Ubuntu: (Multiple Advisories) (CVE-2024-39486): Linux kernel kernel vulnerabilities

Ubuntu: (Multiple Advisories) (CVE-2024-39486): Linux kernel kernel vulnerabilities

Severity

7

CVSS

(AV:L/AC:M/Au:S/C:C/I:C/A:C)

Published

07/06/2024

Created

11/05/2024

Added

11/04/2024

Modified

01/30/2025

Description

In the Linux kernel, the following vulnerability has been resolved: drm/drm_file: Fix pid refcounting race <[email protected]>, Maxime Ripard <[email protected]>, Thomas Zimmermann <[email protected]> filp->pid is supposed to be a refcounted pointer; however, before this patch, drm_file_update_pid() only increments the refcount of a struct pid after storing a pointer to it in filp->pid and dropping the dev->filelist_mutex, making the following race possible: process A process B ========= ========= begin drm_file_update_pid mutex_lock(&dev->filelist_mutex) rcu_replace_pointer(filp->pid, <pid B>, 1) mutex_unlock(&dev->filelist_mutex) begin drm_file_update_pid mutex_lock(&dev->filelist_mutex) rcu_replace_pointer(filp->pid, <pid A>, 1) mutex_unlock(&dev->filelist_mutex) get_pid(<pid A>) synchronize_rcu() put_pid(<pid B>) *** pid B reaches refcount 0 and is freed here *** get_pid(<pid B>) *** UAF *** synchronize_rcu() put_pid(<pid A>) As far as I know, this race can only occur with CONFIG_PREEMPT_RCU=y because it requires RCU to detect a quiescent state in code that is not explicitly calling into the scheduler. This race leads to use-after-free of a "struct pid". It is probably somewhat hard to hit because process A has to pass through a synchronize_rcu() operation while process B is between mutex_unlock() and get_pid(). Fix it by ensuring that by the time a pointer to the current task's pid is stored in the file, an extra reference to the pid has been taken. This fix also removes the condition for synchronize_rcu(); I think that optimization is unnecessary complexity, since in that case we would usually have bailed out on the lockless check above.

Solution(s)

• ubuntu-upgrade-linux-image-6-8-0-1002-gkeop
• ubuntu-upgrade-linux-image-6-8-0-1013-gke
• ubuntu-upgrade-linux-image-6-8-0-1014-ibm
• ubuntu-upgrade-linux-image-6-8-0-1014-raspi
• ubuntu-upgrade-linux-image-6-8-0-1015-oracle
• ubuntu-upgrade-linux-image-6-8-0-1015-oracle-64k
• ubuntu-upgrade-linux-image-6-8-0-1016-azure
• ubuntu-upgrade-linux-image-6-8-0-1016-azure-fde
• ubuntu-upgrade-linux-image-6-8-0-1016-gcp
• ubuntu-upgrade-linux-image-6-8-0-1016-oem
• ubuntu-upgrade-linux-image-6-8-0-1017-azure
• ubuntu-upgrade-linux-image-6-8-0-1017-azure-fde
• ubuntu-upgrade-linux-image-6-8-0-1017-gcp
• ubuntu-upgrade-linux-image-6-8-0-1017-nvidia
• ubuntu-upgrade-linux-image-6-8-0-1017-nvidia-64k
• ubuntu-upgrade-linux-image-6-8-0-1017-nvidia-lowlatency
• ubuntu-upgrade-linux-image-6-8-0-1017-nvidia-lowlatency-64k
• ubuntu-upgrade-linux-image-6-8-0-1018-aws
• ubuntu-upgrade-linux-image-6-8-0-48-generic
• ubuntu-upgrade-linux-image-6-8-0-48-generic-64k
• ubuntu-upgrade-linux-image-6-8-0-48-lowlatency
• ubuntu-upgrade-linux-image-6-8-0-48-lowlatency-64k
• ubuntu-upgrade-linux-image-aws
• ubuntu-upgrade-linux-image-azure
• ubuntu-upgrade-linux-image-azure-fde
• ubuntu-upgrade-linux-image-gcp
• ubuntu-upgrade-linux-image-generic
• ubuntu-upgrade-linux-image-generic-64k
• ubuntu-upgrade-linux-image-generic-64k-hwe-22-04
• ubuntu-upgrade-linux-image-generic-64k-hwe-24-04
• ubuntu-upgrade-linux-image-generic-hwe-22-04
• ubuntu-upgrade-linux-image-generic-hwe-24-04
• ubuntu-upgrade-linux-image-generic-lpae
• ubuntu-upgrade-linux-image-gke
• ubuntu-upgrade-linux-image-gkeop
• ubuntu-upgrade-linux-image-gkeop-6-8
• ubuntu-upgrade-linux-image-ibm
• ubuntu-upgrade-linux-image-ibm-classic
• ubuntu-upgrade-linux-image-ibm-lts-24-04
• ubuntu-upgrade-linux-image-kvm
• ubuntu-upgrade-linux-image-lowlatency
• ubuntu-upgrade-linux-image-lowlatency-64k
• ubuntu-upgrade-linux-image-lowlatency-64k-hwe-22-04
• ubuntu-upgrade-linux-image-lowlatency-64k-hwe-24-04
• ubuntu-upgrade-linux-image-lowlatency-hwe-22-04
• ubuntu-upgrade-linux-image-lowlatency-hwe-24-04
• ubuntu-upgrade-linux-image-nvidia
• ubuntu-upgrade-linux-image-nvidia-6-8
• ubuntu-upgrade-linux-image-nvidia-64k
• ubuntu-upgrade-linux-image-nvidia-64k-6-8
• ubuntu-upgrade-linux-image-nvidia-64k-hwe-22-04
• ubuntu-upgrade-linux-image-nvidia-hwe-22-04
• ubuntu-upgrade-linux-image-nvidia-lowlatency
• ubuntu-upgrade-linux-image-nvidia-lowlatency-64k
• ubuntu-upgrade-linux-image-oem-22-04
• ubuntu-upgrade-linux-image-oem-22-04a
• ubuntu-upgrade-linux-image-oem-22-04b
• ubuntu-upgrade-linux-image-oem-22-04c
• ubuntu-upgrade-linux-image-oem-22-04d
• ubuntu-upgrade-linux-image-oem-24-04
• ubuntu-upgrade-linux-image-oem-24-04a
• ubuntu-upgrade-linux-image-oracle
• ubuntu-upgrade-linux-image-oracle-64k
• ubuntu-upgrade-linux-image-raspi
• ubuntu-upgrade-linux-image-virtual
• ubuntu-upgrade-linux-image-virtual-hwe-22-04
• ubuntu-upgrade-linux-image-virtual-hwe-24-04

References

• https://attackerkb.com/topics/cve-2024-39486
• CVE - 2024-39486
• USN-7089-1
• USN-7089-2
• USN-7089-3
• USN-7089-4
• USN-7089-5
• USN-7089-6
• USN-7089-7
• USN-7090-1
• USN-7095-1
• USN-7156-1

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