CVE-2023-52487

En el kernel de Linux, se resolvió la siguiente vulnerabilidad: net/mlx5e: corrigió el manejo de listas de flujos de pares. El cambio citado refactorizó mlx5e_tc_del_fdb_peer_flow() para borrar solo el indicador DUP cuando la lista de flujos de pares quedó vacía. Sin embargo, si algún usuario simultáneo tiene una referencia a un flujo de pares (por ejemplo, la tarea de actualización de la cola de trabajo del vecino está actualizando la entrada de encapsulación principal del flujo de pares simultáneamente), entonces el flujo no se eliminará de la lista de pares y, consecutivamente, se activará el indicador DUP. permanecer configurado. Dado que mlx5e_tc_del_fdb_peers_flow() llama a mlx5e_tc_del_fdb_peer_flow() para cada índice de pares posible, el algoritmo intentará eliminar el flujo de las instancias de eswitch con las que nunca ha emparejado, lo que provocará una desreferencia del puntero NULL al intentar eliminar el encabezado de la lista de pares de flujo de peer_index que nunca se inicializó. o una advertencia si la configuración de depuración de la lista está habilitada [0]. Solucione el problema eliminando siempre el flujo de pares de la lista, incluso cuando no publique la última referencia al mismo. [0]: [3102.985806] ------------[ cortar aquí ]------------ [ 3102.986223] list_del corrupción, ffff888139110698->el siguiente es NULL [ 3102.986757] ADVERTENCIA: CPU: 2 PID: 22109 en lib/list_debug.c:53 __list_del_entry_valid_or_report+0x4f/0xc0 [3102.987561] Módulos vinculados en: act_ct nf_flow_table bonding act_tunnel_key act_mirred act_skbedit vxlan cls_matchall nfnetlink_cttimeout act_gact cl s_flower sch_ingress mlx5_vdpa vringh vhost_iotlb vdpa openvswitch nsh xt_MASQUERADE nf_conntrack_netlink nfnetlink iptable_nat xt_addrtype xt_conntrack nf_nat br_netfilter rpcsec_gss_krb5 auth_rpcg ss oid_registry superposición rpcrdma rdma_ucm ib_iser libiscsi scsi_transport_iscsi ib_umad rdma_cm ib_ipoib iw_cm ib_cm mlx5_ib ib_uverbs ib_core mlx5 _core [última descarga: unión] [3102.991113] CPU: 2 PID: 22109 Comm: revalidator28 No contaminado 6.6.0-rc6+ #3 [ 3102.991695] Nombre del hardware: PC estándar QEMU (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 01/04/2014 [ 3102.992605] RIP: 0010:__list_del_entry_valid_or_report+0x4 f/0xc0 [ 3102.993122] Código: 39 c2 74 56 48 8b 32 48 39 fe 75 62 48 8b 51 08 48 39 f2 75 73 b8 01 00 00 00 c3 48 89 fe 48 c7 c7 48 fd 0a 82 e8 41 0b anuncio ff <0f> 0b 31 c0 c3 48 89 fe 48 c7 c7 70 fd 0a 82 e8 2d 0b ad ff 0f 0b [ 3102.994615] RSP: 0018:ffff8881383e7710 EFLAGS: 00010286 [ 3102.995078] RAX: 000 0000000000000 RBX: 0000000000000002 RCX: 0000000000000000 [ 3102.995670] RDX: 0000000000000001 RSI: ffff88885f89b640 RDI: ffff88885f89b640 [ 3102.997188] Flujo DEL 00000000be367878 en el puerto 0 [ 3102.998594] RBP: dead000000000122 R08: 00000000000000000 R 09: c0000000ffffdfff [ 3102.999604] R10: 0000000000000008 R11: ffff8881383e7598 R12: muerto000000000100 [ 3103.000198] R13: 0000000000000002 R14 :ffff888139110000 R15: ffff888101901240 [ 3103.000790] FS: 00007f424cde4700(0000) GS:ffff88885f880000(0000) knlGS:00000000000000000 [ 3103.001486] CS: 0010 DS: 000 0 ES: 0000 CR0: 0000000080050033 [ 3103.001986] CR2: 00007fd42e8dcb70 CR3: 000000011e68a003 CR4: 0000000000370ea0 [ 3103.002596] DR0 : 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 3103.003190] DR3: 0000000000000000 DR6: 00000000ffe0ff0 DR7: 00000000000 00400 [ 3103.003787] Seguimiento de llamadas: [ 3103.004055] [ 3103.004297] ? __advertir+0x7d/0x130 [ 3103.004623] ? __list_del_entry_valid_or_report+0x4f/0xc0 [3103.005094] ? report_bug+0xf1/0x1c0 [3103.005439]? console_unlock+0x4a/0xd0 [3103.005806]? handle_bug+0x3f/0x70 [3103.006149]? exc_invalid_op+0x13/0x60 [3103.006531]? asm_exc_invalid_op+0x16/0x20 [3103.007430]? __list_del_entry_valid_or_report+0x4f/0xc0 [3103.007910] mlx5e_tc_del_fdb_peers_flow+0xcf/0x240 [mlx5_core] [3103.008463] mlx5e_tc_del_flow+0x46/0x270 truncado

