[164] | 1 | /* GSSAPI/krb5 support for FTP - loosely based on old krb4.c
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| 2 | *
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| 3 | * Copyright (c) 1995, 1996, 1997, 1998, 1999 Kungliga Tekniska Högskolan
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| 4 | * (Royal Institute of Technology, Stockholm, Sweden).
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| 5 | * Copyright (c) 2004 - 2015 Daniel Stenberg
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| 6 | * All rights reserved.
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| 7 | *
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| 8 | * Redistribution and use in source and binary forms, with or without
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| 9 | * modification, are permitted provided that the following conditions
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| 10 | * are met:
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| 11 | *
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| 12 | * 1. Redistributions of source code must retain the above copyright
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| 13 | * notice, this list of conditions and the following disclaimer.
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| 14 | *
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| 15 | * 2. Redistributions in binary form must reproduce the above copyright
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| 16 | * notice, this list of conditions and the following disclaimer in the
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| 17 | * documentation and/or other materials provided with the distribution.
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| 18 | *
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| 19 | * 3. Neither the name of the Institute nor the names of its contributors
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| 20 | * may be used to endorse or promote products derived from this software
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| 21 | * without specific prior written permission.
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| 22 | *
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| 23 | * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
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| 24 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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| 25 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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| 26 | * ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
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| 27 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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| 28 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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| 29 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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| 30 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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| 31 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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| 32 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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| 33 | * SUCH DAMAGE. */
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| 34 |
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| 35 | #include "curl_setup.h"
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| 36 |
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| 37 | #if defined(HAVE_GSSAPI) && !defined(CURL_DISABLE_FTP)
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| 38 |
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| 39 | #ifdef HAVE_NETDB_H
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| 40 | #include <netdb.h>
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| 41 | #endif
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| 42 |
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| 43 | #include "urldata.h"
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| 44 | #include "curl_base64.h"
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| 45 | #include "ftp.h"
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| 46 | #include "curl_gssapi.h"
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| 47 | #include "sendf.h"
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| 48 | #include "curl_sec.h"
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| 49 | #include "warnless.h"
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| 50 | #include "curl_printf.h"
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| 51 |
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| 52 | /* The last #include files should be: */
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| 53 | #include "curl_memory.h"
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| 54 | #include "memdebug.h"
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| 55 |
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| 56 | #define LOCAL_ADDR (&conn->local_addr)
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| 57 | #define REMOTE_ADDR conn->ip_addr->ai_addr
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| 58 |
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| 59 | static int
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| 60 | krb5_init(void *app_data)
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| 61 | {
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| 62 | gss_ctx_id_t *context = app_data;
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| 63 | /* Make sure our context is initialized for krb5_end. */
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| 64 | *context = GSS_C_NO_CONTEXT;
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| 65 | return 0;
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| 66 | }
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| 67 |
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| 68 | static int
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| 69 | krb5_check_prot(void *app_data, int level)
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| 70 | {
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| 71 | (void)app_data; /* unused */
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| 72 | if(level == PROT_CONFIDENTIAL)
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| 73 | return -1;
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| 74 | return 0;
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| 75 | }
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| 76 |
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| 77 | static int
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| 78 | krb5_decode(void *app_data, void *buf, int len,
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| 79 | int level UNUSED_PARAM,
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| 80 | struct connectdata *conn UNUSED_PARAM)
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| 81 | {
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| 82 | gss_ctx_id_t *context = app_data;
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| 83 | OM_uint32 maj, min;
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| 84 | gss_buffer_desc enc, dec;
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| 85 |
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| 86 | (void)level;
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| 87 | (void)conn;
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| 88 |
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| 89 | enc.value = buf;
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| 90 | enc.length = len;
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| 91 | maj = gss_unseal(&min, *context, &enc, &dec, NULL, NULL);
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| 92 | if(maj != GSS_S_COMPLETE) {
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| 93 | if(len >= 4)
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| 94 | strcpy(buf, "599 ");
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| 95 | return -1;
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| 96 | }
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| 97 |
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| 98 | memcpy(buf, dec.value, dec.length);
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| 99 | len = curlx_uztosi(dec.length);
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| 100 | gss_release_buffer(&min, &dec);
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| 101 |
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| 102 | return len;
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| 103 | }
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| 104 |
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| 105 | static int
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| 106 | krb5_overhead(void *app_data, int level, int len)
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| 107 | {
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| 108 | /* no arguments are used */
