Rogue backends can cause DoS of guests via high frequency events T[his CNA information record relates to multiple CVEs; the text explains which aspects/vulnerabilities correspond to which CVE.] Xen offers the ability to run PV backends in regular unprivileged guests, typically referred to as "driver domains". Running PV backends in driver domains has one primary security advantage: if a driver domain gets compromised, it doesn't have the privileges to take over the system. However, a malicious driver domain could try to attack other guests via sending events at a high frequency leading to a Denial of Service in the guest due to trying to service interrupts for elongated amounts of time. There are three affected backends: * blkfront patch 1, CVE-2021-28711 * netfront patch 2, CVE-2021-28712 * hvc_xen (console) patch 3, CVE-2021-28713

Guest can force Linux netback driver to hog large amounts of kernel memory T[his CNA information record relates to multiple CVEs; the text explains which aspects/vulnerabilities correspond to which CVE.] Incoming data packets for a guest in the Linux kernel's netback driver are buffered until the guest is ready to process them. There are some measures taken for avoiding to pile up too much data, but those can be bypassed by the guest: There is a timeout how long the client side of an interface can stop consuming new packets before it is assumed to have stalled, but this timeout is rather long (60 seconds by default). Using a UDP connection on a fast interface can easily accumulate gigabytes of data in that time. (CVE-2021-28715) The timeout could even never trigger if the guest manages to have only one free slot in its RX queue ring page and the next package would require more than one free slot, which may be the case when using GSO, XDP, or software hashing. (CVE-2021-28714)

A flaw was found in the Linux kernel in the function hid_debug_events_read() in drivers/hid/hid-debug.c file which may enter an infinite loop with certain parameters passed from a userspace. A local privileged user ("root") can cause a system lock up and a denial of service. Versions from v4.18 and newer are vulnerable.

pci_change_irq_level in hw/pci/pci.c in QEMU before 5.1.1 has a NULL pointer dereference because pci_get_bus() might not return a valid pointer.

A memory leak in rsyslog before 5.7.6 was found in the way deamon processed log messages are logged when multiple rulesets were used and some output batches contained messages belonging to more than one ruleset. A local attacker could cause denial of the rsyslogd daemon service via a log message belonging to more than one ruleset

A memory leak in rsyslog before 5.7.6 was found in the way deamon processed log messages were logged when multiple rulesets were used and some output batches contained messages belonging to more than one ruleset. A local attacker could cause denial of the rsyslogd daemon service via a log message belonging to more than one ruleset.

QEMU (aka Quick Emulator), when built with the IDE disk and CD/DVD-ROM Emulator support, allows local guest OS privileged users to cause a denial of service (NULL pointer dereference and QEMU process crash) by flushing an empty CDROM device drive.

QEMU (aka Quick Emulator), when built with the VGA display emulator support, allows local guest OS privileged users to cause a denial of service (out-of-bounds read and QEMU process crash) via vectors involving display update.

The address_space_write_continue function in exec.c in QEMU (aka Quick Emulator) allows local guest OS privileged users to cause a denial of service (out-of-bounds access and guest instance crash) by leveraging use of qemu_map_ram_ptr to access guest ram block area.

The dhcp_decode function in slirp/bootp.c in QEMU (aka Quick Emulator) allows local guest OS users to cause a denial of service (out-of-bounds read and QEMU process crash) via a crafted DHCP options string.

Nullptr dereference when a null char is present in a proto symbol. The symbol is parsed incorrectly, leading to an unchecked call into the proto file's name during generation of the resulting error message. Since the symbol is incorrectly parsed, the file is nullptr. We recommend upgrading to version 3.15.0 or greater.

hw/rdma/rdma_backend.c in QEMU allows guest OS users to trigger out-of-bounds access via a PvrdmaSqWqe ring element with a large num_sge value.

An infinite loop flaw was found in the e1000 NIC emulator of the QEMU. This issue occurs while processing transmits (tx) descriptors in process_tx_desc if various descriptor fields are initialized with invalid values. This flaw allows a guest to consume CPU cycles on the host, resulting in a denial of service. The highest threat from this vulnerability is to system availability.

A flaw was found in the Netfilter subsystem of the Linux kernel. A race condition between IPSET_CMD_ADD and IPSET_CMD_SWAP can lead to a kernel panic due to the invocation of `__ip_set_put` on a wrong `set`. This issue may allow a local user to crash the system.

