1. Release Notes for Unbreakable Enterprise Kernel Release 5 Update 5
  2. Security Fixes for CVEs

2 Security Fixes for CVEs

This chapter lists security vulnerabilities and exposures (CVEs) that are specifically addressed in this release. Note that CVEs are continually handled in patch updates that are made available as errata builds for the current release. For this reason, it is absolutely critical that you keep your system up to date with the latest package updates for this kernel release.

You can keep up to date with the latest CVE information at https://linux.oracle.com/cve.

List of CVEs fixed in this release

The following list describes the CVEs that are fixed in this release. The content provided here is automatically generated and includes the CVE identifier and a summary of the issue. The associated internal Oracle bug identifiers are also included to reference work that was carried out to address each issue.

  • CVE-2018-20669

    An issue where a provided address with access_ok() is not checked was discovered in i915_gem_execbuffer2_ioctl in drivers/gpu/drm/i915/i915_gem_execbuffer.c in the Linux kernel through 4.19.13. A local attacker can craft a malicious IOCTL function call to overwrite arbitrary kernel memory, resulting in a Denial of Service or privilege escalation. A flaw was found in the Linux kernel where a provided address with access_ok() is not checked before accessing userspace data in certain situations. Lack of such checks in i915_gem_execbuffer2_ioctl in drivers/gpu/drm/i915/i915_gem_execbuffer.c may allow a local unprivileged attacker to possible escalate its privileges. (Bug: 31758823 )

    See https://linux.oracle.com/cve/CVE-2018-20669.html for more information.

  • CVE-2019-12380

    **DISPUTED** An issue was discovered in the efi subsystem in the Linux kernel through 5.1.5. phys_efi_set_virtual_address_map in arch/x86/platform/efi/efi.c and efi_call_phys_prolog in arch/x86/platform/efi/efi_64.c mishandle memory allocation failures. NOTE: This id is disputed as not being an issue because “All the code touched by the referenced commit runs only at boot, before any user processes are started. Therefore, there is no possibility for an unprivileged user to control it.”. A flaw was found in the Linux kernel's implementation of UEFI. An attacker who can influence early-boot memory initialization could possibly influence firmware initialization and memory allocations, resulting in a panic of a guest or target system during early boot of that same system. (Bug: 31765890 )

    See https://linux.oracle.com/cve/CVE-2019-12380.html for more information.

  • CVE-2019-16089

    An issue was discovered in the Linux kernel through 5.2.13. nbd_genl_status in drivers/block/nbd.c does not check the nla_nest_start_noflag return value.An improper return check flaw was found in the Linux kernel’s network block device driver functionality when the user call query to check the status of existing network block devices. This flaw allows a local user to crash the system. (Bug: 31351790 )

    See https://linux.oracle.com/cve/CVE-2019-16089.html for more information.

  • CVE-2019-18885

    fs/btrfs/volumes.c in the Linux kernel before 5.1 allows a btrfs_verify_dev_extents NULL pointer dereference via a crafted btrfs image because fs_devices->devices is mishandled within find_device, aka CID-09ba3bc9dd15. (Bug: 31764618 )

    See https://linux.oracle.com/cve/CVE-2019-18885.html for more information.

  • CVE-2019-19377

    In the Linux kernel 5.0.21, mounting a crafted btrfs filesystem image, performing some operations, and unmounting can lead to a use-after-free in btrfs_queue_work in fs/btrfs/async-thread.c. A flaw was found in the Linux kernel's implementation of the BTRFS file system. A local attacker, with the ability to mount a file system, can create a use-after-free memory fault after the file system has been unmounted. This may lead to memory corruption or privilege escalation. (Bug: 31265339 )

    See https://linux.oracle.com/cve/CVE-2019-19377.html for more information.

  • CVE-2019-19448

    In the Linux kernel 5.0.21 and 5.3.11, mounting a crafted btrfs filesystem image, performing some operations, and then making a syncfs system call can lead to a use-after-free in try_merge_free_space in fs/btrfs/free-space-cache.c because the pointer to a left data structure can be the same as the pointer to a right data structure. A flaw was found in the Linux kernel's implementation of BTRFS free space management, where the kernel does not correctly manage the lifetime of internal data structures used. An attacker could use this flaw to corrupt memory or escalate privileges. (Bug: 31351024 )

    See https://linux.oracle.com/cve/CVE-2019-19448.html for more information.

