From 92fed37abc6cb732b99c39b87914cbe702758cd1 Mon Sep 17 00:00:00 2001 From: Donald Sharp Date: Sat, 2 Mar 2024 09:50:38 -0500 Subject: [PATCH] bgpd: Ensure community data is freed in some cases. Customer has this valgrind trace: Direct leak of 2829120 byte(s) in 70728 object(s) allocated from: 0 in community_new ../bgpd/bgp_community.c:39 1 in community_uniq_sort ../bgpd/bgp_community.c:170 2 in route_set_community ../bgpd/bgp_routemap.c:2342 3 in route_map_apply_ext ../lib/routemap.c:2673 4 in subgroup_announce_check ../bgpd/bgp_route.c:2367 5 in subgroup_process_announce_selected ../bgpd/bgp_route.c:2914 6 in group_announce_route_walkcb ../bgpd/bgp_updgrp_adv.c:199 7 in hash_walk ../lib/hash.c:285 8 in update_group_af_walk ../bgpd/bgp_updgrp.c:2061 9 in group_announce_route ../bgpd/bgp_updgrp_adv.c:1059 10 in bgp_process_main_one ../bgpd/bgp_route.c:3221 11 in bgp_process_wq ../bgpd/bgp_route.c:3221 12 in work_queue_run ../lib/workqueue.c:282 The above leak detected by valgrind was from a screenshot so I copied it by hand. Any mistakes in line numbers are purely from my transcription. Additionally this is against a slightly modified 8.5.1 version of FRR. Code inspection of 8.5.1 -vs- latest master shows the same problem exists. Code should be able to be followed from there to here. What is happening: There is a route-map being applied that modifes the outgoing community to a peer. This is saved in the attr copy created in subgroup_process_announce_selected. This community pointer is not interned. So the community->refcount is still 0. Normally when a prefix is announced, the attr and the prefix are placed on a adjency out structure where the attribute is interned. This will cause the community to be saved in the community hash list as well. In a non-normal operation when the decision to send is aborted after the route-map application, the attribute is just dropped and the pointer to the community is just dropped too, leading to situations where the memory is leaked. The usage of bgp suppress-fib would would be a case where the community is caused to be leaked. Additionally the previous commit where an unsuppress-map is used to modify the outgoing attribute but since unsuppress-map was not considered part of outgoing policy the attribute would be dropped as well. This pointer drop also extends to any dynamically allocated memory saved by the attribute pointer that was not interned yet as well. So let's modify the return case where the decision is made to not send the prefix to the peer to always just flush the attribute to ensure memory is not leaked. Fixes: #15459 Signed-off-by: Donald Sharp --- bgpd/bgp_conditional_adv.c | 5 +++-- bgpd/bgp_route.c | 24 ++++++++++++++++-------- bgpd/bgp_updgrp.h | 2 +- bgpd/bgp_updgrp_adv.c | 37 ++++++++++++++++++++----------------- 4 files changed, 40 insertions(+), 28 deletions(-) diff --git a/bgpd/bgp_conditional_adv.c b/bgpd/bgp_conditional_adv.c index 04a2cfc5e363..dbf58eb7fc94 100644 --- a/bgpd/bgp_conditional_adv.c +++ b/bgpd/bgp_conditional_adv.c @@ -137,8 +137,9 @@ static void bgp_conditional_adv_routes(struct peer *peer, afi_t afi, if (update_type == UPDATE_TYPE_ADVERTISE && subgroup_announce_check(dest, pi, subgrp, dest_p, &attr, &advmap_attr)) { - bgp_adj_out_set_subgroup(dest, subgrp, &attr, - pi); + if (!bgp_adj_out_set_subgroup(dest, subgrp, + &attr, pi)) + bgp_attr_flush(&attr); } else { /* If default originate is enabled for * the peer, do not send explicit diff --git a/bgpd/bgp_route.c b/bgpd/bgp_route.c index e15a3b375408..c1ac7b8b31a1 100644 --- a/bgpd/bgp_route.c +++ b/bgpd/bgp_route.c @@ -2811,9 +2811,9 @@ void subgroup_process_announce_selected(struct update_subgroup *subgrp, { const struct prefix *p; struct peer *onlypeer; - struct attr attr; afi_t afi; safi_t safi; + struct attr attr = { 0 }, *pattr = &attr; struct bgp *bgp; bool advertise; @@ -2843,22 +2843,30 @@ void subgroup_process_announce_selected(struct update_subgroup *subgrp, advertise = bgp_check_advertise(bgp, dest); if (selected) { - if (subgroup_announce_check(dest, selected, subgrp, p, &attr, + if (subgroup_announce_check(dest, selected, subgrp, p, pattr, NULL)) { /* Route is selected, if the route is already installed * in FIB, then it is advertised */ if (advertise) { - if (!bgp_check_withdrawal(bgp, dest)) - bgp_adj_out_set_subgroup( - dest, subgrp, &attr, selected); - else + if (!bgp_check_withdrawal(bgp, dest)) { + if (!bgp_adj_out_set_subgroup(dest, + subgrp, + pattr, + selected)) + bgp_attr_flush(pattr); + } else { bgp_adj_out_unset_subgroup( dest, subgrp, 1, addpath_tx_id); - } - } else + bgp_attr_flush(pattr); + } + } else + bgp_attr_flush(pattr); + } else { bgp_adj_out_unset_subgroup(dest, subgrp, 1, addpath_tx_id); + bgp_attr_flush(pattr); + } } /* If selected is NULL we must withdraw the path using addpath_tx_id */ diff --git a/bgpd/bgp_updgrp.h b/bgpd/bgp_updgrp.h index 56289d399d3b..57da41050523 100644 --- a/bgpd/bgp_updgrp.h +++ b/bgpd/bgp_updgrp.h @@ -454,7 +454,7 @@ extern struct bgp_adj_out *bgp_adj_out_alloc(struct update_subgroup *subgrp, extern void bgp_adj_out_remove_subgroup(struct bgp_dest *dest, struct bgp_adj_out *adj, struct update_subgroup *subgrp); -extern void bgp_adj_out_set_subgroup(struct bgp_dest *dest, +extern bool bgp_adj_out_set_subgroup(struct bgp_dest *dest, struct update_subgroup *subgrp, struct attr *attr, struct bgp_path_info *path); diff --git a/bgpd/bgp_updgrp_adv.c b/bgpd/bgp_updgrp_adv.c index d7cb51c66749..00a6f43bff85 100644 --- a/bgpd/bgp_updgrp_adv.c +++ b/bgpd/bgp_updgrp_adv.c @@ -449,7 +449,7 @@ bgp_advertise_clean_subgroup(struct update_subgroup *subgrp, return next; } -void bgp_adj_out_set_subgroup(struct bgp_dest *dest, +bool bgp_adj_out_set_subgroup(struct bgp_dest *dest, struct update_subgroup *subgrp, struct attr *attr, struct bgp_path_info *path) { @@ -469,7 +469,7 @@ void bgp_adj_out_set_subgroup(struct bgp_dest *dest, bgp = SUBGRP_INST(subgrp); if (DISABLE_BGP_ANNOUNCE) - return; + return false; /* Look for adjacency information. */ adj = adj_lookup( @@ -485,7 +485,7 @@ void bgp_adj_out_set_subgroup(struct bgp_dest *dest, bgp_addpath_id_for_peer(peer, afi, safi, &path->tx_addpath)); if (!adj) - return; + return false; subgrp->pscount++; } @@ -524,7 +524,7 @@ void bgp_adj_out_set_subgroup(struct bgp_dest *dest, * will never be able to coalesce the 3rd peer down */ subgrp->version = MAX(subgrp->version, dest->version); - return; + return false; } if (adj->adv) @@ -571,6 +571,8 @@ void bgp_adj_out_set_subgroup(struct bgp_dest *dest, bgp_adv_fifo_add_tail(&subgrp->sync->update, adv); subgrp->version = MAX(subgrp->version, dest->version); + + return true; } /* The only time 'withdraw' will be false is if we are sending @@ -799,7 +801,7 @@ void subgroup_announce_route(struct update_subgroup *subgrp) void subgroup_default_originate(struct update_subgroup *subgrp, int withdraw) { struct bgp *bgp; - struct attr attr; + struct attr attr = { 0 }; struct attr *new_attr = &attr; struct aspath *aspath; struct prefix p; @@ -933,18 +935,19 @@ void subgroup_default_originate(struct update_subgroup *subgrp, int withdraw) if (dest) { for (pi = bgp_dest_get_bgp_path_info(dest); pi; pi = pi->next) { - if (CHECK_FLAG(pi->flags, BGP_PATH_SELECTED)) - if (subgroup_announce_check( - dest, pi, subgrp, - bgp_dest_get_prefix(dest), - &attr, NULL)) { - struct attr *default_attr = - bgp_attr_intern(&attr); - - bgp_adj_out_set_subgroup( - dest, subgrp, - default_attr, pi); - } + if (!CHECK_FLAG(pi->flags, BGP_PATH_SELECTED)) + continue; + + if (subgroup_announce_check(dest, pi, subgrp, + bgp_dest_get_prefix( + dest), + &attr, NULL)) { + if (!bgp_adj_out_set_subgroup(dest, + subgrp, + &attr, pi)) + bgp_attr_flush(&attr); + } else + bgp_attr_flush(&attr); } bgp_dest_unlock_node(dest); }