curl/lib/security.c

670 lines
16 KiB
C

/* modified by Martin Hedenfalk <mhe@stacken.kth.se> for use in Curl
* last modified 2000-09-18
* Even more obscurified to merge better into libcurl by Daniel Stenberg.
*/
/*
* Copyright (c) 1998, 1999 Kungliga Tekniska Högskolan
* (Royal Institute of Technology, Stockholm, Sweden).
* 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 "setup.h"
#ifdef KRB4
#define _MPRINTF_REPLACE /* we want curl-functions instead of native ones */
#include <curl/mprintf.h>
#include "security.h"
#include <stdlib.h>
#include <string.h>
#include <netdb.h>
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#include "base64.h"
#include "sendf.h"
#include "ftp.h"
/* The last #include file should be: */
#ifdef MALLOCDEBUG
#include "memdebug.h"
#endif
#define min(a, b) ((a) < (b) ? (a) : (b))
static struct {
enum protection_level level;
const char *name;
} level_names[] = {
{ prot_clear, "clear" },
{ prot_safe, "safe" },
{ prot_confidential, "confidential" },
{ prot_private, "private" }
};
#if 0
static const char *
level_to_name(enum protection_level level)
{
int i;
for(i = 0; i < sizeof(level_names) / sizeof(level_names[0]); i++)
if(level_names[i].level == level)
return level_names[i].name;
return "unknown";
}
#endif
#ifndef FTP_SERVER /* not used in server */
static enum protection_level
name_to_level(const char *name)
{
int i;
for(i = 0; i < sizeof(level_names) / sizeof(level_names[0]); i++)
if(!strncasecmp(level_names[i].name, name, strlen(name)))
return level_names[i].level;
return (enum protection_level)-1;
}
#endif
#ifdef FTP_SERVER
static struct sec_server_mech *mechs[] = {
#ifdef KRB5
&gss_server_mech,
#endif
#ifdef KRB4
&krb4_server_mech,
#endif
NULL
};
static struct sec_server_mech *mech;
#else
static struct sec_client_mech *mechs[] = {
#ifdef KRB5
&gss_client_mech,
#endif
#ifdef KRB4
&krb4_client_mech,
#endif
NULL
};
static struct sec_client_mech *mech;
#endif
int
sec_getc(struct connectdata *conn, FILE *F)
{
if(conn->sec_complete && conn->data_prot) {
char c;
if(sec_read(conn, fileno(F), &c, 1) <= 0)
return EOF;
return c;
} else
return getc(F);
}
static int
block_read(int fd, void *buf, size_t len)
{
unsigned char *p = buf;
int b;
while(len) {
b = read(fd, p, len);
if (b == 0)
return 0;
else if (b < 0)
return -1;
len -= b;
p += b;
}
return p - (unsigned char*)buf;
}
static int
block_write(int fd, void *buf, size_t len)
{
unsigned char *p = buf;
int b;
while(len) {
b = write(fd, p, len);
if(b < 0)
return -1;
len -= b;
p += b;
}
return p - (unsigned char*)buf;
}
static int
sec_get_data(struct connectdata *conn,
int fd, struct krb4buffer *buf, int level)
{
int len;
int b;
b = block_read(fd, &len, sizeof(len));
if (b == 0)
return 0;
else if (b < 0)
return -1;
len = ntohl(len);
buf->data = realloc(buf->data, len);
b = block_read(fd, buf->data, len);
if (b == 0)
return 0;
else if (b < 0)
return -1;
buf->size = (*mech->decode)(conn->app_data, buf->data, len,
