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PR: 2028 

Submitted by: Robin Seggelmann <seggelmann@fh-muenster.de>
Approved by: steve@openssl.org

Fix DTLS cookie management bugs.
This commit is contained in:
Dr. Stephen Henson 2009-09-04 17:42:53 +00:00
parent 88a3dd7896
commit 07a9d1a2c2
9 changed files with 140 additions and 31 deletions
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3
apps/s_apps.h
View File

@ -171,3 +171,6 @@ void MS_CALLBACK tlsext_cb(SSL *s, int client_server, int type,
unsigned char *data, int len,
void *arg);
#endif
int MS_CALLBACK generate_cookie_callback(SSL *ssl, unsigned char *cookie, unsigned int *cookie_len);
int MS_CALLBACK verify_cookie_callback(SSL *ssl, unsigned char *cookie, unsigned int cookie_len);

88
apps/s_cb.c
View File

@ -117,13 +117,18 @@
#undef NON_MAIN
#undef USE_SOCKETS
#include <openssl/err.h>
#include <openssl/rand.h>
#include <openssl/x509.h>
#include <openssl/ssl.h>
#include "s_apps.h"
#define COOKIE_SECRET_LENGTH 16
int verify_depth=0;
int verify_error=X509_V_OK;
int verify_return_error=0;
unsigned char cookie_secret[COOKIE_SECRET_LENGTH];
int cookie_initialized=0;
int MS_CALLBACK verify_callback(int ok, X509_STORE_CTX *ctx)
{
@ -682,3 +687,86 @@ void MS_CALLBACK tlsext_cb(SSL *s, int client_server, int type,
BIO_dump(bio, (char *)data, len);
(void)BIO_flush(bio);
}
int MS_CALLBACK generate_cookie_callback(SSL *ssl, unsigned char *cookie, unsigned int *cookie_len)
{
unsigned char *buffer, result[EVP_MAX_MD_SIZE];
unsigned int length, resultlength;
struct sockaddr_in peer;
/* Initialize a random secret */
if (!cookie_initialized)
{
if (!RAND_bytes(cookie_secret, COOKIE_SECRET_LENGTH))
{
BIO_printf(bio_err,"error setting random cookie secret\n");
return 0;
}
cookie_initialized = 1;
}
/* Read peer information */
(void)BIO_dgram_get_peer(SSL_get_rbio(ssl), &peer);
/* Create buffer with peer's address and port */
length = sizeof(peer.sin_addr);
length += sizeof(peer.sin_port);
buffer = OPENSSL_malloc(length);
if (buffer == NULL)
{
BIO_printf(bio_err,"out of memory\n");
return 0;
}
memcpy(buffer, &peer.sin_addr, sizeof(peer.sin_addr));
memcpy(buffer + sizeof(peer.sin_addr), &peer.sin_port, sizeof(peer.sin_port));
/* Calculate HMAC of buffer using the secret */
HMAC(EVP_sha1(), cookie_secret, COOKIE_SECRET_LENGTH,
buffer, length, result, &resultlength);
OPENSSL_free(buffer);
memcpy(cookie, result, resultlength);
*cookie_len = resultlength;
return 1;
}
int MS_CALLBACK verify_cookie_callback(SSL *ssl, unsigned char *cookie, unsigned int cookie_len)
{
unsigned char *buffer, result[EVP_MAX_MD_SIZE];
unsigned int length, resultlength;
struct sockaddr_in peer;
/* If secret isn't initialized yet, the cookie can't be valid */
if (!cookie_initialized)
return 0;
/* Read peer information */
(void)BIO_dgram_get_peer(SSL_get_rbio(ssl), &peer);
/* Create buffer with peer's address and port */
length = sizeof(peer.sin_addr);
length += sizeof(peer.sin_port);
buffer = OPENSSL_malloc(length);
if (buffer == NULL)
{
BIO_printf(bio_err,"out of memory\n");
return 0;
}
memcpy(buffer, &peer.sin_addr, sizeof(peer.sin_addr));
memcpy(buffer + sizeof(peer.sin_addr), &peer.sin_port, sizeof(peer.sin_port));
/* Calculate HMAC of buffer using the secret */
HMAC(EVP_sha1(), cookie_secret, COOKIE_SECRET_LENGTH,
buffer, length, result, &resultlength);
OPENSSL_free(buffer);
if (cookie_len == resultlength && memcmp(result, cookie, resultlength) == 0)
return 1;
return 0;
}

