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4ad3c73b30
ipxe/src/net/tls.c
Michael Brown 05dcb07cb2 [tls] Avoid potential out-of-bound reads in length fields 
Many TLS records contain variable-length fields.  We currently
validate the overall record length, but do so only after reading the
length of the variable-length field.  If the record is too short to
even contain the length field, then we may read uninitialised data
from beyond the end of the record.

This is harmless in practice (since the subsequent overall record
length check would fail regardless of the value read from the
uninitialised length field), but causes warnings from some analysis
tools.

Fix by validating that the overall record length is sufficient to
contain the length field before reading from the length field.

Signed-off-by: Michael Brown <mcb30@ipxe.org>
2016-03-11 16:09:40 +00:00

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/*
* Copyright (C) 2007 Michael Brown <mbrown@fensystems.co.uk>.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of the
* License, or any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301, USA.
*/
FILE_LICENCE ( GPL2_OR_LATER );
/**
* @file
*
* Transport Layer Security Protocol
*/
#include <stdint.h>
#include <stdlib.h>
#include <stdarg.h>
#include <string.h>
#include <time.h>
#include <errno.h>
#include <byteswap.h>
#include <ipxe/pending.h>
#include <ipxe/hmac.h>
#include <ipxe/md5.h>
#include <ipxe/sha1.h>
#include <ipxe/sha256.h>
#include <ipxe/aes.h>
#include <ipxe/rsa.h>
#include <ipxe/iobuf.h>
#include <ipxe/xfer.h>
#include <ipxe/open.h>
#include <ipxe/x509.h>
#include <ipxe/privkey.h>
#include <ipxe/certstore.h>
#include <ipxe/rbg.h>
#include <ipxe/validator.h>
#include <ipxe/tls.h>
/* Disambiguate the various error causes */
#define EINVAL_CHANGE_CIPHER __einfo_error ( EINFO_EINVAL_CHANGE_CIPHER )
#define EINFO_EINVAL_CHANGE_CIPHER \
__einfo_uniqify ( EINFO_EINVAL, 0x01, \
"Invalid Change Cipher record" )
#define EINVAL_ALERT __einfo_error ( EINFO_EINVAL_ALERT )
#define EINFO_EINVAL_ALERT \
__einfo_uniqify ( EINFO_EINVAL, 0x02, \
"Invalid Alert record" )
#define EINVAL_HELLO __einfo_error ( EINFO_EINVAL_HELLO )
#define EINFO_EINVAL_HELLO \
__einfo_uniqify ( EINFO_EINVAL, 0x03, \
"Invalid Server Hello record" )
#define EINVAL_CERTIFICATE __einfo_error ( EINFO_EINVAL_CERTIFICATE )
#define EINFO_EINVAL_CERTIFICATE \
__einfo_uniqify ( EINFO_EINVAL, 0x04, \
"Invalid Certificate" )
#define EINVAL_CERTIFICATES __einfo_error ( EINFO_EINVAL_CERTIFICATES )
#define EINFO_EINVAL_CERTIFICATES \
__einfo_uniqify ( EINFO_EINVAL, 0x05, \
"Invalid Server Certificate record" )
#define EINVAL_HELLO_DONE __einfo_error ( EINFO_EINVAL_HELLO_DONE )
#define EINFO_EINVAL_HELLO_DONE \
__einfo_uniqify ( EINFO_EINVAL, 0x06, \
"Invalid Server Hello Done record" )
#define EINVAL_FINISHED __einfo_error ( EINFO_EINVAL_FINISHED )
#define EINFO_EINVAL_FINISHED \
__einfo_uniqify ( EINFO_EINVAL, 0x07, \
"Invalid Server Finished record" )
#define EINVAL_HANDSHAKE __einfo_error ( EINFO_EINVAL_HANDSHAKE )
#define EINFO_EINVAL_HANDSHAKE \
__einfo_uniqify ( EINFO_EINVAL, 0x08, \
"Invalid Handshake record" )
#define EINVAL_STREAM __einfo_error ( EINFO_EINVAL_STREAM )
#define EINFO_EINVAL_STREAM \
__einfo_uniqify ( EINFO_EINVAL, 0x09, \
"Invalid stream-ciphered record" )
#define EINVAL_BLOCK __einfo_error ( EINFO_EINVAL_BLOCK )
#define EINFO_EINVAL_BLOCK \
__einfo_uniqify ( EINFO_EINVAL, 0x0a, \
"Invalid block-ciphered record" )
#define EINVAL_PADDING __einfo_error ( EINFO_EINVAL_PADDING )
#define EINFO_EINVAL_PADDING \
__einfo_uniqify ( EINFO_EINVAL, 0x0b, \
"Invalid block padding" )
#define EINVAL_RX_STATE __einfo_error ( EINFO_EINVAL_RX_STATE )
#define EINFO_EINVAL_RX_STATE \
__einfo_uniqify ( EINFO_EINVAL, 0x0c, \
"Invalid receive state" )
#define EINVAL_MAC __einfo_error ( EINFO_EINVAL_MAC )
#define EINFO_EINVAL_MAC \
__einfo_uniqify ( EINFO_EINVAL, 0x0d, \
"Invalid MAC" )
#define EIO_ALERT __einfo_error ( EINFO_EIO_ALERT )
#define EINFO_EIO_ALERT \
__einfo_uniqify ( EINFO_EINVAL, 0x01, \
"Unknown alert level" )
#define ENOMEM_CONTEXT __einfo_error ( EINFO_ENOMEM_CONTEXT )
#define EINFO_ENOMEM_CONTEXT \
__einfo_uniqify ( EINFO_ENOMEM, 0x01, \
"Not enough space for crypto context" )
#define ENOMEM_CERTIFICATE __einfo_error ( EINFO_ENOMEM_CERTIFICATE )
#define EINFO_ENOMEM_CERTIFICATE \
__einfo_uniqify ( EINFO_ENOMEM, 0x02, \
"Not enough space for certificate" )
#define ENOMEM_CHAIN __einfo_error ( EINFO_ENOMEM_CHAIN )
#define EINFO_ENOMEM_CHAIN \
__einfo_uniqify ( EINFO_ENOMEM, 0x03, \
"Not enough space for certificate chain" )
#define ENOMEM_TX_PLAINTEXT __einfo_error ( EINFO_ENOMEM_TX_PLAINTEXT )
#define EINFO_ENOMEM_TX_PLAINTEXT \
__einfo_uniqify ( EINFO_ENOMEM, 0x04, \
"Not enough space for transmitted plaintext" )
#define ENOMEM_TX_CIPHERTEXT __einfo_error ( EINFO_ENOMEM_TX_CIPHERTEXT )
#define EINFO_ENOMEM_TX_CIPHERTEXT \
__einfo_uniqify ( EINFO_ENOMEM, 0x05, \
"Not enough space for transmitted ciphertext" )
#define ENOMEM_RX_DATA __einfo_error ( EINFO_ENOMEM_RX_DATA )
#define EINFO_ENOMEM_RX_DATA \
__einfo_uniqify ( EINFO_ENOMEM, 0x07, \
"Not enough space for received data" )
#define ENOMEM_RX_CONCAT __einfo_error ( EINFO_ENOMEM_RX_CONCAT )
#define EINFO_ENOMEM_RX_CONCAT \
__einfo_uniqify ( EINFO_ENOMEM, 0x08, \
"Not enough space to concatenate received data" )
#define ENOTSUP_CIPHER __einfo_error ( EINFO_ENOTSUP_CIPHER )
#define EINFO_ENOTSUP_CIPHER \
__einfo_uniqify ( EINFO_ENOTSUP, 0x01, \
"Unsupported cipher" )
#define ENOTSUP_NULL __einfo_error ( EINFO_ENOTSUP_NULL )
#define EINFO_ENOTSUP_NULL \
__einfo_uniqify ( EINFO_ENOTSUP, 0x02, \
"Refusing to use null cipher" )
#define ENOTSUP_SIG_HASH __einfo_error ( EINFO_ENOTSUP_SIG_HASH )
#define EINFO_ENOTSUP_SIG_HASH \
__einfo_uniqify ( EINFO_ENOTSUP, 0x03, \
"Unsupported signature and hash algorithm" )
#define ENOTSUP_VERSION __einfo_error ( EINFO_ENOTSUP_VERSION )
#define EINFO_ENOTSUP_VERSION \
__einfo_uniqify ( EINFO_ENOTSUP, 0x04, \
"Unsupported protocol version" )
#define EPERM_ALERT __einfo_error ( EINFO_EPERM_ALERT )
#define EINFO_EPERM_ALERT \
__einfo_uniqify ( EINFO_EPERM, 0x01, \
"Received fatal alert" )
#define EPERM_VERIFY __einfo_error ( EINFO_EPERM_VERIFY )
#define EINFO_EPERM_VERIFY \
__einfo_uniqify ( EINFO_EPERM, 0x02, \
"Handshake verification failed" )
#define EPERM_CLIENT_CERT __einfo_error ( EINFO_EPERM_CLIENT_CERT )
#define EINFO_EPERM_CLIENT_CERT \
__einfo_uniqify ( EINFO_EPERM, 0x03, \
"No suitable client certificate available" )
#define EPROTO_VERSION __einfo_error ( EINFO_EPROTO_VERSION )
#define EINFO_EPROTO_VERSION \
__einfo_uniqify ( EINFO_EPROTO, 0x01, \
"Illegal protocol version upgrade" )
static int tls_send_plaintext ( struct tls_session *tls, unsigned int type,
const void *data, size_t len );
static void tls_clear_cipher ( struct tls_session *tls,
struct tls_cipherspec *cipherspec );
/******************************************************************************
*
* Utility functions
*
******************************************************************************
*/
/** A TLS 24-bit integer
*
* TLS uses 24-bit integers in several places, which are awkward to
* parse in C.