  • CVE-2019-19770

    ** DISPUTED ** In the Linux kernel 4.19.83, there is a use-after-free (read) in the debugfs_remove function in fs/debugfs/inode.c (which is used to remove a file or directory in debugfs that was previously created with a call to another debugfs function such as debugfs_create_file). NOTE: Linux kernel developers dispute this issue as not being an issue with debugfs, instead this is an issue with misuse of debugfs within blktrace.A use-after-free flaw was found in the debugfs_remove function in the Linux kernel. The flaw could allow a local attacker with special user (or root) privilege to crash the system at the time of file or directory removal. This vulnerability can lead to a kernel information leak. The highest threat from this vulnerability is to system availability.

  • CVE-2019-19816

    In the Linux kernel 5.0.21, mounting a crafted btrfs filesystem image and performing some operations can cause slab-out-of-bounds write access in __btrfs_map_block in fs/btrfs/volumes.c, because a value of 1 for the number of data stripes is mishandled. A flaw was found in the implementation of the BTRFS file system code in the Linux kernel. An attacker, who is able to mount a crafted BTRFS filesystem and perform common filesystem operations, can possibly cause an out-of-bounds write to memory. This could lead to memory corruption or privilege escalation. (Bug: 31864725 )

    See https://linux.oracle.com/cve/CVE-2019-19816.html for more information.

  • CVE-2019-3874

    The SCTP socket buffer used by a userspace application is not accounted by the cgroups subsystem. An attacker can use this flaw to cause a denial of service attack. Kernel 3.10.x and 4.18.x branches are believed to be vulnerable.The SCTP socket buffer used by a userspace application is not accounted by the cgroups subsystem. An attacker can use this flaw to cause a denial of service attack. (Bug: 31753070 )

    See https://linux.oracle.com/cve/CVE-2019-3874.html for more information.

  • CVE-2020-10767

    . A flaw was found in the Linux kernel before 5.8-rc1 in the implementation of the Enhanced IBPB (Indirect Branch Prediction Barrier). The IBPB mitigation will be disabled when STIBP is not available or when the Enhanced Indirect Branch Restricted Speculation (IBRS) is available. This flaw allows a local attacker to perform a Spectre V2 style attack when this configuration is active. The highest threat from this vulnerability is to confidentiality. A flaw was found in the Linux kernel’s implementation of the Enhanced IBPB (Indirect Branch Prediction Barrier). The IBPB mitigation will be disabled when STIBP is not available or when the Enhanced Indirect Branch Restricted Speculation (IBRS) is available. This flaw allows a local attacker to perform a Spectre V2 style attack when this configuration is active. The highest threat from this vulnerability is to confidentiality. (Bug: 31711412 )

    See https://linux.oracle.com/cve/CVE-2020-10767.html for more information.

  • CVE-2020-10781

    . A flaw was found in the Linux Kernel before 5.8-rc6 in the ZRAM kernel module, where a user with a local account and the ability to read the /sys/class/zram-control/hot_add file can create ZRAM device nodes in the /dev/ directory. This read allocates kernel memory and is not accounted for a user that triggers the creation of that ZRAM device. With this vulnerability, continually reading the device may consume a large amount of system memory and cause the Out-of-Memory (OOM) killer to activate and terminate random userspace processes, possibly making the system inoperable. A flaw was found in the ZRAM kernel module, where a user with a local account and the ability to read the /sys/class/zram-control/hot_add file can create ZRAM device nodes in the /dev/ directory. This read allocates kernel memory and is not accounted for a user that triggers the creation of that ZRAM device. With this vulnerability, continually reading the device may consume a large amount of system memory and cause the Out-of-Memory (OOM) killer to activate and terminate random userspace processes, possibly making the system inoperable. (Bug: 31726827 )

    See https://linux.oracle.com/cve/CVE-2020-10781.html for more information.

  • CVE-2020-14314

    A memory out-of-bounds read flaw was found in the Linux kernel before 5.9-rc2 with the ext3/ext4 file system, in the way it accesses a directory with broken indexing. This flaw allows a local user to crash the system if the directory exists. The highest threat from this vulnerability is to system availability.A memory out-of-bounds read flaw was found in the Linux kernel's ext3/ext4 file system, in the way it accesses a directory with broken indexing. This flaw allows a local user to crash the system if the directory exists. The highest threat from this vulnerability is to system availability. (Bug: 31895328 )

    See https://linux.oracle.com/cve/CVE-2020-14314.html for more information.

