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auth.c
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/*-------------------------------------------------------------------------
*
* auth.c
* Routines to handle network authentication
*
* Portions Copyright (c) 1996-2024, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* src/backend/libpq/auth.c
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include <sys/param.h>
#include <sys/select.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
#include <pwd.h>
#include <unistd.h>
#include "commands/user.h"
#include "common/ip.h"
#include "common/md5.h"
#include "libpq/auth.h"
#include "libpq/crypt.h"
#include "libpq/libpq.h"
#include "libpq/pqformat.h"
#include "libpq/sasl.h"
#include "libpq/scram.h"
#include "miscadmin.h"
#include "port/pg_bswap.h"
#include "postmaster/postmaster.h"
#include "replication/walsender.h"
#include "storage/ipc.h"
#include "utils/memutils.h"
/*----------------------------------------------------------------
* Global authentication functions
*----------------------------------------------------------------
*/
static void auth_failed(Port *port, int status, const char *logdetail);
static char *recv_password_packet(Port *port);
static void set_authn_id(Port *port, const char *id);
/*----------------------------------------------------------------
* Password-based authentication methods (password, md5, and scram-sha-256)
*----------------------------------------------------------------
*/
static int CheckPasswordAuth(Port *port, const char **logdetail);
static int CheckPWChallengeAuth(Port *port, const char **logdetail);
static int CheckMD5Auth(Port *port, char *shadow_pass,
const char **logdetail);
/*----------------------------------------------------------------
* Ident authentication
*----------------------------------------------------------------
*/
/* Max size of username ident server can return (per RFC 1413) */
#define IDENT_USERNAME_MAX 512
/* Standard TCP port number for Ident service. Assigned by IANA */
#define IDENT_PORT 113
static int ident_inet(hbaPort *port);
/*----------------------------------------------------------------
* Peer authentication
*----------------------------------------------------------------
*/
static int auth_peer(hbaPort *port);
/*----------------------------------------------------------------
* PAM authentication
*----------------------------------------------------------------
*/
#ifdef USE_PAM
#ifdef HAVE_PAM_PAM_APPL_H
#include <pam/pam_appl.h>
#endif
#ifdef HAVE_SECURITY_PAM_APPL_H
#include <security/pam_appl.h>
#endif
#define PGSQL_PAM_SERVICE "postgresql" /* Service name passed to PAM */
static int CheckPAMAuth(Port *port, const char *user, const char *password);
static int pam_passwd_conv_proc(int num_msg, const struct pam_message **msg,
struct pam_response **resp, void *appdata_ptr);
static struct pam_conv pam_passw_conv = {
&pam_passwd_conv_proc,
NULL
};
static const char *pam_passwd = NULL; /* Workaround for Solaris 2.6
* brokenness */
static Port *pam_port_cludge; /* Workaround for passing "Port *port" into
* pam_passwd_conv_proc */
static bool pam_no_password; /* For detecting no-password-given */
#endif /* USE_PAM */
/*----------------------------------------------------------------
* BSD authentication
*----------------------------------------------------------------
*/
#ifdef USE_BSD_AUTH
#include <bsd_auth.h>
static int CheckBSDAuth(Port *port, char *user);
#endif /* USE_BSD_AUTH */
/*----------------------------------------------------------------
* LDAP authentication
*----------------------------------------------------------------
*/
#ifdef USE_LDAP
#ifndef WIN32
/* We use a deprecated function to keep the codepath the same as win32. */
#define LDAP_DEPRECATED 1
#include <ldap.h>
#else
#include <winldap.h>
#endif
static int CheckLDAPAuth(Port *port);
/* LDAP_OPT_DIAGNOSTIC_MESSAGE is the newer spelling */
#ifndef LDAP_OPT_DIAGNOSTIC_MESSAGE
#define LDAP_OPT_DIAGNOSTIC_MESSAGE LDAP_OPT_ERROR_STRING
#endif
/* Default LDAP password mutator hook, can be overridden by a shared library */
static char *dummy_ldap_password_mutator(char *input);
auth_password_hook_typ ldap_password_hook = dummy_ldap_password_mutator;
#endif /* USE_LDAP */
