Topic

An update for kernel-rt is now available for Red Hat Enterprise MRG 2.

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.

Description

The kernel-rt packages provide the Real Time Linux Kernel, which enables fine-tuning for systems with extremely high determinism requirements.

Security Fix(es):

• A race condition was found in the Linux kernel, present since v3.14-rc1 through v4.12. The race happens between threads of inotify_handle_event() and vfs_rename() while running the rename operation against the same file. As a result of the race the next slab data or the slab's free list pointer can be corrupted with attacker-controlled data, which may lead to the privilege escalation. (CVE-2017-7533, Important)
• It was found that the NFSv4 server in the Linux kernel did not properly validate layout type when processing NFSv4 pNFS LAYOUTGET and GETDEVICEINFO operands. A remote attacker could use this flaw to soft-lockup the system and thus cause denial of service. (CVE-2017-8797, Important)

This update also fixes multiple Moderate and Low impact security issues:

CVE-2017-8797 CVE-2015-8839 CVE-2016-9576 CVE-2016-7042 CVE-2016-7097 CVE-2016-8645 CVE-2016-9576 CVE-2016-9806 CVE-2016-10088 CVE-2017-2671 CVE-2017-5970 CVE-2017-6001 CVE-2017-6951 CVE-2017-7187 CVE-2017-7889 CVE-2017-8890 CVE-2017-9074 CVE-2017-8890 CVE-2017-9075 CVE-2017-8890 CVE-2017-9076 CVE-2017-8890 CVE-2017-9077 CVE-2016-9604 CVE-2016-9685

Documentation for these issues are available from the Technical Notes document linked to in the References section.

Red Hat would like to thank Leilei Lin (Alibaba Group), Fan Wu (The University of Hong Kong), and Shixiong Zhao (The University of Hong Kong) for reporting CVE-2017-7533 and Marco Grassi for reporting CVE-2016-8645. The CVE-2016-7042 issue was discovered by Ondrej Kozina (Red Hat); the CVE-2016-7097 issue was discovered by Andreas Gruenbacher (Red Hat) and Jan Kara (SUSE); the CVE-2016-9604 issue was discovered by David Howells (Red Hat); and the CVE-2016-9685 issue was discovered by Qian Cai (Red Hat).

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.

Affected Products

• MRG Realtime 2 x86_64

Fixes

• BZ - 1323577 - CVE-2015-8839 kernel: ext4 filesystem page fault race condition with fallocate call.
• BZ - 1368938 - CVE-2016-7097 kernel: Setting a POSIX ACL via setxattr doesn't clear the setgid bit
• BZ - 1373966 - CVE-2016-7042 kernel: Stack corruption while reading /proc/keys when gcc stack protector is enabled
• BZ - 1389433 - CVE-2016-9604 kernel: security: The built-in keyrings for security tokens can be joined as a session and then modified by the root user
• BZ - 1393904 - CVE-2016-8645 kernel: a BUG() statement can be hit in net/ipv4/tcp_input.c
• BZ - 1396941 - CVE-2016-9685 kernel: Memory leaks in xfs_attr_list.c error paths
• BZ - 1401502 - CVE-2016-9806 kernel: netlink: double-free in netlink_dump
• BZ - 1403145 - CVE-2016-9576 kernel: Use after free in SCSI generic device interface
• BZ - 1412210 - CVE-2016-10088 kernel: Use after free in SCSI generic device interface (CVE-2016-9576 regression)
• BZ - 1421638 - CVE-2017-5970 kernel: ipv4: Invalid IP options could cause skb->dst drop
• BZ - 1422825 - CVE-2017-6001 kernel: Race condition between multiple sys_perf_event_open() calls
• BZ - 1433252 - CVE-2017-6951 kernel: NULL pointer dereference in keyring_search_aux function
• BZ - 1434327 - CVE-2017-7187 kernel: scsi: Stack-based buffer overflow in sg_ioctl function
• BZ - 1436649 - CVE-2017-2671 kernel: ping socket / AF_LLC connect() sin_family race
• BZ - 1444493 - CVE-2017-7889 kernel: mm subsystem does not properly enforce the CONFIG_STRICT_DEVMEM protection mechanism
• BZ - 1450972 - CVE-2017-8890 kernel: Double free in the inet_csk_clone_lock function in net/ipv4/inet_connection_sock.c
• BZ - 1452679 - CVE-2017-9074 kernel: net: IPv6 fragmentation implementation of nexthdr field may be associated with an invalid option
• BZ - 1452688 - CVE-2017-9076 kernel: net: IPv6 DCCP implementation mishandles inheritance
• BZ - 1452691 - CVE-2017-9075 kernel: net: sctp_v6_create_accept_sk function mishandles inheritance
• BZ - 1452744 - CVE-2017-9077 kernel: net: tcp_v6_syn_recv_sock function mishandles inheritance
• BZ - 1466329 - CVE-2017-8797 kernel: NFSv4 server does not properly validate layout type when processing NFSv4 pNFS LAYOUTGET operand
• BZ - 1468283 - CVE-2017-7533 kernel: a race between inotify_handle_event() and sys_rename()
• BZ - 1479016 - update the MRG 2.5.z 3.10 kernel-rt sources

CVEs

• CVE-2015-8839
• CVE-2016-7042
• CVE-2016-7097
• CVE-2016-8645
• CVE-2016-9576
• CVE-2016-9604
• CVE-2016-9685
• CVE-2016-9806
• CVE-2016-10088
• CVE-2016-10741
• CVE-2017-2671
• CVE-2017-5551
• CVE-2017-5970
• CVE-2017-6001
• CVE-2017-6951
• CVE-2017-7187
• CVE-2017-7495
• CVE-2017-7533
• CVE-2017-7889
• CVE-2017-8797
• CVE-2017-8890
• CVE-2017-9074
• CVE-2017-9075
• CVE-2017-9076
• CVE-2017-9077

References

• https://access.redhat.com/security/updates/classification/#important
• https://access.redhat.com/articles/3173821