CVE-2021-20196

A NULL pointer dereference flaw was found in the floppy disk emulator of QEMU. This issue occurs while processing read/write ioport commands if the selected floppy drive is not initialized with a block device. This flaw allows a privileged guest user to crash the QEMU process on the host, resulting in a denial of service. The highest threat from this vulnerability is to system availability.

QEMU is a FAST! processor emulator using dynamic translation to achieve good emulation speed.

Security Fix(es):

A flaw was found in the QXL display device emulation in QEMU. An integer overflow in the cursor_alloc() function can lead to the allocation of a small cursor object followed by a subsequent heap-based buffer overflow. This flaw allows a malicious privileged guest user to crash the QEMU process on the host or potentially execute arbitrary code within the context of the QEMU process.(CVE-2021-4206)

A flaw was found in the QXL display device emulation in QEMU. A double fetch of guest controlled values cursor->header.width and cursor->header.height can lead to the allocation of a small cursor object followed by a subsequent heap-based buffer overflow. A malicious privileged guest user could use this flaw to crash the QEMU process on the host or potentially execute arbitrary code within the context of the QEMU process.(CVE-2021-4207)

A NULL pointer dereference flaw was found in the floppy disk emulator of QEMU. This issue occurs while processing read/write ioport commands if the selected floppy drive is not initialized with a block device. This flaw allows a privileged guest user to crash the QEMU process on the host, resulting in a denial of service. The highest threat from this vulnerability is to system availability.(CVE-2021-20196)

A flaw was found in the virtio-net device of QEMU. This flaw was inadvertently introduced with the fix for CVE-2021-3748, which forgot to unmap the cached virtqueue elements on error, leading to memory leakage and other unexpected results. Affected QEMU version: 6.2.0.(CVE-2022-26353)

A flaw was found in the vhost-vsock device of QEMU. In case of error, an invalid element was not detached from the virtqueue before freeing its memory, leading to memory leakage and other unexpected results. Affected QEMU versions <= 6.2.0.(CVE-2022-26354)

Kernel-based Virtual Machine (KVM) offers a full virtualization solution for Linux on numerous hardware platforms. The virt:Rocky Linux module contains packages which provide user-space components used to run virtual machines using KVM. The packages also provide APIs for managing and interacting with the virtualized systems.

The following packages have been upgraded to a later upstream version: qemu-kvm (6.2.0), libvirt (8.0.0), libvirt-python (8.0.0), perl-Sys-Virt (8.0.0), seabios (1.15.0), libtpms (0.9.1). (BZ#1997410, BZ#2012802, BZ#2012806, BZ#2012813, BZ#2018392, BZ#2027716, BZ#2029355)

Security Fix(es):

• QEMU: virtio-net: heap use-after-free in virtio_net_receive_rcu (CVE-2021-3748)

• ntfs-3g: Out-of-bounds heap buffer access in ntfs_get_attribute_value() due to incorrect check of bytes_in_use value in MFT records (CVE-2021-33285)

• ntfs-3g: Heap buffer overflow triggered by a specially crafted Unicode string (CVE-2021-33286)

• ntfs-3g: Heap buffer overflow in ntfs_attr_pread_i() triggered by specially crafted NTFS attributes (CVE-2021-33287)

• ntfs-3g: Heap buffer overflow triggered by a specially crafted MFT section (CVE-2021-33289)

• ntfs-3g: Heap buffer overflow triggered by a specially crafted NTFS inode pathname (CVE-2021-35266)

• ntfs-3g: Stack buffer overflow triggered when correcting differences between MFT and MFTMirror sections (CVE-2021-35267)

• ntfs-3g: Heap buffer overflow in ntfs_inode_real_open() triggered by a specially crafted NTFS inode (CVE-2021-35268)

• ntfs-3g: Heap buffer overflow in ntfs_attr_setup_flag() triggered by a specially crafted NTFS attribute from MFT (CVE-2021-35269)

• ntfs-3g: NULL pointer dereference in ntfs_extent_inode_open() (CVE-2021-39251)

• ntfs-3g: Out-of-bounds read in ntfs_ie_lookup() (CVE-2021-39252)

• ntfs-3g: Out-of-bounds read in ntfs_runlists_merge_i() (CVE-2021-39253)

• ntfs-3g: Integer overflow in memmove() leading to heap buffer overflow in ntfs_attr_record_resize() (CVE-2021-39254)

• ntfs-3g: Out-of-bounds read ntfs_attr_find_in_attrdef() triggered by an invalid attribute (CVE-2021-39255)

• ntfs-3g: Heap buffer overflow in ntfs_inode_lookup_by_name() (CVE-2021-39256)

• ntfs-3g: Endless recursion from ntfs_attr_pwrite() triggered by an unallocated bitmap (CVE-2021-39257)

• ntfs-3g: Out-of-bounds reads in ntfs_attr_find() and ntfs_external_attr_find() (CVE-2021-39258)

