CVE-2024-50037
Description
From CVE.org
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 ]---
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 5.5 | 5.5 | N/A |
| Attack Vector | Local | Local | N/A |
| Attack Complexity | Low | Low | N/A |
| Privileges Required | Low | Low | N/A |
| User Interaction | None | None | N/A |
| Scope | Unchanged | Unchanged | N/A |
| Confidentiality | None | None | N/A |
| Integrity Impact | None | None | N/A |
| Availability Impact | High | High | N/A |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
NVD: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Crash, Exit, or Restart
Integrity,Confidentiality,Availability
Technical Impact: Execute Unauthorized Code or Commands; Read Memory; Modify Memory
In rare circumstances, when NULL is equivalent to the 0x0 memory address and privileged code can access it, then writing or reading memory is possible, which may lead to code execution.
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