CVE-2021-4093

A flaw was found in the KVM's AMD code for supporting the Secure Encrypted Virtualization-Encrypted State (SEV-ES). A KVM guest using SEV-ES can trigger out-of-bounds reads and writes in the host kernel via a malicious VMGEXIT for a string I/O instruction (for example, outs or ins) using the exit reason SVM_EXIT_IOIO. This issue results in a crash of the entire system or a potential guest-to-host escape scenario.

The kernel packages contain the Linux kernel, the core of any Linux operating system.

Security Fix(es):

• kernel: fget: check that the fd still exists after getting a ref to it (CVE-2021-4083)

• kernel: avoid cyclic entity chains due to malformed USB descriptors (CVE-2020-0404)

• kernel: speculation on incompletely validated data on IBM Power9 (CVE-2020-4788)

• kernel: integer overflow in k_ascii() in drivers/tty/vt/keyboard.c (CVE-2020-13974)

• kernel: out-of-bounds read in bpf_skb_change_head() of filter.c due to a use-after-free (CVE-2021-0941)

• kernel: joydev: zero size passed to joydev_handle_JSIOCSBTNMAP() (CVE-2021-3612)

• kernel: reading /proc/sysvipc/shm does not scale with large shared memory segment counts (CVE-2021-3669)

• kernel: out-of-bound Read in qrtr_endpoint_post in net/qrtr/qrtr.c (CVE-2021-3743)

• kernel: crypto: ccp - fix resource leaks in ccp_run_aes_gcm_cmd() (CVE-2021-3744)

• kernel: possible use-after-free in bluetooth module (CVE-2021-3752)

• kernel: unaccounted ipc objects in Linux kernel lead to breaking memcg limits and DoS attacks (CVE-2021-3759)

• kernel: DoS in ccp_run_aes_gcm_cmd() function (CVE-2021-3764)

• kernel: sctp: Invalid chunks may be used to remotely remove existing associations (CVE-2021-3772)

• kernel: lack of port sanity checking in natd and netfilter leads to exploit of OpenVPN clients (CVE-2021-3773)

• kernel: possible leak or coruption of data residing on hugetlbfs (CVE-2021-4002)

• kernel: security regression for CVE-2018-13405 (CVE-2021-4037)

• kernel: Buffer overwrite in decode_nfs_fh function (CVE-2021-4157)

• kernel: cgroup: Use open-time creds and namespace for migration perm checks (CVE-2021-4197)

• kernel: Race condition in races in sk_peer_pid and sk_peer_cred accesses (CVE-2021-4203)

• kernel: new DNS Cache Poisoning Attack based on ICMP fragment needed packets replies (CVE-2021-20322)

• kernel: arm: SIGPAGE information disclosure vulnerability (CVE-2021-21781)

• hw: cpu: LFENCE/JMP Mitigation Update for CVE-2017-5715 (CVE-2021-26401)

• kernel: Local privilege escalation due to incorrect BPF JIT branch displacement computation (CVE-2021-29154)

• kernel: use-after-free in hso_free_net_device() in drivers/net/usb/hso.c (CVE-2021-37159)

• kernel: eBPF multiplication integer overflow in prealloc_elems_and_freelist() in kernel/bpf/stackmap.c leads to out-of-bounds write (CVE-2021-41864)

• kernel: Heap buffer overflow in firedtv driver (CVE-2021-42739)

• kernel: ppc: kvm: allows a malicious KVM guest to crash the host (CVE-2021-43056)

• kernel: an array-index-out-bounds in detach_capi_ctr in drivers/isdn/capi/kcapi.c (CVE-2021-43389)

• kernel: mwifiex_usb_recv() in drivers/net/wireless/marvell/mwifiex/usb.c allows an attacker to cause DoS via crafted USB device (CVE-2021-43976)

• kernel: use-after-free in the TEE subsystem (CVE-2021-44733)

• kernel: information leak in the IPv6 implementation (CVE-2021-45485)

• kernel: information leak in the IPv4 implementation (CVE-2021-45486)

