Add support for SHA256 and SHA512 encrypt methods. Apply RedHat's patch

shadow-4.0.18.1-sha256.patch. Thanks to Peter Vrabec. Hardly no changes
except re-indent and changes related to recent modifications (max_salt_len
in crypt_make_salt). Changes in lib/defines.h not applied (definition of
ENCRYPTMETHOD_SELECT). I will add a configure check or flag.

ChangeLog

@@ -1,3 +1,13 @@
+2007-11-19  Nicolas François  <nicolas.francois@centraliens.net>
+
+	* NEWS, libmisc/obscure.c, libmisc/salt.c, src/passwd.c,
+	lib/getdef.c, etc/login.defs: Add support for SHA256 and SHA512
+	encrypt methods. Apply RedHat's patch shadow-4.0.18.1-sha256.patch.
+	Thanks to Peter Vrabec. Hardly no changes except re-indent and
+	changes related to recent modifications (max_salt_len in
+	crypt_make_salt). Changes in lib/defines.h not applied (definition
+	of ENCRYPTMETHOD_SELECT). I will add a configure check or flag.
+
 2007-11-19  Nicolas François  <nicolas.francois@centraliens.net>
 
 	* man/de/Makefile.am: Add su.1 to the generated manpages.

NEWS

@@ -3,6 +3,8 @@ $Id$
 shadow-4.0.18.1 -> shadow-4.0.18.2					UNRELEASED
 
 *** general:
+- Add support for SHA256 and SHA512 encrypt methods (supported by new
+  libc).
 - useradd: Allow non numerical group identifier to be specified with
   useradd's -g option.
 - chgpasswd, chpasswd: Fix chpasswd and chgpasswd stack overflow.

etc/login.defs

@@ -278,6 +278,16 @@ CHFN_RESTRICT		rwh
 #
 #MD5_CRYPT_ENAB	no
 
+#
+# Only works if compiled with ENCRYPTMETHOD_SELECT defined:
+# If set to MD5 , MD5-based algorithm will be used for encrypting password
+# If set to SHA256, SHA256-based algorithm will be used for encrypting password
+# If set to SHA512, SHA512-based algorithm will be used for encrypting password
+# If set to DES, DES-based algorithm will be used for encrypting password (default)
+# Overrides the MD5_CRYPT_ENAB option
+#
+#ENCRYPT_METHOD DES
+
 #
 # List of groups to add to the user's supplementary group set
 # when logging in on the console (as determined by the CONSOLE

lib/getdef.c

@@ -84,6 +84,7 @@ static struct itemdef def_table[] = {
 	{"CHFN_AUTH", NULL},
 	{"CHSH_AUTH", NULL},
 	{"CRACKLIB_DICTPATH", NULL},
+	{"ENCRYPT_METHOD", NULL},
 	{"ENV_HZ", NULL},
 	{"ENVIRON_FILE", NULL},
 	{"ENV_TZ", NULL},

libmisc/obscure.c

@@ -210,6 +210,9 @@ static const char *password_check (const char *old, const char *new,
 	int maxlen, oldlen, newlen;
 	char *new1, *old1;
 	const char *msg;
+#ifdef ENCRYPTMETHOD_SELECT
+	char *result;
+#endif
 
 	oldlen = strlen (old);
 	newlen = strlen (new);
@@ -227,6 +230,9 @@ static const char *password_check (const char *old, const char *new,
 	if (msg)
 		return msg;
 
+#ifdef ENCRYPTMETHOD_SELECT
+	if ((result = getdef_str ("ENCRYPT_METHOD")) == NULL) {
+#endif
 	/* The traditional crypt() truncates passwords to 8 chars.  It is
 	   possible to circumvent the above checks by choosing an easy
 	   8-char password and adding some random characters to it...
@@ -234,8 +240,18 @@ static const char *password_check (const char *old, const char *new,
 	   truncated to the maximum length.  Idea from npasswd.  --marekm */
 
 		if (getdef_bool ("MD5_CRYPT_ENAB"))
-		return NULL;	/* unlimited password length */
+			return NULL;
 
