|Related CVEs||CVE-2017-18509 CVE-2018-20836 CVE-2019-1125 CVE-2019-3900 CVE-2019-10207 CVE-2019-10638 CVE-2019-13631 CVE-2019-14283 CVE-2019-14284|
Several vulnerabilities have been discovered in the Linux kernel that may lead to a privilege escalation, denial of service or information leaks.
Denis Andzakovic reported a missing type check in the IPv4 multicast routing implementation. A user with the CAP_NET_ADMIN capability (in any user namespace) could use this for denial-of-service (memory corruption or crash) or possibly for privilege escalation.
chenxiang reported a race condition in libsas, the kernel subsystem supporting Serial Attached SCSI (SAS) devices, which could lead to a use-after-free. It is not clear how this might be exploited.
It was discovered that most x86 processors could speculatively skip a conditional SWAPGS instruction used when entering the kernel from user mode, and/or could speculatively execute it when it should be skipped. This is a subtype of Spectre variant 1, which could allow local users to obtain sensitive information from the kernel or other processes. It has been mitigated by using memory barriers to limit speculative execution. Systems using an i386 kernel are not affected as the kernel does not use SWAPGS.
It was discovered that vhost drivers did not properly control the amount of work done to service requests from guest VMs. A malicious guest could use this to cause a denial-of-service (unbounded CPU usage) on the host.
The syzkaller tool found a potential null dereference in various drivers for UART-attached Bluetooth adapters. A local user with access to a pty device or other suitable tty device could use this for denial-of-service (BUG/oops).
Amit Klein and Benny Pinkas discovered that the generation of IP packet IDs used a weak hash function, "jhash". This could enable tracking individual computers as they communicate with different remote servers and from different networks. The "siphash" function is now used instead.
It was discovered that the gtco driver for USB input tablets could overrun a stack buffer with constant data while parsing the device's descriptor. A physically present user with a specially constructed USB device could use this to cause a denial-of-service (BUG/oops), or possibly for privilege escalation.
The syzkaller tool found a missing bounds check in the floppy disk driver. A local user with access to a floppy disk device, with a disk present, could use this to read kernel memory beyond the I/O buffer, possibly obtaining sensitive information.
The syzkaller tool found a potential division-by-zero in the floppy disk driver. A local user with access to a floppy disk device could use this for denial-of-service (oops).
(CVE ID not yet assigned)
Denis Andzakovic reported a possible use-after-free in the TCP sockets implementation. A local user could use this for denial-of-service (memory corruption or crash) or possibly for privilege escalation.
(CVE ID not yet assigned)
The netfilter conntrack subsystem used kernel addresses as user-visible IDs, which could make it easier to exploit other security vulnerabilities.
Julien Grall reported that Linux does not limit the amount of memory which a domain will attempt to balloon out, nor limits the amount of "foreign / grant map" memory which any individual guest can consume, leading to denial of service conditions (for host or guests).
For Debian 7 Wheezy, these problems have been fixed in version 3.16.72-1~deb7u1.
We recommend that you upgrade your linux packages.
Further information about Extended LTS security advisories can be found at: https://deb.freexian.com/extended-lts/