net: restore ip source validation

when using policy routing and the skb mark:
there are cases where a back path validation requires us
to use a different routing table for src ip validation than
the one used for mapping ingress dst ip.
One such a case is transparent proxying where we pretend to be
the destination system and therefore the local table
is used for incoming packets but possibly a main table would
be used on outbound.
Make the default behavior to allow the above and if users
need to turn on the symmetry via sysctl src_valid_mark

Signed-off-by: Jamal Hadi Salim <hadi@cyberus.ca>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/linux/inetdevice.h b/include/linux/inetdevice.h
index 699e85c..b230492 100644 (file)
--- a/include/linux/inetdevice.h
+++ b/include/linux/inetdevice.h
@@ -81,6 +81,7 @@ static inline void ipv4_devconf_setall(struct in_device *in_dev)
 #define IN_DEV_FORWARD(in_dev)         IN_DEV_CONF_GET((in_dev), FORWARDING)
 #define IN_DEV_MFORWARD(in_dev)                IN_DEV_ANDCONF((in_dev), MC_FORWARDING)
 #define IN_DEV_RPFILTER(in_dev)                IN_DEV_MAXCONF((in_dev), RP_FILTER)
+#define IN_DEV_SRC_VMARK(in_dev)       IN_DEV_ORCONF((in_dev), SRC_VMARK)
 #define IN_DEV_SOURCE_ROUTE(in_dev)    IN_DEV_ANDCONF((in_dev), \
                                                       ACCEPT_SOURCE_ROUTE)
 #define IN_DEV_ACCEPT_LOCAL(in_dev)    IN_DEV_ORCONF((in_dev), ACCEPT_LOCAL)

diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h
index 877ba03..bd27fbc 100644 (file)
--- a/include/linux/sysctl.h
+++ b/include/linux/sysctl.h
@@ -482,6 +482,7 @@ enum
        NET_IPV4_CONF_ARP_ACCEPT=21,
        NET_IPV4_CONF_ARP_NOTIFY=22,
        NET_IPV4_CONF_ACCEPT_LOCAL=23,
+       NET_IPV4_CONF_SRC_VMARK=24,
        __NET_IPV4_CONF_MAX
 };
 

diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
index 5cdbc10..040c4f0 100644 (file)
--- a/net/ipv4/devinet.c
+++ b/net/ipv4/devinet.c
@@ -1397,6 +1397,7 @@ static struct devinet_sysctl_table {
                DEVINET_SYSCTL_RW_ENTRY(ACCEPT_SOURCE_ROUTE,
                                        "accept_source_route"),
                DEVINET_SYSCTL_RW_ENTRY(ACCEPT_LOCAL, "accept_local"),
+               DEVINET_SYSCTL_RW_ENTRY(SRC_VMARK, "src_valid_mark"),
                DEVINET_SYSCTL_RW_ENTRY(PROXY_ARP, "proxy_arp"),
                DEVINET_SYSCTL_RW_ENTRY(MEDIUM_ID, "medium_id"),
                DEVINET_SYSCTL_RW_ENTRY(BOOTP_RELAY, "bootp_relay"),

diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c
index 3323168..82dbf71 100644 (file)
--- a/net/ipv4/fib_frontend.c
+++ b/net/ipv4/fib_frontend.c
@@ -252,6 +252,8 @@ int fib_validate_source(__be32 src, __be32 dst, u8 tos, int oif,
                no_addr = in_dev->ifa_list == NULL;
                rpf = IN_DEV_RPFILTER(in_dev);
                accept_local = IN_DEV_ACCEPT_LOCAL(in_dev);
+               if (mark && !IN_DEV_SRC_VMARK(in_dev))
+                       fl.mark = 0;
        }
        rcu_read_unlock();