From 9568c5e9a61de49f67f524404a27a1014a8d7f1e Mon Sep 17 00:00:00 2001 From: Chuck Lever Date: Sat, 16 Mar 2013 15:54:43 -0400 Subject: [PATCH] SUNRPC: Introduce rpcauth_get_pseudoflavor() A SECINFO reply may contain flavors whose kernel module is not yet loaded by the client's kernel. A new RPC client API, called rpcauth_get_pseudoflavor(), is introduced to do proper checking for support of a security flavor. When this API is invoked, the RPC client now tries to load the module for each flavor first before performing the "is this supported?" check. This means if a module is available on the client, but has not been loaded yet, it will be loaded and registered automatically when the SECINFO reply is processed. The new API can take a full GSS tuple (OID, QoP, and service). Previously only the OID and service were considered. nfs_find_best_sec() is updated to verify all flavors requested in a SECINFO reply, including AUTH_NULL and AUTH_UNIX. Previously these two flavors were simply assumed to be supported without consulting the RPC client. Note that the replaced version of nfs_find_best_sec() can return RPC_AUTH_MAXFLAVOR if the server returns a recognized OID but an unsupported "service" value. nfs_find_best_sec() now returns RPC_AUTH_UNIX in this case. Signed-off-by: Chuck Lever Signed-off-by: Trond Myklebust --- fs/nfs/nfs4namespace.c | 41 +++++++++++++++------------ include/linux/sunrpc/auth.h | 5 ++++ include/linux/sunrpc/gss_api.h | 5 ++-- net/sunrpc/auth.c | 35 +++++++++++++++++++++++ net/sunrpc/auth_gss/auth_gss.c | 1 + net/sunrpc/auth_gss/gss_mech_switch.c | 28 ++++++++++++++---- 6 files changed, 89 insertions(+), 26 deletions(-) diff --git a/fs/nfs/nfs4namespace.c b/fs/nfs/nfs4namespace.c index 88231c92317c..cdb0b41a4810 100644 --- a/fs/nfs/nfs4namespace.c +++ b/fs/nfs/nfs4namespace.c @@ -134,33 +134,38 @@ static size_t nfs_parse_server_name(char *string, size_t len, return ret; } +/** + * nfs_find_best_sec - Find a security mechanism supported locally + * @flavors: List of security tuples returned by SECINFO procedure + * + * Return the pseudoflavor of the first security mechanism in + * "flavors" that is locally supported. Return RPC_AUTH_UNIX if + * no matching flavor is found in the array. The "flavors" array + * is searched in the order returned from the server, per RFC 3530 + * recommendation. + */ rpc_authflavor_t nfs_find_best_sec(struct nfs4_secinfo_flavors *flavors) { - struct gss_api_mech *mech; - struct xdr_netobj oid; + rpc_authflavor_t pseudoflavor; + struct nfs4_secinfo4 *secinfo; unsigned int i; - rpc_authflavor_t pseudoflavor = RPC_AUTH_UNIX; for (i = 0; i < flavors->num_flavors; i++) { - struct nfs4_secinfo4 *flavor = &flavors->flavors[i]; - - if (flavor->flavor == RPC_AUTH_NULL || flavor->flavor == RPC_AUTH_UNIX) { - pseudoflavor = flavor->flavor; - break; - } else if (flavor->flavor == RPC_AUTH_GSS) { - oid.len = flavor->flavor_info.oid.len; - oid.data = flavor->flavor_info.oid.data; - mech = gss_mech_get_by_OID(&oid); - if (!mech) - continue; - pseudoflavor = gss_svc_to_pseudoflavor(mech, - flavor->flavor_info.service); - gss_mech_put(mech); + secinfo = &flavors->flavors[i]; + + switch (secinfo->flavor) { + case RPC_AUTH_NULL: + case RPC_AUTH_UNIX: + case RPC_AUTH_GSS: + pseudoflavor = rpcauth_get_pseudoflavor(secinfo->flavor, + &secinfo->flavor_info); + if (pseudoflavor != RPC_AUTH_MAXFLAVOR) + return pseudoflavor; break; } } - return pseudoflavor; + return RPC_AUTH_UNIX; } static rpc_authflavor_t nfs4_negotiate_security(struct inode *inode, struct qstr *name) diff --git a/include/linux/sunrpc/auth.h b/include/linux/sunrpc/auth.h index 58fda1c3c783..6851da4cb416 100644 --- a/include/linux/sunrpc/auth.h +++ b/include/linux/sunrpc/auth.h @@ -22,6 +22,8 @@ /* size of the nodename buffer */ #define UNX_MAXNODENAME 32 +struct rpcsec_gss_info; + /* Work around the lack of a VFS credential */ struct auth_cred { kuid_t uid; @@ -103,6 +105,7 @@ struct rpc_authops { int (*pipes_create)(struct rpc_auth *); void (*pipes_destroy)(struct rpc_auth *); int (*list_pseudoflavors)(rpc_authflavor_t *, int); + rpc_authflavor_t (*info2flavor)(struct