Re: [PATCH Version 5 07/17] SUNRPC AUTH_GSS RPCSEC_GSS_CREATE with no payload

["J. Bruce Fields" <bfields@fieldses.org>]

On Fri, Feb 24, 2017 at 05:19:43PM -0500, andros@netapp.com wrote:
> From: Andy Adamson <andros@netapp.com>
> 
> Signed-off-by: Andy Adamson <andros@netapp.com>
> ---
>  include/linux/sunrpc/auth_gss.h |  54 ++++++++++++
>  net/sunrpc/auth_gss/auth_gss.c  | 182 ++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 236 insertions(+)
> 
> diff --git a/include/linux/sunrpc/auth_gss.h b/include/linux/sunrpc/auth_gss.h
> index 4ab63a9..b2a5a61 100644
> --- a/include/linux/sunrpc/auth_gss.h
> +++ b/include/linux/sunrpc/auth_gss.h
> @@ -93,6 +93,60 @@ struct gss_cred {
>  	unsigned long		gc_upcall_timestamp;
>  };
>  
> +/** GSS3 */
> +enum gss3_type {
> +	GSS3_LABEL = 0,
> +	GSS3_PRIVS = 1,
> +};
> +
> +struct gss3_chan_binding {
> +	u32	cb_len;
> +	void	*cb_binding;
> +};
> +
> +struct gss3_mp_auth {
> +	u32	mp_handle_len;
> +	void	*mp_handle;
> +	u32	*mp_mic_len;
> +	void	*mp_mic;	/* header mic */
> +};
> +
> +struct gss3_label {
> +	u32			la_lfs;
> +	u32			la_pi;
> +	struct xdr_netobj	la_label;
> +};
> +
> +struct gss3_privs {
> +	char	*pr_name;
> +	u32	pr_num;
> +	void	*pr_data;
> +};
> +
> +struct gss3_assertion_u {
> +	u32	au_type;
> +	union {
> +		struct gss3_label	au_label;
> +		struct gss3_privs	au_privs;
> +	} u;
> +};
> +
> +struct gss3_create_args {
> +	struct gss3_mp_auth		*ca_mp_auth;
> +	struct gss3_chan_binding	*ca_chan_bind;
> +	u32			ca_num;
> +	struct gss3_assertion_u	*ca_assertions;
> +};
> +
> +struct gss3_create_res {
> +	u32		cr_hlen;
> +	void		*cr_handle;
> +	struct gss3_mp_auth		*cr_mp_auth;
> +	struct gss3_chan_binding	*cr_chan_bind;
> +	u32			cr_num;
> +	struct gss3_assertion_u	*cr_assertions;
> +};
> +
>  #endif /* __KERNEL__ */
>  #endif /* _LINUX_SUNRPC_AUTH_GSS_H */
>  
> diff --git a/net/sunrpc/auth_gss/auth_gss.c b/net/sunrpc/auth_gss/auth_gss.c
> index 499cf99..6ffb16d 100644
> --- a/net/sunrpc/auth_gss/auth_gss.c
> +++ b/net/sunrpc/auth_gss/auth_gss.c
> @@ -1591,6 +1591,188 @@ static int gss_cred_is_negative_entry(struct rpc_cred *cred)
>  	return 0;
>  }
>  
> +/**
> + * GSS3_createargs_maxsz and GSS3_createres_maxsz
> + * include no rgss3_assertion_u payload.
> + */
> +#define GSS3_createargs_maxsz  (1 /* empty ca_mp_auth */ + \
> +				1 /* empty ca_chan_bind */ + \
> +				1 /* ca_num */ + \
> +				1 /* au_type */)
> +#define GSS3_createres_maxsz   (1 /* cr_hlen */ + \
> +				XDR_QUADLEN(1024) /* cr_handle*/ + \
> +				GSS3_createargs_maxsz)
> +
> +static void
> +gss3_enc_create(struct rpc_rqst *req, struct xdr_stream *xdr,
> +		const struct gss3_create_args *g3ca)
> +{
> +	u32 type;
> +	__be32 *p;
> +
> +	p = xdr_reserve_space(xdr, GSS3_createargs_maxsz << 2);
> +	*p++ = cpu_to_be32(0); /* NULL ca_mp_auth */
> +	*p++ = cpu_to_be32(0); /* NULL ca_chan_bind */
> +	*p++ = cpu_to_be32(g3ca->ca_num);
> +	type = cpu_to_be32(g3ca->ca_assertions->au_type);
> +	*p++ = type;
> +	switch (type) {
> +	case GSS3_LABEL:
> +	case GSS3_PRIVS:
> +	default:
> +		/* drop through to return */
> +		pr_warn("RPC    Unsupported gss3 create assertion %d\n", type);
> +	}
> +}
> +
> +static int
> +gss3_dec_create(struct rpc_rqst *req, struct xdr_stream *xdr,
> +		struct gss3_create_res *g3cr)
> +{
> +	u32 dummy, type;
> +	__be32 *p;
> +
> +	p = xdr_inline_decode(xdr, 4);
> +	if (unlikely(!p))
> +		goto out_overflow;
> +	g3cr->cr_hlen = be32_to_cpup(p++);
> +
> +	p = xdr_inline_decode(xdr, g3cr->cr_hlen + 16);
> +	if (unlikely(!p))
> +		goto out_overflow;
> +
> +	g3cr->cr_handle = kmemdup(p, g3cr->cr_hlen, GFP_KERNEL);
> +	if (!g3cr->cr_handle)
> +		goto out_err;
> +
> +	p += XDR_QUADLEN(g3cr->cr_hlen);
> +
> +	/* cr_mp_auth: not supported */
> +	dummy = be32_to_cpup(p++);
> +	if (dummy != 0) {
> +		pr_warn("RPC    gss3 create cr_mp_auth not supported\n");
> +		goto out_free_handle;
> +	}
> +
> +	/* cr_chan_bind: not supported */
> +	dummy = be32_to_cpup(p++);
> +	if (dummy != 0) {
> +		pr_warn("RPC    gss3 create cr_chan_bind not supported\n");
> +		goto out_free_handle;
> +	}
> +
> +	/* XXX Support one assertion */
> +	g3cr->cr_num = be32_to_cpup(p++);
> +	if (g3cr->cr_num != 1) {
> +		pr_warn("RPC    gss3 multiple assertions %d unspported\n",
> +			g3cr->cr_num);
> +		goto out_free_handle;
> +	}
> +
> +	/* au_type */
> +	type = be32_to_cpup(p++);
> +	switch (type) {
> +	case GSS3_LABEL:
> +	case GSS3_PRIVS:
> +	default:
> +		pr_warn("RPC    Unsupported gss3 create assertion %d\n", type);
> +		goto out_free_handle;
> +	}

