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authorDavid Ahern <dsahern@kernel.org>2020-07-06 11:45:07 -0600
committerDavid S. Miller <davem@davemloft.net>2020-07-06 13:24:16 -0700
commit34fe5a1cf95c3f114068fc16d919c9cf4b00e428 (patch)
treee076686ebfd5e67836491ce8ffd31641fb6aeb51 /net
parenteadede5f936276e93e62834ffbe1550d305e0921 (diff)
ipv6: fib6_select_path can not use out path for nexthop objects
Brian reported a crash in IPv6 code when using rpfilter with a setup running FRR and external nexthop objects. The root cause of the crash is fib6_select_path setting fib6_nh in the result to NULL because of an improper check for nexthop objects. More specifically, rpfilter invokes ip6_route_lookup with flowi6_oif set causing fib6_select_path to be called with have_oif_match set. fib6_select_path has early check on have_oif_match and jumps to the out label which presumes a builtin fib6_nh. This path is invalid for nexthop objects; for external nexthops fib6_select_path needs to just return if the fib6_nh has already been set in the result otherwise it returns after the call to nexthop_path_fib6_result. Update the check on have_oif_match to not bail on external nexthops. Update selftests for this problem. Fixes: f88d8ea67fbd ("ipv6: Plumb support for nexthop object in a fib6_info") Reported-by: Brian Rak <brak@choopa.com> Signed-off-by: David Ahern <dsahern@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r--net/ipv6/route.c5
1 files changed, 4 insertions, 1 deletions
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 82cbb46a2a4f..ea0be7cf3d93 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -431,9 +431,12 @@ void fib6_select_path(const struct net *net, struct fib6_result *res,
struct fib6_info *sibling, *next_sibling;
struct fib6_info *match = res->f6i;
- if ((!match->fib6_nsiblings && !match->nh) || have_oif_match)
+ if (!match->nh && (!match->fib6_nsiblings || have_oif_match))
goto out;
+ if (match->nh && have_oif_match && res->nh)
+ return;
+
/* We might have already computed the hash for ICMPv6 errors. In such
* case it will always be non-zero. Otherwise now is the time to do it.
*/