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[tls] Use asynchronous certificate validator
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Signed-off-by: Michael Brown <mcb30@ipxe.org>
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@mcb30
mcb30 committed May 8, 2012
1 parent 29dcb06 commit f19565f
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Showing 2 changed files with 120 additions and 48 deletions.
9 changes: 7 additions & 2 deletions src/include/ipxe/tls.h
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Expand Up @@ -237,15 +237,20 @@ struct tls_session {

/** Server certificate chain */
struct x509_chain *chain;
/** Certificate validator */
struct interface validator;

/** Client has finished security negotiation */
unsigned int client_finished;
/** Server has finished security negotiation */
unsigned int server_finished;

/** TX sequence number */
uint64_t tx_seq;
/** TX pending transmissions */
unsigned int tx_pending;
/** TX process */
struct process process;
/** TX ready for plaintext data */
int tx_ready;

/** RX sequence number */
uint64_t rx_seq;
Expand Down
159 changes: 113 additions & 46 deletions src/net/tls.c
View file
Expand Up @@ -43,6 +43,7 @@ FILE_LICENCE ( GPL2_OR_LATER );
#include <ipxe/x509.h>
#include <ipxe/clientcert.h>
#include <ipxe/rbg.h>
#include <ipxe/validator.h>
#include <ipxe/tls.h>

/* Disambiguate the various error causes */
Expand Down Expand Up @@ -93,6 +94,16 @@ static void tls_set_uint24 ( uint8_t field24[3], unsigned long value ) {
*field32 |= cpu_to_be32 ( value << 8 );
}

/**
* Determine if TLS session is ready for application data
*
* @v tls TLS session
* @ret is_ready TLS session is ready
*/
static int tls_ready ( struct tls_session *tls ) {
return ( tls->client_finished && tls->server_finished );
}

/******************************************************************************
*
* Hybrid MD5+SHA1 hash as used by TLSv1.1 and earlier
Expand Down Expand Up @@ -196,10 +207,11 @@ static void tls_close ( struct tls_session *tls, int rc ) {

/* Remove process */
process_del ( &tls->process );
/* Close ciphertext and plaintext streams */

/* Close all interfaces */
intf_shutdown ( &tls->cipherstream, rc );
intf_shutdown ( &tls->plainstream, rc );
intf_shutdown ( &tls->validator, rc );
}

/******************************************************************************
Expand Down Expand Up @@ -1111,7 +1123,9 @@ static int tls_send_finished ( struct tls_session *tls ) {
uint8_t verify_data[12];
} __attribute__ (( packed )) finished;
uint8_t digest_out[ digest->digestsize ];
int rc;

/* Construct record */
memset ( &finished, 0, sizeof ( finished ) );
finished.type_length = ( cpu_to_le32 ( TLS_FINISHED ) |
htonl ( sizeof ( finished ) -
Expand All @@ -1121,7 +1135,15 @@ static int tls_send_finished ( struct tls_session *tls ) {
finished.verify_data, sizeof ( finished.verify_data ),
"client finished", digest_out, sizeof ( digest_out ) );

return tls_send_handshake ( tls, &finished, sizeof ( finished ) );
/* Transmit record */
if ( ( rc = tls_send_handshake ( tls, &finished,
sizeof ( finished ) ) ) != 0 )
return rc;

/* Mark client as finished */
tls->client_finished = 1;

return 0;
}

/**
Expand Down Expand Up @@ -1354,10 +1376,6 @@ static int tls_new_certificate ( struct tls_session *tls,
} __attribute__ (( packed )) *certificate = data;
size_t certificates_len = tls_uint24 ( certificate->length );
const void *end = ( certificate->certificates + certificates_len );
struct tls_cipherspec *cipherspec = &tls->tx_cipherspec_pending;
struct pubkey_algorithm *pubkey = cipherspec->suite->pubkey;
struct x509_certificate *cert;
time_t now;
int rc;

/* Sanity check */
Expand All @@ -1373,35 +1391,6 @@ static int tls_new_certificate ( struct tls_session *tls,
certificates_len ) ) != 0 )
return rc;

/* Validate certificate chain */
now = time ( NULL );
if ( ( rc = x509_validate_chain ( tls->chain, now, NULL ) ) != 0 ) {
DBGC ( tls, "TLS %p could not validate certificate chain: %s\n",
tls, strerror ( rc ) );
return rc;
}

/* Extract first certificate */
cert = x509_first ( tls->chain );
assert ( cert != NULL );

/* Verify server name */
if ( ( cert->subject.name == NULL ) ||
( strcmp ( cert->subject.name, tls->name ) != 0 ) ) {
DBGC ( tls, "TLS %p server name incorrect (expected %s, got "
"%s)\n", tls, tls->name, cert->subject.name );
return -EACCES_WRONG_NAME;
}

/* Initialise public key algorithm */
if ( ( rc = pubkey_init ( pubkey, cipherspec->pubkey_ctx,
cert->subject.public_key.raw.data,
cert->subject.public_key.raw.len ) ) != 0 ) {
DBGC ( tls, "TLS %p cannot initialise public key: %s\n",
tls, strerror ( rc ) );
return rc;
}

return 0;
}

Expand Down Expand Up @@ -1442,6 +1431,7 @@ static int tls_new_server_hello_done ( struct tls_session *tls,
char next[0];
} __attribute__ (( packed )) *hello_done = data;
const void *end = hello_done->next;
int rc;

/* Sanity check */
if ( end != ( data + len ) ) {
Expand All @@ -1451,11 +1441,12 @@ static int tls_new_server_hello_done ( struct tls_session *tls,
return -EINVAL;
}

