Bug 51846

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Description of problem:
If the unix_chkpwd program gets an empty password as input, it calls the
internal _unix_verify_password() function with NULL as the second argument
(the password.) This is supposed to be okay, but passing NULL to the
bigcrypt() function gives a segfault. A script is below.

Version-Release number of selected component (if applicable):


How reproducible:
Always

Steps to Reproduce:
This script will segfault unix_chkpwd:

#!/usr/bin/perl -w

pipe (FROM_PARENT, TO_CHILD);

if ($pid = fork) {
# I am the parent
close FROM_PARENT;
printf TO_CHILD "nullok%c%c", 0, 0;
print TO_CHILD "";
close TO_CHILD;
waitpid($pid, 0);
$childexit = $?;
print "child exited with $childexit\n";
} else {
die "cannot fork: $!" unless defined $pid;
# I am the child
open (STDIN, "<&FROM_PARENT") or die "$!";
exec '/sbin/unix_chkpwd' or die "cannot exec: $!";
}
exit;



Actual Results:  Get this in syslog:

Aug 15 14:18:13 thunderclap unix_chkpwd[10441]: caught signal 11.

Expected Results:  unix_chkpwd should return the failure code without
segfaulting.

Additional info:

I think passing "" instead of NULL to _unix_verify_password() will give the
desired results.