/*-------------------------------------------------------------------------
*
* fe-auth.c
* The front-end (client) authorization routines
*
* Portions Copyright (c) 1996-2015, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* src/interfaces/libpq/fe-auth.c
*
*-------------------------------------------------------------------------
*/
/*
* INTERFACE ROUTINES
* frontend (client) routines:
* pg_fe_sendauth send authentication information
* pg_fe_getauthname get user's name according to the client side
* of the authentication system
*/
#include "postgres_fe.h"
#ifdef WIN32
#include "win32.h"
#else
#include <unistd.h>
#include <fcntl.h>
#include <sys/param.h> /* for MAXHOSTNAMELEN on most */
#include <sys/socket.h>
#ifdef HAVE_SYS_UCRED_H
#include <sys/ucred.h>
#endif
#ifndef MAXHOSTNAMELEN
#include <netdb.h> /* for MAXHOSTNAMELEN on some */
#endif
#include <pwd.h>
#endif
#include "libpq-fe.h"
#include "fe-auth.h"
#include "libpq/md5.h"
#ifdef ENABLE_GSS
/*
* GSSAPI authentication system.
*/
#if defined(WIN32) && !defined(WIN32_ONLY_COMPILER)
/*
* MIT Kerberos GSSAPI DLL doesn't properly export the symbols for MingW
* that contain the OIDs required. Redefine here, values copied
* from src/athena/auth/krb5/src/lib/gssapi/generic/gssapi_generic.c
*/
static const gss_OID_desc GSS_C_NT_HOSTBASED_SERVICE_desc =
{10, (void *) "\x2a\x86\x48\x86\xf7\x12\x01\x02\x01\x04"};
static GSS_DLLIMP gss_OID GSS_C_NT_HOSTBASED_SERVICE = &GSS_C_NT_HOSTBASED_SERVICE_desc;
#endif
/*
* Fetch all errors of a specific type and append to "str".
*/
static void
pg_GSS_error_int(PQExpBuffer str, const char *mprefix,
OM_uint32 stat, int type)
{
OM_uint32 lmin_s;
gss_buffer_desc lmsg;
OM_uint32 msg_ctx = 0;
do
{
gss_display_status(&lmin_s, stat, type,
GSS_C_NO_OID, &msg_ctx, &lmsg);
appendPQExpBuffer(str, "%s: %s\n", mprefix, (char *) lmsg.value);
gss_release_buffer(&lmin_s, &lmsg);
} while (msg_ctx);
}
/*
* GSSAPI errors contain two parts; put both into conn->errorMessage.
*/
static void
pg_GSS_error(const char *mprefix, PGconn *conn,
OM_uint32 maj_stat, OM_uint32 min_stat)
{
resetPQExpBuffer(&conn->errorMessage);
/* Fetch major error codes */
pg_GSS_error_int(&conn->errorMessage, mprefix, maj_stat, GSS_C_GSS_CODE);
/* Add the minor codes as well */
pg_GSS_error_int(&conn->errorMessage, mprefix, min_stat, GSS_C_MECH_CODE);
}
/*
* Continue GSS authentication with next token as needed.
*/
static int
pg_GSS_continue(PGconn *conn)
{
OM_uint32 maj_stat,
min_stat,
lmin_s;
maj_stat = gss_init_sec_context(&min_stat,
GSS_C_NO_CREDENTIAL,
&conn->gctx,
conn->gtarg_nam,
GSS_C_NO_OID,
GSS_C_MUTUAL_FLAG,
0,
GSS_C_NO_CHANNEL_BINDINGS,
(conn->gctx == GSS_C_NO_CONTEXT) ? GSS_C_NO_BUFFER : &conn->ginbuf,
NULL,
&conn->goutbuf,
NULL,
NULL);
if (conn->gctx != GSS_C_NO_CONTEXT)
{
free(conn->ginbuf.value);
conn->ginbuf.value = NULL;
conn->ginbuf.length = 0;
}
if (conn->goutbuf.length != 0)
{
/*
* GSS generated data to send to the server. We don't care if it's the
* first or subsequent packet, just send the same kind of password
* packet.