*/
typedef struct {
/** High byte */
uint8_t high;
/** Low word */
uint16_t low;
} __attribute__ (( packed )) tls24_t;
/**
* Extract 24-bit field value
*
* @v field24 24-bit field
* @ret value Field value
*
*/
static inline __attribute__ (( always_inline )) unsigned long
tls_uint24 ( const tls24_t *field24 ) {
return ( ( field24->high << 16 ) | be16_to_cpu ( field24->low ) );
}
/**
* Set 24-bit field value
*
* @v field24 24-bit field
* @v value Field value
*/
static void tls_set_uint24 ( tls24_t *field24, unsigned long value ) {
field24->high = ( value >> 16 );
field24->low = cpu_to_be16 ( value );
}
/**
* 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 ( ( ! is_pending ( &tls->client_negotiation ) ) &&
( ! is_pending ( &tls->server_negotiation ) ) );
}
/******************************************************************************
*
* Hybrid MD5+SHA1 hash as used by TLSv1.1 and earlier
*
******************************************************************************
*/
/**
* Initialise MD5+SHA1 algorithm
*
* @v ctx MD5+SHA1 context
*/
static void md5_sha1_init ( void *ctx ) {
struct md5_sha1_context *context = ctx;
digest_init ( &md5_algorithm, context->md5 );
digest_init ( &sha1_algorithm, context->sha1 );
}
/**
* Accumulate data with MD5+SHA1 algorithm
*
* @v ctx MD5+SHA1 context
* @v data Data
* @v len Length of data
*/
static void md5_sha1_update ( void *ctx, const void *data, size_t len ) {
struct md5_sha1_context *context = ctx;
digest_update ( &md5_algorithm, context->md5, data, len );
digest_update ( &sha1_algorithm, context->sha1, data, len );
}
/**
* Generate MD5+SHA1 digest
*
* @v ctx MD5+SHA1 context
* @v out Output buffer
*/
static void md5_sha1_final ( void *ctx, void *out ) {
struct md5_sha1_context *context = ctx;
struct md5_sha1_digest *digest = out;
digest_final ( &md5_algorithm, context->md5, digest->md5 );
digest_final ( &sha1_algorithm, context->sha1, digest->sha1 );
}
/** Hybrid MD5+SHA1 digest algorithm */
static struct digest_algorithm md5_sha1_algorithm = {
.name = "md5+sha1",
.ctxsize = sizeof ( struct md5_sha1_context ),
.blocksize = 0, /* Not applicable */
.digestsize = sizeof ( struct md5_sha1_digest ),
.init = md5_sha1_init,
.update = md5_sha1_update,
.final = md5_sha1_final,
};
/** RSA digestInfo prefix for MD5+SHA1 algorithm */
struct rsa_digestinfo_prefix rsa_md5_sha1_prefix __rsa_digestinfo_prefix = {
.digest = &md5_sha1_algorithm,
.data = NULL, /* MD5+SHA1 signatures have no digestInfo */
.len = 0,
};
/******************************************************************************
*
* Cleanup functions
*
******************************************************************************
*/
/**
* Free TLS session
*
* @v refcnt Reference counter
*/
static void free_tls ( struct refcnt *refcnt ) {
struct tls_session *tls =
container_of ( refcnt, struct tls_session, refcnt );
struct io_buffer *iobuf;
struct io_buffer *tmp;
/* Free dynamically-allocated resources */
tls_clear_cipher ( tls, &tls->tx_cipherspec );
tls_clear_cipher ( tls, &tls->tx_cipherspec_pending );
tls_clear_cipher ( tls, &tls->rx_cipherspec );
tls_clear_cipher ( tls, &tls->rx_cipherspec_pending );
list_for_each_entry_safe ( iobuf, tmp, &tls->rx_data, list ) {
list_del ( &iobuf->list );
free_iob ( iobuf );
}
x509_put ( tls->cert );
x509_chain_put ( tls->chain );
/* Free TLS structure itself */
free ( tls );
}
/**
* Finish with TLS session
*
* @v tls TLS session
* @v rc Status code
*/
static void tls_close ( struct tls_session *tls, int rc ) {
/* Remove pending operations, if applicable */
pending_put ( &tls->client_negotiation );
pending_put ( &tls->server_negotiation );
/* Remove process */
process_del ( &tls->process );
/* Close all interfaces */
intf_shutdown ( &tls->cipherstream, rc );
intf_shutdown ( &tls->plainstream, rc );
intf_shutdown ( &tls->validator, rc );
}
/******************************************************************************
*
* Random number generation
*
******************************************************************************
*/
/**
* Generate random data
*
* @v tls TLS session
* @v data Buffer to fill
* @v len Length of buffer
* @ret rc Return status code
*/
static int tls_generate_random ( struct tls_session *tls,
void *data, size_t len ) {
int rc;
/* Generate random bits with no additional input and without
* prediction resistance
*/
if ( ( rc = rbg_generate ( NULL, 0, 0, data, len ) ) != 0 ) {
DBGC ( tls, "TLS %p could not generate random data: %s\n",
tls, strerror ( rc ) );
return rc;
}
return 0;
}
/**
* Update HMAC with a list of ( data, len ) pairs
*
* @v digest Hash function to use
* @v digest_ctx Digest context
* @v args ( data, len ) pairs of data, terminated by NULL
*/
static void tls_hmac_update_va ( struct digest_algorithm *digest,
void *digest_ctx, va_list args ) {
void *data;
size_t len;
while ( ( data = va_arg ( args, void * ) ) ) {
len = va_arg ( args, size_t );
hmac_update ( digest, digest_ctx, data, len );
}
}
/**
* Generate secure pseudo-random data using a single hash function
*
* @v tls TLS session
* @v digest Hash function to use
* @v secret Secret
* @v secret_len Length of secret
* @v out Output buffer
* @v out_len Length of output buffer
* @v seeds ( data, len ) pairs of seed data, terminated by NULL
*/
static void tls_p_hash_va ( struct tls_session *tls,
struct digest_algorithm *digest,
void *secret, size_t secret_len,
void *out, size_t out_len,
va_list seeds ) {
uint8_t secret_copy[secret_len];
uint8_t digest_ctx[digest->ctxsize];
uint8_t digest_ctx_partial[digest->ctxsize];
uint8_t a[digest->digestsize];
uint8_t out_tmp[digest->digestsize];
size_t frag_len = digest->digestsize;
va_list tmp;
/* Copy the secret, in case HMAC modifies it */
memcpy ( secret_copy, secret, secret_len );
secret = secret_copy;
DBGC2 ( tls, "TLS %p %s secret:\n", tls, digest->name );
DBGC2_HD ( tls, secret, secret_len );
/* Calculate A(1) */
hmac_init ( digest, digest_ctx, secret, &secret_len );
va_copy ( tmp, seeds );
tls_hmac_update_va ( digest, digest_ctx, tmp );
va_end ( tmp );
hmac_final ( digest, digest_ctx, secret, &secret_len, a );
DBGC2 ( tls, "TLS %p %s A(1):\n", tls, digest->name );
DBGC2_HD ( tls, &a, sizeof ( a ) );
/* Generate as much data as required */
while ( out_len ) {
/* Calculate output portion */
hmac_init ( digest, digest_ctx, secret, &secret_len );
hmac_update ( digest, digest_ctx, a, sizeof ( a ) );
memcpy ( digest_ctx_partial, digest_ctx, digest->ctxsize );
va_copy ( tmp, seeds );
tls_hmac_update_va ( digest, digest_ctx, tmp );
va_end ( tmp );
hmac_final ( digest, digest_ctx,
secret, &secret_len, out_tmp );
/* Copy output */
if ( frag_len > out_len )
frag_len = out_len;
memcpy ( out, out_tmp, frag_len );
DBGC2 ( tls, "TLS %p %s output:\n", tls, digest->name );
DBGC2_HD ( tls, out, frag_len );
/* Calculate A(i) */
hmac_final ( digest, digest_ctx_partial,
secret, &secret_len, a );
DBGC2 ( tls, "TLS %p %s A(n):\n", tls, digest->name );
DBGC2_HD ( tls, &a, sizeof ( a ) );
out += frag_len;
out_len -= frag_len;
}
}
/**
* Generate secure pseudo-random data
*
* @v tls TLS session
* @v secret Secret
* @v secret_len Length of secret
* @v out Output buffer
* @v out_len Length of output buffer
* @v ... ( data, len ) pairs of seed data, terminated by NULL
*/
static void tls_prf ( struct tls_session *tls, void *secret, size_t secret_len,
void *out, size_t out_len, ... ) {
va_list seeds;
va_list tmp;
size_t subsecret_len;
void *md5_secret;
void *sha1_secret;
uint8_t buf[out_len];
unsigned int i;
va_start ( seeds, out_len );
if ( tls->version >= TLS_VERSION_TLS_1_2 ) {
/* Use P_SHA256 for TLSv1.2 and later */
tls_p_hash_va ( tls, &sha256_algorithm, secret, secret_len,
out, out_len, seeds );
} else {
/* Use combination of P_MD5 and P_SHA-1 for TLSv1.1
* and earlier
*/
/* Split secret into two, with an overlap of up to one byte */
subsecret_len = ( ( secret_len + 1 ) / 2 );
md5_secret = secret;
sha1_secret = ( secret + secret_len - subsecret_len );
/* Calculate MD5 portion */
va_copy ( tmp, seeds );
tls_p_hash_va ( tls, &md5_algorithm, md5_secret,
subsecret_len, out, out_len, seeds );
va_end ( tmp );
/* Calculate SHA1 portion */
va_copy ( tmp, seeds );
tls_p_hash_va ( tls, &sha1_algorithm, sha1_secret,
subsecret_len, buf, out_len, seeds );
va_end ( tmp );
/* XOR the two portions together into the final output buffer */
for ( i = 0 ; i < out_len ; i++ )
*( ( uint8_t * ) out + i ) ^= buf[i];
}
va_end ( seeds );
}
/**
* Generate secure pseudo-random data
*
* @v secret Secret
* @v secret_len Length of secret
* @v out Output buffer
* @v out_len Length of output buffer
* @v label String literal label
* @v ... ( data, len ) pairs of seed data
*/
#define tls_prf_label( tls, secret, secret_len, out, out_len, label, ... ) \
tls_prf ( (tls), (secret), (secret_len), (out), (out_len), \
label, ( sizeof ( label ) - 1 ), __VA_ARGS__, NULL )
/******************************************************************************
*
* Secret management
*
******************************************************************************
*/
/**
* Generate master secret
*
* @v tls TLS session
*
* The pre-master secret and the client and server random values must
* already be known.
*/
static void tls_generate_master_secret ( struct tls_session *tls ) {
DBGC ( tls, "TLS %p pre-master-secret:\n", tls );
DBGC_HD ( tls, &tls->pre_master_secret,
sizeof ( tls->pre_master_secret ) );
DBGC ( tls, "TLS %p client random bytes:\n", tls );
DBGC_HD ( tls, &tls->client_random, sizeof ( tls->client_random ) );
DBGC ( tls, "TLS %p server random bytes:\n", tls );
DBGC_HD ( tls, &tls->server_random, sizeof ( tls->server_random ) );
tls_prf_label ( tls, &tls->pre_master_secret,
sizeof ( tls->pre_master_secret ),
&tls->master_secret, sizeof ( tls->master_secret ),
"master secret",
&tls->client_random, sizeof ( tls->client_random ),
&tls->server_random, sizeof ( tls->server_random ) );
DBGC ( tls, "TLS %p generated master secret:\n", tls );
DBGC_HD ( tls, &tls->master_secret, sizeof ( tls->master_secret ) );
}
/**
* Generate key material
*
* @v tls TLS session
*
* The master secret must already be known.
