A specially crafted program running in a container could make certain processes on the host hang (denial of service).
Kernel crash in mem_cgroup_from_cont() due to a race between memory reclaim and offlining of a cgroup.
ploop: certain operations with large ploop images could lead to a division by zero in __map_extent_bmap().
nfsd: Potential kernel crash in nfs4_put_stid().
'ploop grow' operation could fail in certain cases if the ploop image file contained holes.
Processes being killed by the OOM killer could continue consuming memory.
If a process running in a container performed large allocations of kernel memory, this could hit the memory limit for the container and trigger the OOM killer. It was discovered, however, that the process being killed by it could continue consuming memory for some time. This could lead to out of memory conditions on the host.
bcache: Potential kernel crash when using RAID1 as a backing device.
ploop: Potential kernel crash or data corruption during backups due to racy operations with lockout data.
netfilter/ipset: excessive memory consumption leading to a denial of service.
If was discovered that not all memory allocated for ipset-related data was properly accounted for. An attacker could exploit it from a container to consume lots of kernel memory, making the host system unusable (denial of service).
NFS v4: potential memory corruption on the client system when processing security attributes.
It was discovered that a buffer overflow and memory corruption were possible if a system tried to mount an NFS v4 share where the files had security labels in the file attributes. An attacker would need to control the NFS server and make it send a specific series of responses to trigger the issue. The issue allows the attacker to crash the kernel on the client system or, potentially, escalate their privileges there.
netfilter: kernel crash due to a buffer overflow in ctnetlink_parse_tuple_filter().
It was discovered that a local attacker could pass a specially crafted configuration of conntrack to the kernel to cause a buffer overflow in ctnetlink_parse_tuple_filter() function. As a result, the kernel could crash.
Potential kernel crash (use-after-free) in the implementation of usermode helpers.
A race condition was discovered in the implementation of usermode helpers in the kernel. An attacker could exploit it from a container to cause a denial-of-service (kernel crash due to a use-after-free), or, potentially, to escalate their privileges in the system.
nf_tables: kernel crash in nf_tables_getset().
It was discovered that the implementation of nf_tables did not properly validate certain parameters. An attacker could exploit this from a container to cause a kernel crash: NULL pointer dereference or a general protection fault in nf_tables_getset().
nfnetlink: potential kernel crash (skb_over_panic) in skb_put().
It was discovered that nfnetlink subsystem did not properly validate certain messages. An attacker could exploit this from a container to cause a kernel crash: skb_over_panic in skb_put().
Memory reclaim could become too slow leading to high LA on the nodes.
The original fix for PSBM-99181 and related issues introduced a problem: management of shrinkers used to reclaim memory could become very inefficient in certain cases, causing higher load on the affected nodes.
nf_conntrack: potential kernel crash in nf_ct_gre_keymap_destroy().
memcg: the limit on page cache (memory.cache.limit_in_bytes) could be exceeded significantly in certain cases.
File system of a container becomes read-only, __ext4_handle_dirty_metadata() reports error 28.
Possible use-after-free error due to a race condition in cdev_get().
It was discovered that use-after-free condition was possible in cdev_get() if multiple processes simultaneously accessed a character device in a certain way. A local attacker could potentially exploit this to crash the kernel.
memcg: kernel crash in memcg_destroy_kmem_caches() caused by unbalanced css_tryget/css_put operations.
Hard lockup and kernel crash caused by incorrect locking in calc_load_ve().
af_packet: potential soft lockup in case of certain errors when using TPACKET_V3.
It was found that if TPACKET_V3 was used and the kernel failed to obtain certain settings from a relevant network device, the retirement timer could be set incorrectly in the implementation AF_PACKET protocol. This could result in soft lockups and excessive CPU usage.
netlabel: kernel crash (null pointer dereference) while processing a specially crafted CIPSO packet.
A NULL pointer dereference was found in the implementation of SELinux. The issue occurs while importing the Commercial IP Security Option (CIPSO) protocol category bitmap into SELinux extensible bitmap. Parsing of a specially crafted CIPSO packet sent by a remote attacker could lead to a kernel crash (remote DoS).
Core dumps of some processes could contain uninitialized kernel data.
It was discovered that core dumps of userspace processes could contain copies of uninitialized kernel memory areas in certain cases. Although it is difficult for an attacker to control what data is in these areas, this issue, in theory, could be used to obtain sensitive information from the kernel.
crypto/authenc: kernel crash in crypto_ahash_setkey() when payload of a key is longer than 4 bytes and is not aligned.
An out-of-bounds read was found in the implementation of IPsec cryptographic algorithms ('authenc' module). When payload of a key was longer than 4 bytes but was not properly aligned, crypto_authenc_extractkeys() function could try to read data from a wrong location. This could lead to a kernel crash in crypto_ahash_setkey().
ploop: kernel crash (division by zero) in purge_lru_warn().
Denial of service by corrupting mountpoint reference counter.
It was discovered that a race condition was possible between pivot_root() and put_mountpoint() operations. A local unprivileged attacker could exploit this to corrupt mountpoint reference counter and cause a denial of service (kernel crash).
ext4: potential kernel crash in ext4_cross_rename(): certain error cases were not checked properly.
ext4: use-after-free when unmounting a corrupted file system with files that have no links.
futex: potential system hang due to a missing unlock operation in the error path of futex_wait_requeue_pi().
cbt: potential endless loops in the error paths.
netfilter: potential memory corruption caused by a helper from nf_conntrack_h323 module.
nf_conntrack: potential kernel crash in netlink_has_listeners().
ext4: attempts to freeze the FS could hang in certain cases due to an unbalanced internal write counter.
netlink: performance issues due to direct memory reclaim in netlink_dump() and netlink_trim().
memcg: kernel could crash when memory was uncharged from a cgroup while the cgroup was going offline.
It was found that a race was possible between uncharging memory from a cgroup and making that cgroup offline. This could lead to premature destruction of the cgroup and could cause a kernel crash.
packet: packet_sk_charge() could try to charge zero memory, leading to a use-after-free in memcg subsystem.
memcg: potential use-after-free in the implementation of uncharge operations.
qxl: kernel crash in qxl_release_fence_buffer_objects().
i40iw: kernel complains about failed RTNL assertion in i40iw_addr_resolve_neigh().
Slow memory allocations in nf_conntrack when a netns is created.
When a new netns is created, high-order page allocations can happen in nf_ct_alloc_hashtable(). If memory is fragmented, such allocations can become very slow due to memory reclaim, etc. This, in turn, could result in significant slowdowns on the node.
nfsd: memory corruption in nfsd4_lock().
Potential hard lockups in timer-related code: jiffies_lock could be held for a long time.
(enhancement) ploop: added interface to dump the cached BAT.
It was discovered that containers could get a broken on-disk BAT but have healthy in-kernel data in certain cases. To detect and fix such conditions, the means to dump the cached BAT were implemented in ploop. Note that, to make use of this enhancement, version 126.96.36.199 or newer of the userspace ploop tools is needed.
netfilter: kernel crash in the implementation of nf_tables due to use-after-free in dynamic operations.
A container with NFS server could force other such containers to use the older NFSv4 client tracker, which slows down NFS mounts.
ext4: potential kernel crash (general protection fault) in ext4_free_blocks().
mpt2sas: scheduling while atomic in _scsih_io_done().