From 3060afc84d2c8a6fa79d588000331e94c36921ae Mon Sep 17 00:00:00 2001 From: Rajesh Varatharaj Date: Thu, 6 Mar 2025 16:57:18 -0800 Subject: [PATCH] zebra: Fix neigh delete causing heap-use-after-free error Issue: Not freeing the neighbor n within the same function can lead to memory leak. zebra_neigh_del_all() -> zebra_neigh_del() re lookup and free Fix: not accessing n after its freed. Directly free the neighbor entry (n) when its interface index matches ifp->ifindex. This fixes: ERROR: AddressSanitizer: heap-use-after-free on address 0x6070001052e8 at pc 0x7f6bf7d09ddb bp 0x7ffd3366a000 sp 0x7ffd33669ff0 READ of size 8 at 0x6070001052e8 thread T0 #0 0x7f6bf7d09dda in _rb_next lib/openbsd-tree.c:455 #1 0x55f95a307261 in zebra_neigh_rb_head_RB_NEXT zebra/zebra_neigh.h:34 #2 0x55f95a3082e9 in zebra_neigh_del_all zebra/zebra_neigh.c:162 #3 0x55f95a121ee7 in zebra_interface_down_update zebra/redistribute.c:571 #4 0x55f95a0f819d in if_down zebra/interface.c:1017 #5 0x55f95a0fe168 in zebra_if_dplane_ifp_handling zebra/interface.c:2102 #6 0x55f95a0ff10c in zebra_if_dplane_result zebra/interface.c:2241 #7 0x55f95a27ce9c in rib_process_dplane_results zebra/zebra_rib.c:5015 #8 0x7f6bf7da3ad9 in event_call lib/event.c:1984 #9 0x7f6bf7c62141 in frr_run lib/libfrr.c:1246 #10 0x55f95a11ca7f in main zebra/main.c:543 #11 0x7f6bf7029d8f in __libc_start_call_main ../sysdeps/nptl/libc_start_call_main.h:58 #12 0x7f6bf7029e3f in __libc_start_main_impl ../csu/libc-start.c:392 #13 0x55f95a0dd0b4 in _start (/usr/lib/frr/zebra+0x1a80b4) Ticket: #18047 Signed-off-by: Rajesh Varatharaj --- zebra/zebra_neigh.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/zebra/zebra_neigh.c b/zebra/zebra_neigh.c index a222e7f6e8..8a91f2719b 100644 --- a/zebra/zebra_neigh.c +++ b/zebra/zebra_neigh.c @@ -153,14 +153,18 @@ void zebra_neigh_del(struct interface *ifp, struct ipaddr *ip) /* kernel neigh delete all for a given interface */ void zebra_neigh_del_all(struct interface *ifp) { - struct zebra_neigh_ent *n, *nn; + struct zebra_neigh_ent *n, *next; if (IS_ZEBRA_DEBUG_NEIGH) zlog_debug("zebra neigh delete all for interface %s/%d", ifp->name, ifp->ifindex); - RB_FOREACH_SAFE (n, zebra_neigh_rb_head, &zneigh_info->neigh_rb_tree, nn) - zebra_neigh_del(ifp, &n->ip); + RB_FOREACH_SAFE (n, zebra_neigh_rb_head, &zneigh_info->neigh_rb_tree, next) { + if (n->ifindex == ifp->ifindex) { + /* Free the neighbor directly instead of looking it up again */ + zebra_neigh_free(n); + } + } } /* kernel neigh add */ -- 2.39.5