CVE-2024-38538

En el kernel de Linux, se resolvió la siguiente vulnerabilidad: net: bridge: xmit: asegúrese de tener al menos el encabezado eth len bytes syzbot desencadenó un error de valor uninit[1] en la ruta xmit del dispositivo puente al enviar un mensaje corto (menos de ETH_HLEN bytes) skb. Para solucionarlo, compruebe si realmente podemos retirar esa cantidad en lugar de suponerla. Probado con dropwatch: soltar en: br_dev_xmit+0xb93/0x12d0 [puente] (0xffffffffc06739b3) origen: marca de tiempo del software: lunes 13 de mayo 11:31:53 2024 778214037 protocolo nsec: 0x88a8 longitud: 2 longitud original: 2 motivo de caída: PKT_TOO_SMALL [1 ] ERROR: KMSAN: valor uninit en br_dev_xmit+0x61d/0x1cb0 net/bridge/br_device.c:65 br_dev_xmit+0x61d/0x1cb0 net/bridge/br_device.c:65 __netdev_start_xmit include/linux/netdevice.h:4903 [en línea] netdev_start_xmit include/linux/netdevice.h:4917 [en línea] xmit_one net/core/dev.c:3531 [en línea] dev_hard_start_xmit+0x247/0xa20 net/core/dev.c:3547 __dev_queue_xmit+0x34db/0x5350 net/core/dev .c:4341 dev_queue_xmit include/linux/netdevice.h:3091 [en línea] __bpf_tx_skb net/core/filter.c:2136 [en línea] __bpf_redirect_common net/core/filter.c:2180 [en línea] __bpf_redirect+0x14a6/0x1620 net/ Core/Filter.C: 2187 ____BPF_CLONE_REDIRECT NET/CORE/FILTRO.C: 2460 [Inline] BPF_CLONE_REDIRECT+0x328/0x470 NET/Core/Filter.c: 2432 ___ BPF_PROG_RUN+0X13FE/0XE0F0 KERNEL/BPF/BPF/CORE. 0xb5/0xe0 kernel/bpf/core.c:2238 bpf_dispatcher_nop_func include/linux/bpf.h:1234 [en línea] __bpf_prog_run include/linux/filter.h:657 [en línea] bpf_prog_run include/linux/filter.h:664 [en línea ] bpf_test_run+0x499/0xc30 net/bpf/test_run.c:425 bpf_prog_test_run_skb+0x14ea/0x1f20 net/bpf/test_run.c:1058 bpf_prog_test_run+0x6b7/0xad0 kernel/bpf/syscall.c:4269 pf+0x6aa/0xd90 núcleo/ bpf/syscall.c:5678 __do_sys_bpf kernel/bpf/syscall.c:5767 [en línea] __se_sys_bpf kernel/bpf/syscall.c:5765 [en línea] __x64_sys_bpf+0xa0/0xe0 kernel/bpf/syscall.c:5765 ys_call+0x96b /0x3b50 arch/x86/include/generated/asm/syscalls_64.h:322 do_syscall_x64 arch/x86/entry/common.c:52 [en línea] do_syscall_64+0xcf/0x1e0 arch/x86/entry/common.c:83 Entry_SYSCALL_64_after_hwframe+ 0x77/0x7f

In the Linux kernel, the following vulnerability has been resolved: net: bridge: xmit: make sure we have at least eth header len bytes syzbot triggered an uninit value[1] error in bridge device's xmit path by sending a short (less than ETH_HLEN bytes) skb. To fix it check if we can actually pull that amount instead of assuming. Tested with dropwatch: drop at: br_dev_xmit+0xb93/0x12d0 [bridge] (0xffffffffc06739b3) origin: software timestamp: Mon May 13 11:31:53 2024 778214037 nsec protocol: 0x88a8 length: 2 original length: 2 drop reason: PKT_TOO_SMALL [1] BUG: KMSAN: uninit-value in br_dev_xmit+0x61d/0x1cb0 net/bridge/br_device.c:65 br_dev_xmit+0x61d/0x1cb0 net/bridge/br_device.c:65 __netdev_start_xmit include/linux/netdevice.h:4903 [inline] netdev_start_xmit include/linux/netdevice.h:4917 [inline] xmit_one net/core/dev.c:3531 [inline] dev_hard_start_xmit+0x247/0xa20 net/core/dev.c:3547 __dev_queue_xmit+0x34db/0x5350 net/core/dev.c:4341 dev_queue_xmit include/linux/netdevice.h:3091 [inline] __bpf_tx_skb net/core/filter.c:2136 [inline] __bpf_redirect_common net/core/filter.c:2180 [inline] __bpf_redirect+0x14a6/0x1620 net/core/filter.c:2187 ____bpf_clone_redirect net/core/filter.c:2460 [inline] bpf_clone_redirect+0x328/0x470 net/core/filter.c:2432 ___bpf_prog_run+0x13fe/0xe0f0 kernel/bpf/core.c:1997 __bpf_prog_run512+0xb5/0xe0 kernel/bpf/core.c:2238 bpf_dispatcher_nop_func include/linux/bpf.h:1234 [inline] __bpf_prog_run include/linux/filter.h:657 [inline] bpf_prog_run include/linux/filter.h:664 [inline] bpf_test_run+0x499/0xc30 net/bpf/test_run.c:425 bpf_prog_test_run_skb+0x14ea/0x1f20 net/bpf/test_run.c:1058 bpf_prog_test_run+0x6b7/0xad0 kernel/bpf/syscall.c:4269 __sys_bpf+0x6aa/0xd90 kernel/bpf/syscall.c:5678 __do_sys_bpf kernel/bpf/syscall.c:5767 [inline] __se_sys_bpf kernel/bpf/syscall.c:5765 [inline] __x64_sys_bpf+0xa0/0xe0 kernel/bpf/syscall.c:5765 x64_sys_call+0x96b/0x3b50 arch/x86/include/generated/asm/syscalls_64.h:322 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcf/0x1e0 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Benedict Schlüter, Supraja Sridhara, Andrin Bertschi, and Shweta Shinde discovered that an untrusted hypervisor could inject malicious #VC interrupts and compromise the security guarantees of AMD SEV-SNP. This flaw is known as WeSee. A local attacker in control of the hypervisor could use this to expose sensitive information or possibly execute arbitrary code in the trusted execution environment. Several security issues were discovered in the Linux kernel. An attacker could possibly use these to compromise the system.