  • CVE-2020-14331

    . A flaw was found in the Linux kernel’s implementation of the invert video code on VGA consoles when a local attacker attempts to resize the console, calling an ioctl VT_RESIZE, which causes an out-of-bounds write to occur. This flaw allows a local user with access to the VGA console to crash the system, potentially escalating their privileges on the system. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability. A flaw was found in the Linux kernel’s implementation of the invert video code on VGA consoles when a local attacker attempts to resize the console, calling an ioctl VT_RESIZE, which causes an out-of-bounds write to occur. This flaw allows a local user with access to the VGA console to crash the system, potentially escalating their privileges on the system. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability. (Bug: 31705118 )

    See https://linux.oracle.com/cve/CVE-2020-14331.html for more information.

  • CVE-2020-14351

    . A flaw was found in the Linux kernel. A use-after-free memory flaw was found in the perf subsystem allowing a local attacker with permission to monitor perf events to corrupt memory and possibly escalate privileges. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability. A flaw was found in the Linux kernel. A use-after-free memory flaw was found in the perf subsystem allowing a local attacker with permission to monitor perf events to corrupt memory and possibly escalate privileges. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability. (Bug: 32233354 )

    See https://linux.oracle.com/cve/CVE-2020-14351.html for more information.

  • CVE-2020-14385

    . A flaw was found in the Linux kernel before 5.9-rc4. A failure of the file system metadata validator in XFS can cause an inode with a valid, user-creatable extended attribute to be flagged as corrupt. This can lead to the filesystem being shutdown, or otherwise rendered inaccessible until it is remounted, leading to a denial of service. The highest threat from this vulnerability is to system availability. A flaw was found in the Linux kernel. A failure of the file system metadata validator in XFS can cause an inode with a valid, user-creatable extended attribute to be flagged as corrupt. This can lead to the filesystem being shutdown, or otherwise rendered inaccessible until it is remounted, leading to a denial of service. The highest threat from this vulnerability is to system availability. (Bug: 31895823 )

    See https://linux.oracle.com/cve/CVE-2020-14385.html for more information.

  • CVE-2020-14386

    . A flaw was found in the Linux kernel before 5.9-rc4. Memory corruption can be exploited to gain root privileges from unprivileged processes. The highest threat from this vulnerability is to data confidentiality and integrity.A flaw was found in the Linux kernel. Memory corruption can be exploited to gain root privileges from unprivileged processes. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability. (Bug: 31866488 )

    See https://linux.oracle.com/cve/CVE-2020-14386.html for more information.

  • CVE-2020-14390

    . A flaw was found in the Linux kernel in versions before 5.9-rc6. When changing screen size, an out-of-bounds memory write can occur leading to memory corruption or a denial of service. Due to the nature of the flaw, privilege escalation cannot be fully ruled out. A flaw was found in the Linux kernel. When changing screen size, an out-of-bounds memory write can occur leading to memory corruption or a denial of service. Due to the nature of the flaw, privilege escalation cannot be fully ruled out. (Bug: 31914674 )

    See https://linux.oracle.com/cve/CVE-2020-14390.html for more information.

  • CVE-2020-16166

    The Linux kernel through 5.7.11 allows remote attackers to make observations that help to obtain sensitive information about the internal state of the network RNG, aka CID-f227e3ec3b5c. This is related to drivers/char/random.c and kernel/time/timer.c. A flaw was found in the Linux kernel. The generation of the device ID from the network RNG internal state is predictable. The highest threat from this vulnerability is to data confidentiality. (Bug: 31698081 )

    See https://linux.oracle.com/cve/CVE-2020-16166.html for more information.

  • CVE-2020-24394

    In the Linux kernel before 5.7.8, fs/nfsd/vfs.c (in the NFS server) can set incorrect permissions on new filesystem objects when the filesystem lacks ACL support, aka CID-22cf8419f131. This occurs because the current umask is not considered.A vulnerability was found in NFSv4.2 in the Linux kernel, where a server fails to correctly apply umask when creating a new object on filesystem without ACL support (for example, ext4 with the "noacl" mount option). This flaw allows a local attacker with a user privilege to cause a kernel information leak problem. (Bug: 31779885 )

    See https://linux.oracle.com/cve/CVE-2020-24394.html for more information.