*/
if (pqPacketSend(conn, 'p',
conn->goutbuf.value, conn->goutbuf.length)
!= STATUS_OK)
{
gss_release_buffer(&lmin_s, &conn->goutbuf);
return STATUS_ERROR;
}
}
gss_release_buffer(&lmin_s, &conn->goutbuf);
if (maj_stat != GSS_S_COMPLETE && maj_stat != GSS_S_CONTINUE_NEEDED)
{
pg_GSS_error(libpq_gettext("GSSAPI continuation error"),
conn,
maj_stat, min_stat);
gss_release_name(&lmin_s, &conn->gtarg_nam);
if (conn->gctx)
gss_delete_sec_context(&lmin_s, &conn->gctx, GSS_C_NO_BUFFER);
return STATUS_ERROR;
}
if (maj_stat == GSS_S_COMPLETE)
gss_release_name(&lmin_s, &conn->gtarg_nam);
return STATUS_OK;
}
/*
* Send initial GSS authentication token
*/
static int
pg_GSS_startup(PGconn *conn)
{
OM_uint32 maj_stat,
min_stat;
int maxlen;
gss_buffer_desc temp_gbuf;
if (!(conn->pghost && conn->pghost[0] != '\0'))
{
printfPQExpBuffer(&conn->errorMessage,
libpq_gettext("host name must be specified\n"));
return STATUS_ERROR;
}
if (conn->gctx)
{
printfPQExpBuffer(&conn->errorMessage,
libpq_gettext("duplicate GSS authentication request\n"));
return STATUS_ERROR;
}
/*
* Import service principal name so the proper ticket can be acquired by
* the GSSAPI system.
*/
maxlen = NI_MAXHOST + strlen(conn->krbsrvname) + 2;
temp_gbuf.value = (char *) malloc(maxlen);
if (!temp_gbuf.value)
{
printfPQExpBuffer(&conn->errorMessage,
libpq_gettext("out of memory\n"));
return STATUS_ERROR;
}
snprintf(temp_gbuf.value, maxlen, "%s@%s",
conn->krbsrvname, conn->pghost);
temp_gbuf.length = strlen(temp_gbuf.value);
maj_stat = gss_import_name(&min_stat, &temp_gbuf,
GSS_C_NT_HOSTBASED_SERVICE, &conn->gtarg_nam);
free(temp_gbuf.value);
if (maj_stat != GSS_S_COMPLETE)
{
pg_GSS_error(libpq_gettext("GSSAPI name import error"),
conn,
maj_stat, min_stat);
return STATUS_ERROR;
}
/*
* Initial packet is the same as a continuation packet with no initial
* context.
*/
conn->gctx = GSS_C_NO_CONTEXT;
return pg_GSS_continue(conn);
}
#endif /* ENABLE_GSS */
#ifdef ENABLE_SSPI
/*
* SSPI authentication system (Windows only)
*/
static void
pg_SSPI_error(PGconn *conn, const char *mprefix, SECURITY_STATUS r)
{
char sysmsg[256];
if (FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM, NULL, r, 0,
sysmsg, sizeof(sysmsg), NULL) == 0)
printfPQExpBuffer(&conn->errorMessage, "%s: SSPI error %x\n",
mprefix, (unsigned int) r);
else
printfPQExpBuffer(&conn->errorMessage, "%s: %s (%x)\n",
mprefix, sysmsg, (unsigned int) r);
}
/*
* Continue SSPI authentication with next token as needed.
*/
static int
pg_SSPI_continue(PGconn *conn)
{
SECURITY_STATUS r;
CtxtHandle newContext;
ULONG contextAttr;
SecBufferDesc inbuf;
SecBufferDesc outbuf;
SecBuffer OutBuffers[1];
SecBuffer InBuffers[1];
if (conn->sspictx != NULL)
{
/*
* On runs other than the first we have some data to send. Put this
* data in a SecBuffer type structure.