A NULL pointer dereference in vrend_renderer.c in virglrenderer through 0.8.0 allows guest OS users to cause a denial of service via malformed commands.

In QEMU 4.1.0, an out-of-bounds read flaw was found in the ATI VGA implementation. It occurs in the ati_cursor_define() routine while handling MMIO write operations through the ati_mm_write() callback. A malicious guest could abuse this flaw to crash the QEMU process, resulting in a denial of service.

In the Linux kernel before 5.1.6, there is a use-after-free in cpia2_exit() in drivers/media/usb/cpia2/cpia2_v4l.c that will cause denial of service, aka CID-dea37a972655.

An issue was discovered in button_open in login/logind-button.c in systemd before 243. When executing the udevadm trigger command, a memory leak may occur.

kernel/sched/fair.c in the Linux kernel before 5.3.9, when cpu.cfs_quota_us is used (e.g., with Kubernetes), allows attackers to cause a denial of service against non-cpu-bound applications by generating a workload that triggers unwanted slice expiration, aka CID-de53fd7aedb1. (In other words, although this slice expiration would typically be seen with benign workloads, it is possible that an attacker could calculate how many stray requests are required to force an entire Kubernetes cluster into a low-performance state caused by slice expiration, and ensure that a DDoS attack sent that number of stray requests. An attack does not affect the stability of the kernel; it only causes mismanagement of application execution.)

iproute2 before 5.1.0 has a use-after-free in get_netnsid_from_name in ip/ipnetns.c. NOTE: security relevance may be limited to certain uses of setuid that, although not a default, are sometimes a configuration option offered to end users. Even when setuid is used, other factors (such as C library configuration) may block exploitability.

A memory leak in the predicate_parse() function in kernel/trace/trace_events_filter.c in the Linux kernel through 5.3.11 allows attackers to cause a denial of service (memory consumption), aka CID-96c5c6e6a5b6.

Buffer overflow in the util_path_encode function in udev/lib/libudev-util.c in udev before 1.4.1 allows local users to cause a denial of service (service outage) via vectors that trigger a call with crafted arguments.

Two memory leaks in the mwifiex_pcie_init_evt_ring() function in drivers/net/wireless/marvell/mwifiex/pcie.c in the Linux kernel through 5.3.11 allow attackers to cause a denial of service (memory consumption) by triggering mwifiex_map_pci_memory() failures, aka CID-d10dcb615c8e.

Four memory leaks in the acp_hw_init() function in drivers/gpu/drm/amd/amdgpu/amdgpu_acp.c in the Linux kernel before 5.3.8 allow attackers to cause a denial of service (memory consumption) by triggering mfd_add_hotplug_devices() or pm_genpd_add_device() failures, aka CID-57be09c6e874. NOTE: third parties dispute the relevance of this because the attacker must already have privileges for module loading

In Libarchive 3.4.0, archive_wstring_append_from_mbs in archive_string.c has an out-of-bounds read because of an incorrect mbrtowc or mbtowc call. For example, bsdtar crashes via a crafted archive.

In the Linux kernel 5.3.11, mounting a crafted btrfs image twice can cause an rwsem_down_write_slowpath use-after-free because (in rwsem_can_spin_on_owner in kernel/locking/rwsem.c) rwsem_owner_flags returns an already freed pointer,

A memory leak in the ccp_run_sha_cmd() function in drivers/crypto/ccp/ccp-ops.c in the Linux kernel through 5.3.9 allows attackers to cause a denial of service (memory consumption), aka CID-128c66429247.

A memory leak in the mlx5_fpga_conn_create_cq() function in drivers/net/ethernet/mellanox/mlx5/core/fpga/conn.c in the Linux kernel before 5.3.11 allows attackers to cause a denial of service (memory consumption) by triggering mlx5_vector2eqn() failures, aka CID-c8c2a057fdc7.

In the Linux kernel, the following vulnerability has been resolved: dmaengine: fix NULL pointer in channel unregistration function __dma_async_device_channel_register() can fail. In case of failure, chan->local is freed (with free_percpu()), and chan->local is nullified. When dma_async_device_unregister() is called (because of managed API or intentionally by DMA controller driver), channels are unconditionally unregistered, leading to this NULL pointer: [ 1.318693] Unable to handle kernel NULL pointer dereference at virtual address 00000000000000d0 [...] [ 1.484499] Call trace: [ 1.486930] device_del+0x40/0x394 [ 1.490314] device_unregister+0x20/0x7c [ 1.494220] __dma_async_device_channel_unregister+0x68/0xc0 Look at dma_async_device_register() function error path, channel device unregistration is done only if chan->local is not NULL. Then add the same condition at the beginning of __dma_async_device_channel_unregister() function, to avoid NULL pointer issue whatever the API used to reach this function.

