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freebsd-dev/usr.sbin/rtadvd/control.c
Conrad Meyer 96aec9a5e9 rtadvd(8): Fix a typo in full msg receive logic 
Check against the size of the struct, not the pointer.  Previously, a message
with a cm_len between 9 and 23 (inclusive) could cause int msglen to underflow
and read(2) to be invoked with msglen size (implicitly cast to signed),
overrunning the caller-provided buffer.

All users of cm_recv() supply a stack buffer.

On the other hand, the rtadvd control socket appears to only be writable by the
owner, who is probably root.

While here, correct some types to be size_t or ssize_t.

Reported by:	Coverity
CID:		1008477
Security:	unix socket remotes may overflow stack in rtadvd
Sponsored by:	EMC / Isilon Storage Division
2016-05-12 03:37:17 +00:00

493 lines
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/*-
* Copyright (C) 2011 Hiroki Sato <hrs@FreeBSD.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
* BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* $FreeBSD$
*
*/
#include <sys/queue.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/un.h>
#include <sys/uio.h>
#include <net/if.h>
#include <net/if_dl.h>
#include <netinet/in.h>
#include <netinet/icmp6.h>
#include <fcntl.h>
#include <errno.h>
#include <netdb.h>
#include <unistd.h>
#include <poll.h>
#include <signal.h>
#include <string.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <syslog.h>
#include "rtadvd.h"
#include "if.h"
#include "pathnames.h"
#include "control.h"
#define CM_RECV_TIMEOUT 30
int
cm_recv(int fd, char *buf)
{
ssize_t n;
struct ctrl_msg_hdr *cm;
char *msg;
struct pollfd pfds[1];
int i;
syslog(LOG_DEBUG, "<%s> enter, fd=%d", __func__, fd);
memset(buf, 0, CM_MSG_MAXLEN);
cm = (struct ctrl_msg_hdr *)buf;
msg = (char *)buf + sizeof(*cm);
pfds[0].fd = fd;
pfds[0].events = POLLIN;
for (;;) {
i = poll(pfds, sizeof(pfds)/sizeof(pfds[0]),
CM_RECV_TIMEOUT);
if (i == 0)
continue;
if (i < 0) {
syslog(LOG_ERR, "<%s> poll error: %s",
__func__, strerror(errno));
continue;
}
if (pfds[0].revents & POLLIN) {
n = read(fd, cm, sizeof(*cm));
if (n < 0 && errno == EAGAIN) {
syslog(LOG_DEBUG,
"<%s> waiting...", __func__);
continue;
}
break;
}
}
if (n != (ssize_t)sizeof(*cm)) {
syslog(LOG_WARNING,
"<%s> received a too small message.", __func__);
goto cm_recv_err;
}
if (cm->cm_len > CM_MSG_MAXLEN) {
syslog(LOG_WARNING,
"<%s> received a too large message.", __func__);
goto cm_recv_err;
}
if (cm->cm_version != CM_VERSION) {
syslog(LOG_WARNING,
"<%s> version mismatch", __func__);
goto cm_recv_err;
}
if (cm->cm_type >= CM_TYPE_MAX) {
syslog(LOG_WARNING,
"<%s> invalid msg type.", __func__);
goto cm_recv_err;
}
syslog(LOG_DEBUG,
"<%s> ctrl msg received: type=%d", __func__,
cm->cm_type);
if (cm->cm_len > sizeof(*cm)) {
size_t msglen = cm->cm_len - sizeof(*cm);
syslog(LOG_DEBUG,
"<%s> ctrl msg has payload (len=%zu)", __func__,
msglen);
for (;;) {
i = poll(pfds, sizeof(pfds)/sizeof(pfds[0]),
CM_RECV_TIMEOUT);
if (i == 0)
continue;
if (i < 0) {
syslog(LOG_ERR, "<%s> poll error: %s",
__func__, strerror(errno));
continue;
}
if (pfds[0].revents & POLLIN) {
n = read(fd, msg, msglen);
if (n < 0 && errno == EAGAIN) {
syslog(LOG_DEBUG,
"<%s> waiting...", __func__);
continue;
}
}
break;
}
if (n != (ssize_t)msglen) {
