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privsep-root.c
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1223 lines (1067 loc) · 27.1 KB
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/* SPDX-License-Identifier: BSD-2-Clause */
/*
* Privilege Separation for dhcpcd, privileged proxy
* Copyright (c) 2006-2025 Roy Marples <roy@marples.name>
* 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 AUTHOR 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 AUTHOR 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.
*/
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <assert.h>
#include <errno.h>
#include <fcntl.h>
#include <pwd.h>
#include <signal.h>
#include <stddef.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "auth.h"
#include "common.h"
#include "dev.h"
#include "dhcpcd.h"
#include "dhcp6.h"
#include "eloop.h"
#include "if.h"
#include "ipv6nd.h"
#include "logerr.h"
#include "privsep.h"
#include "sa.h"
#include "script.h"
__CTASSERT(sizeof(ioctl_request_t) <= sizeof(unsigned long));
struct psr_error
{
ssize_t psr_result;
int psr_errno;
char psr_pad[sizeof(ssize_t) - sizeof(int)];
size_t psr_datalen;
};
struct psr_ctx {
struct dhcpcd_ctx *psr_ctx;
struct psr_error psr_error;
size_t psr_datalen;
void *psr_data;
bool psr_mallocdata;
};
static ssize_t
ps_root_readerrorcb(struct psr_ctx *pc)
{
struct dhcpcd_ctx *ctx = pc->psr_ctx;
int fd = PS_ROOT_FD(ctx);
struct psr_error *psr_error = &pc->psr_error;
struct iovec iov[] = {
{ .iov_base = psr_error, .iov_len = sizeof(*psr_error) },
{ .iov_base = pc->psr_data, .iov_len = pc->psr_datalen },
};
struct msghdr msg = { .msg_iov = iov, .msg_iovlen = __arraycount(iov) };
ssize_t len;
#define PSR_ERROR(e) \
do { \
psr_error->psr_errno = (e); \
goto error; \
} while (0 /* CONSTCOND */)
if (eloop_waitfd(fd) == -1)
PSR_ERROR(errno);
if (!pc->psr_mallocdata)
goto recv;
/* We peek at the psr_error structure to tell us how much of a buffer
* we need to read the whole packet. */
msg.msg_iovlen--;
len = recvmsg(fd, &msg, MSG_PEEK | MSG_WAITALL);
if (len == -1)
PSR_ERROR(errno);
/* After this point, we MUST do another recvmsg even on a failure
* to remove the message after peeking. */
if ((size_t)len < sizeof(*psr_error)) {
/* We can't use the header to work out buffers, so
* remove the message and bail. */
(void)recvmsg(fd, &msg, MSG_WAITALL);
PSR_ERROR(EINVAL);
}
/* No data to read? Unlikely but ... */
if (psr_error->psr_datalen == 0)
goto recv;
pc->psr_data = malloc(psr_error->psr_datalen);
if (pc->psr_data != NULL) {
iov[1].iov_base = pc->psr_data;
iov[1].iov_len = psr_error->psr_datalen;
msg.msg_iovlen++;
}
recv:
len = recvmsg(fd, &msg, MSG_WAITALL);
if (len == -1)
PSR_ERROR(errno);
else if ((size_t)len < sizeof(*psr_error))
PSR_ERROR(EINVAL);
else if (msg.msg_flags & MSG_TRUNC)
PSR_ERROR(ENOBUFS);
else if ((size_t)len != sizeof(*psr_error) + psr_error->psr_datalen) {
#ifdef PRIVSEP_DEBUG
