| 1 | /* $OpenBSD: src/sbin/dhclient/privsep.c,v 1.16 2011/04/04 11:14:52 krw Exp $ */ |
| 2 | |
| 3 | /* |
| 4 | * Copyright (c) 2004 Henning Brauer <henning@openbsd.org> |
| 5 | * |
| 6 | * Permission to use, copy, modify, and distribute this software for any |
| 7 | * purpose with or without fee is hereby granted, provided that the above |
| 8 | * copyright notice and this permission notice appear in all copies. |
| 9 | * |
| 10 | * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES |
| 11 | * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF |
| 12 | * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR |
| 13 | * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES |
| 14 | * WHATSOEVER RESULTING FROM LOSS OF MIND, USE, DATA OR PROFITS, WHETHER IN |
| 15 | * AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT |
| 16 | * OF OR IN CONNECTION WITH THE USE, ABUSE OR PERFORMANCE OF THIS SOFTWARE. |
| 17 | */ |
| 18 | |
| 19 | #include "dhcpd.h" |
| 20 | #include "privsep.h" |
| 21 | |
| 22 | struct buf * |
| 23 | buf_open(size_t len) |
| 24 | { |
| 25 | struct buf *buf; |
| 26 | |
| 27 | if ((buf = calloc(1, sizeof(struct buf))) == NULL) |
| 28 | error("buf_open: %m"); |
| 29 | if ((buf->buf = malloc(len)) == NULL) { |
| 30 | free(buf); |
| 31 | error("buf_open: %m"); |
| 32 | } |
| 33 | buf->size = len; |
| 34 | |
| 35 | return (buf); |
| 36 | } |
| 37 | |
| 38 | void |
| 39 | buf_add(struct buf *buf, void *data, size_t len) |
| 40 | { |
| 41 | if (len == 0) |
| 42 | return; |
| 43 | |
| 44 | if (buf->wpos + len > buf->size) |
| 45 | error("buf_add: %m"); |
| 46 | |
| 47 | memcpy(buf->buf + buf->wpos, data, len); |
| 48 | buf->wpos += len; |
| 49 | } |
| 50 | |
| 51 | void |
| 52 | buf_close(int sock, struct buf *buf) |
| 53 | { |
| 54 | ssize_t n; |
| 55 | |
| 56 | do { |
| 57 | n = write(sock, buf->buf + buf->rpos, buf->size - buf->rpos); |
| 58 | if (n == 0) /* connection closed */ |
| 59 | error("buf_close (connection closed)"); |
| 60 | if (n != -1 && n < buf->size - buf->rpos) |
| 61 | error("buf_close (short write): %m"); |
| 62 | |
| 63 | } while (n == -1 && (errno == EAGAIN || errno == EINTR)); |
| 64 | |
| 65 | if (n == -1) |
| 66 | error("buf_close: %m"); |
| 67 | |
| 68 | free(buf->buf); |
| 69 | free(buf); |
| 70 | } |
| 71 | |
| 72 | void |
| 73 | buf_read(int sock, void *buf, size_t nbytes) |
| 74 | { |
| 75 | ssize_t n; |
| 76 | |
| 77 | do { |
| 78 | n = read(sock, buf, nbytes); |
| 79 | if (n == 0) { /* connection closed */ |
| 80 | #ifdef DEBUG |
| 81 | debug("buf_read (connection closed)"); |
| 82 | #endif |
| 83 | exit(1); |
| 84 | } |
| 85 | if (n != -1 && n < nbytes) |
| 86 | error("buf_read (short read): %m"); |
| 87 | } while (n == -1 && (errno == EINTR || errno == EAGAIN)); |
| 88 | |
| 89 | if (n == -1) |
| 90 | error("buf_read: %m"); |
| 91 | } |
| 92 | |
| 93 | void |
| 94 | dispatch_imsg(int fd) |
| 95 | { |
| 96 | struct imsg_hdr hdr; |
| 97 | char *reason, *filename, |
| 98 | *servername, *prefix; |
| 99 | size_t reason_len, filename_len, |
| 100 | servername_len, prefix_len, totlen; |
| 101 | struct client_lease lease; |
| 102 | int ret, i, optlen; |
| 103 | struct buf *buf; |
| 104 | |
| 105 | buf_read(fd, &hdr, sizeof(hdr)); |
| 106 | |
| 107 | switch (hdr.code) { |
| 108 | case IMSG_SCRIPT_INIT: |
| 109 | if (hdr.len < sizeof(hdr) + sizeof(size_t)) |
| 110 | error("corrupted message received"); |
| 111 | buf_read(fd, &reason_len, sizeof(reason_len)); |
| 112 | if (hdr.len < reason_len + sizeof(hdr) + sizeof(size_t) || |
| 113 | reason_len == SIZE_T_MAX) |