+#ifdef ENCRYPTMETHOD_SELECT
+	} else {
+
+		if (!strncmp (result, "MD5"   , 3) ||
+		    !strncmp (result, "SHA256", 6) ||
+		    !strncmp (result, "SHA512", 6))
+			return NULL;
+
+	}
+#endif
 	maxlen = getdef_num ("PASS_MAX_LEN", 8);
 	if (oldlen <= maxlen && newlen <= maxlen)
 		return NULL;

libmisc/salt.c

@@ -58,20 +58,44 @@ char *l64a(long value)
  * (magic) and pw_encrypt() will execute the MD5-based FreeBSD-compatible
  * version of crypt() instead of the standard one.
  */
+
+#define MAGNUM(array,ch) (array)[0]= (array)[2] = '$',(array)[1]=(ch)
+
 char *crypt_make_salt (void)
 {
 	struct timeval tv;
 	static char result[40];
 	int max_salt_len = 8;
+	char *method;
 
-	result[0] = '\0';
 #ifndef USE_PAM
-	if (getdef_bool ("MD5_CRYPT_ENAB")) {
-		strcpy (result, "$1$");	/* magic for the new MD5 crypt() */
 		max_salt_len += 3;
-	}
+#ifdef ENCRYPTMETHOD_SELECT
+	if ((method = getdef_str ("ENCRYPT_METHOD")) == NULL) {
 #endif
-
+		if (getdef_bool ("MD5_CRYPT_ENAB")) {
+			MAGNUM(result,'1');
+			max_salt_len = 11;
+		} else
+			result[0] = '\0';
+#ifdef ENCRYPTMETHOD_SELECT
+	} else {
+		if (!strncmp (method, "MD5", 3)) {
+			MAGNUM(result, '1');
+			max_salt_len = 11;
+		} else if (!strncmp (method, "SHA256", 6)) {
+			MAGNUM(result, '5');
+			max_salt_len = 11; /* XXX: should not be fixed */
+		} else if (!strncmp (method, "SHA512", 6)) {
+			MAGNUM(result, '6');
+			max_salt_len = 11; /* XXX: should not be fixed */
+		} else if (!strncmp (method, "DES", 3))
+			result[0] = '\0';
+		else
+			result[0] = '\0';
+	}
+#endif				/* ENCRYPTMETHOD_SELECT */
+#endif				/* USE_PAM */
 	/*
 	 * Generate 8 chars of salt, the old crypt() will use only first 2.
 	 */

src/passwd.c

@@ -190,7 +190,10 @@ static int new_password (const struct passwd *pw)
 	char pass[200];		/* New password */
 	int i;			/* Counter for retries */
 	int warned;
-	int pass_max_len;
+	int pass_max_len = -1;
+#ifdef ENCRYPTMETHOD_SELECT
+	char *method;
+#endif
 
 #ifdef HAVE_LIBCRACK_HIST
 	int HistUpdate (const char *, const char *);
@@ -228,15 +231,34 @@ static int new_password (const struct passwd *pw)
 	 * for strength, unless it is the root user. This provides an escape
 	 * for initial login passwords.
 	 */
-	if (getdef_bool ("MD5_CRYPT_ENAB"))
+#ifdef ENCRYPTMETHOD_SELECT
-		pass_max_len = 127;
+	if ((method = getdef_str ("ENCRYPT_METHOD")) == NULL) {
+#endif
+		if (!getdef_bool ("MD5_CRYPT_ENAB"))
+			pass_max_len = getdef_num ("PASS_MAX_LEN", 8);
+#ifdef ENCRYPTMETHOD_SELECT
+	} else {
+		if (!strncmp (method, "MD5"   , 3) ||
+		    !strncmp (method, "SHA256", 6) ||
+		    !strncmp (method, "SHA512", 6))
+			pass_max_len = -1;
 		else
 			pass_max_len = getdef_num ("PASS_MAX_LEN", 8);
-
+	}
-	if (!qflg)
+#endif
-		printf (_("\
+	if (!qflg) {
-Enter the new password (minimum of %d, maximum of %d characters)\n\
+		if (pass_max_len == -1) {
-Please use a combination of upper and lower case letters and numbers.\n"), getdef_num ("PASS_MIN_LEN", 5), pass_max_len);
+			printf (_(
+"Enter the new password (minimum of %d characters)\n"
+"Please use a combination of upper and lower case letters and numbers.\n"),
+				getdef_num ("PASS_MIN_LEN", 5));
+		} else {
+			printf (_(
+"Enter the new password (minimum of %d, maximum of %d characters)\n"
+"Please use a combination of upper and lower case letters and numbers.\n"),
+				getdef_num ("PASS_MIN_LEN", 5), pass_max_len);
+		}
+	}
 
 	warned = 0;
 	for (i = getdef_num ("PASS_CHANGE_TRIES", 5); i > 0; i--) {