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 <chuck.lever@xxxxxxxxxx>
---
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 88231c9..cdb0b41 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 58fda1c..6851da4 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 98950e5..aba7687 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 f529404..9b81be8 100644
--- a/net/sunrpc/auth.c
+++ b/net/sunrpc/auth.c
@@ -124,6 +124,41 @@ 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
* @size: size of "array"
diff --git a/net/sunrpc/auth_gss/auth_gss.c b/net/sunrpc/auth_gss/auth_gss.c
index 282dfb1..a742007 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 f0f4eee..4db66f5 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)
{
--
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