*/
static int tls_generate_keys ( struct tls_session *tls ) {
struct tls_cipherspec *tx_cipherspec = &tls->tx_cipherspec_pending;
struct tls_cipherspec *rx_cipherspec = &tls->rx_cipherspec_pending;
size_t hash_size = tx_cipherspec->suite->digest->digestsize;
size_t key_size = tx_cipherspec->suite->key_len;
size_t iv_size = tx_cipherspec->suite->cipher->blocksize;
size_t total = ( 2 * ( hash_size + key_size + iv_size ) );
uint8_t key_block[total];
uint8_t *key;
int rc;
/* Generate key block */
tls_prf_label ( tls, &tls->master_secret, sizeof ( tls->master_secret ),
key_block, sizeof ( key_block ), "key expansion",
&tls->server_random, sizeof ( tls->server_random ),
&tls->client_random, sizeof ( tls->client_random ) );
/* Split key block into portions */
key = key_block;
/* TX MAC secret */
memcpy ( tx_cipherspec->mac_secret, key, hash_size );
DBGC ( tls, "TLS %p TX MAC secret:\n", tls );
DBGC_HD ( tls, key, hash_size );
key += hash_size;
/* RX MAC secret */
memcpy ( rx_cipherspec->mac_secret, key, hash_size );
DBGC ( tls, "TLS %p RX MAC secret:\n", tls );
DBGC_HD ( tls, key, hash_size );
key += hash_size;
/* TX key */
if ( ( rc = cipher_setkey ( tx_cipherspec->suite->cipher,
tx_cipherspec->cipher_ctx,
key, key_size ) ) != 0 ) {
DBGC ( tls, "TLS %p could not set TX key: %s\n",
tls, strerror ( rc ) );
return rc;
}
DBGC ( tls, "TLS %p TX key:\n", tls );
DBGC_HD ( tls, key, key_size );
key += key_size;
/* RX key */
if ( ( rc = cipher_setkey ( rx_cipherspec->suite->cipher,
rx_cipherspec->cipher_ctx,
key, key_size ) ) != 0 ) {
DBGC ( tls, "TLS %p could not set TX key: %s\n",
tls, strerror ( rc ) );
return rc;
}
DBGC ( tls, "TLS %p RX key:\n", tls );
DBGC_HD ( tls, key, key_size );
key += key_size;
/* TX initialisation vector */
cipher_setiv ( tx_cipherspec->suite->cipher,
tx_cipherspec->cipher_ctx, key );
DBGC ( tls, "TLS %p TX IV:\n", tls );
DBGC_HD ( tls, key, iv_size );
key += iv_size;
/* RX initialisation vector */
cipher_setiv ( rx_cipherspec->suite->cipher,
rx_cipherspec->cipher_ctx, key );
DBGC ( tls, "TLS %p RX IV:\n", tls );
DBGC_HD ( tls, key, iv_size );
key += iv_size;
assert ( ( key_block + total ) == key );
return 0;
}
/******************************************************************************
*
* Cipher suite management
*
******************************************************************************
*/
/** Null cipher suite */
struct tls_cipher_suite tls_cipher_suite_null = {
.pubkey = &pubkey_null,
.cipher = &cipher_null,
.digest = &digest_null,
};
/** Number of supported cipher suites */
#define TLS_NUM_CIPHER_SUITES table_num_entries ( TLS_CIPHER_SUITES )
/**
* Identify cipher suite
*
* @v cipher_suite Cipher suite specification
* @ret suite Cipher suite, or NULL
*/
static struct tls_cipher_suite *
tls_find_cipher_suite ( unsigned int cipher_suite ) {
struct tls_cipher_suite *suite;
/* Identify cipher suite */
for_each_table_entry ( suite, TLS_CIPHER_SUITES ) {
if ( suite->code == cipher_suite )
return suite;
}
return NULL;
}
/**
* Clear cipher suite
*
* @v cipherspec TLS cipher specification
*/
static void tls_clear_cipher ( struct tls_session *tls __unused,
struct tls_cipherspec *cipherspec ) {
if ( cipherspec->suite ) {
pubkey_final ( cipherspec->suite->pubkey,
cipherspec->pubkey_ctx );
}
free ( cipherspec->dynamic );
memset ( cipherspec, 0, sizeof ( *cipherspec ) );
cipherspec->suite = &tls_cipher_suite_null;
}
/**
* Set cipher suite
*
* @v tls TLS session
* @v cipherspec TLS cipher specification
* @v suite Cipher suite
* @ret rc Return status code
*/
static int tls_set_cipher ( struct tls_session *tls,
struct tls_cipherspec *cipherspec,
struct tls_cipher_suite *suite ) {
struct pubkey_algorithm *pubkey = suite->pubkey;
struct cipher_algorithm *cipher = suite->cipher;
struct digest_algorithm *digest = suite->digest;
size_t total;
void *dynamic;
/* Clear out old cipher contents, if any */
tls_clear_cipher ( tls, cipherspec );
/* Allocate dynamic storage */
total = ( pubkey->ctxsize + 2 * cipher->ctxsize + digest->digestsize );
dynamic = zalloc ( total );
if ( ! dynamic ) {
DBGC ( tls, "TLS %p could not allocate %zd bytes for crypto "
"context\n", tls, total );
return -ENOMEM_CONTEXT;
}
/* Assign storage */
cipherspec->dynamic = dynamic;
cipherspec->pubkey_ctx = dynamic; dynamic += pubkey->ctxsize;
cipherspec->cipher_ctx = dynamic; dynamic += cipher->ctxsize;
cipherspec->cipher_next_ctx = dynamic; dynamic += cipher->ctxsize;
cipherspec->mac_secret = dynamic; dynamic += digest->digestsize;
assert ( ( cipherspec->dynamic + total ) == dynamic );
/* Store parameters */
cipherspec->suite = suite;
return 0;
}
/**
* Select next cipher suite
*
* @v tls TLS session
* @v cipher_suite Cipher suite specification
* @ret rc Return status code
*/
static int tls_select_cipher ( struct tls_session *tls,
unsigned int cipher_suite ) {
struct tls_cipher_suite *suite;
int rc;
/* Identify cipher suite */
suite = tls_find_cipher_suite ( cipher_suite );
if ( ! suite ) {
DBGC ( tls, "TLS %p does not support cipher %04x\n",
tls, ntohs ( cipher_suite ) );
return -ENOTSUP_CIPHER;
}
/* Set ciphers */
if ( ( rc = tls_set_cipher ( tls, &tls->tx_cipherspec_pending,
suite ) ) != 0 )
return rc;
if ( ( rc = tls_set_cipher ( tls, &tls->rx_cipherspec_pending,
suite ) ) != 0 )
return rc;
DBGC ( tls, "TLS %p selected %s-%s-%d-%s\n", tls, suite->pubkey->name,
suite->cipher->name, ( suite->key_len * 8 ),
suite->digest->name );
return 0;
}
/**
* Activate next cipher suite
*
* @v tls TLS session
* @v pending Pending cipher specification
* @v active Active cipher specification to replace
* @ret rc Return status code
*/
static int tls_change_cipher ( struct tls_session *tls,
struct tls_cipherspec *pending,
struct tls_cipherspec *active ) {
/* Sanity check */
if ( pending->suite == &tls_cipher_suite_null ) {
DBGC ( tls, "TLS %p refusing to use null cipher\n", tls );
return -ENOTSUP_NULL;
}
tls_clear_cipher ( tls, active );
memswap ( active, pending, sizeof ( *active ) );
return 0;
}
/******************************************************************************
*
* Signature and hash algorithms
*
******************************************************************************
*/
/** Number of supported signature and hash algorithms */
#define TLS_NUM_SIG_HASH_ALGORITHMS \
table_num_entries ( TLS_SIG_HASH_ALGORITHMS )
/**
* Find TLS signature and hash algorithm
*
* @v pubkey Public-key algorithm
* @v digest Digest algorithm
* @ret sig_hash Signature and hash algorithm, or NULL
*/
static struct tls_signature_hash_algorithm *
tls_signature_hash_algorithm ( struct pubkey_algorithm *pubkey,
struct digest_algorithm *digest ) {
struct tls_signature_hash_algorithm *sig_hash;
/* Identify signature and hash algorithm */
for_each_table_entry ( sig_hash, TLS_SIG_HASH_ALGORITHMS ) {
if ( ( sig_hash->pubkey == pubkey ) &&
( sig_hash->digest == digest ) ) {
return sig_hash;
}
}
return NULL;
}
/******************************************************************************
*
* Handshake verification
*
******************************************************************************
*/
/**
* Add handshake record to verification hash
*
* @v tls TLS session
* @v data Handshake record
* @v len Length of handshake record
*/
static void tls_add_handshake ( struct tls_session *tls,
const void *data, size_t len ) {
digest_update ( &md5_sha1_algorithm, tls->handshake_md5_sha1_ctx,
data, len );
digest_update ( &sha256_algorithm, tls->handshake_sha256_ctx,
data, len );
}
/**
* Calculate handshake verification hash
*
* @v tls TLS session
* @v out Output buffer
*
* Calculates the MD5+SHA1 or SHA256 digest over all handshake
* messages seen so far.
