149 lines
4.0 KiB
C
149 lines
4.0 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) 2009-2023, 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 "fmgr.h"
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#include "libpq/crypt.h"
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PG_MODULE_MAGIC;
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/* Saved hook value in case of unload */
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static check_password_hook_type prev_check_password_hook = NULL;
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/* passwords shorter than this will be rejected */
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#define MIN_PWD_LENGTH 8
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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 (prev_check_password_hook)
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prev_check_password_hook(username, shadow_pass,
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password_type, validuntil_time,
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validuntil_null);
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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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const char *logdetail = NULL;
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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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#ifdef USE_CRACKLIB
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const char *reason;
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#endif
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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 ((reason = 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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errdetail_log("cracklib diagnostic: %s", reason)));
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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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prev_check_password_hook = check_password_hook;
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check_password_hook = check_password;
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}
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