|  | /* | 
|  | * QEMU VNC display driver: SASL auth protocol | 
|  | * | 
|  | * Copyright (C) 2009 Red Hat, Inc | 
|  | * | 
|  | * Permission is hereby granted, free of charge, to any person obtaining a copy | 
|  | * of this software and associated documentation files (the "Software"), to deal | 
|  | * in the Software without restriction, including without limitation the rights | 
|  | * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell | 
|  | * copies of the Software, and to permit persons to whom the Software is | 
|  | * furnished to do so, subject to the following conditions: | 
|  | * | 
|  | * The above copyright notice and this permission notice shall be included in | 
|  | * all copies or substantial portions of the Software. | 
|  | * | 
|  | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR | 
|  | * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, | 
|  | * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL | 
|  | * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER | 
|  | * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, | 
|  | * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN | 
|  | * THE SOFTWARE. | 
|  | */ | 
|  |  | 
|  | #include "qemu/osdep.h" | 
|  | #include "qapi/error.h" | 
|  | #include "authz/base.h" | 
|  | #include "vnc.h" | 
|  | #include "trace.h" | 
|  |  | 
|  | /* | 
|  | * Apple has deprecated sasl.h functions in OS X 10.11.  Therefore, | 
|  | * files that use SASL API need to disable -Wdeprecated-declarations. | 
|  | */ | 
|  | #ifdef CONFIG_DARWIN | 
|  | #pragma GCC diagnostic ignored "-Wdeprecated-declarations" | 
|  | #endif | 
|  |  | 
|  | /* Max amount of data we send/recv for SASL steps to prevent DOS */ | 
|  | #define SASL_DATA_MAX_LEN (1024 * 1024) | 
|  |  | 
|  |  | 
|  | bool vnc_sasl_server_init(Error **errp) | 
|  | { | 
|  | int saslErr = sasl_server_init(NULL, "qemu"); | 
|  |  | 
|  | if (saslErr != SASL_OK) { | 
|  | error_setg(errp, "Failed to initialize SASL auth: %s", | 
|  | sasl_errstring(saslErr, NULL, NULL)); | 
|  | return false; | 
|  | } | 
|  | return true; | 
|  | } | 
|  |  | 
|  | void vnc_sasl_client_cleanup(VncState *vs) | 
|  | { | 
|  | if (vs->sasl.conn) { | 
|  | vs->sasl.runSSF = false; | 
|  | vs->sasl.wantSSF = false; | 
|  | vs->sasl.waitWriteSSF = 0; | 
|  | vs->sasl.encodedLength = vs->sasl.encodedOffset = 0; | 
|  | vs->sasl.encoded = NULL; | 
|  | g_free(vs->sasl.username); | 
|  | g_free(vs->sasl.mechlist); | 
|  | vs->sasl.username = vs->sasl.mechlist = NULL; | 
|  | sasl_dispose(&vs->sasl.conn); | 
|  | vs->sasl.conn = NULL; | 
|  | } | 
|  | } | 
|  |  | 
|  |  | 
|  | size_t vnc_client_write_sasl(VncState *vs) | 
|  | { | 
|  | size_t ret; | 
|  |  | 
|  | VNC_DEBUG("Write SASL: Pending output %p size %zd offset %zd " | 
|  | "Encoded: %p size %d offset %d\n", | 
|  | vs->output.buffer, vs->output.capacity, vs->output.offset, | 