*/
static void tls_verify_handshake ( struct tls_session *tls, void *out ) {
struct digest_algorithm *digest = tls->handshake_digest;
uint8_t ctx[ digest->ctxsize ];
memcpy ( ctx, tls->handshake_ctx, sizeof ( ctx ) );
digest_final ( digest, ctx, out );
}
/******************************************************************************
*
* Record handling
*
******************************************************************************
*/
/**
* Resume TX state machine
*
* @v tls TLS session
*/
static void tls_tx_resume ( struct tls_session *tls ) {
process_add ( &tls->process );
}
/**
* Transmit Handshake record
*
* @v tls TLS session
* @v data Plaintext record
* @v len Length of plaintext record
* @ret rc Return status code
*/
static int tls_send_handshake ( struct tls_session *tls,
void *data, size_t len ) {
/* Add to handshake digest */
tls_add_handshake ( tls, data, len );
/* Send record */
return tls_send_plaintext ( tls, TLS_TYPE_HANDSHAKE, data, len );
}
/**
* Transmit Client Hello record
*
* @v tls TLS session
* @ret rc Return status code
*/
static int tls_send_client_hello ( struct tls_session *tls ) {
struct {
uint32_t type_length;
uint16_t version;
uint8_t random[32];
uint8_t session_id_len;
uint16_t cipher_suite_len;
uint16_t cipher_suites[TLS_NUM_CIPHER_SUITES];
uint8_t compression_methods_len;
uint8_t compression_methods[1];
uint16_t extensions_len;
struct {
uint16_t server_name_type;
uint16_t server_name_len;
struct {
uint16_t len;
struct {
uint8_t type;
uint16_t len;
uint8_t name[ strlen ( tls->name ) ];
} __attribute__ (( packed )) list[1];
} __attribute__ (( packed )) server_name;
uint16_t max_fragment_length_type;
uint16_t max_fragment_length_len;
struct {
uint8_t max;
} __attribute__ (( packed )) max_fragment_length;
uint16_t signature_algorithms_type;
uint16_t signature_algorithms_len;
struct {
uint16_t len;
struct tls_signature_hash_id
code[TLS_NUM_SIG_HASH_ALGORITHMS];
} __attribute__ (( packed )) signature_algorithms;
} __attribute__ (( packed )) extensions;
} __attribute__ (( packed )) hello;
struct tls_cipher_suite *suite;
struct tls_signature_hash_algorithm *sighash;
unsigned int i;
memset ( &hello, 0, sizeof ( hello ) );
hello.type_length = ( cpu_to_le32 ( TLS_CLIENT_HELLO ) |
htonl ( sizeof ( hello ) -
sizeof ( hello.type_length ) ) );
hello.version = htons ( tls->version );
memcpy ( &hello.random, &tls->client_random, sizeof ( hello.random ) );
hello.cipher_suite_len = htons ( sizeof ( hello.cipher_suites ) );
i = 0 ; for_each_table_entry ( suite, TLS_CIPHER_SUITES )
hello.cipher_suites[i++] = suite->code;
hello.compression_methods_len = sizeof ( hello.compression_methods );
hello.extensions_len = htons ( sizeof ( hello.extensions ) );
hello.extensions.server_name_type = htons ( TLS_SERVER_NAME );
hello.extensions.server_name_len
= htons ( sizeof ( hello.extensions.server_name ) );
hello.extensions.server_name.len
= htons ( sizeof ( hello.extensions.server_name.list ) );
hello.extensions.server_name.list[0].type = TLS_SERVER_NAME_HOST_NAME;
hello.extensions.server_name.list[0].len
= htons ( sizeof ( hello.extensions.server_name.list[0].name ));
memcpy ( hello.extensions.server_name.list[0].name, tls->name,
sizeof ( hello.extensions.server_name.list[0].name ) );
hello.extensions.max_fragment_length_type
= htons ( TLS_MAX_FRAGMENT_LENGTH );
hello.extensions.max_fragment_length_len
= htons ( sizeof ( hello.extensions.max_fragment_length ) );
hello.extensions.max_fragment_length.max
= TLS_MAX_FRAGMENT_LENGTH_4096;
hello.extensions.signature_algorithms_type
= htons ( TLS_SIGNATURE_ALGORITHMS );
hello.extensions.signature_algorithms_len
= htons ( sizeof ( hello.extensions.signature_algorithms ) );
hello.extensions.signature_algorithms.len
= htons ( sizeof ( hello.extensions.signature_algorithms.code));
i = 0 ; for_each_table_entry ( sighash, TLS_SIG_HASH_ALGORITHMS )
hello.extensions.signature_algorithms.code[i++] = sighash->code;
return tls_send_handshake ( tls, &hello, sizeof ( hello ) );
}
/**
* Transmit Certificate record
*
* @v tls TLS session
* @ret rc Return status code
*/
static int tls_send_certificate ( struct tls_session *tls ) {
struct {
uint32_t type_length;
tls24_t length;
struct {
tls24_t length;
uint8_t data[ tls->cert->raw.len ];
} __attribute__ (( packed )) certificates[1];
} __attribute__ (( packed )) *certificate;
int rc;
/* Allocate storage for Certificate record (which may be too
* large for the stack).
*/
certificate = zalloc ( sizeof ( *certificate ) );
if ( ! certificate )
return -ENOMEM_CERTIFICATE;
/* Populate record */
certificate->type_length =
( cpu_to_le32 ( TLS_CERTIFICATE ) |
htonl ( sizeof ( *certificate ) -
sizeof ( certificate->type_length ) ) );
tls_set_uint24 ( &certificate->length,
sizeof ( certificate->certificates ) );
tls_set_uint24 ( &certificate->certificates[0].length,
sizeof ( certificate->certificates[0].data ) );
memcpy ( certificate->certificates[0].data,
tls->cert->raw.data,
sizeof ( certificate->certificates[0].data ) );
/* Transmit record */
rc = tls_send_handshake ( tls, certificate, sizeof ( *certificate ) );
/* Free record */
free ( certificate );
return rc;
}
/**
* Transmit Client Key Exchange record
*
* @v tls TLS session
* @ret rc Return status code
*/
static int tls_send_client_key_exchange ( struct tls_session *tls ) {
struct tls_cipherspec *cipherspec = &tls->tx_cipherspec_pending;
struct pubkey_algorithm *pubkey = cipherspec->suite->pubkey;
size_t max_len = pubkey_max_len ( pubkey, cipherspec->pubkey_ctx );
struct {
uint32_t type_length;
uint16_t encrypted_pre_master_secret_len;
uint8_t encrypted_pre_master_secret[max_len];
} __attribute__ (( packed )) key_xchg;
size_t unused;
int len;
int rc;
/* Encrypt pre-master secret using server's public key */
memset ( &key_xchg, 0, sizeof ( key_xchg ) );
len = pubkey_encrypt ( pubkey, cipherspec->pubkey_ctx,
&tls->pre_master_secret,
sizeof ( tls->pre_master_secret ),
key_xchg.encrypted_pre_master_secret );
if ( len < 0 ) {
rc = len;
DBGC ( tls, "TLS %p could not encrypt pre-master secret: %s\n",
tls, strerror ( rc ) );
return rc;
}
unused = ( max_len - len );
key_xchg.type_length =
( cpu_to_le32 ( TLS_CLIENT_KEY_EXCHANGE ) |
htonl ( sizeof ( key_xchg ) -
sizeof ( key_xchg.type_length ) - unused ) );
key_xchg.encrypted_pre_master_secret_len =
htons ( sizeof ( key_xchg.encrypted_pre_master_secret ) -
unused );
return tls_send_handshake ( tls, &key_xchg,
( sizeof ( key_xchg ) - unused ) );
}
/**
* Transmit Certificate Verify record
*
* @v tls TLS session
* @ret rc Return status code
*/
static int tls_send_certificate_verify ( struct tls_session *tls ) {
struct digest_algorithm *digest = tls->handshake_digest;
struct x509_certificate *cert = tls->cert;
struct pubkey_algorithm *pubkey = cert->signature_algorithm->pubkey;
uint8_t digest_out[ digest->digestsize ];
uint8_t ctx[ pubkey->ctxsize ];
struct tls_signature_hash_algorithm *sig_hash = NULL;
int rc;
/* Generate digest to be signed */
tls_verify_handshake ( tls, digest_out );
/* Initialise public-key algorithm */
if ( ( rc = pubkey_init ( pubkey, ctx, private_key.data,
private_key.len ) ) != 0 ) {
DBGC ( tls, "TLS %p could not initialise %s client private "
"key: %s\n", tls, pubkey->name, strerror ( rc ) );
goto err_pubkey_init;
}
/* TLSv1.2 and later use explicit algorithm identifiers */
if ( tls->version >= TLS_VERSION_TLS_1_2 ) {
sig_hash = tls_signature_hash_algorithm ( pubkey, digest );
if ( ! sig_hash ) {
DBGC ( tls, "TLS %p could not identify (%s,%s) "
"signature and hash algorithm\n", tls,
pubkey->name, digest->name );
rc = -ENOTSUP_SIG_HASH;
goto err_sig_hash;
}
}
/* Generate and transmit record */
{
size_t max_len = pubkey_max_len ( pubkey, ctx );
int use_sig_hash = ( ( sig_hash == NULL ) ? 0 : 1 );
struct {
uint32_t type_length;
struct tls_signature_hash_id sig_hash[use_sig_hash];
uint16_t signature_len;
uint8_t signature[max_len];
} __attribute__ (( packed )) certificate_verify;
size_t unused;
int len;
/* Sign digest */
len = pubkey_sign ( pubkey, ctx, digest, digest_out,
certificate_verify.signature );
if ( len < 0 ) {
rc = len;
DBGC ( tls, "TLS %p could not sign %s digest using %s "
"client private key: %s\n", tls, digest->name,
pubkey->name, strerror ( rc ) );
goto err_pubkey_sign;
}
unused = ( max_len - len );
/* Construct Certificate Verify record */
certificate_verify.type_length =
( cpu_to_le32 ( TLS_CERTIFICATE_VERIFY ) |
htonl ( sizeof ( certificate_verify ) -
sizeof ( certificate_verify.type_length ) -
unused ) );
