/*------------------------------------------------------------------------- * * fe-auth.c * The front-end (client) authorization routines * * Portions Copyright (c) 1996-2016, 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 #include #include /* for MAXHOSTNAMELEN on most */ #include #ifdef HAVE_SYS_UCRED_H #include #endif #ifndef MAXHOSTNAMELEN #include /* for MAXHOSTNAMELEN on some */ #endif #include #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_IGNORE_INSERTS | 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; if (conn->sspictx) { printfPQExpBuffer(&conn->errorMessage, libpq_gettext("duplicate SSPI authentication request\n")); return STATUS_ERROR; } /* * 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; /* * SASL authentication was introduced in version 10. Older * versions recognize the request only to give a nicer error * message. We call it "SCRAM authentication" in the error, rather * than SASL, because SCRAM is more familiar to users, and it's * the only SASL authentication mechanism that has been * implemented as of this writing, anyway. */ case AUTH_REQ_SASL: printfPQExpBuffer(&conn->errorMessage, libpq_gettext("SCRAM authentication requires libpq version 10 or above\n")); return STATUS_ERROR; 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 encryption 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; }