• hw: cpu: intel: Branch History Injection (BHI) (CVE-2022-0001)

• hw: cpu: intel: Intra-Mode BTI (CVE-2022-0002)

• kernel: Local denial of service in bond_ipsec_add_sa (CVE-2022-0286)

• kernel: DoS in sctp_addto_chunk in net/sctp/sm_make_chunk.c (CVE-2022-0322)

• kernel: FUSE allows UAF reads of write() buffers, allowing theft of (partial) /etc/shadow hashes (CVE-2022-1011)

• kernel: use-after-free in nouveau kernel module (CVE-2020-27820)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

Additional Changes:

For detailed information on changes in this release, see the Rocky Linux 8.6 Release Notes linked from the References section.

A flaw was found in the KVM's AMD code for supporting the Secure Encrypted Virtualization-Encrypted State (SEV-ES). A KVM guest using SEV-ES can trigger out-of-bounds reads and writes in the host kernel via a malicious VMGEXIT for a string I/O instruction (for example, outs or ins) using the exit reason SVM_EXIT_IOIO. This issue results in a crash of the entire system or a potential guest-to-host escape scenario.

• ALSA: pcm: Fix races among concurrent prealloc proc writes {CVE-2022-1048}
• ALSA: pcm: Fix races among concurrent prepare and hw_params/hw_free calls {CVE-2022-1048}
• ALSA: pcm: Fix races among concurrent read/write and buffer changes {CVE-2022-1048}
• ALSA: pcm: Fix races among concurrent hw_params and hw_free calls {CVE-2022-1048}
• x86/elf: Disable automatic READ_IMPLIES_EXEC on 64-bit {CVE-2022-25265}
• x86/elf: Split READ_IMPLIES_EXEC from executable PT_GNU_STACK {CVE-2022-25265}
• x86/elf: Add table to document READ_IMPLIES_EXEC {CVE-2022-25265}
• KVM: SEV-ES: fix another issue with string I/O VMGEXITs {CVE-2021-4093}
• KVM: SEV-ES: go over the sev_pio_data buffer in multiple passes if needed {CVE-2021-4093}
• KVM: SEV-ES: keep INS functions together {CVE-2021-4093}
• KVM: x86: remove unnecessary arguments from complete_emulator_pio_in {CVE-2021-4093}
• KVM: x86: split the two parts of emulator_pio_in {CVE-2021-4093}
• KVM: x86: leave vcpu->arch.pio.count alone in emulator_pio_in_out {CVE-2021-4093}
• KVM: SEV-ES: clean up kvm_sev_es_ins/outs {CVE-2021-4093}
• KVM: SEV-ES: rename guest_ins_data to sev_pio_data {CVE-2021-4093}
• KVM: SEV-ES: fix length of string I/O {CVE-2021-4093}
• drm/i915: fix TLB invalidation for Gen12 video and compute engines {CVE-2022-4139}
• drm/i915: Flush TLBs before releasing backing store {CVE-2022-0330}
• xfs: fix up non-directory creation in SGID directories {CVE-2021-4037}
• tcp: Fix data races around icsk->icsk_af_ops. {CVE-2022-3566}
• ipv6: Fix data races around sk->sk_prot. {CVE-2022-3567}
• ipv6: annotate some data-races around sk->sk_prot {CVE-2022-3567}
• ipv6: use indirect call wrappers for {tcp, udpv6}_{recv, send}msg() {CVE-2022-3567}
• netfilter: nf_tables: deactivate anonymous set from preparation phase {CVE-2023-32233}
• netfilter: nf_tables: bogus EBUSY when deleting set after flush
• media: dmxdev: fix UAF when dvb_register_device() fails {CVE-2022-41218}
• l2tp: Don't sleep and disable BH under writer-side sk_callback_lock {CVE-2022-4129}
• l2tp: Serialize access to sk_user_data with sk_callback_lock {CVE-2022-4129}
• net: fix a concurrency bug in l2tp_tunnel_register() {CVE-2022-4129}
• Bluetooth: L2CAP: Fix memory leak in vhci_write {CVE-2022-3619}
• Bluetooth: L2CAP: Fix handling fragmented length
• wifi: brcmfmac: Fix potential buffer overflow in brcmf_fweh_event_worker() {CVE-2022-3628}
• wifi: cfg80211: avoid nontransmitted BSS list corruption {CVE-2022-42721}
• cfg80211: scan: fix RCU in cfg80211_add_nontrans_list()
• wifi: cfg80211: fix BSS refcounting bugs {CVE-2022-42720}
• cfg80211: hold bss_lock while updating nontrans_list
• ALSA: pcm: Move rwsem lock inside snd_ctl_elem_read to prevent UAF {CVE-2023-0266}
• ALSA: control: Drop superfluous snd_power_wait() calls
• ALSA: control: Track in-flight control read/write/tlv accesses
• Bluetooth: L2CAP: Fix use-after-free caused by l2cap_reassemble_sdu {CVE-2022-3564}
• netfilter: nf_conntrack_irc: Tighten matching on DCC message {CVE-2022-2663}
• netfilter: nf_conntrack_irc: Fix forged IP logic {CVE-2022-2663}
• KVM: x86: Avoid theoretical NULL pointer dereference in kvm_irq_delivery_to_apic_fast() {CVE-2022-2153}
• KVM: Add infrastructure and macro to mark VM as bugged
• KVM: x86/mmu: fix NULL pointer dereference on guest INVPCID {CVE-2022-1789}
• tcp/udp: Fix memory leak in ipv6_renew_options(). {CVE-2022-3524}
• proc: proc_skip_spaces() shouldn't think it is working on C strings {CVE-2022-4378}
• proc: avoid integer type confusion in get_proc_long {CVE-2022-4378}
• wifi: mac80211: fix crash in beacon protection for P2P-device {CVE-2022-42722}
• net: sched: cbq: dont intepret cls results when asked to drop {CVE-2023-23454}
• ipv6: raw: Deduct extension header length in rawv6_push_pending_frames {CVE-2023-0394}
• net: sched: disallow noqueue for qdisc classes {CVE-2022-47929}
• wifi: cfg80211: fix u8 overflow in cfg80211_update_notlisted_nontrans() {CVE-2022-41674}
• af_key: Do not call xfrm_probe_algs in…

