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| Current File : //usr/src/crypto/heimdal/appl/ftp/ftpd/security.c |
/*
* Copyright (c) 1998-2002, 2005 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.
*/
#ifdef FTP_SERVER
#include "ftpd_locl.h"
#else
#include "ftp_locl.h"
#endif
RCSID("$Id: security.c 21225 2007-06-20 10:16:02Z lha $");
static enum protection_level command_prot;
static enum protection_level data_prot;
static size_t buffer_size;
struct buffer {
void *data;
size_t size;
size_t index;
int eof_flag;
};
static struct buffer in_buffer, out_buffer;
int sec_complete;
static struct {
enum protection_level level;
const char *name;
} level_names[] = {
{ prot_clear, "clear" },
{ prot_safe, "safe" },
{ prot_confidential, "confidential" },
{ prot_private, "private" }
};
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";
}
#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
static void *app_data;
int
sec_getc(FILE *F)
{
if(sec_complete && data_prot) {
char c;
if(sec_read(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(int fd, struct buffer *buf, int level)
{
int len;
int b;
void *tmp;
b = block_read(fd, &len, sizeof(len));
if (b == 0)
return 0;
else if (b < 0)
return -1;
len = ntohl(len);
tmp = realloc(buf->data, len);
if (tmp == NULL)
return -1;
buf->data = tmp;
b = block_read(fd, buf->data, len);
if (b == 0)
return 0;
else if (b < 0)
return -1;
buf->size = (*mech->decode)(app_data, buf->data, len, data_prot);
buf->index = 0;
return 0;
}
static size_t
buffer_read(struct buffer *buf, void *dataptr, size_t len)
{
len = min(len, buf->size - buf->index);
memcpy(dataptr, (char*)buf->data + buf->index, len);
buf->index += len;
return len;
}
static size_t
buffer_write(struct buffer *buf, void *dataptr, 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, dataptr, len);
buf->index += len;
return len;
}
int
sec_read(int fd, void *dataptr, int length)
{
size_t len;
int rx = 0;
if(sec_complete == 0 || data_prot == 0)
return read(fd, dataptr, length);
if(in_buffer.eof_flag){
in_buffer.eof_flag = 0;
return 0;
}
len = buffer_read(&in_buffer, dataptr, length);
length -= len;
rx += len;
dataptr = (char*)dataptr + len;
while(length){
int ret;
ret = sec_get_data(fd, &in_buffer, data_prot);
if (ret < 0)
return -1;
if(ret == 0 && in_buffer.size == 0) {
if(rx)
in_buffer.eof_flag = 1;
return rx;
}
len = buffer_read(&in_buffer, dataptr, length);
length -= len;
rx += len;
dataptr = (char*)dataptr + len;
}
return rx;
}
static int
sec_send(int fd, char *from, int length)
{
int bytes;
void *buf;
bytes = (*mech->encode)(app_data, from, length, data_prot, &buf);
bytes = htonl(bytes);
block_write(fd, &bytes, sizeof(bytes));
block_write(fd, buf, ntohl(bytes));
free(buf);
return length;
}
int
sec_fflush(FILE *F)
{
if(data_prot != prot_clear) {
if(out_buffer.index > 0){
sec_write(fileno(F), out_buffer.data, out_buffer.index);
out_buffer.index = 0;
}
sec_send(fileno(F), NULL, 0);
}
fflush(F);
return 0;
}
int
sec_write(int fd, char *dataptr, int length)
{
int len = buffer_size;
int tx = 0;
if(data_prot == prot_clear)
return write(fd, dataptr, length);
len -= (*mech->overhead)(app_data, data_prot, len);
while(length){
if(length < len)
len = length;
sec_send(fd, dataptr, len);
length -= len;
dataptr += len;
tx += len;
}
return tx;
}
int
sec_vfprintf2(FILE *f, const char *fmt, va_list ap)
{
char *buf;
int ret;
if(data_prot == prot_clear)
return vfprintf(f, fmt, ap);
else {
int len;
len = vasprintf(&buf, fmt, ap);
if (len == -1)
return len;
ret = buffer_write(&out_buffer, buf, len);
free(buf);
return ret;
}
}
int
sec_fprintf2(FILE *f, const char *fmt, ...)