It's a little confusing to have a decode routine that always fails;
maybe just squash this patch together with the following one?

--b.

> +	return 0;
> +
> +out_free_handle:
> +	kfree(g3cr->cr_handle);
> +out_err:
> +	return -EIO;
> +out_overflow:
> +	pr_warn("RPC    %s End of receive buffer. Remaining len: %tu words.\n",
> +		__func__, xdr->end - xdr->p);
> +	goto out_err;
> +}
> +
> +#define RPC_PROC_NULL 0
> +
> +struct rpc_procinfo gss3_label_assertion[] = {
> +	[RPC_GSS_PROC_CREATE] = {
> +		.p_proc		= RPC_PROC_NULL,
> +		.p_encode	= (kxdreproc_t)gss3_enc_create,
> +		.p_decode	= (kxdrdproc_t)gss3_dec_create,
> +		.p_arglen	= GSS3_createargs_maxsz,
> +		.p_replen	= GSS3_createres_maxsz,
> +		.p_statidx	= RPC_GSS_PROC_CREATE,
> +		.p_timer	= 0,
> +		.p_name		= "GSS_PROC_CREATE",
> +	},
> +};
> +
> +/**
> + * RPC_GSS_PROC_CREATE operation
> + *
> + * Notes:
> + *    1) Spec says we MUST use integrity or privacy security service.
> + *    First pass; use rpc_gss_svc_none.
> + *    2) asserts are allocated by caller, and freed here.
> + */
> +static int
> +gss3_proc_create(struct rpc_cred *cred, struct gss3_assertion_u *asserts,
> +		 int numasserts)
> +{
> +	struct gss_auth *gss_auth = container_of(cred->cr_auth, struct gss_auth,
> +						 rpc_auth);
> +	struct gss_cl_ctx *ctx = gss_cred_get_ctx(cred);
> +	struct rpc_task *task;
> +	struct gss3_create_res cres = {
> +		.cr_mp_auth = 0,
> +	};
> +	struct gss3_create_args *cargs = NULL;
> +	int ret = -EINVAL;
> +
> +	if (!ctx || !asserts)
> +		goto out;
> +	/**
> +	 * Take a reference to ensure the cred sticks around as we create
> +	 * a child context
> +	 * XXX does grabbing a reference to the context (gss_cred_get_ctx)
> +	 * also keep the cred from being removed?
> +	 * XXX do we need to keep this cred reference until the child context
> +	 * handle and associated assertion is removed?
> +	 */
> +	get_rpccred(cred);
> +
> +	ret = -ENOMEM;
> +	cargs = kzalloc(sizeof(*cargs), GFP_NOFS);
> +	if (!cargs)
> +		goto out_err;
> +
> +	cargs->ca_assertions = asserts;
> +	cargs->ca_num = numasserts;
> +	ctx->gc_proc = RPC_GSS_PROC_CREATE;
> +	cred->cr_ops = &gss_credops;
> +
> +	/* Want a sync rpc call */
> +	task = rpc_call_null_payload(gss_auth->client, cred, 0, cargs, &cres,
> +				    &gss3_label_assertion[RPC_GSS_PROC_CREATE]);
> +	if (IS_ERR(task)) {
> +		ret = PTR_ERR(task);
> +		goto out_free_assert;
> +	}
> +	if (task->tk_status != 0) {
> +		ret = task->tk_status;
> +		goto out_free_assert;
> +	}
> +	rpc_put_task(task);
> +
> +out_free_assert:
> +	kfree(cargs->ca_assertions);
> +	kfree(cargs);
> +out_err:
> +	ctx->gc_proc = RPC_GSS_PROC_DATA;
> +	gss_put_ctx(ctx);
> +	put_rpccred(cred);
> +out:
> +	return ret;
> +}
> +
>  /*
>  * Refresh credentials. XXX - finish
>  */
> -- 
> 2.9.3