Samba is an open-source implementation of the Server Message Block protocol and the related Common Internet File System protocol, which allow PC-compatible machines to share files, printers, and various information. Security Fix: * It was found that samba did not enforce "SMB signing" when certain configuration options were enabled. A remote attacker could launch a man-in-the-middle attack and retrieve information in plain-text. * A flaw was found in the way samba client used encryption with the max protocol set as SMB3. The connection could lose the requirement for signing and encrypting to any DFS redirects, allowing an attacker to read or alter the contents of the connection via a man-in-the-middle attack. * An information leak flaw was found in the way SMB1 protocol was implemented by Samba. A malicious client could use this flaw to dump server memory contents to a file on the samba share or to a shared printer, though the exact area of server memory cannot be controlled by the attacker. Red Hat would like to thank the Samba project for reporting CVE-2017-12150 and CVE-2017-12151 and Yihan Lian and Zhibin Hu , Stefan Metzmacher , and Jeremy Allison for reporting CVE-2017-12163. Upstream acknowledges Stefan Metzmacher as the original reporter of CVE-2017-12150 and CVE-2017-12151.