etc/, lib/, man/, src/, tests/: Remove support for MD5

etc/login.defs

@@ -273,13 +273,6 @@ PASS_CHANGE_TRIES	5
 #
 PASS_ALWAYS_WARN	yes
 
-#
-# Number of significant characters in the password for crypt().
-# Default is 8, don't change unless your crypt() is better.
-# Only used for DES encryption algorithm.
-#
-#PASS_MAX_LEN		8
-
 #
 # Require password before chfn(1)/chsh(1) can make any changes.
 #
@@ -302,18 +295,15 @@ CHFN_RESTRICT		rwh
 
 #
 # 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 BCRYPT, BCRYPT-based algorithm will be used for encrypting password
 # If set to YESCRYPT, YESCRYPT-based algorithm will be used for encrypting password
-# If set to DES, DES-based algorithm will be used for encrypting password (default)
-# MD5 and DES should not be used for new hashes, see crypt(5) for recommendations.
 #
 # Note: if you use PAM, it is recommended to use a value consistent with
 # the PAM modules configuration.
 #
-#ENCRYPT_METHOD DES
+#ENCRYPT_METHOD SHA512
 
 #
 # Only works if ENCRYPT_METHOD is set to SHA256 or SHA512.

lib/chkhash.c

@@ -50,7 +50,7 @@ is_valid_hash(const char *hash)
 		return true;
 
 	// Minimum hash length
-	if (strlen(hash) < 13)
+	if (strlen(hash) < 48)
 		return false;
 
 	// Yescrypt: $y$ + algorithm parameters + $ + salt + $ + 43-char hash
@@ -69,14 +69,6 @@ is_valid_hash(const char *hash)
 	if (match_regex("^\\$5\\$(rounds=[1-9][0-9]{3,8}\\$)?[^$:\n]{1,16}\\$[./A-Za-z0-9]{43}$", hash))
 		return true;
 
-	// MD5: $1$ + salt + $ + 22-char hash
-	if (match_regex("^\\$1\\$[^$:\n]{1,8}\\$[./A-Za-z0-9]{22}$", hash))
-		return true;
-
-	// DES: exactly 13 characters from [A-Za-z0-9./]
-	if (match_regex("^[./A-Za-z0-9]{13}$", hash))
-		return true;
-
 	// Not a valid hash
 	return false;
 }

lib/getdef.c

@@ -63,7 +63,6 @@ struct itemdef {
 	{"OBSCURE_CHECKS_ENAB", NULL},		\
 	{"PASS_ALWAYS_WARN", NULL},		\
 	{"PASS_CHANGE_TRIES", NULL},		\
-	{"PASS_MAX_LEN", NULL},			\
 	{"PASS_MIN_LEN", NULL},			\
 	{"PORTTIME_CHECKS_ENAB", NULL},		\
 	{"QUOTAS_ENAB", NULL},			\

lib/obscure.c

@@ -12,6 +12,7 @@
 
 
 #include <ctype.h>
+#include <stddef.h>
 #include <stdio.h>
 #include <string.h>
 
@@ -26,10 +27,6 @@
 #include "string/strdup/strdup.h"
 
 
-#if WITH_LIBBSD == 0
-#include "freezero.h"
-#endif /* WITH_LIBBSD */
-
 /*
  * can't be a palindrome - like `R A D A R' or `M A D A M'
  */
@@ -59,7 +56,7 @@ static bool similar (/*@notnull@*/const char *old, /*@notnull@*/const char *new)
 
 	/*
 	 * XXX - sometimes this fails when changing from a simple password
-	 * to a really long one (MD5).  For now, I just return success if
+	 * to a really long one.  For now, I just return success if
 	 * the new password is long enough.  Please feel free to suggest
 	 * something better...  --marekm
 	 */
@@ -115,19 +112,8 @@ static /*@observer@*//*@null@*/const char *obscure_msg (
 	/*@notnull@*/const char *old,
 	/*@notnull@*/const char *new)
 {
-	int maxlen, minlen;
-	size_t oldlen, newlen;
-	char *new1, *old1;
-	const char *msg;
-
-	oldlen = strlen (old);
-	newlen = strlen (new);
-
-	obscure_get_range(&minlen, &maxlen);
-
-	if (newlen < (size_t) minlen) {
+	if (strlen(new) < pass_min_len())
 		return _("too short");
-	}
 
 	/*
 	 * Remaining checks are optional.
@@ -136,39 +122,7 @@ static /*@observer@*//*@null@*/const char *obscure_msg (
 		return NULL;
 	}
 
-	msg = password_check(old, new);
-	if (NULL != msg) {
-		return msg;
-	}
-
-	if (maxlen == -1) {
-		return NULL;
-	}
-
-	/* 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...
-	   Example: "password$%^&*123".  So check it again, this time
-	   truncated to the maximum length.  Idea from npasswd.  --marekm */
-
-	if (   (oldlen <= (size_t) maxlen)
-	    && (newlen <= (size_t) maxlen)) {
-		return NULL;
-	}
-
-	new1 = xstrdup (new);
-	old1 = xstrdup (old);
-	if (newlen > (size_t) maxlen)
-		stpcpy(&new1[maxlen], "");
-	if (oldlen > (size_t) maxlen)
-		stpcpy(&old1[maxlen], "");
-
-	msg = password_check(old1, new1);
-
-	freezero (new1, newlen);
-	freezero (old1, oldlen);
-
-	return msg;
+	return password_check(old, new);
 }
 
 /*
@@ -191,43 +145,12 @@ obscure(const char *old, const char *new)
 	return true;
 }
 
-/*
- * obscure_get_range - retrieve min and max password lengths
- *
- *  Returns minimum and maximum allowed lengths of a password
- *  to pass obscure checks.
- */
-void
-obscure_get_range(int *minlen, int *maxlen)
+size_t
+pass_min_len(void)
 {
-	int        val;
-	const char *method;
+	int  val;
 
 	/* Minimum length is 0, even if -1 is configured. */
 	val = getdef_num("PASS_MIN_LEN", 0);
-	*minlen = val == -1 ? 0 : val;
-
-	/* Maximum password length check is optional. */
-	*maxlen = -1;
-
-	if (!getdef_bool("OBSCURE_CHECKS_ENAB")) {
-		return;
-	}
-
-	method = getdef_str ("ENCRYPT_METHOD");
-	if (NULL != method) {
-		if (   streq(method, "MD5")
-		    || streq(method, "SHA256")
-		    || streq(method, "SHA512")
-#ifdef USE_BCRYPT
-		    || streq(method, "BCRYPT")
-#endif
-#ifdef USE_YESCRYPT
-		    || streq(method, "YESCRYPT")
-#endif
-		    ) {
-			return;
-		}
-	}
-	*maxlen = getdef_num ("PASS_MAX_LEN", 8);
+	return val == -1 ? 0 : val;
 }

lib/prototypes.h

@@ -301,7 +301,7 @@ extern int do_pam_passwd_non_interactive (const char *pam_service,
 
 /* obscure.c */
 extern bool obscure (const char *, const char *);
-extern void obscure_get_range(int *, int *);
+extern size_t pass_min_len(void);
 
 /* pam_pass.c */
 #ifdef USE_PAM

lib/salt.c

@@ -77,9 +77,6 @@
 #define Y_COST_MAX 11
 #endif
 
-/* Fixed salt len for md5crypt. */
-#define MD5_CRYPT_SALT_SIZE 8
-
 /* Generate salt of size salt_size. */
 #define MAX_SALT_SIZE 44
 #define MIN_SALT_SIZE 8
@@ -355,12 +352,13 @@ static /*@observer@*/const char *gensalt (size_t salt_size)
 
 	bzero(result, GENSALT_SETTING_SIZE);
 
-	method = meth ?: getdef_str("ENCRYPT_METHOD") ?: "DES";
+	method = meth ?: getdef_str("ENCRYPT_METHOD") ?: "SHA512";
 
-	if (streq(method, "MD5")) {
-		MAGNUM(result, '1');
-		salt_len = MD5_CRYPT_SALT_SIZE;
-		rounds = 0;
+	if (streq(method, "SHA256")) {
+		MAGNUM(result, '5');
+		salt_len = SHA_CRYPT_SALT_SIZE;
+		rounds = SHA_get_salt_rounds (arg);
+		SHA_salt_rounds_to_buf (result, rounds);
 #ifdef USE_BCRYPT
 	} else if (streq(method, "BCRYPT")) {
 		BCRYPTMAGNUM(result);
@@ -375,39 +373,21 @@ static /*@observer@*/const char *gensalt (size_t salt_size)
 		rounds = YESCRYPT_get_salt_cost (arg);
 		YESCRYPT_salt_cost_to_buf (result, rounds);
 #endif /* USE_YESCRYPT */
-	} else if (streq(method, "SHA256")) {
-		MAGNUM(result, '5');
-		salt_len = SHA_CRYPT_SALT_SIZE;
-		rounds = SHA_get_salt_rounds (arg);
-		SHA_salt_rounds_to_buf (result, rounds);
 	} else if (streq(method, "SHA512")) {
+sha512:
 		MAGNUM(result, '6');
 		salt_len = SHA_CRYPT_SALT_SIZE;
 		rounds = SHA_get_salt_rounds (arg);
 		SHA_salt_rounds_to_buf (result, rounds);
-	} else if (!streq(method, "DES")) {
+	} else {
 		fprintf (log_get_logfd(),
 			 _("Invalid ENCRYPT_METHOD value: '%s'.\n"
-			   "Defaulting to DES.\n"),
+			   "Defaulting to SHA512.\n"),
 			 method);
-		salt_len = MAX_SALT_SIZE;
-		rounds = 0;
-		bzero(result, GENSALT_SETTING_SIZE);
+		goto sha512;
 	}
 