logerrx("%s: recvmsg returned %zd, expecting %zu", __func__,
len, sizeof(*psr_error) + psr_error->psr_datalen);
#endif
PSR_ERROR(EBADMSG);
}
return len;
error:
psr_error->psr_result = -1;
if (pc->psr_mallocdata && pc->psr_data != NULL) {
free(pc->psr_data);
pc->psr_data = NULL;
}
return -1;
}
ssize_t
ps_root_readerror(struct dhcpcd_ctx *ctx, void *data, size_t len)
{
struct psr_ctx pc = {
.psr_ctx = ctx,
.psr_data = data,
.psr_datalen = len,
.psr_mallocdata = false
};
ps_root_readerrorcb(&pc);
errno = pc.psr_error.psr_errno;
return pc.psr_error.psr_result;
}
ssize_t
ps_root_mreaderror(struct dhcpcd_ctx *ctx, void **data, size_t *len)
{
struct psr_ctx pc = {
.psr_ctx = ctx,
.psr_data = NULL,
.psr_datalen = 0,
.psr_mallocdata = true
};
ps_root_readerrorcb(&pc);
errno = pc.psr_error.psr_errno;
*data = pc.psr_data;
*len = pc.psr_error.psr_datalen;
return pc.psr_error.psr_result;
}
static ssize_t
ps_root_writeerror(struct dhcpcd_ctx *ctx, ssize_t result,
void *data, size_t len)
{
struct psr_error psr = {
.psr_result = result,
.psr_errno = errno,
.psr_datalen = len,
};
struct iovec iov[] = {
{ .iov_base = &psr, .iov_len = sizeof(psr) },
{ .iov_base = data, .iov_len = len },
};
struct msghdr msg = { .msg_iov = iov, .msg_iovlen = __arraycount(iov) };
ssize_t err;
int fd = PS_ROOT_FD(ctx);
#ifdef PRIVSEP_DEBUG
logdebugx("%s: result %zd errno %d", __func__, result, errno);
#endif
if (len == 0)
msg.msg_iovlen = 1;
err = sendmsg(fd, &msg, MSG_EOR);
/* Error sending the message? Try sending the error of sending. */
if (err == -1 && errno != EPIPE) {
logerr("%s: result=%zd, data=%p, len=%zu",
__func__, result, data, len);
psr.psr_result = err;
psr.psr_errno = errno;
psr.psr_datalen = 0;
msg.msg_iovlen = 1;
err = sendmsg(fd, &msg, MSG_EOR);
}
return err;
}
static ssize_t
ps_root_doioctl(unsigned long req, void *data, size_t len)
{
int s, err;
/* Only allow these ioctls */
switch(req) {
#ifdef SIOCAIFADDR
case SIOCAIFADDR: /* FALLTHROUGH */
case SIOCDIFADDR: /* FALLTHROUGH */
#endif
#ifdef SIOCSIFHWADDR
case SIOCSIFHWADDR: /* FALLTHROUGH */
#endif
#ifdef SIOCGIFPRIORITY
case SIOCGIFPRIORITY: /* FALLTHROUGH */
#endif
case SIOCSIFFLAGS: /* FALLTHROUGH */
case SIOCGIFMTU:
break;
default:
errno = EPERM;
return -1;
}
s = xsocket(PF_INET, SOCK_DGRAM, 0);
if (s != -1)
#ifdef IOCTL_REQUEST_TYPE
{
ioctl_request_t reqt;
memcpy(&reqt, &req, sizeof(reqt));
err = ioctl(s, reqt, data, len);
}
#else
err = ioctl(s, req, data, len);
#endif
else
err = -1;
if (s != -1)
close(s);
return err;
}
static ssize_t
ps_root_run_script(struct dhcpcd_ctx *ctx, const void *data, size_t len)
{
const char *envbuf = data;
char * const argv[] = { ctx->script, NULL };
pid_t pid;
int status;
if (len == 0)
return 0;
if (script_buftoenv(ctx, UNCONST(envbuf), len) == NULL)
return -1;
pid = script_exec(argv, ctx->script_env);
if (pid == -1)
return -1;
/* Wait for the script to finish */
while (waitpid(pid, &status, 0) == -1) {
if (errno != EINTR) {
logerr(__func__);
