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/*-------------------------------------------------------------------------
*
* crypt.c
* Look into the password file and check the encrypted password with
* the one passed in from the frontend.
*
* Original coding by Todd A. Brandys
*
* Portions Copyright (c) 1996-2017, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* src/backend/libpq/crypt.c
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include <unistd.h>
#ifdef HAVE_CRYPT_H
#include <crypt.h>
#endif
#include "catalog/pg_authid.h"
#include "common/md5.h"
#include "libpq/crypt.h"
#include "miscadmin.h"
#include "utils/builtins.h"
#include "utils/syscache.h"
#include "utils/timestamp.h"
/*
* Fetch stored password for a user, for authentication.
*
* Returns STATUS_OK on success. On error, returns STATUS_ERROR, and stores
* a palloc'd string describing the reason, for the postmaster log, in
* *logdetail. The error reason should *not* be sent to the client, to avoid
* giving away user information!
*
* If the password is expired, it is still returned in *shadow_pass, but the
* return code is STATUS_ERROR. On other errors, *shadow_pass is set to
* NULL.
*/
int
get_role_password(const char *role, char **shadow_pass, char **logdetail)
{
int retval = STATUS_ERROR;
TimestampTz vuntil = 0;
HeapTuple roleTup;
Datum datum;
bool isnull;
*shadow_pass = NULL;
/* Get role info from pg_authid */
roleTup = SearchSysCache1(AUTHNAME, PointerGetDatum(role));
if (!HeapTupleIsValid(roleTup))
{
*logdetail = psprintf(_("Role \"%s\" does not exist."),
role);
return STATUS_ERROR; /* no such user */
}
datum = SysCacheGetAttr(AUTHNAME, roleTup,
Anum_pg_authid_rolpassword, &isnull);
if (isnull)
{
ReleaseSysCache(roleTup);
*logdetail = psprintf(_("User \"%s\" has no password assigned."),
role);
return STATUS_ERROR; /* user has no password */
}
*shadow_pass = TextDatumGetCString(datum);
datum = SysCacheGetAttr(AUTHNAME, roleTup,
Anum_pg_authid_rolvaliduntil, &isnull);
if (!isnull)
vuntil = DatumGetTimestampTz(datum);
ReleaseSysCache(roleTup);
if (**shadow_pass == '\0')
{
*logdetail = psprintf(_("User \"%s\" has an empty password."),
role);
pfree(*shadow_pass);
*shadow_pass = NULL;
return STATUS_ERROR; /* empty password */
}
/*
* Password OK, now check to be sure we are not past rolvaliduntil
*/
if (isnull)
retval = STATUS_OK;
else if (vuntil < GetCurrentTimestamp())
{
*logdetail = psprintf(_("User \"%s\" has an expired password."),
role);
retval = STATUS_ERROR;
}
else
retval = STATUS_OK;
return retval;
}
/*
* Check MD5 authentication response, and return STATUS_OK or STATUS_ERROR.
*
* 'shadow_pass' is the user's correct password or password hash, as stored
* in pg_authid.rolpassword.
* 'client_pass' is the response given by the remote user to the MD5 challenge.
* 'md5_salt' is the salt used in the MD5 authentication challenge.
*
* In the error case, optionally store a palloc'd string at *logdetail
* that will be sent to the postmaster log (but not the client).
*/
int
md5_crypt_verify(const char *role, const char *shadow_pass,
const char *client_pass,
const char *md5_salt, int md5_salt_len,
char **logdetail)
{
int retval;
char crypt_pwd[MD5_PASSWD_LEN + 1];
char crypt_pwd2[MD5_PASSWD_LEN + 1];
Assert(md5_salt_len > 0);
/*
* Compute the correct answer for the MD5 challenge.
*
* We do not bother setting logdetail for any pg_md5_encrypt failure
* below: the only possible error is out-of-memory, which is unlikely, and
* if it did happen adding a psprintf call would only make things worse.
*/
if (isMD5(shadow_pass))
{
/* stored password already encrypted, only do salt */
if (!pg_md5_encrypt(shadow_pass + strlen("md5"),
md5_salt, md5_salt_len,
crypt_pwd))
{
return STATUS_ERROR;
}
}
else
{
/* stored password is plain, double-encrypt */
if (!pg_md5_encrypt(shadow_pass,
role,
strlen(role),
crypt_pwd2))
{
return STATUS_ERROR;
}
if (!pg_md5_encrypt(crypt_pwd2 + strlen("md5"),
md5_salt, md5_salt_len,
crypt_pwd))
{
return STATUS_ERROR;
}
}
if (strcmp(client_pass, crypt_pwd) == 0)
retval = STATUS_OK;
else
{
*logdetail = psprintf(_("Password does not match for user \"%s\"."),
role);
retval = STATUS_ERROR;
}
return retval;
}
/*
* Check given password for given user, and return STATUS_OK or STATUS_ERROR.
*
* 'shadow_pass' is the user's correct password or password hash, as stored
* in pg_authid.rolpassword.
* 'client_pass' is the password given by the remote user.
*
* In the error case, optionally store a palloc'd string at *logdetail
* that will be sent to the postmaster log (but not the client).
*/
int
plain_crypt_verify(const char *role, const char *shadow_pass,
const char *client_pass,
char **logdetail)
{
int retval;
char crypt_client_pass[MD5_PASSWD_LEN + 1];
/*
* Client sent password in plaintext. If we have an MD5 hash stored, hash
* the password the client sent, and compare the hashes. Otherwise
* compare the plaintext passwords directly.
*/
if (isMD5(shadow_pass))
{
if (!pg_md5_encrypt(client_pass,
role,
strlen(role),
crypt_client_pass))
{
/*
* We do not bother setting logdetail for pg_md5_encrypt failure:
* the only possible error is out-of-memory, which is unlikely,
* and if it did happen adding a psprintf call would only make
* things worse.
*/
return STATUS_ERROR;
}
client_pass = crypt_client_pass;
}
if (strcmp(client_pass, shadow_pass) == 0)
retval = STATUS_OK;
else
{
*logdetail = psprintf(_("Password does not match for user \"%s\"."),
role);
retval = STATUS_ERROR;
}
return retval;
}
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