Topic

An update for kernel-alt 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.

Description

The kernel-alt packages provide the Linux kernel version 4.x.

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, aarch64)
• A flaw named SegmentSmack was found in the way the Linux kernel handled specially crafted TCP packets. A remote attacker could use this flaw to trigger time and calculation expensive calls to tcp_collapse_ofo_queue() and tcp_prune_ofo_queue() functions by sending specially modified packets within ongoing TCP sessions which could lead to a CPU saturation and hence a denial of service on the system. Maintaining the denial of service condition requires continuous two-way TCP sessions to a reachable open port, thus the attacks cannot be performed using spoofed IP addresses. (CVE-2018-5390)
• A flaw named FragmentSmack was found in the way the Linux kernel handled reassembly of fragmented IPv4 and IPv6 packets. A remote attacker could use this flaw to trigger time and calculation expensive fragment reassembly algorithm by sending specially crafted packets which could lead to a CPU saturation and hence a denial of service on the system. (CVE-2018-5391)

Space precludes documenting all of the security fixes in this advisory. See the descriptions of the remaining security fixes in the related Knowledge Article:

https://access.redhat.com/articles/3658021

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; Juha-Matti Tilli (Aalto University - Department of Communications and Networking and Nokia Bell Labs) for reporting CVE-2018-5390 and CVE-2018-5391; Qualys Research Labs for reporting CVE-2018-1120; David Rientjes (Google) for reporting CVE-2018-1000200; and Wen Xu for reporting CVE-2018-1092, CVE-2018-1094, and CVE-2018-1095. The CVE-2018-14619 issue was discovered by Florian Weimer (Red Hat) and Ondrej Mosnacek (Red Hat).

Additional Changes:

For detailed information on changes in this release, see the Red Hat Enterprise Linux 7.6 Release Notes linked from the References section.

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

• Red Hat Enterprise Linux for ARM 64 7 aarch64
• Red Hat Enterprise Linux for Power 9 7 ppc64le
• Red Hat Enterprise Linux for IBM System z (Structure A) 7 s390x