/*----------------------------------------------------------------
* Cert authentication
*----------------------------------------------------------------
*/
#ifdef USE_SSL
static int CheckCertAuth(Port *port);
#endif
/*----------------------------------------------------------------
* Kerberos and GSSAPI GUCs
*----------------------------------------------------------------
*/
char *pg_krb_server_keyfile;
bool pg_krb_caseins_users;
bool pg_gss_accept_delegation;
/*----------------------------------------------------------------
* GSSAPI Authentication
*----------------------------------------------------------------
*/
#ifdef ENABLE_GSS
#include "libpq/be-gssapi-common.h"
static int pg_GSS_checkauth(Port *port);
static int pg_GSS_recvauth(Port *port);
#endif /* ENABLE_GSS */
/*----------------------------------------------------------------
* SSPI Authentication
*----------------------------------------------------------------
*/
#ifdef ENABLE_SSPI
typedef SECURITY_STATUS
(WINAPI * QUERY_SECURITY_CONTEXT_TOKEN_FN) (PCtxtHandle, void **);
static int pg_SSPI_recvauth(Port *port);
static int pg_SSPI_make_upn(char *accountname,
size_t accountnamesize,
char *domainname,
size_t domainnamesize,
bool update_accountname);
#endif
/*----------------------------------------------------------------
* RADIUS Authentication
*----------------------------------------------------------------
*/
static int CheckRADIUSAuth(Port *port);
static int PerformRadiusTransaction(const char *server, const char *secret, const char *portstr, const char *identifier, const char *user_name, const char *passwd);
/*
* Maximum accepted size of GSS and SSPI authentication tokens.
* We also use this as a limit on ordinary password packet lengths.
*
* Kerberos tickets are usually quite small, but the TGTs issued by Windows
* domain controllers include an authorization field known as the Privilege
* Attribute Certificate (PAC), which contains the user's Windows permissions
* (group memberships etc.). The PAC is copied into all tickets obtained on
* the basis of this TGT (even those issued by Unix realms which the Windows
* realm trusts), and can be several kB in size. The maximum token size
* accepted by Windows systems is determined by the MaxAuthToken Windows
* registry setting. Microsoft recommends that it is not set higher than
* 65535 bytes, so that seems like a reasonable limit for us as well.
*/
#define PG_MAX_AUTH_TOKEN_LENGTH 65535
/*----------------------------------------------------------------
* Global authentication functions
*----------------------------------------------------------------
*/
/*
* This hook allows plugins to get control following client authentication,
* but before the user has been informed about the results. It could be used
* to record login events, insert a delay after failed authentication, etc.
*/
ClientAuthentication_hook_type ClientAuthentication_hook = NULL;
/*
* Tell the user the authentication failed, but not (much about) why.
*
* There is a tradeoff here between security concerns and making life
* unnecessarily difficult for legitimate users. We would not, for example,
* want to report the password we were expecting to receive...
* But it seems useful to report the username and authorization method
* in use, and these are items that must be presumed known to an attacker
* anyway.
* Note that many sorts of failure report additional information in the
* postmaster log, which we hope is only readable by good guys. In
* particular, if logdetail isn't NULL, we send that string to the log.
*/
static void
auth_failed(Port *port, int status, const char *logdetail)
{
const char *errstr;
char *cdetail;
int errcode_return = ERRCODE_INVALID_AUTHORIZATION_SPECIFICATION;
/*
* If we failed due to EOF from client, just quit; there's no point in
* trying to send a message to the client, and not much point in logging
* the failure in the postmaster log. (Logging the failure might be
* desirable, were it not for the fact that libpq closes the connection
* unceremoniously if challenged for a password when it hasn't got one to
* send. We'll get a useless log entry for every psql connection under
* password auth, even if it's perfectly successful, if we log STATUS_EOF
* events.)
*/
if (status == STATUS_EOF)
proc_exit(0);
switch (port->hba->auth_method)
{
case uaReject:
case uaImplicitReject:
errstr = gettext_noop("authentication failed for user \"%s\": host rejected");
break;
case uaTrust:
errstr = gettext_noop("\"trust\" authentication failed for user \"%s\"");
break;
case uaIdent:
errstr = gettext_noop("Ident authentication failed for user \"%s\"");
break;
case uaPeer:
errstr = gettext_noop("Peer authentication failed for user \"%s\"");
break;
case uaPassword:
case uaMD5:
case uaSCRAM:
errstr = gettext_noop("password authentication failed for user \"%s\"");
/* We use it to indicate if a .pgpass password failed. */
errcode_return = ERRCODE_INVALID_PASSWORD;
break;
case uaGSS:
errstr = gettext_noop("GSSAPI authentication failed for user \"%s\"");
break;
case uaSSPI:
errstr = gettext_noop("SSPI authentication failed for user \"%s\"");
break;
case uaPAM:
errstr = gettext_noop("PAM authentication failed for user \"%s\"");
break;
case uaBSD:
errstr = gettext_noop("BSD authentication failed for user \"%s\"");
break;
case uaLDAP:
errstr = gettext_noop("LDAP authentication failed for user \"%s\"");
break;
case uaCert:
errstr = gettext_noop("certificate authentication failed for user \"%s\"");
break;
case uaRADIUS:
errstr = gettext_noop("RADIUS authentication failed for user \"%s\"");
break;
default:
errstr = gettext_noop("authentication failed for user \"%s\": invalid authentication method");
break;
}
cdetail = psprintf(_("Connection matched file \"%s\" line %d: \"%s\""),
port->hba->sourcefile, port->hba->linenumber,
port->hba->rawline);
if (logdetail)
logdetail = psprintf("%s\n%s", logdetail, cdetail);
else
logdetail = cdetail;
ereport(FATAL,
(errcode(errcode_return),
errmsg(errstr, port->user_name),
logdetail ? errdetail_log("%s", logdetail) : 0));
/* doesn't return */
}
/*
* Sets the authenticated identity for the current user. The provided string
* will be stored into MyClientConnectionInfo, alongside the current HBA
* method in use. The ID will be logged if log_connections is enabled.
*
* Auth methods should call this routine exactly once, as soon as the user is
* successfully authenticated, even if they have reasons to know that
* authorization will fail later.
*
* The provided string will be copied into TopMemoryContext, to match the
* lifetime of MyClientConnectionInfo, so it is safe to pass a string that is
* managed by an external library.
*/
static void
set_authn_id(Port *port, const char *id)
{
Assert(id);
if (MyClientConnectionInfo.authn_id)
{
/*
* An existing authn_id should never be overwritten; that means two
* authentication providers are fighting (or one is fighting itself).
* Don't leak any authn details to the client, but don't let the
* connection continue, either.
*/
ereport(FATAL,
(errmsg("authentication identifier set more than once"),
errdetail_log("previous identifier: \"%s\"; new identifier: \"%s\"",
MyClientConnectionInfo.authn_id, id)));
}
MyClientConnectionInfo.authn_id = MemoryContextStrdup(TopMemoryContext, id);
MyClientConnectionInfo.auth_method = port->hba->auth_method;
if (Log_connections)
{
ereport(LOG,
errmsg("connection authenticated: identity=\"%s\" method=%s "
"(%s:%d)",
MyClientConnectionInfo.authn_id,
hba_authname(MyClientConnectionInfo.auth_method),
port->hba->sourcefile, port->hba->linenumber));
}
}
/*
* Client authentication starts here. If there is an error, this
* function does not return and the backend process is terminated.
*/
void
ClientAuthentication(Port *port)
{
int status = STATUS_ERROR;
const char *logdetail = NULL;
/*
* Get the authentication method to use for this frontend/database
* combination. Note: we do not parse the file at this point; this has
* already been done elsewhere. hba.c dropped an error message into the
* server logfile if parsing the hba config file failed.
*/
hba_getauthmethod(port);
CHECK_FOR_INTERRUPTS();
/*
* This is the first point where we have access to the hba record for the
* current connection, so perform any verifications based on the hba
* options field that should be done *before* the authentication here.
*/
if (port->hba->clientcert != clientCertOff)
{
/* If we haven't loaded a root certificate store, fail */
if (!secure_loaded_verify_locations())
ereport(FATAL,
(errcode(ERRCODE_CONFIG_FILE_ERROR),
errmsg("client certificates can only be checked if a root certificate store is available")));
/*
* If we loaded a root certificate store, and if a certificate is
* present on the client, then it has been verified against our root
* certificate store, and the connection would have been aborted
* already if it didn't verify ok.