An issue was discovered in the Linux kernel before 5.0.19. There is an out-of-bounds array access in __xfrm_policy_unlink, which will cause denial of service, because verify_newpolicy_info in net/xfrm/xfrm_user.c mishandles directory validation.

The sd2_parse_rsrc_fork function in sd2.c in libsndfile allows attackers to have unspecified impact via vectors related to a (1) map offset or (2) rsrc marker, which triggers an out-of-bounds read.

Sander Bos discovered Apport's lock file was in a world-writable directory which allowed all users to prevent crash handling.

Memory leak in the v9fs_write function in hw/9pfs/9p.c in QEMU (aka Quick Emulator) allows local guest OS administrators to cause a denial of service (memory consumption) by leveraging failure to free an IO vector.

Memory leak in the v9fs_link function in hw/9pfs/9p.c in QEMU (aka Quick Emulator) allows local guest OS administrators to cause a denial of service (memory consumption) via vectors involving a reference to the source fid object.

Integer overflow in DxeImageVerificationHandler() EDK II may allow an authenticated user to potentially enable denial of service via local access.

Memory leak in the v9fs_xattrcreate function in hw/9pfs/9p.c in QEMU (aka Quick Emulator) allows local guest OS administrators to cause a denial of service (memory consumption and QEMU process crash) via a large number of Txattrcreate messages with the same fid number.

QEMU (aka Quick Emulator) built with the ColdFire Fast Ethernet Controller emulator support is vulnerable to an infinite loop issue. It could occur while receiving packets in 'mcf_fec_receive'. A privileged user/process inside guest could use this issue to crash the QEMU process on the host leading to DoS.

NVIDIA Virtual GPU Manager and the guest drivers contain a vulnerability in vGPU plugin, in which there is the potential to execute privileged operations, which may lead to denial of service. This affects vGPU version 8.x (prior to 8.4), version 9.x (prior to 9.4) and version 10.x (prior to 10.3).

Quick emulator (Qemu) built with the Cirrus CLGD 54xx VGA Emulator support is vulnerable to a divide by zero issue. It could occur while copying VGA data when cirrus graphics mode was set to be VGA. A privileged user inside guest could use this flaw to crash the Qemu process instance on the host, resulting in DoS.

Quick Emulator (Qemu) built with the 'chardev' backend support is vulnerable to a use after free issue. It could occur while hotplug and unplugging the device in the guest. A guest user/process could use this flaw to crash a Qemu process on the host resulting in DoS.

Memory leak in hw/net/eepro100.c in QEMU (aka Quick Emulator) allows local guest OS administrators to cause a denial of service (memory consumption and QEMU process crash) by repeatedly unplugging an i8255x (PRO100) NIC device.

Insufficient access control in subsystem for Intel (R) processor graphics in 6th, 7th, 8th and 9th Generation Intel(R) Core(TM) Processor Families; Intel(R) Pentium(R) Processor J, N, Silver and Gold Series; Intel(R) Celeron(R) Processor J, N, G3900 and G4900 Series; Intel(R) Atom(R) Processor A and E3900 Series; Intel(R) Xeon(R) Processor E3-1500 v5 and v6 and E-2100 Processor Families may allow an authenticated user to potentially enable denial of service via local access.

The cirrus_do_copy function in hw/display/cirrus_vga.c in QEMU (aka Quick Emulator), when cirrus graphics mode is VGA, allows local guest OS privileged users to cause a denial of service (divide-by-zero error and QEMU process crash) via vectors involving blit pitch values.

The imx_fec_do_tx function in hw/net/imx_fec.c in QEMU (aka Quick Emulator) does not properly limit the buffer descriptor count when transmitting packets, which allows local guest OS administrators to cause a denial of service (infinite loop and QEMU process crash) via vectors involving a buffer descriptor with a length of 0 and crafted values in bd.flags.

The v9fs_iov_vunmarshal function in fsdev/9p-iov-marshal.c in QEMU (aka Quick Emulator) allows local guest OS administrators to cause a denial of service (NULL pointer dereference and QEMU process crash) by sending an empty string parameter to a 9P operation.