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-rw-r--r--src/dnsproxy.c106
1 files changed, 73 insertions, 33 deletions
diff --git a/src/dnsproxy.c b/src/dnsproxy.c
index 37ba2ac4..09c2bd46 100644
--- a/src/dnsproxy.c
+++ b/src/dnsproxy.c
@@ -1703,10 +1703,9 @@ static int ns_resolv(struct server_data *server, struct request_data *req,
for (GList *list = server->domains; list; list = list->next) {
int domlen, altlen;
unsigned char alt[1024];
- /* TODO: is this a bug? the offset isn't considered here... */
- struct domain_hdr *hdr = (void *) &alt;
const char *domain = list->data;
const size_t offset = protocol_offset(server->protocol);
+ struct domain_hdr *hdr = (void *) (&alt[0] + offset);
if (!domain)
continue;
@@ -1718,10 +1717,10 @@ static int ns_resolv(struct server_data *server, struct request_data *req,
memcpy(alt + offset, &req->altid, sizeof(req->altid));
- memcpy(alt + offset + 2, request + offset + 2, 10);
+ memcpy(alt + offset + 2, request + offset + 2, DNS_HEADER_SIZE - 2);
hdr->qdcount = htons(1);
- altlen = append_query(alt + offset + DNS_HEADER_SIZE, sizeof(alt) - DNS_HEADER_SIZE,
+ altlen = append_query(alt + offset + DNS_HEADER_SIZE, sizeof(alt) - DNS_HEADER_SIZE - offset,
name, domain);
if (altlen < 0)
return -EINVAL;
@@ -2147,31 +2146,41 @@ static int dns_reply_fixup_domains(
return reply_len;
}
-static int forward_dns_reply(char *reply, size_t reply_len, int protocol,
- struct server_data *data)
+static struct request_data* lookup_request(
+ const unsigned char *reply, size_t len, int protocol)
{
const size_t offset = protocol_offset(protocol);
struct request_data *req;
struct domain_hdr *hdr = (void *)(reply + offset);
- int err, sk;
- debug("Received %zd bytes (id 0x%04x)", reply_len, hdr->id);
+ debug("Received %zd bytes (id 0x%04x)", len, hdr->id);
- if (reply_len < sizeof(struct domain_hdr) + offset)
- return -EINVAL;
+ if (len < sizeof(struct domain_hdr) + offset)
+ return NULL;
req = find_request(hdr->id);
+
if (!req)
- return -EINVAL;
+ return NULL;
debug("req %p dstid 0x%04x altid 0x%04x rcode %d",
req, req->dstid, req->altid, hdr->rcode);
+ req->numresp++;
+
+ return req;
+}
+
+static int forward_dns_reply(char *reply, size_t reply_len, int protocol,
+ struct server_data *data, struct request_data *req)
+{
+ const size_t offset = protocol_offset(protocol);
+ struct domain_hdr *hdr = (void *)(reply + offset);
+ int err, sk;
+
/* replace with original request ID from our client */
hdr->id = req->srcid;
- req->numresp++;
-
if (hdr->rcode == ns_r_noerror || !req->resp) {
/*
* If the domain name was appended remove it before forwarding
@@ -2248,8 +2257,6 @@ static int forward_dns_reply(char *reply, size_t reply_len, int protocol,
else
debug("proto %d sent %d bytes to %d", protocol, err, sk);
- destroy_request_data(req);
-
return err;
}
@@ -2313,9 +2320,10 @@ static gboolean udp_server_event(GIOChannel *channel, GIOCondition condition,
gpointer user_data)
{
unsigned char buf[4096];
- int sk;
+ int sk, res;
ssize_t len;
struct server_data *data = user_data;
+ struct request_data *req;
if (condition & (G_IO_NVAL | G_IO_ERR | G_IO_HUP)) {
connman_error("Error with UDP server %s", data->server);
@@ -2326,9 +2334,20 @@ static gboolean udp_server_event(GIOChannel *channel, GIOCondition condition,
sk = g_io_channel_unix_get_fd(channel);
len = recv(sk, buf, sizeof(buf), 0);
- if (len > 0) {
- forward_dns_reply((char*)buf, len, IPPROTO_UDP, data);
- }
+ if (len <= 0)
+ return TRUE;
+
+ req = lookup_request(buf, len, IPPROTO_UDP);
+
+ if (!req)
+ /* invalid / corrupt request */
+ return TRUE;
+
+ res = forward_dns_reply((char*)buf, len, IPPROTO_UDP, data, req);
+
+ /* on success or no further responses are expected, destroy the req */
+ if (res == 0 || req->numresp >= req->numserv)
+ destroy_request_data(req);
return TRUE;
}
@@ -2336,6 +2355,7 @@ static gboolean udp_server_event(GIOChannel *channel, GIOCondition condition,
