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			138 lines
		
	
	
		
			3.6 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			138 lines
		
	
	
		
			3.6 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
/*-------------------------------------------------------------------------
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 *
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 * passwordcheck.c
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 *
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 *
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 * Copyright (c) 2009-2018, PostgreSQL Global Development Group
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 *
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 * Author: Laurenz Albe <laurenz.albe@wien.gv.at>
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 *
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 * IDENTIFICATION
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 *	  contrib/passwordcheck/passwordcheck.c
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 *
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 *-------------------------------------------------------------------------
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 */
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#include "postgres.h"
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#include <ctype.h>
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#ifdef USE_CRACKLIB
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#include <crack.h>
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#endif
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#include "commands/user.h"
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#include "libpq/crypt.h"
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#include "fmgr.h"
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PG_MODULE_MAGIC;
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/* passwords shorter than this will be rejected */
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#define MIN_PWD_LENGTH 8
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extern void _PG_init(void);
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/*
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 * check_password
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 *
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 * performs checks on an encrypted or unencrypted password
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 * ereport's if not acceptable
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 *
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 * username: name of role being created or changed
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 * password: new password (possibly already encrypted)
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 * password_type: PASSWORD_TYPE_* code, to indicate if the password is
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 *			in plaintext or encrypted form.
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 * validuntil_time: password expiration time, as a timestamptz Datum
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 * validuntil_null: true if password expiration time is NULL
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 *
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 * This sample implementation doesn't pay any attention to the password
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 * expiration time, but you might wish to insist that it be non-null and
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 * not too far in the future.
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 */
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static void
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check_password(const char *username,
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			   const char *shadow_pass,
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			   PasswordType password_type,
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			   Datum validuntil_time,
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			   bool validuntil_null)
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{
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	if (password_type != PASSWORD_TYPE_PLAINTEXT)
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	{
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		/*
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		 * Unfortunately we cannot perform exhaustive checks on encrypted
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		 * passwords - we are restricted to guessing. (Alternatively, we could
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		 * insist on the password being presented non-encrypted, but that has
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		 * its own security disadvantages.)
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		 *
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		 * We only check for username = password.
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		 */
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		char	   *logdetail;
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		if (plain_crypt_verify(username, shadow_pass, username, &logdetail) == STATUS_OK)
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			ereport(ERROR,
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					(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
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					 errmsg("password must not equal user name")));
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	}
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	else
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	{
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		/*
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		 * For unencrypted passwords we can perform better checks
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		 */
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		const char *password = shadow_pass;
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		int			pwdlen = strlen(password);
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		int			i;
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		bool		pwd_has_letter,
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					pwd_has_nonletter;
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		/* enforce minimum length */
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		if (pwdlen < MIN_PWD_LENGTH)
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			ereport(ERROR,
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					(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
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					 errmsg("password is too short")));
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		/* check if the password contains the username */
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		if (strstr(password, username))
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			ereport(ERROR,
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					(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
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					 errmsg("password must not contain user name")));
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		/* check if the password contains both letters and non-letters */
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		pwd_has_letter = false;
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		pwd_has_nonletter = false;
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		for (i = 0; i < pwdlen; i++)
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		{
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			/*
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			 * isalpha() does not work for multibyte encodings but let's
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			 * consider non-ASCII characters non-letters
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			 */
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			if (isalpha((unsigned char) password[i]))
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				pwd_has_letter = true;
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			else
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				pwd_has_nonletter = true;
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		}
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		if (!pwd_has_letter || !pwd_has_nonletter)
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			ereport(ERROR,
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					(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
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					 errmsg("password must contain both letters and nonletters")));
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#ifdef USE_CRACKLIB
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		/* call cracklib to check password */
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		if (FascistCheck(password, CRACKLIB_DICTPATH))
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			ereport(ERROR,
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					(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
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					 errmsg("password is easily cracked")));
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#endif
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	}
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	/* all checks passed, password is ok */
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}
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/*
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 * Module initialization function
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 */
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void
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_PG_init(void)
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{
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	/* activate password checks when the module is loaded */
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	check_password_hook = check_password;
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}
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