In the Linux kernel, the following vulnerability has been resolved: net/mlx5e: Fix peer flow lists handling The cited change refactored mlx5e_tc_del_fdb_peer_flow() to only clear DUP flag when list of peer flows has become empty. However, if any concurrent user holds a reference to a peer flow (for example, the neighbor update workqueue task is updating peer flow's parent encap entry concurrently), then the flow will not be removed from the peer list and, consecutively, DUP flag will remain set. Since mlx5e_tc_del_fdb_peers_flow() calls mlx5e_tc_del_fdb_peer_flow() for every possible peer index the algorithm will try to remove the flow from eswitch instances that it has never peered with causing either NULL pointer dereference when trying to remove the flow peer list head of peer_index that was never initialized or a warning if the list debug config is enabled[0]. Fix the issue by always removing the peer flow from the list even when not releasing the last reference to it. [0]: [ 3102.985806] ------------[ cut here ]------------ [ 3102.986223] list_del corruption, ffff888139110698->next is NULL [ 3102.986757] WARNING: CPU: 2 PID: 22109 at lib/list_debug.c:53 __list_del_entry_valid_or_report+0x4f/0xc0 [ 3102.987561] Modules linked in: act_ct nf_flow_table bonding act_tunnel_key act_mirred act_skbedit vxlan cls_matchall nfnetlink_cttimeout act_gact cls_flower sch_ingress mlx5_vdpa vringh vhost_iotlb vdpa openvswitch nsh xt_MASQUERADE nf_conntrack_netlink nfnetlink iptable_nat xt_addrtype xt_conntrack nf_nat br_netfilter rpcsec_gss_krb5 auth_rpcg ss oid_registry overlay rpcrdma rdma_ucm ib_iser libiscsi scsi_transport_iscsi ib_umad rdma_cm ib_ipoib iw_cm ib_cm mlx5_ib ib_uverbs ib_core mlx5_core [last unloaded: bonding] [ 3102.991113] CPU: 2 PID: 22109 Comm: revalidator28 Not tainted 6.6.0-rc6+ #3 [ 3102.991695] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014 [ 3102.992605] RIP: 0010:__list_del_entry_valid_or_report+0x4f/0xc0 [ 3102.993122] Code: 39 c2 74 56 48 8b 32 48 39 fe 75 62 48 8b 51 08 48 39 f2 75 73 b8 01 00 00 00 c3 48 89 fe 48 c7 c7 48 fd 0a 82 e8 41 0b ad ff <0f> 0b 31 c0 c3 48 89 fe 48 c7 c7 70 fd 0a 82 e8 2d 0b ad ff 0f 0b [ 3102.994615] RSP: 0018:ffff8881383e7710 EFLAGS: 00010286 [ 3102.995078] RAX: 0000000000000000 RBX: 0000000000000002 RCX: 0000000000000000 [ 3102.995670] RDX: 0000000000000001 RSI: ffff88885f89b640 RDI: ffff88885f89b640 [ 3102.997188] DEL flow 00000000be367878 on port 0 [ 3102.998594] RBP: dead000000000122 R08: 0000000000000000 R09: c0000000ffffdfff [ 3102.999604] R10: 0000000000000008 R11: ffff8881383e7598 R12: dead000000000100 [ 3103.000198] R13: 0000000000000002 R14: ffff888139110000 R15: ffff888101901240 [ 3103.000790] FS: 00007f424cde4700(0000) GS:ffff88885f880000(0000) knlGS:0000000000000000 [ 3103.001486] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 3103.001986] CR2: 00007fd42e8dcb70 CR3: 000000011e68a003 CR4: 0000000000370ea0 [ 3103.002596] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 3103.003190] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 3103.003787] Call Trace: [ 3103.004055] <TASK> [ 3103.004297] ? __warn+0x7d/0x130 [ 3103.004623] ? __list_del_entry_valid_or_report+0x4f/0xc0 [ 3103.005094] ? report_bug+0xf1/0x1c0 [ 3103.005439] ? console_unlock+0x4a/0xd0 [ 3103.005806] ? handle_bug+0x3f/0x70 [ 3103.006149] ? exc_invalid_op+0x13/0x60 [ 3103.006531] ? asm_exc_invalid_op+0x16/0x20 [ 3103.007430] ? __list_del_entry_valid_or_report+0x4f/0xc0 [ 3103.007910] mlx5e_tc_del_fdb_peers_flow+0xcf/0x240 [mlx5_core] [ 3103.008463] mlx5e_tc_del_flow+0x46/0x270 [mlx5_core] [ 3103.008944] mlx5e_flow_put+0x26/0x50 [mlx5_core] [ 3103.009401] mlx5e_delete_flower+0x25f/0x380 [mlx5_core] [ 3103.009901] tc_setup_cb_destroy+0xab/0x180 [ 3103.010292] fl_hw_destroy_filter+0x99/0xc0 [cls_flower] [ 3103.010779] __fl_delete+0x2d4/0x2f0 [cls_flower] [ 3103.0 ---truncated---