-------------------------------------------------------------------------Debian LTS Advisory DLA-2420-2                debian-lts@lists.debian.org
https://www.debian.org/lts/security/                        Ben Hutchings
October 31, 2020                              https://wiki.debian.org/LTS
-------------------------------------------------------------------------Package        : linux
Version        : 4.9.240-2
CVE ID         : CVE-2019-9445 CVE-2019-19073 CVE-2019-19074 CVE-2019-19448
                 CVE-2020-12351 CVE-2020-12352 CVE-2020-12655 CVE-2020-12771
                 CVE-2020-12888 CVE-2020-14305 CVE-2020-14314 CVE-2020-14331
                 CVE-2020-14356 CVE-2020-14386 CVE-2020-14390 CVE-2020-15393
                 CVE-2020-16166 CVE-2020-24490 CVE-2020-25211 CVE-2020-25212
                 CVE-2020-25220 CVE-2020-25284 CVE-2020-25285 CVE-2020-25641
                 CVE-2020-25643 CVE-2020-26088

This update corrects a regression in some Xen virtual machine
environments.  For reference the original advisory text follows.

Several vulnerabilities have been discovered in the Linux kernel that
may lead to the execution of arbitrary code, privilege escalation,
denial of service or information leaks.

CVE-2019-9445

    A potential out-of-bounds read was discovered in the F2FS
    implementation.  A user permitted to mount and access arbitrary
    filesystems could potentially use this to cause a denial of
    service (crash) or to read sensitive information.

CVE-2019-19073, CVE-2019-19074

    Navid Emamdoost discovered potential memory leaks in the ath9k and
    ath9k_htc drivers.  The security impact of these is unclear.

CVE-2019-19448

    "Team bobfuzzer" reported a bug in Btrfs that could lead to a
    use-after-free, and could be triggered by crafted filesystem
    images.  A user permitted to mount and access arbitrary
    filesystems could use this to cause a denial of service (crash or
    memory corruption) or possibly for privilege escalation.

CVE-2020-12351

    Andy Nguyen discovered a flaw in the Bluetooth implementation in
    the way L2CAP packets with A2MP CID are handled.  A remote attacker
    within a short distance, knowing the victim's Bluetooth device
    address, can send a malicious l2cap packet and cause a denial of
    service or possibly arbitrary code execution with kernel
    privileges.

CVE-2020-12352

    Andy Nguyen discovered a flaw in the Bluetooth implementation.
    Stack memory is not properly initialised when handling certain AMP
    packets.  A remote attacker within a short distance, knowing the
    victim's Bluetooth device address address, can retrieve kernel
    stack information.

CVE-2020-12655

    Zheng Bin reported that crafted XFS volumes could trigger a system
    hang.  An attacker able to mount such a volume could use this to
    cause a denial of service.

CVE-2020-12771

    Zhiqiang Liu reported a bug in the bcache block driver that could
    lead to a system hang.  The security impact of this is unclear.

CVE-2020-12888

    It was discovered that the PCIe Virtual Function I/O (vfio-pci)
    driver allowed users to disable a device's memory space while it
    was still mapped into a process.  On some hardware platforms,
    local users or guest virtual machines permitted to access PCIe
    Virtual Functions could use this to cause a denial of service
    (hardware error and crash).

CVE-2020-14305

    Vasily Averin of Virtuozzo discovered a potential heap buffer
    overflow in the netfilter nf_contrack_h323 module.  When this
    module is used to perform connection tracking for TCP/IPv6, a
    remote attacker could use this to cause a denial of service (crash
    or memory corruption) or possibly for remote code execution with
    kernel privilege.

CVE-2020-14314

    A bug was discovered in the ext4 filesystem that could lead to an
    out-of-bound read.  A local user permitted to mount and access
    arbitrary filesystem images could use this to cause a denial of
    service (crash).

CVE-2020-14331

    A bug was discovered in the VGA console driver's soft-scrollback
    feature that could lead to a heap buffer overflow.  On a system
    with a custom kernel that has CONFIG_VGACON_SOFT_SCROLLBACK
    enabled, a local user with access to a console could use this to
    cause a denial of service (crash or memory corruption) or possibly
    for privilege escalation.

