gck-rpc-module.c

/* -*- Mode: C; indent-tabs-mode: t; c-basic-offset: 8; tab-width: 8 -*- */
/* gkr-pkcs11-rpc-module.c - a PKCS#11 module which communicates with another process

   Copyright (C) 2008, Stefan Walter

   The Gnome Keyring Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Library General Public License as
   published by the Free Software Foundation; either version 2 of the
   License, or (at your option) any later version.

   The Gnome Keyring Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Library General Public License for more details.

   You should have received a copy of the GNU Library General Public
   License along with the Gnome Library; see the file COPYING.LIB.  If not,
   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
   Boston, MA 02111-1307, USA.

   Author: Stef Walter <stef@memberwebs.com>
*/

#include "config.h"

#include "gck-rpc-layer.h"
#include "gck-rpc-private.h"

#include "pkcs11/pkcs11.h"

#include <sys/types.h>
#include <sys/param.h>
#ifdef __MINGW32__
# include <winsock2.h>
#else
# include <sys/socket.h>
# include <sys/un.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <netinet/tcp.h>
# include <netdb.h>
#endif

#include <stdlib.h>
#include <limits.h>
#include <ctype.h>
#include <stdint.h>
#include <pthread.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
#include <stdarg.h>
#include <stdio.h>
#include <string.h>

/* -------------------------------------------------------------------
 * GLOBALS / DEFINES
 */

/* Various mutexes */
static pthread_mutex_t init_mutex = PTHREAD_MUTEX_INITIALIZER;

/* Whether we've been initialized, and on what process id it happened */
static int pkcs11_initialized = 0;
static pid_t pkcs11_initialized_pid = 0;
static uint64_t pkcs11_app_id = 0;

/* The socket to connect to */
static char pkcs11_socket_path[MAXPATHLEN] = { 0, };

/* The error used by us when parsing of rpc message fails */
#define PARSE_ERROR   CKR_DEVICE_ERROR

/* -----------------------------------------------------------------------------
 * LOGGING and DEBUGGING
 */
#define DEBUG_OUTPUT 0
#if DEBUG_OUTPUT
#define debug(x) gck_rpc_debug x
#else
#define debug(x)
#endif
#define warning(x) gck_rpc_warn x

#define return_val_if_fail(x, v) \
	if (!(x)) { gck_rpc_warn ("'%s' not true at %s", #x, __func__); return v; }

void gck_rpc_log(const char *msg, ...)
{
	va_list ap;

	va_start(ap, msg);
	vfprintf(stderr, msg, ap);
	fprintf(stderr, "\n");
	va_end(ap);
}

/* -----------------------------------------------------------------------------
 * MODULE ARGUMENTS
 */

static void parse_argument(char *arg)
{
	char *value;

	value = arg + strcspn(arg, ":=");
	if (!*value)
		value = NULL;
	else
		*(value++) = 0;

	/* Setup the socket path from the arguments */
	if (strcmp(arg, "socket") == 0)
		snprintf(pkcs11_socket_path, sizeof(pkcs11_socket_path), "%s",
			 value);
	else
		warning(("unrecognized argument: %s", arg));
}

static void parse_arguments(const char *string)
{
	char quote = '\0';
	char *src, *dup, *at, *arg;

	if (!string)
		return;

	src = dup = strdup(string);
	if (!dup) {
		warning(("couldn't allocate memory for argument string"));
		return;
	}

	for (arg = at = src; *src; src++) {

		/* Matching quote */
		if (quote == *src) {
			quote = '\0';

			/* Inside of quotes */
		} else if (quote != '\0') {
			if (*src == '\\') {
				*at++ = *src++;
				if (!*src) {
					warning(("couldn't parse argument string: %s", string));
					goto done;
				}
				if (*src != quote)
					*at++ = '\\';
			}
			*at++ = *src;

			/* Space, not inside of quotes */
		} else if (isspace(*src)) {
			*at = 0;
			parse_argument(arg);
			arg = at;

