[Qemu-devel] [PATCH 02/10] slirp: Canonicalize restrict syntax

[Jan Kiszka]

All other boolean arguments accept on|off - except for slirp's restrict.
Fix that while still accepting the formerly allowed yes|y|no|n, but
reject everything else. This avoids accidentally allowing external
connections because syntax errors were so far interpreted as
'restrict=no'.

CC: Gleb Natapov <address@hidden>
Signed-off-by: Jan Kiszka <address@hidden>
---
 net/slirp.c     |   21 +++++++++++++++------
 qemu-options.hx |    4 ++--
 2 files changed, 17 insertions(+), 8 deletions(-)

diff --git a/net/slirp.c b/net/slirp.c
index e057a14..71e2577 100644
--- a/net/slirp.c
+++ b/net/slirp.c
@@ -240,7 +240,8 @@ static int net_slirp_init(VLANState *vlan, const char 
*model,
     nc = qemu_new_net_client(&net_slirp_info, vlan, NULL, model, name);
 
     snprintf(nc->info_str, sizeof(nc->info_str),
-             "net=%s, restricted=%c", inet_ntoa(net), restricted ? 'y' : 'n');
+             "net=%s,restrict=%s", inet_ntoa(net),
+             restricted ? "on" : "off");
 
     s = DO_UPCAST(SlirpState, nc, nc);
 
@@ -689,6 +690,7 @@ int net_init_slirp(QemuOpts *opts,
     const char *bootfile;
     const char *smb_export;
     const char *vsmbsrv;
+    const char *restrict_opt;
     char *vnet = NULL;
     int restricted = 0;
     int ret;
@@ -702,6 +704,18 @@ int net_init_slirp(QemuOpts *opts,
     smb_export  = qemu_opt_get(opts, "smb");
     vsmbsrv     = qemu_opt_get(opts, "smbserver");
 
+    restrict_opt = qemu_opt_get(opts, "restrict");
+    if (restrict_opt) {
+        if (!strcmp(restrict_opt, "on") ||
+            !strcmp(restrict_opt, "yes") || !strcmp(restrict_opt, "y")) {
+            restricted = 1;
+        } else if (strcmp(restrict_opt, "off") &&
+            strcmp(restrict_opt, "no") && strcmp(restrict_opt, "n")) {
+            error_report("invalid option: 'restrict=%s'", restrict_opt);
+            return -1;
+        }
+    }
+
     if (qemu_opt_get(opts, "ip")) {
         const char *ip = qemu_opt_get(opts, "ip");
         int l = strlen(ip) + strlen("/24") + 1;
@@ -720,11 +734,6 @@ int net_init_slirp(QemuOpts *opts,
         vnet = qemu_strdup(qemu_opt_get(opts, "net"));
     }
 
-    if (qemu_opt_get(opts, "restrict") &&
-        qemu_opt_get(opts, "restrict")[0] == 'y') {
-        restricted = 1;
-    }
-
     qemu_opt_foreach(opts, net_init_slirp_configs, NULL, 0);
 
     ret = net_slirp_init(vlan, "user", name, restricted, vnet, vhost,
diff --git a/qemu-options.hx b/qemu-options.hx
index e6d7adc..0f58e27 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -1092,7 +1092,7 @@ DEF("net", HAS_ARG, QEMU_OPTION_net,
     "-net 
nic[,vlan=n][,macaddr=mac][,model=type][,name=str][,addr=str][,vectors=v]\n"
     "                create a new Network Interface Card and connect it to 
VLAN 'n'\n"
 #ifdef CONFIG_SLIRP
-    "-net 
user[,vlan=n][,name=str][,net=addr[/mask]][,host=addr][,restrict=y|n]\n"
+    "-net 
user[,vlan=n][,name=str][,net=addr[/mask]][,host=addr][,restrict=on|off]\n"
     "         
[,hostname=host][,dhcpstart=addr][,dns=addr][,tftp=dir][,bootfile=f]\n"
     "         [,hostfwd=rule][,guestfwd=rule]"
 #ifndef _WIN32
@@ -1185,7 +1185,7 @@ either in the form a.b.c.d or as number of valid top-most 
bits. Default is
 Specify the guest-visible address of the host. Default is the 2nd IP in the
 guest network, i.e. x.x.x.2.
 
address@hidden restrict=y|yes|n|no
address@hidden 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.
-- 
1.7.3.4