CVE-2018-12904

In arch/x86/kvm/vmx.c in the Linux kernel before 4.17.2, when nested virtualization is used, local attackers could cause L1 KVM guests to VMEXIT, potentially allowing privilege escalations and denial of service attacks due to lack of checking of CPL.

This kernel update is based on the upstream 4.14.50 and fixes at least the following security issues:

In the function sbusfb_ioctl_helper() in drivers/video/fbdev/sbuslib.c in the Linux kernel through 4.15, an integer signedness error allows arbitrary information leakage for the FBIOPUTCMAP_SPARC and FBIOGETCMAP_SPARC commands (CVE-2018-6412).

The kvm functions that were used in the emulation of fxrstor, fxsave, sgdt and sidt were originally meant for task switching, and as such they did not check privilege levels. This allowed guest userspace to guest kernel write (CVE-2018-10853).

In arch/x86/kvm/vmx.c in the Linux kernel before 4.17.2, when nested virtualization is used, local attackers could cause L1 KVM guests to VMEXIT, potentially allowing privilege escalations and denial of service attacks due to lack of checking of CPL (CVE-2018-12904).

WireGuard has been updated to 0.0.20180613.

For other fixes in this update, see the referenced changelogs.

This kernel-tmb update is based on the upstream 4.14.62 and fixes at least the following security issues:

kernel KVM before versions kernel 4.16, kernel 4.16-rc7, kernel 4.17-rc1, kernel 4.17-rc2 and kernel 4.17-rc3 is vulnerable to a flaw in the way the Linux kernel's KVM hypervisor handled exceptions delivered after a stack switch operation via Mov SS or Pop SS instructions. During the stack switch operation, the processor did not deliver interrupts and exceptions, rather they are delivered once the first instruction after the stack switch is executed. An unprivileged KVM guest user could use this flaw to crash the guest or, potentially, escalate their privileges in the guest (CVE-2018-1087).

Linux kernel vhost since version 4.8 does not properly initialize memory in messages passed between virtual guests and the host operating system in the vhost/vhost.c:vhost_new_msg() function. This can allow local privileged users to read some kernel memory contents when reading from the /dev/vhost-net device file (CVE-2018-1118).

Security researchers from FICORA have identified a remote denial of service attack against the Linux kernel caused by inefficient implementation of TCP segment reassembly, named "SegmentSmack". A remote attacker could consume a lot of CPU resources in the kernel networking stack with just a low bandwidth or single host attack by using lots of small TCP segments packets. Usually large botnets are needed for similar effect. The rate needed for this denial of service attack to be effective is several magnitudes lower than the usual packet processing capability of the machine, as the attack exploits worst case behaviour of existing algorithms (CVE-2018-5390). In the function sbusfb_ioctl_helper() in drivers/video/fbdev/sbuslib.c in the Linux kernel through 4.15, an integer signedness error allows arbitrary information leakage for the FBIOPUTCMAP_SPARC and FBIOGETCMAP_SPARC commands (CVE-2018-6412).

In some circumstances, some operating systems or hypervisors may not expect or properly handle an Intel architecture hardware debug exception. The error appears to be due to developer interpretation of existing documentation for certain Intel architecture interrupt/exception instructions, namely MOV SS and POP SS. An authenticated attacker may be able to read sensitive data in memory or control low-level operating system functions (CVE-2018-8897).

Linux kernel is vulnerable to a heap-based buffer overflow in the fs/ext4/xattr.c:ext4_xattr_set_entry() function. An attacker could exploit this by operating on a mounted crafted ext4 image (CVE-2018-10840).

The kvm functions that were used in the emulation of fxrstor, fxsave, sgdt and sidt were originally meant for task switching, and as such they did not check privilege levels. This allowed guest userspace to guest kernel write (CVE-2018-10853).

A flaw was found in Linux kernel ext4 File System. A use-after-free in ext4_ext_remove_space() when mounting and operating a crafted ext4 image (CVE-2018-10876).

Linux kernel ext4 filesystem is vulnerable to an out-of-bound access in the ext4_ext_drop_refs() function when operating on a crafted ext4 filesystem image (CVE-2018-10877).

A flaw was found in Linux kernel ext4 filesystem. A local user can cause a use-after-free in ext4_xattr_set_entry function and so a denial of service or possibly unspecified other impact by when renaming a file in a crafted ext4 filesystem image (CVE-2018-10879).

A flaw was found in Linux kernel ext4 filesystem code. A stack-out-of-bounds write in ext4_update_inline_data() is possible when mounting and writing to a crafted ext4 image. An attacker could use this to cause a system crash and a denial of service (CVE-2018-10880).

A flaw was found in Linux kernel ext4 filesystem. A local user can cause an out-of-bound access in ext4_get_group_info function and so a denial of service and a system crash by mounting and operating on a crafted ext4 filesystem image (CVE-2018-10881).

