7.2 - DSA-4188

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

CVE-2017-5715

Multiple researchers have discovered a vulnerability in various processors supporting speculative execution, enabling an attacker controlling an unprivileged process to read memory from arbitrary addresses, including from the kernel and all other processes running on the system.

This specific attack has been named Spectre variant 2 (branch target injection) and is mitigated for the x86 architecture (amd64 and i386) by using the "retpoline" compiler feature which allows indirect branches to be isolated from speculative execution.

CVE-2017-5753

Multiple researchers have discovered a vulnerability in various processors supporting speculative execution, enabling an attacker controlling an unprivileged process to read memory from arbitrary addresses, including from the kernel and all other processes running on the system.

This specific attack has been named Spectre variant 1 (bounds-check bypass) and is mitigated by identifying vulnerable code sections (array bounds checking followed by array access) and replacing the array access with the speculation-safe array_index_nospec() function.

More use sites will be added over time.

CVE-2017-17975

Tuba Yavuz reported a use-after-free flaw in the USBTV007 audio-video grabber driver. A local user could use this for denial of service by triggering failure of audio registration.

CVE-2017-18193

Yunlei He reported that the f2fs implementation does not properly handle extent trees, allowing a local user to cause a denial of service via an application with multiple threads.

CVE-2017-18216

Alex Chen reported that the OCFS2 filesystem failed to hold a necessary lock during nodemanager sysfs file operations, potentially leading to a null pointer dereference. A local user could use this for denial of service.

CVE-2017-18218

Jun He reported a user-after-free flaw in the Hisilicon HNS ethernet driver. A local user could use this for denial of service.

CVE-2017-18222

It was reported that the Hisilicon Network Subsystem (HNS) driver implementation does not properly handle ethtool private flags. A local user could use this for denial of service or possibly have other impact.

CVE-2017-18224

Alex Chen reported that the OCFS2 filesystem omits the use of a semaphore and consequently has a race condition for access to the extent tree during read operations in DIRECT mode. A local user could use this for denial of service.

CVE-2017-18241

Yunlei He reported that the f2fs implementation does not properly initialise its state if the "noflush_merge" mount option is used. A local user with access to a filesystem mounted with this option could use this to cause a denial of service.

CVE-2017-18257

It was reported that the f2fs implementation is prone to an infinite loop caused by an integer overflow in the __get_data_block() function. A local user can use this for denial of service via crafted use of the open and fallocate system calls with an FS_IOC_FIEMAP ioctl.

CVE-2018-1065

The syzkaller tool found a NULL pointer dereference flaw in the netfilter subsystem when handling certain malformed iptables rulesets. A local user with the CAP_NET_RAW or CAP_NET_ADMIN capability (in any user namespace) could use this to cause a denial of service. Debian disables unprivileged user namespaces by default.

CVE-2018-1066

Dan Aloni reported to Red Hat that the CIFS client implementation would dereference a null pointer if the server sent an invalid response during NTLMSSP setup negotiation. This could be used by a malicious server for denial of service.

CVE-2018-1068

The syzkaller tool found that the 32-bit compatibility layer of ebtables did not sufficiently validate offset values. On a 64-bit kernel, a local user with the CAP_NET_ADMIN capability (in any user namespace) could use this to overwrite kernel memory, possibly leading to privilege escalation. Debian disables unprivileged user namespaces by default.

CVE-2018-1092

Wen Xu reported that a crafted ext4 filesystem image would trigger a null dereference when mounted. A local user able to mount arbitrary filesystems could use this for denial of service.

CVE-2018-1093

Wen Xu reported that a crafted ext4 filesystem image could trigger an out-of-bounds read in the ext4_valid_block_bitmap() function. A local user able to mount arbitrary filesystems could use this for denial of service.

CVE-2018-1108

Jann Horn reported that crng_ready() does not properly handle the crng_init variable states and the RNG could be treated as cryptographically safe too early after system boot.

CVE-2018-5803

Alexey Kodanev reported that the SCTP protocol did not range-check the length of chunks to be created. A local or remote user could use this to cause a denial of service.

CVE-2018-7480

Hou Tao discovered a double-free flaw in the blkcg_init_queue() function in block/blk-cgroup.c. A local user could use this to cause a denial of service or have other impact.

CVE-2018-7566

Fan LongFei reported a race condition in the ALSA (sound) sequencer core, between write and ioctl operations. This could lead to an out-of-bounds access or use-after-free. A local user with access to a sequencer device could use this for denial of service or possibly for privilege escalation.

CVE-2018-7740

Nic Losby reported that the hugetlbfs filesystem's mmap operation did not properly range-check the file offset. A local user with access to files on a hugetlbfs filesystem could use this to cause a denial of service.

CVE-2018-7757

Jason Yan reported a memory leak in the SAS (Serial-Attached SCSI) subsystem. A local user on a system with SAS devices could use this to cause a denial of service.

CVE-2018-7995

Seunghun Han reported a race condition in the x86 MCE (Machine Check Exception) driver. This is unlikely to have any security impact.

CVE-2018-8087

A memory leak flaw was found in the hwsim_new_radio_nl() function in the simulated radio testing tool driver for mac80211, allowing a local user to cause a denial of service.

CVE-2018-8781

Eyal Itkin reported that the udl (DisplayLink) driver's mmap operation did not properly range-check the file offset. A local user with access to a udl framebuffer device could exploit this to overwrite kernel memory, leading to privilege escalation.

CVE-2018-8822

Dr Silvio Cesare of InfoSect reported that the ncpfs client implementation did not validate reply lengths from the server. An ncpfs server could use this to cause a denial of service or remote code execution in the client.

CVE-2018-10323

Wen Xu reported a NULL pointer dereference flaw in the xfs_bmapi_write() function triggered when mounting and operating a crafted xfs filesystem image. A local user able to mount arbitrary filesystems could use this for denial of service.

CVE-2018-1000199

Andy Lutomirski discovered that the ptrace subsystem did not sufficiently validate hardware breakpoint settings. Local users can use this to cause a denial of service, or possibly for privilege escalation, on x86 (amd64 and i386) and possibly other architectures.

For the stable distribution (stretch), these problems have been fixed in version 4.9.88-1.

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/linux