An update for kernel is now available for Red Hat Enterprise Linux 6.

Red Hat Product Security has rated this update as having a security impact of Important. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) in the References section.

The kernel packages contain the Linux kernel, the core of any Linux operating system.

Security Fix(es) :

* An industry-wide issue was found in the way many modern microprocessor designs have implemented speculative execution of Load & Store instructions (a commonly used performance optimization). It relies on the presence of a precisely-defined instruction sequence in the privileged code as well as the fact that memory read from address to which a recent memory write has occurred may see an older value and subsequently cause an update into the microprocessor's data cache even for speculatively executed instructions that never actually commit (retire). As a result, an unprivileged attacker could use this flaw to read privileged memory by conducting targeted cache side-channel attacks. (CVE-2018-3639, PowerPC)

* kernel: net/packet: overflow in check for priv area size (CVE-2017-7308)

* kernel: AIO interface didn't use rw_verify_area() for checking mandatory locking on files and size of access (CVE-2012-6701)

* kernel: AIO write triggers integer overflow in some protocols (CVE-2015-8830)

* kernel: NULL pointer dereference via keyctl (CVE-2016-8650)

* kernel: ping socket / AF_LLC connect() sin_family race (CVE-2017-2671)

* kernel: Race condition between multiple sys_perf_event_open() calls (CVE-2017-6001)

* kernel: Incorrect error handling in the set_mempolicy and mbind compat syscalls in mm/mempolicy.c (CVE-2017-7616)

* kernel: mm subsystem does not properly enforce the CONFIG_STRICT_DEVMEM protection mechanism (CVE-2017-7889)

* kernel: Double free in the inet_csk_clone_lock function in net/ipv4/ inet_connection_sock.c (CVE-2017-8890)

* kernel: net: sctp_v6_create_accept_sk function mishandles inheritance (CVE-2017-9075)

* kernel: net: IPv6 DCCP implementation mishandles inheritance (CVE-2017-9076)

* kernel: net: tcp_v6_syn_recv_sock function mishandles inheritance (CVE-2017-9077)

* kernel: memory leak when merging buffers in SCSI IO vectors (CVE-2017-12190)

* kernel: vfs: BUG in truncate_inode_pages_range() and fuse client (CVE-2017-15121)

* kernel: Race condition in drivers/md/dm.c:dm_get_from_kobject() allows local users to cause a denial of service (CVE-2017-18203)

* kernel: a NULL pointer dereference in net/dccp/output.c:dccp_write_xmit() leads to a system crash (CVE-2018-1130)

* kernel: Missing length check of payload in net/sctp/ sm_make_chunk.c:_sctp_make_chunk() function allows denial of service (CVE-2018-5803)

For more details about the security issue(s), including the impact, a CVSS score, and other related information, refer to the CVE page(s) listed in the References section.

Red Hat would like to thank Ken Johnson (Microsoft Security Response Center) and Jann Horn (Google Project Zero) for reporting CVE-2018-3639; Vitaly Mayatskih for reporting CVE-2017-12190; and Evgenii Shatokhin (Virtuozzo Team) for reporting CVE-2018-1130. The CVE-2017-15121 issue was discovered by Miklos Szeredi (Red Hat).

Additional Changes :

For detailed information on changes in this release, see the Red Hat Enterprise Linux 6.10 Release Notes and Red Hat Enterprise Linux 6.10 Technical Notes linked from the References section.

The remote Oracle Linux 6 host has packages installed that are affected by multiple vulnerabilities as referenced in the ELSA-2018-1854 advisory.

  - The mpi_powm function in lib/mpi/mpi-pow.c in the Linux kernel through 4.8.11 does not ensure that memory     is allocated for limb data, which allows local users to cause a denial of service (stack memory corruption     and panic) via an add_key system call for an RSA key with a zero exponent. (CVE-2016-8650)

  - Race condition in kernel/events/core.c in the Linux kernel before 4.9.7 allows local users to gain     privileges via a crafted application that makes concurrent perf_event_open system calls for moving a     software group into a hardware context. NOTE: this vulnerability exists because of an incomplete fix for     CVE-2016-6786. (CVE-2017-6001)

  - The inet_csk_clone_lock function in net/ipv4/inet_connection_sock.c in the Linux kernel through 4.10.15     allows attackers to cause a denial of service (double free) or possibly have unspecified other impact by     leveraging use of the accept system call. (CVE-2017-8890)

  - The packet_set_ring function in net/packet/af_packet.c in the Linux kernel through 4.10.6 does not     properly validate certain block-size data, which allows local users to cause a denial of service (integer     signedness error and out-of-bounds write), or gain privileges (if the CAP_NET_RAW capability is held), via     crafted system calls. (CVE-2017-7308)