if ( use_sig_hash ) {
memcpy ( &certificate_verify.sig_hash[0],
&sig_hash->code,
sizeof ( certificate_verify.sig_hash[0] ) );
}
certificate_verify.signature_len =
htons ( sizeof ( certificate_verify.signature ) -
unused );
/* Transmit record */
rc = tls_send_handshake ( tls, &certificate_verify,
( sizeof ( certificate_verify ) - unused ) );
}
err_pubkey_sign:
err_sig_hash:
pubkey_final ( pubkey, ctx );
err_pubkey_init:
return rc;
}
/**
* Transmit Change Cipher record
*
* @v tls TLS session
* @ret rc Return status code
*/
static int tls_send_change_cipher ( struct tls_session *tls ) {
static const uint8_t change_cipher[1] = { 1 };
return tls_send_plaintext ( tls, TLS_TYPE_CHANGE_CIPHER,
change_cipher, sizeof ( change_cipher ) );
}
/**
* Transmit Finished record
*
* @v tls TLS session
* @ret rc Return status code
*/
static int tls_send_finished ( struct tls_session *tls ) {
struct digest_algorithm *digest = tls->handshake_digest;
struct {
uint32_t type_length;
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 ) -
sizeof ( finished.type_length ) ) );
tls_verify_handshake ( tls, digest_out );
tls_prf_label ( tls, &tls->master_secret, sizeof ( tls->master_secret ),
finished.verify_data, sizeof ( finished.verify_data ),
"client finished", digest_out, sizeof ( digest_out ) );
/* Transmit record */
if ( ( rc = tls_send_handshake ( tls, &finished,
sizeof ( finished ) ) ) != 0 )
return rc;
/* Mark client as finished */
pending_put ( &tls->client_negotiation );
return 0;
}
/**
* Receive new Change Cipher record
*
* @v tls TLS session
* @v data Plaintext record
* @v len Length of plaintext record
* @ret rc Return status code
*/
static int tls_new_change_cipher ( struct tls_session *tls,
const void *data, size_t len ) {
int rc;
if ( ( len != 1 ) || ( *( ( uint8_t * ) data ) != 1 ) ) {
DBGC ( tls, "TLS %p received invalid Change Cipher\n", tls );
DBGC_HD ( tls, data, len );
return -EINVAL_CHANGE_CIPHER;
}
if ( ( rc = tls_change_cipher ( tls, &tls->rx_cipherspec_pending,
&tls->rx_cipherspec ) ) != 0 ) {
DBGC ( tls, "TLS %p could not activate RX cipher: %s\n",
tls, strerror ( rc ) );
return rc;
}
tls->rx_seq = ~( ( uint64_t ) 0 );
return 0;
}
/**
* Receive new Alert record
*
* @v tls TLS session
* @v data Plaintext record
* @v len Length of plaintext record
* @ret rc Return status code
*/
static int tls_new_alert ( struct tls_session *tls, const void *data,
size_t len ) {
const struct {
uint8_t level;
uint8_t description;
char next[0];
} __attribute__ (( packed )) *alert = data;
/* Sanity check */
if ( sizeof ( *alert ) != len ) {
DBGC ( tls, "TLS %p received overlength Alert\n", tls );
DBGC_HD ( tls, data, len );
return -EINVAL_ALERT;
}
switch ( alert->level ) {
case TLS_ALERT_WARNING:
DBGC ( tls, "TLS %p received warning alert %d\n",
tls, alert->description );
return 0;
case TLS_ALERT_FATAL:
DBGC ( tls, "TLS %p received fatal alert %d\n",
tls, alert->description );
return -EPERM_ALERT;
default:
DBGC ( tls, "TLS %p received unknown alert level %d"
"(alert %d)\n", tls, alert->level, alert->description );
return -EIO_ALERT;
}
}
/**
* Receive new Server Hello handshake record
*
* @v tls TLS session
* @v data Plaintext handshake record
* @v len Length of plaintext handshake record
* @ret rc Return status code
*/
static int tls_new_server_hello ( struct tls_session *tls,
const void *data, size_t len ) {
const struct {
uint16_t version;
uint8_t random[32];
uint8_t session_id_len;
uint8_t session_id[0];
} __attribute__ (( packed )) *hello_a = data;
const uint8_t *session_id;
const struct {
uint16_t cipher_suite;
uint8_t compression_method;
char next[0];
} __attribute__ (( packed )) *hello_b;
uint16_t version;
int rc;
/* Parse header */
if ( ( sizeof ( *hello_a ) > len ) ||
( hello_a->session_id_len > ( len - sizeof ( *hello_a ) ) ) ||
( sizeof ( *hello_b ) > ( len - sizeof ( *hello_a ) -
hello_a->session_id_len ) ) ) {
DBGC ( tls, "TLS %p received underlength Server Hello\n", tls );
DBGC_HD ( tls, data, len );
return -EINVAL_HELLO;
}
session_id = hello_a->session_id;
hello_b = ( ( void * ) ( session_id + hello_a->session_id_len ) );
/* Check and store protocol version */
version = ntohs ( hello_a->version );
if ( version < TLS_VERSION_TLS_1_0 ) {
DBGC ( tls, "TLS %p does not support protocol version %d.%d\n",
tls, ( version >> 8 ), ( version & 0xff ) );
return -ENOTSUP_VERSION;
}
if ( version > tls->version ) {
DBGC ( tls, "TLS %p server attempted to illegally upgrade to "
"protocol version %d.%d\n",
tls, ( version >> 8 ), ( version & 0xff ) );
return -EPROTO_VERSION;
}
tls->version = version;
DBGC ( tls, "TLS %p using protocol version %d.%d\n",
tls, ( version >> 8 ), ( version & 0xff ) );
/* Use MD5+SHA1 digest algorithm for handshake verification
* for versions earlier than TLSv1.2.
*/
if ( tls->version < TLS_VERSION_TLS_1_2 ) {
tls->handshake_digest = &md5_sha1_algorithm;
tls->handshake_ctx = tls->handshake_md5_sha1_ctx;
}
/* Copy out server random bytes */
memcpy ( &tls->server_random, &hello_a->random,
sizeof ( tls->server_random ) );
/* Select cipher suite */
if ( ( rc = tls_select_cipher ( tls, hello_b->cipher_suite ) ) != 0 )
return rc;
/* Generate secrets */
tls_generate_master_secret ( tls );
if ( ( rc = tls_generate_keys ( tls ) ) != 0 )
return rc;
return 0;
}
/**
* Parse certificate chain
*
* @v tls TLS session
* @v data Certificate chain
* @v len Length of certificate chain
* @ret rc Return status code
*/
static int tls_parse_chain ( struct tls_session *tls,
const void *data, size_t len ) {
size_t remaining = len;
int rc;
/* Free any existing certificate chain */
x509_chain_put ( tls->chain );
tls->chain = NULL;
/* Create certificate chain */
tls->chain = x509_alloc_chain();
if ( ! tls->chain ) {
rc = -ENOMEM_CHAIN;
goto err_alloc_chain;
}
/* Add certificates to chain */
while ( remaining ) {
const struct {
tls24_t length;
uint8_t data[0];
} __attribute__ (( packed )) *certificate = data;
size_t certificate_len;
size_t record_len;
struct x509_certificate *cert;
/* Parse header */
if ( sizeof ( *certificate ) > remaining ) {
DBGC ( tls, "TLS %p underlength certificate:\n", tls );
DBGC_HDA ( tls, 0, data, remaining );
rc = -EINVAL_CERTIFICATE;
goto err_underlength;
}
certificate_len = tls_uint24 ( &certificate->length );
if ( certificate_len > ( remaining - sizeof ( *certificate ) )){
DBGC ( tls, "TLS %p overlength certificate:\n", tls );
DBGC_HDA ( tls, 0, data, remaining );
rc = -EINVAL_CERTIFICATE;
goto err_overlength;
}
record_len = ( sizeof ( *certificate ) + certificate_len );
/* Add certificate to chain */
if ( ( rc = x509_append_raw ( tls->chain, certificate->data,
certificate_len ) ) != 0 ) {
DBGC ( tls, "TLS %p could not append certificate: %s\n",
tls, strerror ( rc ) );
DBGC_HDA ( tls, 0, data, remaining );
goto err_parse;
}
cert = x509_last ( tls->chain );
DBGC ( tls, "TLS %p found certificate %s\n",
tls, x509_name ( cert ) );
/* Move to next certificate in list */
data += record_len;
remaining -= record_len;
}
return 0;
err_parse:
err_overlength:
err_underlength:
x509_chain_put ( tls->chain );
tls->chain = NULL;
err_alloc_chain:
return rc;
}
/**
* Receive new Certificate handshake record
*
* @v tls TLS session
* @v data Plaintext handshake record
* @v len Length of plaintext handshake record
* @ret rc Return status code
*/
static int tls_new_certificate ( struct tls_session *tls,
const void *data, size_t len ) {
const struct {
tls24_t length;
uint8_t certificates[0];
} __attribute__ (( packed )) *certificate = data;
size_t certificates_len;
int rc;
/* Parse header */
if ( sizeof ( *certificate ) > len ) {
DBGC ( tls, "TLS %p received underlength Server Certificate\n",
tls );
DBGC_HD ( tls, data, len );
return -EINVAL_CERTIFICATES;
}
certificates_len = tls_uint24 ( &certificate->length );
if ( certificates_len > ( len - sizeof ( *certificate ) ) ) {
DBGC ( tls, "TLS %p received overlength Server Certificate\n",
tls );
DBGC_HD ( tls, data, len );
return -EINVAL_CERTIFICATES;
}
/* Parse certificate chain */
if ( ( rc = tls_parse_chain ( tls, certificate->certificates,
certificates_len ) ) != 0 )
return rc;
return 0;
}
/**
* Receive new Certificate Request handshake record
*
* @v tls TLS session
* @v data Plaintext handshake record
* @v len Length of plaintext handshake record
* @ret rc Return status code
*/
static int tls_new_certificate_request ( struct tls_session *tls,
const void *data __unused,
size_t len __unused ) {
/* We can only send a single certificate, so there is no point
* in parsing the Certificate Request.
