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Minor tweaks and improvements to the tunala demo.

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- Add "-cipher" and "-out_state" command line arguments to control SSL
  cipher-suites and handshake debug output respectively.

- Implemented error handling for SSL handshakes that break down. This uses
  a cheat - storing a non-NULL pointer as "app_data" in the SSL structure
  when the SSL should be killed.
This commit is contained in:
Geoff Thorpe 2000-11-28 23:27:23 +00:00
parent b984cd2b01
commit 4aa69fe0b6
6 changed files with 144 additions and 23 deletions
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5
demos/tunala/Makefile
View File

@ -17,8 +17,8 @@ COMPILE=$(CC) $(CFLAGS) -c
# Edit, particularly the "-ldl" if not building with "dlfcn" support
LINK_FLAGS=-L$(SSL_LIBDIR) -lssl -lcrypto -ldl
SRCS=buffer.c ip.c sm.c tunala.c
OBJS=buffer.o ip.o sm.o tunala.o
SRCS=buffer.c cb.c ip.c sm.c tunala.c
OBJS=buffer.o cb.o ip.o sm.o tunala.o
TARGETS=tunala
@ -35,6 +35,7 @@ tunala: $(OBJS)
# Extra dependencies, should really use makedepend
buffer.o: buffer.c tunala.h
cb.o: cb.c tunala.h
ip.o: ip.c tunala.h
sm.o: sm.c tunala.h
tunala.o: tunala.c tunala.h

35
demos/tunala/buffer.c
View File

@ -101,6 +101,37 @@ int buffer_to_fd(buffer_t *buf, int fd)
#ifndef NO_OPENSSL
static void int_ssl_check(SSL *s, int ret)
{
int e = SSL_get_error(s, ret);
switch(e) {
/* These seem to be harmless and already "dealt with" by our
* non-blocking environment. NB: "ZERO_RETURN" is the clean
* "error" indicating a successfully closed SSL tunnel. We let
* this happen because our IO loop should not appear to have
* broken on this condition - and outside the IO loop, the
* "shutdown" state is checked. */
case SSL_ERROR_NONE:
case SSL_ERROR_WANT_READ:
case SSL_ERROR_WANT_WRITE:
case SSL_ERROR_WANT_X509_LOOKUP:
case SSL_ERROR_ZERO_RETURN:
return;
/* These seem to be indications of a genuine error that should
* result in the SSL tunnel being regarded as "dead". */
case SSL_ERROR_SYSCALL:
case SSL_ERROR_SSL:
SSL_set_app_data(s, (char *)1);
return;
default:
break;
}
/* For any other errors that (a) exist, and (b) crop up - we need to
* interpret what to do with them - so "politely inform" the caller that
* the code needs updating here. */
abort();
}
void buffer_from_SSL(buffer_t *buf, SSL *ssl)
{
int ret;
@ -109,6 +140,8 @@ void buffer_from_SSL(buffer_t *buf, SSL *ssl)
ret = SSL_read(ssl, buf->data + buf->used, buffer_unused(buf));
if(ret > 0)
buf->used += ret;
if(ret < 0)
int_ssl_check(ssl, ret);
}
void buffer_to_SSL(buffer_t *buf, SSL *ssl)
@ -119,6 +152,8 @@ void buffer_to_SSL(buffer_t *buf, SSL *ssl)
ret = SSL_write(ssl, buf->data, buf->used);
if(ret > 0)
buffer_takedata(buf, NULL, ret);
if(ret < 0)
int_ssl_check(ssl, ret);
}
void buffer_from_BIO(buffer_t *buf, BIO *bio)

39
demos/tunala/cb.c Normal file
View File

@ -0,0 +1,39 @@
#include "tunala.h"
#ifndef NO_OPENSSL
/* For callbacks generating output, here are their file-descriptors. */
static FILE *fp_cb_ssl_info = NULL;
/* This function is largely borrowed from the one used in OpenSSL's "s_client"
* and "s_server" utilities. */
void cb_ssl_info(SSL *s, int where, int ret)
{
char *str1, *str2;
int w;
if(!fp_cb_ssl_info)
return;
w = where & ~SSL_ST_MASK;
str1 = (w & SSL_ST_CONNECT ? "SSL_connect" : (w & SSL_ST_ACCEPT ?
"SSL_accept" : "undefined")),
str2 = SSL_state_string_long(s);
if (where & SSL_CB_LOOP)
fprintf(stderr, "%s:%s\n", str1, str2);
else if (where & SSL_CB_EXIT) {
if (ret == 0)
fprintf(stderr, "%s:failed in %s\n", str1, str2);
else if (ret < 0)
fprintf(stderr, "%s:error in %s\n", str1, str2);
}
}
void cb_ssl_info_set_output(FILE *fp)
{
fp_cb_ssl_info = fp;
}
#endif /* !defined(NO_OPENSSL) */

