kernel: S_ISGD is not cleared when setting posix ACLs in tmpfs (CVE-2016-7097 incomplete fix)

A vulnerability was found in the Linux kernel in 'tmpfs' file system. When file permissions are modified via 'chmod' and the user is not in the owning group or capable of CAPFSETID, the setgid bit is cleared in inodechangeok. Setting a POSIX ACL via 'setxattr' sets the file permissions as well as...