1 /* $OpenBSD: monitor_fdpass.c,v 1.22 2020/10/18 11:32:01 djm Exp $ */ 2 /* 3 * Copyright 2001 Niels Provos <provos@citi.umich.edu> 4 * All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25 */ 26 27 #include "includes.h" 28 29 #include <sys/types.h> 30 #include <sys/socket.h> 31 #include <sys/uio.h> 32 #ifdef HAVE_SYS_UN_H 33 #include <sys/un.h> 34 #endif 35 36 #include <errno.h> 37 #include <string.h> 38 #include <stdarg.h> 39 40 #ifdef HAVE_POLL_H 41 # include <poll.h> 42 #else 43 # ifdef HAVE_SYS_POLL_H 44 # include <sys/poll.h> 45 # endif 46 #endif 47 48 #include "log.h" 49 #include "monitor_fdpass.h" 50 51 int 52 mm_send_fd(int sock, int fd) 53 { 54 #if defined(HAVE_SENDMSG) && (defined(HAVE_ACCRIGHTS_IN_MSGHDR) || defined(HAVE_CONTROL_IN_MSGHDR)) 55 struct msghdr msg; 56 #ifndef HAVE_ACCRIGHTS_IN_MSGHDR 57 union { 58 struct cmsghdr hdr; 59 char buf[CMSG_SPACE(sizeof(int))]; 60 } cmsgbuf; 61 struct cmsghdr *cmsg; 62 #endif 63 struct iovec vec; 64 char ch = '\0'; 65 ssize_t n; 66 struct pollfd pfd; 67 68 memset(&msg, 0, sizeof(msg)); 69 #ifdef HAVE_ACCRIGHTS_IN_MSGHDR 70 msg.msg_accrights = (caddr_t)&fd; 71 msg.msg_accrightslen = sizeof(fd); 72 #else 73 memset(&cmsgbuf, 0, sizeof(cmsgbuf)); 74 msg.msg_control = (caddr_t)&cmsgbuf.buf; 75 msg.msg_controllen = sizeof(cmsgbuf.buf); 76 cmsg = CMSG_FIRSTHDR(&msg); 77 cmsg->cmsg_len = CMSG_LEN(sizeof(int)); 78 cmsg->cmsg_level = SOL_SOCKET; 79 cmsg->cmsg_type = SCM_RIGHTS; 80 *(int *)CMSG_DATA(cmsg) = fd; 81 #endif 82 83 vec.iov_base = &ch; 84 vec.iov_len = 1; 85 msg.msg_iov = &vec; 86 msg.msg_iovlen = 1; 87 88 pfd.fd = sock; 89 pfd.events = POLLOUT; 90 while ((n = sendmsg(sock, &msg, 0)) == -1 && 91 (errno == EAGAIN || errno == EINTR)) { 92 debug3_f("sendmsg(%d): %s", fd, strerror(errno)); 93 (void)poll(&pfd, 1, -1); 94 } 95 if (n == -1) { 96 error_f("sendmsg(%d): %s", fd, strerror(errno)); 97 return -1; 98 } 99 100 if (n != 1) { 101 error_f("sendmsg: expected sent 1 got %zd", n); 102 return -1; 103 } 104 return 0; 105 #else 106 error("%s: file descriptor passing not supported", __func__); 107 return -1; 108 #endif 109 } 110 111 int 112 mm_receive_fd(int sock) 113 { 114 #if defined(HAVE_RECVMSG) && (defined(HAVE_ACCRIGHTS_IN_MSGHDR) || defined(HAVE_CONTROL_IN_MSGHDR)) 115 struct msghdr msg; 116 #ifndef HAVE_ACCRIGHTS_IN_MSGHDR 117 union { 118 struct cmsghdr hdr; 119 char buf[CMSG_SPACE(sizeof(int))]; 120 } cmsgbuf; 121 struct cmsghdr *cmsg; 122 #endif 123 struct iovec vec; 124 ssize_t n; 125 char ch; 126 int fd; 127 struct pollfd pfd; 128 129 memset(&msg, 0, sizeof(msg)); 130 vec.iov_base = &ch; 131 vec.iov_len = 1; 132 msg.msg_iov = &vec; 133 msg.msg_iovlen = 1; 134 #ifdef HAVE_ACCRIGHTS_IN_MSGHDR 135 msg.msg_accrights = (caddr_t)&fd; 136 msg.msg_accrightslen = sizeof(fd); 137 #else 138 memset(&cmsgbuf, 0, sizeof(cmsgbuf)); 139 msg.msg_control = &cmsgbuf.buf; 140 msg.msg_controllen = sizeof(cmsgbuf.buf); 141 #endif 142 143 pfd.fd = sock; 144 pfd.events = POLLIN; 145 while ((n = recvmsg(sock, &msg, 0)) == -1 && 146 (errno == EAGAIN || errno == EINTR)) { 147 debug3_f("recvmsg: %s", strerror(errno)); 148 (void)poll(&pfd, 1, -1); 149 } 150 if (n == -1) { 151 error_f("recvmsg: %s", strerror(errno)); 152 return -1; 153 } 154 155 if (n != 1) { 156 error_f("recvmsg: expected received 1 got %zd", n); 157 return -1; 158 } 159 160 #ifdef HAVE_ACCRIGHTS_IN_MSGHDR 161 if (msg.msg_accrightslen != sizeof(fd)) { 162 error_f("no fd"); 163 return -1; 164 } 165 #else 166 cmsg = CMSG_FIRSTHDR(&msg); 167 if (cmsg == NULL) { 168 error_f("no message header"); 169 return -1; 170 } 171 172 #ifndef BROKEN_CMSG_TYPE 173 if (cmsg->cmsg_type != SCM_RIGHTS) { 174 error_f("expected %d got %d", SCM_RIGHTS, cmsg->cmsg_type); 175 return -1; 176 } 177 #endif 178 fd = (*(int *)CMSG_DATA(cmsg)); 179 #endif 180 return fd; 181 #else 182 error_f("file descriptor passing not supported"); 183 return -1; 184 #endif 185 } 186