conn->data_prot, conn);
buf->index = 0;
return 0;
}
static size_t
buffer_read(struct krb4buffer *buf, void *data, size_t len)
{
len = min(len, buf->size - buf->index);
memcpy(data, (char*)buf->data + buf->index, len);
buf->index += len;
return len;
}
static size_t
buffer_write(struct krb4buffer *buf, void *data, size_t len)
{
if(buf->index + len > buf->size) {
void *tmp;
if(buf->data == NULL)
tmp = malloc(1024);
else
tmp = realloc(buf->data, buf->index + len);
if(tmp == NULL)
return -1;
buf->data = tmp;
buf->size = buf->index + len;
}
memcpy((char*)buf->data + buf->index, data, len);
buf->index += len;
return len;
}
int
sec_read(struct connectdata *conn, int fd, void *buffer, int length)
{
size_t len;
int rx = 0;
if(conn->sec_complete == 0 || conn->data_prot == 0)
return read(fd, buffer, length);
if(conn->in_buffer.eof_flag){
conn->in_buffer.eof_flag = 0;
return 0;
}
len = buffer_read(&conn->in_buffer, buffer, length);
length -= len;
rx += len;
buffer = (char*)buffer + len;
while(length) {
if(sec_get_data(conn, fd, &conn->in_buffer, conn->data_prot) < 0)
return -1;
if(conn->in_buffer.size == 0) {
if(rx)
conn->in_buffer.eof_flag = 1;
return rx;
}
len = buffer_read(&conn->in_buffer, buffer, length);
length -= len;
rx += len;
buffer = (char*)buffer + len;
}
return rx;
}
static int
sec_send(struct connectdata *conn, int fd, char *from, int length)
{
int bytes;
void *buf;
bytes = (*mech->encode)(conn->app_data, from, length, conn->data_prot, &buf, conn);
bytes = htonl(bytes);
block_write(fd, &bytes, sizeof(bytes));
block_write(fd, buf, ntohl(bytes));
free(buf);
return length;
}
int
sec_fflush(struct connectdata *conn, FILE *F)
{
if(conn->data_prot != prot_clear) {
if(conn->out_buffer.index > 0){
sec_write(conn, fileno(F),
conn->out_buffer.data, conn->out_buffer.index);
conn->out_buffer.index = 0;
}
sec_send(conn, fileno(F), NULL, 0);
}
fflush(F);
return 0;
}
int
sec_fflush_fd(struct connectdata *conn, int fd)
{
if(conn->data_prot != prot_clear) {
if(conn->out_buffer.index > 0){
sec_write(conn, fd,
conn->out_buffer.data, conn->out_buffer.index);
conn->out_buffer.index = 0;
}
sec_send(conn, fd, NULL, 0);
}
return 0;
}
int
sec_write(struct connectdata *conn, int fd, char *buffer, int length)
{
int len = conn->buffer_size;
int tx = 0;
if(conn->data_prot == prot_clear)
return write(fd, buffer, length);
len -= (*mech->overhead)(conn->app_data, conn->data_prot, len);
while(length){
if(length < len)
len = length;
sec_send(conn, fd, buffer, len);
length -= len;
buffer += len;
tx += len;
}
return tx;
}
int
sec_vfprintf2(struct connectdata *conn, FILE *f, const char *fmt, va_list ap)
{
char *buf;
int ret;
if(conn->data_prot == prot_clear)
return vfprintf(f, fmt, ap);
else {
buf = aprintf(fmt, ap);
ret = buffer_write(&conn->out_buffer, buf, strlen(buf));
free(buf);
return ret;
}
}
int
sec_fprintf2(struct connectdata *conn, FILE *f, const char *fmt, ...)
