Vulnerabilidad en kernel de Linux (CVE-2024-26633)

En el kernel de Linux, se resolvió la siguiente vulnerabilidad: ip6_tunnel: corrige el manejo de NEXTHDR_FRAGMENT en ip6_tnl_parse_tlv_enc_lim() syzbot señaló [1] que el manejo de NEXTHDR_FRAGMENT no funciona. La lectura de frag_off solo se puede realizar si extraemos suficientes bytes para skb->head. Actualmente podríamos acceder a basura. [1] ERROR: KMSAN: valor uninit en ip6_tnl_parse_tlv_enc_lim+0x94f/0xbb0 ip6_tnl_parse_tlv_enc_lim+0x94f/0xbb0 ipxip6_tnl_xmit net/ipv6/ip6_tunnel.c:1326 [en línea] ip6_tnl_start_xmit+0x ab2/0x1a70 net/ipv6/ip6_tunnel.c:1432 __netdev_start_xmit incluye /linux/netdevice.h:4940 [en línea] netdev_start_xmit include/linux/netdevice.h:4954 [en línea] xmit_one net/core/dev.c:3548 [en línea] dev_hard_start_xmit+0x247/0xa10 net/core/dev.c: 3564 __dev_queue_xmit+0x33b8/0x5130 net/core/dev.c:4349 dev_queue_xmit include/linux/netdevice.h:3134 [en línea] neigh_connected_output+0x569/0x660 net/core/neighbour.c:1592 neigh_output include/net/neighbour.h :542 [en línea] ip6_finish_output2+0x23a9/0x2b30 net/ipv6/ip6_output.c:137 ip6_finish_output+0x855/0x12b0 net/ipv6/ip6_output.c:222 NF_HOOK_COND include/linux/netfilter.h:303 [en línea] ip6_output+0x3 23/ 0x610 net/ipv6/ip6_output.c:243 dst_output include/net/dst.h:451 [en línea] ip6_local_out+0xe9/0x140 net/ipv6/output_core.c:155 ip6_send_skb net/ipv6/ip6_output.c:1952 [en línea] ip6_push_pending_frames+0x1f9/0x560 net/ipv6/ip6_output.c:1972 rawv6_push_pending_frames+0xbe8/0xdf0 net/ipv6/raw.c:582 rawv6_sendmsg+0x2b66/0x2e70 net/ipv6/raw.c:920 inet_sendmsg+0 x105/0x190 neto/ipv4 /af_inet.c:847 sock_sendmsg_nosec net/socket.c:730 [en línea] __sock_sendmsg net/socket.c:745 [en línea] ____sys_sendmsg+0x9c2/0xd60 net/socket.c:2584 ___sys_sendmsg+0x28d/0x3c0 net/socket.c :2638 __sys_sendmsg net/socket.c:2667 [en línea] __do_sys_sendmsg net/socket.c:2676 [en línea] __se_sys_sendmsg net/socket.c:2674 [en línea] __x64_sys_sendmsg+0x307/0x490 net/socket.c:267 4 do_syscall_x64 arco/ x86/entry/common.c:52 [en línea] do_syscall_64+0x44/0x110 arch/x86/entry/common.c:83 Entry_SYSCALL_64_after_hwframe+0x63/0x6b Uninit se creó en: slab_post_alloc_hook+0x129/0xa70 mm/slab.h:768 slab_alloc_node mm/slub.c:3478 [en línea] __kmem_cache_alloc_node+0x5c9/0x970 mm/slub.c:3517 __do_kmalloc_node mm/slab_common.c:1006 [en línea] __kmalloc_node_track_caller+0x118/0x3c0 mm/slab_common.c :1027 kmalloc_reserve+0x249/ 0x4a0 net/core/skbuff.c:582 pskb_expand_head+0x226/0x1a00 net/core/skbuff.c:2098 __pskb_pull_tail+0x13b/0x2310 net/core/skbuff.c:2655 pskb_may_pull_reason include/linux/skbuff.h:2673 [en línea ] pskb_may_pull include/linux/skbuff.h:2681 [en línea] ip6_tnl_parse_tlv_enc_lim+0x901/0xbb0 net/ipv6/ip6_tunnel.c:408 ipxip6_tnl_xmit net/ipv6/ip6_tunnel.c:1326 [en línea] ip6_tnl_start_xmit+0xab 2/0x1a70 neto/ipv6/ ip6_tunnel.c:1432 __netdev_start_xmit include/linux/netdevice.h:4940 [en línea] netdev_start_xmit include/linux/netdevice.h:4954 [en línea] xmit_one net/core/dev.c:3548 [en línea] dev_hard_start_xmit+0x247/0xa10 net /core/dev.c:3564 __dev_queue_xmit+0x33b8/0x5130 net/core/dev.c:4349 dev_queue_xmit include/linux/netdevice.h:3134 [en línea] neigh_connected_output+0x569/0x660 net/core/neighbour.c:1592 neigh_output include/net/neighbour.h:542 [en línea] ip6_finish_output2+0x23a9/0x2b30 net/ipv6/ip6_output.c:137 ip6_finish_output+0x855/0x12b0 net/ipv6/ip6_output.c:222 NF_HOOK_COND include/linux/netfilter.h:303 [en línea] ip6_output+0x323/0x610 net/ipv6/ip6_output.c:243 dst_output include/net/dst.h:451 [en línea] ip6_local_out+0xe9/0x140 net/ipv6/output_core.c:155 ip6_send_skb net/ipv6/ip6_output .c:1952 [en línea] ip6_push_pending_frames+0x1f9/0x560 net/ipv6/ip6_output.c:1972 rawv6_push_pending_frames+0xbe8/0xdf0 net/ipv6/raw.c:582 rawv6_sendmsg+0x2b66/0x2e70 net/ipv6/raw.c:9 20 inet_sendmsg +0x105/0x190 net/ipv4/af_inet.c:847 sock_sendmsg_nosec net/socket.c:730 [en línea] __sock_sendmsg net/socket.c:745 [en línea]---truncado---