A flaw was…

This kernel-linus update is based on the upstream 4.14.62 and fixes at least the following security issues:

kernel KVM before versions kernel 4.16, kernel 4.16-rc7, kernel 4.17-rc1, kernel 4.17-rc2 and kernel 4.17-rc3 is vulnerable to a flaw in the way the Linux kernel's KVM hypervisor handled exceptions delivered after a stack switch operation via Mov SS or Pop SS instructions. During the stack switch operation, the processor did not deliver interrupts and exceptions, rather they are delivered once the first instruction after the stack switch is executed. An unprivileged KVM guest user could use this flaw to crash the guest or, potentially, escalate their privileges in the guest (CVE-2018-1087).

Linux kernel vhost since version 4.8 does not properly initialize memory in messages passed between virtual guests and the host operating system in the vhost/vhost.c:vhost_new_msg() function. This can allow local privileged users to read some kernel memory contents when reading from the /dev/vhost-net device file (CVE-2018-1118).

Security researchers from FICORA have identified a remote denial of service attack against the Linux kernel caused by inefficient implementation of TCP segment reassembly, named "SegmentSmack". A remote attacker could consume a lot of CPU resources in the kernel networking stack with just a low bandwidth or single host attack by using lots of small TCP segments packets. Usually large botnets are needed for similar effect. The rate needed for this denial of service attack to be effective is several magnitudes lower than the usual packet processing capability of the machine, as the attack exploits worst case behaviour of existing algorithms (CVE-2018-5390). In the function sbusfb_ioctl_helper() in drivers/video/fbdev/sbuslib.c in the Linux kernel through 4.15, an integer signedness error allows arbitrary information leakage for the FBIOPUTCMAP_SPARC and FBIOGETCMAP_SPARC commands (CVE-2018-6412).

In some circumstances, some operating systems or hypervisors may not expect or properly handle an Intel architecture hardware debug exception. The error appears to be due to developer interpretation of existing documentation for certain Intel architecture interrupt/exception instructions, namely MOV SS and POP SS. An authenticated attacker may be able to read sensitive data in memory or control low-level operating system functions (CVE-2018-8897).

Linux kernel is vulnerable to a heap-based buffer overflow in the fs/ext4/xattr.c:ext4_xattr_set_entry() function. An attacker could exploit this by operating on a mounted crafted ext4 image (CVE-2018-10840).

The kvm functions that were used in the emulation of fxrstor, fxsave, sgdt and sidt were originally meant for task switching, and as such they did not check privilege levels. This allowed guest userspace to guest kernel write (CVE-2018-10853).

A flaw was found in Linux kernel ext4 File System. A use-after-free in ext4_ext_remove_space() when mounting and operating a crafted ext4 image (CVE-2018-10876).

Linux kernel ext4 filesystem is vulnerable to an out-of-bound access in the ext4_ext_drop_refs() function when operating on a crafted ext4 filesystem image (CVE-2018-10877).

A flaw was found in Linux kernel ext4 filesystem. A local user can cause a use-after-free in ext4_xattr_set_entry function and so a denial of service or possibly unspecified other impact by when renaming a file in a crafted ext4 filesystem image (CVE-2018-10879).

A flaw was found in Linux kernel ext4 filesystem code. A stack-out-of-bounds write in ext4_update_inline_data() is possible when mounting and writing to a crafted ext4 image. An attacker could use this to cause a system crash and a denial of service (CVE-2018-10880).

A flaw was found in Linux kernel ext4 filesystem. A local user can cause an out-of-bound access in ext4_get_group_info function and so a denial of service and a system crash by mounting and operating on a crafted ext4 filesystem image (CVE-2018-10881).

A flaw was…

This update for the Linux Kernel 4.12.14-23 fixes several issues.

The following security issues were fixed:

• CVE-2018-5390: Linux kernel versions 4.9+ can be forced to make very expensive calls to tcp_collapse_ofo_queue() and tcp_prune_ofo_queue() for every incoming packet which can lead to a denial of service (bsc#1102682).
• CVE-2018-3646: Local attackers in virtualized guest systems could use speculative code patterns on hyperthreaded processors to read data present in the L1 Datacache used by other hyperthreads on the same CPU core, potentially leaking sensitive data, even from other virtual machines or the host system (bsc#1099306).
• CVE-2017-18344: The timer_create syscall implementation in kernel/time/posix-timers.c didn't properly validate the sigevent->sigev_notify field, which lead to out-of-bounds access in the show_timer function (called when /proc/$PID/timers is read). This allowed userspace applications to read arbitrary kernel memory (on a kernel built with CONFIG_POSIX_TIMERS and CONFIG_CHECKPOINT_RESTORE) (bsc#1103203). before 4.14.8
• CVE-2018-12904: In arch/x86/kvm/vmx.c local attackers could cause L1 KVM guests to VMEXIT, potentially allowing privilege escalations and denial of service attacks due to lack of checking of CPL (bsc#1099258).
• CVE-2018-10853: A flaw was found in kvm. In which certain instructions such as sgdt/sidt call segmented_write_std didn't propagate access correctly. As such, during userspace induced exception, the guest can incorrectly assume that the exception happened in the kernel and panic. (bsc#1097108).