| 114 | error("corrupted message received"); |
| 115 | if (reason_len > 0) { |
| 116 | if ((reason = calloc(1, reason_len + 1)) == NULL) |
| 117 | error("%m"); |
| 118 | buf_read(fd, reason, reason_len); |
| 119 | } else |
| 120 | reason = NULL; |
| 121 | |
| 122 | priv_script_init(reason); |
| 123 | free(reason); |
| 124 | break; |
| 125 | case IMSG_SCRIPT_WRITE_PARAMS: |
| 126 | bzero(&lease, sizeof lease); |
| 127 | totlen = sizeof(hdr) + sizeof(lease) + sizeof(size_t); |
| 128 | if (hdr.len < totlen) |
| 129 | error("corrupted message received"); |
| 130 | buf_read(fd, &lease, sizeof(lease)); |
| 131 | |
| 132 | buf_read(fd, &filename_len, sizeof(filename_len)); |
| 133 | totlen += filename_len + sizeof(size_t); |
| 134 | if (hdr.len < totlen || filename_len == SIZE_T_MAX) |
| 135 | error("corrupted message received"); |
| 136 | if (filename_len > 0) { |
| 137 | if ((filename = calloc(1, filename_len + 1)) == NULL) |
| 138 | error("%m"); |
| 139 | buf_read(fd, filename, filename_len); |
| 140 | } else |
| 141 | filename = NULL; |
| 142 | |
| 143 | buf_read(fd, &servername_len, sizeof(servername_len)); |
| 144 | totlen += servername_len + sizeof(size_t); |
| 145 | if (hdr.len < totlen || servername_len == SIZE_T_MAX) |
| 146 | error("corrupted message received"); |
| 147 | if (servername_len > 0) { |
| 148 | if ((servername = |
| 149 | calloc(1, servername_len + 1)) == NULL) |
| 150 | error("%m"); |
| 151 | buf_read(fd, servername, servername_len); |
| 152 | } else |
| 153 | servername = NULL; |
| 154 | |
| 155 | buf_read(fd, &prefix_len, sizeof(prefix_len)); |
| 156 | totlen += prefix_len; |
| 157 | if (hdr.len < totlen || prefix_len == SIZE_T_MAX) |
| 158 | error("corrupted message received"); |
| 159 | if (prefix_len > 0) { |
| 160 | if ((prefix = calloc(1, prefix_len + 1)) == NULL) |
| 161 | error("%m"); |
| 162 | buf_read(fd, prefix, prefix_len); |
| 163 | } else |
| 164 | prefix = NULL; |
| 165 | |
| 166 | for (i = 0; i < 256; i++) { |
| 167 | totlen += sizeof(optlen); |
| 168 | if (hdr.len < totlen) |
| 169 | error("corrupted message received"); |
| 170 | buf_read(fd, &optlen, sizeof(optlen)); |
| 171 | lease.options[i].data = NULL; |
| 172 | lease.options[i].len = optlen; |
| 173 | if (optlen > 0) { |
| 174 | totlen += optlen; |
| 175 | if (hdr.len < totlen || optlen == SIZE_T_MAX) |
| 176 | error("corrupted message received"); |
| 177 | lease.options[i].data = |
| 178 | calloc(1, optlen + 1); |
| 179 | if (lease.options[i].data == NULL) |
| 180 | error("%m"); |
| 181 | buf_read(fd, lease.options[i].data, optlen); |
| 182 | } |
| 183 | } |
| 184 | lease.server_name = servername; |
| 185 | lease.filename = filename; |
| 186 | |
| 187 | priv_script_write_params(prefix, &lease); |
| 188 | |
| 189 | free(servername); |
| 190 | free(filename); |
| 191 | free(prefix); |
| 192 | for (i = 0; i < 256; i++) |
| 193 | if (lease.options[i].len > 0) |
| 194 | free(lease.options[i].data); |
| 195 | break; |
| 196 | case IMSG_SCRIPT_GO: |
| 197 | if (hdr.len != sizeof(hdr)) |
| 198 | error("corrupted message received"); |
| 199 | |
| 200 | ret = priv_script_go(); |
| 201 | |
| 202 | hdr.code = IMSG_SCRIPT_GO_RET; |
| 203 | hdr.len = sizeof(struct imsg_hdr) + sizeof(int); |
| 204 | if ((buf = buf_open(hdr.len)) == NULL) |
| 205 | error("buf_open: %m"); |
| 206 | buf_add(buf, &hdr, sizeof(hdr)); |
| 207 | buf_add(buf, &ret, sizeof(ret)); |
| 208 | buf_close(fd, buf); |
| 209 | break; |
| 210 | default: |
| 211 | error("received unknown message, code %d", hdr.code); |
| 212 | } |
| 213 | } |