*/
if (!port->peer_cert_valid)
ereport(FATAL,
(errcode(ERRCODE_INVALID_AUTHORIZATION_SPECIFICATION),
errmsg("connection requires a valid client certificate")));
}
/*
* Now proceed to do the actual authentication check
*/
switch (port->hba->auth_method)
{
case uaReject:
/*
* An explicit "reject" entry in pg_hba.conf. This report exposes
* the fact that there's an explicit reject entry, which is
* perhaps not so desirable from a security standpoint; but the
* message for an implicit reject could confuse the DBA a lot when
* the true situation is a match to an explicit reject. And we
* don't want to change the message for an implicit reject. As
* noted below, the additional information shown here doesn't
* expose anything not known to an attacker.
*/
{
char hostinfo[NI_MAXHOST];
const char *encryption_state;
pg_getnameinfo_all(&port->raddr.addr, port->raddr.salen,
hostinfo, sizeof(hostinfo),
NULL, 0,
NI_NUMERICHOST);
encryption_state =
#ifdef ENABLE_GSS
(port->gss && port->gss->enc) ? _("GSS encryption") :
#endif
#ifdef USE_SSL
port->ssl_in_use ? _("SSL encryption") :
#endif
_("no encryption");
if (am_walsender && !am_db_walsender)
ereport(FATAL,
(errcode(ERRCODE_INVALID_AUTHORIZATION_SPECIFICATION),
/* translator: last %s describes encryption state */
errmsg("pg_hba.conf rejects replication connection for host \"%s\", user \"%s\", %s",
hostinfo, port->user_name,
encryption_state)));
else
ereport(FATAL,
(errcode(ERRCODE_INVALID_AUTHORIZATION_SPECIFICATION),
/* translator: last %s describes encryption state */
errmsg("pg_hba.conf rejects connection for host \"%s\", user \"%s\", database \"%s\", %s",
hostinfo, port->user_name,
port->database_name,
encryption_state)));
break;
}
case uaImplicitReject:
/*
* No matching entry, so tell the user we fell through.
*
* NOTE: the extra info reported here is not a security breach,
* because all that info is known at the frontend and must be
* assumed known to bad guys. We're merely helping out the less
* clueful good guys.
*/
{
char hostinfo[NI_MAXHOST];
const char *encryption_state;
pg_getnameinfo_all(&port->raddr.addr, port->raddr.salen,
hostinfo, sizeof(hostinfo),
NULL, 0,
NI_NUMERICHOST);
encryption_state =
#ifdef ENABLE_GSS
(port->gss && port->gss->enc) ? _("GSS encryption") :
#endif
#ifdef USE_SSL
port->ssl_in_use ? _("SSL encryption") :
#endif
_("no encryption");
#define HOSTNAME_LOOKUP_DETAIL(port) \
(port->remote_hostname ? \
(port->remote_hostname_resolv == +1 ? \
errdetail_log("Client IP address resolved to \"%s\", forward lookup matches.", \
port->remote_hostname) : \
port->remote_hostname_resolv == 0 ? \
errdetail_log("Client IP address resolved to \"%s\", forward lookup not checked.", \
port->remote_hostname) : \
port->remote_hostname_resolv == -1 ? \
errdetail_log("Client IP address resolved to \"%s\", forward lookup does not match.", \
port->remote_hostname) : \
port->remote_hostname_resolv == -2 ? \
errdetail_log("Could not translate client host name \"%s\" to IP address: %s.", \
port->remote_hostname, \
gai_strerror(port->remote_hostname_errcode)) : \
0) \
: (port->remote_hostname_resolv == -2 ? \
errdetail_log("Could not resolve client IP address to a host name: %s.", \
gai_strerror(port->remote_hostname_errcode)) : \
0))
if (am_walsender && !am_db_walsender)
ereport(FATAL,
(errcode(ERRCODE_INVALID_AUTHORIZATION_SPECIFICATION),
/* translator: last %s describes encryption state */
errmsg("no pg_hba.conf entry for replication connection from host \"%s\", user \"%s\", %s",
hostinfo, port->user_name,
encryption_state),
HOSTNAME_LOOKUP_DETAIL(port)));
else
ereport(FATAL,
(errcode(ERRCODE_INVALID_AUTHORIZATION_SPECIFICATION),
/* translator: last %s describes encryption state */
errmsg("no pg_hba.conf entry for host \"%s\", user \"%s\", database \"%s\", %s",
hostinfo, port->user_name,
port->database_name,
encryption_state),
HOSTNAME_LOOKUP_DETAIL(port)));
break;
}
case uaGSS:
#ifdef ENABLE_GSS
/* We might or might not have the gss workspace already */
if (port->gss == NULL)
port->gss = (pg_gssinfo *)
MemoryContextAllocZero(TopMemoryContext,
sizeof(pg_gssinfo));
port->gss->auth = true;
/*
* If GSS state was set up while enabling encryption, we can just
* check the client's principal. Otherwise, ask for it.
