From: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Date: Thu, 5 Aug 2010 13:46:53 -0700
>> I think the problem is net/ipv4/fib_frontend.c fib_validate_source()
>>
>> ...
>> #ifdef CONFIG_IP_ROUTE_MULTIPATH
>> if (FIB_RES_DEV(res) == dev || res.fi->fib_nhs > 1)
>> #else
>> if (FIB_RES_DEV(res) == dev)
>> #endif
>> ...
>>
>> I'm not sure, but this code is quite trivial and self-speaking. In case we have
>> several default routes, we'd better iterate over each of them and compare
>> resulting devices with the input one. So, fix is also trivial, specially for
>> network kernel developers. ;-)
Please test this patch:
ipv4: Fix reverse path filtering with multipath routing.
Actually iterate over the next-hops to make sure we have
a device match. Otherwise RP filtering is always elided
when the route matched has multiple next-hops.
Reported-by: Igor M Podlesny <for.poige@xxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c
index a439689..7d02a9f 100644
--- a/net/ipv4/fib_frontend.c
+++ b/net/ipv4/fib_frontend.c
@@ -246,6 +246,7 @@ int fib_validate_source(__be32 src, __be32 dst, u8 tos, int oif,
struct fib_result res;
int no_addr, rpf, accept_local;
+ bool dev_match;
int ret;
struct net *net;
@@ -273,12 +274,22 @@ int fib_validate_source(__be32 src, __be32 dst, u8 tos, int oif,
}
*spec_dst = FIB_RES_PREFSRC(res);
fib_combine_itag(itag, &res);
+ dev_match = false;
+
#ifdef CONFIG_IP_ROUTE_MULTIPATH
- if (FIB_RES_DEV(res) == dev || res.fi->fib_nhs > 1)
+ for (ret = 0; ret < res.fi->fib_nhs; ret++) {
+ struct fib_nh *nh = &res.fi->fib_nh[ret];
+
+ if (nh->nh_dev == dev) {
+ dev_match = true;
+ break;
+ }
+ }
#else
if (FIB_RES_DEV(res) == dev)
+ dev_match = true;
#endif
- {
+ if (dev_match) {
ret = FIB_RES_NH(res).nh_scope >= RT_SCOPE_HOST;
fib_res_put(&res);
return ret;
--
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