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| 109 | (void)app_data;
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| 110 | (void)level;
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| 111 | (void)len;
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| 112 | return 0;
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| 113 | }
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| 114 |
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| 115 | static int
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| 116 | krb5_encode(void *app_data, const void *from, int length, int level, void **to)
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| 117 | {
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| 118 | gss_ctx_id_t *context = app_data;
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| 119 | gss_buffer_desc dec, enc;
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| 120 | OM_uint32 maj, min;
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| 121 | int state;
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| 122 | int len;
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| 123 |
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| 124 | /* NOTE that the cast is safe, neither of the krb5, gnu gss and heimdal
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| 125 | * libraries modify the input buffer in gss_seal()
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| 126 | */
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| 127 | dec.value = (void*)from;
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| 128 | dec.length = length;
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| 129 | maj = gss_seal(&min, *context,
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| 130 | level == PROT_PRIVATE,
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| 131 | GSS_C_QOP_DEFAULT,
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| 132 | &dec, &state, &enc);
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| 133 |
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| 134 | if(maj != GSS_S_COMPLETE)
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| 135 | return -1;
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| 136 |
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| 137 | /* malloc a new buffer, in case gss_release_buffer doesn't work as
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| 138 | expected */
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| 139 | *to = malloc(enc.length);
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| 140 | if(!*to)
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| 141 | return -1;
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| 142 | memcpy(*to, enc.value, enc.length);
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| 143 | len = curlx_uztosi(enc.length);
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| 144 | gss_release_buffer(&min, &enc);
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| 145 | return len;
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| 146 | }
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| 147 |
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| 148 | static int
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| 149 | krb5_auth(void *app_data, struct connectdata *conn)
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| 150 | {
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| 151 | int ret = AUTH_OK;
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| 152 | char *p;
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| 153 | const char *host = conn->host.name;
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| 154 | ssize_t nread;
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| 155 | curl_socklen_t l = sizeof(conn->local_addr);
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| 156 | struct SessionHandle *data = conn->data;
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| 157 | CURLcode result;
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| 158 | const char *service = "ftp", *srv_host = "host";
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| 159 | gss_buffer_desc input_buffer, output_buffer, _gssresp, *gssresp;
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| 160 | OM_uint32 maj, min;
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| 161 | gss_name_t gssname;
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| 162 | gss_ctx_id_t *context = app_data;
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| 163 | struct gss_channel_bindings_struct chan;
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| 164 | size_t base64_sz = 0;
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| 165 |
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| 166 | if(getsockname(conn->sock[FIRSTSOCKET],
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| 167 | (struct sockaddr *)LOCAL_ADDR, &l) < 0)
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| 168 | perror("getsockname()");
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| 169 |
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| 170 | chan.initiator_addrtype = GSS_C_AF_INET;
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| 171 | chan.initiator_address.length = l - 4;
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| 172 | chan.initiator_address.value =
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| 173 | &((struct sockaddr_in *)LOCAL_ADDR)->sin_addr.s_addr;
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| 174 | chan.acceptor_addrtype = GSS_C_AF_INET;
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| 175 | chan.acceptor_address.length = l - 4;
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| 176 | chan.acceptor_address.value =
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| 177 | &((struct sockaddr_in *)REMOTE_ADDR)->sin_addr.s_addr;
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| 178 | chan.application_data.length = 0;
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| 179 | chan.application_data.value = NULL;
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| 180 |
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| 181 | /* this loop will execute twice (once for service, once for host) */
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| 182 | for(;;) {
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| 183 | /* this really shouldn't be repeated here, but can't help it */
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| 184 | if(service == srv_host) {
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| 185 | result = Curl_ftpsendf(conn, "AUTH GSSAPI");
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| 186 |
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| 187 | if(result)
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| 188 | return -2;
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| 189 | if(Curl_GetFTPResponse(&nread, conn, NULL))
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| 190 | return -1;
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| 191 |
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| 192 | if(data->state.buffer[0] != '3')
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| 193 | return -1;
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| 194 | }
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| 195 |
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| 196 | input_buffer.value = data->state.buffer;
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| 197 | input_buffer.length = snprintf(input_buffer.value, BUFSIZE, "%s@%s",
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| 198 | service, host);
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| 199 | maj = gss_import_name(&min, &input_buffer, GSS_C_NT_HOSTBASED_SERVICE,
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| 200 | &gssname);
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| 201 | if(maj != GSS_S_COMPLETE) {
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| 202 | gss_release_name(&min, &gssname);
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| 203 | if(service == srv_host) {
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| 204 | Curl_failf(data, "Error importing service name %s",
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| 205 | input_buffer.value);
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| 206 | return AUTH_ERROR;
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| 207 | }
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| 208 | service = srv_host;
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| 209 | continue;
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| 210 | }
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| 211 | /* We pass NULL as |output_name_type| to avoid a leak. */
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| 212 | gss_display_name(&min, gssname, &output_buffer, NULL);
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| 213 | Curl_infof(data, "Trying against %s\n", output_buffer.value);
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| 214 | gssresp = GSS_C_NO_BUFFER;
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| 215 | *context = GSS_C_NO_CONTEXT;