*/
if (port->gss->enc)
status = pg_GSS_checkauth(port);
else
{
sendAuthRequest(port, AUTH_REQ_GSS, NULL, 0);
status = pg_GSS_recvauth(port);
}
#else
Assert(false);
#endif
break;
case uaSSPI:
#ifdef ENABLE_SSPI
if (port->gss == NULL)
port->gss = (pg_gssinfo *)
MemoryContextAllocZero(TopMemoryContext,
sizeof(pg_gssinfo));
sendAuthRequest(port, AUTH_REQ_SSPI, NULL, 0);
status = pg_SSPI_recvauth(port);
#else
Assert(false);
#endif
break;
case uaPeer:
status = auth_peer(port);
break;
case uaIdent:
status = ident_inet(port);
break;
case uaMD5:
case uaSCRAM:
status = CheckPWChallengeAuth(port, &logdetail);
break;
case uaPassword:
status = CheckPasswordAuth(port, &logdetail);
break;
case uaPAM:
#ifdef USE_PAM
status = CheckPAMAuth(port, port->user_name, "");
#else
Assert(false);
#endif /* USE_PAM */
break;
case uaBSD:
#ifdef USE_BSD_AUTH
status = CheckBSDAuth(port, port->user_name);
#else
Assert(false);
#endif /* USE_BSD_AUTH */
break;
case uaLDAP:
#ifdef USE_LDAP
status = CheckLDAPAuth(port);
#else
Assert(false);
#endif
break;
case uaRADIUS:
status = CheckRADIUSAuth(port);
break;
case uaCert:
/* uaCert will be treated as if clientcert=verify-full (uaTrust) */
case uaTrust:
status = STATUS_OK;
break;
}
if ((status == STATUS_OK && port->hba->clientcert == clientCertFull)
|| port->hba->auth_method == uaCert)
{
/*
* Make sure we only check the certificate if we use the cert method
* or verify-full option.
*/
#ifdef USE_SSL
status = CheckCertAuth(port);
#else
Assert(false);
#endif
}
if (Log_connections && status == STATUS_OK &&
!MyClientConnectionInfo.authn_id)
{
/*
* Normally, if log_connections is set, the call to set_authn_id()
* will log the connection. However, if that function is never
* called, perhaps because the trust method is in use, then we handle
* the logging here instead.
*/
ereport(LOG,
errmsg("connection authenticated: user=\"%s\" method=%s "
"(%s:%d)",
port->user_name, hba_authname(port->hba->auth_method),
port->hba->sourcefile, port->hba->linenumber));
}
if (ClientAuthentication_hook)
(*ClientAuthentication_hook) (port, status);
if (status == STATUS_OK)
sendAuthRequest(port, AUTH_REQ_OK, NULL, 0);
else
auth_failed(port, status, logdetail);
}
/*
* Send an authentication request packet to the frontend.
*/
void
sendAuthRequest(Port *port, AuthRequest areq, const char *extradata, int extralen)
{
StringInfoData buf;
CHECK_FOR_INTERRUPTS();
pq_beginmessage(&buf, PqMsg_AuthenticationRequest);
pq_sendint32(&buf, (int32) areq);
if (extralen > 0)
pq_sendbytes(&buf, extradata, extralen);
pq_endmessage(&buf);
/*
* Flush message so client will see it, except for AUTH_REQ_OK and
* AUTH_REQ_SASL_FIN, which need not be sent until we are ready for
* queries.