4
apps/s_server.c
View File

@ -1654,6 +1654,10 @@ bad:
SSL_CTX_set_session_id_context(ctx,(void*)&s_server_session_id_context,
sizeof s_server_session_id_context);
/* Set DTLS cookie generation and verification callbacks */
SSL_CTX_set_cookie_generate_cb(ctx, generate_cookie_callback);
SSL_CTX_set_cookie_verify_cb(ctx, verify_cookie_callback);
#ifndef OPENSSL_NO_TLSEXT
if (ctx2)
{

3
crypto/bio/bio.h
View File

@ -157,6 +157,7 @@ extern "C" {
* previous write
* operation */
#define BIO_CTRL_DGRAM_GET_PEER 46
#define BIO_CTRL_DGRAM_SET_PEER 44 /* Destination for the data */
#define BIO_CTRL_DGRAM_SET_NEXT_TIMEOUT 45 /* Next DTLS handshake timeout to
@ -538,6 +539,8 @@ int BIO_ctrl_reset_read_request(BIO *b);
(int)BIO_ctrl(b, BIO_CTRL_DGRAM_GET_RECV_TIMER_EXP, 0, NULL)
#define BIO_dgram_send_timedout(b) \
(int)BIO_ctrl(b, BIO_CTRL_DGRAM_GET_SEND_TIMER_EXP, 0, NULL)
#define BIO_dgram_get_peer(b,peer) \
(int)BIO_ctrl(b, BIO_CTRL_DGRAM_GET_PEER, 0, (char *)peer)
#define BIO_dgram_set_peer(b,peer) \
(int)BIO_ctrl(b, BIO_CTRL_DGRAM_SET_PEER, 0, (char *)peer)

12
crypto/bio/bss_dgram.c
View File

@ -290,11 +290,11 @@ static int dgram_read(BIO *b, char *out, int outl)
ret=recvfrom(b->num,out,outl,0,&peer,(void *)&peerlen);
dgram_reset_rcv_timeout(b);
if ( ! data->connected && ret > 0)
BIO_ctrl(b, BIO_CTRL_DGRAM_CONNECT, 0, &peer);
if ( ! data->connected && ret >= 0)
BIO_ctrl(b, BIO_CTRL_DGRAM_SET_PEER, 0, &peer);
BIO_clear_retry_flags(b);
if (ret <= 0)
if (ret < 0)
{
if (BIO_dgram_should_retry(ret))
{
@ -518,6 +518,12 @@ static long dgram_ctrl(BIO *b, int cmd, long num, void *ptr)
memset(&(data->peer), 0x00, sizeof(struct sockaddr));
}
break;
case BIO_CTRL_DGRAM_GET_PEER:
to = (struct sockaddr *) ptr;
memcpy(to, &(data->peer), sizeof(struct sockaddr));
ret = sizeof(struct sockaddr);
break;
case BIO_CTRL_DGRAM_SET_PEER:
to = (struct sockaddr *) ptr;

16
ssl/d1_srvr.c
View File

@ -238,11 +238,6 @@ int dtls1_accept(SSL *s)
s->state=SSL3_ST_SW_HELLO_REQ_A;
}
if ( (SSL_get_options(s) & SSL_OP_COOKIE_EXCHANGE))
s->d1->send_cookie = 1;
else
s->d1->send_cookie = 0;
break;
case SSL3_ST_SW_HELLO_REQ_A:
@ -273,7 +268,7 @@ int dtls1_accept(SSL *s)
dtls1_stop_timer(s);
s->new_session = 2;
if (s->d1->send_cookie)
if (ret == 1 && (SSL_get_options(s) & SSL_OP_COOKIE_EXCHANGE))
s->state = DTLS1_ST_SW_HELLO_VERIFY_REQUEST_A;
else
s->state = SSL3_ST_SW_SRVR_HELLO_A;
@ -287,7 +282,6 @@ int dtls1_accept(SSL *s)
dtls1_start_timer(s);
ret = dtls1_send_hello_verify_request(s);
if ( ret <= 0) goto end;
s->d1->send_cookie = 0;
s->state=SSL3_ST_SW_FLUSH;
s->s3->tmp.next_state=SSL3_ST_SR_CLNT_HELLO_A;
@ -670,15 +664,13 @@ int dtls1_send_hello_verify_request(SSL *s)
*(p++) = s->version >> 8;
*(p++) = s->version & 0xFF;
if (s->ctx->app_gen_cookie_cb != NULL &&
s->ctx->app_gen_cookie_cb(s, s->d1->cookie,
&(s->d1->cookie_len)) == 0)
if (s->ctx->app_gen_cookie_cb == NULL ||
s->ctx->app_gen_cookie_cb(s, s->d1->cookie,
&(s->d1->cookie_len)) == 0)
{
SSLerr(SSL_F_DTLS1_SEND_HELLO_VERIFY_REQUEST,ERR_R_INTERNAL_ERROR);
return 0;
}
/* else the cookie is assumed to have
* been initialized by the application */
*(p++) = (unsigned char) s->d1->cookie_len;
memcpy(p, s->d1->cookie, s->d1->cookie_len);

