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 use-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
Several vulnerabilities have been discovered in the Linux kernel that may lead to a privilege escalation, denial of service or information leaks.
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.
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.
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.
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.
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.
Jun He reported a use-after-free flaw in the Hisilicon HNS ethernet driver. A local user could use this for denial of service.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
Seunghun Han reported a race condition in the x86 MCE (Machine Check Exception) driver. This is unlikely to have any security impact.
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.
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.
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.
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.
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
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