[2/2] make user networking hostfwd work with restrict=y

Submitted by Jan Kiszka on June 19, 2013, 10:47 a.m.

Details

Message ID b5a87d26e848945eb891f4d7e4a7f2be514e08d5.1371638848.git.jan.kiszka@siemens.com
State New
Headers show

Commit Message

Jan Kiszka June 19, 2013, 10:47 a.m.
From: Gertjan Halkes <qemu@ghalkes.nl>

This patch allows the hostfwd option to override the restrict=y setting in
the user network stack, as explicitly stated in the documentation on the
restrict option:

     restrict=on|off
         If this option is enabled, the guest will be isolated, i.e. it
         will not be able to contact the host and no guest IP packets
         will be routed over the host to the outside. This option does
         not affect any explicitly set forwarding rules.

Qemu bug tracker:
https://bugs.launchpad.net/qemu/+bug/829455

Signed-off-by: Gertjan Halkes <qemu@ghalkes.nl>
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
---
 slirp/tcp_input.c |   26 ++++++++++++++++----------
 1 files changed, 16 insertions(+), 10 deletions(-)

Patch hide | download patch | download mbox

diff --git a/slirp/tcp_input.c b/slirp/tcp_input.c
index 6440eae..f946db8 100644
--- a/slirp/tcp_input.c
+++ b/slirp/tcp_input.c
@@ -316,16 +316,6 @@  tcp_input(struct mbuf *m, int iphlen, struct socket *inso)
 	m->m_data += sizeof(struct tcpiphdr)+off-sizeof(struct tcphdr);
 	m->m_len  -= sizeof(struct tcpiphdr)+off-sizeof(struct tcphdr);
 
-    if (slirp->restricted) {
-        for (ex_ptr = slirp->exec_list; ex_ptr; ex_ptr = ex_ptr->ex_next) {
-            if (ex_ptr->ex_fport == ti->ti_dport &&
-                ti->ti_dst.s_addr == ex_ptr->ex_addr.s_addr) {
-                break;
-            }
-        }
-        if (!ex_ptr)
-            goto drop;
-    }
 	/*
 	 * Locate pcb for segment.
 	 */
@@ -355,6 +345,22 @@  findso:
 	 * as if it was LISTENING, and continue...
 	 */
         if (so == NULL) {
+          if (slirp->restricted) {
+            /* Any hostfwds will have an existing socket, so we only get here
+             * for non-hostfwd connections. These should be dropped, unless it
+             * happens to be a guestfwd.
+             */
+            for (ex_ptr = slirp->exec_list; ex_ptr; ex_ptr = ex_ptr->ex_next) {
+                if (ex_ptr->ex_fport == ti->ti_dport &&
+                    ti->ti_dst.s_addr == ex_ptr->ex_addr.s_addr) {
+                    break;
+                }
+            }
+            if (!ex_ptr) {
+                goto dropwithreset;
+            }
+          }
+
 	  if ((tiflags & (TH_SYN|TH_FIN|TH_RST|TH_URG|TH_ACK)) != TH_SYN)
 	    goto dropwithreset;