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In rde_attr_missing() make sure the nexthop attribute is present if there

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is any nlri data. In rde_as4byte_fixup() only run if ATTR_ASPATH is present.

Depending the nexthop attribute on MP_REACH is not correct since and UPDATE
can in theory carry both MP_REACH nlri and old school IPv4 nlri.

rde_as4byte_fixup() should only fixup paths that have
 - ATTR_AS4_AGGREGATOR or ATTR_AS4_PATH present
 - ATTR_ASPATH must be present as well
 - no parse error (F_ATTR_PARSE_ERR)

The rde_as4byte_fixup() is entered all the time even for path that only
contain an ATTR_MP_UNREACH (which then could also include an ATTR_AS4_PATH
but no ATTR_ASPATH).

Reported by 7Asecurity
OK tb@
This commit is contained in:
claudio
2026-05-28 05:42:14 +00:00
parent 1617c35043
commit 545182717d
1 changed files with 11 additions and 9 deletions
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usr.sbin/bgpd/rde.c
+11 -9
View File
@@ -1,4 +1,4 @@
/* $OpenBSD: rde.c,v 1.703 2026/05/21 15:20:27 claudio Exp $ */
/* $OpenBSD: rde.c,v 1.704 2026/05/28 05:42:14 claudio Exp $ */
/*
* Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org>
@@ -57,7 +57,7 @@ void rde_update_withdraw(struct rde_peer *, uint32_t,
int rde_attr_parse(struct ibuf *, struct rde_peer *,
struct filterstate *, struct ibuf *, struct ibuf *);
int rde_attr_add(struct filterstate *, struct ibuf *);
uint8_t rde_attr_missing(struct rde_aspath *, int, uint16_t);
uint8_t rde_attr_missing(struct rde_aspath *, int, size_t);
int rde_get_mp_nexthop(struct ibuf *, uint8_t,
struct rde_peer *, struct filterstate *);
void rde_as4byte_fixup(struct rde_peer *, struct rde_aspath *);
@@ -2514,7 +2514,7 @@ rde_attr_add(struct filterstate *state, struct ibuf *buf)
}
uint8_t
rde_attr_missing(struct rde_aspath *a, int ebgp, uint16_t nlrilen)
rde_attr_missing(struct rde_aspath *a, int ebgp, size_t nlrilen)
{
/* ATTR_MP_UNREACH_NLRI may be sent alone */
if (nlrilen == 0 && a->flags & F_ATTR_MP_UNREACH &&
@@ -2525,8 +2525,7 @@ rde_attr_missing(struct rde_aspath *a, int ebgp, uint16_t nlrilen)
return (ATTR_ORIGIN);
if ((a->flags & F_ATTR_ASPATH) == 0)
return (ATTR_ASPATH);
if ((a->flags & F_ATTR_MP_REACH) == 0 &&
(a->flags & F_ATTR_NEXTHOP) == 0)
if (nlrilen != 0 && (a->flags & F_ATTR_NEXTHOP) == 0)
return (ATTR_NEXTHOP);
if (!ebgp)
if ((a->flags & F_ATTR_LOCALPREF) == 0)
@@ -2751,11 +2750,14 @@ rde_as4byte_fixup(struct rde_peer *peer, struct rde_aspath *a)
uint32_t as;
/*
* if either ATTR_AS4_AGGREGATOR or ATTR_AS4_PATH is present
* try to fixup the attributes.
* Do not fixup if F_ATTR_PARSE_ERR is set.
* Only fix up paths for which all these conditions hold:
* - ATTR_AS4_AGGREGATOR or ATTR_AS4_PATH is present
* - ATTR_ASPATH is present as well
* - no parse error (F_ATTR_PARSE_ERR)
*/
if (!(a->flags & F_ATTR_AS4BYTE_NEW) || a->flags & F_ATTR_PARSE_ERR)
if ((a->flags & F_ATTR_AS4BYTE_NEW) == 0 ||
(a->flags & F_ATTR_ASPATH) == 0 ||
a->flags & F_ATTR_PARSE_ERR)
return;
/* first get the attributes */