Fixes

• BZ - 1516257 - CVE-2017-16648 kernel: Use-after-free in drivers/media/dvb-core/dvb_frontend.c
• BZ - 1528312 - CVE-2017-17805 kernel: Salsa20 encryption algorithm does not correctly handle zero-length inputs allowing local attackers to cause denial-of-service
• BZ - 1528323 - CVE-2017-17806 kernel: HMAC implementation does not validate that the underlying cryptographic hash algorithm is unkeyed allowing local attackers to cause denial-of-service
• BZ - 1533909 - CVE-2018-5344 kernel: drivers/block/loop.c mishandles lo_release serialization allowing denial-of-service
• BZ - 1539508 - CVE-2017-18075 kernel: Mishandled freeing of instances in pcrypt.c can allow a local user to cause a denial of service
• BZ - 1539706 - CVE-2018-5750 kernel: Kernel address information leak in drivers/acpi/sbshc.c:acpi_smbus_hc_add() function potentially allowing KASLR bypass
• BZ - 1541846 - CVE-2018-1000026 kernel: Improper validation in bnx2x network card driver can allow for denial of service attacks via crafted packet
• BZ - 1547824 - CVE-2018-1065 kernel: netfilter: xtables NULL pointer dereference in ip6_tables.c:ip6t_do_table() leading to a crash
• BZ - 1548412 - CVE-2017-13166 kernel: v4l2: disabled memory access protection mechanism allowing privilege escalation
• BZ - 1550142 - CVE-2018-7566 kernel: race condition in snd_seq_write() may lead to UAF or OOB-access
• BZ - 1551051 - CVE-2018-5803 kernel: Missing length check of payload in net/sctp/sm_make_chunk.c:_sctp_make_chunk() function allows denial of service
• BZ - 1551565 - CVE-2017-18208 kernel: Inifinite loop vulnerability in mm/madvise.c:madvise_willneed() function allows local denial of service
• BZ - 1552048 - CVE-2018-1068 kernel: Out-of-bounds write via userland offsets in ebt_entry struct in netfilter/ebtables.c
• BZ - 1553361 - CVE-2018-7757 kernel: Memory leak in the sas_smp_get_phy_events function in drivers/scsi/libsas/sas_expander.c
• BZ - 1560777 - CVE-2018-1092 kernel: NULL pointer dereference in ext4/mballoc.c:ext4_process_freed_data() when mounting crafted ext4 image
• BZ - 1560788 - CVE-2018-1094 kernel: NULL pointer dereference in ext4/xattr.c:ext4_xattr_inode_hash() causes crash with crafted ext4 image
• BZ - 1560793 - CVE-2018-1095 kernel: out-of-bound access in fs/posix_acl.c:get_acl() causes crash with crafted ext4 image
• BZ - 1566890 - CVE-2018-3639 hw: cpu: speculative store bypass
• BZ - 1568744 - CVE-2018-1000200 kernel: NULL pointer dereference on OOM kill of large mlocked process
• BZ - 1571062 - CVE-2018-8781 kernel: Integer overflow in drivers/gpu/drm/udl/udl_fb.c:udl_fb_mmap() can allow attackers to execute code in kernel space
• BZ - 1571623 - CVE-2018-10322 kernel: Invalid pointer dereference in xfs_ilock_attr_map_shared() when mounting crafted xfs image allowing denial of service
• BZ - 1573699 - CVE-2018-1118 kernel: vhost: Information disclosure in vhost/vhost.c:vhost_new_msg()
• BZ - 1575472 - CVE-2018-1120 kernel: fuse-backed file mmap-ed onto process cmdline arguments causes denial of service
• BZ - 1577408 - CVE-2018-10940 kernel: incorrect memory bounds check in drivers/cdrom/cdrom.c
• BZ - 1583210 - CVE-2018-11506 kernel: Stack-based buffer overflow in drivers/scsi/sr_ioctl.c allows denial of service or other unspecified impact
• BZ - 1589324 - CVE-2018-1000204 kernel: Infoleak caused by incorrect handling of the SG_IO ioctl
• BZ - 1590215 - CVE-2018-12232 kernel: NULL pointer dereference if close and fchownat system calls share a socket file descriptor
• BZ - 1590799 - CVE-2018-5848 kernel: buffer overflow in drivers/net/wireless/ath/wil6210/wmi.c:wmi_set_ie() may lead to memory corruption
• BZ - 1596795 - CVE-2018-10877 kernel: out-of-bound access in ext4_ext_drop_refs function with a crafted ext4 image
• BZ - 1596802 - CVE-2018-10878 kernel: out-of-bound write in ext4_init_block_bitmap function with a crafted ext4 image
• BZ - 1596806 - CVE-2018-10879 kernel: use-after-free detected in ext4_xattr_set_entry with a crafted file
• BZ - 1596812 - CVE-2018-10880 kernel: stack-out-of-bounds write in ext4_update_inline_data function
• BZ - 1596828 - CVE-2018-10881 kernel: out-of-bound access in ext4_get_group_info() when mounting and operating a crafted ext4 image
• BZ - 1596842 - CVE-2018-10882 kernel: stack-out-of-bounds write infs/jbd2/transaction.c
• BZ - 1596846 - CVE-2018-10883 kernel: stack-out-of-bounds write in jbd2_journal_dirty_metadata function
• BZ - 1599161 - CVE-2018-13405 kernel: Missing check in fs/inode.c:inode_init_owner() does not clear SGID bit on non-directories for non-members
• BZ - 1601704 - CVE-2018-5390 kernel: TCP segments with random offsets allow a remote denial of service (SegmentSmack)
• BZ - 1609664 - CVE-2018-5391 kernel: IP fragments with random offsets allow a remote denial of service (FragmentSmack)
• BZ - 1610958 - CVE-2017-18344 kernel: out-of-bounds access in the show_timer function in kernel/time/posix-timers.c
• BZ - 1622004 - CVE-2018-14619 kernel: crash (possible privesc) in kernel crypto api.
• BZ - 1623067 - CVE-2018-9363 kernel: Buffer overflow in hidp_process_report
• BZ - 1629636 - CVE-2018-14641 kernel: a bug in ip_frag_reasm() can cause a crash in ip_do_fragment()

CVEs

• CVE-2017-13166
• CVE-2017-16648
• CVE-2017-17805
• CVE-2017-17806
• CVE-2017-18075
• CVE-2017-18208
• CVE-2017-18344
• CVE-2018-1065
• CVE-2018-1068
• CVE-2018-1092
• CVE-2018-1094
• CVE-2018-1095
• CVE-2018-1118
• CVE-2018-1120
• CVE-2018-3639
• CVE-2018-5344
• CVE-2018-5390
• CVE-2018-5391
• CVE-2018-5750
• CVE-2018-5803
• CVE-2018-5848
• CVE-2018-7566
• CVE-2018-7757
• CVE-2018-8781
• CVE-2018-9363
• CVE-2018-10322
• CVE-2018-10877
• CVE-2018-10878
• CVE-2018-10879
• CVE-2018-10880
• CVE-2018-10881
• CVE-2018-10882
• CVE-2018-10883
• CVE-2018-10940
• CVE-2018-11506
• CVE-2018-12232
• CVE-2018-13405
• CVE-2018-14619
• CVE-2018-14641
• CVE-2018-1000026
• CVE-2018-1000200
• CVE-2018-1000204

References

• https://access.redhat.com/security/updates/classification/#important
• https://access.redhat.com/articles/3553061
• https://access.redhat.com/security/vulnerabilities/ssbd
• https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html/7.6_release_notes/index
• https://access.redhat.com/articles/3658021