9.3 - RHSA-2017:1308

Problem Description:

An update for kernel is now available for Red Hat Enterprise Linux 7.

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.

2. Relevant releases/architectures:

Red Hat Enterprise Linux Client (v. 7) - noarch, x86_64 Red Hat Enterprise Linux Client Optional (v. 7) - x86_64 Red Hat Enterprise Linux ComputeNode (v. 7) - noarch, x86_64 Red Hat Enterprise Linux ComputeNode Optional (v. 7) - x86_64 Red Hat Enterprise Linux Server (v. 7) - noarch, ppc64, ppc64le, s390x, x86_64 Red Hat Enterprise Linux Server Optional (v. 7) - ppc64, ppc64le, x86_64 Red Hat Enterprise Linux Workstation (v. 7) - noarch, x86_64 Red Hat Enterprise Linux Workstation Optional (v. 7) - x86_64

3. Description:

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

Security Fix(es):

* It was found that the packet_set_ring() function of the Linux kernel's networking implementation did not properly validate certain block-size data. A local attacker with CAP_NET_RAW capability could use this flaw to trigger a buffer overflow, resulting in the crash of the system. Due to the nature of the flaw, privilege escalation cannot be fully ruled out. (CVE-2017-7308, Important)

* Mounting a crafted EXT4 image read-only leads to an attacker controlled memory corruption and SLAB-Out-of-Bounds reads. (CVE-2016-10208, Moderate)

* A flaw was found in the Linux kernel's implementation of seq_file where a local attacker could manipulate memory in the put() function pointer. This could lead to memory corruption and possible privileged escalation. (CVE-2016-7910, Moderate)

* A vulnerability was found in the Linux kernel. An unprivileged local user could trigger oops in shash_async_export() by attempting to force the in-kernel hashing algorithms into decrypting an empty data set. (CVE-2016-8646, Moderate)

* It was reported that with Linux kernel, earlier than version v4.10-rc8, an application may trigger a BUG_ON in sctp_wait_for_sndbuf if the socket tx buffer is full, a thread is waiting on it to queue more data, and meanwhile another thread peels off the association being used by the first thread. (CVE-2017-5986, Moderate)

Red Hat would like to thank Igor Redko (Virtuozzo kernel team) for reporting CVE-2016-8646.

Additional Changes:

This update also fixes several bugs and adds various enhancements. Documentation for these changes is available from the Technical Notes document linked to in the References section.

4. Solution:

For details on how to apply this update, which includes the changes described in this advisory, refer to:

https://access.redhat.com/articles/11258

The system must be rebooted for this update to take effect.

5. Bugs fixed (https://bugzilla.redhat.com/):

1388821 - CVE-2016-8646 kernel: Oops in shash_async_export() 1395190 - CVE-2016-10208 kernel: EXT4 memory corruption / SLAB out-of-bounds read 1399727 - CVE-2016-7910 kernel: Use after free in seq file 1420276 - CVE-2017-5986 kernel: Reachable BUG_ON from userspace in sctp_wait_for_sndbuf 1437404 - CVE-2017-7308 kernel: net/packet: overflow in check for priv area size