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: 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.
CVE-2020-14305 was later assigned to this issue. See also: https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2020-14305
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().
Use-after-free read in napi_gro_frags().
A flaw was found in the implementation of GRO, which allows an attacker with local access to trigger a use-after-free read in napi_gro_frags() and, potentially, crash the system.
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().
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.
mpt2sas: scheduling while atomic in _scsih_io_done().
ext4: a race between online resizing and write operations could lead to kernel crashes or data corruption.
ploop: potential corruption of the index during discard operation.
A race condition was discovered in ploop, which could lead to corruption of the index during discard operations in certain cases. Note. It is not recommended to manually unload the ReadyKernel patch with the fix for this issue while any discard operations for ploop images are in progress: the ploop images could be corrupted as a result. Upgrading the patch is OK, only manual unloads and downgrades can be problematic.
ploop: warn if a discard request is issued for the ploop header.
ve: detect removal of additional system libraries in the containers to simplify debugging.
Potential leak of a reference counter for a memory cgroup in memcg_expand_shrinker_maps().
Potential corruption of ploop images due to a race between the truncation thread and resize operations.
ve: make it easier to analyze removal of system libraries in the containers.
xfs: potential denial of service caused by missing unlock operation in xfs_setattr_nonsize().
It was discovered that xfs_setattr_nonsize() would not unlock 'ILOCK' lock if the user or group were out of their disk quota. As a result, any subsequent operation, which needed to take 'ILOCK', would get stuck, leading to a denial of service.
nf_tables: kernel crash in nft_rbtree_lookup().
ploop: holes in raw ploop images were handled incorrectly.
Kernel crash due to out-of-bounds memory accesses in process_vm_readv().
It was discovered that the implementation of process_vm_readv() system call could try to access memory outside of the structures it was processing in certain cases. A local unprivileged user could use this vulnerability to crash the system.
Certain operations with an empty ploop image could lead to its unexpected growth.
memcg: memory corruption caused by writing beyond the end of shrinker_map structure.
ploop: kernel crashes when processing discard requests for ploop images in raw format.
scsi: printing lots of messages about rejected I/O causes a hard lockup and a kernel crash.
Potential kernel crash in __radix_tree_insert() when fscache is used for NFS mounts.
sunrpc: potential kernel crash in bc_svc_process().
A bug in ploop prevented recovery of corrupted ploop images.
Kernel crash in the implementation of epoll_ctl system call.
Kernel crash in __generic_splice_read().
KVM: Out-of-bounds memory access via MMIO ring buffer.
An issue was found in the implementation of the coalesced MMIO write operation in KVM. The indices used to access an MMIO ring buffer could be supplied by a user-space process in the host system. An attacker with access to /dev/kvm could use this flaw to trigger out-of-bounds memory access and crash the host kernel or, potentially, escalate their privileges.
Potential kernel crash in __tcp_retransmit_skb().
It was discovered that a local unprivileged attacker could use a specially crafted sequence of system calls to trigger either a kernel crash in __tcp_retransmit_skb() or use-after-free conditions, which could result in privilege escalation.
Certain operations with iptables in a container may crash the kernel.
A container that tries to mount NFS shares may cause the whole system to hang in certain conditions.
tun: potential kernel crash when TUNSETIFF ioctl operation is used for a device with an invalid name.
Use-after-free in __blk_drain_queue() function.
It was found that a use-after-free condition could be triggered in the block device subsystem while the outstanding command queue was drained. A patient local attacker can use this flaw to crash the system or, potentially, to escalate their privileges.
sunrpc: kernel crash in svcauth_unix_set_client().
Base ploop images containing holes could become larger than needed after merge.
Data corruption in the EXT4 file system when truncating the extent index blocks.
Kernel complained about busy inodes after unmount of NFS shares and crashed in certain cases.
memcg: race condition between reparenting and kmem uncharging.
It was discovered that a race condition was possible between kmem uncharging and mem_cgroup_reparent_charges(). A kernel warning would be triggered as a result.
Kernel crashed in down_read() when a FUSE file system was exported via NFS.
vhost-net: guest to host kernel escape during migration
A buffer overflow vulnerability was found in the networking virtualization functionality (vhost-net) that could be abused during live migration of virtual machines. A privileged guest user may pass descriptors with invalid length to the host when live migration is underway to crash the host kernel or, potentially, escalate their privileges on the host.
Ploop image could grow over its limits in certain cases.
ploop: resize operation could fail due to an incorrect check in ploop1_allocate().
infiniband: use-after-free in ucma_leave_multicast().
It was found that ucma_leave_multicast() function from 'rdma_ucm' module could try to access a certain data structure after the structure had been freed. This allows an attacker to induce kernel memory corruption, leading to a system crash or other unspecified impact.
Page cache side channel attacks via mincore().
It was discovered that a local attacker could exploit mincore() system call to obtain information about memory pages of the running applications from the page cache even if the contents of these memory pages were not available to the attacker.
The warning in mem_cgroup_reparent_charges() was triggered too early and too often in certain cases.
kvm: potential system hang due to an error in mmu_shrink_scan().
nfs: NULL pointer dereference due to an anomalized NFS message sequence.
An attacker, who is able to mount an exported NFS filesystem, is able to trigger a null pointer dereference by using an invalid NFS sequence. This can panic the machine and deny access to the NFS server. Any outstanding disk writes to the NFS server will be lost.
Storage: certain errors in CS caused by power failures were not handled properly.
It was discovered that if a file located on Virtuozzo Storage cluster was reopened, the kernel could reuse its mappings without notifying MDS. As a result, if errors were then detected on a CS, for example, caused by power failures, the userspace components would be unable to handle them properly.
Processes could get stuck in copy_net_ns() forever.
vziolimit: kernel crash due to a division by zero in throttle_charge().
pcompact operation is much slower for the containers on Virtuozzo Storage than for the ones stored locally.