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/* Copyright (C) 2019 C. McEnroe <june@causal.agency>
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <https://www.gnu.org/licenses/>.
*/
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <netdb.h>
#include <netinet/in.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/un.h>
#include <sysexits.h>
#include <tls.h>
#include <unistd.h>
#ifdef __FreeBSD__
#include <sys/capsicum.h>
#endif
#include "bounce.h"
static struct tls *server;
static byte *readFile(size_t *len, FILE *file) {
struct stat stat;
int error = fstat(fileno(file), &stat);
if (error) err(EX_IOERR, "fstat");
byte *buf = malloc(stat.st_size);
if (!buf) err(EX_OSERR, "malloc");
*len = fread(buf, 1, stat.st_size, file);
if (ferror(file)) err(EX_IOERR, "fread");
return buf;
}
void localConfig(FILE *cert, FILE *priv) {
tls_free(server);
server = tls_server();
if (!server) errx(EX_SOFTWARE, "tls_server");
struct tls_config *config = tls_config_new();
if (!config) errx(EX_SOFTWARE, "tls_config_new");
size_t len;
byte *buf = readFile(&len, cert);
int error = tls_config_set_cert_mem(config, buf, len);
if (error) {
errx(EX_CONFIG, "tls_config_set_cert_mem: %s", tls_config_error(config));
}
free(buf);
buf = readFile(&len, priv);
error = tls_config_set_key_mem(config, buf, len);
if (error) {
errx(EX_CONFIG, "tls_config_set_key_mem: %s", tls_config_error(config));
}
free(buf);
error = tls_configure(server, config);
if (error) errx(EX_SOFTWARE, "tls_configure: %s", tls_error(server));
tls_config_free(config);
}
size_t localBind(int fds[], size_t cap, const char *host, const char *port) {
struct addrinfo *head;
struct addrinfo hints = {
.ai_family = AF_UNSPEC,
.ai_socktype = SOCK_STREAM,
.ai_protocol = IPPROTO_TCP,
};
int error = getaddrinfo(host, port, &hints, &head);
if (error) errx(EX_NOHOST, "%s:%s: %s", host, port, gai_strerror(error));
size_t len = 0;
for (struct addrinfo *ai = head; ai && len < cap; ai = ai->ai_next) {
fds[len] = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
if (fds[len] < 0) err(EX_OSERR, "socket");
int yes = 1;
error = setsockopt(fds[len], SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(yes));
if (error) err(EX_OSERR, "setsockopt");
error = bind(fds[len], ai->ai_addr, ai->ai_addrlen);
if (error) {
warn("%s:%s", host, port);
close(fds[len]);
continue;
}
len++;
}
freeaddrinfo(head);
if (!len) errx(EX_UNAVAILABLE, "could not bind any sockets");
return len;
}
static bool unix;
static int unixDir = -1;
static char unixFile[PATH_MAX];
static void unixUnlink(void) {
int error = unlinkat(unixDir, unixFile, 0);
if (error) warn("unlinkat");
}
size_t localUnix(int fds[], size_t cap, const char *path) {
if (!cap) return 0;
int sock = socket(PF_UNIX, SOCK_STREAM, 0);
if (sock < 0) err(EX_OSERR, "socket");
struct sockaddr_un addr = { .sun_family = AF_UNIX };
size_t len = strlcpy(addr.sun_path, path, sizeof(addr.sun_path));
if (len >= sizeof(addr.sun_path)) {
errx(EX_CONFIG, "path too long: %s", path);
}
int error = bind(sock, (struct sockaddr *)&addr, SUN_LEN(&addr));
if (error) err(EX_UNAVAILABLE, "%s", path);
char dir[PATH_MAX] = ".";
const char *base = strrchr(path, '/');
if (base) {
snprintf(dir, sizeof(dir), "%.*s", (int)(base - path), path);
base++;
} else {
base = path;
}
snprintf(unixFile, sizeof(unixFile), "%s", base);
unixDir = open(dir, O_DIRECTORY);
if (unixDir < 0) err(EX_UNAVAILABLE, "%s", dir);
atexit(unixUnlink);
#ifdef __FreeBSD__
cap_rights_t rights;
error = cap_rights_limit(unixDir, cap_rights_init(&rights, CAP_UNLINKAT));
if (error) err(EX_OSERR, "cap_rights_limit");
#endif
unix = true;
fds[0] = sock;
return 1;
}
static int recvfd(int sock) {
char buf[CMSG_SPACE(sizeof(int))];
char x;
struct iovec iov = { .iov_base = &x, .iov_len = 1 };
struct msghdr msg = {
.msg_iov = &iov,
.msg_iovlen = 1,
.msg_control = buf,
.msg_controllen = sizeof(buf),
};
if (0 > recvmsg(sock, &msg, 0)) return -1;
struct cmsghdr *cmsg = CMSG_FIRSTHDR(&msg);
if (!cmsg || cmsg->cmsg_type != SCM_RIGHTS) {
errno = ENOMSG;
return -1;
}
return *(int *)CMSG_DATA(cmsg);
}
struct tls *localAccept(int *fd, int bind) {
*fd = accept(bind, NULL, NULL);
if (*fd < 0) err(EX_IOERR, "accept");
if (unix) {
int sent = recvfd(*fd);
if (sent < 0) err(EX_IOERR, "recvfd");
close(*fd);
*fd = sent;
}
int yes = 1;
int error = setsockopt(*fd, SOL_SOCKET, SO_NOSIGPIPE, &yes, sizeof(yes));
if (error) err(EX_OSERR, "setsockopt");
struct tls *client;
error = tls_accept_socket(server, &client, *fd);
if (error) errx(EX_SOFTWARE, "tls_accept_socket: %s", tls_error(server));
return client;
}
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