eabdullin
3ec6d7f6ae
- bgpd: Fix use beyond end of stream of labeled unicast parsing - bgpd: Ignore handling NLRIs if we received MP_UNREACH_NLRI - bgpd: Treat EOR as withdrawn to avoid unwanted handling of malformed attrs
90 lines
3.5 KiB
Diff
90 lines
3.5 KiB
Diff
From c37119df45bbf4ef713bc10475af2ee06e12f3bf Mon Sep 17 00:00:00 2001
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From: Donatas Abraitis <donatas@opensourcerouting.org>
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Date: Sun, 29 Oct 2023 22:44:45 +0200
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Subject: [PATCH] bgpd: Ignore handling NLRIs if we received MP_UNREACH_NLRI
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If we receive MP_UNREACH_NLRI, we should stop handling remaining NLRIs if
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no mandatory path attributes received.
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In other words, if MP_UNREACH_NLRI received, the remaining NLRIs should be handled
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as a new data, but without mandatory attributes, it's a malformed packet.
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In normal case, this MUST not happen at all, but to avoid crashing bgpd, we MUST
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handle that.
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Reported-by: Iggy Frankovic <iggyfran@amazon.com>
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Signed-off-by: Donatas Abraitis <donatas@opensourcerouting.org>
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---
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bgpd/bgp_attr.c | 19 ++++++++++---------
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bgpd/bgp_attr.h | 1 +
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bgpd/bgp_packet.c | 7 ++++++-
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3 files changed, 17 insertions(+), 10 deletions(-)
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diff --git a/bgpd/bgp_attr.c b/bgpd/bgp_attr.c
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index 1473dc772502..75aa2ac7cce6 100644
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--- a/bgpd/bgp_attr.c
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+++ b/bgpd/bgp_attr.c
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@@ -3086,15 +3086,6 @@ static int bgp_attr_check(struct peer *peer, struct attr *attr)
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if (CHECK_FLAG(peer->cap, PEER_CAP_RESTART_RCV) && !attr->flag)
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return BGP_ATTR_PARSE_WITHDRAW;
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- /* "An UPDATE message that contains the MP_UNREACH_NLRI is not required
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- to carry any other path attributes.", though if MP_REACH_NLRI or NLRI
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- are present, it should. Check for any other attribute being present
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- instead.
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- */
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- if ((!CHECK_FLAG(attr->flag, ATTR_FLAG_BIT(BGP_ATTR_MP_REACH_NLRI)) &&
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- CHECK_FLAG(attr->flag, ATTR_FLAG_BIT(BGP_ATTR_MP_UNREACH_NLRI))))
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- return BGP_ATTR_PARSE_PROCEED;
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-
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if (!CHECK_FLAG(attr->flag, ATTR_FLAG_BIT(BGP_ATTR_ORIGIN)))
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type = BGP_ATTR_ORIGIN;
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@@ -3113,6 +3104,16 @@ static int bgp_attr_check(struct peer *peer, struct attr *attr)
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&& !CHECK_FLAG(attr->flag, ATTR_FLAG_BIT(BGP_ATTR_LOCAL_PREF)))
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type = BGP_ATTR_LOCAL_PREF;
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+ /* An UPDATE message that contains the MP_UNREACH_NLRI is not required
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+ * to carry any other path attributes. Though if MP_REACH_NLRI or NLRI
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+ * are present, it should. Check for any other attribute being present
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+ * instead.
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+ */
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+ if (!CHECK_FLAG(attr->flag, ATTR_FLAG_BIT(BGP_ATTR_MP_REACH_NLRI)) &&
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+ CHECK_FLAG(attr->flag, ATTR_FLAG_BIT(BGP_ATTR_MP_UNREACH_NLRI)))
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+ return type ? BGP_ATTR_PARSE_MISSING_MANDATORY
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+ : BGP_ATTR_PARSE_PROCEED;
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+
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/* If any of the well-known mandatory attributes are not present
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* in an UPDATE message, then "treat-as-withdraw" MUST be used.
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*/
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diff --git a/bgpd/bgp_attr.h b/bgpd/bgp_attr.h
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index fc347e7a1b4b..d30155e6dba0 100644
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--- a/bgpd/bgp_attr.h
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+++ b/bgpd/bgp_attr.h
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@@ -379,6 +379,7 @@ enum bgp_attr_parse_ret {
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*/
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BGP_ATTR_PARSE_ERROR_NOTIFYPLS = -3,
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BGP_ATTR_PARSE_EOR = -4,
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+ BGP_ATTR_PARSE_MISSING_MANDATORY = -5,
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};
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struct bpacket_attr_vec_arr;
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diff --git a/bgpd/bgp_packet.c b/bgpd/bgp_packet.c
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index a7514a26aa64..5dc35157ebf6 100644
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--- a/bgpd/bgp_packet.c
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+++ b/bgpd/bgp_packet.c
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@@ -1873,7 +1873,12 @@ static int bgp_update_receive(struct peer *peer, bgp_size_t size)
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/* Network Layer Reachability Information. */
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update_len = end - stream_pnt(s);
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- if (update_len) {
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+ /* If we received MP_UNREACH_NLRI attribute, but also NLRIs, then
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+ * NLRIs should be handled as a new data. Though, if we received
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+ * NLRIs without mandatory attributes, they should be ignored.
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+ */
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+ if (update_len && attribute_len &&
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+ attr_parse_ret != BGP_ATTR_PARSE_MISSING_MANDATORY) {
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/* Set NLRI portion to structure. */
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nlris[NLRI_UPDATE].afi = AFI_IP;
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nlris[NLRI_UPDATE].safi = SAFI_UNICAST;
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