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- bgpd: Flowspec overflow issue

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- 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- bgpd: Treat EOR as withdrawn to avoid unwanted handling of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
This commit is contained in:
eabdullin 2024-01-25 11:27:22 +03:00
parent 80b0458f9d
commit 3ec6d7f6ae
5 changed files with 300 additions and 1 deletions
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34
SOURCES/CVE-2023-38406.patch Normal file
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@ -0,0 +1,34 @@
From 0b999c886e241c52bd1f7ef0066700e4b618ebb3 Mon Sep 17 00:00:00 2001
From: Donald Sharp <sharpd@nvidia.com>
Date: Thu, 23 Feb 2023 13:29:32 -0500
Subject: [PATCH] bgpd: Flowspec overflow issue
According to the flowspec RFC 8955 a flowspec nlri is <length, <nlri data>>
Specifying 0 as a length makes BGP get all warm on the inside. Which
in this case is not a good thing at all. Prevent warmth, stay cold
on the inside.
Reported-by: Iggy Frankovic <iggyfran@amazon.com>
Signed-off-by: Donald Sharp <sharpd@nvidia.com>
---
bgpd/bgp_flowspec.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/bgpd/bgp_flowspec.c b/bgpd/bgp_flowspec.c
index 8d5ca5e77779..f9debe43cd45 100644
--- a/bgpd/bgp_flowspec.c
+++ b/bgpd/bgp_flowspec.c
@@ -127,6 +127,13 @@ int bgp_nlri_parse_flowspec(struct peer *peer, struct attr *attr,
psize);
return BGP_NLRI_PARSE_ERROR_PACKET_OVERFLOW;
}
+
+ if (psize == 0) {
+ flog_err(EC_BGP_FLOWSPEC_PACKET,
+ "Flowspec NLRI length 0 which makes no sense");
+ return BGP_NLRI_PARSE_ERROR_PACKET_OVERFLOW;
+ }
+
if (bgp_fs_nlri_validate(pnt, psize, afi) < 0) {
flog_err(
EC_BGP_FLOWSPEC_PACKET,

55
SOURCES/CVE-2023-38407.patch Normal file
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@ -0,0 +1,55 @@
From ab362eae68edec12c175d9bc488bcc3f8b73d36f Mon Sep 17 00:00:00 2001
From: Donald Sharp <sharpd@nvidia.com>
Date: Fri, 3 Mar 2023 21:58:33 -0500
Subject: [PATCH] bgpd: Fix use beyond end of stream of labeled unicast parsing
Fixes a couple crashes associated with attempting to read
beyond the end of the stream.
Reported-by: Iggy Frankovic <iggyfran@amazon.com>
Signed-off-by: Donald Sharp <sharpd@nvidia.com>
(cherry picked from commit 7404a914b0cafe046703c8381903a80d3def8f8b)
---
bgpd/bgp_label.c | 15 +++++++++++++++
1 file changed, 15 insertions(+)
diff --git a/bgpd/bgp_label.c b/bgpd/bgp_label.c
index 38f34a892702..64d1ff70ca22 100644
--- a/bgpd/bgp_label.c
+++ b/bgpd/bgp_label.c
@@ -297,6 +297,9 @@ static int bgp_nlri_get_labels(struct peer *peer, uint8_t *pnt, uint8_t plen,
uint8_t llen = 0;
uint8_t label_depth = 0;
+ if (plen < BGP_LABEL_BYTES)
+ return 0;
+
for (; data < lim; data += BGP_LABEL_BYTES) {
memcpy(label, data, BGP_LABEL_BYTES);
llen += BGP_LABEL_BYTES;
@@ -359,6 +362,9 @@ int bgp_nlri_parse_label(struct peer *peer, struct attr *attr,
memcpy(&addpath_id, pnt, BGP_ADDPATH_ID_LEN);
addpath_id = ntohl(addpath_id);
pnt += BGP_ADDPATH_ID_LEN;
+
+ if (pnt >= lim)
+ return BGP_NLRI_PARSE_ERROR_PACKET_OVERFLOW;
}
/* Fetch prefix length. */
@@ -377,6 +383,15 @@ int bgp_nlri_parse_label(struct peer *peer, struct attr *attr,
/* Fill in the labels */
llen = bgp_nlri_get_labels(peer, pnt, psize, &label);
+ if (llen == 0) {
+ flog_err(
+ EC_BGP_UPDATE_RCV,
+ "%s [Error] Update packet error (wrong label length 0)",
+ peer->host);
+ bgp_notify_send(peer, BGP_NOTIFY_UPDATE_ERR,
+ BGP_NOTIFY_UPDATE_INVAL_NETWORK);
+ return BGP_NLRI_PARSE_ERROR_LABEL_LENGTH;
+ }
p.prefixlen = prefixlen - BSIZE(llen);
/* There needs to be at least one label */

89
SOURCES/CVE-2023-47234.patch Normal file
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@ -0,0 +1,89 @@
From c37119df45bbf4ef713bc10475af2ee06e12f3bf Mon Sep 17 00:00:00 2001
From: Donatas Abraitis <donatas@opensourcerouting.org>
Date: Sun, 29 Oct 2023 22:44:45 +0200
Subject: [PATCH] bgpd: Ignore handling NLRIs if we received MP_UNREACH_NLRI
If we receive MP_UNREACH_NLRI, we should stop handling remaining NLRIs if
no mandatory path attributes received.
