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Don't enable SO_REUSEADDR on outgoing UDP sockets

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Currently, the outgoing UDP sockets have enabled
SO_REUSEADDR (SO_REUSEPORT on BSDs) which allows multiple UDP sockets to
bind to the same address+port.  There's one caveat though - only a
single (the last one) socket is going to receive all the incoming
traffic.  This in turn could lead to incoming DNS message matching to
invalid dns_dispatch and getting dropped.

Disable setting the SO_REUSEADDR on the outgoing UDP sockets.  This
needs to be done explicitly because `uv_udp_open()` silently enables the
option on the socket.
This commit is contained in:
Ondřej Surý
2024-09-30 18:01:47 +02:00
parent fe305f96c9
commit eec30c33c2
5 changed files with 15 additions and 11 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
lib/isc/netmgr/netmgr-int.h
View File

@@ -1321,7 +1321,7 @@ isc__nm_closesocket(uv_os_sock_t sock);
*/
isc_result_t
isc__nm_socket_reuse(uv_os_sock_t fd);
isc__nm_socket_reuse(uv_os_sock_t fd, int val);
/*%<
* Set the SO_REUSEADDR or SO_REUSEPORT (or equivalent) socket option on the fd
*/

6
lib/isc/netmgr/socket.c
View File

@@ -159,7 +159,7 @@ isc__nm_closesocket(uv_os_sock_t sock) {
}
isc_result_t
isc__nm_socket_reuse(uv_os_sock_t fd) {
isc__nm_socket_reuse(uv_os_sock_t fd, int val) {
/*
* Generally, the SO_REUSEADDR socket option allows reuse of
* local addresses.
@@ -173,12 +173,12 @@ isc__nm_socket_reuse(uv_os_sock_t fd) {
*/
#if defined(SO_REUSEPORT) && !defined(__linux__)
if (setsockopt_on(fd, SOL_SOCKET, SO_REUSEPORT) == -1) {
if (setsockopt(fd, SOL_SOCKET, SO_REUSEPORT, &val, sizeof(val)) == -1) {
return (ISC_R_FAILURE);
}
return (ISC_R_SUCCESS);
#elif defined(SO_REUSEADDR)
if (setsockopt_on(fd, SOL_SOCKET, SO_REUSEADDR) == -1) {
if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &val, sizeof(val)) == -1) {
return (ISC_R_FAILURE);
}
return (ISC_R_SUCCESS);

2
lib/isc/netmgr/tcp.c
View File

@@ -289,7 +289,7 @@ isc__nm_tcp_lb_socket(isc_nm_t *mgr, sa_family_t sa_family) {
/* FIXME: set mss */
result = isc__nm_socket_reuse(sock);
result = isc__nm_socket_reuse(sock, 1);
RUNTIME_CHECK(result == ISC_R_SUCCESS);
if (mgr->load_balance_sockets) {

14
lib/isc/netmgr/udp.c
View File

@@ -78,7 +78,7 @@ isc__nm_udp_lb_socket(isc_nm_t *mgr, sa_family_t sa_family) {
(void)isc__nm_socket_disable_pmtud(sock, sa_family);
(void)isc__nm_socket_v6only(sock, sa_family);
result = isc__nm_socket_reuse(sock);
result = isc__nm_socket_reuse(sock, 1);
RUNTIME_CHECK(result == ISC_R_SUCCESS);
if (mgr->load_balance_sockets) {
@@ -752,9 +752,10 @@ fail:
static isc_result_t
udp_connect_direct(isc_nmsocket_t *sock, isc__nm_uvreq_t *req) {
int uv_bind_flags = UV_UDP_REUSEADDR;
int uv_bind_flags = 0;
int r;
isc__networker_t *worker = sock->worker;
isc_result_t result;
r = uv_udp_init(&worker->loop->loop, &sock->uv_handle.udp);
UV_RUNTIME_CHECK(uv_udp_init, r);
@@ -771,6 +772,12 @@ udp_connect_direct(isc_nmsocket_t *sock, isc__nm_uvreq_t *req) {
}
isc__nm_incstats(sock, STATID_OPEN);
/*
* uv_udp_open() enables REUSE_ADDR, we need to disable it again.
*/
result = isc__nm_socket_reuse(sock->fd, 0);
RUNTIME_CHECK(result == ISC_R_SUCCESS);
if (sock->iface.type.sa.sa_family == AF_INET6) {
uv_bind_flags |= UV_UDP_IPV6ONLY;
}
@@ -846,9 +853,6 @@ isc_nm_udpconnect(isc_nm_t *mgr, isc_sockaddr_t *local, isc_sockaddr_t *peer,
sock->client = true;
sock->fd = fd;
result = isc__nm_socket_reuse(sock->fd);
RUNTIME_CHECK(result == ISC_R_SUCCESS ||
result == ISC_R_NOTIMPLEMENTED);
(void)isc__nm_socket_disable_pmtud(sock->fd, sa_family);

2
tests/isc/doh_test.c
View File

@@ -247,7 +247,7 @@ setup_ephemeral_port(isc_sockaddr_t *addr, sa_family_t family) {
return (r);
}
result = isc__nm_socket_reuse(fd);
result = isc__nm_socket_reuse(fd, 1);
if (result != ISC_R_SUCCESS && result != ISC_R_NOTIMPLEMENTED) {
fprintf(stderr,
"setup_ephemeral_port: isc__nm_socket_reuse(): %s",