static gboolean tcp_server_event(GIOChannel *channel, GIOCondition condition,
gpointer user_data)
{
+ struct request_data *req;
struct server_data *server = user_data;
int sk = g_io_channel_unix_get_fd(channel);
if (sk == 0)
@@ -2355,8 +2375,8 @@ hangup:
list = request_list;
while (list) {
- struct request_data *req = list->data;
struct domain_hdr *hdr;
+ req = list->data;
list = list->next;
if (req->protocol == IPPROTO_UDP)
@@ -2422,7 +2442,7 @@ hangup:
* need to delete elements while iterating through it */
for (GSList *list = request_list; list; ) {
int status;
- struct request_data *req = list->data;
+ req = list->data;
if (req->protocol == IPPROTO_UDP) {
list = list->next;
@@ -2465,6 +2485,7 @@ hangup:
} else if (condition & G_IO_IN) {
struct partial_reply *reply = server->incoming_reply;
int bytes_recv;
+ int res;
if (!reply) {
uint16_t reply_len;
@@ -2479,7 +2500,7 @@ hangup:
connman_error("DNS proxy error %s",
strerror(errno));
goto hangup;
- } else if (bytes_recv < 2)
+ } else if (bytes_recv < sizeof(reply_len))
return TRUE;
/* the header contains the length of the message
@@ -2493,6 +2514,8 @@ hangup:
return TRUE;
reply->len = reply_len;
+ /* we only peeked the two length bytes, so we have to
+ receive the complete message below proper. */
reply->received = 0;
server->incoming_reply = reply;
@@ -2515,15 +2538,30 @@ hangup:
reply->received += bytes_recv;
}
- forward_dns_reply((char*)reply->buf, reply->received, IPPROTO_TCP,
- server);
+ req = lookup_request(reply->buf, reply->received, IPPROTO_TCP);
+
+ if (!req)
+ /* invalid / corrupt request */
+ return TRUE;
+
+ res = forward_dns_reply((char*)reply->buf, reply->received, IPPROTO_TCP, server, req);
g_free(reply);
server->incoming_reply = NULL;
- destroy_server(server);
+ /* on success or if no further responses are expected close
+ * connection */
+ if (res == 0 || req->numresp >= req->numserv) {
+ destroy_request_data(req);
+ destroy_server(server);
+ return FALSE;
+ }
- return FALSE;
+ /*
+ * keep the TCP connection open, there are more
+ * requests to be answered
+ */
+ return TRUE;
}
return TRUE;
@@ -3183,7 +3221,7 @@ static bool read_tcp_data(struct tcp_partial_client_data *client,
client->buf_end += read_len;
/* we need at least the message length header */
- if (client->buf_end < 2)
+ if (client->buf_end < DNS_HEADER_TCP_EXTRA_BYTES)
return true;
msg_len = get_msg_len(client->buf);
@@ -3207,9 +3245,11 @@ read_another:
debug("client %d all data %zd received", client_sk, msg_len);
- err = parse_request(client->buf + 2, msg_len, query, sizeof(query));
+ err = parse_request(client->buf + DNS_HEADER_TCP_EXTRA_BYTES,
+ msg_len, query, sizeof(query));
if (err < 0 || (g_slist_length(server_list) == 0)) {
- send_response(client_sk, client->buf, msg_len + 2,
+ send_response(client_sk, client->buf,
+ msg_len + DNS_HEADER_TCP_EXTRA_BYTES,
NULL, 0, IPPROTO_TCP);
return true;
}
@@ -3224,12 +3264,12 @@ read_another:
req->protocol = IPPROTO_TCP;
req->family = client->family;
- hdr = (void*)(client->buf + 2);
+ hdr = (void*)(client->buf + DNS_HEADER_TCP_EXTRA_BYTES);
memcpy(&req->srcid, &hdr->id, sizeof(req->srcid));
req->dstid = get_id();
req->altid = get_id();
- req->request_len = msg_len + 2;
+ req->request_len = msg_len + DNS_HEADER_TCP_EXTRA_BYTES;
/* replace ID the request for forwarding */
memcpy(&hdr->id, &req->dstid, sizeof(hdr->id));
@@ -3313,7 +3353,7 @@ read_another:
request_list = g_slist_append(request_list, req);
out:
- if (client->buf_end > (msg_len + 2)) {
+ if (client->buf_end > (msg_len + DNS_HEADER_TCP_EXTRA_BYTES)) {
debug("client %d buf %p -> %p end %d len %d new %zd",
client_sk,
client->buf + msg_len + 2,
@@ -3537,7 +3577,7 @@ static bool tcp_listener_event(GIOChannel *channel, GIOCondition condition,
return true;
}
- if (recv_len < 2) {
+ if (recv_len < DNS_HEADER_TCP_EXTRA_BYTES) {
debug("client %d not enough data to read, waiting", client_sk);
client->buf_end += recv_len;
return true;
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