It was discovered that, when attempting to handle an out-of-memory situation, a null pointer dereference could be triggered in the Linux kernel in some circumstances. A local attacker could use this to cause a denial of service (system crash). (CVE-2018-1000200)

Wen Xu discovered that the XFS filesystem implementation in the Linux kernel did not properly validate meta-data information. An attacker could use this to construct a malicious xfs image that, when mounted, could cause a denial of service (system crash). (CVE-2018-10323)

Wen Xu discovered that the XFS filesystem implementation in the Linux kernel did not properly validate xattr information. An attacker could use this to construct a malicious xfs image that, when mounted, could cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2018-10840)

Wen Xu discovered that the ext4 filesystem implementation in the Linux kernel did not properly keep meta-data information consistent in some situations. An attacker could use this to construct a malicious ext4 image that, when mounted, could cause a denial of service (system crash). (CVE-2018-10881)

Wen Xu discovered that the ext4 filesystem implementation in the Linux kernel did not properly handle corrupted meta data in some situations. An attacker could use this to specially craft an ext4 filesystem that caused a denial of service (system crash) when mounted. (CVE-2018-1093)

Jann Horn discovered that the Linux kernel's implementation of random seed data reported that it was in a ready state before it had gathered sufficient entropy. An attacker could use this to expose sensitive information. (CVE-2018-1108)

It was discovered that the procfs filesystem did not properly handle processes mapping some memory elements onto files. A local attacker could use this to block utilities that examine the procfs filesystem to report operating system state, such as ps(1). (CVE-2018-1120)

Jann Horn discovered that the ext4 filesystem implementation in the Linux kernel did not properly keep xattr information consistent in some situations. An attacker could use this to construct a malicious ext4 image that, when mounted, could cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2018-11412)

Piotr Gabriel Kosinski and Daniel Shapira discovered a stack-based buffer overflow in the CDROM driver implementation of the Linux kernel. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2018-11506)

Shankara Pailoor discovered that a race condition existed in the socket handling code in the Linux kernel. A local attacker could use this to cause a denial of service (system crash). (CVE-2018-12232)

Shankara Pailoor discovered that the JFS filesystem implementation in the Linux kernel contained a buffer overflow when handling extended attributes. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2018-12233)

Felix Wilhelm discovered that the KVM implementation in the Linux kernel did not properly perform permission checks in some situations when nested virtualization is used. An attacker in a guest VM could possibly use this to escape into an outer VM or the host OS. (CVE-2018-12904)

Wen Xu discovered that the XFS filesystem implementation in the Linux kernel did not properly handle an error condition with a corrupted xfs image. An attacker could use this to construct a malicious xfs image that, when mounted, could cause a denial of service (system crash). (CVE-2018-13094)

It was discovered that the Linux kernel did not properly handle setgid file creation when performed by a non-member of the group. A local attacker could use this to gain elevated privileges. (CVE-2018-13405)

Silvio Cesare discovered that the generic VESA frame buffer driver in the Linux kernel contained an integer overflow. A local attacker could use this to cause a denial of service…

USN-3752-1 fixed vulnerabilities in the Linux kernel for Ubuntu 18.04 LTS. This update provides the corresponding updates for the Linux Hardware Enablement (HWE) kernel from Ubuntu 18.04 LTS for Ubuntu 16.04 LTS.

It was discovered that, when attempting to handle an out-of-memory situation, a null pointer dereference could be triggered in the Linux kernel in some circumstances. A local attacker could use this to cause a denial of service (system crash). (CVE-2018-1000200)

Wen Xu discovered that the XFS filesystem implementation in the Linux kernel did not properly validate meta-data information. An attacker could use this to construct a malicious xfs image that, when mounted, could cause a denial of service (system crash). (CVE-2018-10323)

Wen Xu discovered that the XFS filesystem implementation in the Linux kernel did not properly validate xattr information. An attacker could use this to construct a malicious xfs image that, when mounted, could cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2018-10840)

Wen Xu discovered that the ext4 filesystem implementation in the Linux kernel did not properly keep meta-data information consistent in some situations. An attacker could use this to construct a malicious ext4 image that, when mounted, could cause a denial of service (system crash). (CVE-2018-10881)

Wen Xu discovered that the ext4 filesystem implementation in the Linux kernel did not properly handle corrupted meta data in some situations. An attacker could use this to specially craft an ext4 filesystem that caused a denial of service (system crash) when mounted. (CVE-2018-1093)

