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Netlink: Improve multipath parsing errors

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Function nl_parse_multipath() should handle errors internally.
This commit is contained in:
Ondrej Zajicek (work) 2022-01-05 18:46:41 +01:00
parent 29dda184e5
commit 77d032c71f
1 changed files with 25 additions and 16 deletions
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41
sysdep/linux/netlink.c
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@ -681,7 +681,7 @@ nl_add_multipath(struct nlmsghdr *h, uint bufsize, struct nexthop *nh, int af, e
} }
static struct nexthop * static struct nexthop *
nl_parse_multipath(struct nl_parse_state *s, struct krt_proto *p, struct rtattr *ra, int af) nl_parse_multipath(struct nl_parse_state *s, struct krt_proto *p, const net_addr *n, struct rtattr *ra, int af)
{ {
struct rtattr *a[BIRD_RTA_MAX]; struct rtattr *a[BIRD_RTA_MAX];
struct rtnexthop *nh = RTA_DATA(ra); struct rtnexthop *nh = RTA_DATA(ra);
@ -695,7 +695,7 @@ nl_parse_multipath(struct nl_parse_state *s, struct krt_proto *p, struct rtattr
{ {
/* Use RTNH_OK(nh,len) ?? */ /* Use RTNH_OK(nh,len) ?? */
if ((len < sizeof(*nh)) || (len < nh->rtnh_len)) if ((len < sizeof(*nh)) || (len < nh->rtnh_len))
return NULL; goto err;
if (nh->rtnh_flags & RTNH_F_DEAD) if (nh->rtnh_flags & RTNH_F_DEAD)
goto next; goto next;
@ -706,7 +706,10 @@ nl_parse_multipath(struct nl_parse_state *s, struct krt_proto *p, struct rtattr
rv->weight = nh->rtnh_hops; rv->weight = nh->rtnh_hops;
rv->iface = if_find_by_index(nh->rtnh_ifindex); rv->iface = if_find_by_index(nh->rtnh_ifindex);
if (!rv->iface) if (!rv->iface)
return NULL; {
log(L_ERR "KRT: Received route %N with unknown ifindex %u", n, nh->rtnh_ifindex);
return NULL;
}
/* Nonexistent RTNH_PAYLOAD ?? */ /* Nonexistent RTNH_PAYLOAD ?? */
nl_attr_len = nh->rtnh_len - RTNH_LENGTH(0); nl_attr_len = nh->rtnh_len - RTNH_LENGTH(0);
@ -714,18 +717,18 @@ nl_parse_multipath(struct nl_parse_state *s, struct krt_proto *p, struct rtattr
{ {
case AF_INET: case AF_INET:
if (!nl_parse_attrs(RTNH_DATA(nh), nexthop_attr_want4, a, sizeof(a))) if (!nl_parse_attrs(RTNH_DATA(nh), nexthop_attr_want4, a, sizeof(a)))
return NULL; goto err;
break; break;
case AF_INET6: case AF_INET6:
if (!nl_parse_attrs(RTNH_DATA(nh), nexthop_attr_want6, a, sizeof(a))) if (!nl_parse_attrs(RTNH_DATA(nh), nexthop_attr_want6, a, sizeof(a)))
return NULL; goto err;
break; break;
#ifdef HAVE_MPLS_KERNEL #ifdef HAVE_MPLS_KERNEL
case AF_MPLS: case AF_MPLS:
if (!nl_parse_attrs(RTNH_DATA(nh), nexthop_attr_want_mpls, a, sizeof(a))) if (!nl_parse_attrs(RTNH_DATA(nh), nexthop_attr_want_mpls, a, sizeof(a)))
return NULL; goto err;
if (a[RTA_NEWDST]) if (a[RTA_NEWDST])
rv->labels = rta_get_mpls(a[RTA_NEWDST], rv->label); rv->labels = rta_get_mpls(a[RTA_NEWDST], rv->label);
@ -734,7 +737,7 @@ nl_parse_multipath(struct nl_parse_state *s, struct krt_proto *p, struct rtattr
#endif #endif
default: default:
return NULL; goto err;
} }
if (a[RTA_GATEWAY]) if (a[RTA_GATEWAY])
@ -757,14 +760,19 @@ nl_parse_multipath(struct nl_parse_state *s, struct krt_proto *p, struct rtattr
nbr = neigh_find(&p->p, rv->gw, rv->iface, nbr = neigh_find(&p->p, rv->gw, rv->iface,
(rv->flags & RNF_ONLINK) ? NEF_ONLINK : 0); (rv->flags & RNF_ONLINK) ? NEF_ONLINK : 0);
if (!nbr || (nbr->scope == SCOPE_HOST)) if (!nbr || (nbr->scope == SCOPE_HOST))
return NULL; {
log(L_ERR "KRT: Received route %N with strange next-hop %I", n, rv->gw);
return NULL;
}
} }
#ifdef HAVE_MPLS_KERNEL #ifdef HAVE_MPLS_KERNEL
if (a[RTA_ENCAP] && a[RTA_ENCAP_TYPE]) if (a[RTA_ENCAP] && a[RTA_ENCAP_TYPE])
{ {
if (rta_get_u16(a[RTA_ENCAP_TYPE]) != LWTUNNEL_ENCAP_MPLS) { if (rta_get_u16(a[RTA_ENCAP_TYPE]) != LWTUNNEL_ENCAP_MPLS)
log(L_WARN "KRT: Unknown encapsulation method %d in multipath", rta_get_u16(a[RTA_ENCAP_TYPE])); {
log(L_WARN "KRT: Received route %N with unknown encapsulation method %d",
n, rta_get_u16(a[RTA_ENCAP_TYPE]));
return NULL; return NULL;
} }
@ -785,6 +793,10 @@ nl_parse_multipath(struct nl_parse_state *s, struct krt_proto *p, struct rtattr
first = nexthop_sort(first); first = nexthop_sort(first);
return first; return first;
err:
log(L_ERR "KRT: Received strange multipath route %N", n);
return NULL;
} }
static void static void
@ -1675,19 +1687,16 @@ nl_parse_route(struct nl_parse_state *s, struct nlmsghdr *h)
if (a[RTA_MULTIPATH]) if (a[RTA_MULTIPATH])
{ {
struct nexthop *nh = nl_parse_multipath(s, p, a[RTA_MULTIPATH], i->rtm_family); struct nexthop *nh = nl_parse_multipath(s, p, n, a[RTA_MULTIPATH], i->rtm_family);
if (!nh) if (!nh)
{ SKIP("strange RTA_MULTIPATH\n");
log(L_ERR "KRT: Received strange multipath route %N", net->n.addr);
return;
}
nexthop_link(ra, nh); nexthop_link(ra, nh);
break; break;
} }
if (i->rtm_flags & RTNH_F_DEAD) if (i->rtm_flags & RTNH_F_DEAD)
return; SKIP("ignore RTNH_F_DEAD\n");
ra->nh.iface = if_find_by_index(oif); ra->nh.iface = if_find_by_index(oif);
if (!ra->nh.iface) if (!ra->nh.iface)