*/
inbuf.ulVersion = SECBUFFER_VERSION;
inbuf.cBuffers = 1;
inbuf.pBuffers = InBuffers;
InBuffers[0].pvBuffer = conn->ginbuf.value;
InBuffers[0].cbBuffer = conn->ginbuf.length;
InBuffers[0].BufferType = SECBUFFER_TOKEN;
}
OutBuffers[0].pvBuffer = NULL;
OutBuffers[0].BufferType = SECBUFFER_TOKEN;
OutBuffers[0].cbBuffer = 0;
outbuf.cBuffers = 1;
outbuf.pBuffers = OutBuffers;
outbuf.ulVersion = SECBUFFER_VERSION;
r = InitializeSecurityContext(conn->sspicred,
conn->sspictx,
conn->sspitarget,
ISC_REQ_ALLOCATE_MEMORY,
0,
SECURITY_NETWORK_DREP,
(conn->sspictx == NULL) ? NULL : &inbuf,
0,
&newContext,
&outbuf,
&contextAttr,
NULL);
if (r != SEC_E_OK && r != SEC_I_CONTINUE_NEEDED)
{
pg_SSPI_error(conn, libpq_gettext("SSPI continuation error"), r);
return STATUS_ERROR;
}
if (conn->sspictx == NULL)
{
/* On first run, transfer retrieved context handle */
conn->sspictx = malloc(sizeof(CtxtHandle));
if (conn->sspictx == NULL)
{
printfPQExpBuffer(&conn->errorMessage, libpq_gettext("out of memory\n"));
return STATUS_ERROR;
}
memcpy(conn->sspictx, &newContext, sizeof(CtxtHandle));
}
else
{
/*
* On subsequent runs when we had data to send, free buffers that
* contained this data.
*/
free(conn->ginbuf.value);
conn->ginbuf.value = NULL;
conn->ginbuf.length = 0;
}
/*
* If SSPI returned any data to be sent to the server (as it normally
* would), send this data as a password packet.
*/
if (outbuf.cBuffers > 0)
{
if (outbuf.cBuffers != 1)
{
/*
* This should never happen, at least not for Kerberos
* authentication. Keep check in case it shows up with other
* authentication methods later.
*/
printfPQExpBuffer(&conn->errorMessage, "SSPI returned invalid number of output buffers\n");
return STATUS_ERROR;
}
/*
* If the negotiation is complete, there may be zero bytes to send.
* The server is at this point not expecting any more data, so don't
* send it.
*/
if (outbuf.pBuffers[0].cbBuffer > 0)
{
if (pqPacketSend(conn, 'p',
outbuf.pBuffers[0].pvBuffer, outbuf.pBuffers[0].cbBuffer))
{
FreeContextBuffer(outbuf.pBuffers[0].pvBuffer);
return STATUS_ERROR;
}
}
FreeContextBuffer(outbuf.pBuffers[0].pvBuffer);
}
/* Cleanup is handled by the code in freePGconn() */
return STATUS_OK;
}
/*
* Send initial SSPI authentication token.
* If use_negotiate is 0, use kerberos authentication package which is
* compatible with Unix. If use_negotiate is 1, use the negotiate package
* which supports both kerberos and NTLM, but is not compatible with Unix.
*/
static int
pg_SSPI_startup(PGconn *conn, int use_negotiate)
{
SECURITY_STATUS r;
TimeStamp expire;
conn->sspictx = NULL;
/*
* Retrieve credentials handle
*/
conn->sspicred = malloc(sizeof(CredHandle));
if (conn->sspicred == NULL)
{
printfPQExpBuffer(&conn->errorMessage, libpq_gettext("out of memory\n"));
return STATUS_ERROR;
}
r = AcquireCredentialsHandle(NULL,
use_negotiate ? "negotiate" : "kerberos",
SECPKG_CRED_OUTBOUND,
NULL,
NULL,
NULL,
NULL,
conn->sspicred,
&expire);
if (r != SEC_E_OK)
{
pg_SSPI_error(conn, libpq_gettext("could not acquire SSPI credentials"), r);
free(conn->sspicred);
conn->sspicred = NULL;
return STATUS_ERROR;
}
/*
* Compute target principal name. SSPI has a different format from GSSAPI,
* but not more complex. We can skip the @REALM part, because Windows will
* fill that in for us automatically.
*/
if (!(conn->pghost && conn->pghost[0] != '\0'))
{
printfPQExpBuffer(&conn->errorMessage,
libpq_gettext("host name must be specified\n"));
return STATUS_ERROR;
}
conn->sspitarget = malloc(strlen(conn->krbsrvname) + strlen(conn->pghost) + 2);
if (!conn->sspitarget)
{
printfPQExpBuffer(&conn->errorMessage, libpq_gettext("out of memory\n"));
return STATUS_ERROR;
}
sprintf(conn->sspitarget, "%s/%s", conn->krbsrvname, conn->pghost);
/*
* Indicate that we're in SSPI authentication mode to make sure that
* pg_SSPI_continue is called next time in the negotiation.
