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/* $OpenBSD: privsep.c,v 1.14 2007/02/15 15:22:27 stevesk Exp $ */
/*
* Copyright (c) 2004 Henning Brauer <henning@openbsd.org>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF MIND, USE, DATA OR PROFITS, WHETHER IN
* AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
* OF OR IN CONNECTION WITH THE USE, ABUSE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include "dhcpd.h"
#include "privsep.h"
struct buf *
buf_open(size_t len)
{
struct buf *buf;
if ((buf = calloc(1, sizeof(struct buf))) == NULL)
error("buf_open: %m");
if ((buf->buf = malloc(len)) == NULL) {
free(buf);
error("buf_open: %m");
}
buf->size = len;
return (buf);
}
void
buf_add(struct buf *buf, void *data, size_t len)
{
if (len == 0)
return;
if (buf->wpos + len > buf->size)
error("buf_add: %m");
memcpy(buf->buf + buf->wpos, data, len);
buf->wpos += len;
}
void
buf_close(int sock, struct buf *buf)
{
ssize_t n;
do {
n = write(sock, buf->buf + buf->rpos, buf->size - buf->rpos);
if (n == 0) /* connection closed */
error("buf_close (connection closed)");
if (n != -1 && n < buf->size - buf->rpos)
error("buf_close (short write): %m");
} while (n == -1 && (errno == EAGAIN || errno == EINTR));
if (n == -1)
error("buf_close: %m");
free(buf->buf);
free(buf);
}
void
buf_read(int sock, void *buf, size_t nbytes)
{
ssize_t n;
do {
n = read(sock, buf, nbytes);
if (n == 0) { /* connection closed */
debug("buf_read (connection closed)");
exit(1);
}
if (n != -1 && n < nbytes)
error("buf_read (short read): %m");
} while (n == -1 && (errno == EINTR || errno == EAGAIN));
if (n == -1)
error("buf_read: %m");
}
void
dispatch_imsg(int fd)
{
struct imsg_hdr hdr;
char *medium, *reason, *filename,
*servername, *prefix;
size_t medium_len, reason_len, filename_len,
servername_len, prefix_len, totlen;
struct client_lease lease;
int ret, i, optlen;
struct buf *buf;
buf_read(fd, &hdr, sizeof(hdr));
switch (hdr.code) {
case IMSG_SCRIPT_INIT:
if (hdr.len < sizeof(hdr) + sizeof(size_t))
error("corrupted message received");
buf_read(fd, &medium_len, sizeof(medium_len));
if (hdr.len < medium_len + sizeof(size_t) + sizeof(hdr)
+ sizeof(size_t) || medium_len == SIZE_T_MAX)
error("corrupted message received");
if (medium_len > 0) {
if ((medium = calloc(1, medium_len + 1)) == NULL)
error("%m");
buf_read(fd, medium, medium_len);
} else
medium = NULL;
buf_read(fd, &reason_len, sizeof(reason_len));
if (hdr.len < medium_len + reason_len + sizeof(hdr) ||
reason_len == SIZE_T_MAX)
error("corrupted message received");
if (reason_len > 0) {
if ((reason = calloc(1, reason_len + 1)) == NULL)
error("%m");
buf_read(fd, reason, reason_len);
} else
reason = NULL;
priv_script_init(reason, medium);
free(reason);
free(medium);
break;
case IMSG_SCRIPT_WRITE_PARAMS:
bzero(&lease, sizeof lease);
totlen = sizeof(hdr) + sizeof(lease) + sizeof(size_t);
if (hdr.len < totlen)
error("corrupted message received");
buf_read(fd, &lease, sizeof(lease));
buf_read(fd, &filename_len, sizeof(filename_len));
totlen += filename_len + sizeof(size_t);
if (hdr.len < totlen || filename_len == SIZE_T_MAX)
error("corrupted message received");
if (filename_len > 0) {
if ((filename = calloc(1, filename_len + 1)) == NULL)
error("%m");
buf_read(fd, filename, filename_len);
} else
filename = NULL;
buf_read(fd, &servername_len, sizeof(servername_len));
totlen += servername_len + sizeof(size_t);
if (hdr.len < totlen || servername_len == SIZE_T_MAX)
error("corrupted message received");
if (servername_len > 0) {
if ((servername =
calloc(1, servername_len + 1)) == NULL)
error("%m");
buf_read(fd, servername, servername_len);
} else
servername = NULL;
buf_read(fd, &prefix_len, sizeof(prefix_len));
totlen += prefix_len;
if (hdr.len < totlen || prefix_len == SIZE_T_MAX)
error("corrupted message received");
if (prefix_len > 0) {
if ((prefix = calloc(1, prefix_len + 1)) == NULL)
error("%m");
buf_read(fd, prefix, prefix_len);
} else
prefix = NULL;
for (i = 0; i < 256; i++) {
totlen += sizeof(optlen);
if (hdr.len < totlen)
error("corrupted message received");
buf_read(fd, &optlen, sizeof(optlen));
lease.options[i].data = NULL;
lease.options[i].len = optlen;
if (optlen > 0) {
totlen += optlen;
if (hdr.len < totlen || optlen == SIZE_T_MAX)
error("corrupted message received");
lease.options[i].data =
calloc(1, optlen + 1);
if (lease.options[i].data == NULL)
error("%m");
buf_read(fd, lease.options[i].data, optlen);
}
}
lease.server_name = servername;
lease.filename = filename;
priv_script_write_params(prefix, &lease);
free(servername);
free(filename);
free(prefix);
for (i = 0; i < 256; i++)
if (lease.options[i].len > 0)
free(lease.options[i].data);
break;
case IMSG_SCRIPT_GO:
if (hdr.len != sizeof(hdr))
error("corrupted message received");
ret = priv_script_go();
hdr.code = IMSG_SCRIPT_GO_RET;
hdr.len = sizeof(struct imsg_hdr) + sizeof(int);
if ((buf = buf_open(hdr.len)) == NULL)
error("buf_open: %m");
buf_add(buf, &hdr, sizeof(hdr));
buf_add(buf, &ret, sizeof(ret));
buf_close(fd, buf);
break;
default:
error("received unknown message, code %d", hdr.code);
}
}
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