CVE-2018-18397

The userfaultfd implementation in the Linux kernel before 4.19.7 mishandles access control for certain UFFDIO_ ioctl calls, as demonstrated by allowing local users to write data into holes in a tmpfs file (if the user has read-only access to that file, and that file contains holes), related to fs/userfaultfd.c and mm/userfaultfd.c.

This kernel update is based on the upstream 4.14.89 and fixes at least the following security issues:

Cross-hyperthread Spectre v2 mitigation is now provided by the Single Thread Indirect Branch Predictors (STIBP) support. Note that STIBP also requires the functionality be supported by the Intel microcode in use.

It was found that cephx authentication protocol did not verify ceph clients correctly and was vulnerable to replay attack. Any attacker having access to ceph cluster network who is able to sniff packets on network can use this vulnerability to authenticate with ceph service and perform actions allowed by ceph service (CVE-2018-1128).

A flaw was found in the way signature calculation was handled by cephx authentication protocol. An attacker having access to ceph cluster network who is able to alter the message payload was able to bypass signature checks done by cephx protocol (CVE-2018-1129).

A flaw was found in the Linux Kernel where an attacker may be able to have an uncontrolled read to kernel-memory from within a vm guest. A race condition between connect() and close() function may allow an attacker using the AF_VSOCK protocol to gather a 4 byte information leak or possibly intercept or corrupt AF_VSOCK messages destined to other clients (CVE-2018-14625).

A security flaw was found in the Linux kernel in a way that the cleancache subsystem clears an inode after the final file truncation (removal). The new file created with the same inode may contain leftover pages from cleancache and the old file data instead of the new one (CVE-2018-16862).

The userfaultfd implementation in the Linux kernel before 4.19.7 mishandles access control for certain UFFDIO_ ioctl calls, as demonstrated by allowing local users to write data into holes in a tmpfs file (if the user has read-only access to that file, and that file contains holes) (CVE-2018-18397).

In the Linux kernel through 4.19.6, a local user could exploit a use-after-free in the ALSA driver by supplying a malicious USB Sound device (with zero interfaces) (CVE-2018-19824).

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

This kernel-linus update is based on the upstream 4.14.100 and fixes at least the following security issues:

Cross-hyperthread Spectre v2 mitigation is now provided by the Single Thread Indirect Branch Predictors (STIBP) support. Note that STIBP also requires the functionality be supported by the Intel microcode in use.

It was found that cephx authentication protocol did not verify ceph clients correctly and was vulnerable to replay attack. Any attacker having access to ceph cluster network who is able to sniff packets on network can use this vulnerability to authenticate with ceph service and perform actions allowed by ceph service (CVE-2018-1128).

A flaw was found in the way signature calculation was handled by cephx authentication protocol. An attacker having access to ceph cluster network who is able to alter the message payload was able to bypass signature checks done by cephx protocol (CVE-2018-1129).

A flaw was found in the Linux Kernel where an attacker may be able to have an uncontrolled read to kernel-memory from within a vm guest. A race condition between connect() and close() function may allow an attacker using the AF_VSOCK protocol to gather a 4 byte information leak or possibly intercept or corrupt AF_VSOCK messages destined to other clients (CVE-2018-14625).

A security flaw was found in the Linux kernel in a way that the cleancache subsystem clears an inode after the final file truncation (removal). The new file created with the same inode may contain leftover pages from cleancache and the old file data instead of the new one (CVE-2018-16862).

A use-after-free issue was found in the way the Linux kernel's KVM hypervisor processed posted interrupts when nested(=1) virtualization is enabled. In nested_get_vmcs12_pages(), in case of an error while processing posted interrupt address, it unmaps the 'pi_desc_page' without resetting 'pi_desc' descriptor address, which is later used in pi_test_and_clear_on(). A guest user/process could use this flaw to crash the host kernel resulting in DoS or potentially gain privileged access to a system (CVE-2018-16882).

A flaw was found in the Linux kernel's NFS41+ subsystem. NFS41+ shares mounted in different network namespaces at the same time can make bc_svc_process() use wrong back-channel IDs and cause a use-after-free vulnerability. Thus a malicious container user can cause a host kernel memory corruption and a system panic. Due to the nature of the flaw, privilege escalation cannot be fully ruled out (CVE-2018-16884).

