/*
  svc_in_gssd_proc.c

  Copyright (c) 2000 The Regents of the University of Michigan.
  All rights reserved.

  Copyright (c) 2002 Bruce Fields <bfields@UMICH.EDU>

  Redistribution and use in source and binary forms, with or without
  modification, are permitted provided that the following conditions
  are met:

  1. Redistributions of source code must retain the above copyright
     notice, this list of conditions and the following disclaimer.
  2. Redistributions in binary form must reproduce the above copyright
     notice, this list of conditions and the following disclaimer in the
     documentation and/or other materials provided with the distribution.
  3. Neither the name of the University nor the names of its
     contributors may be used to endorse or promote products derived
     from this software without specific prior written permission.

  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
  LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

*/

#include <sys/param.h>
#include <sys/stat.h>
#include <rpc/rpc.h>

#include <pwd.h>
#include <stdio.h>
#include <unistd.h>
#include <ctype.h>
#include <string.h>
#include <fcntl.h>
#include <errno.h>
#include <nfsidmap.h>

#include "svcgssd.h"
#include "gss_util.h"
#include "err_util.h"
#include "context.h"
#include "cacheio.h"

extern char * mech2file(gss_OID mech);
#define SVCGSSD_CONTEXT_CHANNEL "/proc/net/rpc/auth.rpcsec.context/channel"
#define SVCGSSD_INIT_CHANNEL    "/proc/net/rpc/auth.rpcsec.init/channel"

struct svc_cred {
	uid_t	cr_uid;
	gid_t	cr_gid;
	int	cr_ngroups;
	gid_t	cr_groups[NGROUPS];
};

static int
do_svc_downcall(gss_buffer_desc *out_handle, struct svc_cred *cred,
		gss_OID mech, gss_buffer_desc *context_token)
{
	FILE *f;
	int i;
	char *fname = NULL;

	printerr(1, "doing downcall\n");
	if ((fname = mech2file(mech)) == NULL)
		goto out_err;
	f = fopen(SVCGSSD_CONTEXT_CHANNEL, "w");
	if (f == NULL) {
		printerr(0, "WARNING: unable to open downcall channel "
			     "%s: %s\n",
			     SVCGSSD_CONTEXT_CHANNEL, strerror(errno));
		goto out_err;
	}
	qword_printhex(f, out_handle->value, out_handle->length);
	/* XXX are types OK for the rest of this? */
	qword_printint(f, 0x7fffffff); /*XXX need a better timeout */
	qword_printint(f, cred->cr_uid);
	qword_printint(f, cred->cr_gid);
	qword_printint(f, cred->cr_ngroups);
	for (i=0; i < cred->cr_ngroups; i++)
		qword_printint(f, cred->cr_groups[i]);
	qword_print(f, fname);
	qword_printhex(f, context_token->value, context_token->length);
	qword_eol(f);
	fclose(f);
	return 0;
out_err:
	printerr(0, "WARNING: downcall failed\n");
	return -1;
}

struct gss_verifier {
	u_int32_t	flav;
	gss_buffer_desc	body;
};

#define RPCSEC_GSS_SEQ_WIN	5

static int
send_response(FILE *f, gss_buffer_desc *in_handle, gss_buffer_desc *in_token,
	      u_int32_t maj_stat, u_int32_t min_stat,
	      gss_buffer_desc *out_handle, gss_buffer_desc *out_token)
{
	char buf[2 * 4096];
	char *bp = buf;
	int blen = sizeof(buf);
	/* XXXARG: */
	int g;

	printerr(1, "sending null reply\n");

