ensured that crypt("", "") would return "", which supported matcing
empty encrypted passwords with no additional code. Some modern
versions of crypt() (such as glibc) return NULL on error so we need
an explicit test to match an empty plaintext password and an empty
encrypted password.
A new constant, SUDO_CONV_REPL_MAX, is defined by the plugin
API as the max conversation reply length. This constant can be
used as a max value for memset_s() when clearing passwords
filled in by the conversation function.
MAXHOSTNAMELEN and the MIN/MAX macros. We now use PATH_MAX and
HOST_NAME_MAX throughout without falling back on MAXPATHLEN or
MAXHOSTNAMELEN and define our own MIN/MAX macros as needed.
Set adminstrative domain for the process when looking up user's
password or group info and when preparing for execve().
Include strings.h even if string.h exists since they may define
different things. Fixes warnings on AIX and others.
