Affected: Alpaquita:23: linux-lts, Alpaquita:25: linux-lts, Alpaquita:stream: linux-lts

In the Linux kernel, the following vulnerability has been resolved:

drm/amdkfd: Destroy KFD debugfs after destroy KFD wq

Since KFD proc content was moved to kernel debugfs, we can't destroy KFD debugfs before kfd_process_destroy_wq. Move kfd_process_destroy_wq prior to kfd_debugfs_fini to fix a kernel NULL pointer problem. It happens when /sys/kernel/debug/kfd was already destroyed in kfd_debugfs_fini but kfd_process_destroy_wq calls kfd_debugfs_remove_process. This line debugfs_remove_recursive(entry->proc_dentry); tries to remove /sys/kernel/debug/kfd/proc/<pid> while /sys/kernel/debug/kfd is already gone. It hangs the kernel by kernel NULL pointer.

(cherry picked from commit 0333052d90683d88531558dcfdbf2525cc37c233)

In the Linux kernel, the following vulnerability has been resolved:

drm/amdkfd: Destroy KFD debugfs after destroy KFD wq

Since KFD proc content was moved to kernel debugfs, we can't destroy KFD debugfs before kfd_process_destroy_wq. Move kfd_process_destroy_wq prior to kfd_debugfs_fini to fix a kernel NULL pointer problem. It happens when /sys/kernel/debug/kfd was already destroyed in kfd_debugfs_fini but kfd_process_destroy_wq calls kfd_debugfs_remove_process. This line debugfs_remove_recursive(entry->proc_dentry); tries to remove /sys/kernel/debug/kfd/proc/<pid> while /sys/kernel/debug/kfd is already gone. It hangs the kernel by kernel NULL pointer.

(cherry picked from commit 0333052d90683d88531558dcfdbf2525cc37c233)

In the Linux kernel, the following vulnerability has been resolved: drm/amd/display: Check link_res->hpo_dp_link_enc before using it [WHAT & HOW] Functions dp_enable_link_phy and dp_disable_link_phy can pass link_res without initializing hpo_dp_link_enc and it is necessary to check for null before dereferencing. This fixes 2 FORWARD_NULL issues reported by Coverity. In the Linux kernel, the following vulnerability has been resolved:

fs: relax assertions on failure to encode file handles

Encoding file handles is usually performed by a filesystem >encode_fh() method that may fail for various reasons.

The legacy users of exportfs_encode_fh(), namely, nfsd and name_to_handle_at(2) syscall are ready to cope with the possibility of failure to encode a file handle.

There are a few other users of exportfs_encode_{fh,fid}() that currently have a WARN_ON() assertion when ->encode_fh() fails. Relax those assertions because they are wrong.

The second linked bug report states commit 16aac5ad1fa9 ("ovl: support encoding non-decodable file handles") in v6.6 as the regressing commit, but this is not accurate.

The aforementioned commit only increases the chances of the assertion and allows triggering the assertion with the reproducer using overlayfs, inotify and drop_caches.

Triggering this assertion was always possible with other filesystems and other reasons of ->encode_fh() failures and more particularly, it was also possible with the exact same reproducer using overlay…

Security update for the Linux Kernel

In the Linux kernel, the following vulnerability has been resolved: drm/amd/display: Check link_res->hpo_dp_link_enc before using it [WHAT & HOW] Functions dp_enable_link_phy and dp_disable_link_phy can pass link_res without initializing hpo_dp_link_enc and it is necessary to check for null before dereferencing. This fixes 2 FORWARD_NULL issues reported by Coverity. In the Linux kernel, the following vulnerability has been resolved:

fs: relax assertions on failure to encode file handles

Encoding file handles is usually performed by a filesystem >encode_fh() method that may fail for various reasons.

The legacy users of exportfs_encode_fh(), namely, nfsd and name_to_handle_at(2) syscall are ready to cope with the possibility of failure to encode a file handle.

There are a few other users of exportfs_encode_{fh,fid}() that currently have a WARN_ON() assertion when ->encode_fh() fails. Relax those assertions because they are wrong.

The second linked bug report states commit 16aac5ad1fa9 ("ovl: support encoding non-decodable file handles") in v6.6 as the regressing commit, but this is not accurate.

The aforementioned commit only increases the chances of the assertion and allows triggering the assertion with the reproducer using overlayfs, inotify and drop_caches.

Triggering this assertion was always possible with other filesystems and other reasons of ->encode_fh() failures and more particularly, it was also possible with the exact same reproducer using overlay…

Security update for the Linux Kernel

Affected: Ubuntu:Pro:14.04:LTS: linux, Ubuntu:Pro:14.04:LTS: linux-aws, Ubuntu:Pro:14.04:LTS: linux-azure, Ubuntu:Pro:14.04:LTS: linux-lts-xenial, Ubuntu:Pro:16.04:LTS: linux, Ubuntu:Pro:16.04:LTS: linux-aws, Ubuntu:Pro:16.04:LTS: linux-aws-hwe, Ubuntu:Pro:16.04:LTS: linux-azure, Ubuntu:Pro:16.04:LTS: linux-gcp, Ubuntu:Pro:16.04:LTS: linux-hwe and 216 more

In the Linux kernel, the following vulnerability has been resolved: drm/amdkfd: Destroy KFD debugfs after destroy KFD wq Since KFD proc content was moved to kernel debugfs, we can't destroy KFD debugfs before kfd_process_destroy_wq. Move kfd_process_destroy_wq prior to kfd_debugfs_fini to fix a kernel NULL pointer problem. It happens when /sys/kernel/debug/kfd was already destroyed in kfd_debugfs_fini but kfd_process_destroy_wq calls kfd_debugfs_remove_process. This line debugfs_remove_recursive(entry->proc_dentry); tries to remove /sys/kernel/debug/kfd/proc/<pid> while /sys/kernel/debug/kfd is already gone. It hangs the kernel by kernel NULL pointer. (cherry picked from commit 0333052d90683d88531558dcfdbf2525cc37c233)

Ein Angreifer kann mehrere Schwachstellen im Linux Kernel ausnutzen, um einen Denial of Service Angriff durchzuführen oder nicht näher spezifizierte Auswirkungen zu erzielen.