CVE-2024-41094

Published Jul 29, 2024

Last updated 2 years ago

Overview

Description
In the Linux kernel, the following vulnerability has been resolved: drm/fbdev-dma: Only set smem_start is enable per module option Only export struct fb_info.fix.smem_start if that is required by the user and the memory does not come from vmalloc(). Setting struct fb_info.fix.smem_start breaks systems where DMA memory is backed by vmalloc address space. An example error is shown below. [ 3.536043] ------------[ cut here ]------------ [ 3.540716] virt_to_phys used for non-linear address: 000000007fc4f540 (0xffff800086001000) [ 3.552628] WARNING: CPU: 4 PID: 61 at arch/arm64/mm/physaddr.c:12 __virt_to_phys+0x68/0x98 [ 3.565455] Modules linked in: [ 3.568525] CPU: 4 PID: 61 Comm: kworker/u12:5 Not tainted 6.6.23-06226-g4986cc3e1b75-dirty #250 [ 3.577310] Hardware name: NXP i.MX95 19X19 board (DT) [ 3.582452] Workqueue: events_unbound deferred_probe_work_func [ 3.588291] pstate: 60400009 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) [ 3.595233] pc : __virt_to_phys+0x68/0x98 [ 3.599246] lr : __virt_to_phys+0x68/0x98 [ 3.603276] sp : ffff800083603990 [ 3.677939] Call trace: [ 3.680393] __virt_to_phys+0x68/0x98 [ 3.684067] drm_fbdev_dma_helper_fb_probe+0x138/0x238 [ 3.689214] __drm_fb_helper_initial_config_and_unlock+0x2b0/0x4c0 [ 3.695385] drm_fb_helper_initial_config+0x4c/0x68 [ 3.700264] drm_fbdev_dma_client_hotplug+0x8c/0xe0 [ 3.705161] drm_client_register+0x60/0xb0 [ 3.709269] drm_fbdev_dma_setup+0x94/0x148 Additionally, DMA memory is assumed to by contiguous in physical address space, which is not guaranteed by vmalloc(). Resolve this by checking the module flag drm_leak_fbdev_smem when DRM allocated the instance of struct fb_info. Fbdev-dma then only sets smem_start only if required (via FBINFO_HIDE_SMEM_START). Also guarantee that the framebuffer is not located in vmalloc address space.
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