rpcsec_gss_info *); }; struct rpc_credops { @@ -137,6 +140,8 @@ int rpcauth_register(const struct rpc_authops *); 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_get_pseudoflavor(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 98950e5a8877..aba7687ca884 100644 --- a/include/linux/sunrpc/gss_api.h +++ b/include/linux/sunrpc/gss_api.h @@ -127,9 +127,8 @@ struct gss_api_ops { int gss_mech_register(struct gss_api_mech *); void gss_mech_unregister(struct gss_api_mech *); -/* returns a mechanism descriptor given an OID, and increments the mechanism's - * reference count. */ -struct gss_api_mech * gss_mech_get_by_OID(struct xdr_netobj *); +/* Given a GSS security tuple, look up a pseudoflavor */ +rpc_authflavor_t gss_mech_info2flavor(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 f5294047df77..9b81be8d9946 100644 --- a/net/sunrpc/auth.c +++ b/net/sunrpc/auth.c @@ -123,6 +123,41 @@ rpcauth_unregister(const struct rpc_authops *ops) } EXPORT_SYMBOL_GPL(rpcauth_unregister); +/** + * rpcauth_get_pseudoflavor - check if security flavor is supported + * @flavor: a security flavor + * @info: a GSS mech OID, quality of protection, and service value + * + * Verifies that an appropriate kernel module is available or already loaded. + * Returns an equivalent pseudoflavor, or RPC_AUTH_MAXFLAVOR if "flavor" is + * not supported locally. + */ +rpc_authflavor_t +rpcauth_get_pseudoflavor(rpc_authflavor_t flavor, struct rpcsec_gss_info *info) +{ + const struct rpc_authops *ops; + rpc_authflavor_t pseudoflavor; + + ops = auth_flavors[flavor]; + if (ops == NULL) + request_module("rpc-auth-%u", flavor); + spin_lock(&rpc_authflavor_lock); + ops = auth_flavors[flavor]; + if (ops == NULL || !try_module_get(ops->owner)) { + spin_unlock(&rpc_authflavor_lock); + return RPC_AUTH_MAXFLAVOR; + } + spin_unlock(&rpc_authflavor_lock); + + pseudoflavor = flavor; + if (ops->info2flavor != NULL) + pseudoflavor = ops->info2flavor(info); + + module_put(ops->owner); + return pseudoflavor; +} +EXPORT_SYMBOL_GPL(rpcauth_get_pseudoflavor); + /** * rpcauth_list_flavors - discover registered flavors and pseudoflavors * @array: array to fill in diff --git a/net/sunrpc/auth_gss/auth_gss.c b/net/sunrpc/auth_gss/auth_gss.c index 282dfb14db05..a7420076ef39 100644 --- a/net/sunrpc/auth_gss/auth_gss.c +++ b/net/sunrpc/auth_gss/auth_gss.c @@ -1641,6 +1641,7 @@ static const struct rpc_authops authgss_ops = { .pipes_create = gss_pipes_dentries_create, .pipes_destroy = gss_pipes_dentries_destroy, .list_pseudoflavors = gss_mech_list_pseudoflavors, + .info2flavor = gss_mech_info2flavor, }; 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 f0f4eee63a35..4db66f5f490e 100644 --- a/net/sunrpc/auth_gss/gss_mech_switch.c +++ b/net/sunrpc/auth_gss/gss_mech_switch.c @@ -171,8 +171,7 @@ struct gss_api_mech * gss_mech_get_by_name(const char *name) } EXPORT_SYMBOL_GPL(gss_mech_get_by_name); -struct gss_api_mech * -gss_mech_get_by_OID(struct xdr_netobj *obj) +static struct gss_api_mech *gss_mech_get_by_OID(struct rpcsec_gss_oid *obj) { struct gss_api_mech *pos, *gm = NULL; @@ -188,11 +187,8 @@ gss_mech_get_by_OID(struct xdr_netobj *obj) } spin_unlock(®istered_mechs_lock); return gm; - } -EXPORT_SYMBOL_GPL(gss_mech_get_by_OID); - static inline int mech_supports_pseudoflavor(struct gss_api_mech *gm, u32 pseudoflavor) { @@ -282,6 +278,28 @@ gss_svc_to_pseudoflavor(struct gss_api_mech *gm, u32 service) } EXPORT_SYMBOL_GPL(gss_svc_to_pseudoflavor); +/** + * gss_mech_info2flavor - look up a pseudoflavor given a GSS tuple + * @info: a GSS mech OID, quality of protection, and service value + * + * Returns a matching pseudoflavor, or RPC_AUTH_MAXFLAVOR if the tuple is + * not supported. + */ +rpc_authflavor_t gss_mech_info2flavor(struct rpcsec_gss_info *info) +{ + rpc_authflavor_t pseudoflavor; + struct gss_api_mech *gm; + + gm = gss_mech_get_by_OID(&info->oid); + if (gm == NULL) + return RPC_AUTH_MAXFLAVOR; + + pseudoflavor = gss_svc_to_pseudoflavor(gm, info->service); + + gss_mech_put(gm); + return pseudoflavor; +} + u32 gss_pseudoflavor_to_service(struct gss_api_mech *gm, u32 pseudoflavor) { -- 2.20.1