The userfaultfd implementation in the Linux kernel before 4.19.7 mishandles access control for certain UFFDIO_ ioctl calls, as demonstrated by allowing local users to write data into holes in a tmpfs file (if the user has read-only access to that file, and that file contains holes) (CVE-2018-18397).

In the Linux kernel through 4.19.6, a local user could exploit a use-after-free in the ALSA driver by supplying a malicious USB Sound device (with zero interfaces) (CVE-2018-19824).

A flaw was found in the Linux kernel in the function hso_probe() which reads if_num value from the USB device (as an u8) and uses it without a length check to index an array, resulting in an OOB memory read in hso_probe() or hso_get_config_data(). An attacker with a forged USB device and physical access to a system (needed to connect such a device) can cause a system crash and a denial of service (CVE-2018-19985).

An issue was discovered in can_can_gw_rcv in net/can/gw.c in the Linux kernel through 4.19.13. The CAN frame modification rules allow bitwise logical operations that can be also applied to the can_dlc field. Because of a missing check, the CAN drivers may write arbitrary content beyond the data registers in the CAN controller's I/O memory when processing can-gw manipulated outgoing frames. This is related to cgw_csum_xor_rel. An unprivileged user can trigger a system crash (general protection fault) (CVE-2019-3701).

A flaw was found in the Linux kernel in the…

This kernel update provides the upstream 4.14.119 that adds the kernel side mitigations for the Microarchitectural Data Sampling (MDS, also called ZombieLoad attack) vulnerabilities in Intel processors that can allow attackers to retrieve data being processed inside a CPU. To complete the mitigations new microcode is also needed, either by installing the microcode-0.20190514-1.mga6 package, or get an updated bios / uefi firmware from the motherboard vendor.

The fixed / mitigated issues are:

Modern Intel microprocessors implement hardware-level micro-optimizations to improve the performance of writing data back to CPU caches. The write operation is split into STA (STore Address) and STD (STore Data) sub-operations. These sub-operations allow the processor to hand-off address generation logic into these sub-operations for optimized writes. Both of these sub-operations write to a shared distributed processor structure called the 'processor store buffer'. As a result, an unprivileged attacker could use this flaw to read private data resident within the CPU's processor store buffer. (CVE-2018-12126)

Microprocessors use a ‘load port’ subcomponent to perform load operations from memory or IO. During a load operation, the load port receives data from the memory or IO subsystem and then provides the data to the CPU registers and operations in the CPU’s pipelines. Stale load operations results are stored in the 'load port' table until overwritten by newer operations. Certain load-port operations triggered by an attacker can be used to reveal data about previous stale requests leaking data back to the attacker via a timing side-channel. (CVE-2018-12127)

A flaw was found in the implementation of the "fill buffer", a mechanism used by modern CPUs when a cache-miss is made on L1 CPU cache. If an attacker can generate a load operation that would create a page fault, the execution will continue speculatively with incorrect data from the fill buffer while the data is fetched from higher level caches. This response time can be measured to infer data in the fill buffer. (CVE-2018-12130)

Uncacheable memory on some microprocessors utilizing speculative execution may allow an authenticated user to potentially enable information disclosure via a side channel with local access. (CVE-2019-11091)

It also fixes at least the following security issues:

Cross-hyperthread Spectre v2 mitigation is now provided by the Single Thread Indirect Branch Predictors (STIBP) support. Note that STIBP also requires the functionality be supported by the Intel microcode in use.

It was found that cephx authentication protocol did not verify ceph clients correctly and was vulnerable to replay attack. Any attacker having access to ceph cluster network who is able to sniff packets on network can use this vulnerability to authenticate with ceph service and perform actions allowed by ceph service (CVE-2018-1128).

A flaw was found in the way signature calculation was handled by cephx authentication protocol. An attacker having access to ceph cluster network who is able to alter the message payload was able to bypass signature checks done by cephx protocol (CVE-2018-1129).