syslog(LOG_WARNING,
"<%s> payload size mismatch.", __func__);
goto cm_recv_err;
}
buf[CM_MSG_MAXLEN - 1] = '\0';
}
return (0);
cm_recv_err:
close(fd);
return (-1);
}
int
cm_send(int fd, char *buf)
{
struct iovec iov[2];
int iovcnt;
ssize_t len;
ssize_t iov_len_total;
struct ctrl_msg_hdr *cm;
char *msg;
cm = (struct ctrl_msg_hdr *)buf;
msg = (char *)buf + sizeof(*cm);
iovcnt = 1;
iov[0].iov_base = cm;
iov[0].iov_len = sizeof(*cm);
iov_len_total = iov[0].iov_len;
if (cm->cm_len > sizeof(*cm)) {
iovcnt++;
iov[1].iov_base = msg;
iov[1].iov_len = cm->cm_len - iov[0].iov_len;
iov_len_total += iov[1].iov_len;
}
syslog(LOG_DEBUG,
"<%s> ctrl msg send: type=%d, count=%d, total_len=%zd", __func__,
cm->cm_type, iovcnt, iov_len_total);
len = writev(fd, iov, iovcnt);
syslog(LOG_DEBUG,
"<%s> ctrl msg send: length=%zd", __func__, len);
if (len == -1) {
syslog(LOG_DEBUG,
"<%s> write failed: (%d)%s", __func__, errno,
strerror(errno));
close(fd);
return (-1);
}
syslog(LOG_DEBUG,
"<%s> write length = %zd (actual)", __func__, len);
syslog(LOG_DEBUG,
"<%s> write length = %zd (expected)", __func__, iov_len_total);
if (len != iov_len_total) {
close(fd);
return (-1);
}
return (0);
}
int
csock_accept(struct sockinfo *s)
{
struct sockaddr_un sun;
int flags;
int fd;
sun.sun_len = sizeof(sun);
if ((fd = accept(s->si_fd, (struct sockaddr *)&sun,
(socklen_t *)&sun.sun_len)) == -1) {
if (errno != EWOULDBLOCK && errno != EINTR)
syslog(LOG_WARNING, "<%s> accept ", __func__);
syslog(LOG_WARNING, "<%s> Xaccept: %s", __func__, strerror(errno));
return (-1);
}
if ((flags = fcntl(fd, F_GETFL, 0)) == -1) {
syslog(LOG_WARNING, "<%s> fcntl F_GETFL", __func__);
close(s->si_fd);
return (-1);
}
if ((flags = fcntl(fd, F_SETFL, flags | O_NONBLOCK)) == -1) {
syslog(LOG_WARNING, "<%s> fcntl F_SETFL", __func__);
return (-1);
}
syslog(LOG_DEBUG, "<%s> accept connfd=%d, listenfd=%d", __func__,
fd, s->si_fd);
return (fd);
}
int
csock_close(struct sockinfo *s)
{
close(s->si_fd);
unlink(s->si_name);
syslog(LOG_DEBUG, "<%s> remove %s", __func__, s->si_name);
return (0);
}
int
csock_listen(struct sockinfo *s)
{
if (s->si_fd == -1) {
syslog(LOG_ERR, "<%s> listen failed", __func__);
return (-1);
}
if (listen(s->si_fd, SOCK_BACKLOG) == -1) {
syslog(LOG_ERR, "<%s> listen failed", __func__);
return (-1);
}
return (0);
}
int
csock_open(struct sockinfo *s, mode_t mode)
{
int flags;
struct sockaddr_un sun;
mode_t old_umask;
if (s == NULL) {
syslog(LOG_ERR, "<%s> internal error.", __func__);
exit(1);
}
if (s->si_name == NULL)
s->si_name = _PATH_CTRL_SOCK;
if ((s->si_fd = socket(PF_UNIX, SOCK_STREAM, 0)) == -1) {
syslog(LOG_ERR,
"<%s> cannot open control socket", __func__);
return (-1);
}
memset(&sun, 0, sizeof(sun));
sun.sun_family = AF_UNIX;
sun.sun_len = sizeof(sun);
strlcpy(sun.sun_path, s->si_name, sizeof(sun.sun_path));
if (unlink(s->si_name) == -1)
if (errno != ENOENT) {
syslog(LOG_ERR,
"<%s> unlink %s", __func__, s->si_name);
close(s->si_fd);
return (-1);
}
old_umask = umask(S_IXUSR|S_IXGRP|S_IXOTH);
if (bind(s->si_fd, (struct sockaddr *)&sun, sizeof(sun)) == -1) {
syslog(LOG_ERR,
"<%s> bind failed: %s", __func__, s->si_name);
close(s->si_fd);
umask(old_umask);
return (-1);
}
umask(old_umask);
if (chmod(s->si_name, mode) == -1) {
syslog(LOG_ERR,
"<%s> chmod failed: %s", __func__, s->si_name);
