ALAS-2016-772

Related Vulnerabilities: CVE-2016-8645   CVE-2016-8655   CVE-2016-9083   CVE-2016-9084  

CVE-2016-8645 kernel: a BUG() statement can be hit in net/ipv4/tcp_input.cIt was discovered that the Linux kernel since 3.6-rc1 with net.ipv4.tcp_fastopen; set to 1 can hit BUG() statement in tcp_collapse() function after making a number of certain syscalls leading to a possible system crash. CVE-2016-8655 kernel: Race condition in packet_set_ring leads to use after freeA race condition issue leading to a use-after-free flaw was found in the way the raw packet sockets implementation in the Linux kernel networking subsystem handled synchronization while creating the TPACKET_V3 ring buffer. A local user able to open a raw packet socket (requires the CAP_NET_RAW capability) could use this flaw to elevate their privileges on the system. CVE-2016-9083 kernel: State machine confusion bug in vfio driver leading to memory corruptionA flaw was discovered in the Linux kernel's implementation of VFIO. An attacker issuing an ioctl can create a situation where memory is corrupted and modify memory outside of the expected area. This may overwrite kernel memory and subvert kernel execution. CVE-2016-9084 kernel: Integer overflow when using kzalloc in vfio driverThe use of a kzalloc with an integer multiplication allowed an integer overflow condition to be reached in vfio_pci_intrs.c. This combined with CVE-2016-9083 may allow an attacker to craft an attack and use unallocated memory, potentially crashing the machine.

ALAS-2016-772


Amazon Linux AMI Security Advisory: ALAS-2016-772
Advisory Release Date: 2016-12-06 23:44 Pacific
Advisory Updated Date: 2016-12-07 19:04 Pacific
Severity: Important

Issue Overview:

CVE-2016-8645 kernel: a BUG() statement can be hit in net/ipv4/tcp_input.c
It was discovered that the Linux kernel since 3.6-rc1 with net.ipv4.tcp_fastopen; set to 1 can hit BUG() statement in tcp_collapse() function after making a number of certain syscalls leading to a possible system crash.

CVE-2016-8655 kernel: Race condition in packet_set_ring leads to use after free
A race condition issue leading to a use-after-free flaw was found in the way the raw packet sockets implementation in the Linux kernel networking subsystem handled synchronization while creating the TPACKET_V3 ring buffer. A local user able to open a raw packet socket (requires the CAP_NET_RAW capability) could use this flaw to elevate their privileges on the system.

CVE-2016-9083 kernel: State machine confusion bug in vfio driver leading to memory corruption
A flaw was discovered in the Linux kernel's implementation of VFIO. An attacker issuing an ioctl can create a situation where memory is corrupted and modify memory outside of the expected area. This may overwrite kernel memory and subvert kernel execution.

CVE-2016-9084 kernel: Integer overflow when using kzalloc in vfio driver
The use of a kzalloc with an integer multiplication allowed an integer overflow condition to be reached in vfio_pci_intrs.c. This combined with CVE-2016-9083 may allow an attacker to craft an attack and use unallocated memory, potentially crashing the machine.


Affected Packages:

kernel


Issue Correction:
Run yum update kernel to update your system.

New Packages:
i686:
    kernel-debuginfo-common-i686-4.4.35-33.55.amzn1.i686
    perf-debuginfo-4.4.35-33.55.amzn1.i686
    kernel-tools-4.4.35-33.55.amzn1.i686
    perf-4.4.35-33.55.amzn1.i686
    kernel-4.4.35-33.55.amzn1.i686
    kernel-tools-debuginfo-4.4.35-33.55.amzn1.i686
    kernel-headers-4.4.35-33.55.amzn1.i686
    kernel-debuginfo-4.4.35-33.55.amzn1.i686
    kernel-tools-devel-4.4.35-33.55.amzn1.i686
    kernel-devel-4.4.35-33.55.amzn1.i686

noarch:
    kernel-doc-4.4.35-33.55.amzn1.noarch

src:
    kernel-4.4.35-33.55.amzn1.src

x86_64:
    kernel-tools-4.4.35-33.55.amzn1.x86_64
    perf-debuginfo-4.4.35-33.55.amzn1.x86_64
    kernel-headers-4.4.35-33.55.amzn1.x86_64
    kernel-tools-devel-4.4.35-33.55.amzn1.x86_64
    perf-4.4.35-33.55.amzn1.x86_64
    kernel-debuginfo-common-x86_64-4.4.35-33.55.amzn1.x86_64
    kernel-4.4.35-33.55.amzn1.x86_64
    kernel-devel-4.4.35-33.55.amzn1.x86_64
    kernel-debuginfo-4.4.35-33.55.amzn1.x86_64
    kernel-tools-debuginfo-4.4.35-33.55.amzn1.x86_64