*/
/* Free any existing client certificate */
x509_put ( tls->cert );
/* Determine client certificate to be sent */
tls->cert = certstore_find_key ( &private_key );
if ( ! tls->cert ) {
DBGC ( tls, "TLS %p could not find certificate corresponding "
"to private key\n", tls );
return -EPERM_CLIENT_CERT;
}
x509_get ( tls->cert );
DBGC ( tls, "TLS %p sending client certificate %s\n",
tls, x509_name ( tls->cert ) );
return 0;
}
/**
* Receive new Server Hello Done handshake record
*
* @v tls TLS session
* @v data Plaintext handshake record
* @v len Length of plaintext handshake record
* @ret rc Return status code
*/
static int tls_new_server_hello_done ( struct tls_session *tls,
const void *data, size_t len ) {
const struct {
char next[0];
} __attribute__ (( packed )) *hello_done = data;
int rc;
/* Sanity check */
if ( sizeof ( *hello_done ) != len ) {
DBGC ( tls, "TLS %p received overlength Server Hello Done\n",
tls );
DBGC_HD ( tls, data, len );
return -EINVAL_HELLO_DONE;
}
/* 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;
}
/**
* Receive new Finished handshake record
*
* @v tls TLS session
* @v data Plaintext handshake record
* @v len Length of plaintext handshake record
* @ret rc Return status code
*/
static int tls_new_finished ( struct tls_session *tls,
const void *data, size_t len ) {
struct digest_algorithm *digest = tls->handshake_digest;
const struct {
uint8_t verify_data[12];
char next[0];
} __attribute__ (( packed )) *finished = data;
uint8_t digest_out[ digest->digestsize ];
uint8_t verify_data[ sizeof ( finished->verify_data ) ];
/* Sanity check */
if ( sizeof ( *finished ) != len ) {
DBGC ( tls, "TLS %p received overlength Finished\n", tls );
DBGC_HD ( tls, data, len );
return -EINVAL_FINISHED;
}
/* Verify data */
tls_verify_handshake ( tls, digest_out );
tls_prf_label ( tls, &tls->master_secret, sizeof ( tls->master_secret ),
verify_data, sizeof ( verify_data ), "server finished",
digest_out, sizeof ( digest_out ) );
if ( memcmp ( verify_data, finished->verify_data,
sizeof ( verify_data ) ) != 0 ) {
DBGC ( tls, "TLS %p verification failed\n", tls );
return -EPERM_VERIFY;
}
/* Mark server as finished */
pending_put ( &tls->server_negotiation );
/* Send notification of a window change */
xfer_window_changed ( &tls->plainstream );
return 0;
}
/**
* Receive new Handshake record
*
* @v tls TLS session
* @v data Plaintext record
* @v len Length of plaintext record
* @ret rc Return status code
*/
static int tls_new_handshake ( struct tls_session *tls,
const void *data, size_t len ) {
size_t remaining = len;
int rc;
while ( remaining ) {
const struct {
uint8_t type;
tls24_t length;
uint8_t payload[0];
} __attribute__ (( packed )) *handshake = data;
const void *payload;
size_t payload_len;
size_t record_len;
/* Parse header */
if ( sizeof ( *handshake ) > remaining ) {
DBGC ( tls, "TLS %p received underlength Handshake\n",
tls );
DBGC_HD ( tls, data, remaining );
return -EINVAL_HANDSHAKE;
}
payload_len = tls_uint24 ( &handshake->length );
if ( payload_len > ( remaining - sizeof ( *handshake ) ) ) {
DBGC ( tls, "TLS %p received overlength Handshake\n",
tls );
DBGC_HD ( tls, data, len );
return -EINVAL_HANDSHAKE;
}
payload = &handshake->payload;
record_len = ( sizeof ( *handshake ) + payload_len );
/* Handle payload */
switch ( handshake->type ) {
case TLS_SERVER_HELLO:
rc = tls_new_server_hello ( tls, payload, payload_len );
break;
case TLS_CERTIFICATE:
rc = tls_new_certificate ( tls, payload, payload_len );
break;
case TLS_CERTIFICATE_REQUEST:
rc = tls_new_certificate_request ( tls, payload,
payload_len );
break;
case TLS_SERVER_HELLO_DONE:
rc = tls_new_server_hello_done ( tls, payload,
payload_len );
break;
case TLS_FINISHED:
rc = tls_new_finished ( tls, payload, payload_len );
break;
default:
DBGC ( tls, "TLS %p ignoring handshake type %d\n",
tls, handshake->type );
rc = 0;
break;
}
/* Add to handshake digest (except for Hello Requests,
* which are explicitly excluded).
*/
if ( handshake->type != TLS_HELLO_REQUEST )
tls_add_handshake ( tls, data, record_len );
/* Abort on failure */
if ( rc != 0 )
return rc;
/* Move to next handshake record */
data += record_len;
remaining -= record_len;
}
return 0;
}
/**
* Receive new record
*
* @v tls TLS session
* @v type Record type
* @v rx_data List of received data buffers
* @ret rc Return status code
*/
static int tls_new_record ( struct tls_session *tls, unsigned int type,
struct list_head *rx_data ) {
struct io_buffer *iobuf;
int ( * handler ) ( struct tls_session *tls, const void *data,
size_t len );
int rc;
/* Deliver data records to the plainstream interface */
if ( type == TLS_TYPE_DATA ) {
/* Fail unless we are ready to receive data */
if ( ! tls_ready ( tls ) )
return -ENOTCONN;
/* Deliver each I/O buffer in turn */
while ( ( iobuf = list_first_entry ( rx_data, struct io_buffer,
list ) ) ) {
list_del ( &iobuf->list );
if ( ( rc = xfer_deliver_iob ( &tls->plainstream,
iobuf ) ) != 0 ) {
DBGC ( tls, "TLS %p could not deliver data: "
"%s\n", tls, strerror ( rc ) );
return rc;
}
}
return 0;
}
/* For all other records, merge into a single I/O buffer */
iobuf = iob_concatenate ( rx_data );
if ( ! iobuf ) {
DBGC ( tls, "TLS %p could not concatenate non-data record "
"type %d\n", tls, type );
return -ENOMEM_RX_CONCAT;
}
/* Determine handler */
switch ( type ) {
case TLS_TYPE_CHANGE_CIPHER:
handler = tls_new_change_cipher;
break;
case TLS_TYPE_ALERT:
handler = tls_new_alert;
break;
case TLS_TYPE_HANDSHAKE:
handler = tls_new_handshake;
break;
default:
/* RFC4346 says that we should just ignore unknown
* record types.
*/
handler = NULL;
DBGC ( tls, "TLS %p ignoring record type %d\n", tls, type );
break;
}
/* Handle record and free I/O buffer */
rc = ( handler ? handler ( tls, iobuf->data, iob_len ( iobuf ) ) : 0 );
free_iob ( iobuf );
return rc;
}
/******************************************************************************
*
* Record encryption/decryption
*
******************************************************************************
*/
/**
* Initialise HMAC
*
* @v cipherspec Cipher specification
* @v ctx Context
* @v seq Sequence number
* @v tlshdr TLS header
*/
static void tls_hmac_init ( struct tls_cipherspec *cipherspec, void *ctx,
uint64_t seq, struct tls_header *tlshdr ) {
struct digest_algorithm *digest = cipherspec->suite->digest;
hmac_init ( digest, ctx, cipherspec->mac_secret, &digest->digestsize );
seq = cpu_to_be64 ( seq );
hmac_update ( digest, ctx, &seq, sizeof ( seq ) );
hmac_update ( digest, ctx, tlshdr, sizeof ( *tlshdr ) );
}
/**
* Update HMAC
*
* @v cipherspec Cipher specification
* @v ctx Context
* @v data Data
* @v len Length of data
*/
static void tls_hmac_update ( struct tls_cipherspec *cipherspec, void *ctx,
const void *data, size_t len ) {
struct digest_algorithm *digest = cipherspec->suite->digest;
hmac_update ( digest, ctx, data, len );
}
/**
* Finalise HMAC
*
* @v cipherspec Cipher specification
* @v ctx Context
* @v mac HMAC to fill in
*/
static void tls_hmac_final ( struct tls_cipherspec *cipherspec, void *ctx,
void *hmac ) {
struct digest_algorithm *digest = cipherspec->suite->digest;
hmac_final ( digest, ctx, cipherspec->mac_secret,
&digest->digestsize, hmac );
}
/**
* Calculate HMAC
*
* @v cipherspec Cipher specification
* @v seq Sequence number
* @v tlshdr TLS header
* @v data Data
* @v len Length of data
* @v mac HMAC to fill in
*/
static void tls_hmac ( struct tls_cipherspec *cipherspec,
uint64_t seq, struct tls_header *tlshdr,
const void *data, size_t len, void *hmac ) {
struct digest_algorithm *digest = cipherspec->suite->digest;
uint8_t ctx[digest->ctxsize];
tls_hmac_init ( cipherspec, ctx, seq, tlshdr );
tls_hmac_update ( cipherspec, ctx, data, len );
tls_hmac_final ( cipherspec, ctx, hmac );
}
/**
* Allocate and assemble stream-ciphered record from data and MAC portions
*
* @v tls TLS session
* @ret data Data
* @ret len Length of data
* @ret digest MAC digest
* @ret plaintext_len Length of plaintext record
* @ret plaintext Allocated plaintext record
*/
static void * __malloc tls_assemble_stream ( struct tls_session *tls,
const void *data, size_t len,
void *digest, size_t *plaintext_len ) {
size_t mac_len = tls->tx_cipherspec.suite->digest->digestsize;
void *plaintext;
void *content;
void *mac;
/* Calculate stream-ciphered struct length */
*plaintext_len = ( len + mac_len );
/* Allocate stream-ciphered struct */
plaintext = malloc ( *plaintext_len );
if ( ! plaintext )
return NULL;
content = plaintext;
mac = ( content + len );
/* Fill in stream-ciphered struct */
memcpy ( content, data, len );
memcpy ( mac, digest, mac_len );
return plaintext;
}
/**
* Allocate and assemble block-ciphered record from data and MAC portions
*
* @v tls TLS session
* @ret data Data
* @ret len Length of data
* @ret digest MAC digest
* @ret plaintext_len Length of plaintext record
* @ret plaintext Allocated plaintext record
*/
static void * tls_assemble_block ( struct tls_session *tls,
const void *data, size_t len,
void *digest, size_t *plaintext_len ) {
size_t blocksize = tls->tx_cipherspec.suite->cipher->blocksize;
size_t mac_len = tls->tx_cipherspec.suite->digest->digestsize;
size_t iv_len;
size_t padding_len;
void *plaintext;
void *iv;
void *content;
void *mac;
void *padding;
/* TLSv1.1 and later use an explicit IV */
iv_len = ( ( tls->version >= TLS_VERSION_TLS_1_1 ) ? blocksize : 0 );
/* Calculate block-ciphered struct length */
padding_len = ( ( blocksize - 1 ) & -( iv_len + len + mac_len + 1 ) );
*plaintext_len = ( iv_len + len + mac_len + padding_len + 1 );
/* Allocate block-ciphered struct */