*/
conn->usesspi = 1;
return pg_SSPI_continue(conn);
}
#endif /* ENABLE_SSPI */
/*
* Respond to AUTH_REQ_SCM_CREDS challenge.
*
* Note: this is dead code as of Postgres 9.1, because current backends will
* never send this challenge. But we must keep it as long as libpq needs to
* interoperate with pre-9.1 servers. It is believed to be needed only on
* Debian/kFreeBSD (ie, FreeBSD kernel with Linux userland, so that the
* getpeereid() function isn't provided by libc).
*/
static int
pg_local_sendauth(PGconn *conn)
{
#ifdef HAVE_STRUCT_CMSGCRED
char buf;
struct iovec iov;
struct msghdr msg;
struct cmsghdr *cmsg;
union
{
struct cmsghdr hdr;
unsigned char buf[CMSG_SPACE(sizeof(struct cmsgcred))];
} cmsgbuf;
/*
* The backend doesn't care what we send here, but it wants exactly one
* character to force recvmsg() to block and wait for us.
*/
buf = '\0';
iov.iov_base = &buf;
iov.iov_len = 1;
memset(&msg, 0, sizeof(msg));
msg.msg_iov = &iov;
msg.msg_iovlen = 1;
/* We must set up a message that will be filled in by kernel */
memset(&cmsgbuf, 0, sizeof(cmsgbuf));
msg.msg_control = &cmsgbuf.buf;
msg.msg_controllen = sizeof(cmsgbuf.buf);
cmsg = CMSG_FIRSTHDR(&msg);
cmsg->cmsg_len = CMSG_LEN(sizeof(struct cmsgcred));
cmsg->cmsg_level = SOL_SOCKET;
cmsg->cmsg_type = SCM_CREDS;
if (sendmsg(conn->sock, &msg, 0) == -1)
{
char sebuf[256];
printfPQExpBuffer(&conn->errorMessage,
"pg_local_sendauth: sendmsg: %s\n",
pqStrerror(errno, sebuf, sizeof(sebuf)));
return STATUS_ERROR;
}
return STATUS_OK;
#else
printfPQExpBuffer(&conn->errorMessage,
libpq_gettext("SCM_CRED authentication method not supported\n"));
return STATUS_ERROR;
#endif
}
static int
pg_password_sendauth(PGconn *conn, const char *password, AuthRequest areq)
{
int ret;
char *crypt_pwd = NULL;
const char *pwd_to_send;
/* Encrypt the password if needed. */
switch (areq)
{
case AUTH_REQ_MD5:
{
char *crypt_pwd2;
/* Allocate enough space for two MD5 hashes */
crypt_pwd = malloc(2 * (MD5_PASSWD_LEN + 1));
if (!crypt_pwd)
{
printfPQExpBuffer(&conn->errorMessage,
libpq_gettext("out of memory\n"));
return STATUS_ERROR;
}
crypt_pwd2 = crypt_pwd + MD5_PASSWD_LEN + 1;
if (!pg_md5_encrypt(password, conn->pguser,
strlen(conn->pguser), crypt_pwd2))
{
free(crypt_pwd);
return STATUS_ERROR;
}
if (!pg_md5_encrypt(crypt_pwd2 + strlen("md5"), conn->md5Salt,
sizeof(conn->md5Salt), crypt_pwd))
{
free(crypt_pwd);
return STATUS_ERROR;
}
pwd_to_send = crypt_pwd;
break;
}
case AUTH_REQ_PASSWORD:
pwd_to_send = password;
break;
default:
return STATUS_ERROR;
}
/* Packet has a message type as of protocol 3.0 */
if (PG_PROTOCOL_MAJOR(conn->pversion) >= 3)
ret = pqPacketSend(conn, 'p', pwd_to_send, strlen(pwd_to_send) + 1);
else
ret = pqPacketSend(conn, 0, pwd_to_send, strlen(pwd_to_send) + 1);
if (crypt_pwd)
free(crypt_pwd);
return ret;
}
/*
* pg_fe_sendauth
