344 lines
9.6 KiB
C
344 lines
9.6 KiB
C
/* GSSAPI/krb5 support for FTP - loosely based on old krb4.c
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*
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* Copyright (c) 1995, 1996, 1997, 1998, 1999 Kungliga Tekniska Högskolan
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* (Royal Institute of Technology, Stockholm, Sweden).
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* Copyright (c) 2004 - 2017 Daniel Stenberg
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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*
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* 3. Neither the name of the Institute nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE. */
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#include "curl_setup.h"
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#if defined(HAVE_GSSAPI) && !defined(CURL_DISABLE_FTP)
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#ifdef HAVE_NETDB_H
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#include <netdb.h>
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#endif
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#include "urldata.h"
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#include "curl_base64.h"
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#include "ftp.h"
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#include "curl_gssapi.h"
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#include "sendf.h"
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#include "curl_sec.h"
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#include "warnless.h"
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/* The last 3 #include files should be in this order */
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#include "curl_printf.h"
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#include "curl_memory.h"
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#include "memdebug.h"
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static int
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krb5_init(void *app_data)
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{
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gss_ctx_id_t *context = app_data;
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/* Make sure our context is initialized for krb5_end. */
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*context = GSS_C_NO_CONTEXT;
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return 0;
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}
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static int
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krb5_check_prot(void *app_data, int level)
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{
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(void)app_data; /* unused */
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if(level == PROT_CONFIDENTIAL)
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return -1;
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return 0;
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}
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static int
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krb5_decode(void *app_data, void *buf, int len,
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int level UNUSED_PARAM,
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struct connectdata *conn UNUSED_PARAM)
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{
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gss_ctx_id_t *context = app_data;
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OM_uint32 maj, min;
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gss_buffer_desc enc, dec;
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(void)level;
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(void)conn;
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enc.value = buf;
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enc.length = len;
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maj = gss_unwrap(&min, *context, &enc, &dec, NULL, NULL);
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if(maj != GSS_S_COMPLETE) {
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if(len >= 4)
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strcpy(buf, "599 ");
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return -1;
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}
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memcpy(buf, dec.value, dec.length);
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len = curlx_uztosi(dec.length);
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gss_release_buffer(&min, &dec);
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return len;
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}
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static int
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krb5_overhead(void *app_data, int level, int len)
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{
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/* no arguments are used */
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(void)app_data;
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(void)level;
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(void)len;
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return 0;
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}
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static int
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krb5_encode(void *app_data, const void *from, int length, int level, void **to)
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{
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gss_ctx_id_t *context = app_data;
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gss_buffer_desc dec, enc;
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OM_uint32 maj, min;
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int state;
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int len;
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/* NOTE that the cast is safe, neither of the krb5, gnu gss and heimdal
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* libraries modify the input buffer in gss_wrap()
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*/
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dec.value = (void *)from;
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dec.length = length;
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maj = gss_wrap(&min, *context,
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level == PROT_PRIVATE,
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GSS_C_QOP_DEFAULT,
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&dec, &state, &enc);
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if(maj != GSS_S_COMPLETE)
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return -1;
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/* malloc a new buffer, in case gss_release_buffer doesn't work as
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expected */
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*to = malloc(enc.length);
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if(!*to)
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return -1;
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memcpy(*to, enc.value, enc.length);
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len = curlx_uztosi(enc.length);
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gss_release_buffer(&min, &enc);
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return len;
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}
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static int
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krb5_auth(void *app_data, struct connectdata *conn)
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{
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int ret = AUTH_OK;
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char *p;
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const char *host = conn->host.name;
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ssize_t nread;
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curl_socklen_t l = sizeof(conn->local_addr);
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struct Curl_easy *data = conn->data;
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CURLcode result;
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const char *service = data->set.str[STRING_SERVICE_NAME] ?
