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quagga.30717
Quagga-CVE-2023-38802-bgpd-withdraw.bsc1213284....
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File Quagga-CVE-2023-38802-bgpd-withdraw.bsc1213284.patch of Package quagga.30717
From ab91e2aa78ce8464d01a57aebbc2dc5afc8cf119 Mon Sep 17 00:00:00 2001 From: Marius Tomaschewski <mt@suse.com> Date: Wed, 13 Sep 2023 12:30:52 +0200 Subject: [PATCH 1/4] bgpd: treat-as-withdraw for malformed attributes Upsteam: no References: CVE-2023-38802,bsc#1213284 Backported frr commit 4ba5a9c55f761e0c32d45050014b68e431d8b254 from https://github.com/FRRouting/frr/pull/5744: ``` Author: Donatas Abraitis <donatas.abraitis@gmail.com> Date: Wed Jan 29 15:09:37 2020 +0200 bgpd: Update some attributes how they are handled if malformed According to https://tools.ietf.org/html/rfc7606 some of the attributes MUST be handled as "treat-as-withdraw" approach. Signed-off-by: Donatas Abraitis <donatas.abraitis@gmail.com> ``` Signed-off-by: Marius Tomaschewski <mt@suse.com> diff --git a/bgpd/bgp_attr.c b/bgpd/bgp_attr.c index 43955125..1eb5bc5d 100644 --- a/bgpd/bgp_attr.c +++ b/bgpd/bgp_attr.c @@ -918,7 +918,7 @@ bgp_attr_malformed (struct bgp_attr_parser_args *args, u_char subcode, return BGP_ATTR_PARSE_PROCEED; /* Core attributes, particularly ones which may influence route - * selection, should always cause session resets + * selection, should be treat-as-withdraw. */ case BGP_ATTR_ORIGIN: case BGP_ATTR_AS_PATH: @@ -926,11 +926,12 @@ bgp_attr_malformed (struct bgp_attr_parser_args *args, u_char subcode, case BGP_ATTR_MULTI_EXIT_DISC: case BGP_ATTR_LOCAL_PREF: case BGP_ATTR_COMMUNITIES: + case BGP_ATTR_EXT_COMMUNITIES: case BGP_ATTR_ORIGINATOR_ID: case BGP_ATTR_CLUSTER_LIST: + return BGP_ATTR_PARSE_WITHDRAW; case BGP_ATTR_MP_REACH_NLRI: case BGP_ATTR_MP_UNREACH_NLRI: - case BGP_ATTR_EXT_COMMUNITIES: bgp_notify_send_with_data (peer, BGP_NOTIFY_UPDATE_ERR, subcode, notify_datap, length); return BGP_ATTR_PARSE_ERROR; @@ -1169,23 +1170,19 @@ bgp_attr_aspath_check (struct peer *const peer, struct attr *const attr) (peer->sort == BGP_PEER_EBGP && aspath_confed_check (attr->aspath))) { zlog (peer->log, LOG_ERR, "Malformed AS path from %s", peer->host); - bgp_notify_send (peer, BGP_NOTIFY_UPDATE_ERR, - BGP_NOTIFY_UPDATE_MAL_AS_PATH); - return BGP_ATTR_PARSE_ERROR; + return BGP_ATTR_PARSE_WITHDRAW; } /* First AS check for EBGP. */ if (bgp != NULL && bgp_flag_check (bgp, BGP_FLAG_ENFORCE_FIRST_AS)) { if (peer->sort == BGP_PEER_EBGP - && ! aspath_firstas_check (attr->aspath, peer->as)) - { - zlog (peer->log, LOG_ERR, - "%s incorrect first AS (must be %u)", peer->host, peer->as); - bgp_notify_send (peer, BGP_NOTIFY_UPDATE_ERR, - BGP_NOTIFY_UPDATE_MAL_AS_PATH); - return BGP_ATTR_PARSE_ERROR; - } + && ! aspath_firstas_check (attr->aspath, peer->as)) + { + zlog (peer->log, LOG_ERR, + "%s incorrect first AS (must be %u)", peer->host, peer->as); + return BGP_ATTR_PARSE_WITHDRAW; + } } /* local-as prepend */ @@ -1309,8 +1306,12 @@ bgp_attr_local_pref (struct bgp_attr_parser_args *args) struct attr *const attr = args->attr; const bgp_size_t length = args->length; - /* Length check. */ - if (length != 4) + /* if received from an internal neighbor, it SHALL be considered + * malformed if