* client demux routine for outgoing authentication information
*/
int
pg_fe_sendauth(AuthRequest areq, PGconn *conn)
{
switch (areq)
{
case AUTH_REQ_OK:
break;
case AUTH_REQ_KRB4:
printfPQExpBuffer(&conn->errorMessage,
libpq_gettext("Kerberos 4 authentication not supported\n"));
return STATUS_ERROR;
case AUTH_REQ_KRB5:
printfPQExpBuffer(&conn->errorMessage,
libpq_gettext("Kerberos 5 authentication not supported\n"));
return STATUS_ERROR;
#if defined(ENABLE_GSS) || defined(ENABLE_SSPI)
case AUTH_REQ_GSS:
#if !defined(ENABLE_SSPI)
/* no native SSPI, so use GSSAPI library for it */
case AUTH_REQ_SSPI:
#endif
{
int r;
pglock_thread();
/*
* If we have both GSS and SSPI support compiled in, use SSPI
* support by default. This is overridable by a connection
* string parameter. Note that when using SSPI we still leave
* the negotiate parameter off, since we want SSPI to use the
* GSSAPI kerberos protocol. For actual SSPI negotiate
* protocol, we use AUTH_REQ_SSPI.
*/
#if defined(ENABLE_GSS) && defined(ENABLE_SSPI)
if (conn->gsslib && (pg_strcasecmp(conn->gsslib, "gssapi") == 0))
r = pg_GSS_startup(conn);
else
r = pg_SSPI_startup(conn, 0);
#elif defined(ENABLE_GSS) && !defined(ENABLE_SSPI)
r = pg_GSS_startup(conn);
#elif !defined(ENABLE_GSS) && defined(ENABLE_SSPI)
r = pg_SSPI_startup(conn, 0);
#endif
if (r != STATUS_OK)
{
/* Error message already filled in. */
pgunlock_thread();
return STATUS_ERROR;
}
pgunlock_thread();
}
break;
case AUTH_REQ_GSS_CONT:
{
int r;
pglock_thread();
#if defined(ENABLE_GSS) && defined(ENABLE_SSPI)
if (conn->usesspi)
r = pg_SSPI_continue(conn);
else
r = pg_GSS_continue(conn);
#elif defined(ENABLE_GSS) && !defined(ENABLE_SSPI)
r = pg_GSS_continue(conn);
#elif !defined(ENABLE_GSS) && defined(ENABLE_SSPI)
r = pg_SSPI_continue(conn);
#endif
if (r != STATUS_OK)
{
/* Error message already filled in. */
pgunlock_thread();
return STATUS_ERROR;
}
pgunlock_thread();
}
break;
#else /* defined(ENABLE_GSS) || defined(ENABLE_SSPI) */
/* No GSSAPI *or* SSPI support */
case AUTH_REQ_GSS:
case AUTH_REQ_GSS_CONT:
printfPQExpBuffer(&conn->errorMessage,
libpq_gettext("GSSAPI authentication not supported\n"));
return STATUS_ERROR;
#endif /* defined(ENABLE_GSS) || defined(ENABLE_SSPI) */
#ifdef ENABLE_SSPI
case AUTH_REQ_SSPI:
/*
* SSPI has it's own startup message so libpq can decide which
* method to use. Indicate to pg_SSPI_startup that we want SSPI
* negotiation instead of Kerberos.
*/
pglock_thread();
if (pg_SSPI_startup(conn, 1) != STATUS_OK)
{
/* Error message already filled in. */
pgunlock_thread();
return STATUS_ERROR;
}
pgunlock_thread();
break;
#else
/*
* No SSPI support. However, if we have GSSAPI but not SSPI
* support, AUTH_REQ_SSPI will have been handled in the codepath
* for AUTH_REQ_GSSAPI above, so don't duplicate the case label in
* that case.
