CVE-2017-7618 2017-05-12 09:42:13 Amazon Linux Security Advisory for kernel: ALAS-2017-828

Infinite recursion in ahash.c by triggering EBUSY on a full queue:
A vulnerability was found in crypto/ahash.c in the Linux kernel which allows attackers to cause a denial of service (API operation calling its own callback, and infinite recursion) by triggering EBUSY on a full queue.(CVE-2017-7618 )

Time subsystem allows local users to discover real PID values:
The time subsystem in the Linux kernel, when CONFIG_TIMER_STATS is enabled, allows local users to discover real PID values (as distinguished from PID values inside a PID namespace) by reading the /proc/timer_list file, related to the print_timer function in kernel/time/timer_list.c and the __timer_stats_timer_set_start_info function in kernel/time/timer.c.(CVE-2017-5967 )

Stack-based buffer overflow in sg_ioctl function:
The sg_ioctl function in drivers/scsi/sg.c in the Linux kernel allows local users to cause a denial of service (stack-based buffer overflow) or possibly have unspecified other impacts via a large command size in an SG_NEXT_CMD_LEN ioctl call, leading to out-of-bounds write access in the sg_write function. (CVE-2017-7187 )

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

Race condition in Link Layer Control:
A race condition leading to a NULL pointer dereference was found in the Linux kernel's Link Layer Control implementation. A local attacker with access to ping sockets could use this flaw to crash the system. (CVE-2017-2671 )

Overflow in check for priv area size:
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, although we believe it is unlikely. (CVE-2017-7308 )

QID Detection Logic:
This authenticated QID checks if the following file versions are lesser than 4.9.27-14.31.amzn1: kernel-tools-debuginfo, kernel-headers, kernel-tools, perf-debuginfo, perf, kernel-tools-devel, kernel-debuginfo-common-x86_64, kernel-debuginfo, kernel, kernel-devel, kernel-doc, kernel-debuginfo-common-i686.

Allows unauthorized disclosure of information; allows unauthorized modification; allows disruption of service.

Please refer to Amazon advisory ALAS-2017-828 for affected packages and patching details, or update with your package manager.

Patch:
Following are links for downloading patches to fix the vulnerabilities:

ALAS-2017-828: Amazon Linux (kernel (4.9.27-14.31.amzn1) on noarch)

ALAS-2017-828: Amazon Linux (kernel (4.9.27-14.31.amzn1) on x86_64)

ALAS-2017-828: Amazon Linux (kernel (4.9.27-14.31.amzn1) on src)

ALAS-2017-828: Amazon Linux (kernel (4.9.27-14.31.amzn1) on i686)