its length is not equal to 4. If malformed, the + * UPDATE message SHALL be handled using the approach of "treat-as- + * withdraw". + */ + if (peer->sort == BGP_PEER_IBGP && length != 4) { zlog (peer->log, LOG_ERR, "LOCAL_PREF attribute length isn't 4 [%u]", length); @@ -1372,7 +1373,8 @@ bgp_attr_aggregator (struct bgp_attr_parser_args *args) struct attr_extra *attre = bgp_attr_extra_get (attr); /* peer with AS4 will send 4 Byte AS, peer without will send 2 Byte */ - if (CHECK_FLAG (peer->cap, PEER_CAP_AS4_RCV)) + if (CHECK_FLAG (peer->cap, PEER_CAP_AS4_RCV) + && CHECK_FLAG(peer->cap, PEER_CAP_AS4_ADV)) wantedlen = 8; if (length != wantedlen) @@ -1551,6 +1553,9 @@ bgp_attr_community (struct bgp_attr_parser_args *args) /* XXX: fix community_parse to use stream API and remove this */ stream_forward_getp (peer->ibuf, length); + /* The Community attribute SHALL be considered malformed if its + * length is not a non-zero multiple of 4. + */ if (!attr->community) return bgp_attr_malformed (args, BGP_NOTIFY_UPDATE_OPT_ATTR_ERR, @@ -1569,7 +1574,11 @@ bgp_attr_originator_id (struct bgp_attr_parser_args *args) struct attr *const attr = args->attr; const bgp_size_t length = args->length; - /* Length check. */ + /* if received from an internal neighbor, it SHALL be considered + * malformed if its length is not equal to 4. If malformed, the + * UPDATE message SHALL be handled using the approach of "treat-as- + * withdraw". + */ if (length != 4) { zlog (peer->log, LOG_ERR, "Bad originator ID length %d", length); @@ -1595,7 +1604,11 @@ bgp_attr_cluster_list (struct bgp_attr_parser_args *args) struct attr *const attr = args->attr; const bgp_size_t length = args->length; - /* Check length. */ + /* if received from an internal neighbor, it SHALL be considered + * malformed if its length is not a non-zero multiple of 4. If + * malformed, the UPDATE message SHALL be handled using the approach + * of "treat-as-withdraw". + */ if (length % 4) { zlog (peer->log, LOG_ERR, "Bad cluster list length %d", length); @@ -1816,7 +1829,10 @@ bgp_attr_ext_communities (struct bgp_attr_parser_args *args) ecommunity_parse ((u_int8_t *)stream_pnt (peer->ibuf), length); /* XXX: fix ecommunity_parse to use stream API */ stream_forward_getp (peer->ibuf, length); - + + /* The Extended Community attribute SHALL be considered malformed if + * its length is not a non-zero multiple of 8. + */ if (!attr->extra->ecommunity) return bgp_attr_malformed (args, BGP_NOTIFY_UPDATE_OPT_ATTR_ERR, @@ -2047,16 +2063,16 @@ 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; + /* If any of the well-known mandatory attributes are not present + * in an UPDATE message, then "treat-as-withdraw" MUST be used. + */ if (type) { zlog (peer->log, LOG_WARNING, "%s Missing well-known attribute %d / %s", peer->host, type, LOOKUP (attr_str, type)); - bgp_notify_send_with_data (peer, - BGP_NOTIFY_UPDATE_ERR, - BGP_NOTIFY_UPDATE_MISS_ATTR, - &type, 1); - return BGP_ATTR_PARSE_ERROR; + + return BGP_ATTR_PARSE_WITHDRAW; } return BGP_ATTR_PARSE_PROCEED; } diff --git a/tests/aspath_test.c b/tests/aspath_test.c index 5a0899ec..4f752af1 100644 --- a/tests/aspath_test.c +++ b/tests/aspath_test.c @@ -637,7 +637,7 @@ static struct aspath_tests { "4b AS4_PATH w/o