{
int ret;
va_list ap;
va_start(ap, fmt);
ret = sec_vfprintf2(conn, f, fmt, ap);
va_end(ap);
return ret;
}
int
sec_putc(struct connectdata *conn, int c, FILE *F)
{
char ch = c;
if(conn->data_prot == prot_clear)
return putc(c, F);
buffer_write(&conn->out_buffer, &ch, 1);
if(c == '\n' || conn->out_buffer.index >= 1024 /* XXX */) {
sec_write(conn, fileno(F), conn->out_buffer.data, conn->out_buffer.index);
conn->out_buffer.index = 0;
}
return c;
}
int
sec_read_msg(struct connectdata *conn, char *s, int level)
{
int len;
char *buf;
int code;
buf = malloc(strlen(s));
len = Curl_base64_decode(s + 4, buf); /* XXX */
len = (*mech->decode)(conn->app_data, buf, len, level, conn);
if(len < 0)
return -1;
buf[len] = '\0';
if(buf[3] == '-')
code = 0;
else
sscanf(buf, "%d", &code);
if(buf[len-1] == '\n')
buf[len-1] = '\0';
strcpy(s, buf);
free(buf);
return code;
}
/* modified to return how many bytes written, or -1 on error ***/
int
sec_vfprintf(struct connectdata *conn, FILE *f, const char *fmt, va_list ap)
{
int ret = 0;
char *buf;
void *enc;
int len;
if(!conn->sec_complete)
return vfprintf(f, fmt, ap);
buf = aprintf(fmt, ap);
len = (*mech->encode)(conn->app_data, buf, strlen(buf),
conn->command_prot, &enc,
conn);
free(buf);
if(len < 0) {
failf(conn->data, "Failed to encode command.\n");
return -1;
}
if(Curl_base64_encode(enc, len, &buf) < 0){
failf(conn->data, "Out of memory base64-encoding.\n");
return -1;
}
#ifdef FTP_SERVER
if(command_prot == prot_safe)
fprintf(f, "631 %s\r\n", buf);
else if(command_prot == prot_private)
fprintf(f, "632 %s\r\n", buf);
else if(command_prot == prot_confidential)
fprintf(f, "633 %s\r\n", buf);
#else
if(conn->command_prot == prot_safe)
ret = fprintf(f, "MIC %s", buf);
else if(conn->command_prot == prot_private)
ret = fprintf(f, "ENC %s", buf);
else if(conn->command_prot == prot_confidential)
ret = fprintf(f, "CONF %s", buf);
#endif
free(buf);
return ret;
}
int
sec_fprintf(struct connectdata *conn, FILE *f, const char *fmt, ...)
{
va_list ap;
int ret;
va_start(ap, fmt);
ret = sec_vfprintf(conn, f, fmt, ap);
va_end(ap);
return ret;
}
/* end common stuff */
#ifdef FTP_SERVER
/* snip */
#else /* FTP_SERVER */
#if 0
void
sec_status(void)
{
if(conn->sec_complete){
printf("Using %s for authentication.\n", mech->name);
printf("Using %s command channel.\n", level_to_name(command_prot));
printf("Using %s data channel.\n", level_to_name(data_prot));
if(buffer_size > 0)
printf("Protection buffer size: %lu.\n",
(unsigned long)buffer_size);
}else{
printf("Not using any security mechanism.\n");
}
}
#endif
static int
sec_prot_internal(struct connectdata *conn, int level)
{
char *p;
unsigned int s = 1048576;
size_t nread;
if(!conn->sec_complete){
infof(conn->data, "No security data exchange has taken place.\n");
return -1;
}
if(level){
Curl_ftpsendf(conn->data->firstsocket, conn,
"PBSZ %u", s);
/* wait for feedback */
nread = Curl_GetFTPResponse(conn->data->firstsocket,
conn->data->buffer, conn, NULL);
if(nread < 0)
return /*CURLE_OPERATION_TIMEOUTED*/-1;
if(/*ret != COMPLETE*/conn->data->buffer[0] != '2'){
failf(conn->data, "Failed to set protection buffer size.\n");
return -1;
}
conn->buffer_size = s;
p = strstr(/*reply_string*/conn->data->buffer, "PBSZ=");
if(p)
sscanf(p, "PBSZ=%u", &s);
if(s < conn->buffer_size)
conn->buffer_size = s;
}
Curl_ftpsendf(conn->data->firstsocket, conn,
"PROT %c", level["CSEP"]);
/* wait for feedback */