19
demos/tunala/sm.c
View File

@ -55,7 +55,7 @@ SSL *state_machine_get_SSL(state_machine_t *machine)
return machine->ssl;
}
void state_machine_set_SSL(state_machine_t *machine, SSL *ssl, int is_server)
int state_machine_set_SSL(state_machine_t *machine, SSL *ssl, int is_server)
{
if(machine->ssl)
/* Shouldn't ever be set twice */
@ -75,7 +75,7 @@ void state_machine_set_SSL(state_machine_t *machine, SSL *ssl, int is_server)
/* If we're the first one to generate traffic - do it now otherwise we
* go into the next select empty-handed and our peer will not send data
* but will similarly wait for us. */
state_machine_churn(machine);
return state_machine_churn(machine);
}
/* Performs the data-IO loop and returns zero if the machine should close */
@ -98,13 +98,14 @@ int state_machine_churn(state_machine_t *machine)
/* Still buffered data on the clean side to go out */
return 1;
}
if(SSL_get_shutdown(machine->ssl)) {
/* An SSL shutdown was underway */
if(buffer_empty(&machine->dirty_out)) {
/* Great, we can seal off the dirty side completely */
if(!state_machine_close_dirty(machine))
return 0;
}
/* We close on the SSL side if the info callback noticed some problems
* or an SSL shutdown was underway and shutdown traffic had all been
* sent. */
if(SSL_get_app_data(machine->ssl) || (SSL_get_shutdown(machine->ssl) &&
buffer_empty(&machine->dirty_out))) {
/* Great, we can seal off the dirty side completely */
if(!state_machine_close_dirty(machine))
return 0;
}
/* Either the SSL is alive and well, or the closing process still has
* outgoing data waiting to be sent */