plaintext = malloc ( *plaintext_len );
if ( ! plaintext )
return NULL;
iv = plaintext;
content = ( iv + iv_len );
mac = ( content + len );
padding = ( mac + mac_len );
/* Fill in block-ciphered struct */
tls_generate_random ( tls, iv, iv_len );
memcpy ( content, data, len );
memcpy ( mac, digest, mac_len );
memset ( padding, padding_len, ( padding_len + 1 ) );
return plaintext;
}
/**
* Send plaintext record
*
* @v tls TLS session
* @v type Record type
* @v data Plaintext record
* @v len Length of plaintext record
* @ret rc Return status code
*/
static int tls_send_plaintext ( struct tls_session *tls, unsigned int type,
const void *data, size_t len ) {
struct tls_header plaintext_tlshdr;
struct tls_header *tlshdr;
struct tls_cipherspec *cipherspec = &tls->tx_cipherspec;
struct cipher_algorithm *cipher = cipherspec->suite->cipher;
void *plaintext = NULL;
size_t plaintext_len;
struct io_buffer *ciphertext = NULL;
size_t ciphertext_len;
size_t mac_len = cipherspec->suite->digest->digestsize;
uint8_t mac[mac_len];
int rc;
/* Construct header */
plaintext_tlshdr.type = type;
plaintext_tlshdr.version = htons ( tls->version );
plaintext_tlshdr.length = htons ( len );
/* Calculate MAC */
tls_hmac ( cipherspec, tls->tx_seq, &plaintext_tlshdr, data, len, mac );
/* Allocate and assemble plaintext struct */
if ( is_stream_cipher ( cipher ) ) {
plaintext = tls_assemble_stream ( tls, data, len, mac,
&plaintext_len );
} else {
plaintext = tls_assemble_block ( tls, data, len, mac,
&plaintext_len );
}
if ( ! plaintext ) {
DBGC ( tls, "TLS %p could not allocate %zd bytes for "
"plaintext\n", tls, plaintext_len );
rc = -ENOMEM_TX_PLAINTEXT;
goto done;
}
DBGC2 ( tls, "Sending plaintext data:\n" );
DBGC2_HD ( tls, plaintext, plaintext_len );
/* Allocate ciphertext */
ciphertext_len = ( sizeof ( *tlshdr ) + plaintext_len );
ciphertext = xfer_alloc_iob ( &tls->cipherstream, ciphertext_len );
if ( ! ciphertext ) {
DBGC ( tls, "TLS %p could not allocate %zd bytes for "
"ciphertext\n", tls, ciphertext_len );
rc = -ENOMEM_TX_CIPHERTEXT;
goto done;
}
/* Assemble ciphertext */
tlshdr = iob_put ( ciphertext, sizeof ( *tlshdr ) );
tlshdr->type = type;
tlshdr->version = htons ( tls->version );
tlshdr->length = htons ( plaintext_len );
memcpy ( cipherspec->cipher_next_ctx, cipherspec->cipher_ctx,
cipher->ctxsize );
cipher_encrypt ( cipher, cipherspec->cipher_next_ctx, plaintext,
iob_put ( ciphertext, plaintext_len ), plaintext_len );
/* Free plaintext as soon as possible to conserve memory */
free ( plaintext );
plaintext = NULL;
/* Send ciphertext */
if ( ( rc = xfer_deliver_iob ( &tls->cipherstream,
iob_disown ( ciphertext ) ) ) != 0 ) {
DBGC ( tls, "TLS %p could not deliver ciphertext: %s\n",
tls, strerror ( rc ) );
goto done;
}
/* Update TX state machine to next record */
tls->tx_seq += 1;
memcpy ( tls->tx_cipherspec.cipher_ctx,
tls->tx_cipherspec.cipher_next_ctx, cipher->ctxsize );
done:
free ( plaintext );
free_iob ( ciphertext );
return rc;
}
/**
* Split stream-ciphered record into data and MAC portions
*
* @v tls TLS session
* @v rx_data List of received data buffers
* @v mac MAC to fill in
* @ret rc Return status code
*/
static int tls_split_stream ( struct tls_session *tls,
struct list_head *rx_data, void **mac ) {
size_t mac_len = tls->rx_cipherspec.suite->digest->digestsize;
struct io_buffer *iobuf;
/* Extract MAC */
iobuf = list_last_entry ( rx_data, struct io_buffer, list );
assert ( iobuf != NULL );
if ( iob_len ( iobuf ) < mac_len ) {
DBGC ( tls, "TLS %p received underlength MAC\n", tls );
DBGC_HD ( tls, iobuf->data, iob_len ( iobuf ) );
return -EINVAL_STREAM;
}
iob_unput ( iobuf, mac_len );
*mac = iobuf->tail;
return 0;
}
/**
* Split block-ciphered record into data and MAC portions
*
* @v tls TLS session
* @v rx_data List of received data buffers
* @v mac MAC to fill in
* @ret rc Return status code
*/
static int tls_split_block ( struct tls_session *tls,
struct list_head *rx_data, void **mac ) {
size_t mac_len = tls->rx_cipherspec.suite->digest->digestsize;
struct io_buffer *iobuf;
size_t iv_len;
uint8_t *padding_final;
uint8_t *padding;
size_t padding_len;
/* TLSv1.1 and later use an explicit IV */
iobuf = list_first_entry ( rx_data, struct io_buffer, list );
iv_len = ( ( tls->version >= TLS_VERSION_TLS_1_1 ) ?
tls->rx_cipherspec.suite->cipher->blocksize : 0 );
if ( iob_len ( iobuf ) < iv_len ) {
DBGC ( tls, "TLS %p received underlength IV\n", tls );
DBGC_HD ( tls, iobuf->data, iob_len ( iobuf ) );
return -EINVAL_BLOCK;
}
iob_pull ( iobuf, iv_len );
/* Extract and verify padding */
iobuf = list_last_entry ( rx_data, struct io_buffer, list );
padding_final = ( iobuf->tail - 1 );
padding_len = *padding_final;
if ( ( padding_len + 1 ) > iob_len ( iobuf ) ) {
DBGC ( tls, "TLS %p received underlength padding\n", tls );
DBGC_HD ( tls, iobuf->data, iob_len ( iobuf ) );
return -EINVAL_BLOCK;
}
iob_unput ( iobuf, ( padding_len + 1 ) );
for ( padding = iobuf->tail ; padding < padding_final ; padding++ ) {
if ( *padding != padding_len ) {
DBGC ( tls, "TLS %p received bad padding\n", tls );
DBGC_HD ( tls, padding, padding_len );
return -EINVAL_PADDING;
}
}
/* Extract MAC */
if ( iob_len ( iobuf ) < mac_len ) {
DBGC ( tls, "TLS %p received underlength MAC\n", tls );
DBGC_HD ( tls, iobuf->data, iob_len ( iobuf ) );
return -EINVAL_BLOCK;
}
iob_unput ( iobuf, mac_len );
*mac = iobuf->tail;
return 0;
}
/**
* Receive new ciphertext record
*
* @v tls TLS session
* @v tlshdr Record header
* @v rx_data List of received data buffers
* @ret rc Return status code
*/
static int tls_new_ciphertext ( struct tls_session *tls,
struct tls_header *tlshdr,
struct list_head *rx_data ) {
struct tls_header plaintext_tlshdr;
struct tls_cipherspec *cipherspec = &tls->rx_cipherspec;
struct cipher_algorithm *cipher = cipherspec->suite->cipher;
struct digest_algorithm *digest = cipherspec->suite->digest;
uint8_t ctx[digest->ctxsize];
uint8_t verify_mac[digest->digestsize];
struct io_buffer *iobuf;
void *mac;
size_t len = 0;
int rc;
/* Decrypt the received data */
list_for_each_entry ( iobuf, &tls->rx_data, list ) {
cipher_decrypt ( cipher, cipherspec->cipher_ctx,
iobuf->data, iobuf->data, iob_len ( iobuf ) );
}
/* Split record into content and MAC */
if ( is_stream_cipher ( cipher ) ) {
if ( ( rc = tls_split_stream ( tls, rx_data, &mac ) ) != 0 )
return rc;
} else {
if ( ( rc = tls_split_block ( tls, rx_data, &mac ) ) != 0 )
return rc;
}
/* Calculate total length */
DBGC2 ( tls, "Received plaintext data:\n" );
list_for_each_entry ( iobuf, rx_data, list ) {
DBGC2_HD ( tls, iobuf->data, iob_len ( iobuf ) );
len += iob_len ( iobuf );
}
/* Verify MAC */
plaintext_tlshdr.type = tlshdr->type;
plaintext_tlshdr.version = tlshdr->version;
plaintext_tlshdr.length = htons ( len );
tls_hmac_init ( cipherspec, ctx, tls->rx_seq, &plaintext_tlshdr );
list_for_each_entry ( iobuf, rx_data, list ) {
tls_hmac_update ( cipherspec, ctx, iobuf->data,
iob_len ( iobuf ) );
}
tls_hmac_final ( cipherspec, ctx, verify_mac );
if ( memcmp ( mac, verify_mac, sizeof ( verify_mac ) ) != 0 ) {
DBGC ( tls, "TLS %p failed MAC verification\n", tls );
return -EINVAL_MAC;
}
/* Process plaintext record */
if ( ( rc = tls_new_record ( tls, tlshdr->type, rx_data ) ) != 0 )
return rc;
return 0;
}
/******************************************************************************
*
* Plaintext stream operations
*
******************************************************************************
*/
/**
* Check flow control window
*
* @v tls TLS session
* @ret len Length of window
*/
static size_t tls_plainstream_window ( struct tls_session *tls ) {
/* Block window unless we are ready to accept data */
if ( ! tls_ready ( tls ) )
return 0;
return xfer_window ( &tls->cipherstream );
}
/**
* Deliver datagram as raw data
*
* @v tls TLS session
* @v iobuf I/O buffer
* @v meta Data transfer metadata
* @ret rc Return status code
*/
static int tls_plainstream_deliver ( struct tls_session *tls,
struct io_buffer *iobuf,
struct xfer_metadata *meta __unused ) {
int rc;
/* Refuse unless we are ready to accept data */
if ( ! tls_ready ( tls ) ) {
rc = -ENOTCONN;
goto done;
}
if ( ( rc = tls_send_plaintext ( tls, TLS_TYPE_DATA, iobuf->data,
iob_len ( iobuf ) ) ) != 0 )
goto done;
done:
free_iob ( iobuf );
return rc;
}
/** TLS plaintext stream interface operations */
static struct interface_operation tls_plainstream_ops[] = {
INTF_OP ( xfer_deliver, struct tls_session *, tls_plainstream_deliver ),
INTF_OP ( xfer_window, struct tls_session *, tls_plainstream_window ),
INTF_OP ( intf_close, struct tls_session *, tls_close ),
};
/** TLS plaintext stream interface descriptor */
static struct interface_descriptor tls_plainstream_desc =
INTF_DESC_PASSTHRU ( struct tls_session, plainstream,
tls_plainstream_ops, cipherstream );
/******************************************************************************
*
* Ciphertext stream operations
*
******************************************************************************
*/
/**
* Handle received TLS header
*
* @v tls TLS session
* @ret rc Returned status code
*/
static int tls_newdata_process_header ( struct tls_session *tls ) {
size_t data_len = ntohs ( tls->rx_header.length );
size_t remaining = data_len;
size_t frag_len;
struct io_buffer *iobuf;
struct io_buffer *tmp;
int rc;
/* Allocate data buffers now that we know the length */
assert ( list_empty ( &tls->rx_data ) );
while ( remaining ) {
/* Calculate fragment length. Ensure that no block is
* smaller than TLS_RX_MIN_BUFSIZE (by increasing the
* allocation length if necessary).