status = 0;
break;
}
}
return status;
}
static bool
ps_root_validpath(const struct dhcpcd_ctx *ctx, uint16_t cmd, const char *path)
{
/* Avoid a previous directory attack to avoid /proc/../
* dhcpcd should never use a path with double dots. */
if (strstr(path, "..") != NULL)
return false;
if (cmd == PS_READFILE) {
#ifdef EMBEDDED_CONFIG
if (strcmp(ctx->cffile, EMBEDDED_CONFIG) == 0)
return true;
#endif
if (strcmp(ctx->cffile, path) == 0)
return true;
}
if (strncmp(DBDIR, path, strlen(DBDIR)) == 0)
return true;
if (strncmp(RUNDIR, path, strlen(RUNDIR)) == 0)
return true;
#ifdef __linux__
if (strncmp("/proc/net/", path, strlen("/proc/net/")) == 0 ||
strncmp("/proc/sys/net/", path, strlen("/proc/sys/net/")) == 0 ||
strncmp("/sys/class/net/", path, strlen("/sys/class/net/")) == 0)
return true;
#endif
errno = EPERM;
return false;
}
static ssize_t
ps_root_dowritefile(const struct dhcpcd_ctx *ctx,
mode_t mode, void *data, size_t len)
{
char *file = data, *nc;
nc = memchr(file, '\0', len);
if (nc == NULL) {
errno = EINVAL;
return -1;
}
if (!ps_root_validpath(ctx, PS_WRITEFILE, file))
return -1;
nc++;
return writefile(file, mode, nc, len - (size_t)(nc - file));
}
#ifdef AUTH
static ssize_t
ps_root_monordm(uint64_t *rdm, size_t len)
{
if (len != sizeof(*rdm)) {
errno = EINVAL;
return -1;
}
return auth_get_rdm_monotonic(rdm);
}
#endif
#ifdef PRIVSEP_GETIFADDRS
#define IFA_NADDRS 4
static ssize_t
ps_root_dogetifaddrs(void **rdata, size_t *rlen)
{
struct ifaddrs *ifaddrs, *ifa;
size_t len;
uint8_t *buf, *sap;
socklen_t salen;
if (getifaddrs(&ifaddrs) == -1)
return -1;
if (ifaddrs == NULL) {
*rdata = NULL;
*rlen = 0;
return 0;
}
/* Work out the buffer length required.
* Ensure everything is aligned correctly, which does
* create a larger buffer than what is needed to send,
* but makes creating the same structure in the client
* much easier. */
len = 0;
for (ifa = ifaddrs; ifa != NULL; ifa = ifa->ifa_next) {
len += ALIGN(sizeof(*ifa));
len += ALIGN(IFNAMSIZ);
len += ALIGN(sizeof(salen) * IFA_NADDRS);
if (ifa->ifa_addr != NULL)
len += ALIGN(sa_len(ifa->ifa_addr));
if (ifa->ifa_netmask != NULL)
len += ALIGN(sa_len(ifa->ifa_netmask));
if (ifa->ifa_broadaddr != NULL)
len += ALIGN(sa_len(ifa->ifa_broadaddr));
#ifdef BSD
/*
* On BSD we need to carry ifa_data so we can access
* if_data->ifi_link_state
*/
if (ifa->ifa_addr != NULL &&
ifa->ifa_addr->sa_family == AF_LINK)
len += ALIGN(sizeof(struct if_data));
#endif
}
/* Use calloc to set everything to zero.
* This satisfies memory sanitizers because don't write
* where we don't need to. */
buf = calloc(1, len);
if (buf == NULL) {
freeifaddrs(ifaddrs);
return -1;
}
*rdata = buf;
*rlen = len;
for (ifa = ifaddrs; ifa != NULL; ifa = ifa->ifa_next) {
memcpy(buf, ifa, sizeof(*ifa));
buf += ALIGN(sizeof(*ifa));
strlcpy((char *)buf, ifa->ifa_name, IFNAMSIZ);
buf += ALIGN(IFNAMSIZ);
sap = buf;
buf += ALIGN(sizeof(salen) * IFA_NADDRS);
#define COPYINSA(addr) \