CVE-2020-14356, CVE-2020-25220

    A bug was discovered in the cgroup subsystem's handling of socket
    references to cgroups.  In some cgroup configurations, this could
    lead to a use-after-free.  A local user might be able to use this
    to cause a denial of service (crash or memory corruption) or
    possibly for privilege escalation.

    The original fix for this bug introudced a new security issue,
    which is also addressed in this update.

CVE-2020-14386

    Or Cohen discovered a bug in the packet socket (AF_PACKET)
    implementation which could lead to a heap buffer overflow.  A
    local user with the CAP_NET_RAW capability (in any user namespace)
    could use this to cause a denial of service (crash or memory
    corruption) or possibly for privilege escalation.

CVE-2020-14390

    Minh Yuan discovered a bug in the framebuffer console driver's
    scrollback feature that could lead to a heap buffer overflow.  On
    a system using framebuffer consoles, a local user with access to a
    console could use this to cause a denial of service (crash or
    memory corruption) or possibly for privilege escalation.

    The scrollback feature has been disabled for now, as no other fix
    was available for this issue.

CVE-2020-15393

    Kyungtae Kim reported a memory leak in the usbtest driver.  The
    security impact of this is unclear.

CVE-2020-16166

    Amit Klein reported that the random number generator used by the
    network stack might not be re-seeded for long periods of time,
    making e.g. client port number allocations more predictable.  This
    made it easier for remote attackers to carry out some network-    based attacks such as DNS cache poisoning or device tracking.

CVE-2020-24490

    Andy Nguyen discovered a flaw in the Bluetooth implementation that
    can lead to a heap buffer overflow.  On systems with a Bluetooth 5
    hardware interface, a remote attacker within a short distance can
    use this to cause a denial of service (crash or memory corruption)
    or possibly for remote code execution with kernel privilege.

CVE-2020-25211

    A flaw was discovered in netfilter subsystem.  A local attacker
    able to inject conntrack Netlink configuration can cause a denial
    of service.

CVE-2020-25212

    A bug was discovered in the NFSv4 client implementation that could
    lead to a heap buffer overflow.  A malicious NFS server could use
    this to cause a denial of service (crash or memory corruption) or
    possibly to execute arbitrary code on the client.

CVE-2020-25284

    It was discovered that the Rados block device (rbd) driver allowed
    tasks running as uid 0 to add and remove rbd devices, even if they
    dropped capabilities.  On a system with the rbd driver loaded,
    this might allow privilege escalation from a container with a task
    running as root.

CVE-2020-25285

    A race condition was discovered in the hugetlb filesystem's sysctl
    handlers, that could lead to stack corruption.  A local user
    permitted to write to hugepages sysctls could use this to cause a
    denial of service (crash or memory corruption) or possibly for
    privilege escalation.  By default only the root user can do this.

CVE-2020-25641

    The syzbot tool found a bug in the block layer that could lead to
    an infinite loop.  A local user with access to a raw block device
    could use this to cause a denial of service (unbounded CPU use and
    possible system hang).

CVE-2020-25643

    ChenNan Of Chaitin Security Research Lab discovered a flaw in the
    hdlc_ppp module.  Improper input validation in the ppp_cp_parse_cr()
    function may lead to memory corruption and information disclosure.

CVE-2020-26088

    It was discovered that the NFC (Near Field Communication) socket
    implementation allowed any user to create raw sockets.  On a
    system with an NFC interface, this allowed local users to evade
    local network security policy.

For Debian 9 stretch, these problems have been fixed in version
4.9.240-1.  This update additionally includes many more bug fixes from
stable updates 4.9.229-4.9.240 inclusive.

We recommend that you upgrade your linux packages.

For the detailed security status of linux please refer to
its security tracker page at:
https://security-tracker.debian.org/tracker/source-package/linux

Further information about Debian LTS security advisories, how to apply
these updates to your system and frequently asked questions can be
found at: https://wiki.debian.org/LTS

-- 
Ben Hutchings - Debian developer, member of kernel, installer and LTS teams