Again adding forgotten tag: Reported-at: https://mail.openvswitch.org/pipermail/ovs-dev/2024-April/413198.html
regards, Vladislav Odintsov On 22.05.2024, 15:19, "Vladislav Odintsov" <[email protected]> wrote: These structure members are read in pinctrl_handler() in a separare thread. This is unsafe: when IDL is re-connected or some IDL objects are freed after svc_monitors list with svc_monitor structures, which point to sbrec_service_monitor is initialized, sb_svc_mon structure property can point to wrong address, which then leads to segmentation fault in svc_monitor_send_tcp_health_check__() and svc_monitor_send_udp_health_check() on accessing svc_mon->sb_svc_mon. Imagine situation: Main ovn-controller thread: 1. Connects to SB and fills IDL with DB contents. 2. run pinctrl_run() with pinctrl mutex and sync_svc_monitors() as a part of it. 3. Release mutex. ... 4. Loss of OVNSB connection for any reason (network outage/inactivity probe timeout/etc), start new main-loop iteration, re-initialize IDL in ovsdb_idl_run() (which probably will destroy previous IDL objects). ... pinctrl thread: 5. Awake from poll_block(). ... run new iteration in its main loop ... 6. Acquire mutex lock. 7. Run svc_monitors_run(), run svc_monitor_send_tcp_health_check__() or svc_monitor_send_udp_health_check(), which try to access IDL objects with outdated pointers. 8. Segmentation fault: Stack trace of thread 212406: __GI_strlen (libc.so.6) inet_pton (libc.so.6) ip_parse (ovn-controller) svc_monitor_send_tcp_health_check__.part.37 (ovn-controller) svc_monitor_send_health_check (ovn-controller) pinctrl_handler (ovn-controller) ovsthread_wrapper (ovn-controller) start_thread (libpthread.so.0) __clone (libc.so.6) This patch removes unsafe access to IDL objects from pinctrl thread. New svc_monitor structure members are used to store needed data. CC: Numan Siddique <[email protected]> Acked-by: Ales Musil <[email protected]> Fixes: 8be01f4a5329 ("Send service monitor health checks") Signed-off-by: Vladislav Odintsov <[email protected]> --- v1 -> v2: - Addressed Ales's comment: replaced ip_parse() & ipv6_parse() with ip46_parse(). --- controller/pinctrl.c | 37 ++++++++++++++++--------------------- 1 file changed, 16 insertions(+), 21 deletions(-) diff --git a/controller/pinctrl.c b/controller/pinctrl.c index 6a2c3dc68..0178ac6cc 100644 --- a/controller/pinctrl.c +++ b/controller/pinctrl.c @@ -7307,6 +7307,9 @@ struct svc_monitor { long long int timestamp; bool is_ip6; + struct eth_addr src_mac; + struct in6_addr src_ip; + long long int wait_time; long long int next_send_time; @@ -7501,6 +7504,9 @@ sync_svc_monitors(struct ovsdb_idl_txn *ovnsb_idl_txn, svc_mon->n_success = 0; svc_mon->n_failures = 0; + eth_addr_from_string(sb_svc_mon->src_mac, &svc_mon->src_mac); + ip46_parse(sb_svc_mon->src_ip, &svc_mon->src_ip); + hmap_insert(&svc_monitors_map, &svc_mon->hmap_node, hash); ovs_list_push_back(&svc_monitors, &svc_mon->list_node); changed = true; @@ -8259,19 +8265,14 @@ svc_monitor_send_tcp_health_check__(struct rconn *swconn, struct dp_packet packet; dp_packet_use_stub(&packet, packet_stub, sizeof packet_stub); - struct eth_addr eth_src; - eth_addr_from_string(svc_mon->sb_svc_mon->src_mac, ð_src); if (svc_mon->is_ip6) { - struct in6_addr ip6_src; - ipv6_parse(svc_mon->sb_svc_mon->src_ip, &ip6_src); - pinctrl_compose_ipv6(&packet, eth_src, svc_mon->ea, - &ip6_src, &svc_mon->ip, IPPROTO_TCP, + pinctrl_compose_ipv6(&packet, svc_mon->src_mac, svc_mon->ea, + &svc_mon->src_ip, &svc_mon->ip, IPPROTO_TCP, 63, TCP_HEADER_LEN); } else { - ovs_be32 ip4_src; - ip_parse(svc_mon->sb_svc_mon->src_ip, &ip4_src); - pinctrl_compose_ipv4(&packet, eth_src, svc_mon->ea, - ip4_src, in6_addr_get_mapped_ipv4(&svc_mon->ip), + pinctrl_compose_ipv4(&packet, svc_mon->src_mac, svc_mon->ea, + in6_addr_get_mapped_ipv4(&svc_mon->src_ip), + in6_addr_get_mapped_ipv4(&svc_mon->ip), IPPROTO_TCP, 63, TCP_HEADER_LEN); } @@ -8327,24 +8328,18 @@ svc_monitor_send_udp_health_check(struct rconn *swconn, struct svc_monitor *svc_mon, ovs_be16 udp_src) { - struct eth_addr eth_src; - eth_addr_from_string(svc_mon->sb_svc_mon->src_mac, ð_src); - uint64_t packet_stub[128 / 8]; struct dp_packet packet; dp_packet_use_stub(&packet, packet_stub, sizeof packet_stub); if (svc_mon->is_ip6) { - struct in6_addr ip6_src; - ipv6_parse(svc_mon->sb_svc_mon->src_ip, &ip6_src); - pinctrl_compose_ipv6(&packet, eth_src, svc_mon->ea, - &ip6_src, &svc_mon->ip, IPPROTO_UDP, + pinctrl_compose_ipv6(&packet, svc_mon->src_mac, svc_mon->ea, + &svc_mon->src_ip, &svc_mon->ip, IPPROTO_UDP, 63, UDP_HEADER_LEN + 8); } else { - ovs_be32 ip4_src; - ip_parse(svc_mon->sb_svc_mon->src_ip, &ip4_src); - pinctrl_compose_ipv4(&packet, eth_src, svc_mon->ea, - ip4_src, in6_addr_get_mapped_ipv4(&svc_mon->ip), + pinctrl_compose_ipv4(&packet, svc_mon->src_mac, svc_mon->ea, + in6_addr_get_mapped_ipv4(&svc_mon->src_ip), + in6_addr_get_mapped_ipv4(&svc_mon->ip), IPPROTO_UDP, 63, UDP_HEADER_LEN + 8); } -- 2.44.0 _______________________________________________ dev mailing list [email protected] https://mail.openvswitch.org/mailman/listinfo/ovs-dev