do { \
if ((addr) != NULL) \
salen = sa_len((addr)); \
else \
salen = 0; \
if (salen != 0) { \
memcpy(sap, &salen, sizeof(salen)); \
memcpy(buf, (addr), salen); \
buf += ALIGN(salen); \
} \
sap += sizeof(salen); \
} while (0 /*CONSTCOND */)
COPYINSA(ifa->ifa_addr);
COPYINSA(ifa->ifa_netmask);
COPYINSA(ifa->ifa_broadaddr);
#ifdef BSD
if (ifa->ifa_addr != NULL &&
ifa->ifa_addr->sa_family == AF_LINK)
{
salen = (socklen_t)sizeof(struct if_data);
memcpy(buf, ifa->ifa_data, salen);
buf += ALIGN(salen);
} else
#endif
salen = 0;
memcpy(sap, &salen, sizeof(salen));
}
freeifaddrs(ifaddrs);
return 0;
}
#endif
static ssize_t
ps_root_recvmsgcb(void *arg, struct ps_msghdr *psm, struct msghdr *msg)
{
struct dhcpcd_ctx *ctx = arg;
uint16_t cmd;
struct ps_process *psp;
struct iovec *iov = msg->msg_iov;
void *data = iov->iov_base, *rdata = NULL;
size_t len = iov->iov_len, rlen = 0;
uint8_t buf[PS_BUFLEN];
time_t mtime;
ssize_t err;
bool free_rdata = false;
cmd = (uint16_t)(psm->ps_cmd & ~(PS_START | PS_STOP));
psp = ps_findprocess(ctx, &psm->ps_id);
#ifdef PRIVSEP_DEBUG
logerrx("%s: IN cmd %x, psp %p", __func__, psm->ps_cmd, psp);
#endif
if (psp != NULL) {
if (psm->ps_cmd & PS_STOP) {
return ps_stopprocess(psp);
} else if (psm->ps_cmd & PS_START) {
/* Process has already started .... */
logdebugx("%s%sprocess %s already started on pid %d",
psp->psp_ifname,
psp->psp_ifname[0] != '\0' ? ": " : "",
psp->psp_name, psp->psp_pid);
return 0;
}
err = ps_sendpsmmsg(ctx, psp->psp_fd, psm, msg);
if (err == -1) {
logerr("%s: failed to send message to pid %d",
__func__, psp->psp_pid);
ps_freeprocess(psp);
}
return 0;
}
if (psm->ps_cmd & PS_STOP && psp == NULL)
return 0;
switch (cmd) {
#ifdef INET
#ifdef ARP
case PS_BPF_ARP: /* FALLTHROUGH */
#endif
case PS_BPF_BOOTP:
return ps_bpf_cmd(ctx, psm, msg);
#endif
#ifdef INET
case PS_BOOTP:
return ps_inet_cmd(ctx, psm, msg);
#endif
#ifdef INET6
#ifdef DHCP6
case PS_DHCP6: /* FALLTHROUGH */
#endif
case PS_ND:
return ps_inet_cmd(ctx, psm, msg);
#endif
default:
break;
}
assert(msg->msg_iovlen == 0 || msg->msg_iovlen == 1);
/* Reset errno */
errno = 0;
switch (psm->ps_cmd) {
case PS_IOCTL:
err = ps_root_doioctl(psm->ps_flags, data, len);
if (err != -1) {
rdata = data;
rlen = len;
}
break;
case PS_SCRIPT:
err = ps_root_run_script(ctx, data, len);
break;
case PS_STOPPROCS:
ctx->options |= DHCPCD_EXITING;
TAILQ_FOREACH(psp, &ctx->ps_processes, next) {
if (psp != ctx->ps_root)
ps_stopprocess(psp);
}
err = ps_stopwait(ctx);
break;
case PS_UNLINK:
if (!ps_root_validpath(ctx, psm->ps_cmd, data)) {
err = -1;
break;
}
err = unlink(data);
break;
case PS_READFILE:
if (!ps_root_validpath(ctx, psm->ps_cmd, data)) {
err = -1;
break;
}
err = readfile(data, buf, sizeof(buf));
if (err != -1) {
rdata = buf;
rlen = (size_t)err;
}
break;
case PS_WRITEFILE:
err = ps_root_dowritefile(ctx, (mode_t)psm->ps_flags,
data, len);
break;
case PS_FILEMTIME:
err = filemtime(data, &mtime);
if (err != -1) {
