[PATCH Version 3 07/16] SUNRPC AUTH_GSS RPCSEC_GSS_CREATE with label payload

From: <andros@netapp.com>
To: <anna.schumaker@netapp.com>
Cc: <bfieldses.org@netapp.com>, <linux-nfs@vger.kernel.org>,
	Andy Adamson <andros@netapp.com>
Subject: [PATCH Version 3 07/16] SUNRPC AUTH_GSS RPCSEC_GSS_CREATE with label payload
Date: Fri, 23 Dec 2016 11:04:19 -0500	[thread overview]
Message-ID: <1482509068-24516-8-git-send-email-andros@netapp.com> (raw)
In-Reply-To: <1482509068-24516-1-git-send-email-andros@netapp.com>

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  | 282 ++++++++++++++++++++++++++++++++++++++++
 2 files changed, 336 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 d11f421..e39c1af 100644
--- a/net/sunrpc/auth_gss/auth_gss.c
+++ b/net/sunrpc/auth_gss/auth_gss.c
@@ -52,9 +52,12 @@
 #include <linux/sunrpc/gss_api.h>
 #include <asm/uaccess.h>
 #include <linux/hashtable.h>
+#include <linux/security.h>
 
 #include "../netns.h"
 
+static int gss3_create_label(struct rpc_cred *cred);
+
 static const struct rpc_authops authgss_ops;
 
 static const struct rpc_credops gss_credops;
@@ -145,6 +148,8 @@ struct gss_auth {
 	set_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags);
 	smp_mb__before_atomic();
 	clear_bit(RPCAUTH_CRED_NEW, &cred->cr_flags);
+	/* XXXX make void? check retunr ?? */
+	gss3_create_label(cred);
 }
 
 static const void *
@@ -1591,6 +1596,283 @@ 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.
+ *
+ * GSS3_createargs_maxsz is currently for one label.
+ */
+#define GSS3_createargs_maxsz	(1 /* empty ca_mp_auth */ + \
+				 1 /* empty ca_chan_bind */ + \
+				 1 /* ca_num */ + \
+				 1 /* au_type */)
+#define GSS3_labelargs_maxsz	(1 /* la_lfs */ + \
+				 1 /* la_pi */ + \
+				 1 /* la_label.len */ + \
+				 XDR_QUADLEN(1024) /* la_label.data */)
+#define GSS3_createres_maxsz	(1 /* cr_hlen */ + \
+				 XDR_QUADLEN(1024) /* cr_handle*/ + \
+				 GSS3_createargs_maxsz)
+#define GSS3_labelres_maxsz	GSS3_labelargs_maxsz
+
+#define GSS3_listargs_maxsz	(1) /* dummy */
+#define GSS3_listres_maxsz	(1) /* dummy */
+
+static void
+gss3_enc_label(struct rpc_rqst *req, struct xdr_stream *xdr,
+	       const struct gss3_create_args *g3ca)
+{
+	struct gss3_label *gl;
+	__be32 *p;
+
+	gl = &g3ca->ca_assertions[0].u.au_label;
+
+	dprintk("RPC: %5u encoding GSSv3 label %s:%d\n", req->rq_task->tk_pid,
+		(char *)gl->la_label.data, gl->la_label.len);
+
+	p = xdr_reserve_space(xdr, GSS3_labelargs_maxsz << 2);
+	*p++ = cpu_to_be32(0); /* la_lfs */
+	*p++ = cpu_to_be32(0); /* la_pi */
+	p = xdr_encode_netobj(p, &gl->la_label);
+}
+
+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);
+	/* the payload is a gss3_label */
+	type = cpu_to_be32(g3ca->ca_assertions->au_type);
+	*p++ = type;
+	switch (type) {
+	case GSS3_LABEL:
+		gss3_enc_label(req, xdr, g3ca);
+		break;
+	case GSS3_PRIVS:
+	default:
+		/* drop through to return */
+		pr_warn("RPC    Unsupported gss3 create assertion %d\n", type);
+	}
+}
+
+static int
+gss3_dec_label(struct rpc_rqst *req, struct xdr_stream *xdr,
+	       struct gss3_create_res *g3cr)
+{
+	struct gss3_label *gl;
+	struct gss3_assertion_u *g3a;
+	__be32 *p;
+
+	g3a = kzalloc(sizeof(*g3a), GFP_KERNEL);
+	if (!g3a)
+		goto out_err;
+
+	g3a->au_type = GSS3_LABEL;
+	gl = &g3a->u.au_label;
+
+	p = xdr_inline_decode(xdr, 12);
+	if (unlikely(!p))
+		goto out_overflow;
+
+	gl->la_lfs = be32_to_cpup(p++);
+	gl->la_pi = be32_to_cpup(p++);
+	gl->la_label.len = be32_to_cpup(p++);
+
+	p = xdr_inline_decode(xdr, gl->la_label.len);
+	if (unlikely(!p))
+		goto out_overflow;
+
+	gl->la_label.data = kmemdup(p, gl->la_label.len, GFP_KERNEL);
+	if (!gl->la_label.data)
+		goto out_free_assert;
+	/**
+	 * Note: need to store the assertion with the child handle
+	 * in the gss context cache.
+	 */
+
+	g3cr->cr_assertions = g3a;
+
+	return 0;
+
+out_free_assert:
+	kfree(g3a);
+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_free_assert;
+}
+
+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;
+	}
+
+	/* Support one label 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:
+		if (gss3_dec_label(req, xdr, g3cr) != 0)
+			goto out_free_handle;
+		break;
+	case GSS3_PRIVS:
+	default:
+		pr_warn("RPC    Unsupported gss3 create assertion %d\n", type);
+		goto out_free_handle;
+	}
+	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 + GSS3_labelargs_maxsz,
+		.p_replen	= GSS3_createres_maxsz + GSS3_labelres_maxsz,
+		.p_statidx	= RPC_GSS_PROC_CREATE,
+		.p_timer	= 0,
+		.p_name		= "GSS_CREATE_LABEL",
+	},
+};
+
+/** GSSv3 RPC_GSS_PROC_CREATE operation
+ * Note: MUST use integrity or privacy security service.
+ *	First pass; use rpc_gss_svc_none.
+ *
+ * scontext: returned from security_sid_to_scontext(u32 sid, char **scontext)
+ */
+static int
+gss3_create_label(struct rpc_cred *cred)
+{
+	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;
+	struct gss3_label *gl;
+	int ret = -EINVAL;
+
+	if (!ctx)
+		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);
+
+	if (ctx->gc_v != RPC_GSS3_VERSION || !selinux_is_enabled())
+		goto out_err;
+
+	ret = -ENOMEM;
+	cargs = kzalloc(sizeof(*cargs), GFP_NOFS);
+	if (!cargs)
+		goto out_err;
+	cargs->ca_assertions = kzalloc(sizeof(*cargs->ca_assertions), GFP_NOFS);
+	if (!cargs->ca_assertions)
+		goto out_free_args;
+
+	/* NOTE: not setting la_lfs, la_pi. Do we even need them? */
+	cargs->ca_num = 1;
+	cargs->ca_assertions->au_type = GSS3_LABEL;
+	gl = &cargs->ca_assertions->u.au_label;
+
+	ret = security_current_sid_to_context((char **)&gl->la_label.data,
+					      &gl->la_label.len);
+
+	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);
+out_free_args:
+	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
 */
-- 
1.8.3.1

