CVE-2018-15471

An issue was discovered in xenvif_set_hash_mapping in drivers/net/xen-netback/hash.c in the Linux kernel through 4.18.1, as used in Xen through 4.11.x and other products. The Linux netback driver allows frontends to control mapping of requests to request queues. When processing a request to set or change this mapping, some input validation (e.g., for an integer overflow) was missing or flawed, leading to OOB access in hash handling. A malicious or buggy frontend may cause the (usually privileged) backend to make out of bounds memory accesses, potentially resulting in one or more of privilege escalation, Denial of Service (DoS), or information leaks.

An issue was discovered in xenvif_set_hash_mapping in drivers/net/xen-netback/hash.c in the Linux kernel through 4.18.1, as used in Xen through 4.11.x and other products. The Linux netback driver allows frontends to control mapping of requests to request queues. When processing a request to set or change this mapping, some input validation (e.g., for an integer overflow) was missing or flawed, leading to OOB access in hash handling. A malicious or buggy frontend may cause the (usually privileged) backend to make out of bounds memory accesses, potentially resulting in one or more of privilege escalation, Denial of Service (DoS), or information leaks.

This kernel update is based on the upstream 4.14.78 and fixes at least the following security issues:

An issue was discovered in the fd_locked_ioctl function in drivers/block/floppy.c in the Linux kernel through 4.15.7. The floppy driver will copy a kernel pointer to user memory in response to the FDGETPRM ioctl. An attacker can send the FDGETPRM ioctl and use the obtained kernel pointer to discover the location of kernel code and data and bypass kernel security protections such as KASLR (CVE-2018-7755).

A security flaw was found in the chap_server_compute_md5() function in the ISCSI target code in the Linux kernel in a way an authentication request from an ISCSI initiator is processed. An unauthenticated remote attacker can cause a stack buffer overflow and smash up to 17 bytes of the stack. The attack requires the iSCSI target to be enabled on the victim host. Depending on how the target's code was built (i.e. depending on a compiler, compile flags and hardware architecture) an attack may lead to a system crash and thus to a denial-of-service or possibly to a non-authorized access to data exported by an iSCSI target. Due to the nature of the flaw, privilege escalation cannot be fully ruled out, although we believe it is highly unlikely (CVE-2018-14633).

An issue was discovered in xenvif_set_hash_mapping in drivers/net/xen-netback/hash.c in the Linux kernel through 4.18.1, as used in Xen through 4.11.x and other products. The Linux netback driver allows frontends to control mapping of requests to request queues. When processing a request to set or change this mapping, some input validation (e.g., for an integer overflow) was missing or flawed, leading to OOB access in hash handling. A malicious or buggy frontend may cause the (usually privileged) backend to make out of bounds memory accesses, potentially resulting in one or more of privilege escalation, Denial of Service (DoS), or information leaks (CVE-2018-15471).

Since Linux kernel version 3.2, 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 (CVE-2018-18281).

In the Linux kernel 4.14.x, 4.15.x, 4.16.x, 4.17.x, and 4.18.x before 4.18.13, faulty computation of numeric bounds in the BPF verifier permits out-of-bounds memory accesses because adjust_scalar_min_max_vals in kernel/bpf/verifier.c mishandles 32-bit right shifts (CVE-2018-18445).

Other fixes in this update:

• WireGuard has been updated 0.0.20181018

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

This kernel-tmb update is based on the upstream 4.14.78 and adds additional fixes for the L1TF security issues. It also fixes at least the following security issues:

Linux kernel from versions 3.9 and up, is vulnerable to a denial of service attack with low rates of specially modified packets targeting IP fragment re-assembly. An attacker may cause a denial of service condition by sending specially crafted IP fragments (CVE-2018-5391, FragmentSmack).

An issue was discovered in the fd_locked_ioctl function in drivers/block/floppy.c in the Linux kernel through 4.15.7. The floppy driver will copy a kernel pointer to user memory in response to the FDGETPRM ioctl. An attacker can send the FDGETPRM ioctl and use the obtained kernel pointer to discover the location of kernel code and data and bypass kernel security protections such as KASLR (CVE-2018-7755).

A security flaw was found in the chap_server_compute_md5() function in the ISCSI target code in the Linux kernel in a way an authentication request from an ISCSI initiator is processed. An unauthenticated remote attacker can cause a stack buffer overflow and smash up to 17 bytes of the stack. The attack requires the iSCSI target to be enabled on the victim host. Depending on how the target's code was built (i.e. depending on a compiler, compile flags and hardware architecture) an attack may lead to a system crash and thus to a denial-of-service or possibly to a non-authorized access to data exported by an iSCSI target. Due to the nature of the flaw, privilege escalation cannot be fully ruled out, although we believe it is highly unlikely (CVE-2018-14633).

A security flaw was found in the ip_frag_reasm() function in net/ipv4/ip_fragment.c in the Linux kernel caused by fixes for CVE-2018-5391, which can cause a later system crash in ip_do_fragment(). With certain non-default, but non-rare, configuration of a victim host, an attacker can trigger this crash remotely, thus leading to a remote denial-of-service (CVE-2018-14641).