rdata = &mtime;
rlen = sizeof(mtime);
}
break;
case PS_LOGREOPEN:
err = logopen(ctx->logfile);
break;
#ifdef AUTH
case PS_AUTH_MONORDM:
err = ps_root_monordm(data, len);
if (err != -1) {
rdata = data;
rlen = len;
}
break;
#endif
#ifdef PRIVSEP_GETIFADDRS
case PS_GETIFADDRS:
err = ps_root_dogetifaddrs(&rdata, &rlen);
free_rdata = true;
break;
#endif
#ifdef PLUGIN_DEV
case PS_DEV_INITTED:
err = dev_initialised(ctx, data);
break;
case PS_DEV_LISTENING:
err = dev_listening(ctx);
break;
#endif
default:
err = ps_root_os(ctx, psm, msg, &rdata, &rlen, &free_rdata);
break;
}
err = ps_root_writeerror(ctx, err, rdata, rlen);
if (free_rdata)
free(rdata);
return err;
}
/* Receive from state engine, do an action. */
static void
ps_root_recvmsg(void *arg, unsigned short events)
{
struct ps_process *psp = arg;
if (ps_recvpsmsg(psp->psp_ctx, psp->psp_fd, events,
ps_root_recvmsgcb, psp->psp_ctx) == -1)
logerr(__func__);
}
#ifdef PLUGIN_DEV
static int
ps_root_handleinterface(void *arg, int action, const char *ifname)
{
struct dhcpcd_ctx *ctx = arg;
unsigned long flag;
if (action == 1)
flag = PS_DEV_IFADDED;
else if (action == -1)
flag = PS_DEV_IFREMOVED;
else if (action == 0)
flag = PS_DEV_IFUPDATED;
else {
errno = EINVAL;
return -1;
}
return (int)ps_sendcmd(ctx, ctx->ps_data_fd, PS_DEV_IFCMD,
flag, ifname, strlen(ifname) + 1);
}
#endif
static int
ps_root_startcb(struct ps_process *psp)
{
struct dhcpcd_ctx *ctx = psp->psp_ctx;
if (ctx->options & DHCPCD_MANAGER)
setproctitle("[privileged proxy]");
else
setproctitle("[privileged proxy] %s%s%s",
ctx->ifv[0],
ctx->options & DHCPCD_IPV4 ? " [ip4]" : "",
ctx->options & DHCPCD_IPV6 ? " [ip6]" : "");
ctx->options |= DHCPCD_PRIVSEPROOT;
if (if_opensockets(ctx) == -1)
logerr("%s: if_opensockets", __func__);
/* Open network sockets for sending.
* This is a small bit wasteful for non sandboxed OS's
* but makes life very easy for unicasting DHCPv6 in non manager
* mode as we no longer care about address selection.
* We can't call shutdown SHUT_RD on the socket because it's
* not connected. All we can do is try and set a zero sized
* receive buffer and just let it overflow.
* Reading from it just to drain it is a waste of CPU time. */
#ifdef INET
if (ctx->options & DHCPCD_IPV4) {
int buflen = 1;
ctx->udp_wfd = xsocket(PF_INET,
SOCK_RAW | SOCK_CXNB, IPPROTO_UDP);
if (ctx->udp_wfd == -1)
logerr("%s: dhcp_openraw", __func__);
else if (setsockopt(ctx->udp_wfd, SOL_SOCKET, SO_RCVBUF,
&buflen, sizeof(buflen)) == -1)
logerr("%s: setsockopt SO_RCVBUF DHCP", __func__);
}
#endif
#ifdef INET6
if (ctx->options & DHCPCD_IPV6) {
int buflen = 1;
ctx->nd_fd = ipv6nd_open(false);
if (ctx->nd_fd == -1)
logerr("%s: ipv6nd_open", __func__);
else if (setsockopt(ctx->nd_fd, SOL_SOCKET, SO_RCVBUF,
&buflen, sizeof(buflen)) == -1)
logerr("%s: setsockopt SO_RCVBUF ND", __func__);
}
#endif
#ifdef DHCP6
if (ctx->options & DHCPCD_IPV6) {
int buflen = 1;
ctx->dhcp6_wfd = dhcp6_openraw();
