From 59cda80fb6a0193d43d673c03f5e6ae1a454b299 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 | 19 +++++++++++++------ bgpd/bgp_updgrp.h | 2 +- bgpd/bgp_updgrp_adv.c | 29 ++++++++++++++++++----------- 4 files changed, 35 insertions(+), 20 deletions(-) diff --git a/bgpd/bgp_conditional_adv.c b/bgpd/bgp_conditional_adv.c index 24d822a745dc..edb9bc8bb76d 100644 --- a/bgpd/bgp_conditional_adv.c +++ b/bgpd/bgp_conditional_adv.c @@ -135,8 +135,9 @@ 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 f063fa96997d..b0818c07c516 100644 --- a/bgpd/bgp_route.c +++ b/bgpd/bgp_route.c @@ -2919,16 +2919,23 @@ void subgroup_process_announce_selected(struct update_subgroup *subgrp, struct attr *adv_attr = bgp_attr_intern(&attr); - bgp_adj_out_set_subgroup(dest, subgrp, - adv_attr, - selected); - } else + if (!bgp_adj_out_set_subgroup(dest, + subgrp, + adv_attr, + selected)) + bgp_attr_flush(&attr); + } else { bgp_adj_out_unset_subgroup( dest, subgrp, 1, addpath_tx_id); - } - } else + bgp_attr_flush(&attr); + } + } else + bgp_attr_flush(&attr); + } else { bgp_adj_out_unset_subgroup(dest, subgrp, 1, addpath_tx_id); + bgp_attr_flush(&attr); + } } /* 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 e27c1e7b6708..b7b6aa07e9f0 100644 --- a/bgpd/bgp_updgrp.h +++ b/bgpd/bgp_updgrp.h @@ -458,7 +458,7 @@ 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 de2b3206b7ae..1b93dc91428c 100644 --- a/bgpd/bgp_updgrp_adv.c +++ b/bgpd/bgp_updgrp_adv.c @@ -454,7 +454,7 @@ 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) { @@ -474,7 +474,7 @@ 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( @@ -490,7 +490,7 @@ 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++; } @@ -529,7 +529,7 @@ 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) @@ -576,6 +576,8 @@ 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 @@ -719,9 +721,10 @@ void subgroup_announce_table(struct update_subgroup *subgrp, struct attr *adv_attr = bgp_attr_intern(&attr); - bgp_adj_out_set_subgroup( + if (!bgp_adj_out_set_subgroup( dest, subgrp, adv_attr, - ri); + ri)) + bgp_attr_flush(adv_attr); } else bgp_adj_out_unset_subgroup( dest, subgrp, 1, @@ -950,7 +953,7 @@ 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 (CHECK_FLAG(pi->flags, BGP_PATH_SELECTED)) { if (subgroup_announce_check( dest, pi, subgrp, bgp_dest_get_prefix(dest), @@ -958,10 +961,14 @@ void subgroup_default_originate(struct update_subgroup *subgrp, int withdraw) struct attr *default_attr = bgp_attr_intern(&attr); - bgp_adj_out_set_subgroup( - dest, subgrp, - default_attr, pi); - } + if (!bgp_adj_out_set_subgroup( + dest, subgrp, + default_attr, pi)) + bgp_attr_flush( + &default_attr); + } else + bgp_attr_flush(&attr); + } } bgp_dest_unlock_node(dest); }