AS_PATH", &test_segments[6], NULL, - AS4_DATA, -1, + AS4_DATA, -2, PEER_CAP_AS4_ADV, { COMMON_ATTRS, BGP_ATTR_FLAG_TRANS|BGP_ATTR_FLAG_OPTIONAL, -- 2.35.3 From d286bd5bef266b0b1cde75359d96a447eab1cf0f Mon Sep 17 00:00:00 2001 From: Marius Tomaschewski <mt@suse.com> Date: Wed, 13 Sep 2023 12:30:52 +0200 Subject: [PATCH 2/4] bgpd: treat 0-length cluster_list as withdraw Upsteam: no References: CVE-2023-38802,bsc#1213284 Backported frr commit 33ba22c24874b12916c4ea0fc57e9e188ce7c18d from https://github.com/FRRouting/frr/pull/6167: ``` Author: Quentin Young <qlyoung@cumulusnetworks.com> Date: Mon Apr 6 12:30:35 2020 -0400 bgpd: treat 0-length cluster_list as withdraw See source comment... Signed-off-by: Quentin Young <qlyoung@cumulusnetworks.com> ``` Signed-off-by: Marius Tomaschewski <mt@suse.com> diff --git a/bgpd/bgp_attr.c b/bgpd/bgp_attr.c index 1eb5bc5d..e3a7546a 100644 --- a/bgpd/bgp_attr.c +++ b/bgpd/bgp_attr.c @@ -1609,7 +1609,7 @@ bgp_attr_cluster_list (struct bgp_attr_parser_args *args) * malformed, the UPDATE message SHALL be handled using the approach * of "treat-as-withdraw". */ - if (length % 4) + if (length == 0 || length % 4) { zlog (peer->log, LOG_ERR, "Bad cluster list length %d", length); -- 2.35.3 From 8a6dc173b2afa1b8904787b02635a724f098da6b Mon Sep 17 00:00:00 2001 From: Marius Tomaschewski <mt@suse.com> Date: Wed, 13 Sep 2023 12:30:52 +0200 Subject: [PATCH 3/4] bgpd: Treat-as-withdraw if [e]community length is zero Upsteam: no References: CVE-2023-38802,bsc#1213284 Backported frr commit 6680b5508c8d37b61910ee141d9696bd3d10315e from https://github.com/FRRouting/frr/pull/6173: ``` Author: Donatas Abraitis <donatas.abraitis@gmail.com> Date: Tue Apr 7 10:08:16 2020 +0300 bgpd: Treat-as-withdraw if [el]community length is zero Signed-off-by: Donatas Abraitis <donatas.abraitis@gmail.com> ``` Signed-off-by: Marius Tomaschewski <mt@suse.com> diff --git a/bgpd/bgp_attr.c b/bgpd/bgp_attr.c index e3a7546a..017ac2b6 100644 --- a/bgpd/bgp_attr.c +++ b/bgpd/bgp_attr.c @@ -1544,7 +1544,8 @@ bgp_attr_community (struct bgp_attr_parser_args *args) if (length == 0) { attr->community = NULL; - return BGP_ATTR_PARSE_PROCEED; + return bgp_attr_malformed(args, BGP_NOTIFY_UPDATE_OPT_ATTR_ERR, + args->total); } attr->community = @@ -1822,7 +1823,8 @@ bgp_attr_ext_communities (struct bgp_attr_parser_args *args) if (attr->extra) attr->extra->ecommunity = NULL; /* Empty extcomm doesn't seem to be invalid per se */ - return BGP_ATTR_PARSE_PROCEED; + return bgp_attr_malformed(args, BGP_NOTIFY_UPDATE_OPT_ATTR_ERR, + args->total); } (bgp_attr_extra_get (attr))->ecommunity = -- 2.35.3 From e35b24f747ffb3491041e31c5a06c14fe21b751e Mon Sep 17 00:00:00 2001 From: Marius Tomaschewski <mt@suse.com> Date: Fri, 15 Sep 2023 10:34:20 +0200 Subject: [PATCH 4/4] bgpd: treat-as-withdraw for tunnel encapsulation Upsteam: no References: CVE-2023-38802,bsc#1213284 Backported frr commit bcb6b58d9530173df41d3a3cbc4c600ee0b4b186 from https://github.com/FRRouting/frr/pull/14295 (CVE-2023-38802): ``` bgpd: Use treat-as-withdraw for tunnel encapsulation attribute Before this path we used session reset method, which is discouraged by rfc7606. Handle this as rfc requires. Signed-off-by: Donatas Abraitis <donatas@opensourcerouting.org> ``` Signed-off-by: Marius Tomaschewski <mt@suse.com> diff --git a/bgpd/bgp_attr.c b/bgpd/bgp_attr.c index 017ac2b6..fce4b542 100644 --- a/bgpd/bgp_attr.c +++ b/bgpd/bgp_attr.c @@ -929,6 +929,7 @@ bgp_attr_malformed (struct bgp_attr_parser_args *args, u_char subcode, case BGP_ATTR_EXT_COMMUNITIES: case BGP_ATTR_ORIGINATOR_ID: case BGP_ATTR_CLUSTER_LIST: + case BGP_ATTR_ENCAP: return BGP_ATTR_PARSE_WITHDRAW; case BGP_ATTR_MP_REACH_NLRI: case BGP_ATTR_MP_UNREACH_NLRI: @@ -1847,31 +1848,24 @@ bgp_attr_ext_communities (struct bgp_attr_parser_args *args) /* Parse Tunnel Encap attribute in an UPDATE */ static int -bgp_attr_encap( - uint8_t type, - struct peer *peer, /* IN */ - bgp_size_t length, /* IN: attr's length field */ - struct attr *attr, /* IN: caller already allocated */ - u_char flag, /* IN: attr's flags field */ - u_char *startp) -{ - bgp_size_t total; +bgp_attr_encap(struct bgp_attr_parser_args *args) +{ struct attr_extra *attre = NULL; struct bgp_attr_encap_subtlv *stlv_last = NULL; uint16_t tunneltype; - - total = length + (CHECK_FLAG (flag, BGP_ATTR_FLAG_EXTLEN) ? 4 : 3); + struct peer *const peer = args->peer; + struct attr *const attr = args->attr; + bgp_size_t length = args->length; + uint8_t type = args->type; + uint8_t flag = args->flags; if (!CHECK_FLAG(flag, BGP_ATTR_FLAG_TRANS) || !CHECK_FLAG(flag, BGP_ATTR_FLAG_OPTIONAL)) { zlog (peer->log, LOG_ERR, "Tunnel Encap attribute flag isn't optional and transitive %d", flag); - bgp_notify_send_with_data (peer, - BGP_NOTIFY_UPDATE_ERR, - BGP_NOTIFY_UPDATE_ATTR_FLAG_ERR, - startp, total); - return -1; + return bgp_attr_malformed(args, BGP_NOTIFY_UPDATE_OPT_ATTR_ERR, + args->total); } if (BGP_ATTR_ENCAP == type) { @@ -1881,11 +1875,8 @@ bgp_attr_encap( if (length < 4) { zlog (peer->log, LOG_ERR, "Tunnel Encap attribute not long enough to contain outer T,L"); - bgp_notify_send_with_data(peer, - BGP_NOTIFY_UPDATE_ERR, - BGP_NOTIFY_UPDATE_OPT_ATTR_ERR, - startp, total); - return -1; + return bgp_attr_malformed(args, BGP_NOTIFY_UPDATE_OPT_ATTR_ERR, + args->total); } tunneltype = stream_getw (BGP_INPUT (peer)); tlv_length = stream_getw (BGP_INPUT (peer)); @@ -1912,11 +1903,8 @@ bgp_attr_encap( zlog (peer->log, LOG_ERR, "Tunnel Encap attribute sub-tlv length %d exceeds remaining length %d", sublength, length); - bgp_notify_send_with_data (peer, - BGP_NOTIFY_UPDATE_ERR, - BGP_NOTIFY_UPDATE_OPT_ATTR_ERR, - startp, total); - return -1; + return bgp_attr_malformed(args, BGP_NOTIFY_UPDATE_OPT_ATTR_ERR, + args->total); } /* alloc and copy sub-tlv */ @@ -1953,11 +1941,8 @@ bgp_attr_encap( /* spurious leftover data */ zlog (peer->log, LOG_ERR, "Tunnel Encap attribute length is bad: %d leftover octets", length); - bgp_notify_send_with_data (peer, - BGP_NOTIFY_UPDATE_ERR, - BGP_NOTIFY_UPDATE_OPT_ATTR_ERR, - startp, total); - return -1; + return bgp_attr_malformed(args, BGP_NOTIFY_UPDATE_OPT_ATTR_ERR, + args->total); } return 0; @@ -2266,7 +2251,7 @@ bgp_attr_parse (struct peer *peer, struct attr *attr, bgp_size_t size, ret = bgp_attr_ext_communities (&attr_args); break; case BGP_ATTR_ENCAP: - ret = bgp_attr_encap (type, peer, length, attr, flag, startp); + ret = bgp_attr_encap (&attr_args); break; default: ret = bgp_attr_unknown (&attr_args); -- 2.35.3
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