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data->set.str[STRING_SERVICE_NAME] :
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"ftp";
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const char *srv_host = "host";
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gss_buffer_desc input_buffer, output_buffer, _gssresp, *gssresp;
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OM_uint32 maj, min;
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gss_name_t gssname;
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gss_ctx_id_t *context = app_data;
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struct gss_channel_bindings_struct chan;
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size_t base64_sz = 0;
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struct sockaddr_in **remote_addr =
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(struct sockaddr_in **)&conn->ip_addr->ai_addr;
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char *stringp;
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if(getsockname(conn->sock[FIRSTSOCKET],
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(struct sockaddr *)&conn->local_addr, &l) < 0)
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perror("getsockname()");
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chan.initiator_addrtype = GSS_C_AF_INET;
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chan.initiator_address.length = l - 4;
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chan.initiator_address.value = &conn->local_addr.sin_addr.s_addr;
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chan.acceptor_addrtype = GSS_C_AF_INET;
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chan.acceptor_address.length = l - 4;
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chan.acceptor_address.value = &(*remote_addr)->sin_addr.s_addr;
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chan.application_data.length = 0;
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chan.application_data.value = NULL;
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/* this loop will execute twice (once for service, once for host) */
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for(;;) {
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/* this really shouldn't be repeated here, but can't help it */
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if(service == srv_host) {
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result = Curl_ftpsend(conn, "AUTH GSSAPI");
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if(result)
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return -2;
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if(Curl_GetFTPResponse(&nread, conn, NULL))
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return -1;
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if(data->state.buffer[0] != '3')
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return -1;
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}
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stringp = aprintf("%s@%s", service, host);
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if(!stringp)
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return -2;
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input_buffer.value = stringp;
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input_buffer.length = strlen(stringp);
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maj = gss_import_name(&min, &input_buffer, GSS_C_NT_HOSTBASED_SERVICE,
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&gssname);
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free(stringp);
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if(maj != GSS_S_COMPLETE) {
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gss_release_name(&min, &gssname);
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if(service == srv_host) {
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failf(data, "Error importing service name %s@%s", service, host);
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return AUTH_ERROR;
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}
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service = srv_host;
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continue;
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}
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/* We pass NULL as |output_name_type| to avoid a leak. */
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gss_display_name(&min, gssname, &output_buffer, NULL);
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Curl_infof(data, "Trying against %s\n", output_buffer.value);
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gssresp = GSS_C_NO_BUFFER;
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*context = GSS_C_NO_CONTEXT;
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do {
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/* Release the buffer at each iteration to avoid leaking: the first time
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we are releasing the memory from gss_display_name. The last item is
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taken care by a final gss_release_buffer. */
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gss_release_buffer(&min, &output_buffer);
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ret = AUTH_OK;
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maj = Curl_gss_init_sec_context(data,
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&min,
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context,
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gssname,
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&Curl_krb5_mech_oid,
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&chan,
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gssresp,
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&output_buffer,
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TRUE,
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NULL);
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if(gssresp) {
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free(_gssresp.value);
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gssresp = NULL;
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}
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if(GSS_ERROR(maj)) {
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Curl_infof(data, "Error creating security context\n");
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ret = AUTH_ERROR;
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break;
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}
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if(output_buffer.length != 0) {
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char *cmd;
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result = Curl_base64_encode(data, (char *)output_buffer.value,
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output_buffer.length, &p, &base64_sz);
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if(result) {
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Curl_infof(data, "base64-encoding: %s\n",
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curl_easy_strerror(result));
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ret = AUTH_ERROR;
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break;
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}
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cmd = aprintf("ADAT %s", p);
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if(cmd)
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result = Curl_ftpsend(conn, cmd);
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else
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result = CURLE_OUT_OF_MEMORY;
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free(p);
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free(cmd);
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if(result) {
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ret = -2;
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break;
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}
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if(Curl_GetFTPResponse(&nread, conn, NULL)) {
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ret = -1;
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break;
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}
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if(data->state.buffer[0] != '2' && data->state.buffer[0] != '3') {
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Curl_infof(data, "Server didn't accept auth data\n");
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ret = AUTH_ERROR;
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break;
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}
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_gssresp.value = NULL; /* make sure it is initialized */
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p = data->state.buffer + 4;
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p = strstr(p, "ADAT=");
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if(p) {
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result = Curl_base64_decode(p + 5,
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(unsigned char **)&_gssresp.value,
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&_gssresp.length);
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if(result) {
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failf(data, "base64-decoding: %s", curl_easy_strerror(result));
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ret = AUTH_CONTINUE;
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break;
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}
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}
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gssresp = &_gssresp;
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}
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} while(maj == GSS_S_CONTINUE_NEEDED);
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gss_release_name(&min, &gssname);
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gss_release_buffer(&min, &output_buffer);
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if(gssresp)
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free(_gssresp.value);
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if(ret == AUTH_OK || service == srv_host)
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return ret;
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service = srv_host;
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}
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return ret;
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}
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static void krb5_end(void *app_data)
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{
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OM_uint32 min;
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gss_ctx_id_t *context = app_data;
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if(*context != GSS_C_NO_CONTEXT) {
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#ifdef DEBUGBUILD
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OM_uint32 maj =
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#endif
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gss_delete_sec_context(&min, context, GSS_C_NO_BUFFER);
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DEBUGASSERT(maj == GSS_S_COMPLETE);
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}
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}
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struct Curl_sec_client_mech Curl_krb5_client_mech = {
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"GSSAPI",
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sizeof(gss_ctx_id_t),
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krb5_init,
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krb5_auth,
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krb5_end,
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krb5_check_prot,
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krb5_overhead,
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krb5_encode,
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krb5_decode
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};
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#endif /* HAVE_GSSAPI && !CURL_DISABLE_FTP */
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