{
int ret;
va_list ap;
va_start(ap, fmt);
ret = sec_vfprintf2(f, fmt, ap);
va_end(ap);
return ret;
}
int
sec_putc(int c, FILE *F)
{
char ch = c;
if(data_prot == prot_clear)
return putc(c, F);
buffer_write(&out_buffer, &ch, 1);
if(c == '\n' || out_buffer.index >= 1024 /* XXX */) {
sec_write(fileno(F), out_buffer.data, out_buffer.index);
out_buffer.index = 0;
}
return c;
}
int
sec_read_msg(char *s, int level)
{
int len;
char *buf;
int return_code;
buf = malloc(strlen(s));
len = base64_decode(s + 4, buf); /* XXX */
len = (*mech->decode)(app_data, buf, len, level);
if(len < 0)
return -1;
buf[len] = '\0';
if(buf[3] == '-')
return_code = 0;
else
sscanf(buf, "%d", &return_code);
if(buf[len-1] == '\n')
buf[len-1] = '\0';
strcpy(s, buf);
free(buf);
return return_code;
}
int
sec_vfprintf(FILE *f, const char *fmt, va_list ap)
{
char *buf;
void *enc;
int len;
if(!sec_complete)
return vfprintf(f, fmt, ap);
if (vasprintf(&buf, fmt, ap) == -1) {
printf("Failed to allocate command.\n");
return -1;
}
len = (*mech->encode)(app_data, buf, strlen(buf), command_prot, &enc);
free(buf);
if(len < 0) {
printf("Failed to encode command.\n");
return -1;
}
if(base64_encode(enc, len, &buf) < 0){
free(enc);
printf("Out of memory base64-encoding.\n");
return -1;
}
free(enc);
#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(command_prot == prot_safe)
fprintf(f, "MIC %s", buf);
else if(command_prot == prot_private)
fprintf(f, "ENC %s", buf);
else if(command_prot == prot_confidential)
fprintf(f, "CONF %s", buf);
#endif
free(buf);
return 0;
}
int
sec_fprintf(FILE *f, const char *fmt, ...)
{
va_list ap;
int ret;
va_start(ap, fmt);
ret = sec_vfprintf(f, fmt, ap);
va_end(ap);
return ret;
}
/* end common stuff */
#ifdef FTP_SERVER
int ccc_passed;
void
auth(char *auth_name)
{
int i;
void *tmp;
for(i = 0; (mech = mechs[i]) != NULL; i++){
if(!strcasecmp(auth_name, mech->name)){
tmp = realloc(app_data, mech->size);
if (tmp == NULL) {
reply(431, "Unable to accept %s at this time", mech->name);
return;
}
app_data = tmp;
if(mech->init && (*mech->init)(app_data) != 0) {
reply(431, "Unable to accept %s at this time", mech->name);
return;
}
if(mech->auth) {
(*mech->auth)(app_data);
return;
}
if(mech->adat)
reply(334, "Send authorization data.");
else
reply(234, "Authorization complete.");
return;
}
}
free (app_data);
app_data = NULL;
reply(504, "%s is unknown to me", auth_name);
}
void
adat(char *auth_data)
{
if(mech && !sec_complete) {
void *buf = malloc(strlen(auth_data));
size_t len;
len = base64_decode(auth_data, buf);
(*mech->adat)(app_data, buf, len);
free(buf);
} else
reply(503, "You must %sissue an AUTH first.", mech ? "re-" : "");
}
void pbsz(int size)
{
size_t new = size;
if(!sec_complete)
reply(503, "Incomplete security data exchange.");
if(mech->pbsz)
new = (*mech->pbsz)(app_data, size);
if(buffer_size != new){
buffer_size = size;
}
if(new != size)
reply(200, "PBSZ=%lu", (unsigned long)new);
else
reply(200, "OK");
}
void
prot(char *pl)
{
int p = -1;
if(buffer_size == 0){
reply(503, "No protection buffer size negotiated.");
return;
}
if(!strcasecmp(pl, "C"))
p = prot_clear;
else if(!strcasecmp(pl, "S"))
p = prot_safe;
else if(!strcasecmp(pl, "E"))
p = prot_confidential;
else if(!strcasecmp(pl, "P"))
p = prot_private;
else {
reply(504, "Unrecognized protection level.");
return;
}
if(sec_complete){
if((*mech->check_prot)(app_data, p)){
reply(536, "%s does not support %s protection.",
mech->name, level_to_name(p));
}else{
data_prot = (enum protection_level)p;
reply(200, "Data protection is %s.", level_to_name(p));
}
}else{
reply(503, "Incomplete security data exchange.");
}
}
void ccc(void)
{
if(sec_complete){
if(mech->ccc && (*mech->ccc)(app_data) == 0) {
command_prot = data_prot = prot_clear;
ccc_passed = 1;
} else
reply(534, "You must be joking.");
}else
reply(503, "Incomplete security data exchange.");
}
void mec(char *msg, enum protection_level level)
{
void *buf;
size_t len, buf_size;
if(!sec_complete) {
reply(503, "Incomplete security data exchange.");
return;
}
buf_size = strlen(msg) + 2;
buf = malloc(buf_size);
len = base64_decode(msg, buf);
command_prot = level;
if(len == (size_t)-1) {
reply(501, "Failed to base64-decode command");
return;
}
len = (*mech->decode)(app_data, buf, len, level);
if(len == (size_t)-1) {
reply(535, "Failed to decode command");
return;
}
((char*)buf)[len] = '\0';
if(strstr((char*)buf, "\r\n") == NULL)
strlcat((char*)buf, "\r\n", buf_size);
new_ftp_command(buf);
}
/* ------------------------------------------------------------ */