			/* Other character outside of quotes */
		} else {
			switch (*src) {
			case '\'':
			case '"':
				quote = *src;
				break;
			case '\\':
				*at++ = *src++;
				if (!*src) {
					warning(("couldn't parse argument string: %s", string));
					goto done;
				}
				/* fall through */
			default:
				*at++ = *src;
				break;
			}
		}
	}

	if (at != arg)
		parse_argument(arg);

done:
	free(dup);
}

/* -----------------------------------------------------------------------------
 * CALL SESSION
 */

enum CallStatus {
	CALL_INVALID,
	CALL_READY,
	CALL_PREP,
	CALL_TRANSIT,
	CALL_PARSE
};

typedef struct _CallState {
	int socket;		/* The connection we're sending on */
	GckRpcMessage *req;	/* The current request */
	GckRpcMessage *resp;	/* The current response */
	int call_status;
	struct _CallState *next;	/* For pooling of completed sockets */
} CallState;

/* Maximum number of idle calls */
#define MAX_CALL_STATE_POOL 8

/* All call unused call states are in this list */
static CallState *call_state_pool = NULL;
static unsigned int n_call_state_pool = 0;

/* Mutex to protect above call state list */
static pthread_mutex_t call_state_mutex = PTHREAD_MUTEX_INITIALIZER;

/* Allocator for call session buffers */
static void *call_allocator(void *p, size_t sz)
{
	void *res = realloc(p, (size_t) sz);
	if (!res && sz)
		warning(("memory allocation of %lu bytes failed", sz));
	return res;
}

static void call_disconnect(CallState * cs)
{
	assert(cs);

	if (cs->socket != -1) {
		debug(("disconnected socket"));
		close(cs->socket);
		cs->socket = -1;
	}
}

/* Write all data to session socket.  */
static CK_RV call_write(CallState * cs, unsigned char *data, size_t len)
{
	int fd, r;

	assert(cs);
	assert(data);
	assert(len > 0);

	while (len > 0) {

		fd = cs->socket;
		if (fd == -1) {
			warning(("couldn't send data: socket has been closed"));
			return CKR_DEVICE_ERROR;
		}

                r = send(fd, (void *)data, len, 0);

		if (r == -1) {
			if (errno == EPIPE) {
				warning(("couldn't send data: daemon closed connection"));
				call_disconnect(cs);
				return CKR_DEVICE_ERROR;
			} else if (errno != EAGAIN && errno != EINTR) {
				warning(("couldn't send data: %s",
					 strerror(errno)));
				return CKR_DEVICE_ERROR;
			}
		} else {
			debug(("wrote %d bytes", r));
			data += r;
			len -= r;
		}
	}

	return CKR_OK;
}

/* Read a certain amount of data from session socket. */
static CK_RV call_read(CallState * cs, unsigned char *data, size_t len)
{
	int fd, r;

	assert(cs);
	assert(data);
	assert(len > 0);

	while (len > 0) {

		fd = cs->socket;
		if (fd == -1) {
			warning(("couldn't receive data: session socket has been closed"));
			return CKR_DEVICE_ERROR;
		}

                r = recv(fd, (void *)data, len, 0);

		if (r == 0) {
			warning(("couldn't receive data: daemon closed connection"));
			call_disconnect(cs);
			return CKR_DEVICE_ERROR;
		} else if (r == -1) {
			if (errno != EAGAIN && errno != EINTR) {
				warning(("couldn't receive data: %s",
					 strerror(errno)));
				return CKR_DEVICE_ERROR;
			}
		} else {
			debug(("read %d bytes", r));
			data += r;
			len -= r;
		}
	}

	return CKR_OK;
}

static int _connect_to_host_port(char *host, char *port)
{
	char hoststr[NI_MAXHOST], portstr[NI_MAXSERV], hostport[NI_MAXHOST + NI_MAXSERV + 1];
	struct addrinfo *ai, *first, hints;
	int res, sock, one = 1;

	memset(&hints, 0, sizeof(struct addrinfo));
	hints.ai_family = AF_UNSPEC;		/* Either IPv4 or IPv6 */
	hints.ai_socktype = SOCK_STREAM;	/* Only stream oriented sockets */

	if ((res = getaddrinfo(host, port, &hints, &ai)) < 0) {
		gck_rpc_warn("couldn't resolve host '%.100s' or service '%.100s' : %.100s\n",
			     host, port, gai_strerror(res));
		return -1;
	}

	sock = -1;
	first = ai;