A flaw was found in the Linux Kernel where an attacker may be able to have an uncontrolled read to kernel-memory from within a vm guest. A race condition between connect() and close() function may allow an attacker using the AF_VSOCK protocol to gather a 4 byte information leak or possibly intercept or corrupt AF_VSOCK messages destined to other clients (CVE-2018-14625).

A security flaw was found in the Linux kernel in a way that the cleancache subsystem clears an inode after the final file truncation (removal). The new file created with the same inode may contain leftover pages from cleancache and the old file data instead of the new one (CVE-2018-16862).

A use-after-free issue was found in the way the Linux kernel's KVM hypervisor processed posted interrupts when nested(=1) virtualization…

The openSUSE Leap 15.0 kernel was updated to receive various security and bugfixes.

The following security bugs were fixed:

• CVE-2018-19407: The vcpu_scan_ioapic function in arch/x86/kvm/x86.c allowed local users to cause a denial of service (NULL pointer dereference and BUG) via crafted system calls that reach a situation where ioapic is uninitialized (bnc#1116841).
• CVE-2018-14625: An attacker might have bene able to have an uncontrolled read to kernel-memory from within a vm guest. A race condition between connect() and close() function may allow an attacker using the AF_VSOCK protocol to gather a 4 byte information leak or possibly intercept or corrupt AF_VSOCK messages destined to other clients (bnc#1106615).
• CVE-2018-19985: The function hso_probe read if_num from the USB device (as an u8) and used it without a length check to index an array, resulting in an OOB memory read in hso_probe or hso_get_config_data that could be used by local attackers (bsc#1120743).
• CVE-2018-16884: NFS41+ shares mounted in different network namespaces at the same time can make bc_svc_process() use wrong back-channel IDs and cause a use-after-free vulnerability. Thus a malicious container user can cause a host kernel memory corruption and a system panic. Due to the nature of the flaw, privilege escalation cannot be fully ruled out (bnc#1119946).
• CVE-2018-20169: The USB subsystem mishandled size checks during the reading of an extra descriptor, related to __usb_get_extra_descriptor in drivers/usb/core/usb.c (bnc#1119714).
• CVE-2018-18397: The userfaultfd implementation mishandled access control for certain UFFDIO_ ioctl calls, as demonstrated by allowing local users to write data into holes in a tmpfs file (if the user has read-only access to that file, and that file contains holes), related to fs/userfaultfd.c and mm/userfaultfd.c (bnc#1117656).
• CVE-2018-12232: In net/socket.c there was a race condition between fchownat and close in cases where they target the same socket file descriptor, related to the sock_close and sockfs_setattr functions. fchownat did not increment the file descriptor reference count, which allowed close to set the socket to NULL during fchownat's execution, leading to a NULL pointer dereference and system crash (bnc#1097593).
• CVE-2018-9568: In sk_clone_lock of sock.c, there is a possible memory corruption due to type confusion. This could lead to local escalation of privilege with no additional execution privileges needed. User interaction is not needed for exploitation. (bnc#1118319).
• CVE-2018-16862: A security flaw was found in the way that the cleancache subsystem clears an inode after the final file truncation (removal). The new file created with the same inode may contain leftover pages from cleancache and the old file data instead of the new one (bnc#1117186).
• CVE-2018-19854: An issue was discovered in the crypto_report_one() and related functions in crypto/crypto_user.c (the crypto user configuration API) do not fully initialize structures that are copied to userspace, potentially leaking sensitive memory to user programs. NOTE: this is a CVE-2013-2547 regression but with easier exploitability because the attacker did not need a capability (however, the system must have the CONFIG_CRYPTO_USER kconfig option) (bnc#1118428).
• CVE-2018-19824: A local user could exploit a use-after-free in the ALSA driver by supplying a malicious USB Sound device (with zero interfaces) that is mishandled in usb_audio_probe in sound/usb/card.c (bnc#1118152).

The following non-security bugs were fixed:

• ACPI / CPPC: Check for valid PCC subspace only if PCC is used (bsc#1117115).
• ACPI / CPPC: Update all pr_(debug/err) messages to log the susbspace id (bsc#1117115).
• aio: fix spectre gadget in lookup_ioctx (bsc#1120594).
• alsa: cs46xx: Potential NULL dereference in probe (bsc#1051510).
• alsa: emu10k1: Fix potential Spectre v1 vulnerabilities (bsc#1051510).
• alsa: emux: Fix potential Spectre v1…

The SUSE Linux Enterprise 15 kernel for Azure was updated to receive various security and bugfixes.