63
demos/tunala/tunala.c
View File

@ -67,7 +67,8 @@ typedef struct _tunala_world_t {
/*****************************/
static SSL_CTX *initialise_ssl_ctx(int server_mode, const char *engine_id,
const char *CAfile, const char *cert, const char *key);
const char *CAfile, const char *cert, const char *key,
const char *cipher_list, int out_state);
static void selector_init(tunala_selector_t *selector);
static void selector_add_listener(tunala_selector_t *selector, int fd);
static void selector_add_tunala(tunala_selector_t *selector, tunala_item_t *t);
@ -92,6 +93,8 @@ static const char *def_cert = NULL;
static const char *def_key = NULL;
static const char *def_engine_id = NULL;
static int def_server_mode = 0;
static const char *def_cipher_list = NULL;
static int def_out_state = 0;
static const char *helpstring =
"\n'Tunala' (A tunneler with a New Zealand accent)\n"
@ -104,6 +107,8 @@ static const char *helpstring =
" -key <path|NULL> (default = whatever '-cert' is)\n"
" -engine <id|NULL> (default = NULL)\n"
" -server <0|1> (default = 0, ie. an SSL client)\n"
" -cipher <list> (specifies cipher list to use)\n"
" -out_state (prints SSL handshake states)\n"
" -<h|help|?> (displays this help screen)\n"
"NB: It is recommended to specify a cert+key when operating as an\n"
"SSL server. If you only specify '-cert', the same file must\n"
@ -178,6 +183,8 @@ int main(int argc, char *argv[])
const char *key = def_key;
const char *engine_id = def_engine_id;
int server_mode = def_server_mode;
const char *cipher_list = def_cipher_list;
int out_state = def_out_state;
/* Parse command-line arguments */
next_arg:
@ -242,6 +249,15 @@ next_arg:
if(!parse_server_mode(*argv, &server_mode))
return 1;
goto next_arg;
} else if(strcmp(*argv, "-cipher") == 0) {
if(argc < 2)
return usage("-cipher requires an argument", 0);
argc--; argv++;
cipher_list = *argv;
goto next_arg;
} else if(strcmp(*argv, "-out_state") == 0) {
out_state = 1;
goto next_arg;
} else if((strcmp(*argv, "-h") == 0) ||
(strcmp(*argv, "-help") == 0) ||
(strcmp(*argv, "-?") == 0)) {
@ -257,7 +273,7 @@ next_arg:
err_str0("ip_initialise succeeded");
/* Create the SSL_CTX */
if((world.ssl_ctx = initialise_ssl_ctx(server_mode, engine_id,
cacert, cert, key)) == NULL)
cacert, cert, key, cipher_list, out_state)) == NULL)
return err_str1("initialise_ssl_ctx(engine_id=%s) failed",
(engine_id == NULL) ? "NULL" : engine_id);
err_str1("initialise_ssl_ctx(engine_id=%s) succeeded",
@ -306,12 +322,11 @@ main_loop:
&newfd) == 1)) {
/* We have a new connection */
if(!tunala_world_new_item(&world, newfd,
proxy_ip, proxy_port)) {
proxy_ip, proxy_port))
fprintf(stderr, "tunala_world_new_item failed\n");
abort();
}
fprintf(stderr, "Info, new tunnel opened, now up to %d\n",
world.tunnels_used);
else
fprintf(stderr, "Info, new tunnel opened, now up to "
"%d\n", world.tunnels_used);
}
/* Give each tunnel its moment, note the while loop is because it makes
* the logic easier than with "for" to deal with an array that may shift
@ -344,7 +359,8 @@ main_loop:
/****************/
static SSL_CTX *initialise_ssl_ctx(int server_mode, const char *engine_id,
const char *CAfile, const char *cert, const char *key)
const char *CAfile, const char *cert, const char *key,
const char *cipher_list, int out_state)
{
SSL_CTX *ctx, *ret = NULL;
SSL_METHOD *meth;
@ -439,6 +455,23 @@ static SSL_CTX *initialise_ssl_ctx(int server_mode, const char *engine_id,
} else
fprintf(stderr, "Info, operating without a cert or key\n");
/* cipher_list */
if(cipher_list) {
if(!SSL_CTX_set_cipher_list(ctx, cipher_list)) {
fprintf(stderr, "Error setting cipher list '%s'\n",
cipher_list);
goto err;
}
fprintf(stderr, "Info, set cipher list '%s'\n", cipher_list);
} else
fprintf(stderr, "Info, operating with default cipher list\n");
/* out_state (output of SSL handshake states to screen). */
if(out_state) {
SSL_CTX_set_info_callback(ctx, cb_ssl_info);
cb_ssl_info_set_output(stderr);
}
/* Success! */
ret = ctx;
err:
@ -577,9 +610,15 @@ static int tunala_world_new_item(tunala_world_t *world, int fd,
{
tunala_item_t *item;
int newfd;
SSL *new_ssl = NULL;
if(!tunala_world_make_room(world))
return 0;
if((new_ssl = SSL_new(world->ssl_ctx)) == NULL) {
fprintf(stderr, "Error creating new SSL\n");
ERR_print_errors_fp(stderr);
return 0;
}
item = world->tunnels + (world->tunnels_used++);
state_machine_init(&item->sm);
item->clean_read = item->clean_send =
@ -596,11 +635,13 @@ static int tunala_world_new_item(tunala_world_t *world, int fd,
item->clean_read = item->clean_send = fd;
item->dirty_read = item->dirty_send = newfd;
}
state_machine_set_SSL(&item->sm, SSL_new(world->ssl_ctx),
world->server_mode);
/* We use the SSL's "app_data" to indicate a call-back induced "kill" */
SSL_set_app_data(new_ssl, NULL);
if(!state_machine_set_SSL(&item->sm, new_ssl, world->server_mode))
goto err;
return 1;
err:
state_machine_close(&item->sm);
tunala_world_del_item(world, world->tunnels_used - 1);
return 0;
}

6
demos/tunala/tunala.h
View File

@ -89,6 +89,10 @@ void buffer_from_SSL(buffer_t *buf, SSL *ssl);
void buffer_to_SSL(buffer_t *buf, SSL *ssl);
void buffer_from_BIO(buffer_t *buf, BIO *bio);
void buffer_to_BIO(buffer_t *buf, BIO *bio);
/* Callbacks */
void cb_ssl_info(SSL *s, int where, int ret);
void cb_ssl_info_set_output(FILE *fp); /* Called if output should be sent too */
#endif /* !defined(NO_OPENSSL) */
#endif /* !defined(NO_BUFFER) */
@ -111,7 +115,7 @@ void state_machine_init(state_machine_t *machine);
void state_machine_close(state_machine_t *machine);
buffer_t *state_machine_get_buffer(state_machine_t *machine, sm_buffer_t type);
SSL *state_machine_get_SSL(state_machine_t *machine);
void state_machine_set_SSL(state_machine_t *machine, SSL *ssl, int is_server);
int state_machine_set_SSL(state_machine_t *machine, SSL *ssl, int is_server);
/* Performs the data-IO loop and returns zero if the machine should close */
int state_machine_churn(state_machine_t *machine);
/* Is used to handle closing conditions - namely when one side of the tunnel has