Vulnerabilidad en kernel de Linux (CVE-2024-50037)

En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: drm/fbdev-dma: Solo limpiar la E/S diferida si es necesario el commit 5a498d4d06d6 ("drm/fbdev-dma: Solo instalar la E/S diferida si es necesario") inicializa la E/S diferida solo si se usa. Sin embargo, drm_fbdev_dma_fb_destroy() llama a fb_deferred_io_cleanup() incondicionalmente con struct fb_info.fbdefio == NULL. KASAN con el controlador de pantalla de silicio de Apple fuera del árbol publica la siguiente advertencia de __flush_work() de una estructura aleatoria work_struct en lugar de las derefs de puntero NULL esperadas. [ 22.053799] ------------[ cortar aquí ]------------ [ 22.054832] ADVERTENCIA: CPU: 2 PID: 1 en kernel/workqueue.c:4177 __flush_work+0x4d8/0x580 [ 22.056597] Módulos vinculados en: uhid bnep uinput nls_ascii ip6_tables ip_tables i2c_dev loop fuse dm_multipath nfnetlink zram hid_magicmouse btrfs xor xor_neon brcmfmac_wcc raid6_pq hci_bcm4377 bluetooth brcmfmac hid_apple brcmutil nvmem_spmi_mfd simple_mfd_spmi dockchannel_hid cfg80211 joydev regmap_spmi nvme_apple ecdh_generic ecc macsmc_hid rfkill dwc3 appledrm snd_soc_macaudio macsmc_power nvme_core apple_isp phy_apple_atc apple_sart apple_rtkit_helper apple_dockchannel tps6598x macsmc_hwmon snd_soc_cs42l84 videobuf2_v4l2 spmi_apple_controller nvmem_apple_efuses videobuf2_dma_sg apple_z2 videobuf2_memops spi_nor panel_summit videobuf2_common asahi videodev pwm_apple apple_dcp snd_soc_apple_mca apple_admac spi_apple clk_apple_nco i2c_pasemi_platform snd_pcm_dmaengine mc i2c_pasemi_core mux_core ofpart adpdrm drm_dma_helper apple_dart apple_soc_cpufreq leds_pwm phram [ 22.073768] CPU: 2 UID: 0 PID: 1 Comm: systemd-shutdow No contaminado 6.11.2-asahi+ #asahi-dev [ 22.075612] Nombre del hardware: Apple MacBook Pro (13 pulgadas, M2, 2022) (DT) [ 22.077032] pstate: 01400005 (nzcv daif +PAN -UAO -TCO +DIT -SSBS BTYPE=--) [ 22.078567] pc : __flush_work+0x4d8/0x580 [ 22.079471] lr : __flush_work+0x54/0x580 [ [22.080345] sp: ffffc000836ef820 [22.081089] x29: ffffc000836ef880 x28: 0000000000000000 x27: ffff80002ddb7128 [22.082678] x26: dfffc0000000000 x25: 1ffff000096f0c57 x24: ffffc00082d3e358 [22.084263] x23: ffff80004b7862b8 x22: dfffc0000000000 x21: ffff80005aa1d470 [22.085855] x20: ffff80004b786000 x19: ffff80004b7862a0 x18: 0000000000000000 [ 22.087439] x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000005 [ 22.089030] x14: 1ffff800106ddf0a x13: 0000000000000000 x12: 0000000000000000 [ 22.090618] x11: ffffb800106ddf0f x10: dfffc00000000000 x9: 1ffff800106ddf0e [22.092206] x8: 0000000000000000 x7: aaaaaaaaaaaaaaaa x6: 0000000000000001 [22.093790] x5: 00836ef728 x4: 0000000000000000 x3: 0000000000000020 [22.095368] x2: 00000000000000008 x1: 00000000000000aa x0: 00000000000000000 [ 22.096955] Rastreo de llamadas: [ 22.097505] __flush_work+0x4d8/0x580 [ 22.098330] flush_delayed_work+0x80/0xb8 [ 22.099231] fb_deferred_io_cleanup+0x3c/0x130 [ 22.100217] drm_fbdev_dma_fb_destroy+0x6c/0xe0 [drm_dma_helper] [ 22.101559] anular registro de búfer de fotogramas+0x210/0x2f0 [ 22.102575] drm_fb_helper_anular registro de información+0x48/0x60 [ 22.103683] drm_fbdev_dma_client_unregister+0x4c/0x80 [drm_dma_helper] [ 22.105147] drm_client_dev_unregister+0x1cc/0x230 [ 22.106217] drm_dev_unregister+0x58/0x570 [ 22.107125] apple_drm_unbind+0x50/0x98 [appledrm] [ 22.108199] component_del+0x1f8/0x3a8 [ 22.109042] dcp_platform_shutdown+0x24/0x38 [apple_dcp] [ 22.110357] platform_shutdown+0x70/0x90 [ 22.111219] apagado_dispositivo+0x368/0x4d8 [ 22.112095] reinicio_kernel+0x6c/0x1d0 [ 22.112946] reinicio_del_sistema_arm64+0x1c8/0x328 [ 22.113868] invocar_llamada_al_sistema+0x78/0x1a8 [ 22.114703] hacer_el0_svc+0x124/0x1a0 [ 22.115498] el0_svc+0x3c/0xe0 [ 22.116181] controlador_sincronización_el0t_64+0x70/0xc0 [ 22.117110] el0t_64_sync+0x190/0x198 [ 22.117931] ---[ fin de seguimiento 0000000000000000 ]---