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/*
* netsniff-ng - the packet sniffing beast
* Copyright 2011 Daniel Borkmann.
* Subject to the GPL, version 2.
*/
#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <string.h>
#include <syslog.h>
#include <limits.h>
#include <arpa/inet.h>
#include "die.h"
#include "locking.h"
#include "xmalloc.h"
#include "ioexact.h"
#include "ioops.h"
#include "str.h"
#include "curvetun.h"
#include "curve.h"
#include "crypto.h"
#include "curvetun_mgmt_users.h"
#include "hash.h"
struct user_store {
char username[256];
unsigned char publickey[crypto_box_pub_key_size];
struct curve25519_proto proto_inf;
struct user_store *next;
};
struct sock_map_entry {
int fd;
struct curve25519_proto *proto;
struct sock_map_entry *next;
};
struct sockaddr_map_entry {
struct sockaddr_storage *sa;
size_t sa_len;
struct curve25519_proto *proto;
struct sockaddr_map_entry *next;
};
static struct user_store *store = NULL;
static struct rwlock store_lock;
static struct hash_table sock_mapper;
static struct rwlock sock_map_lock;
static struct hash_table sockaddr_mapper;
static struct rwlock sockaddr_map_lock;
static unsigned char token[crypto_auth_hmacsha512256_KEYBYTES];
static void init_sock_mapper(void)
{
rwlock_init(&sock_map_lock);
rwlock_wr_lock(&sock_map_lock);
memset(&sock_mapper, 0, sizeof(sock_mapper));
init_hash(&sock_mapper);
rwlock_unlock(&sock_map_lock);
}
static void init_sockaddr_mapper(void)
{
rwlock_init(&sockaddr_map_lock);
rwlock_wr_lock(&sockaddr_map_lock);
memset(&sockaddr_mapper, 0, sizeof(sockaddr_mapper));
init_hash(&sockaddr_mapper);
rwlock_unlock(&sockaddr_map_lock);
}
static int cleanup_batch_sock_mapper(void *ptr)
{
struct sock_map_entry *next;
struct sock_map_entry *e = ptr;
if (!e)
return 0;
while ((next = e->next)) {
e->next = NULL;
xfree(e);
e = next;
}
xfree(e);
return 0;
}
static void destroy_sock_mapper(void)
{
rwlock_wr_lock(&sock_map_lock);
for_each_hash(&sock_mapper, cleanup_batch_sock_mapper);
free_hash(&sock_mapper);
rwlock_unlock(&sock_map_lock);
rwlock_destroy(&sock_map_lock);
}
static int cleanup_batch_sockaddr_mapper(void *ptr)
{
struct sockaddr_map_entry *next;
struct sockaddr_map_entry *e = ptr;
if (!e)
return 0;
while ((next = e->next)) {
e->next = NULL;
xfree(e);
e = next;
}
xfree(e);
return 0;
}
static void destroy_sockaddr_mapper(void)
{
rwlock_wr_lock(&sockaddr_map_lock);
for_each_hash(&sockaddr_mapper, cleanup_batch_sockaddr_mapper);
free_hash(&sockaddr_mapper);
rwlock_unlock(&sockaddr_map_lock);
rwlock_destroy(&sockaddr_map_lock);
}
static struct user_store *user_store_alloc(void)
{
return xzmalloc(sizeof(struct user_store));
}
static void user_store_free(struct user_store *us)
{
if (!us)
return;
memset(us, 0, sizeof(struct user_store));