|  | vs->sasl.encoded, vs->sasl.encodedLength, vs->sasl.encodedOffset); | 
|  |  | 
|  | if (!vs->sasl.encoded) { | 
|  | int err; | 
|  | err = sasl_encode(vs->sasl.conn, | 
|  | (char *)vs->output.buffer, | 
|  | vs->output.offset, | 
|  | (const char **)&vs->sasl.encoded, | 
|  | &vs->sasl.encodedLength); | 
|  | if (err != SASL_OK) | 
|  | return vnc_client_io_error(vs, -1, NULL); | 
|  |  | 
|  | vs->sasl.encodedRawLength = vs->output.offset; | 
|  | vs->sasl.encodedOffset = 0; | 
|  | } | 
|  |  | 
|  | ret = vnc_client_write_buf(vs, | 
|  | vs->sasl.encoded + vs->sasl.encodedOffset, | 
|  | vs->sasl.encodedLength - vs->sasl.encodedOffset); | 
|  | if (!ret) | 
|  | return 0; | 
|  |  | 
|  | vs->sasl.encodedOffset += ret; | 
|  | if (vs->sasl.encodedOffset == vs->sasl.encodedLength) { | 
|  | bool throttled = vs->force_update_offset != 0; | 
|  | size_t offset; | 
|  | if (vs->sasl.encodedRawLength >= vs->force_update_offset) { | 
|  | vs->force_update_offset = 0; | 
|  | } else { | 
|  | vs->force_update_offset -= vs->sasl.encodedRawLength; | 
|  | } | 
|  | if (throttled && vs->force_update_offset == 0) { | 
|  | trace_vnc_client_unthrottle_forced(vs, vs->ioc); | 
|  | } | 
|  | offset = vs->output.offset; | 
|  | buffer_advance(&vs->output, vs->sasl.encodedRawLength); | 
|  | if (offset >= vs->throttle_output_offset && | 
|  | vs->output.offset < vs->throttle_output_offset) { | 
|  | trace_vnc_client_unthrottle_incremental(vs, vs->ioc, | 
|  | vs->output.offset); | 
|  | } | 
|  | vs->sasl.encoded = NULL; | 
|  | vs->sasl.encodedOffset = vs->sasl.encodedLength = 0; | 
|  | } | 
|  |  | 
|  | /* Can't merge this block with one above, because | 
|  | * someone might have written more unencrypted | 
|  | * data in vs->output while we were processing | 
|  | * SASL encoded output | 
|  | */ | 
|  | if (vs->output.offset == 0) { | 
|  | if (vs->ioc_tag) { | 
|  | g_source_remove(vs->ioc_tag); | 
|  | } | 
|  | vs->ioc_tag = qio_channel_add_watch( | 
|  | vs->ioc, G_IO_IN | G_IO_HUP | G_IO_ERR, | 
|  | vnc_client_io, vs, NULL); | 
|  | } | 
|  |  | 
|  | return ret; | 
|  | } | 
|  |  | 
|  |  | 
|  | size_t vnc_client_read_sasl(VncState *vs) | 
|  | { | 
|  | size_t ret; | 
|  | uint8_t encoded[4096]; | 
|  | const char *decoded; | 
|  | unsigned int decodedLen; | 
|  | int err; | 
|  |  | 
|  | ret = vnc_client_read_buf(vs, encoded, sizeof(encoded)); | 
|  | if (!ret) | 
|  | return 0; | 
|  |  | 
|  | err = sasl_decode(vs->sasl.conn, | 
|  | (char *)encoded, ret, | 
|  | &decoded, &decodedLen); | 
|  |  | 
|  | if (err != SASL_OK) | 
|  | return vnc_client_io_error(vs, -1, NULL); | 
|  | VNC_DEBUG("Read SASL Encoded %p size %ld Decoded %p size %d\n", | 
|  | encoded, ret, decoded, decodedLen); | 
|  | buffer_reserve(&vs->input, decodedLen); | 
|  | buffer_append(&vs->input, decoded, decodedLen); | 
