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eb61136dc7
Storing passwords in plaintext hasn't been a good idea for a very long time, if ever. Now seems like a good time to finally forbid it, since we're messing with this in PostgreSQL 10 anyway. Remove the CREATE/ALTER USER UNENCRYPTED PASSSWORD 'foo' syntax, since storing passwords unencrypted is no longer supported. ENCRYPTED PASSWORD 'foo' is still accepted, but ENCRYPTED is now just a noise-word, it does the same as just PASSWORD 'foo'. Likewise, remove the --unencrypted option from createuser, but accept --encrypted as a no-op for backward compatibility. AFAICS, --encrypted was a no-op even before this patch, because createuser encrypted the password before sending it to the server even if --encrypted was not specified. It added the ENCRYPTED keyword to the SQL command, but since the password was already in encrypted form, it didn't make any difference. The documentation was not clear on whether that was intended or not, but it's moot now. Also, while password_encryption='on' is still accepted as an alias for 'md5', it is now marked as hidden, so that it is not listed as an accepted value in error hints, for example. That's not directly related to removing 'plain', but it seems better this way. Reviewed by Michael Paquier Discussion: https://www.postgresql.org/message-id/16e9b768-fd78-0b12-cfc1-7b6b7f238fde@iki.fi
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) 2009-2017, 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 contain 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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