xfree(us);
}
/* already in lock */
static int __check_duplicate_username(char *username, size_t len)
{
int duplicate = 0;
struct user_store *elem = store;
while (elem) {
if (!memcmp(elem->username, username,
strlen(elem->username) + 1)) {
duplicate = 1;
break;
}
elem = elem->next;
}
return duplicate;
}
/* already in lock */
static int __check_duplicate_pubkey(unsigned char *pubkey, size_t len)
{
int duplicate = 0;
struct user_store *elem = store;
while (elem) {
if (!memcmp(elem->publickey, pubkey,
sizeof(elem->publickey))) {
duplicate = 1;
break;
}
elem = elem->next;
}
return duplicate;
}
enum parse_states {
PARSE_USERNAME,
PARSE_PUBKEY,
PARSE_DONE,
};
static int parse_line(char *line, char *homedir)
{
char *str;
enum parse_states s = PARSE_USERNAME;
struct user_store *elem;
unsigned char pkey[crypto_box_pub_key_size];
elem = user_store_alloc();
elem->next = store;
str = strtok(line, ";");
for (; str != NULL;) {
switch (s) {
case PARSE_USERNAME:
if (__check_duplicate_username(str, strlen(str) + 1)) {
user_store_free(elem);
return -EINVAL;
}
strlcpy(elem->username, str, sizeof(elem->username));
s = PARSE_PUBKEY;
break;
case PARSE_PUBKEY:
if (!curve25519_pubkey_hexparse_32(pkey, sizeof(pkey),
str, strlen(str))) {
user_store_free(elem);
return -EINVAL;
}
if (__check_duplicate_pubkey(pkey, sizeof(pkey))) {
user_store_free(elem);
return -EINVAL;
}
memcpy(elem->publickey, pkey, sizeof(elem->publickey));
curve25519_proto_init(&elem->proto_inf, elem->publickey, sizeof(elem->publickey));
s = PARSE_DONE;
break;
case PARSE_DONE:
break;
default:
user_store_free(elem);
return -EIO;
}
str = strtok(NULL, ";");
}
store = elem;
return s == PARSE_DONE ? 0 : -EIO;
}
void parse_userfile_and_generate_user_store_or_die(char *homedir)
{
FILE *fp;
char path[PATH_MAX], buff[512];
int line = 1, ret, fd;
memset(path, 0, sizeof(path));
slprintf(path, sizeof(path), "%s/%s", homedir, FILE_CLIENTS);
rwlock_init(&store_lock);
rwlock_wr_lock(&store_lock);
fp = fopen(path, "r");
if (!fp)
panic("Cannot open client file!\n");
memset(buff, 0, sizeof(buff));
while (fgets(buff, sizeof(buff), fp) != NULL) {
buff[sizeof(buff) - 1] = 0;
/* A comment. Skip this line */
if (buff[0] == '#' || buff[0] == '\n') {
memset(buff, 0, sizeof(buff));
line++;
continue;
}
ret = parse_line(buff, homedir);
if (ret < 0)
panic("Cannot parse line %d from clients!\n", line);
line++;
memset(buff, 0, sizeof(buff));
}
fclose(fp);
if (store == NULL)
panic("No registered clients found!\n");
rwlock_unlock(&store_lock);
init_sock_mapper();
init_sockaddr_mapper();
/*
* Pubkey is also used as a hmac of the initial packet to check
* the integrity of the packet, so that we know if it's just random
* garbage or a 'valid' packet. Again, just for the integrity!