*/
frag_len = remaining;
if ( frag_len > TLS_RX_BUFSIZE )
frag_len = TLS_RX_BUFSIZE;
remaining -= frag_len;
if ( remaining < TLS_RX_MIN_BUFSIZE ) {
frag_len += remaining;
remaining = 0;
}
/* Allocate buffer */
iobuf = alloc_iob_raw ( frag_len, TLS_RX_ALIGN, 0 );
if ( ! iobuf ) {
DBGC ( tls, "TLS %p could not allocate %zd of %zd "
"bytes for receive buffer\n", tls,
remaining, data_len );
rc = -ENOMEM_RX_DATA;
goto err;
}
/* Ensure tailroom is exactly what we asked for. This
* will result in unaligned I/O buffers when the
* fragment length is unaligned, which can happen only
* before we switch to using a block cipher.
*/
iob_reserve ( iobuf, ( iob_tailroom ( iobuf ) - frag_len ) );
/* Add I/O buffer to list */
list_add_tail ( &iobuf->list, &tls->rx_data );
}
/* Move to data state */
tls->rx_state = TLS_RX_DATA;
return 0;
err:
list_for_each_entry_safe ( iobuf, tmp, &tls->rx_data, list ) {
list_del ( &iobuf->list );
free_iob ( iobuf );
}
return rc;
}
/**
* Handle received TLS data payload
*
* @v tls TLS session
* @ret rc Returned status code
*/
static int tls_newdata_process_data ( struct tls_session *tls ) {
struct io_buffer *iobuf;
int rc;
/* Move current buffer to end of list */
iobuf = list_first_entry ( &tls->rx_data, struct io_buffer, list );
list_del ( &iobuf->list );
list_add_tail ( &iobuf->list, &tls->rx_data );
/* Continue receiving data if any space remains */
iobuf = list_first_entry ( &tls->rx_data, struct io_buffer, list );
if ( iob_tailroom ( iobuf ) )
return 0;
/* Process record */
if ( ( rc = tls_new_ciphertext ( tls, &tls->rx_header,
&tls->rx_data ) ) != 0 )
return rc;
/* Increment RX sequence number */
tls->rx_seq += 1;
/* Return to header state */
assert ( list_empty ( &tls->rx_data ) );
tls->rx_state = TLS_RX_HEADER;
iob_unput ( &tls->rx_header_iobuf, sizeof ( tls->rx_header ) );
return 0;
}
/**
* Receive new ciphertext
*
* @v tls TLS session
* @v iobuf I/O buffer
* @v meta Data transfer metadat
* @ret rc Return status code
*/
static int tls_cipherstream_deliver ( struct tls_session *tls,
struct io_buffer *iobuf,
struct xfer_metadata *xfer __unused ) {
size_t frag_len;
int ( * process ) ( struct tls_session *tls );
struct io_buffer *dest;
int rc;
while ( iob_len ( iobuf ) ) {
/* Select buffer according to current state */
switch ( tls->rx_state ) {
case TLS_RX_HEADER:
dest = &tls->rx_header_iobuf;
process = tls_newdata_process_header;
break;
case TLS_RX_DATA:
dest = list_first_entry ( &tls->rx_data,
struct io_buffer, list );
assert ( dest != NULL );
process = tls_newdata_process_data;
break;
default:
assert ( 0 );
rc = -EINVAL_RX_STATE;
goto done;
}
/* Copy data portion to buffer */
frag_len = iob_len ( iobuf );
if ( frag_len > iob_tailroom ( dest ) )
frag_len = iob_tailroom ( dest );
memcpy ( iob_put ( dest, frag_len ), iobuf->data, frag_len );
iob_pull ( iobuf, frag_len );
/* Process data if buffer is now full */
if ( iob_tailroom ( dest ) == 0 ) {
if ( ( rc = process ( tls ) ) != 0 ) {
tls_close ( tls, rc );
goto done;
}
}
}
rc = 0;
done:
free_iob ( iobuf );
return rc;
}
/** TLS ciphertext stream interface operations */
static struct interface_operation tls_cipherstream_ops[] = {
INTF_OP ( xfer_deliver, struct tls_session *,
tls_cipherstream_deliver ),
INTF_OP ( xfer_window_changed, struct tls_session *, tls_tx_resume ),
INTF_OP ( intf_close, struct tls_session *, tls_close ),
};
/** TLS ciphertext stream interface descriptor */
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 ( ( rc = x509_check_name ( cert, tls->name ) ) != 0 ) {
DBGC ( tls, "TLS %p server certificate does not match %s: %s\n",
tls, tls->name, strerror ( rc ) );
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 );
if ( tls->cert ) {
tls->tx_pending |= ( TLS_TX_CERTIFICATE |
TLS_TX_CERTIFICATE_VERIFY );
}
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
*
******************************************************************************
*/
/**
* TLS TX state machine
*
* @v tls TLS session
*/
static void tls_tx_step ( struct tls_session *tls ) {
int rc;
/* Wait for cipherstream to become ready */
if ( ! xfer_window ( &tls->cipherstream ) )
return;
/* Send first pending transmission */
if ( tls->tx_pending & TLS_TX_CLIENT_HELLO ) {
/* Send Client Hello */
if ( ( rc = tls_send_client_hello ( tls ) ) != 0 ) {
DBGC ( tls, "TLS %p could not send Client Hello: %s\n",
tls, strerror ( rc ) );
goto err;
}
tls->tx_pending &= ~TLS_TX_CLIENT_HELLO;
} else if ( tls->tx_pending & TLS_TX_CERTIFICATE ) {
/* Send Certificate */
if ( ( rc = tls_send_certificate ( tls ) ) != 0 ) {
DBGC ( tls, "TLS %p cold not send Certificate: %s\n",
tls, strerror ( rc ) );
goto err;
}
tls->tx_pending &= ~TLS_TX_CERTIFICATE;
} else if ( tls->tx_pending & TLS_TX_CLIENT_KEY_EXCHANGE ) {
/* Send Client Key Exchange */
if ( ( rc = tls_send_client_key_exchange ( tls ) ) != 0 ) {
DBGC ( tls, "TLS %p could not send Client Key "
"Exchange: %s\n", tls, strerror ( rc ) );
goto err;
}
tls->tx_pending &= ~TLS_TX_CLIENT_KEY_EXCHANGE;
} else if ( tls->tx_pending & TLS_TX_CERTIFICATE_VERIFY ) {
/* Send Certificate Verify */
if ( ( rc = tls_send_certificate_verify ( tls ) ) != 0 ) {
DBGC ( tls, "TLS %p could not send Certificate "
"Verify: %s\n", tls, strerror ( rc ) );
goto err;
}
tls->tx_pending &= ~TLS_TX_CERTIFICATE_VERIFY;
} else if ( tls->tx_pending & TLS_TX_CHANGE_CIPHER ) {
/* Send Change Cipher, and then change the cipher in use */
if ( ( rc = tls_send_change_cipher ( tls ) ) != 0 ) {
DBGC ( tls, "TLS %p could not send Change Cipher: "
"%s\n", tls, strerror ( rc ) );
goto err;
}
if ( ( rc = tls_change_cipher ( tls,
&tls->tx_cipherspec_pending,
&tls->tx_cipherspec )) != 0 ){
DBGC ( tls, "TLS %p could not activate TX cipher: "
"%s\n", tls, strerror ( rc ) );
goto err;
}
tls->tx_seq = 0;
tls->tx_pending &= ~TLS_TX_CHANGE_CIPHER;
} else if ( tls->tx_pending & TLS_TX_FINISHED ) {
/* Send Finished */
if ( ( rc = tls_send_finished ( tls ) ) != 0 ) {
DBGC ( tls, "TLS %p could not send Finished: %s\n",
tls, strerror ( rc ) );
goto err;
}
tls->tx_pending &= ~TLS_TX_FINISHED;
}
/* Reschedule process if pending transmissions remain */
if ( tls->tx_pending )
tls_tx_resume ( tls );
return;
err:
tls_close ( tls, rc );
}
/** TLS TX process descriptor */
static struct process_descriptor tls_process_desc =
PROC_DESC_ONCE ( struct tls_session, process, tls_tx_step );
/******************************************************************************
*
* Instantiator
*
******************************************************************************
*/
int add_tls ( struct interface *xfer, const char *name,
struct interface **next ) {
struct tls_session *tls;
int rc;
/* Allocate and initialise TLS structure */
tls = malloc ( sizeof ( *tls ) );
if ( ! tls ) {
rc = -ENOMEM;
goto err_alloc;
}
memset ( tls, 0, sizeof ( *tls ) );
ref_init ( &tls->refcnt, free_tls );
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 );
tls_clear_cipher ( tls, &tls->rx_cipherspec );
tls_clear_cipher ( tls, &tls->rx_cipherspec_pending );
tls->client_random.gmt_unix_time = time ( NULL );
if ( ( rc = tls_generate_random ( tls, &tls->client_random.random,
( sizeof ( tls->client_random.random ) ) ) ) != 0 ) {
goto err_random;
}
tls->pre_master_secret.version = htons ( tls->version );
if ( ( rc = tls_generate_random ( tls, &tls->pre_master_secret.random,
( sizeof ( tls->pre_master_secret.random ) ) ) ) != 0 ) {
goto err_random;
}
digest_init ( &md5_sha1_algorithm, tls->handshake_md5_sha1_ctx );
digest_init ( &sha256_algorithm, tls->handshake_sha256_ctx );
tls->handshake_digest = &sha256_algorithm;
tls->handshake_ctx = tls->handshake_sha256_ctx;
tls->tx_pending = TLS_TX_CLIENT_HELLO;
iob_populate ( &tls->rx_header_iobuf, &tls->rx_header, 0,
sizeof ( tls->rx_header ) );
INIT_LIST_HEAD ( &tls->rx_data );
/* Add pending operations for server and client Finished messages */
pending_get ( &tls->client_negotiation );
pending_get ( &tls->server_negotiation );
/* Attach to parent interface, mortalise self, and return */
intf_plug_plug ( &tls->plainstream, xfer );
*next = &tls->cipherstream;
ref_put ( &tls->refcnt );
return 0;
err_random:
ref_put ( &tls->refcnt );
err_alloc:
return rc;
}
/* Drag in objects via add_tls() */
REQUIRING_SYMBOL ( add_tls );
/* Drag in crypto configuration */
REQUIRE_OBJECT ( config_crypto );
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