|  | return decodedLen; | 
|  | } | 
|  |  | 
|  |  | 
|  | static int vnc_auth_sasl_check_access(VncState *vs) | 
|  | { | 
|  | const void *val; | 
|  | int rv; | 
|  | Error *err = NULL; | 
|  | bool allow; | 
|  |  | 
|  | rv = sasl_getprop(vs->sasl.conn, SASL_USERNAME, &val); | 
|  | if (rv != SASL_OK) { | 
|  | trace_vnc_auth_fail(vs, vs->auth, "Cannot fetch SASL username", | 
|  | sasl_errstring(rv, NULL, NULL)); | 
|  | return -1; | 
|  | } | 
|  | if (val == NULL) { | 
|  | trace_vnc_auth_fail(vs, vs->auth, "No SASL username set", ""); | 
|  | return -1; | 
|  | } | 
|  |  | 
|  | vs->sasl.username = g_strdup((const char*)val); | 
|  | trace_vnc_auth_sasl_username(vs, vs->sasl.username); | 
|  |  | 
|  | if (vs->vd->sasl.authzid == NULL) { | 
|  | trace_vnc_auth_sasl_acl(vs, 1); | 
|  | return 0; | 
|  | } | 
|  |  | 
|  | allow = qauthz_is_allowed_by_id(vs->vd->sasl.authzid, | 
|  | vs->sasl.username, &err); | 
|  | if (err) { | 
|  | trace_vnc_auth_fail(vs, vs->auth, "Error from authz", | 
|  | error_get_pretty(err)); | 
|  | error_free(err); | 
|  | return -1; | 
|  | } | 
|  |  | 
|  | trace_vnc_auth_sasl_acl(vs, allow); | 
|  | return allow ? 0 : -1; | 
|  | } | 
|  |  | 
|  | static int vnc_auth_sasl_check_ssf(VncState *vs) | 
|  | { | 
|  | const void *val; | 
|  | int err, ssf; | 
|  |  | 
|  | if (!vs->sasl.wantSSF) | 
|  | return 1; | 
|  |  | 
|  | err = sasl_getprop(vs->sasl.conn, SASL_SSF, &val); | 
|  | if (err != SASL_OK) | 
|  | return 0; | 
|  |  | 
|  | ssf = *(const int *)val; | 
|  |  | 
|  | trace_vnc_auth_sasl_ssf(vs, ssf); | 
|  |  | 
|  | if (ssf < 56) | 
|  | return 0; /* 56 is good for Kerberos */ | 
|  |  | 
|  | /* Only setup for read initially, because we're about to send an RPC | 
|  | * reply which must be in plain text. When the next incoming RPC | 
|  | * arrives, we'll switch on writes too | 
|  | * | 
|  | * cf qemudClientReadSASL  in qemud.c | 
|  | */ | 
|  | vs->sasl.runSSF = 1; | 
|  |  | 
|  | /* We have a SSF that's good enough */ | 
|  | return 1; | 
|  | } | 
|  |  | 
|  | /* | 
|  | * Step Msg | 
|  | * | 
|  | * Input from client: | 
|  | * | 
|  | * u32 clientin-length | 
|  | * u8-array clientin-string | 
|  | * | 
|  | * Output to client: | 
|  | * | 
|  | * u32 serverout-length | 
|  | * u8-array serverout-strin | 
|  | * u8 continue | 
|  | */ | 
|  |  | 
|  | static int protocol_client_auth_sasl_step_len(VncState *vs, uint8_t *data, size_t len); | 
|  |  | 
|  | static int protocol_client_auth_sasl_step(VncState *vs, uint8_t *data, size_t len) | 
|  | { | 
|  | uint32_t datalen = len; | 
|  | const char *serverout; | 
|  | unsigned int serveroutlen; | 
|  | int err; | 
|  | char *clientdata = NULL; | 
|  |  | 
|  | /* NB, distinction of NULL vs "" is *critical* in SASL */ | 
|  | if (datalen) { | 
|  | clientdata = (char*)data; | 
|  | if (clientdata[datalen - 1] != '\0') { | 
