On 2/14/18 10:28 AM, Stefano Brivio wrote: > In fib_nh_match(), if output interface or gateway are passed in > the FIB configuration, we don't have to check next hops of > multipath routes to conclude whether we have a match or not. > > However, we might still have routes with different realms > matching the same output interface and gateway configuration, > and this needs to cause the match to fail. Otherwise the first > route inserted in the FIB will match, regardless of the realms: > > # ip route add 1.1.1.1 dev eth0 table 1234 realms 1/2 > # ip route append 1.1.1.1 dev eth0 table 1234 realms 3/4 > # ip route list table 1234 > 1.1.1.1 dev eth0 scope link realms 1/2 > 1.1.1.1 dev eth0 scope link realms 3/4 > # ip route del 1.1.1.1 dev ens3 table 1234 realms 3/4 > # ip route list table 1234 > 1.1.1.1 dev ens3 scope link realms 3/4 > > whereas route with realms 3/4 should have been deleted instead. > > Explicitly check for fc_flow passed in the FIB configuration > (this comes from RTA_FLOW extracted by rtm_to_fib_config()) and > fail matching if it differs from nh_tclassid. > > The handling of RTA_FLOW for multipath routes later in > fib_nh_match() is still needed, as we can have multiple RTA_FLOW > attributes that need to be matched against the tclassid of each > next hop. > > Reported-by: Jianlin Shi <ji...@redhat.com> > Signed-off-by: Stefano Brivio <sbri...@redhat.com> > --- > net/ipv4/fib_semantics.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/net/ipv4/fib_semantics.c b/net/ipv4/fib_semantics.c > index c586597da20d..2223ebac5b64 100644 > --- a/net/ipv4/fib_semantics.c > +++ b/net/ipv4/fib_semantics.c > @@ -646,6 +646,10 @@ int fib_nh_match(struct fib_config *cfg, struct fib_info > *fi, > fi->fib_nh, cfg, extack)) > return 1; > } > +#ifdef CONFIG_IP_ROUTE_CLASSID > + if (cfg->fc_flow != fi->fib_nh->nh_tclassid) > + return 1; > +#endif
you should verify fc_flow is set. user is allowed to delete first matching route based on data that is given. > if ((!cfg->fc_oif || cfg->fc_oif == fi->fib_nh->nh_oif) && > (!cfg->fc_gw || cfg->fc_gw == fi->fib_nh->nh_gw)) > return 0; >