• ntfs-3g: Out-of-bounds access in ntfs_inode_lookup_by_name() caused by an unsanitized attribute length (CVE-2021-39259)

• ntfs-3g: Out-of-bounds access in ntfs_inode_sync_standard_information() (CVE-2021-39260)

• ntfs-3g: Heap buffer overflow in ntfs_compressed_pwrite() (CVE-2021-39261)

• ntfs-3g: Out-of-bounds access in ntfs_decompress() (CVE-2021-39262)

• ntfs-3g: Heap buffer overflow in ntfs_get_attribute_value() caused by an unsanitized attribute (CVE-2021-39263)

• libnbd: nbdcopy: missing error handling may create corrupted destination image (CVE-2022-0485)

• hivex: stack overflow due to recursive call of _get_children() (CVE-2021-3622)

• nbdkit: NBD_OPT_STRUCTURED_REPLY injection on STARTTLS (CVE-2021-3716)

• libvirt: segmentation fault during VM shutdown can lead to vdsm hang (CVE-2021-3975)

• QEMU: NULL pointer dereference in mirror_wait_on_conflicts() in block/mirror.c (CVE-2021-4145)

• QEMU: NULL pointer dereference in pci_write() in hw/acpi/pcihp.c (CVE-2021-4158)

• QEMU: block: fdc: null pointer dereference may lead to guest crash (CVE-2021-20196)

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 NULL pointer dereference flaw was found in the floppy disk emulator of QEMU. This issue occurs while processing read/write ioport commands if the selected floppy drive is not initialized with a block device. This flaw allows a privileged guest user to crash the QEMU process on the host, resulting in a denial of service. The highest threat from this vulnerability is to system availability.

Kernel-based Virtual Machine (KVM) offers a full virtualization solution for Linux on numerous hardware platforms. The virt:rhel module contains packages which provide user-space components used to run virtual machines using KVM. The packages also provide APIs for managing and interacting with the virtualized systems.

The following packages have been upgraded to a later upstream version: qemu-kvm (6.2.0), libvirt (8.0.0), libvirt-python (8.0.0), perl-Sys-Virt (8.0.0), seabios (1.15.0), libtpms (0.9.1). (BZ#1997410, BZ#2012802, BZ#2012806, BZ#2012813, BZ#2018392, BZ#2027716, BZ#2029355)

Security Fix(es):

• QEMU: virtio-net: heap use-after-free in virtio_net_receive_rcu (CVE-2021-3748)

• ntfs-3g: Out-of-bounds heap buffer access in ntfs_get_attribute_value() due to incorrect check of bytes_in_use value in MFT records (CVE-2021-33285)

• ntfs-3g: Heap buffer overflow triggered by a specially crafted Unicode string (CVE-2021-33286)

• ntfs-3g: Heap buffer overflow in ntfs_attr_pread_i() triggered by specially crafted NTFS attributes (CVE-2021-33287)

• ntfs-3g: Heap buffer overflow triggered by a specially crafted MFT section (CVE-2021-33289)

• ntfs-3g: Heap buffer overflow triggered by a specially crafted NTFS inode pathname (CVE-2021-35266)

• ntfs-3g: Stack buffer overflow triggered when correcting differences between MFT and MFTMirror sections (CVE-2021-35267)

• ntfs-3g: Heap buffer overflow in ntfs_inode_real_open() triggered by a specially crafted NTFS inode (CVE-2021-35268)

• ntfs-3g: Heap buffer overflow in ntfs_attr_setup_flag() triggered by a specially crafted NTFS attribute from MFT (CVE-2021-35269)

• ntfs-3g: NULL pointer dereference in ntfs_extent_inode_open() (CVE-2021-39251)

• ntfs-3g: Out-of-bounds read in ntfs_ie_lookup() (CVE-2021-39252)

• ntfs-3g: Out-of-bounds read in ntfs_runlists_merge_i() (CVE-2021-39253)

• ntfs-3g: Integer overflow in memmove() leading to heap buffer overflow in ntfs_attr_record_resize() (CVE-2021-39254)

• ntfs-3g: Out-of-bounds read ntfs_attr_find_in_attrdef() triggered by an invalid attribute (CVE-2021-39255)

• ntfs-3g: Heap buffer overflow in ntfs_inode_lookup_by_name() (CVE-2021-39256)

• ntfs-3g: Endless recursion from ntfs_attr_pwrite() triggered by an unallocated bitmap (CVE-2021-39257)

• ntfs-3g: Out-of-bounds reads in ntfs_attr_find() and ntfs_external_attr_find() (CVE-2021-39258)

• ntfs-3g: Out-of-bounds access in ntfs_inode_lookup_by_name() caused by an unsanitized attribute length (CVE-2021-39259)

• ntfs-3g: Out-of-bounds access in ntfs_inode_sync_standard_information() (CVE-2021-39260)

