Reason: In routine make_passwd() in yppasswdd_mkpw.c, fgets() is used
to read master.passwd line-by-line. The lines are then parsed using
pw_scan(), without removing the trailing \n from the line. pw_scan()
fills in the shell name into pw.pw_shell, including the trailing \n.
Subsequently, rpc.yppasswdd calls pw_copy(), which copies master.passwd
to ptmp, updating the entry for pw.pw_name. pw_copy() terminates the
updated entry with an additonal \n, so that there is now an empty line
in ptmp.
Finally, rpc.yppasswdd calls pw_mkdb(3), which exec's /usr/sbin/pwd_mkdb
to install ptmp to master.passwd (and to create the pwd.db and spwd.db
data bases). pwd_mkdb chokes on the empty ptmp line.
Fix: remove the trailing \n from the buffer fgets() returns. As a side
effect, this gets us some additional error checking.
Reviewed by <tron>.
0269a1249b