	/* Loop through the sockets returned and see if we can find one that accepts
	 * our options and connect()
	 */
	while (ai) {
		if ((res = getnameinfo(ai->ai_addr, ai->ai_addrlen,
				       hoststr, sizeof(hoststr), portstr, sizeof(portstr),
				       NI_NUMERICHOST | NI_NUMERICSERV)) != 0) {
			gck_rpc_warn("couldn't call getnameinfo on pkcs11 socket (%.100s %.100s): %.100s",
				     host, port, gai_strerror(res));
			sock = -1;
			continue;
		}

		snprintf(hostport, sizeof(hostport),
			 (ai->ai_family == AF_INET6) ? "[%s]:%s" : "%s:%s", hoststr, portstr);

		sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);

		if (sock >= 0) {
			if (setsockopt(sock, IPPROTO_TCP, TCP_NODELAY,
				       (char *)&one, sizeof (one)) == -1) {
				gck_rpc_warn("couldn't set pkcs11 "
					     "socket protocol options (%.100s): %.100s",
					     hostport, strerror (errno));
				goto next;
			}

#ifndef __MINGW32__
			/* close on exec */
			if (fcntl(sock, F_SETFD, 1) == -1) {
				gck_rpc_warn("couldn't secure socket (%.100s): %.100s",
					     hostport, strerror(errno));
				goto next;
			}
#endif

			if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
				close(sock);
				warning(("couldn't connect (%.100s): %s",
					 hostport, strerror(errno)));
				goto next;
			}

			break;
		next:
			close(sock);
			sock = -1;
		}
		ai = ai->ai_next;
	}

	if (sock < 0) {
		gck_rpc_warn("couldn't create pkcs11 socket (%.100s): %.100s\n",
			     pkcs11_socket_path, strerror(errno));
		sock = -1;
		goto out;
	}

 out:
	freeaddrinfo(first);

	return sock;
}

static CK_RV call_connect(CallState * cs)
{
	struct sockaddr_un addr;
	int sock;

	assert(cs);
	assert(cs->socket == -1);
	assert(cs->call_status == CALL_INVALID);
	assert(pkcs11_socket_path[0]);

	debug(("connecting to: %s", pkcs11_socket_path));

	memset(&addr, 0, sizeof(addr));

	if (!strncmp("tcp://", pkcs11_socket_path, 6)) {
		char *host, *port;

		if (! gck_rpc_parse_host_port(pkcs11_socket_path + 6, &host, &port)) {
			gck_rpc_warn("failed parsing pkcs11 socket : %s",
				     pkcs11_socket_path);
			return CKR_DEVICE_ERROR;
		}

		if ((sock = _connect_to_host_port(host, port)) == -1) {
			free(host);
			return CKR_DEVICE_ERROR;
		}

		free(host);
	} else {
		addr.sun_family = AF_UNIX;
		strncpy(addr.sun_path, pkcs11_socket_path,
			sizeof(addr.sun_path));

		sock = socket(AF_UNIX, SOCK_STREAM, 0);
		if (sock < 0) {
			warning(("couldn't open socket: %s", strerror(errno)));
			return CKR_DEVICE_ERROR;
		}


