https://github.com/OpenSMTPD/OpenSMTPD/pull/835

avoid null pointer deref if crypt(3) fails and returns null

include "includes.h" so HAVE_CRYPT_H is defined and crypt.h gets included

--- openbsd-compat/crypt_checkpass.c
+++ openbsd-compat/crypt_checkpass.c
@@ -1,5 +1,6 @@
 /* OPENBSD ORIGINAL: lib/libc/crypt/cryptutil.c */

+#include "includes.h"
 #include <errno.h>
 #ifdef HAVE_CRYPT_H
 #include <crypt.h>
@@ -10,6 +11,8 @@
 int
 crypt_checkpass(const char *pass, const char *goodhash)
 {
+       char *c;
+
        if (goodhash == NULL)
                goto fail;

@@ -17,7 +20,11 @@ crypt_checkpass(const char *pass, const char *goodhash)
        if (strlen(goodhash) == 0 && strlen(pass) == 0)
                return 0;

-       if (strcmp(crypt(pass, goodhash), goodhash) == 0)
+       c = crypt(pass, goodhash);
+       if (c == NULL)
+               goto fail;
+
+       if (strcmp(c, goodhash) == 0)
                return 0;

 fail: