/* GSSAPI/krb5 support for FTP - loosely based on old krb4.c * * Copyright (c) 1995, 1996, 1997, 1998, 1999 Kungliga Tekniska H�gskolan * (Royal Institute of Technology, Stockholm, Sweden). * Copyright (c) 2004 - 2016 Daniel Stenberg * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * 3. Neither the name of the Institute nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ #include "curl_setup.h" #if defined(HAVE_GSSAPI) && !defined(CURL_DISABLE_FTP) #ifdef HAVE_NETDB_H #include <netdb.h> #endif #include "urldata.h" #include "curl_base64.h" #include "ftp.h" #include "curl_gssapi.h" #include "sendf.h" #include "curl_sec.h" #include "warnless.h" /* The last 3 #include files should be in this order */ #include "curl_printf.h" #include "curl_memory.h" #include "memdebug.h" static int krb5_init(void *app_data) { gss_ctx_id_t *context = app_data; /* Make sure our context is initialized for krb5_end. */ *context = GSS_C_NO_CONTEXT; return 0; } static int krb5_check_prot(void *app_data, int level) { (void)app_data; /* unused */ if(level == PROT_CONFIDENTIAL) return -1; return 0; } static int krb5_decode(void *app_data, void *buf, int len, int level UNUSED_PARAM, struct connectdata *conn UNUSED_PARAM) { gss_ctx_id_t *context = app_data; OM_uint32 maj, min; gss_buffer_desc enc, dec; (void)level; (void)conn; enc.value = buf; enc.length = len; maj = gss_unseal(&min, *context, &enc, &dec, NULL, NULL); if(maj != GSS_S_COMPLETE) { if(len >= 4) strcpy(buf, "599 "); return -1; } memcpy(buf, dec.value, dec.length); len = curlx_uztosi(dec.length); gss_release_buffer(&min, &dec); return len; } static int krb5_overhead(void *app_data, int level, int len) { /* no arguments are used */ (void)app_data; (void)level; (void)len; return 0; } static int krb5_encode(void *app_data, const void *from, int length, int level, void **to) { gss_ctx_id_t *context = app_data; gss_buffer_desc dec, enc; OM_uint32 maj, min; int state; int len; /* NOTE that the cast is safe, neither of the krb5, gnu gss and heimdal * libraries modify the input buffer in gss_seal() */ dec.value = (void*)from; dec.length = length; maj = gss_seal(&min, *context, level == PROT_PRIVATE, GSS_C_QOP_DEFAULT, &dec, &state, &enc); if(maj != GSS_S_COMPLETE) return -1; /* malloc a new buffer, in case gss_release_buffer doesn't work as expected */ *to = malloc(enc.length); if(!*to) return -1; memcpy(*to, enc.value, enc.length); len = curlx_uztosi(enc.length); gss_release_buffer(&min, &enc); return len; } static int krb5_auth(void *app_data, struct connectdata *conn) { int ret = AUTH_OK; char *p; const char *host = conn->host.name; ssize_t nread; curl_socklen_t l = sizeof(conn->local_addr); struct Curl_easy *data = conn->data; CURLcode result; const char *service = data->set.str[STRING_SERVICE_NAME] ? data->set.str[STRING_SERVICE_NAME] : "ftp"; const char *srv_host = "host"; gss_buffer_desc input_buffer, output_buffer, _gssresp, *gssresp; OM_uint32 maj, min; gss_name_t gssname; gss_ctx_id_t *context = app_data; struct gss_channel_bindings_struct chan; size_t base64_sz = 0; struct sockaddr_in **remote_addr = (struct sockaddr_in **)&conn->ip_addr->ai_addr; if(getsockname(conn->sock[FIRSTSOCKET], (struct sockaddr *)&conn->local_addr, &l) < 0) perror("getsockname()"); chan.initiator_addrtype = GSS_C_AF_INET; chan.initiator_address.length = l - 