if (ctx->dhcp6_wfd == -1)
logerr("%s: dhcp6_openraw", __func__);
else if (setsockopt(ctx->dhcp6_wfd, SOL_SOCKET, SO_RCVBUF,
&buflen, sizeof(buflen)) == -1)
logerr("%s: setsockopt SO_RCVBUF DHCP6", __func__);
}
#endif
#ifdef PLUGIN_DEV
/* Start any dev listening plugin which may want to
* change the interface name provided by the kernel */
if ((ctx->options & (DHCPCD_MANAGER | DHCPCD_DEV)) ==
(DHCPCD_MANAGER | DHCPCD_DEV))
dev_start(ctx, ps_root_handleinterface);
#endif
return 0;
}
void
ps_root_signalcb(int sig, void *arg)
{
struct dhcpcd_ctx *ctx = arg;
int status;
pid_t pid;
const char *ifname, *name;
struct ps_process *psp;
if (sig != SIGCHLD)
return;
while ((pid = waitpid(-1, &status, WNOHANG)) > 0) {
psp = ps_findprocesspid(ctx, pid);
if (psp != NULL) {
ifname = psp->psp_ifname;
name = psp->psp_name;
} else {
/* Ignore logging the double fork */
if (ctx->options & DHCPCD_LAUNCHER)
continue;
ifname = "";
name = "unknown process";
}
if (WIFEXITED(status) && WEXITSTATUS(status) != 0)
logerrx("%s%s%s exited unexpectedly from PID %d,"
" code=%d",
ifname, ifname[0] != '\0' ? ": " : "",
name, pid, WEXITSTATUS(status));
else if (WIFSIGNALED(status))
logerrx("%s%s%s exited unexpectedly from PID %d,"
" signal=%s",
ifname, ifname[0] != '\0' ? ": " : "",
name, pid, strsignal(WTERMSIG(status)));
else
logdebugx("%s%s%s exited from PID %d",
ifname, ifname[0] != '\0' ? ": " : "",
name, pid);
if (psp != NULL)
ps_freeprocess(psp);
}
if (!(ctx->options & DHCPCD_EXITING))
return;
if (!(ps_waitforprocs(ctx)))
eloop_exit(ctx->eloop, EXIT_SUCCESS);
}
int (*handle_interface)(void *, int, const char *);
#ifdef PLUGIN_DEV
static ssize_t
ps_root_devcb(struct dhcpcd_ctx *ctx, struct ps_msghdr *psm, struct msghdr *msg)
{
int action;
struct iovec *iov = msg->msg_iov;
if (msg->msg_iovlen != 1) {
errno = EINVAL;
return -1;
}
switch(psm->ps_flags) {
case PS_DEV_IFADDED:
action = 1;
break;
case PS_DEV_IFREMOVED:
action = -1;
break;
case PS_DEV_IFUPDATED:
action = 0;
break;
default:
errno = EINVAL;
return -1;
}
return dhcpcd_handleinterface(ctx, action, iov->iov_base);
}
#endif
static ssize_t
ps_root_dispatchcb(void *arg, struct ps_msghdr *psm, struct msghdr *msg)
{
struct dhcpcd_ctx *ctx = arg;
ssize_t err;
switch(psm->ps_cmd) {
#ifdef PLUGIN_DEV
case PS_DEV_IFCMD:
err = ps_root_devcb(ctx, psm, msg);
break;
#endif
default:
#ifdef INET
err = ps_bpf_dispatch(ctx, psm, msg);
if (err == -1 && errno == ENOTSUP)
#endif
err = ps_inet_dispatch(ctx, psm, msg);
}
return err;
}
static void
ps_root_dispatch(void *arg, unsigned short events)
{
struct dhcpcd_ctx *ctx = arg;
if (ps_recvpsmsg(ctx, ctx->ps_data_fd, events,
ps_root_dispatchcb, ctx) == -1)
logerr(__func__);
}
static void
ps_root_log(void *arg, unsigned short events)
{
struct dhcpcd_ctx *ctx = arg;
if (events != ELE_READ)
logerrx("%s: unexpected event 0x%04x", __func__, events);
if (logreadfd(ctx->ps_log_root_fd) == -1)
logerr(__func__);
}
pid_t
ps_root_start(struct dhcpcd_ctx *ctx)