/* Schedule Client Key Exchange, Change Cipher, and Finished */
tls->tx_pending |= ( TLS_TX_CLIENT_KEY_EXCHANGE |
TLS_TX_CHANGE_CIPHER |
TLS_TX_FINISHED );
tls_tx_resume ( tls );
/* Begin certificate validation */
if ( ( rc = create_validator ( &tls->validator, tls->chain ) ) != 0 ) {
DBGC ( tls, "TLS %p could not start certificate validation: "
"%s\n", tls, strerror ( rc ) );
return rc;
}

return 0;
}
Expand Down Expand Up @@ -1497,8 +1488,8 @@ static int tls_new_finished ( struct tls_session *tls,
return -EPERM;
}

/* Mark session as ready to transmit plaintext data */
tls->tx_ready = 1;
/* Mark server as finished */
tls->server_finished = 1;

/* Send notification of a window change */
xfer_window_changed ( &tls->plainstream );
Expand Down Expand Up @@ -1601,6 +1592,8 @@ static int tls_new_record ( struct tls_session *tls, unsigned int type,
case TLS_TYPE_HANDSHAKE:
return tls_new_handshake ( tls, data, len );
case TLS_TYPE_DATA:
if ( ! tls_ready ( tls ) )
return -ENOTCONN;
return xfer_deliver_raw ( &tls->plainstream, data, len );
default:
/* RFC4346 says that we should just ignore unknown
Expand Down Expand Up @@ -2015,7 +2008,7 @@ static int tls_new_ciphertext ( struct tls_session *tls,
static size_t tls_plainstream_window ( struct tls_session *tls ) {

/* Block window unless we are ready to accept data */
if ( ! tls->tx_ready )
if ( ! tls_ready ( tls ) )
return 0;

return xfer_window ( &tls->cipherstream );
Expand All @@ -2035,7 +2028,7 @@ static int tls_plainstream_deliver ( struct tls_session *tls,
int rc;

/* Refuse unless we are ready to accept data */
if ( ! tls->tx_ready ) {
if ( ! tls_ready ( tls ) ) {
rc = -ENOTCONN;
goto done;
}
Expand Down Expand Up @@ -2192,6 +2185,79 @@ static struct interface_descriptor tls_cipherstream_desc =
INTF_DESC_PASSTHRU ( struct tls_session, cipherstream,
tls_cipherstream_ops, plainstream );

/******************************************************************************
*
* Certificate validator
*
******************************************************************************
*/

/**
* Handle certificate validation completion
*
* @v tls TLS session
* @v rc Reason for completion
*/
static void tls_validator_done ( struct tls_session *tls, int rc ) {
struct tls_cipherspec *cipherspec = &tls->tx_cipherspec_pending;
struct pubkey_algorithm *pubkey = cipherspec->suite->pubkey;
struct x509_certificate *cert;

/* Close validator interface */
intf_restart ( &tls->validator, rc );

/* Check for validation failure */
if ( rc != 0 ) {
DBGC ( tls, "TLS %p certificate validation failed: %s\n",
tls, strerror ( rc ) );
goto err;
}
DBGC ( tls, "TLS %p certificate validation succeeded\n", tls );

/* Extract first certificate */
cert = x509_first ( tls->chain );
assert ( cert != NULL );

/* Verify server name */
if ( ( cert->subject.name == NULL ) ||
( strcmp ( cert->subject.name, tls->name ) != 0 ) ) {
DBGC ( tls, "TLS %p server name incorrect (expected %s, got "
"%s)\n", tls, tls->name, cert->subject.name );
rc = -EACCES_WRONG_NAME;
goto err;
}

/* Initialise public key algorithm */
if ( ( rc = pubkey_init ( pubkey, cipherspec->pubkey_ctx,
cert->subject.public_key.raw.data,
cert->subject.public_key.raw.len ) ) != 0 ) {
DBGC ( tls, "TLS %p cannot initialise public key: %s\n",
tls, strerror ( rc ) );
goto err;
}

/* Schedule Client Key Exchange, Change Cipher, and Finished */
tls->tx_pending |= ( TLS_TX_CLIENT_KEY_EXCHANGE |
TLS_TX_CHANGE_CIPHER |
TLS_TX_FINISHED );
tls_tx_resume ( tls );

return;

err:
tls_close ( tls, rc );
return;
}

/** TLS certificate validator interface operations */
static struct interface_operation tls_validator_ops[] = {
INTF_OP ( intf_close, struct tls_session *, tls_validator_done ),
};

/** TLS certificate validator interface descriptor */
static struct interface_descriptor tls_validator_desc =
INTF_DESC ( struct tls_session, validator, tls_validator_ops );

/******************************************************************************
*
* Controlling process
Expand Down Expand Up @@ -2307,6 +2373,8 @@ int add_tls ( struct interface *xfer, const char *name,
tls->name = name;
intf_init ( &tls->plainstream, &tls_plainstream_desc, &tls->refcnt );
intf_init ( &tls->cipherstream, &tls_cipherstream_desc, &tls->refcnt );
intf_init ( &tls->validator, &tls_validator_desc, &tls->refcnt );
process_init ( &tls->process, &tls_process_desc, &tls->refcnt );
tls->version = TLS_VERSION_TLS_1_2;
tls_clear_cipher ( tls, &tls->tx_cipherspec );
tls_clear_cipher ( tls, &tls->tx_cipherspec_pending );
Expand All @@ -2327,7 +2395,6 @@ int add_tls ( struct interface *xfer, const char *name,
tls->handshake_digest = &sha256_algorithm;
tls->handshake_ctx = tls->handshake_sha256_ctx;
tls->tx_pending = TLS_TX_CLIENT_HELLO;
process_init ( &tls->process, &tls_process_desc, &tls->refcnt );

/* Attach to parent interface, mortalise self, and return */
intf_plug_plug ( &tls->plainstream, xfer );
Expand Down

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