  - The tcp_v6_syn_recv_sock function in net/ipv6/tcp_ipv6.c in the Linux kernel through 4.11.1 mishandles     inheritance, which allows local users to cause a denial of service or possibly have unspecified other     impact via crafted system calls, a related issue to CVE-2017-8890. (CVE-2017-9077)

  - The ping_unhash function in net/ipv4/ping.c in the Linux kernel through 4.10.8 is too late in obtaining a     certain lock and consequently cannot ensure that disconnect function calls are safe, which allows local     users to cause a denial of service (panic) by leveraging access to the protocol value of IPPROTO_ICMP in a     socket system call. (CVE-2017-2671)

  - Incorrect error handling in the set_mempolicy and mbind compat syscalls in mm/mempolicy.c in the Linux     kernel through 4.10.9 allows local users to obtain sensitive information from uninitialized stack data by     triggering failure of a certain bitmap operation. (CVE-2017-7616)

  - The mm subsystem in the Linux kernel through 3.2 does not properly enforce the CONFIG_STRICT_DEVMEM     protection mechanism, which allows local users to read or write to kernel memory locations in the first     megabyte (and bypass slab-allocation access restrictions) via an application that opens the /dev/mem file,     related to arch/x86/mm/init.c and drivers/char/mem.c. (CVE-2017-7889)

  - The dccp_v6_request_recv_sock function in net/dccp/ipv6.c in the Linux kernel through 4.11.1 mishandles     inheritance, which allows local users to cause a denial of service or possibly have unspecified other     impact via crafted system calls, a related issue to CVE-2017-8890. (CVE-2017-9076)

  - The sctp_v6_create_accept_sk function in net/sctp/ipv6.c in the Linux kernel through 4.11.1 mishandles     inheritance, which allows local users to cause a denial of service or possibly have unspecified other     impact via crafted system calls, a related issue to CVE-2017-8890. (CVE-2017-9075)

  - The bio_map_user_iov and bio_unmap_user functions in block/bio.c in the Linux kernel before 4.13.8 do     unbalanced refcounting when a SCSI I/O vector has small consecutive buffers belonging to the same page.
    The bio_add_pc_page function merges them into one, but the page reference is never dropped. This causes a     memory leak and possible system lockup (exploitable against the host OS by a guest OS user, if a SCSI disk     is passed through to a virtual machine) due to an out-of-memory condition. (CVE-2017-12190)

  - A non-privileged user is able to mount a fuse filesystem on RHEL 6 or 7 and crash a system if an     application punches a hole in a file that does not end aligned to a page boundary. (CVE-2017-15121)

  - The dm_get_from_kobject function in drivers/md/dm.c in the Linux kernel before 4.14.3 allow local users to     cause a denial of service (BUG) by leveraging a race condition with __dm_destroy during creation and     removal of DM devices. (CVE-2017-18203)

  - Systems with microprocessors utilizing speculative execution and speculative execution of memory reads     before the addresses of all prior memory writes are known may allow unauthorized disclosure of information     to an attacker with local user access via a side-channel analysis, aka Speculative Store Bypass (SSB),     Variant 4. (CVE-2018-3639)

  - Integer overflow in fs/aio.c in the Linux kernel before 3.4.1 allows local users to cause a denial of     service or possibly have unspecified other impact via a large AIO iovec. (CVE-2012-6701)

  - Integer overflow in the aio_setup_single_vector function in fs/aio.c in the Linux kernel 4.0 allows local     users to cause a denial of service or possibly have unspecified other impact via a large AIO iovec. NOTE:
    this vulnerability exists because of a CVE-2012-6701 regression. (CVE-2015-8830)

  - In the Linux Kernel before version 4.15.8, 4.14.25, 4.9.87, 4.4.121, 4.1.51, and 3.2.102, an error in the
    _sctp_make_chunk() function (net/sctp/sm_make_chunk.c) when handling SCTP packets length can be     exploited to cause a kernel crash. (CVE-2018-5803)

  - Linux kernel before version 4.16-rc7 is vulnerable to a null pointer dereference in dccp_write_xmit()     function in net/dccp/output.c in that allows a local user to cause a denial of service by a number of     certain crafted system calls. (CVE-2018-1130)

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

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

CVE-2017-7487

Li Qiang reported a reference counter leak in the ipxitf_ioctl function which may result into a use-after-free vulnerability, triggerable when a IPX interface is configured.