|  | trace_vnc_auth_fail(vs, vs->auth, "Malformed SASL client data", | 
|  | "Missing SASL NUL padding byte"); | 
|  | sasl_dispose(&vs->sasl.conn); | 
|  | vs->sasl.conn = NULL; | 
|  | goto authabort; | 
|  | } | 
|  | datalen--; /* Discard the extra NUL padding byte */ | 
|  | } | 
|  |  | 
|  | err = sasl_server_step(vs->sasl.conn, | 
|  | clientdata, | 
|  | datalen, | 
|  | &serverout, | 
|  | &serveroutlen); | 
|  | trace_vnc_auth_sasl_step(vs, data, len, serverout, serveroutlen, err); | 
|  | if (err != SASL_OK && | 
|  | err != SASL_CONTINUE) { | 
|  | trace_vnc_auth_fail(vs, vs->auth, "Cannot step SASL auth", | 
|  | sasl_errdetail(vs->sasl.conn)); | 
|  | sasl_dispose(&vs->sasl.conn); | 
|  | vs->sasl.conn = NULL; | 
|  | goto authabort; | 
|  | } | 
|  |  | 
|  | if (serveroutlen > SASL_DATA_MAX_LEN) { | 
|  | trace_vnc_auth_fail(vs, vs->auth, "SASL data too long", ""); | 
|  | sasl_dispose(&vs->sasl.conn); | 
|  | vs->sasl.conn = NULL; | 
|  | goto authabort; | 
|  | } | 
|  |  | 
|  | if (serverout) { | 
|  | vnc_write_u32(vs, serveroutlen + 1); | 
|  | vnc_write(vs, serverout, serveroutlen); | 
|  | vnc_write_u8(vs, '\0'); | 
|  | } else { | 
|  | vnc_write_u32(vs, 0); | 
|  | } | 
|  |  | 
|  | /* Whether auth is complete */ | 
|  | vnc_write_u8(vs, err == SASL_CONTINUE ? 0 : 1); | 
|  |  | 
|  | if (err == SASL_CONTINUE) { | 
|  | /* Wait for step length */ | 
|  | vnc_read_when(vs, protocol_client_auth_sasl_step_len, 4); | 
|  | } else { | 
|  | if (!vnc_auth_sasl_check_ssf(vs)) { | 
|  | trace_vnc_auth_fail(vs, vs->auth, "SASL SSF too weak", ""); | 
|  | goto authreject; | 
|  | } | 
|  |  | 
|  | /* Check the username access control list */ | 
|  | if (vnc_auth_sasl_check_access(vs) < 0) { | 
|  | goto authreject; | 
|  | } | 
|  |  | 
|  | trace_vnc_auth_pass(vs, vs->auth); | 
|  | vnc_write_u32(vs, 0); /* Accept auth */ | 
|  | /* | 
|  | * Delay writing in SSF encoded mode until pending output | 
|  | * buffer is written | 
|  | */ | 
|  | if (vs->sasl.runSSF) | 
|  | vs->sasl.waitWriteSSF = vs->output.offset; | 
|  | start_client_init(vs); | 
|  | } | 
|  |  | 
|  | return 0; | 
|  |  | 
|  | authreject: | 
|  | vnc_write_u32(vs, 1); /* Reject auth */ | 
|  | vnc_write_u32(vs, sizeof("Authentication failed")); | 
|  | vnc_write(vs, "Authentication failed", sizeof("Authentication failed")); | 
|  | vnc_flush(vs); | 
|  | vnc_client_error(vs); | 
|  | return -1; | 
|  |  | 
|  | authabort: | 
|  | vnc_client_error(vs); | 
|  | return -1; | 
|  | } | 
|  |  | 
|  | static int protocol_client_auth_sasl_step_len(VncState *vs, uint8_t *data, size_t len) | 
|  | { | 
|  | uint32_t steplen = read_u32(data, 0); | 
|  |  | 
|  | if (steplen > SASL_DATA_MAX_LEN) { | 
|  | trace_vnc_auth_fail(vs, vs->auth, "SASL step len too large", ""); | 
|  | vnc_client_error(vs); | 
|  | return -1; | 
|  | } | 
