CVE-2024-50037

Published Oct 21, 2024

Last updated 2 years ago

Overview

Description
In the Linux kernel, the following vulnerability has been resolved: drm/fbdev-dma: Only cleanup deferred I/O if necessary Commit 5a498d4d06d6 ("drm/fbdev-dma: Only install deferred I/O if necessary") initializes deferred I/O only if it is used. drm_fbdev_dma_fb_destroy() however calls fb_deferred_io_cleanup() unconditionally with struct fb_info.fbdefio == NULL. KASAN with the out-of-tree Apple silicon display driver posts following warning from __flush_work() of a random struct work_struct instead of the expected NULL pointer derefs. [ 22.053799] ------------[ cut here ]------------ [ 22.054832] WARNING: CPU: 2 PID: 1 at kernel/workqueue.c:4177 __flush_work+0x4d8/0x580 [ 22.056597] Modules linked in: 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 Not tainted 6.11.2-asahi+ #asahi-dev [ 22.075612] Hardware name: Apple MacBook Pro (13-inch, 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: dfffc00000000000 x25: 1ffff000096f0c57 x24: ffffc00082d3e358 [ 22.084263] x23: ffff80004b7862b8 x22: dfffc00000000000 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 : ffffc000836ef728 x4 : 0000000000000000 x3 : 0000000000000020 [ 22.095368] x2 : 0000000000000008 x1 : 00000000000000aa x0 : 0000000000000000 [ 22.096955] Call trace: [ 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] unregister_framebuffer+0x210/0x2f0 [ 22.102575] drm_fb_helper_unregister_info+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] device_shutdown+0x368/0x4d8 [ 22.112095] kernel_restart+0x6c/0x1d0 [ 22.112946] __arm64_sys_reboot+0x1c8/0x328 [ 22.113868] invoke_syscall+0x78/0x1a8 [ 22.114703] do_el0_svc+0x124/0x1a0 [ 22.115498] el0_svc+0x3c/0xe0 [ 22.116181] el0t_64_sync_handler+0x70/0xc0 [ 22.117110] el0t_64_sync+0x190/0x198 [ 22.117931] ---[ end trace 0000000000000000 ]---
Source
416baaa9-dc9f-4396-8d5f-8c081fb06d67
NVD status
Analyzed
Products
linux_kernel

Risk scores

CVSS 3.1

Type
Primary
Base score
5.5
Impact score
3.6
Exploitability score
1.8
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Severity
MEDIUM

Weaknesses

nvd@nist.gov
NVD-CWE-noinfo

Social media

Hype score
Not currently trending

Configurations

  1. In the Linux kernel, the following vulnerability has been resolved: coresight: tmc-etr: Fix race condition between sysfs and perf mode When trying to run perf and sysfs mode simultaneously, the WARN_ON() in tmc_etr_enable_hw() is triggered sometimes: WARNING: CPU: 42 PID: 3911571 at drivers/hwtracing/coresight/coresight-tmc-etr.c:1060 tmc_etr_enable_hw+0xc0/0xd8 [coresight_tmc] [..snip..] Call trace: tmc_etr_enable_hw+0xc0/0xd8 [coresight_tmc] (P) tmc_enable_etr_sink+0x11c/0x250 [coresight_tmc] (L) tmc_enable_etr_sink+0x11c/0x250 [coresight_tmc] coresight_enable_path+0x1c8/0x218 [coresight] coresight_enable_sysfs+0xa4/0x228 [coresight] enable_source_store+0x58/0xa8 [coresight] dev_attr_store+0x20/0x40 sysfs_kf_write+0x4c/0x68 kernfs_fop_write_iter+0x120/0x1b8 vfs_write+0x2c8/0x388 ksys_write+0x74/0x108 __arm64_sys_write+0x24/0x38 el0_svc_common.constprop.0+0x64/0x148 do_el0_svc+0x24/0x38 el0_svc+0x3c/0x130 el0t_64_sync_handler+0xc8/0xd0 el0t_64_sync+0x1ac/0x1b0 ---[ end trace 0000000000000000 ]--- Since the enablement of sysfs mode is separeted into two critical regions, one for sysfs buffer allocation and another for hardware enablement, it's possible to race with the perf mode. Fix this by double check whether the perf mode's been used before enabling the hardware in sysfs mode. mode: [sysfs mode] [perf mode] tmc_etr_get_sysfs_buffer() spin_lock(&drvdata->spinlock) [sysfs buffer allocation] spin_unlock(&drvdata->spinlock) spin_lock(&drvdata->spinlock) tmc_etr_enable_hw() drvdata->etr_buf = etr_perf->etr_buf spin_unlock(&drvdata->spinlock) spin_lock(&drvdata->spinlock) tmc_etr_enable_hw() WARN_ON(drvdata->etr_buf) // WARN sicne etr_buf initialized at the perf side spin_unlock(&drvdata->spinlock) With this fix, we retain the check for CS_MODE_PERF in get_etr_sysfs_buf. This ensures we verify whether the perf mode's already running before we actually allocate the buffer. Then we can save the time of allocating/freeing the sysfs buffer if race with the perf mode.CVE-2026-46272