Jann Horn discovered that the Linux kernel's implementation of random seed data reported that it was in a ready state before it had gathered sufficient entropy. An attacker could use this to expose sensitive information. (CVE-2018-1108)

It was discovered that the procfs filesystem did not properly handle processes mapping some memory elements onto files. A local attacker could use this to block utilities that examine the procfs filesystem to report operating system state, such as ps(1). (CVE-2018-1120)

Jann Horn discovered that the ext4 filesystem implementation in the Linux kernel did not properly keep xattr information consistent in some situations. An attacker could use this to construct a malicious ext4 image that, when mounted, could cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2018-11412)

Piotr Gabriel Kosinski and Daniel Shapira discovered a stack-based buffer overflow in the CDROM driver implementation of the Linux kernel. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2018-11506)

Shankara Pailoor discovered that a race condition existed in the socket handling code in the Linux kernel. A local attacker could use this to cause a denial of service (system crash). (CVE-2018-12232)

Shankara Pailoor discovered that the JFS filesystem implementation in the Linux kernel contained a buffer overflow when handling extended attributes. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2018-12233)

Felix Wilhelm discovered that the KVM implementation in the Linux kernel did not properly perform permission checks in some situations when nested virtualization is used. An attacker in a guest VM could possibly use this to escape into an outer VM or the host OS. (CVE-2018-12904)

Wen Xu discovered that the XFS filesystem implementation in the Linux kernel did not properly handle an error condition with a corrupted xfs image. An attacker could use this to construct a malicious xfs image that, when mounted, could cause a denial of service (system crash). (CVE-2018-13094)

It was discovered that the Linux kernel did not properly handle setgid file creation when performed by a non-member of the group. A local attacker could use this to gain elevated…

It was discovered that, when attempting to handle an out-of-memory situation, a null pointer dereference could be triggered in the Linux kernel in some circumstances. A local attacker could use this to cause a denial of service (system crash). (CVE-2018-1000200)

Wen Xu discovered that the XFS filesystem implementation in the Linux kernel did not properly validate meta-data information. An attacker could use this to construct a malicious xfs image that, when mounted, could cause a denial of service (system crash). (CVE-2018-10323)

Wen Xu discovered that the XFS filesystem implementation in the Linux kernel did not properly validate xattr information. An attacker could use this to construct a malicious xfs image that, when mounted, could cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2018-10840)

Wen Xu discovered that the ext4 filesystem implementation in the Linux kernel did not properly keep meta-data information consistent in some situations. An attacker could use this to construct a malicious ext4 image that, when mounted, could cause a denial of service (system crash). (CVE-2018-10881)

Wen Xu discovered that the ext4 filesystem implementation in the Linux kernel did not properly handle corrupted meta data in some situations. An attacker could use this to specially craft an ext4 filesystem that caused a denial of service (system crash) when mounted. (CVE-2018-1093)

Jann Horn discovered that the Linux kernel's implementation of random seed data reported that it was in a ready state before it had gathered sufficient entropy. An attacker could use this to expose sensitive information. (CVE-2018-1108)

It was discovered that the procfs filesystem did not properly handle processes mapping some memory elements onto files. A local attacker could use this to block utilities that examine the procfs filesystem to report operating system state, such as ps(1). (CVE-2018-1120)

Jann Horn discovered that the ext4 filesystem implementation in the Linux kernel did not properly keep xattr information consistent in some situations. An attacker could use this to construct a malicious ext4 image that, when mounted, could cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2018-11412)

Piotr Gabriel Kosinski and Daniel Shapira discovered a stack-based buffer overflow in the CDROM driver implementation of the Linux kernel. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2018-11506)

Shankara Pailoor discovered that a race condition existed in the socket handling code in the Linux kernel. A local attacker could use this to cause a denial of service (system crash). (CVE-2018-12232)

Shankara Pailoor discovered that the JFS filesystem implementation in the Linux kernel contained a buffer overflow when handling extended attributes. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2018-12233)

Felix Wilhelm discovered that the KVM implementation in the Linux kernel did not properly perform permission checks in some situations when nested virtualization is used. An attacker in a guest VM could possibly use this to escape into an outer VM or the host OS. (CVE-2018-12904)

Wen Xu discovered that the XFS filesystem implementation in the Linux kernel did not properly handle an error condition with a corrupted xfs image. An attacker could use this to construct a malicious xfs image that, when mounted, could cause a denial of service (system crash). (CVE-2018-13094)

It was discovered that the Linux kernel did not properly handle setgid file creation when performed by a non-member of the group. A local attacker could use this to gain elevated privileges. (CVE-2018-13405)

Silvio Cesare discovered that the generic VESA frame buffer driver in the Linux kernel contained an integer overflow. A local attacker could use this to cause a denial of service…