An issue was discovered in xenvif_set_hash_mapping in drivers/net/xen-netback/hash.c in the Linux kernel through 4.18.1, as used in Xen through 4.11.x and other products. The Linux netback driver allows frontends to control mapping of requests to request queues. When processing a request to set or change this mapping, some input validation (e.g., for an integer overflow) was missing or flawed, leading to OOB access in hash handling. A malicious or buggy frontend may cause the (usually privileged) backend to make out of bounds memory accesses, potentially resulting in one or more of privilege escalation, Denial of Service (DoS), or information leaks (CVE-2018-15471).

An issue was discovered in the Linux kernel through 4.18.8. The vmacache_flush_all function in mm/vmacache.c mishandles sequence number overflows. An attacker can trigger a use-after-free (and possibly gain privileges) via certain thread creation, map, unmap, invalidation, and dereference operations (CVE-2018-17182).

Since Linux kernel version 3.2, 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 (CVE-2018-18281).

In the Linux kernel 4.14.x, 4.15.x, 4.16.x, 4.17.x, and 4.18.x before 4.18.13, faulty computation of numeric bounds in the BPF verifier permits out-of-bounds memory accesses because adjust_scalar_min_max_vals in kernel/bpf/verifier.c mishandles 32-bit right shifts (CVE-2018-18445).

Other fixes in this update:

• WireGuard has been updated 0.0.20181018

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

This kernel-linus update is based on the upstream 4.14.78 and adds additional fixes for the L1TF security issues. It also fixes at least the following security issues:

Linux kernel from versions 3.9 and up, is vulnerable to a denial of service attack with low rates of specially modified packets targeting IP fragment re-assembly. An attacker may cause a denial of service condition by sending specially crafted IP fragments (CVE-2018-5391, FragmentSmack).

Memory leak in the irda_bind function in net/irda/af_irda.c and later in drivers/staging/irda/net/af_irda.c in the Linux kernel before 4.17 allows local users to cause a denial of service (memory consumption) by repeatedly binding an AF_IRDA socket (CVE-2018-6554).

The irda_setsockopt function in net/irda/af_irda.c and later in drivers/staging/irda/net/af_irda.c in the Linux kernel before 4.17 allows local users to cause a denial of service (ias_object use-after-free and system crash) or possibly have unspecified other impact via an AF_IRDA socket (CVE-2018-6555).

An issue was discovered in the fd_locked_ioctl function in drivers/block/floppy.c in the Linux kernel through 4.15.7. The floppy driver will copy a kernel pointer to user memory in response to the FDGETPRM ioctl. An attacker can send the FDGETPRM ioctl and use the obtained kernel pointer to discover the location of kernel code and data and bypass kernel security protections such as KASLR (CVE-2018-7755).

A security flaw was found in the chap_server_compute_md5() function in the ISCSI target code in the Linux kernel in a way an authentication request from an ISCSI initiator is processed. An unauthenticated remote attacker can cause a stack buffer overflow and smash up to 17 bytes of the stack. The attack requires the iSCSI target to be enabled on the victim host. Depending on how the target's code was built (i.e. depending on a compiler, compile flags and hardware architecture) an attack may lead to a system crash and thus to a denial-of-service or possibly to a non-authorized access to data exported by an iSCSI target. Due to the nature of the flaw, privilege escalation cannot be fully ruled out, although we believe it is highly unlikely (CVE-2018-14633).

A security flaw was found in the ip_frag_reasm() function in net/ipv4/ip_fragment.c in the Linux kernel caused by fixes for CVE-2018-5391, which can cause a later system crash in ip_do_fragment(). With certain non-default, but non-rare, configuration of a victim host, an attacker can trigger this crash remotely, thus leading to a remote denial-of-service (CVE-2018-14641).

An issue was discovered in xenvif_set_hash_mapping in drivers/net/xen-netback/hash.c in the Linux kernel through 4.18.1, as used in Xen through 4.11.x and other products. The Linux netback driver allows frontends to control mapping of requests to request queues. When processing a request to set or change this mapping, some input validation (e.g., for an integer overflow) was missing or flawed, leading to OOB access in hash handling. A malicious or buggy frontend may cause the (usually privileged) backend to make out of bounds memory accesses, potentially resulting in one or more of privilege escalation, Denial of Service (DoS), or information leaks (CVE-2018-15471).

An issue was discovered in the Linux kernel through 4.18.8. The vmacache_flush_all function in mm/vmacache.c mishandles sequence number overflows. An attacker can trigger a use-after-free (and possibly gain privileges) via certain thread creation, map, unmap, invalidation, and dereference operations (CVE-2018-17182).

Since Linux kernel version 3.2, 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 (CVE-2018-18281).

In the Linux kernel 4.14.x,…

This update for the Linux Kernel 4.12.14-23 fixes one issue.