*/
if (areq != AUTH_REQ_OK && areq != AUTH_REQ_SASL_FIN)
pq_flush();
CHECK_FOR_INTERRUPTS();
}
/*
* Collect password response packet from frontend.
*
* Returns NULL if couldn't get password, else palloc'd string.
*/
static char *
recv_password_packet(Port *port)
{
StringInfoData buf;
int mtype;
pq_startmsgread();
/* Expect 'p' message type */
mtype = pq_getbyte();
if (mtype != PqMsg_PasswordMessage)
{
/*
* If the client just disconnects without offering a password, don't
* make a log entry. This is legal per protocol spec and in fact
* commonly done by psql, so complaining just clutters the log.
*/
if (mtype != EOF)
ereport(ERROR,
(errcode(ERRCODE_PROTOCOL_VIOLATION),
errmsg("expected password response, got message type %d",
mtype)));
return NULL; /* EOF or bad message type */
}
initStringInfo(&buf);
if (pq_getmessage(&buf, PG_MAX_AUTH_TOKEN_LENGTH)) /* receive password */
{
/* EOF - pq_getmessage already logged a suitable message */
pfree(buf.data);
return NULL;
}
/*
* Apply sanity check: password packet length should agree with length of
* contained string. Note it is safe to use strlen here because
* StringInfo is guaranteed to have an appended '\0'.
*/
if (strlen(buf.data) + 1 != buf.len)
ereport(ERROR,
(errcode(ERRCODE_PROTOCOL_VIOLATION),
errmsg("invalid password packet size")));
/*
* Don't allow an empty password. Libpq treats an empty password the same
* as no password at all, and won't even try to authenticate. But other
* clients might, so allowing it would be confusing.
*
* Note that this only catches an empty password sent by the client in
* plaintext. There's also a check in CREATE/ALTER USER that prevents an
* empty string from being stored as a user's password in the first place.
* We rely on that for MD5 and SCRAM authentication, but we still need
* this check here, to prevent an empty password from being used with
* authentication methods that check the password against an external
* system, like PAM, LDAP and RADIUS.
*/
if (buf.len == 1)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PASSWORD),
errmsg("empty password returned by client")));
/* Do not echo password to logs, for security. */
elog(DEBUG5, "received password packet");
/*
* Return the received string. Note we do not attempt to do any
* character-set conversion on it; since we don't yet know the client's
* encoding, there wouldn't be much point.
*/
return buf.data;
}
/*----------------------------------------------------------------
* Password-based authentication mechanisms
*----------------------------------------------------------------
*/
/*
* Plaintext password authentication.
*/
static int
CheckPasswordAuth(Port *port, const char **logdetail)
{
char *passwd;
int result;
char *shadow_pass;
sendAuthRequest(port, AUTH_REQ_PASSWORD, NULL, 0);
passwd = recv_password_packet(port);
if (passwd == NULL)
return STATUS_EOF; /* client wouldn't send password */
shadow_pass = get_role_password(port->user_name, logdetail);
if (shadow_pass)
{
result = plain_crypt_verify(port->user_name, shadow_pass, passwd,
logdetail);
}
else
result = STATUS_ERROR;
if (shadow_pass)
pfree(shadow_pass);
pfree(passwd);
if (result == STATUS_OK)
set_authn_id(port, port->user_name);
return result;
}
/*
* MD5 and SCRAM authentication.
*/
static int
CheckPWChallengeAuth(Port *port, const char **logdetail)
{
int auth_result;
char *shadow_pass;
PasswordType pwtype;
Assert(port->hba->auth_method == uaSCRAM ||
port->hba->auth_method == uaMD5);
/* First look up the user's password. */
shadow_pass = get_role_password(port->user_name, logdetail);
/*
* If the user does not exist, or has no password or it's expired, we
* still go through the motions of authentication, to avoid revealing to
* the client that the user didn't exist. If 'md5' is allowed, we choose
* whether to use 'md5' or 'scram-sha-256' authentication based on current
* password_encryption setting. The idea is that most genuine users
* probably have a password of that type, and if we pretend that this user
* had a password of that type, too, it "blends in" best.
*/
if (!shadow_pass)
pwtype = Password_encryption;
else
pwtype = get_password_type(shadow_pass);
/*
* If 'md5' authentication is allowed, decide whether to perform 'md5' or
* 'scram-sha-256' authentication based on the type of password the user
* has. If it's an MD5 hash, we must do MD5 authentication, and if it's a
* SCRAM secret, we must do SCRAM authentication.