The following security bugs were fixed:

• CVE-2018-9568: In sk_clone_lock of sock.c, there is a possible memory corruption due to type confusion. This could lead to local escalation of privilege with no additional execution privileges needed. User interaction is not needed for exploitation. (bnc#1118319).
• CVE-2018-12232: In net/socket.c there is a race condition between fchownat and close in cases where they target the same socket file descriptor, related to the sock_close and sockfs_setattr functions. fchownat did not increment the file descriptor reference count, which allowed close to set the socket to NULL during fchownat's execution, leading to a NULL pointer dereference and system crash (bnc#1097593).
• CVE-2018-14625: A flaw was found where an attacker may be able to have an uncontrolled read to kernel-memory from within a vm guest. A race condition between connect() and close() function may allow an attacker using the AF_VSOCK protocol to gather a 4 byte information leak or possibly intercept or corrupt AF_VSOCK messages destined to other clients (bnc#1106615).
• CVE-2018-16862: A security flaw was found in the way that the cleancache subsystem clears an inode after the final file truncation (removal). The new file created with the same inode may contain leftover pages from cleancache and the old file data instead of the new one (bnc#1117186).
• CVE-2018-16884: NFS41+ shares mounted in different network namespaces at the same time can make bc_svc_process() use wrong back-channel IDs and cause a use-after-free vulnerability. Thus a malicious container user can cause a host kernel memory corruption and a system panic. Due to the nature of the flaw, privilege escalation cannot be fully ruled out (bnc#1119946).
• CVE-2018-18281: The mremap() syscall performs TLB flushes after dropping pagetable locks. If a syscall such as ftruncate() removes entries from the pagetables of a task that is in the middle of mremap(), a stale TLB entry can remain for a short time that permits access to a physical page after it has been released back to the page allocator and reused. (bnc#1113769).
• CVE-2018-18397: The userfaultfd implementation mishandled access control for certain UFFDIO_ ioctl calls, as demonstrated by allowing local users to write data into holes in a tmpfs file (if the user has read-only access to that file, and that file contains holes), related to fs/userfaultfd.c and mm/userfaultfd.c (bnc#1117656).
• CVE-2018-19407: The vcpu_scan_ioapic function in arch/x86/kvm/x86.c allowed local users to cause a denial of service (NULL pointer dereference and BUG) via crafted system calls that reach a situation where ioapic is uninitialized (bnc#1116841).
• CVE-2018-19824: A local user could exploit a use-after-free in the ALSA driver by supplying a malicious USB Sound device (with zero interfaces) that is mishandled in usb_audio_probe in sound/usb/card.c (bnc#1118152).
• CVE-2018-19854: An issue was discovered in the crypto_report_one() and related functions in crypto/crypto_user.c (the crypto user configuration API) do not fully initialize structures that are copied to userspace, potentially leaking sensitive memory to user programs. NOTE: this is a CVE-2013-2547 regression but with easier exploitability because the attacker did not need a capability (however, the system must have the CONFIG_CRYPTO_USER kconfig option) (bnc#1118428).
• CVE-2018-19985: The function hso_probe read if_num from the USB device (as an u8) and used it without a length check to index an array, resulting in an OOB memory read in hso_probe or hso_get_config_data that could be used by local attackers (bnc#1120743).
• CVE-2018-20169: The USB subsystem mishandled size checks during the reading of an extra descriptor, related to __usb_get_extra_descriptor in drivers/usb/core/usb.c (bnc#1119714).

The following non-security bugs were fixed:

• ACPI/APEI: Handle…

The SUSE Linux Enterprise 12 SP4 kernel was updated to receive various security and bugfixes.