CVE-2017-7645

Tuomas Haanpaa and Matti Kamunen from Synopsys Ltd discovered that the NFSv2 and NFSv3 server implementations are vulnerable to an out-of-bounds memory access issue while processing arbitrarily long arguments sent by NFSv2/NFSv3 PRC clients, leading to a denial of service.

CVE-2017-7895

Ari Kauppi from Synopsys Ltd discovered that the NFSv2 and NFSv3 server implementations do not properly handle payload bounds checking of WRITE requests. A remote attacker with write access to a NFS mount can take advantage of this flaw to read chunks of arbitrary memory from both kernel-space and user-space.

CVE-2017-8890

It was discovered that the net_csk_clone_lock() function allows a remote attacker to cause a double free leading to a denial of service or potentially have other impact.

CVE-2017-8924

Johan Hovold found that the io_ti USB serial driver could leak sensitive information if a malicious USB device was connected.

CVE-2017-8925

Johan Hovold found a reference counter leak in the omninet USB serial driver, resulting in a use-after-free vulnerability. This can be triggered by a local user permitted to open tty devices.

CVE-2017-9074

Andrey Konovalov reported that the IPv6 fragmentation implementation could read beyond the end of a packet buffer. A local user or guest VM might be able to use this to leak sensitive information or to cause a denial of service (crash).

CVE-2017-9075

Andrey Konovalov reported that the SCTP/IPv6 implementation wrongly initialised address lists on connected sockets, resulting in a use-after-free vulnerability, a similar issue to CVE-2017-8890. This can be triggered by any local user.

CVE-2017-9076 / CVE-2017-9077 Cong Wang found that the TCP/IPv6 and DCCP/IPv6 implementations wrongly initialised address lists on connected sockets, a similar issue to CVE-2017-9075.

CVE-2017-9242

Andrey Konovalov reported a packet buffer overrun in the IPv6 implementation. A local user could use this for denial of service (memory corruption; crash) and possibly for privilege escalation.

CVE-2017-1000364

The Qualys Research Labs discovered that the size of the stack guard page is not sufficiently large. The stack-pointer can jump over the guard-page and moving from the stack into another memory region without accessing the guard-page. In this case no page-fault exception is raised and the stack extends into the other memory region. An attacker can exploit this flaw for privilege escalation.

The default stack gap protection is set to 256 pages and can be configured via the stack_guard_gap kernel parameter on the kernel command line.

Further details can be found at https://www.qualys.com/2017/06/19/stack-clash/stack-clash.tx t

For Debian 7 'Wheezy', this problem has been fixed in version 3.2.89-2.

For Debian 8 'Jessie', this problem has been fixed in version 3.16.43-2+deb8u2.

For Debian 9 'Stretch', this problem has been fixed in version 4.9.30-2+deb9u2.

We recommend that you upgrade your linux packages.

NOTE: Tenable Network Security has extracted the preceding description block directly from the DLA security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

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

  - CVE-2017-7487     Li Qiang reported a reference counter leak in the     ipxitf_ioctl function which may result into a     use-after-free vulnerability, triggerable when a IPX     interface is configured.

  - CVE-2017-7645     Tuomas Haanpaa and Matti Kamunen from Synopsys Ltd     discovered that the NFSv2 and NFSv3 server     implementations are vulnerable to an out-of-bounds     memory access issue while processing arbitrarily long     arguments sent by NFSv2/NFSv3 PRC clients, leading to a     denial of service.

  - CVE-2017-7895     Ari Kauppi from Synopsys Ltd discovered that the NFSv2     and NFSv3 server implementations do not properly handle     payload bounds checking of WRITE requests. A remote     attacker with write access to a NFS mount can take     advantage of this flaw to read chunks of arbitrary     memory from both kernel-space and user-space.

  - CVE-2017-8064     Arnd Bergmann found that the DVB-USB core misused the     device logging system, resulting in a use-after-free     vulnerability, with unknown security impact.

  - CVE-2017-8890     It was discovered that the net_csk_clone_lock() function     allows a remote attacker to cause a double free leading     to a denial of service or potentially have other impact.

  - CVE-2017-8924     Johan Hovold found that the io_ti USB serial driver     could leak sensitive information if a malicious USB     device was connected.

  - CVE-2017-8925     Johan Hovold found a reference counter leak in the     omninet USB serial driver, resulting in a use-after-free     vulnerability. This can be triggered by a local user     permitted to open tty devices.

  - CVE-2017-9074     Andrey Konovalov reported that the IPv6 fragmentation     implementation could read beyond the end of a packet     buffer. A local user or guest VM might be able to use     this to leak sensitive information or to cause a denial     of service (crash).