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| 216 |
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| 217 | do {
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| 218 | /* Release the buffer at each iteration to avoid leaking: the first time
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| 219 | we are releasing the memory from gss_display_name. The last item is
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| 220 | taken care by a final gss_release_buffer. */
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| 221 | gss_release_buffer(&min, &output_buffer);
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| 222 | ret = AUTH_OK;
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| 223 | maj = Curl_gss_init_sec_context(data,
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| 224 | &min,
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| 225 | context,
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| 226 | gssname,
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| 227 | &Curl_krb5_mech_oid,
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| 228 | &chan,
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| 229 | gssresp,
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| 230 | &output_buffer,
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| 231 | TRUE,
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| 232 | NULL);
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| 233 |
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| 234 | if(gssresp) {
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| 235 | free(_gssresp.value);
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| 236 | gssresp = NULL;
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| 237 | }
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| 238 |
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| 239 | if(GSS_ERROR(maj)) {
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| 240 | Curl_infof(data, "Error creating security context\n");
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| 241 | ret = AUTH_ERROR;
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| 242 | break;
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| 243 | }
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| 244 |
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| 245 | if(output_buffer.length != 0) {
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| 246 | result = Curl_base64_encode(data, (char *)output_buffer.value,
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| 247 | output_buffer.length, &p, &base64_sz);
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| 248 | if(result) {
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| 249 | Curl_infof(data, "base64-encoding: %s\n",
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| 250 | curl_easy_strerror(result));
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| 251 | ret = AUTH_CONTINUE;
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| 252 | break;
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| 253 | }
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| 254 |
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| 255 | result = Curl_ftpsendf(conn, "ADAT %s", p);
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| 256 |
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| 257 | free(p);
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| 258 |
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| 259 | if(result) {
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| 260 | ret = -2;
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| 261 | break;
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| 262 | }
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| 263 |
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| 264 | if(Curl_GetFTPResponse(&nread, conn, NULL)) {
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| 265 | ret = -1;
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| 266 | break;
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| 267 | }
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| 268 |
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| 269 | if(data->state.buffer[0] != '2' && data->state.buffer[0] != '3') {
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| 270 | Curl_infof(data, "Server didn't accept auth data\n");
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| 271 | ret = AUTH_ERROR;
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| 272 | break;
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| 273 | }
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| 274 |
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| 275 | p = data->state.buffer + 4;
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| 276 | p = strstr(p, "ADAT=");
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| 277 | if(p) {
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| 278 | result = Curl_base64_decode(p + 5,
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| 279 | (unsigned char **)&_gssresp.value,
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| 280 | &_gssresp.length);
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| 281 | if(result) {
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| 282 | Curl_failf(data, "base64-decoding: %s",
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| 283 | curl_easy_strerror(result));
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| 284 | ret = AUTH_CONTINUE;
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| 285 | break;
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| 286 | }
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| 287 | }
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| 288 |
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| 289 | gssresp = &_gssresp;
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| 290 | }
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| 291 | } while(maj == GSS_S_CONTINUE_NEEDED);
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| 292 |
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| 293 | gss_release_name(&min, &gssname);
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| 294 | gss_release_buffer(&min, &output_buffer);
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| 295 |
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| 296 | if(gssresp)
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| 297 | free(_gssresp.value);
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| 298 |
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| 299 | if(ret == AUTH_OK || service == srv_host)
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| 300 | return ret;
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| 301 |
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| 302 | service = srv_host;
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| 303 | }
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| 304 | return ret;
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| 305 | }
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| 306 |
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| 307 | static void krb5_end(void *app_data)
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| 308 | {
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| 309 | OM_uint32 min;
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| 310 | gss_ctx_id_t *context = app_data;
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| 311 | if(*context != GSS_C_NO_CONTEXT) {
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| 312 | #ifdef DEBUGBUILD
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| 313 | OM_uint32 maj =
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| 314 | #endif
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| 315 | gss_delete_sec_context(&min, context, GSS_C_NO_BUFFER);
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| 316 | DEBUGASSERT(maj == GSS_S_COMPLETE);
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| 317 | }
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| 318 | }
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| 319 |
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| 320 | struct Curl_sec_client_mech Curl_krb5_client_mech = {
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| 321 | "GSSAPI",
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| 322 | sizeof(gss_ctx_id_t),
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| 323 | krb5_init,
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| 324 | krb5_auth,
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| 325 | krb5_end,
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| 326 | krb5_check_prot,
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| 327 | krb5_overhead,
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| 328 | krb5_encode,
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| 329 | krb5_decode
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| 330 | };
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| 331 |
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| 332 | #endif /* HAVE_GSSAPI && !CURL_DISABLE_FTP */
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