int
sec_userok(char *userstr)
{
if(sec_complete)
return (*mech->userok)(app_data, userstr);
return 0;
}
int
sec_session(char *user)
{
if(sec_complete && mech->session)
return (*mech->session)(app_data, user);
return 0;
}
char *ftp_command;
void
new_ftp_command(char *command)
{
ftp_command = command;
}
void
delete_ftp_command(void)
{
free(ftp_command);
ftp_command = NULL;
}
int
secure_command(void)
{
return ftp_command != NULL;
}
enum protection_level
get_command_prot(void)
{
return command_prot;
}
#else /* FTP_SERVER */
void
sec_status(void)
{
if(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");
}
}
static int
sec_prot_internal(int level)
{
int ret;
char *p;
unsigned int s = 1048576;
int old_verbose = verbose;
verbose = 0;
if(!sec_complete){
printf("No security data exchange has taken place.\n");
return -1;
}
if(level){
ret = command("PBSZ %u", s);
if(ret != COMPLETE){
printf("Failed to set protection buffer size.\n");
return -1;
}
buffer_size = s;
p = strstr(reply_string, "PBSZ=");
if(p)
sscanf(p, "PBSZ=%u", &s);
if(s < buffer_size)
buffer_size = s;
}
verbose = old_verbose;
ret = command("PROT %c", level["CSEP"]); /* XXX :-) */
if(ret != COMPLETE){
printf("Failed to set protection level.\n");
return -1;
}
data_prot = (enum protection_level)level;
return 0;
}
enum protection_level
set_command_prot(enum protection_level level)
{
int ret;
enum protection_level old = command_prot;
if(level != command_prot && level == prot_clear) {
ret = command("CCC");
if(ret != COMPLETE) {
printf("Failed to clear command channel.\n");
return -1;
}
}
command_prot = level;
return old;
}
void
sec_prot(int argc, char **argv)
{
int level = -1;
if(argc > 3)
goto usage;
if(argc == 1) {
sec_status();
return;
}
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)(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) {
if(set_command_prot(level) < 0) {
code = -1;
return;
}
} else
goto usage;
code = 0;
return;
usage:
printf("usage: %s [command|data] [clear|safe|confidential|private]\n",
argv[0]);
code = -1;
}
void
sec_prot_command(int argc, char **argv)
{
int level;
if(argc > 2)
goto usage;
if(!sec_complete) {
printf("No security data exchange has taken place.\n");
code = -1;
return;
}
if(argc == 1) {
sec_status();
} else {
level = name_to_level(argv[1]);
if(level == -1)
goto usage;
if((*mech->check_prot)(app_data, level)) {
printf("%s does not implement %s protection.\n",
mech->name, level_to_name(level));
code = -1;
return;
}
if(set_command_prot(level) < 0) {
code = -1;
return;
}
}
code = 0;
return;
usage:
printf("usage: %s [clear|safe|confidential|private]\n",
argv[0]);
code = -1;
}
static enum protection_level request_data_prot;
void
sec_set_protection_level(void)
{
if(sec_complete && data_prot != request_data_prot)
sec_prot_internal(request_data_prot);
}
int
sec_request_prot(char *level)
{
int l = name_to_level(level);
if(l == -1)
return -1;
request_data_prot = (enum protection_level)l;
return 0;
}
int
sec_login(char *host)
{
int ret;
struct sec_client_mech **m;
int old_verbose = verbose;
verbose = -1; /* shut up all messages this will produce (they
are usually not very user friendly) */
for(m = mechs; *m && (*m)->name; m++) {
void *tmp;
tmp = realloc(app_data, (*m)->size);
if (tmp == NULL) {
warnx ("realloc %lu failed", (unsigned long)(*m)->size);
return -1;
}
app_data = tmp;
if((*m)->init && (*(*m)->init)(app_data) != 0) {
printf("Skipping %s...\n", (*m)->name);
continue;
}
printf("Trying %s...\n", (*m)->name);
ret = command("AUTH %s", (*m)->name);
if(ret != CONTINUE){
if(code == 504){
printf("%s is not supported by the server.\n", (*m)->name);
}else if(code == 534){
printf("%s rejected as security mechanism.\n", (*m)->name);
}else if(ret == ERROR) {
printf("The server doesn't support the FTP "
"security extensions.\n");
verbose = old_verbose;
return -1;
}
continue;
}
ret = (*(*m)->auth)(app_data, host);
if(ret == AUTH_CONTINUE)
continue;
else if(ret != AUTH_OK){
/* mechanism is supposed to output error string */
verbose = old_verbose;
return -1;
}
mech = *m;
sec_complete = 1;
if(doencrypt) {
command_prot = prot_private;
request_data_prot = prot_private;
} else {
command_prot = prot_safe;
}
break;
}
verbose = old_verbose;
return *m == NULL;
}
void
sec_end(void)
{
if (mech != NULL) {
if(mech->end)
(*mech->end)(app_data);
if (app_data != NULL) {
memset(app_data, 0, mech->size);
free(app_data);
app_data = NULL;
}
}
sec_complete = 0;
data_prot = (enum protection_level)0;
}
#endif /* FTP_SERVER */