	qword_addhex(&bp, &blen, in_handle->value, in_handle->length);
	qword_addhex(&bp, &blen, in_token->value, in_token->length);
	qword_addint(&bp, &blen, 0x7fffffff); /*XXX need a better timeout */
	qword_addint(&bp, &blen, maj_stat);
	qword_addint(&bp, &blen, min_stat);
	qword_addhex(&bp, &blen, out_handle->value, out_handle->length);
	qword_addhex(&bp, &blen, out_token->value, out_token->length);
	qword_addeol(&bp, &blen);
	if (blen <= 0) {
		printerr(0, "WARNING: send_respsonse: message too long\n");
		return -1;
	}
	g = open(SVCGSSD_INIT_CHANNEL, O_WRONLY);
	if (g == -1) {
		printerr(0, "WARNING: open %s failed: %s\n",
				SVCGSSD_INIT_CHANNEL, strerror(errno));
		return -1;
	}
	*bp = '\0';
	printerr(1, "writing message: %s", buf);
	if (write(g, buf, bp - buf) == -1) {
		printerr(0, "WARNING: failed to write message\n");
		close(g);
		return -1;
	}
	close(g);
	return 0;
}

#define rpc_auth_ok			0
#define rpc_autherr_badcred		1
#define rpc_autherr_rejectedcred	2
#define rpc_autherr_badverf		3
#define rpc_autherr_rejectedverf	4
#define rpc_autherr_tooweak		5
#define rpcsec_gsserr_credproblem	13
#define rpcsec_gsserr_ctxproblem	14

static void
add_supplementary_groups(char *secname, char *name, struct svc_cred *cred)
{
	int ret;
	static gid_t *groups = NULL;

	cred->cr_ngroups = NGROUPS;
	ret = nfs4_gss_princ_to_grouplist(secname, name,
			cred->cr_groups, &cred->cr_ngroups);
	if (ret < 0) {
		groups = realloc(groups, cred->cr_ngroups*sizeof(gid_t));
		ret = nfs4_gss_princ_to_grouplist(secname, name,
				groups, &cred->cr_ngroups);
		if (ret < 0)
			cred->cr_ngroups = 0;
		else {
			if (cred->cr_ngroups > NGROUPS)
				cred->cr_ngroups = NGROUPS;
			memcpy(cred->cr_groups, groups,
					cred->cr_ngroups*sizeof(gid_t));
		}
	}
}

static int
get_ids(gss_name_t client_name, gss_OID mech, struct svc_cred *cred)
{
	u_int32_t	maj_stat, min_stat;
	gss_buffer_desc	name;
	char		*sname;
	int		res = -1;
	uid_t		uid, gid;
	gss_OID		name_type;
	char		*secname;
	gid_t		*groups;

	maj_stat = gss_display_name(&min_stat, client_name, &name, &name_type);
	if (maj_stat != GSS_S_COMPLETE)
		goto out;
	if (!(sname = calloc(name.length + 1, 1)))
		goto out;
	memcpy(sname, name.value, name.length);
	printerr(1, "sname = %s\n", sname);

	res = -EINVAL;
	if ((secname = mech2file(mech)) == NULL)
		goto out_free;
	nfs4_init_name_mapping(NULL); /* XXX: should only do this once */
	res = nfs4_gss_princ_to_ids(secname, sname, &uid, &gid);
	if (res < 0)
		goto out_free;
	cred->cr_uid = uid;
	cred->cr_gid = gid;
	add_supplementary_groups(secname, sname, cred);
	res = 0;
out_free:
	free(sname);
out:
	if (res)
		printerr(0, "WARNING: get_uid failed\n");
	return res;
}

void
print_hexl(int pri, unsigned char *cp, int length)
{
	int i, j, jm;
	unsigned char c;

	printerr(pri, "length %d\n",length);
	printerr(pri, "\n");

	for (i = 0; i < length; i += 0x10) {
		printerr(pri, "  %04x: ", (u_int)i);
		jm = length - i;
		jm = jm > 16 ? 16 : jm;

		for (j = 0; j < jm; j++) {
			if ((j % 2) == 1)
				printerr(pri,"%02x ", (u_int)cp[i+j]);
			else
				printerr(pri,"%02x", (u_int)cp[i+j]);
		}
		for (; j < 16; j++) {
			if ((j % 2) == 1)
				printerr(pri,"   ");
			else
				printerr(pri,"  ");
		}
		printerr(pri," ");