  - CVE-2017-9075     Andrey Konovalov reported that the SCTP/IPv6     implementation wrongly initialised address lists on     connected sockets, resulting in a use-after-free     vulnerability, a similar issue to CVE-2017-8890. This     can be triggered by any local user.

  - CVE-2017-9076 / CVE-2017-9077     Cong Wang found that the TCP/IPv6 and DCCP/IPv6     implementations wrongly initialised address lists on     connected sockets, a similar issue to CVE-2017-9075.

  - CVE-2017-9242     Andrey Konovalov reported a packet buffer overrun in the     IPv6 implementation. A local user could use this for     denial of service (memory corruption; crash) and     possibly for privilege escalation.

  - CVE-2017-1000364     The Qualys Research Labs discovered that the size of the     stack guard page is not sufficiently large. The     stack-pointer can jump over the guard-page and moving     from the stack into another memory region without     accessing the guard-page. In this case no page-fault     exception is raised and the stack extends into the other     memory region. An attacker can exploit this flaw for     privilege escalation.

  The default stack gap protection is set to 256 pages and can be   configured via the stack_guard_gap kernel parameter on the kernel   command line.

  Further details can be found at   https://www.qualys.com/2017/06/19/stack-clash/stack-clash.txt

It was discovered that the stack guard page for processes in the Linux kernel was not sufficiently large enough to prevent overlapping with the heap. An attacker could leverage this with another vulnerability to execute arbitrary code and gain administrative privileges (CVE-2017-1000364)

Roee Hay discovered that the parallel port printer driver in the Linux kernel did not properly bounds check passed arguments. A local attacker with write access to the kernel command line arguments could use this to execute arbitrary code. (CVE-2017-1000363)

A double free bug was discovered in the IPv4 stack of the Linux kernel. An attacker could use this to cause a denial of service (system crash). (CVE-2017-8890)

Andrey Konovalov discovered an IPv6 out-of-bounds read error in the Linux kernel's IPv6 stack. A local attacker could cause a denial of service or potentially other unspecified problems. (CVE-2017-9074)

Andrey Konovalov discovered a flaw in the handling of inheritance in the Linux kernel's IPv6 stack. A local user could exploit this issue to cause a denial of service or possibly other unspecified problems.
(CVE-2017-9075)

It was discovered that dccp v6 in the Linux kernel mishandled inheritance. A local attacker could exploit this issue to cause a denial of service or potentially other unspecified problems.
(CVE-2017-9076)

It was discovered that the transmission control protocol (tcp) v6 in the Linux kernel mishandled inheritance. A local attacker could exploit this issue to cause a denial of service or potentially other unspecified problems. (CVE-2017-9077)

Jann Horn discovered that bpf in Linux kernel does not restrict the output of the print_bpf_insn function. A local attacker could use this to obtain sensitive address information. (CVE-2017-9150)

It was discovered that the IPv6 stack was doing over write consistency check after the data was actually overwritten. A local attacker could exploit this flaw to cause a denial of service (system crash).
(CVE-2017-9242).

Note that Tenable Network Security has extracted the preceding description block directly from the Ubuntu security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

It was discovered that a use-after-free flaw existed in the filesystem encryption subsystem in the Linux kernel. A local attacker could use this to cause a denial of service (system crash). (CVE-2017-7374)

It was discovered that the stack guard page for processes in the Linux kernel was not sufficiently large enough to prevent overlapping with the heap. An attacker could leverage this with another vulnerability to execute arbitrary code and gain administrative privileges (CVE-2017-1000364)

Roee Hay discovered that the parallel port printer driver in the Linux kernel did not properly bounds check passed arguments. A local attacker with write access to the kernel command line arguments could use this to execute arbitrary code. (CVE-2017-1000363)

Ingo Molnar discovered that the VideoCore DRM driver in the Linux kernel did not return an error after detecting certain overflows. A local attacker could exploit this issue to cause a denial of service (OOPS). (CVE-2017-5577)

A double free bug was discovered in the IPv4 stack of the Linux kernel. An attacker could use this to cause a denial of service (system crash). (CVE-2017-8890)

Andrey Konovalov discovered an IPv6 out-of-bounds read error in the Linux kernel's IPv6 stack. A local attacker could cause a denial of service or potentially other unspecified problems. (CVE-2017-9074)

Andrey Konovalov discovered a flaw in the handling of inheritance in the Linux kernel's IPv6 stack. A local user could exploit this issue to cause a denial of service or possibly other unspecified problems.
(CVE-2017-9075)

It was discovered that dccp v6 in the Linux kernel mishandled inheritance. A local attacker could exploit this issue to cause a denial of service or potentially other unspecified problems.
(CVE-2017-9076)

It was discovered that the transmission control protocol (tcp) v6 in the Linux kernel mishandled inheritance. A local attacker could exploit this issue to cause a denial of service or potentially other unspecified problems. (CVE-2017-9077)

It was discovered that the IPv6 stack was doing over write consistency check after the data was actually overwritten. A local attacker could exploit this flaw to cause a denial of service (system crash).
(CVE-2017-9242).

