curl/lib/krb5.c

903 строки
23 KiB
C

/* GSSAPI/krb5 support for FTP - loosely based on old krb4.c
*
* Copyright (c) 1995, 1996, 1997, 1998, 1999 Kungliga Tekniska Högskolan
* (Royal Institute of Technology, Stockholm, Sweden).
* Copyright (c) 2004 - 2022 Daniel Stenberg
* All rights reserved.
*
* SPDX-License-Identifier: BSD-3-Clause
*
* 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
#ifdef HAVE_ARPA_INET_H
#include <arpa/inet.h>
#endif
#include "urldata.h"
#include "curl_base64.h"
#include "ftp.h"
#include "curl_gssapi.h"
#include "sendf.h"
#include "curl_krb5.h"
#include "warnless.h"
#include "strcase.h"
#include "strdup.h"
/* The last 3 #include files should be in this order */
#include "curl_printf.h"
#include "curl_memory.h"
#include "memdebug.h"
static CURLcode ftpsend(struct Curl_easy *data, struct connectdata *conn,
const char *cmd)
{
ssize_t bytes_written;
#define SBUF_SIZE 1024
char s[SBUF_SIZE];
size_t write_len;
char *sptr = s;
CURLcode result = CURLE_OK;
#ifdef HAVE_GSSAPI
enum protection_level data_sec = conn->data_prot;
#endif
if(!cmd)
return CURLE_BAD_FUNCTION_ARGUMENT;
write_len = strlen(cmd);
if(!write_len || write_len > (sizeof(s) -3))
return CURLE_BAD_FUNCTION_ARGUMENT;
memcpy(&s, cmd, write_len);
strcpy(&s[write_len], "\r\n"); /* append a trailing CRLF */
write_len += 2;
bytes_written = 0;
for(;;) {
#ifdef HAVE_GSSAPI
conn->data_prot = PROT_CMD;
#endif
result = Curl_write(data, conn->sock[FIRSTSOCKET], sptr, write_len,
&bytes_written);
#ifdef HAVE_GSSAPI
DEBUGASSERT(data_sec > PROT_NONE && data_sec < PROT_LAST);
conn->data_prot = data_sec;
#endif
if(result)
break;
Curl_debug(data, CURLINFO_HEADER_OUT, sptr, (size_t)bytes_written);
if(bytes_written != (ssize_t)write_len) {
write_len -= bytes_written;
sptr += bytes_written;
}
else
break;
}
return result;
}
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_unwrap(&min, *context, &enc, &dec, NULL, NULL);
if(maj != GSS_S_COMPLETE)
return -1;
memcpy(buf, dec.value, dec.length);
len = curlx_uztosi(dec.length);
gss_release_buffer(&min, &dec);
return len;
}
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_wrap()
*/
dec.value = (void *)from;
dec.length = length;
maj = gss_wrap(&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 Curl_easy *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);
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;
char *stringp;
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 = ftpsend(data, conn, "AUTH GSSAPI");
if(result)
return -2;
if(Curl_GetFTPResponse(data, &nread, NULL))
return -1;
if(data->state.buffer[0] != '3')
return -1;
}
stringp = aprintf("%s@%s", service, host);
if(!stringp)
return -2;
input_buffer.value = stringp;
input_buffer.length = strlen(stringp);
maj = gss_import_name(&min, &input_buffer, GSS_C_NT_HOSTBASED_SERVICE,
&gssname);
free(stringp);
if(maj != GSS_S_COMPLETE) {
gss_release_name(&min, &gssname);
if(service == srv_host) {
failf(data, "Error importing service name %s@%s", service, host);
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);
infof(data, "Trying against %s", 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)) {
infof(data, "Error creating security context");
ret = AUTH_ERROR;
break;
}
if(output_buffer.length) {
char *cmd;
result = Curl_base64_encode((char *)output_buffer.value,
output_buffer.length, &p, &base64_sz);
if(result) {
infof(data, "base64-encoding: %s", curl_easy_strerror(result));
ret = AUTH_ERROR;
break;
}
cmd = aprintf("ADAT %s", p);
if(cmd)
result = ftpsend(data, conn, cmd);
else
result = CURLE_OUT_OF_MEMORY;
free(p);
free(cmd);
if(result) {
ret = -2;
break;
}
if(Curl_GetFTPResponse(data, &nread, NULL)) {
ret = -1;
break;
}
if(data->state.buffer[0] != '2' && data->state.buffer[0] != '3') {
infof(data, "Server didn't accept auth data");
ret = AUTH_ERROR;
break;
}
_gssresp.value = NULL; /* make sure it is initialized */
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) {
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) {
OM_uint32 maj = gss_delete_sec_context(&min, context, GSS_C_NO_BUFFER);
(void)maj;
DEBUGASSERT(maj == GSS_S_COMPLETE);
}
}
static const 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_encode,
krb5_decode
};
static const struct {
enum protection_level level;
const char *name;
} level_names[] = {
{ PROT_CLEAR, "clear" },
{ PROT_SAFE, "safe" },
{ PROT_CONFIDENTIAL, "confidential" },
{ PROT_PRIVATE, "private" }
};
static enum protection_level
name_to_level(const char *name)
{
int i;
for(i = 0; i < (int)sizeof(level_names)/(int)sizeof(level_names[0]); i++)
if(curl_strequal(name, level_names[i].name))
return level_names[i].level;
return PROT_NONE;
}
/* Convert a protocol |level| to its char representation.