*/
memset(path, 0, sizeof(path));
slprintf(path, sizeof(path), "%s/%s", homedir, FILE_PUBKEY);
fd = open_or_die(path, O_RDONLY);
ret = read(fd, token, sizeof(token));
if (ret != crypto_auth_hmacsha512256_KEYBYTES)
panic("Cannot read public key!\n");
close(fd);
}
void dump_user_store(void)
{
int i;
struct user_store *elem;
rwlock_rd_lock(&store_lock);
elem = store;
while (elem) {
printf("%s -> ", elem->username);
for (i = 0; i < sizeof(elem->publickey); ++i)
if (i == (sizeof(elem->publickey) - 1))
printf("%02x\n", (unsigned char)
elem->publickey[i]);
else
printf("%02x:", (unsigned char)
elem->publickey[i]);
elem = elem->next;
}
rwlock_unlock(&store_lock);
}
void destroy_user_store(void)
{
struct user_store *elem, *nelem = NULL;
rwlock_wr_lock(&store_lock);
elem = store;
while (elem) {
nelem = elem->next;
elem->next = NULL;
user_store_free(elem);
elem = nelem;
}
rwlock_unlock(&store_lock);
rwlock_destroy(&store_lock);
destroy_sock_mapper();
destroy_sockaddr_mapper();
}
int username_msg(char *username, size_t len, char *dst, size_t dlen)
{
int fd;
ssize_t ret;
uint32_t salt;
unsigned char h[crypto_hash_sha512_BYTES];
struct username_struct *us = (struct username_struct *) dst;
char *uname;
size_t uname_len;
if (dlen < sizeof(struct username_struct))
return -ENOMEM;
uname_len = 512;
uname = xzmalloc(uname_len);
fd = open_or_die("/dev/random", O_RDONLY);
ret = read_exact(fd, &salt, sizeof(salt), 0);
if (ret != sizeof(salt))
panic("Cannot read from /dev/random!\n");
close(fd);
slprintf(uname, uname_len, "%s%u", username, salt);
crypto_hash_sha512(h, (unsigned char *) uname, strlen(uname));
us->salt = htonl(salt);
memcpy(us->hash, h, sizeof(us->hash));
xfree(uname);
return 0;
}
enum is_user_enum username_msg_is_user(char *src, size_t slen, char *username,
size_t len)
{
char *uname;
size_t uname_len;
uint32_t salt;
struct username_struct *us = (struct username_struct *) src;
unsigned char h[crypto_hash_sha512_BYTES];
if (slen < sizeof(struct username_struct)) {
errno = ENOMEM;
return USERNAMES_ERR;
}
uname_len = 512;
uname = xzmalloc(uname_len);
salt = ntohl(us->salt);
slprintf(uname, uname_len, "%s%u", username, salt);
crypto_hash_sha512(h, (unsigned char *) uname, strlen(uname));
xfree(uname);
if (!crypto_verify_32(&h[0], &us->hash[0]) &&
!crypto_verify_32(&h[32], &us->hash[32]))
return USERNAMES_OK;
else
return USERNAMES_NE;
}
static int register_user_by_socket(int fd, struct curve25519_proto *proto)
{
void **pos;
struct sock_map_entry *entry;
rwlock_wr_lock(&sock_map_lock);
entry = xzmalloc(sizeof(*entry));
entry->fd = fd;
entry->proto = proto;
pos = insert_hash(entry->fd, entry, &sock_mapper);
if (pos) {
entry->next = (*pos);
(*pos) = entry;
}
rwlock_unlock(&sock_map_lock);
return 0;
}
static int register_user_by_sockaddr(struct sockaddr_storage *sa,
size_t sa_len,
struct curve25519_proto *proto)
{
void **pos;
struct sockaddr_map_entry *entry;
unsigned int hash = hash_name((char *) sa, sa_len);
rwlock_wr_lock(&sockaddr_map_lock);
entry = xzmalloc(sizeof(*entry));
entry->sa = xmemdupz(sa, sa_len);
entry->sa_len = sa_len;
entry->proto = proto;
pos = insert_hash(hash, entry, &sockaddr_mapper);
if (pos) {
entry->next = (*pos);
(*pos) = entry;
}
rwlock_unlock(&sockaddr_map_lock);
return 0;
}
int try_register_user_by_socket(struct curve25519_struct *c,
char *src, size_t slen, int sock, int log)
{
int ret = -1;
char *cbuff = NULL;
size_t real_len = 132;
ssize_t clen;
struct user_store *elem;
enum is_user_enum err;
unsigned char auth[crypto_auth_hmacsha512256_BYTES];
struct taia arrival_taia;
/* assert(132 == clen + sizeof(auth)); */
/*
* Check hmac first, if malicious, drop immediately before we
* investigate more efforts.