Note that Tenable Network Security has extracted the preceding description block directly from the Ubuntu security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

The remote Ubuntu 16.04 LTS host has a package installed that is affected by multiple vulnerabilities as referenced in the USN-3344-1 advisory.

  - Linux drivers/char/lp.c Out-of-Bounds Write. Due to a missing bounds check, and the fact that parport_ptr     integer is static, a 'secure boot' kernel command line adversary (can happen due to bootloader vulns, e.g.
    Google Nexus 6's CVE-2016-10277, where due to a vulnerability the adversary has partial control over the     command line) can overflow the parport_nr array in the following code, by appending many (>LP_NO)     'lp=none' arguments to the command line. (CVE-2017-1000363)

  - The ipxitf_ioctl function in net/ipx/af_ipx.c in the Linux kernel through 4.11.1 mishandles reference     counts, which allows local users to cause a denial of service (use-after-free) or possibly have     unspecified other impact via a failed SIOCGIFADDR ioctl call for an IPX interface. (CVE-2017-7487)

  - The inet_csk_clone_lock function in net/ipv4/inet_connection_sock.c in the Linux kernel through 4.10.15     allows attackers to cause a denial of service (double free) or possibly have unspecified other impact by     leveraging use of the accept system call. (CVE-2017-8890)

  - The IPv6 fragmentation implementation in the Linux kernel through 4.11.1 does not consider that the     nexthdr field may be associated with an invalid option, which allows local users to cause a denial of     service (out-of-bounds read and BUG) or possibly have unspecified other impact via crafted socket and send     system calls. (CVE-2017-9074)

  - The sctp_v6_create_accept_sk function in net/sctp/ipv6.c in the Linux kernel through 4.11.1 mishandles     inheritance, which allows local users to cause a denial of service or possibly have unspecified other     impact via crafted system calls, a related issue to CVE-2017-8890. (CVE-2017-9075)

  - The dccp_v6_request_recv_sock function in net/dccp/ipv6.c in the Linux kernel through 4.11.1 mishandles     inheritance, which allows local users to cause a denial of service or possibly have unspecified other     impact via crafted system calls, a related issue to CVE-2017-8890. (CVE-2017-9076)

  - The tcp_v6_syn_recv_sock function in net/ipv6/tcp_ipv6.c in the Linux kernel through 4.11.1 mishandles     inheritance, which allows local users to cause a denial of service or possibly have unspecified other     impact via crafted system calls, a related issue to CVE-2017-8890. (CVE-2017-9077)

  - The __ip6_append_data function in net/ipv6/ip6_output.c in the Linux kernel through 4.11.3 is too late in     checking whether an overwrite of an skb data structure may occur, which allows local users to cause a     denial of service (system crash) via crafted system calls. (CVE-2017-9242)

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

ID	Name	Product	Family	Published	Updated	Severity
110645	CentOS 6 : kernel (CESA-2018:1854) (Spectre)	Nessus	CentOS Local Security Checks	6/22/2018	4/5/2019	critical
110701	Oracle Linux 6 : kernel (ELSA-2018-1854)	Nessus	Oracle Linux Local Security Checks	6/27/2018	9/8/2021	high
100876	Debian DLA-993-2 : linux regression update (Stack Clash)	Nessus	Debian Local Security Checks	6/20/2017	1/11/2021	critical
100877	Debian DSA-3886-1 : linux - security update (Stack Clash)	Nessus	Debian Local Security Checks	6/20/2017	1/4/2021	critical
100923	Ubuntu 17.04 : linux-meta-raspi2, linux-raspi2 vulnerabilities (USN-3325-1) (Stack Clash)	Nessus	Ubuntu Local Security Checks	6/20/2017	1/12/2023	high
100924	Ubuntu 16.10 : linux, linux-meta vulnerabilities (USN-3326-1) (Stack Clash)	Nessus	Ubuntu Local Security Checks	6/20/2017	1/12/2023	high
101154	Ubuntu 16.04 LTS : Linux kernel vulnerabilities (USN-3344-1)	Nessus	Ubuntu Local Security Checks	6/30/2017	1/9/2024	high

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