|  |  | 
|  | if (steplen == 0) | 
|  | return protocol_client_auth_sasl_step(vs, NULL, 0); | 
|  | else | 
|  | vnc_read_when(vs, protocol_client_auth_sasl_step, steplen); | 
|  | return 0; | 
|  | } | 
|  |  | 
|  | /* | 
|  | * Start Msg | 
|  | * | 
|  | * Input from client: | 
|  | * | 
|  | * u32 clientin-length | 
|  | * u8-array clientin-string | 
|  | * | 
|  | * Output to client: | 
|  | * | 
|  | * u32 serverout-length | 
|  | * u8-array serverout-strin | 
|  | * u8 continue | 
|  | */ | 
|  |  | 
|  | #define SASL_DATA_MAX_LEN (1024 * 1024) | 
|  |  | 
|  | static int protocol_client_auth_sasl_start(VncState *vs, uint8_t *data, size_t len) | 
|  | { | 
|  | uint32_t datalen = len; | 
|  | const char *serverout; | 
|  | unsigned int serveroutlen; | 
|  | int err; | 
|  | char *clientdata = NULL; | 
|  |  | 
|  | /* NB, distinction of NULL vs "" is *critical* in SASL */ | 
|  | if (datalen) { | 
|  | clientdata = (char*)data; | 
|  | if (clientdata[datalen - 1] != '\0') { | 
|  | trace_vnc_auth_fail(vs, vs->auth,  "Malformed SASL client data", | 
|  | "Missing SASL NUL padding byte"); | 
|  | sasl_dispose(&vs->sasl.conn); | 
|  | vs->sasl.conn = NULL; | 
|  | goto authabort; | 
|  | } | 
|  | datalen--; /* Discard the extra NUL padding byte */ | 
|  | } | 
|  |  | 
|  | err = sasl_server_start(vs->sasl.conn, | 
|  | vs->sasl.mechlist, | 
|  | clientdata, | 
|  | datalen, | 
|  | &serverout, | 
|  | &serveroutlen); | 
|  | trace_vnc_auth_sasl_start(vs, data, len, serverout, serveroutlen, err); | 
|  | if (err != SASL_OK && | 
|  | err != SASL_CONTINUE) { | 
|  | trace_vnc_auth_fail(vs, vs->auth, "Cannot start SASL auth", | 
|  | sasl_errdetail(vs->sasl.conn)); | 
|  | sasl_dispose(&vs->sasl.conn); | 
|  | vs->sasl.conn = NULL; | 
|  | goto authabort; | 
|  | } | 
|  | if (serveroutlen > SASL_DATA_MAX_LEN) { | 
|  | trace_vnc_auth_fail(vs, vs->auth, "SASL data too long", ""); | 
|  | sasl_dispose(&vs->sasl.conn); | 
|  | vs->sasl.conn = NULL; | 
|  | goto authabort; | 
|  | } | 
|  |  | 
|  | if (serverout) { | 
|  | vnc_write_u32(vs, serveroutlen + 1); | 
|  | vnc_write(vs, serverout, serveroutlen); | 
|  | vnc_write_u8(vs, '\0'); | 
|  | } else { | 
|  | vnc_write_u32(vs, 0); | 
|  | } | 
|  |  | 
|  | /* Whether auth is complete */ | 
|  | vnc_write_u8(vs, err == SASL_CONTINUE ? 0 : 1); | 
|  |  | 
|  | if (err == SASL_CONTINUE) { | 
|  | /* Wait for step length */ | 
|  | vnc_read_when(vs, protocol_client_auth_sasl_step_len, 4); | 
|  | } else { | 
|  | if (!vnc_auth_sasl_check_ssf(vs)) { | 
|  | trace_vnc_auth_fail(vs, vs->auth, "SASL SSF too weak", ""); | 
|  | goto authreject; | 
|  | } | 
|  |  | 
|  | /* Check the username access control list */ | 
|  | if (vnc_auth_sasl_check_access(vs) < 0) { | 
|  | goto authreject; | 
|  | } | 
|  |  | 
|  | trace_vnc_auth_pass(vs, vs->auth); | 
|  | vnc_write_u32(vs, 0); /* Accept auth */ | 