*/
if (slen < real_len)
return -1;
taia_now(&arrival_taia);
memcpy(auth, src, sizeof(auth));
src += sizeof(auth);
real_len -= sizeof(auth);
if (crypto_auth_hmacsha512256_verify(auth, (unsigned char *) src,
real_len, token)) {
syslog(LOG_ERR, "Bad packet hmac for id %d! Dropping!\n", sock);
return -1;
} else {
if (log)
syslog(LOG_INFO, "Good packet hmac for id %d!\n", sock);
}
rwlock_rd_lock(&store_lock);
elem = store;
while (elem) {
clen = curve25519_decode(c, &elem->proto_inf,
(unsigned char *) src, real_len,
(unsigned char **) &cbuff,
&arrival_taia);
if (clen <= 0) {
elem = elem->next;
continue;
}
cbuff += crypto_box_zerobytes;
clen -= crypto_box_zerobytes;
if (log)
syslog(LOG_INFO, "Packet decoded successfully for id %d!\n", sock);
err = username_msg_is_user(cbuff, clen, elem->username,
strlen(elem->username) + 1);
if (err == USERNAMES_OK) {
if (log)
syslog(LOG_INFO, "Found user %s for id %d! Registering ...\n",
elem->username, sock);
ret = register_user_by_socket(sock, &elem->proto_inf);
break;
}
elem = elem->next;
}
rwlock_unlock(&store_lock);
if (ret == -1)
syslog(LOG_ERR, "User not found! Dropping connection!\n");
return ret;
}
int try_register_user_by_sockaddr(struct curve25519_struct *c,
char *src, size_t slen,
struct sockaddr_storage *sa,
size_t sa_len, int log)
{
int ret = -1;
char *cbuff = NULL;
struct user_store *elem;
ssize_t clen;
size_t real_len = 132;
enum is_user_enum err;
unsigned char auth[crypto_auth_hmacsha512256_BYTES];
struct taia arrival_taia;
/* assert(132 == clen + sizeof(auth)); */
/*
* Check hmac first, if malicious, drop immediately before we
* investigate more efforts.
*/
if (slen < real_len)
return -1;
taia_now(&arrival_taia);
memcpy(auth, src, sizeof(auth));
src += sizeof(auth);
real_len -= sizeof(auth);
if (crypto_auth_hmacsha512256_verify(auth, (unsigned char *) src,
real_len, token)) {
syslog(LOG_ERR, "Got bad packet hmac! Dropping!\n");
return -1;
} else {
if (log)
syslog(LOG_INFO, "Got good packet hmac!\n");
}
rwlock_rd_lock(&store_lock);
elem = store;
while (elem) {
clen = curve25519_decode(c, &elem->proto_inf,
(unsigned char *) src, real_len,
(unsigned char **) &cbuff,
&arrival_taia);
if (clen <= 0) {
elem = elem->next;
continue;
}
cbuff += crypto_box_zerobytes;
clen -= crypto_box_zerobytes;
if (log)
syslog(LOG_INFO, "Packet decoded successfully!\n");
err = username_msg_is_user(cbuff, clen, elem->username,
strlen(elem->username) + 1);
if (err == USERNAMES_OK) {
if (log)
syslog(LOG_INFO, "Found user %s! Registering ...\n",
elem->username);
ret = register_user_by_sockaddr(sa, sa_len,
&elem->proto_inf);
break;
}
elem = elem->next;
}
rwlock_unlock(&store_lock);
if (ret == -1)
syslog(LOG_ERR, "User not found! Dropping connection!\n");
return ret;
}
int get_user_by_socket(int fd, struct curve25519_proto **proto)
{
int ret = -1;
struct sock_map_entry *entry;
errno = 0;
rwlock_rd_lock(&sock_map_lock);
entry = lookup_hash(fd, &sock_mapper);
while (entry && fd != entry->fd)
entry = entry->next;
if (entry && fd == entry->fd) {