2
ssl/dtls1.h
View File

@ -84,7 +84,7 @@ extern "C" {
#endif
/* lengths of messages */
#define DTLS1_COOKIE_LENGTH 32
#define DTLS1_COOKIE_LENGTH 256
#define DTLS1_RT_HEADER_LENGTH 13

35
ssl/s3_srvr.c
View File

@ -816,6 +816,21 @@ int ssl3_get_client_hello(SSL *s)
goto f_err;
}
/* If we require cookies and this ClientHello doesn't
* contain one, just return since we do not want to
* allocate any memory yet. So check cookie length...
*/
if (SSL_get_options(s) & SSL_OP_COOKIE_EXCHANGE)
{
unsigned int session_length, cookie_length;
session_length = *(p + SSL3_RANDOM_SIZE);
cookie_length = *(p + SSL3_RANDOM_SIZE + session_length + 1);
if (cookie_len == 0)
return 1;
}
/* load the client random */
memcpy(s->s3->client_random,p,SSL3_RANDOM_SIZE);
p+=SSL3_RANDOM_SIZE;
@ -855,23 +870,11 @@ int ssl3_get_client_hello(SSL *s)
p+=j;
if (s->version == DTLS1_VERSION)
if (s->version == DTLS1_VERSION || s->version == DTLS1_BAD_VER)
{
/* cookie stuff */
cookie_len = *(p++);
if ( (SSL_get_options(s) & SSL_OP_COOKIE_EXCHANGE) &&
s->d1->send_cookie == 0)
{
/* HelloVerifyMessage has already been sent */
if ( cookie_len != s->d1->cookie_len)
{
al = SSL_AD_HANDSHAKE_FAILURE;
SSLerr(SSL_F_SSL3_GET_CLIENT_HELLO, SSL_R_COOKIE_MISMATCH);
goto f_err;
}
}
/*
* The ClientHello may contain a cookie even if the
* HelloVerify message has not been sent--make sure that it
@ -886,7 +889,7 @@ int ssl3_get_client_hello(SSL *s)
}
/* verify the cookie if appropriate option is set. */
if ( (SSL_get_options(s) & SSL_OP_COOKIE_EXCHANGE) &&
if ((SSL_get_options(s) & SSL_OP_COOKIE_EXCHANGE) &&
cookie_len > 0)
{
memcpy(s->d1->rcvd_cookie, p, cookie_len);
@ -911,6 +914,8 @@ int ssl3_get_client_hello(SSL *s)
SSL_R_COOKIE_MISMATCH);
goto f_err;
}
ret = 2;
}
p += cookie_len;
@ -1185,7 +1190,7 @@ int ssl3_get_client_hello(SSL *s)
* s->tmp.new_cipher - the new cipher to use.
*/
ret=1;
if (ret < 0) ret=1;
if (0)
{
f_err:

8
ssl/t1_lib.c
View File

@ -1444,6 +1444,14 @@ int tls1_process_ticket(SSL *s, unsigned char *session_id, int len,
return 1;
if (p >= limit)
return -1;
/* Skip past DTLS cookie */
if (s->version == DTLS1_VERSION || s->version == DTLS1_BAD_VER)
{
i = *(p++);
p+= i;
if (p >= limit)
return -1;
}
/* Skip past cipher list */
n2s(p, i);
p+= i;