The following security bugs were fixed:

• CVE-2018-9568: In sk_clone_lock of sock.c, there is a possible memory corruption due to type confusion. This could lead to local escalation of privilege with no additional execution privileges needed. User interaction is not needed for exploitation. (bnc#1118319).
• CVE-2018-12232: In net/socket.c in the there is a race condition between fchownat and close in cases where they target the same socket file descriptor, related to the sock_close and sockfs_setattr functions. fchownat did not increment the file descriptor reference count, which allowed close to set the socket to NULL during fchownat's execution, leading to a NULL pointer dereference and system crash (bnc#1097593).
• CVE-2018-14625: A flaw was found where an attacker may be able to have an uncontrolled read to kernel-memory from within a vm guest. A race condition between connect() and close() function may allow an attacker using the AF_VSOCK protocol to gather a 4 byte information leak or possibly intercept or corrupt AF_VSOCK messages destined to other clients (bnc#1106615).
• CVE-2018-16862: A security flaw was found in a way that the cleancache subsystem clears an inode after the final file truncation (removal). The new file created with the same inode may contain leftover pages from cleancache and the old file data instead of the new one (bnc#1117186).
• CVE-2018-16884: NFS41+ shares mounted in different network namespaces at the same time can make bc_svc_process() use wrong back-channel IDs and cause a use-after-free vulnerability. Thus a malicious container user can cause a host kernel memory corruption and a system panic. Due to the nature of the flaw, privilege escalation cannot be fully ruled out (bnc#1119946).
• CVE-2018-18397: The userfaultfd implementation mishandled access control for certain UFFDIO_ ioctl calls, as demonstrated by allowing local users to write data into holes in a tmpfs file (if the user has read-only access to that file, and that file contains holes), related to fs/userfaultfd.c and mm/userfaultfd.c (bnc#1117656).
• CVE-2018-19407: The vcpu_scan_ioapic function in arch/x86/kvm/x86.c allowed local users to cause a denial of service (NULL pointer dereference and BUG) via crafted system calls that reach a situation where ioapic is uninitialized (bnc#1116841).
• CVE-2018-19854: An issue was discovered in the crypto_report_one() and related functions in crypto/crypto_user.c (the crypto user configuration API) do not fully initialize structures that are copied to userspace, potentially leaking sensitive memory to user programs. NOTE: this is a CVE-2013-2547 regression but with easier exploitability because the attacker did not need a capability (however, the system must have the CONFIG_CRYPTO_USER kconfig option) (bnc#1118428).
• CVE-2018-19985: The function hso_probe read if_num from the USB device (as an u8) and used it without a length check to index an array, resulting in an OOB memory read in hso_probe or hso_get_config_data that could be used by local attackers (bnc#1120743).
• CVE-2018-20169: The USB subsystem mishandled size checks during the reading of an extra descriptor, related to __usb_get_extra_descriptor in drivers/usb/core/usb.c (bnc#1119714).

The following non-security bugs were fixed:

• acpi / CPPC: Check for valid PCC subspace only if PCC is used (bsc#1117115).
• acpi / CPPC: Update all pr_(debug/err) messages to log the susbspace id (bsc#1117115).
• aio: fix spectre gadget in lookup_ioctx (bsc#1120594).
• alsa: cs46xx: Potential NULL dereference in probe (bsc#1051510).
• alsa: emu10k1: Fix potential Spectre v1 vulnerabilities (bsc#1051510).
• alsa: emux: Fix potential Spectre v1 vulnerabilities (bsc#1051510).
• alsa: fireface: fix for state to fetch PCM frames (bsc#1051510).
• alsa: fireface: fix reference to wrong register for clock configuration (bsc#1051510).
• alsa:…

The SUSE Linux Enterprise 12 SP4 kernel for Azure was updated to receive various security and bugfixes.

The following security bugs were fixed:

