diff options
| -rw-r--r-- | Documentation/networking/ip-sysctl.txt | 24 | ||||
| -rw-r--r-- | net/ipv4/fib_frontend.c | 2 |
2 files changed, 16 insertions, 10 deletions
diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt index ff3f219ee4d7..71041c21af9b 100644 --- a/Documentation/networking/ip-sysctl.txt +++ b/Documentation/networking/ip-sysctl.txt @@ -699,16 +699,22 @@ accept_source_route - BOOLEAN default TRUE (router) FALSE (host) -rp_filter - BOOLEAN - 1 - do source validation by reversed path, as specified in RFC1812 - Recommended option for single homed hosts and stub network - routers. Could cause troubles for complicated (not loop free) - networks running a slow unreliable protocol (sort of RIP), - or using static routes. - +rp_filter - INTEGER 0 - No source validation. - - conf/all/rp_filter must also be set to TRUE to do source validation + 1 - Strict mode as defined in RFC3704 Strict Reverse Path + Each incoming packet is tested against the FIB and if the interface + is not the best reverse path the packet check will fail. + By default failed packets are discarded. + 2 - Loose mode as defined in RFC3704 Loose Reverse Path + Each incoming packet's source address is also tested against the FIB + and if the source address is not reachable via any interface + the packet check will fail. + + Current recommended practice in RFC3704 is to enable strict mode + to prevent IP spoofin from DDos attacks. If using asymmetric routing + or other complicated routing,t hen loose mode is recommended. + + conf/all/rp_filter must also be set to non-zero to do source validation on the interface Default value is 0. Note that some distributions enable it diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c index 741e4fa3e474..cafcc49d0993 100644 --- a/net/ipv4/fib_frontend.c +++ b/net/ipv4/fib_frontend.c @@ -275,7 +275,7 @@ int fib_validate_source(__be32 src, __be32 dst, u8 tos, int oif, fib_res_put(&res); if (no_addr) goto last_resort; - if (rpf) + if (rpf == 1) goto e_inval; fl.oif = dev->ifindex; |