find GSS tuple matching a pseudoflavor
> + * @pseudoflavor: GSS pseudoflavor to match
> + * @info: rpcsec_gss_info structure to fill in
> + *
> + * Returns zero and fills in "info" if pseudoflavor matches a
> + * supported mechanism.
> + */
> +int
> +rpcauth_lookup_gss_info(rpc_authflavor_t pseudoflavor, struct rpcsec_gss_info *info)
> +{
> + const struct rpc_authops *ops;
> + int result;
> +
> + if ((ops = auth_flavors[pseudoflavor]) == NULL)
> + request_module("rpc-auth-%u", RPC_AUTH_GSS);
> + spin_lock(&rpc_authflavor_lock);
> + ops = auth_flavors[pseudoflavor];
> + if (ops == NULL || !try_module_get(ops->owner)) {
> + spin_unlock(&rpc_authflavor_lock);
> + dprintk("RPC: %s: failed to pin module\n", __func__);
> + return -ENOMEM;
> + }
> + spin_unlock(&rpc_authflavor_lock);
> +
> + if (ops->lookup_gss_info == NULL)
> + result = -ENOMEM;
> + else
> + result = ops->lookup_gss_info(pseudoflavor, info);
> +
> + module_put(ops->owner);
> + return result;
> +}
> +EXPORT_SYMBOL_GPL(rpcauth_lookup_gss_info);
> +
> +/**
> * rpcauth_list_flavors - discover registered flavors and pseudoflavors
> * @array: array to fill in
> * @size: size of "array"
> diff --git a/net/sunrpc/auth_gss/auth_gss.c b/net/sunrpc/auth_gss/auth_gss.c
> index f2e8f45..f1e92f4 100644
> --- a/net/sunrpc/auth_gss/auth_gss.c
> +++ b/net/sunrpc/auth_gss/auth_gss.c
> @@ -1630,6 +1630,7 @@ static const struct rpc_authops authgss_ops = {
> .pipes_destroy = gss_pipes_dentries_destroy,
> .list_pseudoflavors = gss_mech_list_pseudoflavors,
> .lookup_pseudoflavor = gss_mech_lookup_pseudoflavor,
> + .lookup_gss_info = gss_mech_lookup_info,
> };
>
> static const struct rpc_credops gss_credops = {
> diff --git a/net/sunrpc/auth_gss/gss_mech_switch.c b/net/sunrpc/auth_gss/gss_mech_switch.c
> index 3ba0450..7331b0b 100644
> --- a/net/sunrpc/auth_gss/gss_mech_switch.c
> +++ b/net/sunrpc/auth_gss/gss_mech_switch.c
> @@ -314,6 +314,37 @@ rpc_authflavor_t gss_mech_lookup_pseudoflavor(struct rpcsec_gss_info *info)
> return pseudoflavor;
> }
>
> +/**
> + * gss_mech_lookup_info - look up a GSS tuple for a given pseudoflavor
> + * @pseudoflavor: GSS pseudoflavor to match
> + * @info: rpcsec_gss_info structure to fill in
> + *
> + * Returns zero and fills in "info" if pseudoflavor matches a
> + * supported mechanism.
> + */
> +int gss_mech_lookup_info(rpc_authflavor_t pseudoflavor, struct rpcsec_gss_info *info)
> +{
> + struct gss_api_mech *gm;
> + int i;
> +
> + gm = gss_mech_get_by_pseudoflavor(pseudoflavor);
> + if (gm == NULL)
> + return -ENOMEM;
> +
> + for (i = 0; i < gm->gm_pf_num; i++)
> + if (gm->gm_pfs[i].pseudoflavor == pseudoflavor) {
> + memcpy(info->oid.data, gm->gm_oid.data, gm->gm_oid.len);
> + info->oid.len = gm->gm_oid.len;
> + info->qop = gm->gm_pfs[i].qop;
> + info->service = gm->gm_pfs[i].service;
> + gss_mech_put(gm);
> + return 0;
> + }
> +
> + gss_mech_put(gm);
> + return -ENOMEM;
> +}
> +
> u32
> gss_pseudoflavor_to_service(struct gss_api_mech *gm, u32 pseudoflavor)
> {
>
> --
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