In other words, if MP_UNREACH_NLRI received, the remaining NLRIs should be handled
as a new data, but without mandatory attributes, it's a malformed packet.
In normal case, this MUST not happen at all, but to avoid crashing bgpd, we MUST
handle that.
Reported-by: Iggy Frankovic <iggyfran@amazon.com>
Signed-off-by: Donatas Abraitis <donatas@opensourcerouting.org>
---
bgpd/bgp_attr.c | 19 ++++++++++---------
bgpd/bgp_attr.h | 1 +
bgpd/bgp_packet.c | 7 ++++++-
3 files changed, 17 insertions(+), 10 deletions(-)
diff --git a/bgpd/bgp_attr.c b/bgpd/bgp_attr.c
index 1473dc772502..75aa2ac7cce6 100644
--- a/bgpd/bgp_attr.c
+++ b/bgpd/bgp_attr.c
@@ -3086,15 +3086,6 @@ static int bgp_attr_check(struct peer *peer, struct attr *attr)
if (CHECK_FLAG(peer->cap, PEER_CAP_RESTART_RCV) && !attr->flag)
return BGP_ATTR_PARSE_WITHDRAW;
- /* "An UPDATE message that contains the MP_UNREACH_NLRI is not required
- to carry any other path attributes.", though if MP_REACH_NLRI or NLRI
- are present, it should. Check for any other attribute being present
- instead.
- */
- if ((!CHECK_FLAG(attr->flag, ATTR_FLAG_BIT(BGP_ATTR_MP_REACH_NLRI)) &&
- CHECK_FLAG(attr->flag, ATTR_FLAG_BIT(BGP_ATTR_MP_UNREACH_NLRI))))
- return BGP_ATTR_PARSE_PROCEED;
-
if (!CHECK_FLAG(attr->flag, ATTR_FLAG_BIT(BGP_ATTR_ORIGIN)))
type = BGP_ATTR_ORIGIN;
@@ -3113,6 +3104,16 @@ static int bgp_attr_check(struct peer *peer, struct attr *attr)
&& !CHECK_FLAG(attr->flag, ATTR_FLAG_BIT(BGP_ATTR_LOCAL_PREF)))
type = BGP_ATTR_LOCAL_PREF;
+ /* An UPDATE message that contains the MP_UNREACH_NLRI is not required
+ * to carry any other path attributes. Though if MP_REACH_NLRI or NLRI
+ * are present, it should. Check for any other attribute being present
+ * instead.
+ */
+ if (!CHECK_FLAG(attr->flag, ATTR_FLAG_BIT(BGP_ATTR_MP_REACH_NLRI)) &&
+ CHECK_FLAG(attr->flag, ATTR_FLAG_BIT(BGP_ATTR_MP_UNREACH_NLRI)))
+ return type ? BGP_ATTR_PARSE_MISSING_MANDATORY
+ : BGP_ATTR_PARSE_PROCEED;
+
/* If any of the well-known mandatory attributes are not present
* in an UPDATE message, then "treat-as-withdraw" MUST be used.