• ntfs-3g: Heap buffer overflow in ntfs_compressed_pwrite() (CVE-2021-39261)

• ntfs-3g: Out-of-bounds access in ntfs_decompress() (CVE-2021-39262)

• ntfs-3g: Heap buffer overflow in ntfs_get_attribute_value() caused by an unsanitized attribute (CVE-2021-39263)

• libnbd: nbdcopy: missing error handling may create corrupted destination image (CVE-2022-0485)

• hivex: stack overflow due to recursive call of _get_children() (CVE-2021-3622)

• nbdkit: NBD_OPT_STRUCTURED_REPLY injection on STARTTLS (CVE-2021-3716)

• libvirt: segmentation fault during VM shutdown can lead to vdsm hang (CVE-2021-3975)

• QEMU: NULL pointer dereference in mirror_wait_on_conflicts() in block/mirror.c (CVE-2021-4145)

• QEMU: NULL pointer dereference in pci_write() in hw/acpi/pcihp.c (CVE-2021-4158)

• QEMU: block: fdc: null pointer dereference may lead to guest crash (CVE-2021-20196)

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 AlmaLinux Release Notes linked from the References section.

This update for qemu fixes the following issues:

• CVE-2021-20196: Fixed null pointer dereference that may lead to guest crash (bsc#1181361).

This update for qemu fixes the following issues:

• CVE-2020-13253: Fixed an OOB access that could crash the guest resulting in DoS (bsc#1172033)
• CVE-2021-20196: Fixed null pointer dereference that may lead to guest crash (bsc#1181361).

This update for qemu fixes the following issues:

• CVE-2021-20196: Fixed null pointer dereference that may lead to guest crash (bsc#1181361).

This update for qemu fixes the following issues:

• CVE-2020-13253: Fixed an OOB access that could crash the guest resulting in DoS (bsc#1172033)
• CVE-2021-20196: Fixed null pointer dereference that may lead to guest crash (bsc#1181361).

This update for qemu fixes the following issues:

• CVE-2020-13253: Fixed an OOB access that could crash the guest resulting in DoS (bsc#1172033)
• CVE-2021-20196: Fixed null pointer dereference that may lead to guest crash (bsc#1181361).

This update for qemu fixes the following issues:

• CVE-2021-20196: Fixed a denial of service in the floppy disk emulator (bsc#1181361).
• CVE-2021-3930: Fixed a potential denial of service in the emulated SCSI device (bsc#1192525).

Non-security fixes:

• Fixed a kernel data corruption via a long kernel boot cmdline (bsc#1196737).

Gaoning Pan discovered that QEMU incorrectly handled the floppy disk emulator. An attacker inside the guest could use this issue to cause QEMU to crash, resulting in a denial of service. (CVE-2021-20196)

Gaoning Pan discovered that the QEMU vmxnet3 NIC emulator incorrectly handled certain values. An attacker inside the guest could use this issue to cause QEMU to crash, resulting in a denial of service. (CVE-2021-20203)

It was discovered that the QEMU vhost-user GPU device contained several security issues. An attacker inside the guest could use these issues to cause QEMU to crash, resulting in a denial of service, leak sensitive information, or possibly execute arbitrary code. This issue only affected Ubuntu 21.10. (CVE-2021-3544, CVE-2021-3545, CVE-2021-3546)

It was discovered that QEMU incorrectly handled bulk transfers from SPICE clients. A remote attacker could use this issue to cause QEMU to crash, resulting in a denial of service, or possibly execute arbitrary code. (CVE-2021-3682)

It was discovered that the QEMU UAS device emulation incorrectly handled certain stream numbers. An attacker inside the guest could use this issue to cause QEMU to crash, resulting in a denial of service, or possibly execute arbitrary code. This issue only affected Ubuntu 21.10. (CVE-2021-3713)

It was discovered that the QEMU virtio-net device incorrectly handled certain buffer addresses. An attacker inside the guest could use this issue to cause QEMU to crash, resulting in a denial of service, or possibly execute arbitrary code. (CVE-2021-3748)

It was discovered that the QEMU SCSI device emulation incorrectly handled certain MODE SELECT commands. An attacker inside the guest could possibly use this issue to cause QEMU to crash, resulting in a denial of service. (CVE-2021-3930)

It was discovered that the QEMU ACPI logic incorrectly handled certain values. An attacker inside the guest could possibly use this issue to cause QEMU to crash, resulting in a denial of service. This issue only affected Ubuntu 21.10. (CVE-2021-4158)

Jietao Xiao, Jinku Li, Wenbo Shen, and Nanzi Yang discovered that the QEMU virtiofsd device incorrectly handled permissions when creating files. An attacker inside the guest could use this issue to create files inside the directory shared by virtiofs with unintended permissions, possibly allowing privilege escalation. This issue only affected Ubuntu 21.10. (CVE-2022-0358)