• CVE-2018-19407: The vcpu_scan_ioapic function in arch/x86/kvm/x86.c allowed local users to cause a denial of service (NULL pointer dereference and BUG) via crafted system calls that reach a situation where ioapic was uninitialized (bnc#1116841).
• CVE-2018-16884: NFS41+ shares mounted in different network namespaces at the same time can make bc_svc_process() use wrong back-channel IDs and cause a use-after-free vulnerability. Thus a malicious container user can cause a host kernel memory corruption and a system panic. Due to the nature of the flaw, privilege escalation cannot be fully ruled out (bnc#1119946).
• CVE-2018-20169: The USB subsystem mishandled size checks during the reading of an extra descriptor, related to __usb_get_extra_descriptor in drivers/usb/core/usb.c (bnc#1119714).
• CVE-2018-9568: In sk_clone_lock of sock.c, there is a possible memory corruption due to type confusion. This could lead to local escalation of privilege with no additional execution privileges needed. User interaction is not needed for exploitation (bnc#1118319).
• CVE-2018-16862: A security flaw was found in the way that the cleancache subsystem clears an inode after the final file truncation (removal). The new file created with the same inode may contain leftover pages from cleancache and the old file data instead of the new one (bnc#1117186).
• CVE-2018-14625: A flaw was found where an attacker may be able to have an uncontrolled read to kernel-memory from within a vm guest. A race condition between connect() and close() function may allow an attacker using the AF_VSOCK protocol to gather a 4 byte information leak or possibly intercept or corrupt AF_VSOCK messages destined to other clients (bnc#1106615).
• CVE-2018-19985: The function hso_probe read if_num from the USB device (as an u8) and used it without a length check to index an array, resulting in an OOB memory read in hso_probe or hso_get_config_data that could be used by local attackers (bnc#1120743).
• CVE-2018-12232: In net/socket.c there is a race condition between fchownat and close in cases where they target the same socket file descriptor, related to the sock_close and sockfs_setattr functions. fchownat did not increment the file descriptor reference count, which allowed close to set the socket to NULL during fchownat's execution, leading to a NULL pointer dereference and system crash (bnc#1097593).
• CVE-2018-18397: The userfaultfd implementation mishandled access control for certain UFFDIO_ ioctl calls, as demonstrated by allowing local users to write data into holes in a tmpfs file (if the user has read-only access to that file, and that file contains holes), related to fs/userfaultfd.c and mm/userfaultfd.c (bnc#1117656).
• CVE-2018-19854: An issue was discovered in the crypto_report_one() and related functions in crypto/crypto_user.c (the crypto user configuration API) do not fully initialize structures that are copied to userspace, potentially leaking sensitive memory to user programs. NOTE: this is a CVE-2013-2547 regression but with easier exploitability because the attacker did not need a capability (however, the system must have the CONFIG_CRYPTO_USER kconfig option) (bnc#1118428).
• CVE-2018-19824: A local user could exploit a use-after-free in the ALSA driver by supplying a malicious USB Sound device (with zero interfaces) that is mishandled in usb_audio_probe in sound/usb/card.c (bnc#1118152).
• CVE-2018-18281: The mremap() syscall performs TLB flushes after dropping pagetable locks. If a syscall such as ftruncate() removes entries from the pagetables of a task that is in the middle of mremap(), a stale TLB entry can remain for a short time that permits access to a physical page after it has been released back to the page allocator and reused. (bnc#1113769).
• CVE-2017-5753: Systems with microprocessors utilizing…

The SUSE Linux Enterprise 15 kernel was updated to receive various security and bugfixes.

This update brings following features:

• Support for Enhanced-IBRS on new Intel CPUs (fate#326564)

The following security bugs were fixed:

