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>
torvalds · Dec 26, 2009 · 28f6aee · 28f6aee
1 parent 4a6e47a
commit 28f6aee
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diff --git 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
@@ -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
@@ -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
@@ -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();