nread = Curl_GetFTPResponse(conn->data->firstsocket,
conn->data->buffer, conn, NULL);
if(nread < 0)
return /*CURLE_OPERATION_TIMEOUTED*/-1;
if(/*ret != COMPLETE*/conn->data->buffer[0] != '2'){
failf(conn->data, "Failed to set protection level.\n");
return -1;
}
conn->data_prot = (enum protection_level)level;
return 0;
}
enum protection_level
set_command_prot(struct connectdata *conn, enum protection_level level)
{
enum protection_level old = conn->command_prot;
conn->command_prot = level;
return old;
}
#if 0
void
sec_prot(int argc, char **argv)
{
int level = -1;
if(argc < 2 || argc > 3)
goto usage;
if(!sec_complete) {
printf("No security data exchange has taken place.\n");
code = -1;
return;
}
level = name_to_level(argv[argc - 1]);
if(level == -1)
goto usage;
if((*mech->check_prot)(conn->app_data, level)) {
printf("%s does not implement %s protection.\n",
mech->name, level_to_name(level));
code = -1;
return;
}
if(argc == 2 || strncasecmp(argv[1], "data", strlen(argv[1])) == 0) {
if(sec_prot_internal(level) < 0){
code = -1;
return;
}
} else if(strncasecmp(argv[1], "command", strlen(argv[1])) == 0)
set_command_prot(level);
else
goto usage;
code = 0;
return;
usage:
printf("usage: %s [command|data] [clear|safe|confidential|private]\n",
argv[0]);
code = -1;
}
#endif
void
sec_set_protection_level(struct connectdata *conn)
{
if(conn->sec_complete && conn->data_prot != conn->request_data_prot)
sec_prot_internal(conn, conn->request_data_prot);
}
int
sec_request_prot(struct connectdata *conn, char *level)
{
int l = name_to_level(level);
if(l == -1)
return -1;
conn->request_data_prot = (enum protection_level)l;
return 0;
}
int
sec_login(struct connectdata *conn)
{
int ret;
struct sec_client_mech **m;
size_t nread;
struct UrlData *data=conn->data;
for(m = mechs; *m && (*m)->name; m++) {
void *tmp;
tmp = realloc(conn->app_data, (*m)->size);
if (tmp == NULL) {
failf (data, "realloc %u failed", (*m)->size);
return -1;
}
conn->app_data = tmp;
if((*m)->init && (*(*m)->init)(conn->app_data) != 0) {
infof(data, "Skipping %s...\n", (*m)->name);
continue;
}
infof(data, "Trying %s...\n", (*m)->name);
/*ret = command("AUTH %s", (*m)->name);***/
Curl_ftpsendf(conn->data->firstsocket, conn,
"AUTH %s", (*m)->name);
/* wait for feedback */
nread = Curl_GetFTPResponse(conn->data->firstsocket,
conn->data->buffer, conn, NULL);
if(nread < 0)
return /*CURLE_OPERATION_TIMEOUTED*/-1;
if(/*ret != CONTINUE*/conn->data->buffer[0] != '3'){
if(/*code == 504*/strncmp(conn->data->buffer,"504",3) == 0) {
infof(data,
"%s is not supported by the server.\n", (*m)->name);
}
else if(/*code == 534*/strncmp(conn->data->buffer,"534",3) == 0) {
infof(data, "%s rejected as security mechanism.\n", (*m)->name);
}
else if(/*ret == ERROR*/conn->data->buffer[0] == '5') {
infof(data, "The server doesn't support the FTP "
"security extensions.\n");
return -1;
}
continue;
}
ret = (*(*m)->auth)(conn->app_data, /*host***/conn);
if(ret == AUTH_CONTINUE)
continue;
else if(ret != AUTH_OK){
/* mechanism is supposed to output error string */
return -1;
}
mech = *m;
conn->sec_complete = 1;
conn->command_prot = prot_safe;
break;
}
return *m == NULL;
}
void
sec_end(struct connectdata *conn)
{
if (mech != NULL) {
if(mech->end)
(*mech->end)(conn->app_data);
memset(conn->app_data, 0, mech->size);
free(conn->app_data);
conn->app_data = NULL;
}
conn->sec_complete = 0;
conn->data_prot = (enum protection_level)0;
}
#endif /* FTP_SERVER */
#endif /* KRB4 */