#ifndef __MINGW32__
		/* close on exec */
		if (fcntl(sock, F_SETFD, 1) == -1) {
			close(sock);
			warning(("couldn't secure socket: %s", strerror(errno)));
			return CKR_DEVICE_ERROR;
		}
#endif

		if (connect(sock, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
			close(sock);
			warning(("couldn't connect to: %s: %s", pkcs11_socket_path,
				 strerror(errno)));
			return CKR_DEVICE_ERROR;
		}
	}

	cs->socket = sock;
	cs->call_status = CALL_READY;
	debug(("connected socket"));

	return call_write(cs, (unsigned char*)&pkcs11_app_id,
			  sizeof(pkcs11_app_id));
}

static void call_destroy(void *value)
{
	CallState *cs = value;

	if (value) {
		call_disconnect(cs);
		assert(cs->socket == -1);

		gck_rpc_message_free(cs->req);
		gck_rpc_message_free(cs->resp);

		free(cs);

		debug(("destroyed state"));
	}
}

static CK_RV call_lookup(CallState ** ret)
{
	CallState *cs = NULL;
	CK_RV rv;

	assert(ret);

	pthread_mutex_lock(&call_state_mutex);

	/* Pop one from the pool if possible */
	if (call_state_pool != NULL) {
		cs = call_state_pool;
		call_state_pool = cs->next;
		cs->next = NULL;
		assert(n_call_state_pool > 0);
		--n_call_state_pool;
	}

	pthread_mutex_unlock(&call_state_mutex);

	if (cs == NULL) {
		cs = calloc(1, sizeof(CallState));
		if (cs == NULL)
			return CKR_HOST_MEMORY;
		cs->socket = -1;
		cs->call_status = CALL_INVALID;

		/* Try to connect the call */
		rv = call_connect(cs);
		if (rv != CKR_OK) {
			free(cs);
			return rv;
		}
	}

	assert(cs->call_status == CALL_READY);
	assert(cs->socket != -1);
	assert(cs->next == NULL);
	*ret = cs;
	return CKR_OK;
}

/* Perform the initial setup for a new call. */
static CK_RV call_prepare(CallState * cs, int call_id)
{
	assert(cs);
	assert(cs->call_status == CALL_READY);

	/* Allocate a new request if we've lost the old one */
	if (!cs->req) {
		cs->req = gck_rpc_message_new(call_allocator);
		if (!cs->req) {
			warning(("cannot allocate request buffer: out of memory"));
			return CKR_HOST_MEMORY;
		}
	}

	/* Put in the Call ID and signature */
	gck_rpc_message_reset(cs->req);
	if (!gck_rpc_message_prep(cs->req, call_id, GCK_RPC_REQUEST))
		return CKR_HOST_MEMORY;

	debug(("prepared call: %d", call_id));

	/* Ready to fill in arguments */
	cs->call_status = CALL_PREP;
	return CKR_OK;
}

/*
 * Used by call_session_do_call() to actually send the message to the daemon.
 * Note how we unlock and relock the session during the call.
 */
static CK_RV call_send_recv(CallState * cs)
{
	GckRpcMessage *req, *resp;
	unsigned char buf[4];
	uint32_t len;
	CK_RV ret;

	assert(cs);
	assert(cs->req);
	assert(cs->call_status == CALL_PREP);

	cs->call_status = CALL_TRANSIT;

	/* Setup the response buffer properly */
	if (!cs->resp) {
		/* TODO: Do secrets or passwords ever flow through here? */
		cs->resp = gck_rpc_message_new(call_allocator);
		if (!cs->resp) {
			warning(("couldn't allocate response buffer: out of memory"));
			return CKR_HOST_MEMORY;
		}
	}
	gck_rpc_message_reset(cs->resp);

	/*
	 * Now as an additional check to make sure nothing nasty will
	 * happen while we are unlocked, we remove the request and
	 * response from the session during the action.
	 */
	req = cs->req;
	resp = cs->resp;
	cs->req = cs->resp = NULL;

	/* Send the number of bytes, and then the data */

	egg_buffer_encode_uint32(buf, req->buffer.len);
	ret = call_write(cs, buf, 4);
	if (ret != CKR_OK)
		goto cleanup;
	ret = call_write(cs, req->buffer.buf, req->buffer.len);
	if (ret != CKR_OK)
		goto cleanup;