*
* If MD5 authentication is not allowed, always use SCRAM. If the user
* had an MD5 password, CheckSASLAuth() with the SCRAM mechanism will
* fail.
*/
if (port->hba->auth_method == uaMD5 && pwtype == PASSWORD_TYPE_MD5)
auth_result = CheckMD5Auth(port, shadow_pass, logdetail);
else
auth_result = CheckSASLAuth(&pg_be_scram_mech, port, shadow_pass,
logdetail);
if (shadow_pass)
pfree(shadow_pass);
else
{
/*
* If get_role_password() returned error, authentication better not
* have succeeded.
*/
Assert(auth_result != STATUS_OK);
}
if (auth_result == STATUS_OK)
set_authn_id(port, port->user_name);
return auth_result;
}
static int
CheckMD5Auth(Port *port, char *shadow_pass, const char **logdetail)
{
char md5Salt[4]; /* Password salt */
char *passwd;
int result;
/* include the salt to use for computing the response */
if (!pg_strong_random(md5Salt, 4))
{
ereport(LOG,
(errmsg("could not generate random MD5 salt")));
return STATUS_ERROR;
}
sendAuthRequest(port, AUTH_REQ_MD5, md5Salt, 4);
passwd = recv_password_packet(port);
if (passwd == NULL)
return STATUS_EOF; /* client wouldn't send password */
if (shadow_pass)
result = md5_crypt_verify(port->user_name, shadow_pass, passwd,
md5Salt, 4, logdetail);
else
result = STATUS_ERROR;
pfree(passwd);
return result;
}
/*----------------------------------------------------------------
* GSSAPI authentication system
*----------------------------------------------------------------
*/
#ifdef ENABLE_GSS
static int
pg_GSS_recvauth(Port *port)
{
OM_uint32 maj_stat,
min_stat,
lmin_s,
gflags;
int mtype;
StringInfoData buf;
gss_buffer_desc gbuf;
gss_cred_id_t delegated_creds;
/*
* Use the configured keytab, if there is one. As we now require MIT
* Kerberos, we might consider using the credential store extensions in
* the future instead of the environment variable.
*/
if (pg_krb_server_keyfile != NULL && pg_krb_server_keyfile[0] != '\0')
{
if (setenv("KRB5_KTNAME", pg_krb_server_keyfile, 1) != 0)
{
/* The only likely failure cause is OOM, so use that errcode */
ereport(FATAL,
(errcode(ERRCODE_OUT_OF_MEMORY),
errmsg("could not set environment: %m")));
}
}
/*
* We accept any service principal that's present in our keytab. This
* increases interoperability between kerberos implementations that see
* for example case sensitivity differently, while not really opening up
* any vector of attack.
*/
port->gss->cred = GSS_C_NO_CREDENTIAL;
/*
* Initialize sequence with an empty context
*/
port->gss->ctx = GSS_C_NO_CONTEXT;
delegated_creds = GSS_C_NO_CREDENTIAL;
port->gss->delegated_creds = false;
/*
* Loop through GSSAPI message exchange. This exchange can consist of
* multiple messages sent in both directions. First message is always from
* the client. All messages from client to server are password packets
* (type 'p').
*/
do
{
pq_startmsgread();
CHECK_FOR_INTERRUPTS();
mtype = pq_getbyte();
if (mtype != PqMsg_GSSResponse)
{
/* Only log error if client didn't disconnect. */
if (mtype != EOF)
ereport(ERROR,
(errcode(ERRCODE_PROTOCOL_VIOLATION),
errmsg("expected GSS response, got message type %d",
mtype)));
return STATUS_ERROR;
}
/* Get the actual GSS token */
initStringInfo(&buf);
if (pq_getmessage(&buf, PG_MAX_AUTH_TOKEN_LENGTH))
{
/* EOF - pq_getmessage already logged error */
pfree(buf.data);
return STATUS_ERROR;
}
/* Map to GSSAPI style buffer */
gbuf.length = buf.len;
gbuf.value = buf.data;
elog(DEBUG4, "processing received GSS token of length %u",