 #if USE_XCRYPT_GENSALT
-	/*
-	 * Prepare DES setting for crypt_gensalt(), if result
-	 * has not been filled with anything previously.
-	 */
-	if (streq(result, "")) {
-		/* Avoid -Wunused-but-set-variable. */
-		salt_len = GENSALT_SETTING_SIZE - 1;
-		rounds = 0;
-		memset(result, '.', salt_len);
-		stpcpy(&result[salt_len], "");
-	}
-
 	char *retval = crypt_gensalt (result, rounds, NULL, 0);
 
 	/* Should not happen, but... */

lib/valid.c

@@ -23,7 +23,7 @@
 /*
  * valid - compare encrypted passwords
  *
- *	Valid() compares the DES encrypted password from the password file
+ *	Valid() compares the hashed password from the password file
  *	against the password which the user has entered after it has been
  *	encrypted using the same salt as the original.  Entries which do
  *	not have a password file entry have a NULL pw_name field and this

man/Makefile.am

@@ -161,7 +161,7 @@ login_defs_v = \
 	PASS_ALWAYS_WARN.xml \
 	PASS_CHANGE_TRIES.xml \
 	PASS_MAX_DAYS.xml \
-	PASS_MAX_LEN.xml \
+	PASS_MIN_LEN.xml \
 	PASS_MIN_DAYS.xml \
 	PASS_WARN_AGE.xml \
 	PORTTIME_CHECKS_ENAB.xml \

man/chgpasswd.8.xml

@@ -92,8 +92,6 @@
 	  <para>
 	    The available methods are <phrase condition="bcrypt">
 	    <replaceable>BCRYPT</replaceable>,</phrase>
-	    <replaceable>DES</replaceable>,
-	    <replaceable>MD5</replaceable>,
 	    <replaceable>SHA256</replaceable>,
 	    <replaceable>SHA512</replaceable>,
 	    <phrase condition="yescrypt">

man/chpasswd.8.xml

@@ -118,8 +118,6 @@
 	  <para>
 	    The available methods are <phrase condition="bcrypt">
 	    <replaceable>BCRYPT</replaceable>,</phrase>
-	    <replaceable>DES</replaceable>,
-	    <replaceable>MD5</replaceable>,
 	    <replaceable>SHA256</replaceable>,
 	    <replaceable>SHA512</replaceable>,
 	    <phrase condition="yescrypt">

man/login.defs.d/ENCRYPT_METHOD.xml

@@ -12,13 +12,11 @@
     <para>
       It can take one of these values: <phrase condition="bcrypt">
       <replaceable>BCRYPT</replaceable>,</phrase>
-      <replaceable>DES</replaceable> (default),
-      <replaceable>MD5</replaceable>,
       <replaceable>SHA256</replaceable>,
       <replaceable>SHA512</replaceable>,
       <phrase condition="yescrypt">
       <replaceable>YESCRYPT</replaceable></phrase>.
-      MD5 and DES should not be used for new hashes, see
+      See
       <refentrytitle>crypt</refentrytitle><manvolnum>5</manvolnum>
       for recommendations.
     </para>

man/login.defs.d/PASS_MIN_LEN.xml

@@ -0,0 +1,12 @@
+<!--
+   SPDX-FileCopyrightText: 2025, Alejandro Colomar <alx@kernel.org>
+   SPDX-License-Identifier: BSD-3-Clause
+-->
+<varlistentry condition="no_pam">
+  <term><option>PASS_MIN_LEN</option> (number)</term>
+  <listitem>
+    <para>
+      Minimum allowed length of a password.
+    </para>
+  </listitem>
+</varlistentry>

man/newusers.8.xml

@@ -271,7 +271,7 @@
 	<listitem>
 	  <para>Use the specified method to encrypt the passwords.</para>
 	  <para>
-	    The available methods are DES, MD5, NONE, and SHA256 or SHA512
+	    The available methods are NONE, and SHA256 or SHA512
 	    if your libc support these methods.
 	  </para>
 	</listitem>