data->mount_server.port = NFS_UNSPEC_PORT;
data->nfs_server.port = NFS_UNSPEC_PORT;
data->nfs_server.protocol = XPRT_TRANSPORT_TCP;
- data->auth_flavors[0] = RPC_AUTH_UNIX;
+ data->auth_flavors[0] = RPC_AUTH_MAXFLAVOR;
data->auth_flavor_len = 1;
data->minorversion = 0;
data->need_mount = true;
}
/*
- * Match the requested auth flavors with the list returned by
- * the server. Returns zero and sets the mount's authentication
- * flavor on success; returns -EACCES if server does not support
- * the requested flavor.
+ * Select a security flavor for this mount. The selected flavor
+ * is planted in args->auth_flavors[0].
+ *
+ * Returns 0 on success, -EACCES on failure.
*/
-static int nfs_walk_authlist(struct nfs_parsed_mount_data *args,
- struct nfs_mount_request *request)
+static int nfs_select_flavor(struct nfs_parsed_mount_data *args,
+ struct nfs_mount_request *request)
{
- unsigned int i, j, server_authlist_len = *(request->auth_flav_len);
+ unsigned int i, count = *(request->auth_flav_len);
+ rpc_authflavor_t flavor;
+
+ /*
+ * The NFSv2 MNT operation does not return a flavor list.
+ */
+ if (args->mount_server.version != NFS_MNT3_VERSION)
+ goto out_default;
/*
* Certain releases of Linux's mountd return an empty
- * flavor list. To prevent behavioral regression with
- * these servers (ie. rejecting mounts that used to
- * succeed), revert to pre-2.6.32 behavior (no checking)
- * if the returned flavor list is empty.
+ * flavor list in some cases.
*/
- if (server_authlist_len == 0)
- return 0;
+ if (count == 0)
+ goto out_default;
/*
- * We avoid sophisticated negotiating here, as there are
- * plenty of cases where we can get it wrong, providing
- * either too little or too much security.
+ * If the sec= mount option is used, the specified flavor or AUTH_NULL
+ * must be in the list returned by the server.
*
+ * AUTH_NULL has a special meaning when it's in the server list - it
+ * means that the server will ignore the rpc creds, so any flavor
+ * can be used.
+ */
+ if (args->auth_flavors[0] != RPC_AUTH_MAXFLAVOR) {
+ for (i = 0; i < count; i++) {
+ if (args->auth_flavors[0] == request->auth_flavs[i] ||
+ request->auth_flavs[i] == RPC_AUTH_NULL)
+ goto out;
+ }
+ dfprintk(MOUNT, "NFS: auth flavor %d not supported by server\n",
+ args->auth_flavors[0]);
+ goto out_err;
+ }
+
+ /*
* RFC 2623, section 2.7 suggests we SHOULD prefer the
* flavor listed first. However, some servers list
- * AUTH_NULL first. Our caller plants AUTH_SYS, the
- * preferred default, in args->auth_flavors[0] if user
- * didn't specify sec= mount option.
+ * AUTH_NULL first. Avoid ever choosing AUTH_NULL.
*/
- for (i = 0; i < args->auth_flavor_len; i++)
- for (j = 0; j < server_authlist_len; j++)
- if (args->auth_flavors[i] == request->auth_flavs[j]) {
- dfprintk(MOUNT, "NFS: using auth flavor %d\n",
- request->auth_flavs[j]);
- args->auth_flavors[0] = request->auth_flavs[j];
- return 0;
- }
+ for (i = 0; i < count; i++) {
+ struct rpcsec_gss_info info;
+
+ flavor = request->auth_flavs[i];
+ switch (flavor) {
+ case RPC_AUTH_UNIX:
+ goto out_set;
+ case RPC_AUTH_NULL:
+ continue;
+ default:
+ if (rpcauth_get_gssinfo(flavor, &info) == 0)
+ goto out_set;
+ }
+ }
+
+ /*
+ * As a last chance, see if the server list contains AUTH_NULL -
+ * if it does, use the default flavor.
+ */
+ for (i = 0; i < count; i++) {
+ if (request->auth_flavs[i] == RPC_AUTH_NULL)
+ goto out_default;
+ }
+
+ dfprintk(MOUNT, "NFS: no auth flavors in common with server\n");
+ goto out_err;
- dfprintk(MOUNT, "NFS: server does not support requested auth flavor\n");
- nfs_umount(request);
+out_default:
+ /* use default if flavor not already set */
+ flavor = (args->auth_flavors[0] == RPC_AUTH_MAXFLAVOR) ?
+ RPC_AUTH_UNIX : args->auth_flavors[0];
+out_set:
+ args->auth_flavors[0] = flavor;
+out:
+ dfprintk(MOUNT, "NFS: using auth flavor %d\n", args->auth_flavors[0]);
+ return 0;
+out_err:
return -EACCES;
}
return status;
}
- /*
- * MNTv1 (NFSv2) does not support auth flavor negotiation.
- */
- if (args->mount_server.version != NFS_MNT3_VERSION)
- return 0;
- return nfs_walk_authlist(args, &request);
+ return nfs_select_flavor(args, &request);
}
struct dentry *nfs_try_mount(int flags, const char *dev_name,
struct nfs_mount_info *mount_info)
{
/* clone any lsm security options from the parent to the new sb */
- security_sb_clone_mnt_opts(mount_info->cloned->sb, s);
if (mntroot->d_inode->i_op != NFS_SB(s)->nfs_client->rpc_ops->dir_inode_ops)
return -ESTALE;
- return 0;
+ return security_sb_clone_mnt_opts(mount_info->cloned->sb, s);
}
EXPORT_SYMBOL_GPL(nfs_clone_sb_security);
projects / ~andy / linux / blobdiff