CVE-2024-26893

En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: firmware: arm_scmi: Corrección de doble liberación en la ruta de limpieza del transporte SMC Cuando el código SCMI genérico destruye un canal, llama a la función de devolución de llamada chan_free, definida por cada transporte. Dado que varios protocolos pueden compartir el mismo miembro transport_info, es posible que chan_free() desee limpiar el mismo miembro varias veces dentro de la implementación de transporte SCMI determinada. En este caso se trata de transporte SMC. Esto dará lugar a una desreferencia del puntero NULL la segunda vez: | scmi_protocol scmi_dev.1: Canal TX en modo de sondeo habilitado - prot_id:16 | firmware arm-scmi: scmi: Notificaciones SCMI: núcleo habilitado. | firmware arm-scmi: scmi: no se puede comunicar con SCMI | No se puede manejar la desreferencia del puntero NULL del kernel en la dirección virtual 0000000000000000 | Información de cancelación de memoria: | ESR = 0x0000000096000004 | EC = 0x25: DABT (EL actual), IL = 32 bits | CONJUNTO = 0, FnV = 0 | EA = 0, S1PTW = 0 | FSC = 0x04: error de traducción de nivel 0 | Información de cancelación de datos: | ISV = 0, ISS = 0x00000004, ISS2 = 0x00000000 | CM = 0, WnR = 0, TnD = 0, Acceso a etiquetas = 0 | GCS = 0, Superposición = 0, DirtyBit = 0, Xs = 0 | pgtable de usuario: páginas de 4k, VA de 48 bits, pgdp=0000000881ef8000 | [0000000000000000] pgd=0000000000000000, p4d=0000000000000000 | Error interno: Ups: 0000000096000004 [#1] SMP ANTICIPADO | Módulos enlazados en: | CPU: 4 PID: 1 Comunicaciones: swapper/0 No contaminado 6.7.0-rc2-00124-g455ef3d016c9-dirty #793 | Nombre del hardware: FVP Base RevC (DT) | pstate: 61400009 (nZCv daif +PAN -UAO -TCO +DIT -SSBS BTYPE=--) | ordenador personal: smc_chan_free+0x3c/0x6c | lr: smc_chan_free+0x3c/0x6c | Rastreo de llamadas: | smc_chan_free+0x3c/0x6c | idr_for_each+0x68/0xf8 | scmi_cleanup_channels.isra.0+0x2c/0x58 | scmi_probe+0x434/0x734 | sonda_plataforma+0x68/0xd8 | realmente_probe+0x110/0x27c | __driver_probe_device+0x78/0x12c | dispositivo_sonda_controlador+0x3c/0x118 | __driver_attach+0x74/0x128 | bus_for_each_dev+0x78/0xe0 | driver_attach+0x24/0x30 | bus_add_driver+0xe4/0x1e8 | registro_controlador+0x60/0x128 | __platform_driver_register+0x28/0x34 | scmi_driver_init+0x84/0xc0 | do_one_initcall+0x78/0x33c | kernel_init_freeable+0x2b8/0x51c | kernel_init+0x24/0x130 | ret_from_fork+0x10/0x20 | Código: f0004701 910a0021 aa1403e5 97b91c70 (b9400280) | ---[ end trace 0000000000000000 ]--- Simplemente verifique que el puntero de estructura sea NULL antes de intentar acceder a sus miembros, para evitar esta situación. Esto se encontró cuando un transporte realmente no funciona (por ejemplo, sin servicio SMC), las rutinas de la sonda intentan limpiarse y provocan un bloqueo.

In the Linux kernel, the following vulnerability has been resolved: firmware: arm_scmi: Fix double free in SMC transport cleanup path When the generic SCMI code tears down a channel, it calls the chan_free callback function, defined by each transport. Since multiple protocols might share the same transport_info member, chan_free() might want to clean up the same member multiple times within the given SCMI transport implementation. In this case, it is SMC transport. This will lead to a NULL pointer dereference at the second time: | scmi_protocol scmi_dev.1: Enabled polling mode TX channel - prot_id:16 | arm-scmi firmware:scmi: SCMI Notifications - Core Enabled. | arm-scmi firmware:scmi: unable to communicate with SCMI | Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000 | Mem abort info: | ESR = 0x0000000096000004 | EC = 0x25: DABT (current EL), IL = 32 bits | SET = 0, FnV = 0 | EA = 0, S1PTW = 0 | FSC = 0x04: level 0 translation fault | Data abort info: | ISV = 0, ISS = 0x00000004, ISS2 = 0x00000000 | CM = 0, WnR = 0, TnD = 0, TagAccess = 0 | GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0 | user pgtable: 4k pages, 48-bit VAs, pgdp=0000000881ef8000 | [0000000000000000] pgd=0000000000000000, p4d=0000000000000000 | Internal error: Oops: 0000000096000004 [#1] PREEMPT SMP | Modules linked in: | CPU: 4 PID: 1 Comm: swapper/0 Not tainted 6.7.0-rc2-00124-g455ef3d016c9-dirty #793 | Hardware name: FVP Base RevC (DT) | pstate: 61400009 (nZCv daif +PAN -UAO -TCO +DIT -SSBS BTYPE=--) | pc : smc_chan_free+0x3c/0x6c | lr : smc_chan_free+0x3c/0x6c | Call trace: | smc_chan_free+0x3c/0x6c | idr_for_each+0x68/0xf8 | scmi_cleanup_channels.isra.0+0x2c/0x58 | scmi_probe+0x434/0x734 | platform_probe+0x68/0xd8 | really_probe+0x110/0x27c | __driver_probe_device+0x78/0x12c | driver_probe_device+0x3c/0x118 | __driver_attach+0x74/0x128 | bus_for_each_dev+0x78/0xe0 | driver_attach+0x24/0x30 | bus_add_driver+0xe4/0x1e8 | driver_register+0x60/0x128 | __platform_driver_register+0x28/0x34 | scmi_driver_init+0x84/0xc0 | do_one_initcall+0x78/0x33c | kernel_init_freeable+0x2b8/0x51c | kernel_init+0x24/0x130 | ret_from_fork+0x10/0x20 | Code: f0004701 910a0021 aa1403e5 97b91c70 (b9400280) | ---[ end trace 0000000000000000 ]--- Simply check for the struct pointer being NULL before trying to access its members, to avoid this situation. This was found when a transport doesn't really work (for instance no SMC service), the probe routines then tries to clean up, and triggers a crash.

Ziming Zhang discovered that the DRM driver for VMware Virtual GPU did not properly handle certain error conditions, leading to a NULL pointer dereference. A local attacker could possibly trigger this vulnerability to cause a denial of service. Zheng Wang discovered that the Broadcom FullMAC WLAN driver in the Linux kernel contained a race condition during device removal, leading to a use- after-free vulnerability. A physically proximate attacker could possibly use this to cause a denial of service.