*/
diff --git a/bgpd/bgp_attr.h b/bgpd/bgp_attr.h
index fc347e7a1b4b..d30155e6dba0 100644
--- a/bgpd/bgp_attr.h
+++ b/bgpd/bgp_attr.h
@@ -379,6 +379,7 @@ enum bgp_attr_parse_ret {
*/
BGP_ATTR_PARSE_ERROR_NOTIFYPLS = -3,
BGP_ATTR_PARSE_EOR = -4,
+ BGP_ATTR_PARSE_MISSING_MANDATORY = -5,
};
struct bpacket_attr_vec_arr;
diff --git a/bgpd/bgp_packet.c b/bgpd/bgp_packet.c
index a7514a26aa64..5dc35157ebf6 100644
--- a/bgpd/bgp_packet.c
+++ b/bgpd/bgp_packet.c
@@ -1873,7 +1873,12 @@ static int bgp_update_receive(struct peer *peer, bgp_size_t size)
/* Network Layer Reachability Information. */
update_len = end - stream_pnt(s);
- if (update_len) {
+ /* If we received MP_UNREACH_NLRI attribute, but also NLRIs, then
+ * NLRIs should be handled as a new data. Though, if we received
+ * NLRIs without mandatory attributes, they should be ignored.
+ */
+ if (update_len && attribute_len &&
+ attr_parse_ret != BGP_ATTR_PARSE_MISSING_MANDATORY) {
/* Set NLRI portion to structure. */
nlris[NLRI_UPDATE].afi = AFI_IP;
nlris[NLRI_UPDATE].safi = SAFI_UNICAST;

105
SOURCES/CVE-2023-47235.patch Normal file
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@ -0,0 +1,105 @@
From 6814f2e0138a6ea5e1f83bdd9085d9a77999900b Mon Sep 17 00:00:00 2001
From: Donatas Abraitis <donatas@opensourcerouting.org>
Date: Fri, 27 Oct 2023 11:56:45 +0300
Subject: [PATCH] bgpd: Treat EOR as withdrawn to avoid unwanted handling of
malformed attrs
Treat-as-withdraw, otherwise if we just ignore it, we will pass it to be
processed as a normal UPDATE without mandatory attributes, that could lead
to harmful behavior. In this case, a crash for route-maps with the configuration
such as:
```
router bgp 65001
no bgp ebgp-requires-policy
neighbor 127.0.0.1 remote-as external
neighbor 127.0.0.1 passive
neighbor 127.0.0.1 ebgp-multihop
neighbor 127.0.0.1 disable-connected-check
neighbor 127.0.0.1 update-source 127.0.0.2
neighbor 127.0.0.1 timers 3 90
neighbor 127.0.0.1 timers connect 1
!
address-family ipv4 unicast
neighbor 127.0.0.1 addpath-tx-all-paths
neighbor 127.0.0.1 default-originate
neighbor 127.0.0.1 route-map RM_IN in
exit-address-family
exit
!
route-map RM_IN permit 10
set as-path prepend 200
exit
```
Send a malformed optional transitive attribute:
```
import socket
import time
OPEN = (b"\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff"
b"\xff\xff\x00\x62\x01\x04\xfd\xea\x00\x5a\x0a\x00\x00\x01\x45\x02"
b"\x06\x01\x04\x00\x01\x00\x01\x02\x02\x02\x00\x02\x02\x46\x00\x02"
b"\x06\x41\x04\x00\x00\xfd\xea\x02\x02\x06\x00\x02\x06\x45\x04\x00"
b"\x01\x01\x03\x02\x0e\x49\x0c\x0a\x64\x6f\x6e\x61\x74\x61\x73\x2d"
b"\x70\x63\x00\x02\x04\x40\x02\x00\x78\x02\x09\x47\x07\x00\x01\x01"
b"\x80\x00\x00\x00")
KEEPALIVE = (b"\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff"
b"\xff\xff\xff\xff\xff\xff\x00\x13\x04")
UPDATE = bytearray.fromhex("ffffffffffffffffffffffffffffffff002b0200000003c0ff00010100eb00ac100b0b001ad908ac100b0b")
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect(('127.0.0.2', 179))
s.send(OPEN)
data = s.recv(1024)
s.send(KEEPALIVE)
data = s.recv(1024)
s.send(UPDATE)
data = s.recv(1024)
time.sleep(100)
s.close()
```
Reported-by: Iggy Frankovic <iggyfran@amazon.com>
Signed-off-by: Donatas Abraitis <donatas@opensourcerouting.org>
---
bgpd/bgp_attr.c | 15 ++++++++++++---
1 file changed, 12 insertions(+), 3 deletions(-)
diff --git a/bgpd/bgp_attr.c b/bgpd/bgp_attr.c
index cf2dbe65b805..1473dc772502 100644
--- a/bgpd/bgp_attr.c
+++ b/bgpd/bgp_attr.c
@@ -3079,9 +3079,12 @@ static int bgp_attr_check(struct peer *peer, struct attr *attr)
uint8_t type = 0;
/* BGP Graceful-Restart End-of-RIB for IPv4 unicast is signaled as an
- * empty UPDATE. */
+ * empty UPDATE. Treat-as-withdraw, otherwise if we just ignore it,
+ * we will pass it to be processed as a normal UPDATE without mandatory
+ * attributes, that could lead to harmful behavior.