|  | start_client_init(vs); | 
|  | } | 
|  |  | 
|  | return 0; | 
|  |  | 
|  | authreject: | 
|  | vnc_write_u32(vs, 1); /* Reject auth */ | 
|  | vnc_write_u32(vs, sizeof("Authentication failed")); | 
|  | vnc_write(vs, "Authentication failed", sizeof("Authentication failed")); | 
|  | vnc_flush(vs); | 
|  | vnc_client_error(vs); | 
|  | return -1; | 
|  |  | 
|  | authabort: | 
|  | vnc_client_error(vs); | 
|  | return -1; | 
|  | } | 
|  |  | 
|  | static int protocol_client_auth_sasl_start_len(VncState *vs, uint8_t *data, size_t len) | 
|  | { | 
|  | uint32_t startlen = read_u32(data, 0); | 
|  |  | 
|  | if (startlen > SASL_DATA_MAX_LEN) { | 
|  | trace_vnc_auth_fail(vs, vs->auth, "SASL start len too large", ""); | 
|  | vnc_client_error(vs); | 
|  | return -1; | 
|  | } | 
|  |  | 
|  | if (startlen == 0) | 
|  | return protocol_client_auth_sasl_start(vs, NULL, 0); | 
|  |  | 
|  | vnc_read_when(vs, protocol_client_auth_sasl_start, startlen); | 
|  | return 0; | 
|  | } | 
|  |  | 
|  | static int protocol_client_auth_sasl_mechname(VncState *vs, uint8_t *data, size_t len) | 
|  | { | 
|  | char *mechname = g_strndup((const char *) data, len); | 
|  | trace_vnc_auth_sasl_mech_choose(vs, mechname); | 
|  |  | 
|  | if (strncmp(vs->sasl.mechlist, mechname, len) == 0) { | 
|  | if (vs->sasl.mechlist[len] != '\0' && | 
|  | vs->sasl.mechlist[len] != ',') { | 
|  | goto fail; | 
|  | } | 
|  | } else { | 
|  | char *offset = strstr(vs->sasl.mechlist, mechname); | 
|  | if (!offset) { | 
|  | goto fail; | 
|  | } | 
|  | if (offset[-1] != ',' || | 
|  | (offset[len] != '\0'&& | 
|  | offset[len] != ',')) { | 
|  | goto fail; | 
|  | } | 
|  | } | 
|  |  | 
|  | g_free(vs->sasl.mechlist); | 
|  | vs->sasl.mechlist = mechname; | 
|  |  | 
|  | vnc_read_when(vs, protocol_client_auth_sasl_start_len, 4); | 
|  | return 0; | 
|  |  | 
|  | fail: | 
|  | trace_vnc_auth_fail(vs, vs->auth, "Unsupported mechname", mechname); | 
|  | vnc_client_error(vs); | 
|  | g_free(mechname); | 
|  | return -1; | 
|  | } | 
|  |  | 
|  | static int protocol_client_auth_sasl_mechname_len(VncState *vs, uint8_t *data, size_t len) | 
|  | { | 
|  | uint32_t mechlen = read_u32(data, 0); | 
|  |  | 
|  | if (mechlen > 100) { | 
|  | trace_vnc_auth_fail(vs, vs->auth, "SASL mechname too long", ""); | 
|  | vnc_client_error(vs); | 
|  | return -1; | 
|  | } | 
|  | if (mechlen < 1) { | 
|  | trace_vnc_auth_fail(vs, vs->auth, "SASL mechname too short", ""); | 
|  | vnc_client_error(vs); | 
|  | return -1; | 
|  | } | 
|  | vnc_read_when(vs, protocol_client_auth_sasl_mechname,mechlen); | 
|  | return 0; | 
|  | } | 
|  |  | 
|  | static int | 
|  | vnc_socket_ip_addr_string(QIOChannelSocket *ioc, | 
|  | bool local, | 
|  | char **addrstr, | 
|  | Error **errp) | 
|  | { | 
|  | SocketAddress *addr; | 
|  |  | 
|  | if (local) { | 