• CVE-2018-9568: In sk_clone_lock of sock.c, there is a possible memory corruption due to type confusion. This could lead to local escalation of privilege with no additional execution privileges needed. User interaction is not needed for exploitation. (bnc#1118319).
• CVE-2018-12232: In net/socket.c there is a race condition between fchownat and close in cases where they target the same socket file descriptor, related to the sock_close and sockfs_setattr functions. fchownat did not increment the file descriptor reference count, which allowed close to set the socket to NULL during fchownat's execution, leading to a NULL pointer dereference and system crash (bnc#1097593).
• CVE-2018-14625: A flaw was found where an attacker may be able to have an uncontrolled read to kernel-memory from within a vm guest. A race condition between connect() and close() function may allow an attacker using the AF_VSOCK protocol to gather a 4 byte information leak or possibly intercept or corrupt AF_VSOCK messages destined to other clients (bnc#1106615).
• CVE-2018-16862: A security flaw was found in the way that the cleancache subsystem clears an inode after the final file truncation (removal). The new file created with the same inode may contain leftover pages from cleancache and the old file data instead of the new one (bnc#1117186).
• CVE-2018-16884: NFS41+ shares mounted in different network namespaces at the same time can make bc_svc_process() use wrong back-channel IDs and cause a use-after-free vulnerability. Thus a malicious container user can cause a host kernel memory corruption and a system panic. Due to the nature of the flaw, privilege escalation cannot be fully ruled out (bnc#1119946).
• CVE-2018-18281: The mremap() syscall performs TLB flushes after dropping pagetable locks. If a syscall such as ftruncate() removes entries from the pagetables of a task that is in the middle of mremap(), a stale TLB entry can remain for a short time that permits access to a physical page after it has been released back to the page allocator and reused. (bnc#1113769).
• CVE-2018-18397: The userfaultfd implementation mishandled access control for certain UFFDIO_ ioctl calls, as demonstrated by allowing local users to write data into holes in a tmpfs file (if the user has read-only access to that file, and that file contains holes), related to fs/userfaultfd.c and mm/userfaultfd.c (bnc#1117656).
• CVE-2018-18710: An information leak in cdrom_ioctl_select_disc in drivers/cdrom/cdrom.c could be used by local attackers to read kernel memory because a cast from unsigned long to int interferes with bounds checking. This is similar to CVE-2018-10940 and CVE-2018-16658 (bnc#1113751).
• CVE-2018-19407: The vcpu_scan_ioapic function in arch/x86/kvm/x86.c allowed local users to cause a denial of service (NULL pointer dereference and BUG) via crafted system calls that reach a situation where ioapic is uninitialized (bnc#1116841).
• CVE-2018-19824: A local user could exploit a use-after-free in the ALSA driver by supplying a malicious USB Sound device (with zero interfaces) that is mishandled in usb_audio_probe in sound/usb/card.c (bnc#1118152).
• CVE-2018-19854: An issue was discovered in the crypto_report_one() and related functions in crypto/crypto_user.c (the crypto user configuration API) do not fully initialize structures that are copied to userspace, potentially leaking sensitive memory to user programs. NOTE: this is a CVE-2013-2547 regression but with easier exploitability because the attacker did not need a capability (however, the system must have the CONFIG_CRYPTO_USER kconfig option) (bnc#1118428).
• CVE-2018-19985: The function hso_probe read if_num from the USB device (as an u8) and used it without a length check to…

Jann Horn discovered that the userfaultd implementation in the Linux kernel did not properly restrict access to certain ioctls. A local attacker could use this possibly to modify files. (CVE-2018-18397)

It was discovered that the crypto subsystem of the Linux kernel leaked uninitialized memory to user space in some situations. A local attacker could use this to expose sensitive information (kernel memory). (CVE-2018-19854)

Jann Horn discovered a race condition in the fork() system call in the Linux kernel. A local attacker could use this to gain access to services that cache authorizations. (CVE-2019-6133)

USN-3901-1 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.

Jann Horn discovered that the userfaultd implementation in the Linux kernel did not properly restrict access to certain ioctls. A local attacker could use this possibly to modify files. (CVE-2018-18397)

It was discovered that the crypto subsystem of the Linux kernel leaked uninitialized memory to user space in some situations. A local attacker could use this to expose sensitive information (kernel memory). (CVE-2018-19854)

Jann Horn discovered a race condition in the fork() system call in the Linux kernel. A local attacker could use this to gain access to services that cache authorizations. (CVE-2019-6133)

USN-3903-1 fixed vulnerabilities in the Linux kernel for Ubuntu 18.10. This update provides the corresponding updates for the Linux Hardware Enablement (HWE) kernel from Ubuntu 18.10 for Ubuntu 18.04 LTS.

Jason Wang discovered that the vhost net driver in the Linux kernel contained an out of bounds write vulnerability. An attacker in a guest virtual machine could use this to cause a denial of service (host system crash) or possibly execute arbitrary code in the host kernel. (CVE-2018-16880)

Jann Horn discovered that the userfaultd implementation in the Linux kernel did not properly restrict access to certain ioctls. A local attacker could use this possibly to modify files. (CVE-2018-18397)

Jann Horn discovered a race condition in the fork() system call in the Linux kernel. A local attacker could use this to gain access to services that cache authorizations. (CVE-2019-6133)