(*proto) = entry->proto;
ret = 0;
} else {
(*proto) = NULL;
errno = ENOENT;
}
rwlock_unlock(&sock_map_lock);
return ret;
}
int get_user_by_sockaddr(struct sockaddr_storage *sa, size_t sa_len,
struct curve25519_proto **proto)
{
int ret = -1;
struct sockaddr_map_entry *entry;
unsigned int hash = hash_name((char *) sa, sa_len);
errno = 0;
rwlock_rd_lock(&sockaddr_map_lock);
entry = lookup_hash(hash, &sockaddr_mapper);
while (entry && entry->sa_len == sa_len &&
memcmp(sa, entry->sa, entry->sa_len))
entry = entry->next;
if (entry && entry->sa_len == sa_len &&
!memcmp(sa, entry->sa, entry->sa_len)) {
(*proto) = entry->proto;
ret = 0;
} else {
(*proto) = NULL;
errno = ENOENT;
}
rwlock_unlock(&sockaddr_map_lock);
return ret;
}
static struct sock_map_entry *socket_to_sock_map_entry(int fd)
{
struct sock_map_entry *entry, *ret = NULL;
errno = 0;
rwlock_rd_lock(&sock_map_lock);
entry = lookup_hash(fd, &sock_mapper);
while (entry && fd != entry->fd)
entry = entry->next;
if (entry && fd == entry->fd)
ret = entry;
else
errno = ENOENT;
rwlock_unlock(&sock_map_lock);
return ret;
}
void remove_user_by_socket(int fd)
{
struct sock_map_entry *pos;
struct sock_map_entry *entry = socket_to_sock_map_entry(fd);
if (!entry)
return;
rwlock_wr_lock(&sock_map_lock);
pos = remove_hash(entry->fd, entry, entry->next, &sock_mapper);
while (pos && pos->next && pos->next != entry)
pos = pos->next;
if (pos && pos->next && pos->next == entry)
pos->next = entry->next;
memset(entry->proto->enonce, 0, sizeof(entry->proto->enonce));
memset(entry->proto->dnonce, 0, sizeof(entry->proto->dnonce));
entry->proto = NULL;
entry->next = NULL;
xfree(entry);
rwlock_unlock(&sock_map_lock);
}
static struct sockaddr_map_entry *
sockaddr_to_sockaddr_map_entry(struct sockaddr_storage *sa, size_t sa_len)
{
struct sockaddr_map_entry *entry, *ret = NULL;
unsigned int hash = hash_name((char *) sa, sa_len);
errno = 0;
rwlock_rd_lock(&sockaddr_map_lock);
entry = lookup_hash(hash, &sockaddr_mapper);
while (entry && entry->sa_len == sa_len &&
memcmp(sa, entry->sa, entry->sa_len))
entry = entry->next;
if (entry && entry->sa_len == sa_len &&
!memcmp(sa, entry->sa, entry->sa_len))
ret = entry;
else
errno = ENOENT;
rwlock_unlock(&sockaddr_map_lock);
return ret;
}
void remove_user_by_sockaddr(struct sockaddr_storage *sa, size_t sa_len)
{
struct sockaddr_map_entry *pos;
struct sockaddr_map_entry *entry;
unsigned int hash = hash_name((char *) sa, sa_len);
entry = sockaddr_to_sockaddr_map_entry(sa, sa_len);
if (!entry)
return;
rwlock_wr_lock(&sockaddr_map_lock);
pos = remove_hash(hash, entry, entry->next, &sockaddr_mapper);
while (pos && pos->next && pos->next != entry)
pos = pos->next;
if (pos && pos->next && pos->next == entry)
pos->next = entry->next;
memset(entry->proto->enonce, 0, sizeof(entry->proto->enonce));
memset(entry->proto->dnonce, 0, sizeof(entry->proto->dnonce));
entry->proto = NULL;
entry->next = NULL;
xfree(entry->sa);
xfree(entry);
rwlock_unlock(&sockaddr_map_lock);
}
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