The following security issue was fixed:

• CVE-2018-15471: An issue was discovered in xenvif_set_hash_mapping in drivers/net/xen-netback/hash.c. The Linux netback driver allowed frontends to control mapping of requests to request queues. When processing a request to set or change this mapping, some input validation (e.g., for an integer overflow) was missing or flawed, leading to OOB access in hash handling. A malicious or buggy frontend may cause the (usually privileged) backend to make out of bounds memory accesses, potentially resulting in one or more of privilege escalation, Denial of Service (DoS), or information leaks (bsc#1105026).

This update for the Linux Kernel 4.12.14-25_6 fixes several issues.

The following security issues were fixed:

• CVE-2018-15471: An issue was discovered in xenvif_set_hash_mapping in drivers/net/xen-netback/hash.c. The Linux netback driver allowed frontends to control mapping of requests to request queues. When processing a request to set or change this mapping, some input validation (e.g., for an integer overflow) was missing or flawed, leading to OOB access in hash handling. A malicious or buggy frontend may cause the (usually privileged) backend to make out of bounds memory accesses, potentially resulting in one or more of privilege escalation, Denial of Service (DoS), or information leaks (bsc#1105026).
• CVE-2018-10853: A KVM guest userspace to guest kernel write was fixed, which could be used by guest users to crash the guest kernel (bsc#1097108).

This update for the Linux Kernel 4.12.14-25_11 fixes several issues.

The following security issues were fixed:

• CVE-2018-15471: An issue was discovered in xenvif_set_hash_mapping in drivers/net/xen-netback/hash.c. The Linux netback driver allowed frontends to control mapping of requests to request queues. When processing a request to set or change this mapping, some input validation (e.g., for an integer overflow) was missing or flawed, leading to OOB access in hash handling. A malicious or buggy frontend may cause the (usually privileged) backend to make out of bounds memory accesses, potentially resulting in one or more of privilege escalation, Denial of Service (DoS), or information leaks (bsc#1105026).
• CVE-2018-10853: A KVM guest userspace to guest kernel write was fixed, which could be used by guest users to crash the guest kernel (bsc#1097108).

This update for the Linux Kernel 4.12.14-25_13 fixes several issues.

The following security issues were fixed:

• CVE-2018-10938: It was found that a crafted network packet sent remotely by an attacker may force the kernel to enter an infinite loop in the cipso_v4_optptr() function in net/ipv4/cipso_ipv4.c leading to a denial-of-service. A certain non-default configuration of LSM (Linux Security Module) and NetLabel should be set up on a system an attacker could leverage this flaw (bsc#1106191).
• CVE-2018-15471: It was found that the netback driver allowed frontends to control mapping of requests to request queues. When processing a request to set or change this mapping, some input validation (e.g., for an integer overflow) was missing or flawed, leading to OOB access in hash handling. A malicious or buggy frontend may caused the (usually privileged) backend to make out of bounds memory accesses, potentially resulting in one or more of privilege escalation, Denial of Service (DoS), or information leaks (bsc#1105026).
• CVE-2018-10853: It was found that the KVM hypervisor emulated instructions did not check current privilege(CPL) level while emulating unprivileged instructions. An unprivileged guest user/process could use this flaw to potentially escalate privileges inside guest (bsc#1097108).

Felix Wilhelm discovered that the Xen netback driver in the Linux kernel did not properly perform input validation in some situations. An attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2018-15471)

It was discovered that the generic SCSI driver in the Linux kernel did not properly enforce permissions on kernel memory access. A local attacker could use this to expose sensitive information or possibly elevate privileges. (CVE-2017-13168)

It was discovered that an integer overflow existed in the CD-ROM driver of the Linux kernel. A local attacker could use this to expose sensitive information (kernel memory). (CVE-2018-16658)

It was discovered that an integer overflow existed in the HID Bluetooth implementation in the Linux kernel that could lead to a buffer overwrite. An attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2018-9363)

USN-3820-1 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.

Felix Wilhelm discovered that the Xen netback driver in the Linux kernel did not properly perform input validation in some situations. An attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2018-15471)

It was discovered that the generic SCSI driver in the Linux kernel did not properly enforce permissions on kernel memory access. A local attacker could use this to expose sensitive information or possibly elevate privileges. (CVE-2017-13168)

It was discovered that an integer overflow existed in the CD-ROM driver of the Linux kernel. A local attacker could use this to expose sensitive information (kernel memory). (CVE-2018-16658)

It was discovered that an integer overflow existed in the HID Bluetooth implementation in the Linux kernel that could lead to a buffer overwrite. An attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2018-9363)

Felix Wilhelm discovered that the Xen netback driver in the Linux kernel did not properly perform input validation in some situations. An attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2018-15471)

It was discovered that the generic SCSI driver in the Linux kernel did not properly enforce permissions on kernel memory access. A local attacker could use this to expose sensitive information or possibly elevate privileges. (CVE-2017-13168)

It was discovered that an integer overflow existed in the CD-ROM driver of the Linux kernel. A local attacker could use this to expose sensitive information (kernel memory). (CVE-2018-16658)

It was discovered that an integer overflow existed in the HID Bluetooth implementation in the Linux kernel that could lead to a buffer overwrite. An attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2018-9363)