We take an int to catch programming mistakes. */
static char level_to_char(int level)
{
switch(level) {
case PROT_CLEAR:
return 'C';
case PROT_SAFE:
return 'S';
case PROT_CONFIDENTIAL:
return 'E';
case PROT_PRIVATE:
return 'P';
case PROT_CMD:
/* Fall through */
default:
/* Those 2 cases should not be reached! */
break;
}
DEBUGASSERT(0);
/* Default to the most secure alternative. */
return 'P';
}
/* Send an FTP command defined by |message| and the optional arguments. The
function returns the ftp_code. If an error occurs, -1 is returned. */
static int ftp_send_command(struct Curl_easy *data, const char *message, ...)
{
int ftp_code;
ssize_t nread = 0;
va_list args;
char print_buffer[50];
va_start(args, message);
mvsnprintf(print_buffer, sizeof(print_buffer), message, args);
va_end(args);
if(ftpsend(data, data->conn, print_buffer)) {
ftp_code = -1;
}
else {
if(Curl_GetFTPResponse(data, &nread, &ftp_code))
ftp_code = -1;
}
(void)nread; /* Unused */
return ftp_code;
}
/* Read |len| from the socket |fd| and store it in |to|. Return a CURLcode
saying whether an error occurred or CURLE_OK if |len| was read. */
static CURLcode
socket_read(curl_socket_t fd, void *to, size_t len)
{
char *to_p = to;
CURLcode result;
ssize_t nread = 0;
while(len > 0) {
result = Curl_read_plain(fd, to_p, len, &nread);
if(!result) {
len -= nread;
to_p += nread;
}
else {
if(result == CURLE_AGAIN)
continue;
return result;
}
}
return CURLE_OK;
}
/* Write |len| bytes from the buffer |to| to the socket |fd|. Return a
CURLcode saying whether an error occurred or CURLE_OK if |len| was
written. */
static CURLcode
socket_write(struct Curl_easy *data, curl_socket_t fd, const void *to,
size_t len)
{
const char *to_p = to;
CURLcode result;
ssize_t written;
while(len > 0) {
result = Curl_write_plain(data, fd, to_p, len, &written);
if(!result) {
len -= written;
to_p += written;
}
else {
if(result == CURLE_AGAIN)
continue;
return result;
}
}
return CURLE_OK;
}
static CURLcode read_data(struct connectdata *conn,
curl_socket_t fd,
struct krb5buffer *buf)
{
int len;
CURLcode result;
int nread;
result = socket_read(fd, &len, sizeof(len));
if(result)
return result;
if(len) {
/* only realloc if there was a length */
len = ntohl(len);
if(len > CURL_MAX_INPUT_LENGTH)
len = 0;
else
buf->data = Curl_saferealloc(buf->data, len);
}
if(!len || !buf->data)
return CURLE_OUT_OF_MEMORY;
result = socket_read(fd, buf->data, len);
if(result)
return result;
nread = conn->mech->decode(conn->app_data, buf->data, len,
conn->data_prot, conn);
if(nread < 0)
return CURLE_RECV_ERROR;
buf->size = (size_t)nread;
buf->index = 0;
return CURLE_OK;
}
static size_t
buffer_read(struct krb5buffer *buf, void *data, size_t len)
{
if(buf->size - buf->index < len)
len = buf->size - buf->index;
memcpy(data, (char *)buf->data + buf->index, len);
buf->index += len;
return len;
}
/* Matches Curl_recv signature */
static ssize_t sec_recv(struct Curl_easy *data, int sockindex,
char *buffer, size_t len, CURLcode *err)
{
size_t bytes_read;
size_t total_read = 0;
struct connectdata *conn = data->conn;
curl_socket_t fd = conn->sock[sockindex];
*err = CURLE_OK;
/* Handle clear text response. */
if(conn->sec_complete == 0 || conn->data_prot == PROT_CLEAR)
return sread(fd, buffer, len);
if(conn->in_buffer.eof_flag) {
conn->in_buffer.eof_flag = 0;
return 0;
}
bytes_read = buffer_read(&conn->in_buffer, buffer, len);
len -= bytes_read;
total_read += bytes_read;
buffer += bytes_read;
while(len > 0) {
if(read_data(conn, fd, &conn->in_buffer))
return -1;
if(conn->in_buffer.size == 0) {
if(bytes_read > 0)
conn->in_buffer.eof_flag = 1;
return bytes_read;