*/
#if !defined(ENABLE_GSS)
case AUTH_REQ_SSPI:
printfPQExpBuffer(&conn->errorMessage,
libpq_gettext("SSPI authentication not supported\n"));
return STATUS_ERROR;
#endif /* !define(ENABLE_GSSAPI) */
#endif /* ENABLE_SSPI */
case AUTH_REQ_CRYPT:
printfPQExpBuffer(&conn->errorMessage,
libpq_gettext("Crypt authentication not supported\n"));
return STATUS_ERROR;
case AUTH_REQ_MD5:
case AUTH_REQ_PASSWORD:
conn->password_needed = true;
if (conn->pgpass == NULL || conn->pgpass[0] == '\0')
{
printfPQExpBuffer(&conn->errorMessage,
PQnoPasswordSupplied);
return STATUS_ERROR;
}
if (pg_password_sendauth(conn, conn->pgpass, areq) != STATUS_OK)
{
printfPQExpBuffer(&conn->errorMessage,
"fe_sendauth: error sending password authentication\n");
return STATUS_ERROR;
}
break;
case AUTH_REQ_SCM_CREDS:
if (pg_local_sendauth(conn) != STATUS_OK)
return STATUS_ERROR;
break;
default:
printfPQExpBuffer(&conn->errorMessage,
libpq_gettext("authentication method %u not supported\n"), areq);
return STATUS_ERROR;
}
return STATUS_OK;
}
/*
* pg_fe_getauthname
*
* Returns a pointer to malloc'd space containing whatever name the user
* has authenticated to the system. If there is an error, return NULL,
* and put a suitable error message in *errorMessage if that's not NULL.
*/
char *
pg_fe_getauthname(PQExpBuffer errorMessage)
{
char *result = NULL;
const char *name = NULL;
#ifdef WIN32
/* Microsoft recommends buffer size of UNLEN+1, where UNLEN = 256 */
char username[256 + 1];
DWORD namesize = sizeof(username);
#else
uid_t user_id = geteuid();
char pwdbuf[BUFSIZ];
struct passwd pwdstr;
struct passwd *pw = NULL;
int pwerr;
#endif
/*
* Some users are using configure --enable-thread-safety-force, so we
* might as well do the locking within our library to protect
* pqGetpwuid(). In fact, application developers can use getpwuid() in
* their application if they use the locking call we provide, or install
* their own locking function using PQregisterThreadLock().
*/
pglock_thread();
#ifdef WIN32
if (GetUserName(username, &namesize))
name = username;
else if (errorMessage)
printfPQExpBuffer(errorMessage,
libpq_gettext("user name lookup failure: error code %lu\n"),
GetLastError());
#else
pwerr = pqGetpwuid(user_id, &pwdstr, pwdbuf, sizeof(pwdbuf), &pw);
if (pw != NULL)
name = pw->pw_name;
else if (errorMessage)
{
if (pwerr != 0)
printfPQExpBuffer(errorMessage,
libpq_gettext("could not look up local user ID %d: %s\n"),
(int) user_id,
pqStrerror(pwerr, pwdbuf, sizeof(pwdbuf)));
else
printfPQExpBuffer(errorMessage,
libpq_gettext("local user with ID %d does not exist\n"),
(int) user_id);
}
#endif
if (name)
{
result = strdup(name);
if (result == NULL && errorMessage)
printfPQExpBuffer(errorMessage,
libpq_gettext("out of memory\n"));
}
pgunlock_thread();
return result;
}
/*
* PQencryptPassword -- exported routine to encrypt a password
*
* This is intended to be used by client applications that wish to send
* commands like ALTER USER joe PASSWORD 'pwd'. The password need not
* be sent in cleartext if it is encrypted on the client side. This is
* good because it ensures the cleartext password won't end up in logs,
* pg_stat displays, etc. We export the function so that clients won't
* be dependent on low-level details like whether the enceyption is MD5
* or something else.
*
* Arguments are the cleartext password, and the SQL name of the user it
* is for.
*
* Return value is a malloc'd string, or NULL if out-of-memory. The client
* may assume the string doesn't contain any special characters that would
* require escaping.
*/
char *
PQencryptPassword(const char *passwd, const char *user)
{
char *crypt_pwd;
crypt_pwd = malloc(MD5_PASSWD_LEN + 1);
if (!crypt_pwd)
return NULL;
if (!pg_md5_encrypt(passwd, user, strlen(user), crypt_pwd))
{
free(crypt_pwd);
return NULL;
}
return crypt_pwd;
}