Ubuntu: (Multiple Advisories) (CVE-2024-39486): Linux kernel vulnerabilities
Description
In the Linux kernel, the following vulnerability has been resolved: drm/drm_file: Fix pid refcounting race <maarten.lankhorst@linux.intel.com>, Maxime Ripard <mripard@kernel.org>, Thomas Zimmermann <tzimmermann@suse.de> 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
- Lightweight Endpoint Agent
- Live Dashboards
- Real Risk Prioritization
- IT-Integrated Remediation Projects
- Cloud, Virtual, and Container Assessment
- Integrated Threat Feeds
- Easy-to-Use RESTful API
- Automation-Assisted Patching
- Automated Containment
With Rapid7 live dashboards, I have a clear view of all the assets on my network, which ones can be exploited, and what I need to do in order to reduce the risk in my environment in real-time. No other tool gives us that kind of value and insight.
– Scott Cheney, Manager of Information Security, Sierra View Medical Center