}
bytes_read = buffer_read(&conn->in_buffer, buffer, len);
len -= bytes_read;
total_read += bytes_read;
buffer += bytes_read;
}
return total_read;
}
/* Send |length| bytes from |from| to the |fd| socket taking care of encoding
and negotiating with the server. |from| can be NULL. */
static void do_sec_send(struct Curl_easy *data, struct connectdata *conn,
curl_socket_t fd, const char *from, int length)
{
int bytes, htonl_bytes; /* 32-bit integers for htonl */
char *buffer = NULL;
char *cmd_buffer;
size_t cmd_size = 0;
CURLcode error;
enum protection_level prot_level = conn->data_prot;
bool iscmd = (prot_level == PROT_CMD)?TRUE:FALSE;
DEBUGASSERT(prot_level > PROT_NONE && prot_level < PROT_LAST);
if(iscmd) {
if(!strncmp(from, "PASS ", 5) || !strncmp(from, "ACCT ", 5))
prot_level = PROT_PRIVATE;
else
prot_level = conn->command_prot;
}
bytes = conn->mech->encode(conn->app_data, from, length, prot_level,
(void **)&buffer);
if(!buffer || bytes <= 0)
return; /* error */
if(iscmd) {
error = Curl_base64_encode(buffer, curlx_sitouz(bytes),
&cmd_buffer, &cmd_size);
if(error) {
free(buffer);
return; /* error */
}
if(cmd_size > 0) {
static const char *enc = "ENC ";
static const char *mic = "MIC ";
if(prot_level == PROT_PRIVATE)
socket_write(data, fd, enc, 4);
else
socket_write(data, fd, mic, 4);
socket_write(data, fd, cmd_buffer, cmd_size);
socket_write(data, fd, "\r\n", 2);
infof(data, "Send: %s%s", prot_level == PROT_PRIVATE?enc:mic,
cmd_buffer);
free(cmd_buffer);
}
}
else {
htonl_bytes = htonl(bytes);
socket_write(data, fd, &htonl_bytes, sizeof(htonl_bytes));
socket_write(data, fd, buffer, curlx_sitouz(bytes));
}
free(buffer);
}
static ssize_t sec_write(struct Curl_easy *data, struct connectdata *conn,
curl_socket_t fd, const char *buffer, size_t length)
{
ssize_t tx = 0, len = conn->buffer_size;
if(len <= 0)
len = length;
while(length) {
if(length < (size_t)len)
len = length;
do_sec_send(data, conn, fd, buffer, curlx_sztosi(len));
length -= len;
buffer += len;
tx += len;
}
return tx;
}
/* Matches Curl_send signature */
static ssize_t sec_send(struct Curl_easy *data, int sockindex,
const void *buffer, size_t len, CURLcode *err)
{
struct connectdata *conn = data->conn;
curl_socket_t fd = conn->sock[sockindex];
*err = CURLE_OK;
return sec_write(data, conn, fd, buffer, len);
}
int Curl_sec_read_msg(struct Curl_easy *data, struct connectdata *conn,
char *buffer, enum protection_level level)
{
/* decoded_len should be size_t or ssize_t but conn->mech->decode returns an
int */
int decoded_len;
char *buf;
int ret_code = 0;
size_t decoded_sz = 0;
CURLcode error;
(void) data;
if(!conn->mech)
/* not initialized, return error */
return -1;
DEBUGASSERT(level > PROT_NONE && level < PROT_LAST);
error = Curl_base64_decode(buffer + 4, (unsigned char **)&buf, &decoded_sz);
if(error || decoded_sz == 0)
return -1;
if(decoded_sz > (size_t)INT_MAX) {
free(buf);
return -1;
}
decoded_len = curlx_uztosi(decoded_sz);
decoded_len = conn->mech->decode(conn->app_data, buf, decoded_len,
level, conn);
if(decoded_len <= 0) {
free(buf);
return -1;
}
{
buf[decoded_len] = '\n';
Curl_debug(data, CURLINFO_HEADER_IN, buf, decoded_len + 1);
}
buf[decoded_len] = '\0';
if(decoded_len <= 3)
/* suspiciously short */
return 0;
if(buf[3] != '-')
/* safe to ignore return code */
(void)sscanf(buf, "%d", &ret_code);
if(buf[decoded_len - 1] == '\n')
buf[decoded_len - 1] = '\0';
strcpy(buffer, buf);
free(buf);
return ret_code;
}
static int sec_set_protection_level(struct Curl_easy *data)
{
int code;
struct connectdata *conn = data->conn;
enum protection_level level = conn->request_data_prot;