	/* Now read out the number of bytes, and then the data */
	ret = call_read(cs, buf, 4);
	if (ret != CKR_OK)
		goto cleanup;

	len = egg_buffer_decode_uint32(buf);
	if (!egg_buffer_reserve(&resp->buffer, len + resp->buffer.len)) {
		warning(("couldn't allocate %u byte response area: out of memory", len));
		ret = CKR_HOST_MEMORY;
		goto cleanup;
	}

	ret = call_read(cs, resp->buffer.buf, len);
	if (ret != CKR_OK)
		goto cleanup;

	egg_buffer_add_empty(&resp->buffer, len);
	if (!gck_rpc_message_parse(resp, GCK_RPC_RESPONSE))
		goto cleanup;

	debug(("received response from daemon"));

cleanup:
	/* Make sure nobody else used this thread while unlocked */
	assert(cs->call_status == CALL_TRANSIT);
	assert(cs->resp == NULL);
	cs->resp = resp;
	assert(cs->req == NULL);
	cs->req = req;

	return ret;
}

/*
 * At this point the request is ready. So we validate it, and we send it to
 * the daemon for a response.
 */
static CK_RV call_run(CallState * cs)
{
	CK_RV ret = CKR_OK;
	CK_ULONG ckerr;

	assert(cs);
	assert(cs->req);
	assert(cs->call_status == CALL_PREP);
	assert(cs->socket != -1);

	/* Did building the call fail? */
	if (gck_rpc_message_buffer_error(cs->req)) {
		warning(("couldn't allocate request area: out of memory"));
		return CKR_HOST_MEMORY;
	}

	/* Make sure that the signature is valid */
	assert(gck_rpc_message_is_verified(cs->req));

	/* Do the dialog with daemon */
	ret = call_send_recv(cs);

	cs->call_status = CALL_PARSE;

	if (ret != CKR_OK)
		return ret;

	/* If it's an error code then return it */
	if (cs->resp->call_id == GCK_RPC_CALL_ERROR) {

		if (!gck_rpc_message_read_ulong(cs->resp, &ckerr)) {
			warning(("invalid error response from gnome-keyring-daemon: too short"));
			return CKR_DEVICE_ERROR;
		}

		if (ckerr <= CKR_OK) {
			warning(("invalid error response from gnome-keyring-daemon: bad error code"));
			return CKR_DEVICE_ERROR;
		}

		/* An error code from the daemon */
		return (CK_RV) ckerr;
	}

	/* Make sure daemon answered the right call */
	if (cs->req->call_id != cs->resp->call_id) {
		warning(("invalid response from gnome-keyring-daemon: call mismatch"));
		return CKR_DEVICE_ERROR;
	}

	assert(!gck_rpc_message_buffer_error(cs->resp));
	debug(("parsing response values"));

	return CKR_OK;
}

static CK_RV call_done(CallState * cs, CK_RV ret)
{
	assert(cs);
	assert(cs->call_status > CALL_INVALID);

	if (cs->call_status == CALL_PARSE && cs->req && cs->resp) {

		/* Check for parsing errors that were not caught elsewhere */
		if (ret == CKR_OK) {

			if (gck_rpc_message_buffer_error(cs->resp)) {
				warning(("invalid response from gnome-keyring-daemon: bad argument data"));
				ret = CKR_GENERAL_ERROR;
			} else {
				/* Double check that the signature matched our decoding */
				assert(gck_rpc_message_is_verified(cs->resp));
			}
		}
	}

	/* Certain error codes cause us to discard the conenction */
	if (ret != CKR_DEVICE_ERROR && ret != CKR_DEVICE_REMOVED
	    && cs->socket != -1) {

		/* Try and stash it away for later use */
		pthread_mutex_lock(&call_state_mutex);

		if (n_call_state_pool < MAX_CALL_STATE_POOL) {
			cs->call_status = CALL_READY;
			assert(cs->next == NULL);
			cs->next = call_state_pool;
			call_state_pool = cs;
			++n_call_state_pool;
			cs = NULL;
		}

		pthread_mutex_unlock(&call_state_mutex);
	}

	if (cs != NULL)
		call_destroy(cs);

	return ret;
}

/* -----------------------------------------------------------------------------
 * MODULE SPECIFIC PROTOCOL CODE
 */

static CK_RV
proto_read_attribute_array(GckRpcMessage * msg, CK_ATTRIBUTE_PTR arr,
			   CK_ULONG len)
{
	uint32_t i, num, value, type;
	CK_ATTRIBUTE_PTR attr;
	const unsigned char *attrval;
	size_t attrlen;
	unsigned char validity;
	CK_RV ret;