		for (j = 0; j < jm; j++) {
			c = cp[i+j];
			c = isprint(c) ? c : '.';
			printerr(pri,"%c", c);
		}
		printerr(pri,"\n");
	}
}

void
handle_nullreq(FILE *f) {
	/* XXX initialize to a random integer to reduce chances of unnecessary
	 * invalidation of existing ctx's on restarting svcgssd. */
	static u_int32_t	handle_seq = 0;
	char			in_tok_buf[8192];
	char			in_handle_buf[15];
	char			out_handle_buf[15];
	gss_buffer_desc		in_tok = {.value = in_tok_buf},
				out_tok = {.value = NULL},
				in_handle = {.value = in_handle_buf},
				out_handle = {.value = out_handle_buf},
				ctx_token = {.value = NULL},
	/* XXX isn't there a define for this?: */
				null_token = {.value = NULL};
	u_int32_t		ret_flags;
	gss_ctx_id_t		ctx = GSS_C_NO_CONTEXT;
	gss_name_t		client_name;
	gss_OID			mech;
	u_int32_t		maj_stat = GSS_S_FAILURE, min_stat = 0;
	struct svc_cred		cred;
	static char		*lbuf = NULL;
	static int		lbuflen = 0;
	static char		*cp;

	printerr(1, "handling null request\n");

	if (readline(fileno(f), &lbuf, &lbuflen) != 1) {
		printerr(0, "WARNING: handle_nullreq: "
			    "failed reading request\n");
		return;
	}

	cp = lbuf;

	in_handle.length = (size_t) qword_get(&cp, in_handle.value,
					      sizeof(in_handle_buf));
	printerr(2, "in_handle: \n");
	print_hexl(2, in_handle.value, in_handle.length);
	handle_seq++;
	out_handle.length = sizeof(handle_seq);
	memcpy(out_handle.value, &handle_seq, sizeof(handle_seq));

	in_tok.length = (size_t) qword_get(&cp, in_tok.value,
					   sizeof(in_tok_buf));
	printerr(2, "in_tok: \n");
	print_hexl(2, in_tok.value, in_tok.length);

	if (in_tok.length < 0) {
		printerr(0, "WARNING: handle_nullreq: "
			    "failed parsing request\n");
		goto out_err;
	}

	if (in_handle.length != 0) { /* CONTINUE_INIT case */
		printerr(0, "WARNING: handle_nullreq: "
			    "CONTINUE_INIT unsupported\n");
		goto out_err;
	}

	maj_stat = gss_accept_sec_context(&min_stat, &ctx, gssd_creds,
			&in_tok, GSS_C_NO_CHANNEL_BINDINGS, &client_name,
			&mech, &out_tok, &ret_flags, NULL, NULL);
	if (maj_stat != GSS_S_COMPLETE) {
		printerr(0, "WARNING: gss_accept_sec_context failed\n");
		pgsserr("handle_nullreq: gss_accept_sec_context",
			maj_stat, min_stat, mech);
		goto out_err;
	}
	if (get_ids(client_name, mech, &cred)) {
		printerr(0, "WARNING: handle_nullreq: get_uid failed\n");
		maj_stat = GSS_S_BAD_NAME; /* XXX ? */
		goto out_err;
	}

	/* kernel needs ctx to calculate verifier on null response, so
	 * must give it context before doing null call: */
	if (serialize_context_for_kernel(ctx, &ctx_token)) {
		printerr(0, "WARNING: handle_nullreq: "
			    "serialize_context_for_kernel failed\n");
		maj_stat = GSS_S_FAILURE;
		goto out_err;
	}
	do_svc_downcall(&out_handle, &cred, mech, &ctx_token);
	send_response(f, &in_handle, &in_tok, maj_stat, min_stat,
			&out_handle, &out_tok);
	goto out;
out_err:
	send_response(f, &in_handle, &in_tok, maj_stat, min_stat,
			&null_token, &null_token);
out:
	if (ctx_token.value != NULL)
		free(ctx_token.value);
	printerr(1, "finished handling null request\n");
	return;
}