|  | addr = qio_channel_socket_get_local_address(ioc, errp); | 
|  | } else { | 
|  | addr = qio_channel_socket_get_remote_address(ioc, errp); | 
|  | } | 
|  | if (!addr) { | 
|  | return -1; | 
|  | } | 
|  |  | 
|  | if (addr->type != SOCKET_ADDRESS_TYPE_INET) { | 
|  | *addrstr = NULL; | 
|  | qapi_free_SocketAddress(addr); | 
|  | return 0; | 
|  | } | 
|  | *addrstr = g_strdup_printf("%s;%s", addr->u.inet.host, addr->u.inet.port); | 
|  | qapi_free_SocketAddress(addr); | 
|  | return 0; | 
|  | } | 
|  |  | 
|  | static bool | 
|  | vnc_socket_is_unix(QIOChannelSocket *ioc) | 
|  | { | 
|  | SocketAddress *addr = qio_channel_socket_get_local_address(ioc, NULL); | 
|  | return addr && addr->type == SOCKET_ADDRESS_TYPE_UNIX; | 
|  | } | 
|  |  | 
|  | void start_auth_sasl(VncState *vs) | 
|  | { | 
|  | const char *mechlist = NULL; | 
|  | sasl_security_properties_t secprops; | 
|  | int err; | 
|  | Error *local_err = NULL; | 
|  | char *localAddr, *remoteAddr; | 
|  | int mechlistlen; | 
|  |  | 
|  | /* Get local & remote client addresses in form  IPADDR;PORT */ | 
|  | if (vnc_socket_ip_addr_string(vs->sioc, true, | 
|  | &localAddr, &local_err) < 0) { | 
|  | trace_vnc_auth_fail(vs, vs->auth, "Cannot format local IP", | 
|  | error_get_pretty(local_err)); | 
|  | goto authabort; | 
|  | } | 
|  |  | 
|  | if (vnc_socket_ip_addr_string(vs->sioc, false, | 
|  | &remoteAddr, &local_err) < 0) { | 
|  | trace_vnc_auth_fail(vs, vs->auth, "Cannot format remote IP", | 
|  | error_get_pretty(local_err)); | 
|  | g_free(localAddr); | 
|  | goto authabort; | 
|  | } | 
|  |  | 
|  | err = sasl_server_new("vnc", | 
|  | NULL, /* FQDN - just delegates to gethostname */ | 
|  | NULL, /* User realm */ | 
|  | localAddr, | 
|  | remoteAddr, | 
|  | NULL, /* Callbacks, not needed */ | 
|  | SASL_SUCCESS_DATA, | 
|  | &vs->sasl.conn); | 
|  | g_free(localAddr); | 
|  | g_free(remoteAddr); | 
|  | localAddr = remoteAddr = NULL; | 
|  |  | 
|  | if (err != SASL_OK) { | 
|  | trace_vnc_auth_fail(vs, vs->auth,  "SASL context setup failed", | 
|  | sasl_errstring(err, NULL, NULL)); | 
|  | vs->sasl.conn = NULL; | 
|  | goto authabort; | 
|  | } | 
|  |  | 
|  | /* Inform SASL that we've got an external SSF layer from TLS/x509 */ | 
|  | if (vs->auth == VNC_AUTH_VENCRYPT && | 
|  | vs->subauth == VNC_AUTH_VENCRYPT_X509SASL) { | 
|  | int keysize; | 
|  | sasl_ssf_t ssf; | 
|  |  | 
|  | keysize = qcrypto_tls_session_get_key_size(vs->tls, | 
|  | &local_err); | 
|  | if (keysize < 0) { | 
|  | trace_vnc_auth_fail(vs, vs->auth, "cannot TLS get cipher size", | 
|  | error_get_pretty(local_err)); | 
|  | sasl_dispose(&vs->sasl.conn); | 
|  | vs->sasl.conn = NULL; | 
|  | goto authabort; | 
|  | } | 
|  | ssf = keysize * CHAR_BIT; /* tls key size is bytes, sasl wants bits */ | 
|  |  | 
|  | err = sasl_setprop(vs->sasl.conn, SASL_SSF_EXTERNAL, &ssf); | 