	/* Removed assertion. len == 0 is valid for some ret's,
	 * see proto_write_attribute_array().
	 * assert(len);
	 */
	assert(msg);

	/* Make sure this is in the right order */
	assert(!msg->signature || gck_rpc_message_verify_part(msg, "aA"));

	/* Get the number of items. We need this value to be correct */
	if (!egg_buffer_get_uint32
	    (&msg->buffer, msg->parsed, &msg->parsed, &num))
		return PARSE_ERROR;

	if (len != num) {

		/*
		 * This should never happen in normal operation. It denotes a goof up
		 * on the other side of our RPC. We should be indicating the exact number
		 * of attributes to the other side. And it should respond with the same
		 * number.
		 */

		warning(("received an attribute array with wrong number of attributes"));
		return PARSE_ERROR;
	}

	ret = CKR_OK;

	/* We need to go ahead and read everything in all cases */
	for (i = 0; i < num; ++i) {

		/* The attribute type */
		egg_buffer_get_uint32(&msg->buffer, msg->parsed,
				      &msg->parsed, &type);

		/* Attribute validity */
		egg_buffer_get_byte(&msg->buffer, msg->parsed,
				    &msg->parsed, &validity);

		/* And the data itself */
		if (validity) {
			if (egg_buffer_get_uint32
			    (&msg->buffer, msg->parsed, &msg->parsed, &value)
			    && egg_buffer_get_byte_array(&msg->buffer,
							 msg->parsed,
							 &msg->parsed, &attrval,
							 &attrlen)) {
				if (attrval && value != attrlen) {
					warning(("attribute length does not match attribute data"));
					return PARSE_ERROR;
				}
				attrlen = value;
			} else {
				warning(("failed reading byte array"));
				return PARSE_ERROR;
			}
		}

		/* Don't act on this data unless no errors */
		if (egg_buffer_has_error(&msg->buffer))
			break;

		/* Try and stuff it in the output data */
		if (arr) {
			attr = &(arr[i]);
			if (attr->type != type) {
				warning(("returned attributes in invalid order"));
				return PARSE_ERROR;
			}

			if (validity) {
				/* Just requesting the attribute size */
				if (!attr->pValue) {
					attr->ulValueLen = attrlen;

					/* Wants attribute data, but too small */
				} else if (attr->ulValueLen < attrlen) {
					attr->ulValueLen = attrlen;
					ret = CKR_BUFFER_TOO_SMALL;

					/* Wants attribute data, value is null */
				} else if (attrval == NULL) {
					attr->ulValueLen = 0;

					/* Wants attribute data, enough space */
				} else {
					CK_ULONG a;

					/* Attribute len is an integer, but
					 * does not match CK_ULONG size, it's certainly
					 * a CK_ULONG from a different platform */
					if (attrlen == sizeof(uint64_t) &&
					    sizeof(CK_ULONG) != sizeof(uint64_t) &&
					    gck_rpc_has_ulong_parameter(attr->type)) {
						attrlen = sizeof(CK_ULONG);
						a = *(uint64_t *) attrval;
						attrval = (unsigned char *)&a;
					}
					attr->ulValueLen = attrlen;
					memcpy(attr->pValue, attrval, attrlen);
				}

				/* Not a valid attribute */
			} else {
				attr->ulValueLen = ((CK_ULONG) - 1);
			}
		}
	}

	if (egg_buffer_has_error(&msg->buffer))
		return PARSE_ERROR;

	/* Read in the code that goes along with these attributes */
	if (!gck_rpc_message_read_ulong(msg, &ret))
		return PARSE_ERROR;

	return ret;
}

static CK_RV
proto_read_byte_array(GckRpcMessage * msg, CK_BYTE_PTR arr,
		      CK_ULONG_PTR len, CK_ULONG max)
{
	const unsigned char *val;
	unsigned char valid;
	size_t vlen;

	assert(len);
	assert(msg);

