1 files changed, 760 insertions, 0 deletions

diff --git a/curvetun_mgmt_users.c b/curvetun_mgmt_users.c
new file mode 100644
index 0000000..665ceb3
--- /dev/null
+++ b/curvetun_mgmt_users.c
@@ -0,0 +1,760 @@
+/*
+ * 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))
+				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)))
+				return -EINVAL;
+			if (__check_duplicate_pubkey(pkey, sizeof(pkey)))
+				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:
+			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);
+}