libptytty/src/fdpass.C

/*----------------------------------------------------------------------*
 * File:        fdpass.C
 *----------------------------------------------------------------------*
 *
 * All portions of code are copyright by their respective author/s.
 * Copyright (c) 2005-2006,2012 Marc Lehmann <schmorp@schmorp.de>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 *----------------------------------------------------------------------*/

#include "config.h"

#include <stddef.h> // needed by broken bsds for NULL used in sys/uio.h
#include <stdlib.h>

#include <sys/types.h>
#include <sys/uio.h>
#include <sys/socket.h>

#include "libptytty.h"

// CMSG_SPACE & CMSG_LEN are rfc2292 extensions to unix
#ifndef CMSG_SPACE
# define CMSG_SPACE(len) (sizeof (cmsghdr) + len)
#endif

#ifndef CMSG_LEN
# define CMSG_LEN(len) (sizeof (cmsghdr) + len)
#endif

bool
ptytty::send_fd (int socket, int fd)
{
  void *buf = malloc (CMSG_SPACE (sizeof (int)));

  if (!buf)
    return 0;

  msghdr msg;
  iovec iov;
  cmsghdr *cmsg;
  char data = 0;

  iov.iov_base = &data;
  iov.iov_len  = 1;

  msg.msg_name       = 0;
  msg.msg_namelen    = 0;
  msg.msg_iov        = &iov;
  msg.msg_iovlen     = 1;
  msg.msg_control    = buf;
  msg.msg_controllen = CMSG_SPACE (sizeof (int));

  cmsg = CMSG_FIRSTHDR (&msg);
  cmsg->cmsg_level = SOL_SOCKET;
  cmsg->cmsg_type  = SCM_RIGHTS;
  cmsg->cmsg_len   = CMSG_LEN (sizeof (int));

  *(int *)CMSG_DATA (cmsg) = fd;

  ssize_t result = sendmsg (socket, &msg, 0);

  free (buf);

  return result >= 0;
}

int
ptytty::recv_fd (int socket)
{
  void *buf = malloc (CMSG_SPACE (sizeof (int)));

  if (!buf)
    return -1;

  msghdr msg;
  iovec iov;
  char data = 1;

  iov.iov_base = &data;
  iov.iov_len  = 1;

  msg.msg_name       = 0;
  msg.msg_namelen    = 0;
  msg.msg_iov        = &iov;
  msg.msg_iovlen     = 1;
  msg.msg_control    = buf;
  msg.msg_controllen = CMSG_SPACE (sizeof (int));

  int fd = -1;

  if (recvmsg (socket, &msg, 0) >  0
      && data                   == 0)
    {
      cmsghdr *cmsg = CMSG_FIRSTHDR (&msg);

      if (cmsg
          && cmsg->cmsg_level == SOL_SOCKET
          && cmsg->cmsg_type  == SCM_RIGHTS
          && cmsg->cmsg_len   >= CMSG_LEN (sizeof (int)))
        fd = *(int *)CMSG_DATA (cmsg);
    }

  free (buf);

