Important kernel security update: Virtuozzo ReadyKernel patch 82.0 for all supported Virtuozzo 7.0 and Virtuozzo Infrastructure Platform 2.5 kernels

The cumulative Virtuozzo ReadyKernel patch was updated with security fixes. The patch applies to all supported kernels of Virtuozzo 7.0 and Virtuozzo Infrastructure Platform 2.5.
Vulnerability id: CVE-2019-11477
An integer overflow was found in the way the Linux kernel’s networking subsystem processed TCP Selective Acknowledgment (SACK) segments. While processing SACK segments, the Linux kernel’s socket buffer (SKB) data structure becomes fragmented. Each fragment is about TCP maximum segment size (MSS) bytes. To efficiently process SACK blocks, the Linux kernel merges multiple fragmented SKBs into one, potentially overflowing the variable holding the number of segments. A remote attacker could use this flaw to crash the Linux kernel by sending a crafted sequence of SACK segments on a TCP connection with small value of TCP MSS, resulting in a denial of service.

Vulnerability id: CVE-2019-11478
An excessive resource consumption issue was found in the way the Linux kernel’s networking subsystem processed TCP Selective Acknowledgment (SACK) segments. While processing SACK segments, the Linux kernel’s socket buffer (SKB) data structure becomes fragmented, which leads to increased resource utilization to traverse and process these fragments as further SACK segments are received on the same TCP connection. A remote attacker could use this flaw to cause a denial of service (DoS) by sending a crafted sequence of SACK segments on a TCP connection.