Index: lib/libcrypt/crypt.h
===================================================================
--- lib/libcrypt/crypt.h
+++ lib/libcrypt/crypt.h
@@ -34,12 +34,14 @@
 #define MD4_SIZE 16
 #define MD5_SIZE 16
 
+#define	CRYPT_SALT_MAX_LEN	16
+
 int crypt_des(const char *pw, const char *salt, char *buf);
 int crypt_md5(const char *pw, const char *salt, char *buf);
 int crypt_nthash(const char *pw, const char *salt, char *buf);
 int crypt_blowfish(const char *pw, const char *salt, char *buf);
-int crypt_sha256 (const char *pw, const char *salt, char *buf);
-int crypt_sha512 (const char *pw, const char *salt, char *buf);
+int crypt_sha256(const char *pw, const char *salt, char *buf);
+int crypt_sha512(const char *pw, const char *salt, char *buf);
 
 extern void _crypt_to64(char *s, u_long v, int n);
 extern void b64_from_24bit(uint8_t B2, uint8_t B1, uint8_t B0, int n, char **cp);
Index: lib/libcrypt/crypt.3
===================================================================
--- lib/libcrypt/crypt.3
+++ lib/libcrypt/crypt.3
@@ -221,8 +221,7 @@
 .\"
 .\" NOTICE: Also make sure to update this
 .\"
-DES
-if it is available, or MD5 if not.
+DES if it is available, or SHA-512 if not.
 .Pp
 How the salt is used will depend upon the algorithm for the hash.
 For
Index: lib/libcrypt/crypt.c
===================================================================
--- lib/libcrypt/crypt.c
+++ lib/libcrypt/crypt.c
@@ -34,10 +34,13 @@
 
 #include <libutil.h>
 #include <string.h>
+#include <stdio.h>
 #include <unistd.h>
 
 #include "crypt.h"
 
+#define	CRYPT_MAGIC_MAX_LEN	64
+
 /*
  * List of supported crypt(3) formats.
  *
@@ -62,13 +65,13 @@
 #ifdef HAS_DES
 	{ "des",	crypt_des,		"_"	},
 #endif
-
 	/* sentinel */
 	{ NULL,		NULL,			NULL	}
 };
 
-static const struct crypt_format *crypt_format =
-    &crypt_formats[(sizeof crypt_formats / sizeof *crypt_formats) - 2];
+static char crypt_default_magic[CRYPT_MAGIC_MAX_LEN] = "";
+static const struct crypt_format *crypt_default_format =
+	&crypt_formats[(sizeof crypt_formats / sizeof *crypt_formats) - 2];
 
 #define DES_SALT_ALPHABET \
 	"./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"
@@ -79,8 +82,7 @@
 const char *
 crypt_get_format(void)
 {
-
-	return (crypt_format->name);
+	return (crypt_default_format->name);
 }
 
 /*
@@ -92,9 +94,18 @@
 	const struct crypt_format *cf;
 
 	for (cf = crypt_formats; cf->name != NULL; ++cf) {
-		if (strcasecmp(cf->name, format) == 0) {
-			crypt_format = cf;
-			return (1);
+		if (format[0] == '$') {
+			if (strncmp(cf->magic, format, strlen(cf->magic)) == 0) {
+				strlcpy(crypt_default_magic, format, sizeof(crypt_default_magic));
+				crypt_default_format = cf;
+				return (1);
+			}
+		} else {
+			if (strcasecmp(cf->name, format) == 0) {
+				crypt_default_magic[0] = '\0';
+				crypt_default_format = cf;
+				return (1);
+			}
 		}
 	}
 	return (0);
@@ -113,6 +124,9 @@
 #ifdef HAS_DES
 	int len;
 #endif
+	char nsalt[CRYPT_MAGIC_MAX_LEN+CRYPT_SALT_MAX_LEN];
+
+	strlcpy(nsalt, salt, sizeof(nsalt));
 
 	for (cf = crypt_formats; cf->name != NULL; ++cf)
 		if (cf->magic != NULL && strstr(salt, cf->magic) == salt) {
@@ -126,9 +140,18 @@
 		goto match;
 	}
 #endif
-	func = crypt_format->func;
+	/*
+	 * New passwords come with an unprefixed salt, which we will prepend 
+	 * with the default magic (if available).  Otherwise we fallback to the 
+	 * default function.
+	 */
+	if (strcmp(crypt_default_magic, "") != 0) {
+		strlcpy(nsalt, crypt_default_magic, sizeof(nsalt));
+		strlcat(nsalt, salt, sizeof(nsalt));
+	}
+	func = crypt_default_format->func;
 match:
-	if (func(passwd, salt, data->__buf) != 0)
+	if (func(passwd, nsalt, data->__buf) != 0)
 		return (NULL);
 	return (data->__buf);
 }