  • CVE-2020-25211

    In the Linux kernel through 5.8.7, local attackers able to inject conntrack netlink configuration could overflow a local buffer, causing crashes or triggering use of incorrect protocol numbers in ctnetlink_parse_tuple_filter in net/netfilter/nf_conntrack_netlink.c, aka CID-1cc5ef91d2ff.A flaw was found in the Linux kernel. A local attacker, able to inject conntrack netlink configuration, could overflow a local buffer causing crashes or triggering the use of incorrect protocol numbers in ctnetlink_parse_tuple_filter in net/netfilter/nf_conntrack_netlink.c. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability. (Bug: 31872860 )

    See https://linux.oracle.com/cve/CVE-2020-25211.html for more information.

  • CVE-2020-25212

    A TOCTOU mismatch in the NFS client code in the Linux kernel before 5.8.3 could be used by local attackers to corrupt memory or possibly have unspecified other impact because a size check is in fs/nfs/nfs4proc.c instead of fs/nfs/nfs4xdr.c, aka CID-b4487b935452. A flaw was found in the NFSv4 implementation where when mounting a remote attacker controlled server it could return specially crafted response allow for local memory corruption and possibly privilege escalation. (Bug: 31872898 )

    See https://linux.oracle.com/cve/CVE-2020-25212.html for more information.

  • CVE-2020-25284

    The rbd block device driver in drivers/block/rbd.c in the Linux kernel through 5.8.9 used incomplete permission checking for access to rbd devices, which could be leveraged by local attackers to map or unmap rbd block devices, aka CID-f44d04e696fe. A flaw was found in the capabilities check of the rados block device functionality in the Linux kernel. Incorrect capability checks could alllow a local user with root priviledges (but no capabilities) to add or remove Rados Block Devices from the system. (Bug: 31884161 )

    See https://linux.oracle.com/cve/CVE-2020-25284.html for more information.

  • CVE-2020-25285

    A race condition between hugetlb sysctl handlers in mm/hugetlb.c in the Linux kernel before 5.8.8 could be used by local attackers to corrupt memory, cause a NULL pointer dereference, or possibly have unspecified other impact, aka CID-17743798d812. A flaw was found in the Linux kernels sysctl handling code for hugepages management. When multiple root level processes would write to modify the /proc/sys/vm/nr_hugepages file it could create a race on internal variables leading to a system crash or memory corruption. (Bug: 31884237 )

    See https://linux.oracle.com/cve/CVE-2020-25285.html for more information.

  • CVE-2020-25641

    . A flaw was found in the Linux kernel's implementation of biovecs in versions before 5.9-rc7. A zero-length biovec request issued by the block subsystem could cause the kernel to enter an infinite loop, causing a denial of service. This flaw allows a local attacker with basic privileges to issue requests to a block device, resulting in a denial of service. The highest threat from this vulnerability is to system availability. A flaw was found in the Linux kernel’s implementation of biovecs. A zero-length biovec request issued by the block subsystem could cause the kernel to enter an infinite loop, causing a denial of service. This flaw allows a local attacker with basic privileges to issue requests to a block device, resulting in a denial of service. The highest threat from this vulnerability is to system availability. (Bug: 31955140 )

    See https://linux.oracle.com/cve/CVE-2020-25641.html for more information.

  • CVE-2020-25643

    . A flaw was found in the HDLC_PPP module of the Linux kernel in versions before 5.9-rc7. Memory corruption and a read overflow is caused by improper input validation in the ppp_cp_parse_cr function which can cause the system to crash or cause a denial of service. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability. A flaw was found in the HDLC_PPP module of the Linux kernel. Memory corruption and a read overflow is caused by improper input validation in the ppp_cp_parse_cr function which can cause the system to crash or cause a denial of service. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability. (Bug: 31989188 )

    See https://linux.oracle.com/cve/CVE-2020-25643.html for more information.

  • CVE-2020-25645

    . A flaw was found in the Linux kernel in versions before 5.9-rc7. Traffic between two Geneve endpoints may be unencrypted when IPsec is configured to encrypt traffic for the specific UDP port used by the GENEVE tunnel allowing anyone between the two endpoints to read the traffic unencrypted. The main threat from this vulnerability is to data confidentiality. A flaw was found in the Linux kernel. Traffic between two Geneve endpoints may be unencrypted when IPsec is configured to encrypt traffic for the specific UDP port used by the GENEVE tunnel allowing anyone in between the two endpoints to read the traffic unencrypted. The main threat from this vulnerability is to data confidentiality. (Bug: 32014098 )

    See https://linux.oracle.com/cve/CVE-2020-25645.html for more information.

  • CVE-2020-25656

    . A flaw was found in the Linux kernel. A use-after-free was found in the way the console subsystem was using ioctls KDGKBSENT and KDSKBSENT. A local user could use this flaw to get read memory access out of bounds. The highest threat from this vulnerability is to data confidentiality. A flaw was found in the Linux kernel. A use-after-free was found in the way the console subsystem was using ioctls KDGKBSENT and KDSKBSENT. A local user could use this flaw to get read memory access out of bounds. The highest threat from this vulnerability is to data confidentiality.

    See https://linux.oracle.com/cve/CVE-2020-25656.html for more information.

  • CVE-2020-25704

    . A flaw memory leak in the Linux kernel performance monitoring subsystem was found in the way if using PERF_EVENT_IOC_SET_FILTER. A local user could use this flaw to starve the resources causing denial of service.A memory leak flaw was found in the Linux kernel’s performance monitoring subsystem when using PERF_EVENT_IOC_SET_FILTER. This flaw allows a local user to starve the resources, causing a denial of service. The highest threat from this vulnerability is to system availability. (Bug: 32131174 )

    See https://linux.oracle.com/cve/CVE-2020-25704.html for more information.

  • CVE-2020-26541

    The Linux kernel through 5.8.13 does not properly enforce the Secure Boot Forbidden Signature Database (aka dbx) protection mechanism. This affects certs/blacklist.c and certs/system_keyring.c. A flaw was found in the Linux kernel in certs/blacklist.c, When signature entries for EFI_CERT_X509_GUID are contained in the Secure Boot Forbidden Signature Database, the entries are skipped. This can cause a security threat and breach system integrity, confidentiality and even lead to a denial of service problem. (Bug: 31961117 )

    See https://linux.oracle.com/cve/CVE-2020-26541.html for more information.

  • CVE-2020-27673

    An issue was discovered in the Linux kernel through 5.9.1, as used with Xen through 4.14.x. Guest OS users can cause a denial of service (host OS hang) via a high rate of events to dom0, aka CID-e99502f76271. (Bug: 32177537 )

    See https://linux.oracle.com/cve/CVE-2020-27673.html for more information.

  • CVE-2020-28374

    In drivers/target/target_core_xcopy.c in the Linux kernel before 5.10.7, insufficient identifier checking in the LIO SCSI target code can be used by remote attackers to read or write files via directory traversal in an XCOPY request, aka CID-2896c93811e3. For example, an attack can occur over a network if the attacker has access to one iSCSI LUN. The attacker gains control over file access because I/O operations are proxied via an attacker-selected backstore.A flaw was found in the Linux kernel’s implementation of the Linux SCSI target host, where an authenticated attacker could write to any block on the exported SCSI device backing store. This flaw allows an authenticated attacker to send LIO block requests to the Linux system to overwrite data on the backing store. The highest threat from this vulnerability is to integrity. In addition, this flaw affects the tcmu-runner package, where the affected SCSI command is called. (Bug: 32248037 )

    See https://linux.oracle.com/cve/CVE-2020-28374.html for more information.

  • CVE-2020-29568

    (Bug: 32253411 )

    See https://linux.oracle.com/cve/CVE-2020-29568.html for more information.

  • CVE-2020-29569

    (Bug: 32260255 )

    See https://linux.oracle.com/cve/CVE-2020-29569.html for more information.

  • CVE-2020-29660

    A locking inconsistency issue was discovered in the tty subsystem of the Linux kernel through 5.9.13. drivers/tty/tty_io.c and drivers/tty/tty_jobctrl.c may allow a read-after-free attack against TIOCGSID, aka CID-c8bcd9c5be24. (Bug: 32266679 )

    See https://linux.oracle.com/cve/CVE-2020-29660.html for more information.

  • CVE-2020-36158

    mwifiex_cmd_802_11_ad_hoc_start in drivers/net/wireless/marvell/mwifiex/join.c in the Linux kernel through 5.10.4 might allow remote attackers to execute arbitrary code via a long SSID value, aka CID-5c455c5ab332. A flaw was found in the Linux kernel. The marvell wifi driver could allow a local attacker to execute arbitrary code via a long SSID value in mwifiex_cmd_802_11_ad_hoc_start function. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.

    See https://linux.oracle.com/cve/CVE-2020-36158.html for more information.