Jeremy Cline discovered a use-after-free in the nouveau graphics driver of the Linux kernel during device removal. A privileged or physically proximate attacker could use this to cause a denial of service (system crash). (CVE-2020-27820)

It was discovered that the Bluetooth subsystem in the Linux kernel contained a use-after-free vulnerability. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2021-3640)

Likang Luo discovered that a race condition existed in the Bluetooth subsystem of the Linux kernel, leading to a use-after-free vulnerability. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2021-3752)

It was discovered that the SCTP protocol implementation in the Linux kernel did not properly verify VTAGs in some situations. A remote attacker could possibly use this to cause a denial of service (connection disassociation). (CVE-2021-3772)

It was discovered that the eBPF implementation in the Linux kernel contained a race condition around read-only maps. A privileged attacker could use this to modify read-only maps. (CVE-2021-4001)

It was discovered that the NFS server implementation in the Linux kernel contained an out-of-bounds write vulnerability. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2021-4090)

Felix Wilhelm discovered that the KVM implementation in the Linux kernel did not properly handle exit events from AMD Secure Encrypted Virtualization-Encrypted State (SEV-ES) guest VMs. An attacker in a guest VM could use this to cause a denial of service (host kernel crash) or possibly execute arbitrary code in the host kernel. (CVE-2021-4093)

Lin Ma discovered that the NFC Controller Interface (NCI) implementation in the Linux kernel contained a race condition, leading to a use-after-free vulnerability. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2021-4202)

It was discovered that the AMD Radeon GPU driver in the Linux kernel did not properly validate writes in the debugfs file system. A privileged attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2021-42327)

Luo Likang discovered that the FireDTV Firewire driver in the Linux kernel did not properly perform bounds checking in some situations. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2021-42739)