DEBUGASSERT(level > PROT_NONE && level < PROT_LAST);
if(!conn->sec_complete) {
infof(data, "Trying to change the protection level after the"
" completion of the data exchange.");
return -1;
}
/* Bail out if we try to set up the same level */
if(conn->data_prot == level)
return 0;
if(level) {
char *pbsz;
unsigned int buffer_size = 1 << 20; /* 1048576 */
code = ftp_send_command(data, "PBSZ %u", buffer_size);
if(code < 0)
return -1;
if(code/100 != 2) {
failf(data, "Failed to set the protection's buffer size.");
return -1;
}
conn->buffer_size = buffer_size;
pbsz = strstr(data->state.buffer, "PBSZ=");
if(pbsz) {
/* ignore return code, use default value if it fails */
(void)sscanf(pbsz, "PBSZ=%u", &buffer_size);
if(buffer_size < conn->buffer_size)
conn->buffer_size = buffer_size;
}
}
/* Now try to negotiate the protection level. */
code = ftp_send_command(data, "PROT %c", level_to_char(level));
if(code < 0)
return -1;
if(code/100 != 2) {
failf(data, "Failed to set the protection level.");
return -1;
}
conn->data_prot = level;
if(level == PROT_PRIVATE)
conn->command_prot = level;
return 0;
}
int
Curl_sec_request_prot(struct connectdata *conn, const char *level)
{
enum protection_level l = name_to_level(level);
if(l == PROT_NONE)
return -1;
DEBUGASSERT(l > PROT_NONE && l < PROT_LAST);
conn->request_data_prot = l;
return 0;
}
static CURLcode choose_mech(struct Curl_easy *data, struct connectdata *conn)
{
int ret;
void *tmp_allocation;
const struct Curl_sec_client_mech *mech = &Curl_krb5_client_mech;
tmp_allocation = realloc(conn->app_data, mech->size);
if(!tmp_allocation) {
failf(data, "Failed realloc of size %zu", mech->size);
mech = NULL;
return CURLE_OUT_OF_MEMORY;
}
conn->app_data = tmp_allocation;
if(mech->init) {
ret = mech->init(conn->app_data);
if(ret) {
infof(data, "Failed initialization for %s. Skipping it.",
mech->name);
return CURLE_FAILED_INIT;
}
}
infof(data, "Trying mechanism %s...", mech->name);
ret = ftp_send_command(data, "AUTH %s", mech->name);
if(ret < 0)
return CURLE_COULDNT_CONNECT;
if(ret/100 != 3) {
switch(ret) {
case 504:
infof(data, "Mechanism %s is not supported by the server (server "
"returned ftp code: 504).", mech->name);
break;
case 534:
infof(data, "Mechanism %s was rejected by the server (server returned "
"ftp code: 534).", mech->name);
break;
default:
if(ret/100 == 5) {
infof(data, "server does not support the security extensions");
return CURLE_USE_SSL_FAILED;
}
break;
}
return CURLE_LOGIN_DENIED;
}
/* Authenticate */
ret = mech->auth(conn->app_data, data, conn);
if(ret != AUTH_CONTINUE) {
if(ret != AUTH_OK) {
/* Mechanism has dumped the error to stderr, don't error here. */
return CURLE_USE_SSL_FAILED;
}
DEBUGASSERT(ret == AUTH_OK);
conn->mech = mech;
conn->sec_complete = 1;
conn->recv[FIRSTSOCKET] = sec_recv;
conn->send[FIRSTSOCKET] = sec_send;
conn->recv[SECONDARYSOCKET] = sec_recv;
conn->send[SECONDARYSOCKET] = sec_send;
conn->command_prot = PROT_SAFE;
/* Set the requested protection level */
/* BLOCKING */
(void)sec_set_protection_level(data);
}
return CURLE_OK;
}
CURLcode
Curl_sec_login(struct Curl_easy *data, struct connectdata *conn)
{
return choose_mech(data, conn);
}
void
Curl_sec_end(struct connectdata *conn)
{
if(conn->mech && conn->mech->end)
conn->mech->end(conn->app_data);
free(conn->app_data);
conn->app_data = NULL;
if(conn->in_buffer.data) {
free(conn->in_buffer.data);
conn->in_buffer.data = NULL;
conn->in_buffer.size = 0;
conn->in_buffer.index = 0;
conn->in_buffer.eof_flag = 0;
}
conn->sec_complete = 0;
conn->data_prot = PROT_CLEAR;
conn->mech = NULL;
}
#endif /* HAVE_GSSAPI && !CURL_DISABLE_FTP */