[SECURITY] [DSA 4495-1] linux security update
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Debian Security Advisory DSA-4495-1 email@example.com
https://www.debian.org/security/ Ben Hutchings
August 10, 2019 https://www.debian.org/security/faq
Package : linux
CVE ID : CVE-2018-20836 CVE-2019-1125 CVE-2019-1999 CVE-2019-10207
CVE-2019-10638 CVE-2019-12817 CVE-2019-12984 CVE-2019-13233
CVE-2019-13631 CVE-2019-13648 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
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
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.
A race condition was discovered in the Android binder driver,
which could lead to a use-after-free. If this driver is loaded, a
local user might be able to use this for denial-of-service
(memory corruption) or for privilege escalation.
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 on the PowerPC (ppc64el) architecture, the
hash page table (HPT) code did not correctly handle fork() in a
process with memory mapped at addresses above 512 TiB. This could
lead to a use-after-free in the kernel, or unintended sharing of
memory between user processes. A local user could use this for
privilege escalation. Systems using the radix MMU, or a custom
kernel with a 4 KiB page size, are not affected.
It was discovered that the NFC protocol implementation did not
properly validate a netlink control message, potentially leading
to a null pointer dereference. A local user on a system with an
NFC interface could use this for denial-of-service (BUG/oops).
Jann Horn discovered a race condition on the x86 architecture,
in use of the LDT. This could lead to a use-after-free. A
local user could possibly use this for denial-of-service.
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.
Praveen Pandey reported that on PowerPC (ppc64el) systems without
Transactional Memory (TM), the kernel would still attempt to
restore TM state passed to the sigreturn() system call. A local
user could use this for denial-of-service (oops).
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).
For the stable distribution (buster), these problems have been fixed in
For the oldstable distribution (stretch), these problems will be fixed
We recommend that you upgrade your linux packages.
For the detailed security status of linux please refer to
its security tracker page at:
Further information about Debian Security Advisories, how to apply
these updates to your system and frequently asked questions can be
found at: https://www.debian.org/security/
Mailing list: firstname.lastname@example.org
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