{
struct ps_id id = {
.psi_ifindex = 0,
.psi_cmd = PS_ROOT,
};
struct ps_process *psp;
int logfd[2] = { -1, -1}, datafd[2] = { -1, -1};
pid_t pid;
if (xsocketpair(AF_UNIX, SOCK_SEQPACKET | SOCK_CXNB, 0, logfd) == -1)
return -1;
#ifdef PRIVSEP_RIGHTS
if (ps_rights_limit_fdpair(logfd) == -1)
return -1;
#endif
if (xsocketpair(AF_UNIX, SOCK_SEQPACKET | SOCK_CXNB, 0, datafd) == -1)
return -1;
if (ps_setbuf_fdpair(datafd) == -1)
return -1;
#ifdef PRIVSEP_RIGHTS
if (ps_rights_limit_fdpair(datafd) == -1)
return -1;
#endif
psp = ctx->ps_root = ps_newprocess(ctx, &id);
if (psp == NULL)
return -1;
strlcpy(psp->psp_name, "privileged proxy", sizeof(psp->psp_name));
pid = ps_startprocess(psp, ps_root_recvmsg, NULL,
ps_root_startcb, PSF_ELOOP);
if (pid == -1)
return -1;
if (pid == 0) {
ctx->ps_log_fd = logfd[0]; /* Keep open to pass to processes */
ctx->ps_log_root_fd = logfd[1];
if (eloop_event_add(ctx->eloop, ctx->ps_log_root_fd, ELE_READ,
ps_root_log, ctx) == -1)
return -1;
ctx->ps_data_fd = datafd[1];
close(datafd[0]);
return 0;
} else if (pid == -1)
return -1;
logsetfd(logfd[0]);
close(logfd[1]);
ctx->ps_data_fd = datafd[0];
close(datafd[1]);
if (eloop_event_add(ctx->eloop, ctx->ps_data_fd, ELE_READ,
ps_root_dispatch, ctx) == -1)
return -1;
return pid;
}
void
ps_root_close(struct dhcpcd_ctx *ctx)
{
if_closesockets(ctx);
#ifdef INET
if (ctx->udp_wfd != -1) {
close(ctx->udp_wfd);
ctx->udp_wfd = -1;
}
#endif
#ifdef INET6
if (ctx->nd_fd != -1) {
close(ctx->nd_fd);
ctx->nd_fd = -1;
}
#endif
#ifdef DHCP6
if (ctx->dhcp6_wfd != -1) {
close(ctx->dhcp6_wfd);
ctx->dhcp6_wfd = -1;
}
#endif
}
int
ps_root_stop(struct dhcpcd_ctx *ctx)
{
struct ps_process *psp = ctx->ps_root;
int err;
if (!(ctx->options & DHCPCD_PRIVSEP))
return 0;
/* If we are the root process then remove the pidfile */
if (ctx->options & DHCPCD_PRIVSEPROOT) {
if (!(ctx->options & DHCPCD_TEST) && unlink(ctx->pidfile) == -1)
logerr("%s: unlink: %s", __func__, ctx->pidfile);
/* drain the log */
if (ctx->ps_log_root_fd != -1) {
ssize_t loglen;
#ifdef __linux__
/* Seems to help to get the last parts,
* sched_yield(2) does not. */
sleep(0);
#endif
do {
loglen = logreadfd(ctx->ps_log_root_fd);
} while (loglen != 0 && loglen != -1);
close(ctx->ps_log_root_fd);
ctx->ps_log_root_fd = -1;
}
}
if (ctx->ps_data_fd != -1) {
eloop_event_delete(ctx->eloop, ctx->ps_data_fd);
close(ctx->ps_data_fd);
ctx->ps_data_fd = -1;
}
/* Only the manager process gets past this point. */
if (ctx->options & DHCPCD_FORKED)
return 0;
/* We cannot log the root process exited before we
* log dhcpcd exits because the latter requires the former.
* So we just log the intent to exit.
* Even sending this will be a race to exit. */
if (psp) {
logdebugx("%s%s%s will exit from PID %d",
psp->psp_ifname,
psp->psp_ifname[0] != '\0' ? ": " : "",
psp->psp_name, psp->psp_pid);
if (ps_stopprocess(psp) == -1)
return -1;
} /* else the root process has already exited :( */