Vulnerabilidad en kernel de Linux (CVE-2024-49947)

En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: net: prueba de que csum_start no sea demasiado pequeño en virtio_net_hdr_to_skb() syzbot pudo activar esta advertencia [1], después de inyectar un paquete malicioso a través de af_packet, configurando skb->csum_start y, por lo tanto, el encabezado de transporte con un valor incorrecto. Al menos podemos asegurarnos de que el encabezado de transporte esté después del final del encabezado de red (con un tamaño mínimo estimado). [1] [ 67.873027] longitud skb=4096 espacio libre=16 longitud libre=14 espacio libre=0 mac=(-1,-1) longitud_mac=0 red=(16,-6) trans=10 shinfo(txflags=0 nr_frags=1 gso(tamaño=0 tipo=0 segmentos=0)) suma_c(0xa inicio=10 desplazamiento=0 suma_ip=3 software_completo=0 válido=0 nivel=0) hash(0x0 software=0 l4=0) proto=0x0800 tipo_paquete=0 iif=0 prioridad=0x0 marca=0x0 asignar_cpu=10 vlan_all=0x0 encapsulación=0 interno(proto=0x0000, mac=0, red=0, trans=0) [ 67.877172] nombre_de_desarrollo=veth0_vlan hazaña=0x000061164fdd09e9 [ 67.877764] familia sk=17 tipo=3 proto=0 [ 67.878279] skb lineal: 00000000: 00 00 10 00 00 00 00 00 0f 00 00 00 08 00 [ 67.879128] fragmento skb: 00000000: 0e 00 07 00 00 00 28 00 08 80 1c 00 04 00 00 02 [ 67.879877] fragmento skb: 00000010: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 67.880647] skb frag: 00000020: 00 00 02 00 00 00 08 00 1b 00 00 00 00 00 00 00 [ 67.881156] skb frag: 0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [67.881753] skb frag: 00000040: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [67.882173] fragmento de skb: 00000050: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [67.882790] fragmento de skb: 00000060: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 67.883171] skb frag: 00000070: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 67.883733] fragmento: 00000080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 67.884206] fragmento skb: 00000090: 00 00 00 00 00 00 00 00 00 00 69 70 76 6c 61 6e [ 67.884704] fragmento skb: 000000a0: 31 00 00 00 00 00 00 00 00 00 2b 00 00 00 00 00 [ 67.885139] fragmento skb: 000000b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 67.885677] fragmento de skb: 000000c0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 67.886042] fragmento de skb: 000000d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 67.886408] fragmento de skb: 000000e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 67.887020] fragmento skb: 000000f0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 67.887384] fragmento skb: 00000100: 00 00 [ 67.887878] ------------[ cortar aquí ]------------ [ 67.887908] desplazamiento (-6) >= skb_headlen() (14) [ 67.888445] ADVERTENCIA: CPU: 10 PID: 2088 en net/core/dev.c:3332 skb_checksum_help (net/core/dev.c:3332 (discriminador 2)) [ 67.889353] Módulos vinculados en: macsec macvtap macvlan hsr wireguard curve25519_x86_64 libcurve25519_generic libchacha20poly1305 chacha_x86_64 libchacha poly1305_x86_64 puente ficticio sr_mod cdrom evdev pcspkr i2c_piix4 9pnet_virtio 9p 9pnet netfs [ 67.890111] CPU: 10 UID: 0 PID: 2088 Comm: b363492833 No contaminado 6.11.0-virtme #1011 [ 67.890183] Nombre del hardware: QEMU PC estándar (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 01/04/2014 [ 67.890309] RIP: 0010:skb_checksum_help (net/core/dev.c:3332 (discriminador 2)) [ 67.891043] Seguimiento de llamadas: [ 67.891173] [ 67.891274] ? __warn (kernel/panic.c:741) [ 67.891320] ? skb_checksum_help (net/core/dev.c:3332 (discriminador 2)) [ 67.891333] ? report_bug (lib/bug.c:180 lib/bug.c:219) [ 67.891348] ? handle_bug (arch/x86/kernel/traps.c:239) [ 67.891363] ? exc_invalid_op (arch/x86/kernel/traps.c:260 (discriminador 1)) [ ---truncado---