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/* This source code was modified by Martin Hedenfalk <mhe@stacken.kth.se> for
* use in Curl. His latest changes were done 2000-09-18.
*
* It has since been patched and modified a lot by Daniel Stenberg
* <daniel@haxx.se> to make it better applied to curl conditions, and to make
* it not use globals, pollute name space and more. This source code awaits a
* rewrite to work around the paragraph 2 in the BSD licenses as explained
* below.
*
* Copyright (c) 1998, 1999 Kungliga Tekniska Högskolan
* (Royal Institute of Technology, Stockholm, Sweden).
*
* Copyright (C) 2001 - 2015, Daniel Stenberg, <daniel@haxx.se>, et al.
*
* 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"
#ifndef CURL_DISABLE_FTP
#ifdef HAVE_GSSAPI
#ifdef HAVE_NETDB_H
#include <netdb.h>
#endif
#ifdef HAVE_LIMITS_H
#include <limits.h>
#endif
#include "urldata.h"
#include "curl_base64.h"
#include "curl_memory.h"
#include "curl_sec.h"
#include "ftp.h"
#include "sendf.h"
#include "rawstr.h"
#include "warnless.h"
/* The last #include file should be: */
#include "memdebug.h"
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(checkprefix(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 connectdata *conn, const char *message, ...)
{
int ftp_code;
ssize_t nread=0;
va_list args;
char print_buffer[50];
va_start(args, message);
vsnprintf(print_buffer, sizeof(print_buffer), message, args);
va_end(args);
if(Curl_ftpsendf(conn, print_buffer)) {
ftp_code = -1;
}
else {
if(Curl_GetFTPResponse(&nread, conn, &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;
while(len > 0) {
result = Curl_read_plain(fd, to_p, len, &nread);
if(!result) {
len -= nread;
to_p += nread;
}
else {
/* FIXME: We are doing a busy wait */
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 connectdata *conn, 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(conn, fd, to_p, len, &written);
if(!result) {
len -= written;
to_p += written;
}
else {
/* FIXME: We are doing a busy wait */
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;
void* tmp;
CURLcode result;
result = socket_read(fd, &len, sizeof(len));
if(result)
return result;
len = ntohl(len);
tmp = realloc(buf->data, len);
if(tmp == NULL)
return CURLE_OUT_OF_MEMORY;
buf->data = tmp;
result = socket_read(fd, buf->data, len);
if(result)
return result;
buf->size = conn->mech->decode(conn->app_data, buf->data, len,
conn->data_prot, conn);
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 connectdata *conn, int sockindex,
char *buffer, size_t len, CURLcode *err)
{
size_t bytes_read;
size_t total_read = 0;
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 read(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;
}
/* FIXME: Check for overflow */
return total_read;
}
/* Send |length| bytes from |from| to the |fd| socket taking care of encoding
and negociating with the server. |from| can be NULL. */
/* FIXME: We don't check for errors nor report any! */
static void do_sec_send(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(conn->data, 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(conn, fd, enc, 4);
else
socket_write(conn, fd, mic, 4);
socket_write(conn, fd, cmd_buffer, cmd_size);
socket_write(conn, fd, "\r\n", 2);
infof(conn->data, "Send: %s%s\n", prot_level == PROT_PRIVATE?enc:mic,
cmd_buffer);
free(cmd_buffer);
}
}
else {
htonl_bytes = htonl(bytes);
socket_write(conn, fd, &htonl_bytes, sizeof(htonl_bytes));
socket_write(conn, fd, buffer, curlx_sitouz(bytes));
}
free(buffer);
}
static ssize_t sec_write(struct connectdata *conn, curl_socket_t fd,
const char *buffer, size_t length)
{
ssize_t tx = 0, len = conn->buffer_size;
len -= conn->mech->overhead(conn->app_data, conn->data_prot,
curlx_sztosi(len));
if(len <= 0)
len = length;
while(length) {
if(length < (size_t)len)
len = length;
do_sec_send(conn, fd, buffer, curlx_sztosi(len));
length -= len;
buffer += len;
tx += len;
}
return tx;
}
/* Matches Curl_send signature */
static ssize_t sec_send(struct connectdata *conn, int sockindex,
const void *buffer, size_t len, CURLcode *err)
{
curl_socket_t fd = conn->sock[sockindex];
*err = CURLE_OK;
return sec_write(conn, fd, buffer, len);
}
int Curl_sec_read_msg(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;
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;
}
if(conn->data->set.verbose) {
buf[decoded_len] = '\n';
Curl_debug(conn->data, CURLINFO_HEADER_IN, buf, decoded_len + 1, conn);
}
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';
/* FIXME: Is |buffer| length always greater than |decoded_len|? */
strcpy(buffer, buf);
free(buf);
return ret_code;
}
/* FIXME: The error code returned here is never checked. */
static int sec_set_protection_level(struct connectdata *conn)
{
int code;
char* pbsz;
static unsigned int buffer_size = 1 << 20; /* 1048576 */
enum protection_level level = conn->request_data_prot;
DEBUGASSERT(level > PROT_NONE && level < PROT_LAST);
if(!conn->sec_complete) {
infof(conn->data, "Trying to change the protection level after the"
"completion of the data exchange.\n");
return -1;
}
/* Bail out if we try to set up the same level */
if(conn->data_prot == level)
return 0;
if(level) {
code = ftp_send_command(conn, "PBSZ %u", buffer_size);
if(code < 0)
return -1;
if(code/100 != 2) {
failf(conn->data, "Failed to set the protection's buffer size.");
return -1;
}
conn->buffer_size = buffer_size;
pbsz = strstr(conn->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 negiociate the protection level. */
code = ftp_send_command(conn, "PROT %c", level_to_char(level));
if(code < 0)
return -1;
if(code/100 != 2) {
failf(conn->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 connectdata *conn)
{
int ret;
struct Curl_easy *data = conn->data;
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 == NULL) {
failf(data, "Failed realloc of size %u", 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.\n",
mech->name);
return CURLE_FAILED_INIT;
}
}
infof(data, "Trying mechanism %s...\n", mech->name);
ret = ftp_send_command(conn, "AUTH %s", mech->name);
if(ret < 0)
/* FIXME: This error is too generic but it is OK for now. */
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).\n", mech->name);
break;
case 534:
infof(data, "Mechanism %s was rejected by the server (server returned "
"ftp code: 534).\n", mech->name);
break;
default:
if(ret/100 == 5) {
infof(data, "server does not support the security extensions\n");
return CURLE_USE_SSL_FAILED;
}
break;
}
return CURLE_LOGIN_DENIED;
}
/* Authenticate */
ret = mech->auth(conn->app_data, conn);
if(ret != AUTH_CONTINUE) {
if(ret != AUTH_OK) {
/* Mechanism has dumped the error to stderr, don't error here. */
return -1;
}
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(conn);
}
return CURLE_OK;
}
CURLcode
Curl_sec_login(struct connectdata *conn)
{
return choose_mech(conn);
}
void
Curl_sec_end(struct connectdata *conn)
{
if(conn->mech != NULL && 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;
/* FIXME: Is this really needed? */
conn->in_buffer.eof_flag = 0;
}
conn->sec_complete = 0;
conn->data_prot = PROT_CLEAR;
conn->mech = NULL;
}
#endif /* HAVE_GSSAPI */
#endif /* CURL_DISABLE_FTP */