  return fd;
}

Revision:	1.20
Committed:	Fri Oct 31 07:57:54 2014 UTC (11 years, 10 months ago) by sf-exg
Content type:	text/plain
Branch:	MAIN
CVS Tags:	rxvt-unicode-rel-9_26, rxvt-unicode-rel-9_25, rxvt-unicode-rel-9_22, rxvt-unicode-rel-9_21, rel-1_8, rel-1_7
Changes since 1.19:	+5 -5 lines
Log Message:	Check CMSG_FIRSTHDR instead of msg_controllen to verify the validity of the buffer returned by recvmsg.
#	User	Rev	Content
1	root	1.4	/----------------------------------------------------------------------
2	root	1.1	* File: fdpass.C
3			----------------------------------------------------------------------
4			*
5			* All portions of code are copyright by their respective author/s.
6	root	1.14	* Copyright (c) 2005-2006,2012 Marc Lehmann <schmorp@schmorp.de>
7	root	1.1	*
8			* This program is free software; you can redistribute it and/or modify
9			* it under the terms of the GNU General Public License as published by
10	sf-exg	1.19	* the Free Software Foundation; either version 2 of the License, or
11	root	1.1	* (at your option) any later version.
12			*
13			* This program is distributed in the hope that it will be useful,
14			* but WITHOUT ANY WARRANTY; without even the implied warranty of
15			* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16			* GNU General Public License for more details.
17			*
18			* You should have received a copy of the GNU General Public License
19			* along with this program; if not, write to the Free Software
20			* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
21			----------------------------------------------------------------------/
22
23	sf-exg	1.11	#include "config.h"
24	root	1.1
25	sf-exg	1.17	#include <stddef.h> // needed by broken bsds for NULL used in sys/uio.h
26	sf-exg	1.16	#include <stdlib.h>
27	root	1.6
28	ayin	1.9	#include <sys/types.h>
29	root	1.2	#include <sys/uio.h>
30	root	1.1	#include <sys/socket.h>
31
32	root	1.3	#include "libptytty.h"
33	root	1.1
34	root	1.10	// CMSG_SPACE & CMSG_LEN are rfc2292 extensions to unix
35			#ifndef CMSG_SPACE
36			# define CMSG_SPACE(len) (sizeof (cmsghdr) + len)
37			#endif
38
39			#ifndef CMSG_LEN
40	root	1.1	# define CMSG_LEN(len) (sizeof (cmsghdr) + len)
41			#endif
42
43	root	1.5	bool
44	root	1.3	ptytty::send_fd (int socket, int fd)
45	root	1.1	{
46	root	1.10	void *buf = malloc (CMSG_SPACE (sizeof (int)));
47
48			if (!buf)
49			return 0;
50
51	root	1.1	msghdr msg;
52			iovec iov;
53	root	1.10	cmsghdr *cmsg;
54	root	1.1	char data = 0;
55
56			iov.iov_base = &data;
57			iov.iov_len = 1;
58
59			msg.msg_name = 0;
60			msg.msg_namelen = 0;
61			msg.msg_iov = &iov;
62			msg.msg_iovlen = 1;
63	root	1.10	msg.msg_control = buf;
64			msg.msg_controllen = CMSG_SPACE (sizeof (int));
65	root	1.1
66	root	1.10	cmsg = CMSG_FIRSTHDR (&msg);
67	root	1.1	cmsg->cmsg_level = SOL_SOCKET;
68			cmsg->cmsg_type = SCM_RIGHTS;
69			cmsg->cmsg_len = CMSG_LEN (sizeof (int));
70
71			(int )CMSG_DATA (cmsg) = fd;
72
73	root	1.10	ssize_t result = sendmsg (socket, &msg, 0);
74
75			free (buf);
76	root	1.1
77	root	1.10	return result >= 0;
78	root	1.1	}
79
80			int
81	root	1.3	ptytty::recv_fd (int socket)
82	root	1.1	{
83	root	1.10	void *buf = malloc (CMSG_SPACE (sizeof (int)));
84
85			if (!buf)
86			return -1;
87
88	root	1.1	msghdr msg;
89			iovec iov;
90			char data = 1;
91
92			iov.iov_base = &data;
93			iov.iov_len = 1;
94
95			msg.msg_name = 0;
96			msg.msg_namelen = 0;
97			msg.msg_iov = &iov;
98			msg.msg_iovlen = 1;
99			msg.msg_control = buf;
100	root	1.10	msg.msg_controllen = CMSG_SPACE (sizeof (int));
101	root	1.1
102	root	1.10	int fd = -1;
103
104			if (recvmsg (socket, &msg, 0) > 0
105	sf-exg	1.20	&& data == 0)
106	root	1.10	{
107			cmsghdr *cmsg = CMSG_FIRSTHDR (&msg);
108	root	1.1
109	sf-exg	1.20	if (cmsg
110			&& cmsg->cmsg_level == SOL_SOCKET
111			&& cmsg->cmsg_type == SCM_RIGHTS
112			&& cmsg->cmsg_len >= CMSG_LEN (sizeof (int)))
113	root	1.10	fd = (int )CMSG_DATA (cmsg);
114			}
115	root	1.1
116	root	1.10	free (buf);
117	root	1.1
118	root	1.10	return fd;
119	root	1.1	}
120