	/* Make sure this is in the right order */
	assert(!msg->signature || gck_rpc_message_verify_part(msg, "ay"));

	/* A single byte which determines whether valid or not */
	if (!egg_buffer_get_byte
	    (&msg->buffer, msg->parsed, &msg->parsed, &valid))
		return PARSE_ERROR;

	/* If not valid, then just the length is encoded, this can signify CKR_BUFFER_TOO_SMALL */
	if (!valid) {
		uint32_t t_len;

		if (!egg_buffer_get_uint32
		    (&msg->buffer, msg->parsed, &msg->parsed,
		     & t_len))
			return PARSE_ERROR;

		*len = t_len;

		if (arr)
			return CKR_BUFFER_TOO_SMALL;
		else
			return CKR_OK;
	}

	/* Get the actual bytes */
	if (!egg_buffer_get_byte_array
	    (&msg->buffer, msg->parsed, &msg->parsed, &val, &vlen))
		return PARSE_ERROR;

	*len = vlen;

	/* Just asking us for size */
	if (!arr)
		return CKR_OK;

	if (max < vlen)
		return CKR_BUFFER_TOO_SMALL;

	/* Enough space, yay */
	memcpy(arr, val, vlen);
	return CKR_OK;
}

static CK_RV
proto_read_ulong_array(GckRpcMessage * msg, CK_ULONG_PTR arr,
		       CK_ULONG_PTR len, CK_ULONG max)
{
	uint32_t i, num;
	uint64_t val;
	unsigned char valid;

	assert(len);
	assert(msg);

	/* Make sure this is in the right order */
	assert(!msg->signature || gck_rpc_message_verify_part(msg, "au"));

	/* A single byte which determines whether valid or not */
	if (!egg_buffer_get_byte
	    (&msg->buffer, msg->parsed, &msg->parsed, &valid))
		return PARSE_ERROR;

	/* Get the number of items. */
	if (!egg_buffer_get_uint32
	    (&msg->buffer, msg->parsed, &msg->parsed, &num))
		return PARSE_ERROR;

	*len = num;

	/* If not valid, then just the length is encoded, this can signify CKR_BUFFER_TOO_SMALL */
	if (!valid) {
		if (arr)
			return CKR_BUFFER_TOO_SMALL;
		else
			return CKR_OK;
	}

	if (max < num)
		return CKR_BUFFER_TOO_SMALL;

	/* We need to go ahead and read everything in all cases */
	for (i = 0; i < num; ++i) {
		egg_buffer_get_uint64(&msg->buffer, msg->parsed, &msg->parsed,
				      &val);
		if (arr)
			arr[i] = (CK_ULONG) val;
	}

	return egg_buffer_has_error(&msg->buffer) ? PARSE_ERROR : CKR_OK;
}

static CK_RV proto_write_mechanism(GckRpcMessage * msg, CK_MECHANISM_PTR mech)
{
	assert(msg);
	assert(mech);

	/* Make sure this is in the right order */
	assert(!msg->signature || gck_rpc_message_verify_part(msg, "M"));

	/* The mechanism type */
	egg_buffer_add_uint32(&msg->buffer, mech->mechanism);

	/*
	 * PKCS#11 mechanism parameters are not easy to serialize. They're
	 * completely different for so many mechanisms, they contain
	 * pointers to arbitrary memory, and many callers don't initialize
	 * them completely or properly.
	 *
	 * We only support certain mechanisms.
	 *
	 * Also callers do yucky things like leaving parts of the structure
	 * pointing to garbage if they don't think it's going to be used.
	 */

	if (gck_rpc_mechanism_has_no_parameters(mech->mechanism))
		egg_buffer_add_byte_array(&msg->buffer, NULL, 0);
	else if (gck_rpc_mechanism_has_sane_parameters(mech->mechanism))
		egg_buffer_add_byte_array(&msg->buffer, mech->pParameter,
					  mech->ulParameterLen);