This fixes bug 79 and makes another clean up in the same area. Link: https://bugs.passt.top/show_bug.cgi?id=79 David Gibson (2): udp: Don't prematurely (and incorrectly) set up automatic inbound forwards udp: udp_sock_init_ns() partially duplicats udp_port_rebind_outbound() udp.c | 90 +++++++++++++++++------------------------------------------ 1 file changed, 25 insertions(+), 65 deletions(-) -- 2.43.0
For automated inbound port forwarding in pasta mode we scan bound ports
within the guest namespace via /proc and bind matching ports on the host to
listen for packets. For UDP this is usually handled by udp_timer() which
calls port_fwd_scan_udp() followed by udp_port_rebind(). However there's
one initial scan before the the UDP timer is started: we call
port_fwd_scan_udp() from port_fwd_init(), and actually bind the resulting
ports in udp_sock_init_init() called from udp_init().
Unfortunately, the version in udp_sock_init_init() isn't correct. It
unconditionally opens a new socket for every forwarded port, even if a
socket has already been explicit created with the -u option. If the
explicitly forwarded ports have particular configuration (such as a
specific bound address address, or one implied by the -o option) those will
not be replicated in the new socket. We essentially leak the original
correctly configured socket, replacing it with one which might not be
right.
We could make udp_sock_init_init() use udp_port_rebind() to get that right,
but there's actually no point doing so:
* The initial bind was introduced by ccf6d2a7b48d ("udp: Actually bind
detected namespace ports in init namespace") at which time we didn't
periodically scan for bound UDP ports. Periodic scanning was introduced
in 457ff122e ("udp,pasta: Periodically scan for ports to automatically
forward") making the bind from udp_init() redundant.
* At the time of udp_init(), programs in the guest namespace are likely
not to have started yet (unless attaching a pre-existing namespace) so
there's likely not anything to scan for anyway.
So, simply remove the initial, broken socket create/bind, allowing
automatic port forwards to be created the first time udp_timer() runs.
Reported-by: Laurent Jacquot <jk(a)lutty.net>
Suggested-by: Laurent Jacquot <jk(a)lutty.net>
Link: https://bugs.passt.top/show_bug.cgi?id=79
Signed-off-by: David Gibson <david(a)gibson.dropbear.id.au>
---
udp.c | 17 -----------------
1 file changed, 17 deletions(-)
diff --git a/udp.c b/udp.c
index b5b8f8a7..b240185e 100644
--- a/udp.c
+++ b/udp.c
@@ -1041,22 +1041,6 @@ int udp_sock_init(const struct ctx *c, int ns, sa_family_t af,
return r4 < 0 ? r4 : r6;
}
-/**
- * udp_sock_init_init() - Bind sockets in init namespace for inbound connections
- * @c: Execution context
- */
-static void udp_sock_init_init(const struct ctx *c)
-{
- unsigned dst;
-
- for (dst = 0; dst < NUM_PORTS; dst++) {
- if (!bitmap_isset(c->udp.fwd_in.f.map, dst))
- continue;
-
- udp_sock_init(c, 0, AF_UNSPEC, NULL, NULL, dst);
- }
-}
-
/**
* udp_sock_init_ns() - Bind sockets in namespace for outbound connections
* @arg: Execution context
@@ -1125,7 +1109,6 @@ int udp_init(struct ctx *c)
if (c->mode == MODE_PASTA) {
udp_splice_iov_init();
- udp_sock_init_init(c);
NS_CALL(udp_sock_init_ns, c);
}
--
2.43.0
Usually automatically forwarded UDP outbound ports are set up by
udp_port_rebind_outbound() called from udp_timer(). However, the very
first time they're created and bound is by udp_sock_init_ns() called from
udp_init(). udp_sock_init_ns() is essentially an unnecessary cut down
version of udp_port_rebind_outbound(), so we can jusat remove it.
Doing so does require moving udp_init() below udp_port_rebind_outbound()'s
definition.
Signed-off-by: David Gibson <david(a)gibson.dropbear.id.au>
---
udp.c | 73 ++++++++++++++++++++---------------------------------------
1 file changed, 25 insertions(+), 48 deletions(-)
diff --git a/udp.c b/udp.c
index b240185e..933f24b8 100644
--- a/udp.c
+++ b/udp.c
@@ -1041,29 +1041,6 @@ int udp_sock_init(const struct ctx *c, int ns, sa_family_t af,
return r4 < 0 ? r4 : r6;
}
-/**
- * udp_sock_init_ns() - Bind sockets in namespace for outbound connections
- * @arg: Execution context
- *
- * Return: 0
- */
-int udp_sock_init_ns(void *arg)
-{
- const struct ctx *c = (const struct ctx *)arg;
- unsigned dst;
-
- ns_enter(c);
-
- for (dst = 0; dst < NUM_PORTS; dst++) {
- if (!bitmap_isset(c->udp.fwd_out.f.map, dst))
- continue;
-
- udp_sock_init(c, 1, AF_UNSPEC, NULL, NULL, dst);
- }
-
- return 0;
-}
-
/**
* udp_splice_iov_init() - Set up buffers and descriptors for recvmmsg/sendmmsg
*/
@@ -1090,31 +1067,6 @@ static void udp_splice_iov_init(void)
}
}
-/**
- * udp_init() - Initialise per-socket data, and sockets in namespace
- * @c: Execution context
- *
- * Return: 0
- */
-int udp_init(struct ctx *c)
-{
- if (c->ifi4)
- udp_sock4_iov_init(c);
-
- if (c->ifi6)
- udp_sock6_iov_init(c);
-
- udp_invert_portmap(&c->udp.fwd_in);
- udp_invert_portmap(&c->udp.fwd_out);
-
- if (c->mode == MODE_PASTA) {
- udp_splice_iov_init();
- NS_CALL(udp_sock_init_ns, c);
- }
-
- return 0;
-}
-
/**
* udp_timer_one() - Handler for timed events on one port
* @c: Execution context
@@ -1272,3 +1224,28 @@ v6:
goto v6;
}
}
+
+/**
+ * udp_init() - Initialise per-socket data, and sockets in namespace
+ * @c: Execution context
+ *
+ * Return: 0
+ */
+int udp_init(struct ctx *c)
+{
+ if (c->ifi4)
+ udp_sock4_iov_init(c);
+
+ if (c->ifi6)
+ udp_sock6_iov_init(c);
+
+ udp_invert_portmap(&c->udp.fwd_in);
+ udp_invert_portmap(&c->udp.fwd_out);
+
+ if (c->mode == MODE_PASTA) {
+ udp_splice_iov_init();
+ NS_CALL(udp_port_rebind_outbound, c);
+ }
+
+ return 0;
+}
--
2.43.0
On Mon, 12 Feb 2024 17:06:56 +1100 David Gibson <david(a)gibson.dropbear.id.au> wrote:This fixes bug 79 and makes another clean up in the same area. Link: https://bugs.passt.top/show_bug.cgi?id=79 David Gibson (2): udp: Don't prematurely (and incorrectly) set up automatic inbound forwards udp: udp_sock_init_ns() partially duplicats udp_port_rebind_outbound() udp.c | 90 +++++++++++++++++------------------------------------------ 1 file changed, 25 insertions(+), 65 deletions(-)Applied. -- Stefano