4; chan.initiator_address.value = &conn->local_addr.sin_addr.s_addr; chan.acceptor_addrtype = GSS_C_AF_INET; chan.acceptor_address.length = l - 4; chan.acceptor_address.value = &(*remote_addr)->sin_addr.s_addr; chan.application_data.length = 0; chan.application_data.value = NULL; /* this loop will execute twice (once for service, once for host) */ for(;;) { /* this really shouldn't be repeated here, but can't help it */ if(service == srv_host) { result = Curl_ftpsendf(conn, "AUTH GSSAPI"); if(result) return -2; if(Curl_GetFTPResponse(&nread, conn, NULL)) return -1; if(data->state.buffer[0] != '3') return -1; } input_buffer.value = data->state.buffer; input_buffer.length = snprintf(input_buffer.value, BUFSIZE, "%s@%s", service, host); maj = gss_import_name(&min, &input_buffer, GSS_C_NT_HOSTBASED_SERVICE, &gssname); if(maj != GSS_S_COMPLETE) { gss_release_name(&min, &gssname); if(service == srv_host) { Curl_failf(data, "Error importing service name %s", input_buffer.value); return AUTH_ERROR; } service = srv_host; continue; } /* We pass NULL as |output_name_type| to avoid a leak. */ gss_display_name(&min, gssname, &output_buffer, NULL); Curl_infof(data, "Trying against %s\n", output_buffer.value); gssresp = GSS_C_NO_BUFFER; *context = GSS_C_NO_CONTEXT; do { /* Release the buffer at each iteration to avoid leaking: the first time we are releasing the memory from gss_display_name. The last item is taken care by a final gss_release_buffer. */ gss_release_buffer(&min, &output_buffer); ret = AUTH_OK; maj = Curl_gss_init_sec_context(data, &min, context, gssname, &Curl_krb5_mech_oid, &chan, gssresp, &output_buffer, TRUE, NULL); if(gssresp) { free(_gssresp.value); gssresp = NULL; } if(GSS_ERROR(maj)) { Curl_infof(data, "Error creating security context\n"); ret = AUTH_ERROR; break; } if(output_buffer.length != 0) { result = Curl_base64_encode(data, (char *)output_buffer.value, output_buffer.length, &p, &base64_sz); if(result) { Curl_infof(data, "base64-encoding: %s\n", curl_easy_strerror(result)); ret = AUTH_CONTINUE; break; } result = Curl_ftpsendf(conn, "ADAT %s", p); free(p); if(result) { ret = -2; break; } if(Curl_GetFTPResponse(&nread, conn, NULL)) { ret = -1; break; } if(data->state.buffer[0] != '2' && data->state.buffer[0] != '3') { Curl_infof(data, "Server didn't accept auth data\n"); ret = AUTH_ERROR; break; } p = data->state.buffer + 4; p = strstr(p, "ADAT="); if(p) { result = Curl_base64_decode(p + 5, (unsigned char **)&_gssresp.value, &_gssresp.length); if(result) { Curl_failf(data, "base64-decoding: %s", curl_easy_strerror(result)); ret = AUTH_CONTINUE; break; } } gssresp = &_gssresp; } } while(maj == GSS_S_CONTINUE_NEEDED); gss_release_name(&min, &gssname); gss_release_buffer(&min, &output_buffer); if(gssresp) free(_gssresp.value); if(ret == AUTH_OK || service == srv_host) return ret; service = srv_host; } return ret; } static void krb5_end(void *app_data) { OM_uint32 min; gss_ctx_id_t *context = app_data; if(*context != GSS_C_NO_CONTEXT) { #ifdef DEBUGBUILD OM_uint32 maj = #endif gss_delete_sec_context(&min, context, GSS_C_NO_BUFFER); DEBUGASSERT(maj == GSS_S_COMPLETE); } } struct Curl_sec_client_mech Curl_krb5_client_mech = { "GSSAPI", sizeof(gss_ctx_id_t), krb5_init, krb5_auth, krb5_end, krb5_check_prot, krb5_overhead, krb5_encode, krb5_decode }; #endif /* HAVE_GSSAPI && !CURL_DISABLE_FTP */