Advisories ยป MGASA-2018-0341

Updated kernel-linus packages fix security vulnerabilities

Publication date: 15 Aug 2018
Type: security
Affected Mageia releases : 6
CVE: CVE-2018-1087 , CVE-2018-1118 , CVE-2018-5390 , CVE-2018-6412 , CVE-2018-8897 , CVE-2018-10853 , CVE-2018-10840 , CVE-2018-10876 , CVE-2018-10877 , CVE-2018-10879 , CVE-2018-10880 , CVE-2018-10881 , CVE-2018-10882 , CVE-2018-10883 , CVE-2018-11412 , CVE-2018-12904 , CVE-2018-13405 , CVE-2018-14678

Description

This kernel-linus update is based on the upstream 4.14.62 and fixes atleast
the following security issues:

kernel KVM before versions kernel 4.16, kernel 4.16-rc7, kernel 4.17-rc1,
kernel 4.17-rc2 and kernel 4.17-rc3 is vulnerable to a flaw in the way the
Linux kernel's KVM hypervisor handled exceptions delivered after a stack
switch operation via Mov SS or Pop SS instructions. During the stack switch
operation, the processor did not deliver interrupts and exceptions, rather
they are delivered once the first instruction after the stack switch is
executed. An unprivileged KVM guest user could use this flaw to crash the
guest or, potentially, escalate their privileges in the guest
(CVE-2018-1087).

Linux kernel vhost since version 4.8 does not properly initialize memory in
messages passed between virtual guests and the host operating system in the
vhost/vhost.c:vhost_new_msg() function. This can allow local privileged
users to read some kernel memory contents when reading from the
/dev/vhost-net device file (CVE-2018-1118).

Security researchers from FICORA have identified a remote denial of
service attack against the Linux kernel caused by inefficient
implementation of TCP segment reassembly, named "SegmentSmack".
A remote attacker could consume a lot of CPU resources in the kernel
networking stack with just a low bandwidth or single host attack by
using lots of small TCP segments packets. Usually large botnets are
needed for similar effect. The rate needed for this denial of service
attack to be effective is several magnitudes lower than the usual
packet processing capability of the machine, as the attack exploits
worst case behaviour of existing algorithms (CVE-2018-5390).
In the function sbusfb_ioctl_helper() in drivers/video/fbdev/sbuslib.c
in the Linux kernel through 4.15, an integer signedness error allows
arbitrary information leakage for the FBIOPUTCMAP_SPARC and
FBIOGETCMAP_SPARC commands (CVE-2018-6412).

In some circumstances, some operating systems or hypervisors may not expect
or properly handle an Intel architecture hardware debug exception. The error
appears to be due to developer interpretation of existing documentation for
certain Intel architecture interrupt/exception instructions, namely MOV SS
and POP SS. An authenticated attacker may be able to read sensitive data in
memory or control low-level operating system functions (CVE-2018-8897).

Linux kernel is vulnerable to a heap-based buffer overflow in the 
fs/ext4/xattr.c:ext4_xattr_set_entry() function. An attacker could exploit
this by operating on a mounted crafted ext4 image (CVE-2018-10840).

The kvm functions that were used in the emulation of fxrstor, fxsave,
sgdt and sidt were originally meant for task switching, and as such they
did not check privilege levels. This allowed guest userspace to guest
kernel write (CVE-2018-10853).

A flaw was found in Linux kernel ext4 File System. A use-after-free in
ext4_ext_remove_space() when mounting and operating a crafted ext4 image
(CVE-2018-10876).

Linux kernel ext4 filesystem is vulnerable to an out-of-bound access in the
ext4_ext_drop_refs() function when operating on a crafted ext4 filesystem
image (CVE-2018-10877).

A flaw was found in Linux kernel ext4 filesystem. A local user can cause a
use-after-free in ext4_xattr_set_entry function and so a denial of service
or possibly unspecified other impact by when renaming a file in a crafted
ext4 filesystem image (CVE-2018-10879).

A flaw was found in Linux kernel ext4 filesystem code. A stack-out-of-bounds
write in ext4_update_inline_data() is possible when mounting and writing to
a crafted ext4 image. An attacker could use this to cause  a system crash
and a denial of service (CVE-2018-10880).

A flaw was found in Linux kernel ext4 filesystem. A local user can cause an
out-of-bound access in ext4_get_group_info function and so a denial of
service and a system crash by mounting and operating on a crafted ext4
filesystem image (CVE-2018-10881).

A flaw was found in Linux kernel ext4 File System. An out-of-bound write
when unmounting a crafted ext4 image in fs/jbd2/transaction.c. An attacker
could use this to cause a denial of service (system crash) (CVE-2018-10882).

A flaw was found in Linux kernel ext4 File System. An out-of-bound write in
jbd2_journal_dirty_metadata() that kernel cannot handle when mounting and
operating a crafted ext4 image. An attacker could use this to cause a
denial of service (system crash) (CVE-2018-10883).

In the Linux kernel 4.13 through 4.16.11, ext4_read_inline_data() in
fs/ext4/inline.c performs a memcpy with an untrusted length value in certain
circumstances involving a crafted filesystem that stores the system.data
extended attribute value in a dedicated inode (CVE-2018-11412).

In arch/x86/kvm/vmx.c in the Linux kernel before 4.17.2, when nested
virtualization is used, local attackers could cause L1 KVM guests to
VMEXIT, potentially allowing privilege escalations and denial of service
attacks due to lack of checking of CPL (CVE-2018-12904).

The inode_init_owner function in fs/inode.c in the Linux kernel through
4.17.4 allows local users to create files with an unintended group
ownership, in a scenario where a directory is SGID to a certain group and
is writable by a user who is not a member of that group. Here, the
non-member can trigger creation of a plain file whose group ownership is
that group. The intended behavior was that the non-member can trigger
creation of a directory (but not a plain file) whose group ownership is
that group. The non-member can escalate privileges by making the plain
file executable and SGID (CVE-2018-13405).

An issue was discovered in the Linux kernel through 4.17.11, as used
in Xen through 4.11.x. The xen_failsafe_callback entry point in 
arch/x86/entry/entry_64.S does not properly maintain RBX, which allows
local users to cause a denial of service (uninitialized memory usage
and system crash). Within Xen, 64-bit x86 PV Linux guest OS users can
trigger a guest OS crash or possibly gain privileges (CVE-2018-14678).

Other changes in this update:
* enable Mellanox5 support (mga#23263)
* enable SMARTPQI support (mga#23305)

For other upstream fixes in this update, see the referenced changelogs.
                

References

SRPMS

6/core