goto csock_open_err;
}
if ((flags = fcntl(s->si_fd, F_GETFL, 0)) == -1) {
syslog(LOG_ERR,
"<%s> fcntl F_GETFL failed: %s", __func__, s->si_name);
goto csock_open_err;
}
if ((flags = fcntl(s->si_fd, F_SETFL, flags | O_NONBLOCK)) == -1) {
syslog(LOG_ERR,
"<%s> fcntl F_SETFL failed: %s", __func__, s->si_name);
goto csock_open_err;
}
return (s->si_fd);
csock_open_err:
close(s->si_fd);
unlink(s->si_name);
return (-1);
}
struct ctrl_msg_pl *
cm_bin2pl(char *str, struct ctrl_msg_pl *cp)
{
size_t len;
size_t *lenp;
char *p;
memset(cp, 0, sizeof(*cp));
p = str;
lenp = (size_t *)p;
len = *lenp++;
p = (char *)lenp;
syslog(LOG_DEBUG, "<%s> len(ifname) = %zu", __func__, len);
if (len > 0) {
cp->cp_ifname = malloc(len + 1);
if (cp->cp_ifname == NULL) {
syslog(LOG_ERR, "<%s> malloc", __func__);
exit(1);
}
memcpy(cp->cp_ifname, p, len);
cp->cp_ifname[len] = '\0';
p += len;
}
lenp = (size_t *)p;
len = *lenp++;
p = (char *)lenp;
syslog(LOG_DEBUG, "<%s> len(key) = %zu", __func__, len);
if (len > 0) {
cp->cp_key = malloc(len + 1);
if (cp->cp_key == NULL) {
syslog(LOG_ERR, "<%s> malloc", __func__);
exit(1);
}
memcpy(cp->cp_key, p, len);
cp->cp_key[len] = '\0';
p += len;
}
lenp = (size_t *)p;
len = *lenp++;
p = (char *)lenp;
syslog(LOG_DEBUG, "<%s> len(val) = %zu", __func__, len);
if (len > 0) {
cp->cp_val = malloc(len + 1);
if (cp->cp_val == NULL) {
syslog(LOG_ERR, "<%s> malloc", __func__);
exit(1);
}
memcpy(cp->cp_val, p, len);
cp->cp_val[len] = '\0';
cp->cp_val_len = len;
} else
cp->cp_val_len = 0;
return (cp);
}
size_t
cm_pl2bin(char *str, struct ctrl_msg_pl *cp)
{
size_t len;
size_t *lenp;
char *p;
struct ctrl_msg_hdr *cm;
len = sizeof(size_t);
if (cp->cp_ifname != NULL)
len += strlen(cp->cp_ifname);
len += sizeof(size_t);
if (cp->cp_key != NULL)
len += strlen(cp->cp_key);
len += sizeof(size_t);
if (cp->cp_val != NULL && cp->cp_val_len > 0)
len += cp->cp_val_len;
if (len > CM_MSG_MAXLEN - sizeof(*cm)) {
syslog(LOG_DEBUG, "<%s> msg too long (len=%zu)",
__func__, len);
return (0);
}
syslog(LOG_DEBUG, "<%s> msglen=%zu", __func__, len);
memset(str, 0, len);
p = str;
lenp = (size_t *)p;
if (cp->cp_ifname != NULL) {
*lenp++ = strlen(cp->cp_ifname);
p = (char *)lenp;
memcpy(p, cp->cp_ifname, strlen(cp->cp_ifname));
p += strlen(cp->cp_ifname);
} else {
*lenp++ = '\0';
p = (char *)lenp;
}
lenp = (size_t *)p;
if (cp->cp_key != NULL) {
*lenp++ = strlen(cp->cp_key);
p = (char *)lenp;
memcpy(p, cp->cp_key, strlen(cp->cp_key));
p += strlen(cp->cp_key);
} else {
*lenp++ = '\0';
p = (char *)lenp;
}
lenp = (size_t *)p;
if (cp->cp_val != NULL && cp->cp_val_len > 0) {
*lenp++ = cp->cp_val_len;
p = (char *)lenp;
memcpy(p, cp->cp_val, cp->cp_val_len);
p += cp->cp_val_len;
} else {
*lenp++ = '\0';
p = (char *)lenp;
}
return (len);
}
size_t
cm_str2bin(char *bin, void *str, size_t len)
{
struct ctrl_msg_hdr *cm;
syslog(LOG_DEBUG, "<%s> enter", __func__);
if (len > CM_MSG_MAXLEN - sizeof(*cm)) {
syslog(LOG_DEBUG, "<%s> msg too long (len=%zu)",
__func__, len);
return (0);
}
syslog(LOG_DEBUG, "<%s> msglen=%zu", __func__, len);
memcpy(bin, (char *)str, len);
return (len);
}
void *
cm_bin2str(char *bin, void *str, size_t len)
{
syslog(LOG_DEBUG, "<%s> enter", __func__);
memcpy((char *)str, bin, len);
return (str);
}
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