|  | if (err != SASL_OK) { | 
|  | trace_vnc_auth_fail(vs, vs->auth, "cannot set SASL external SSF", | 
|  | sasl_errstring(err, NULL, NULL)); | 
|  | sasl_dispose(&vs->sasl.conn); | 
|  | vs->sasl.conn = NULL; | 
|  | goto authabort; | 
|  | } | 
|  | } else { | 
|  | vs->sasl.wantSSF = !vnc_socket_is_unix(vs->sioc); | 
|  | } | 
|  |  | 
|  | memset (&secprops, 0, sizeof secprops); | 
|  | /* Inform SASL that we've got an external SSF layer from TLS. | 
|  | * | 
|  | * Disable SSF, if using TLS+x509+SASL only, or UNIX sockets. | 
|  | * TLS without x509 is not sufficiently strong, nor is plain | 
|  | * TCP | 
|  | */ | 
|  | if (vnc_socket_is_unix(vs->sioc) || | 
|  | (vs->auth == VNC_AUTH_VENCRYPT && | 
|  | vs->subauth == VNC_AUTH_VENCRYPT_X509SASL)) { | 
|  | /* If we've got TLS or UNIX domain sock, we don't care about SSF */ | 
|  | secprops.min_ssf = 0; | 
|  | secprops.max_ssf = 0; | 
|  | secprops.maxbufsize = 8192; | 
|  | secprops.security_flags = 0; | 
|  | } else { | 
|  | /* Plain TCP, better get an SSF layer */ | 
|  | secprops.min_ssf = 56; /* Good enough to require kerberos */ | 
|  | secprops.max_ssf = 100000; /* Arbitrary big number */ | 
|  | secprops.maxbufsize = 8192; | 
|  | /* Forbid any anonymous or trivially crackable auth */ | 
|  | secprops.security_flags = | 
|  | SASL_SEC_NOANONYMOUS | SASL_SEC_NOPLAINTEXT; | 
|  | } | 
|  |  | 
|  | err = sasl_setprop(vs->sasl.conn, SASL_SEC_PROPS, &secprops); | 
|  | if (err != SASL_OK) { | 
|  | trace_vnc_auth_fail(vs, vs->auth, "cannot set SASL security props", | 
|  | sasl_errstring(err, NULL, NULL)); | 
|  | sasl_dispose(&vs->sasl.conn); | 
|  | vs->sasl.conn = NULL; | 
|  | goto authabort; | 
|  | } | 
|  |  | 
|  | err = sasl_listmech(vs->sasl.conn, | 
|  | NULL, /* Don't need to set user */ | 
|  | "", /* Prefix */ | 
|  | ",", /* Separator */ | 
|  | "", /* Suffix */ | 
|  | &mechlist, | 
|  | NULL, | 
|  | NULL); | 
|  | if (err != SASL_OK) { | 
|  | trace_vnc_auth_fail(vs, vs->auth, "cannot list SASL mechanisms", | 
|  | sasl_errdetail(vs->sasl.conn)); | 
|  | sasl_dispose(&vs->sasl.conn); | 
|  | vs->sasl.conn = NULL; | 
|  | goto authabort; | 
|  | } | 
|  | trace_vnc_auth_sasl_mech_list(vs, mechlist); | 
|  |  | 
|  | if (g_str_equal(mechlist, "")) { | 
|  | trace_vnc_auth_fail(vs, vs->auth, "no available SASL mechanisms", ""); | 
|  | sasl_dispose(&vs->sasl.conn); | 
|  | vs->sasl.conn = NULL; | 
|  | goto authabort; | 
|  | } | 
|  |  | 
|  | vs->sasl.mechlist = g_strdup(mechlist); | 
|  | mechlistlen = strlen(mechlist); | 
|  | vnc_write_u32(vs, mechlistlen); | 
|  | vnc_write(vs, mechlist, mechlistlen); | 
|  | vnc_flush(vs); | 
|  |  | 
|  | vnc_read_when(vs, protocol_client_auth_sasl_mechname_len, 4); | 
|  |  | 
|  | return; | 
|  |  | 
|  | authabort: | 
|  | error_free(local_err); | 
|  | vnc_client_error(vs); | 
|  | } | 
|  |  | 
|  |  |