+ */
if (CHECK_FLAG(peer->cap, PEER_CAP_RESTART_RCV) && !attr->flag)
- return BGP_ATTR_PARSE_PROCEED;
+ return BGP_ATTR_PARSE_WITHDRAW;
/* "An UPDATE message that contains the MP_UNREACH_NLRI is not required
to carry any other path attributes.", though if MP_REACH_NLRI or NLRI
@@ -3507,7 +3510,13 @@ done:
aspath_unintern(&as4_path);
transit = bgp_attr_get_transit(attr);
- if (ret != BGP_ATTR_PARSE_ERROR) {
+ /* If we received an UPDATE with mandatory attributes, then
+ * the unrecognized transitive optional attribute of that
+ * path MUST be passed. Otherwise, it's an error, and from
+ * security perspective it might be very harmful if we continue
+ * here with the unrecognized attributes.
+ */
+ if (ret == BGP_ATTR_PARSE_PROCEED) {
/* Finally intern unknown attribute. */
if (transit)
bgp_attr_set_transit(attr, transit_intern(transit));

18
SPECS/frr.spec
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@ -7,7 +7,7 @@
Name: frr
Version: 8.3.1
Release: 11%{?checkout}%{?dist}.1.alma.1
Release: 11%{?checkout}%{?dist}.2.alma.1
Summary: Routing daemon
License: GPLv2+
URL: http://www.frrouting.org
@ -80,6 +80,15 @@ Patch0012: 0012-bfd-not-working-in-vrf.patch
Patch0013: CVE-2023-38802.patch
# https://github.com/FRRouting/frr/commit/767aaa3a80489bfc4ff097f932fc347e3db25b89
Patch0014: bgpd-Do-not-explicitly-print-MAXTTL.patch
# https://github.com/FRRouting/frr/commit/6814f2e0138a6ea5e1f83bdd9085d9a77999900b
Patch0015: CVE-2023-47235.patch
# https://github.com/FRRouting/frr/commit/c37119df45bbf4ef713bc10475af2ee06e12f3bf
Patch0016: CVE-2023-47234.patch
# https://github.com/FRRouting/frr/pull/12884/commits/0b999c886e241c52bd1f7ef0066700e4b618ebb3
Patch0017: CVE-2023-38406.patch
# https://github.com/FRRouting/frr/pull/12956/commits/ab362eae68edec12c175d9bc488bcc3f8b73d36f
Patch0018: CVE-2023-38407.patch
%description
FRRouting is free software that manages TCP/IP based routing protocols. It takes
@ -285,6 +294,13 @@ make check PYTHON=%{__python3}
%endif
%changelog
* Thu Jan 25 2024 Eduard Abdullin <eabdullin@almalinux.org> - 8.3.1-11.2.alma.1
- bgpd: Flowspec overflow issue
- 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
* Wed Dec 13 2023 Eduard Abdullin <eabdullin@almalinux.org> - 8.3.1-11.1.alma.1
- bgpd: Do not explicitly print MAXTTL value for ebgp-multihop
vty output