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M2_SETI/A1/TP/axtls-code/ssl/tls1.c
hiGepi 0b4fc9e542 tp D3
2022-11-28 11:40:47 +01:00

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/*
* Copyright (c) 2007, Cameron Rich
*
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* * Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
* * Neither the name of the axTLS project nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/**
* Common ssl/tlsv1 code to both the client and server implementations.
*/
#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#include <stdarg.h>
#include "os_port.h"
#include "ssl.h"
/* The session expiry time */
#define SSL_EXPIRY_TIME (CONFIG_SSL_EXPIRY_TIME*3600)
static const uint8_t g_hello_request[] = { HS_HELLO_REQUEST, 0, 0, 0 };
static const uint8_t g_chg_cipher_spec_pkt[] = { 1 };
static const char * server_finished = "server finished";
static const char * client_finished = "client finished";
static int do_handshake(SSL *ssl, uint8_t *buf, int read_len);
static int set_key_block(SSL *ssl, int is_write);
static int verify_digest(SSL *ssl, int mode, const uint8_t *buf, int read_len);
static void *crypt_new(SSL *ssl, uint8_t *key, uint8_t *iv, int is_decrypt);
static int send_raw_packet(SSL *ssl, uint8_t protocol);
/**
* The server will pick the cipher based on the order that the order that the
* ciphers are listed. This order is defined at compile time.
*/
#ifndef CONFIG_SSL_SKELETON_MODE
static void session_free(SSL_SESSION *ssl_sessions[], int sess_index);
#endif
const uint8_t ssl_prot_prefs[NUM_PROTOCOLS] =
#ifdef CONFIG_SSL_PROT_LOW /* same as medium for now */
{ SSL_AES128_SHA, SSL_AES256_SHA };
#elif CONFIG_SSL_PROT_MEDIUM /* medium security, medium speed */
{ SSL_AES128_SHA, SSL_AES256_SHA };
#else /* CONFIG_SSL_PROT_HIGH */ /* high security, low speed */
{ SSL_AES256_SHA, SSL_AES128_SHA };
#endif
/**
* The cipher map containing all the essentials for each cipher.
*/
static const cipher_info_t cipher_info[NUM_PROTOCOLS] =
{
{ /* AES128-SHA */
SSL_AES128_SHA, /* AES128-SHA */
16, /* key size */
16, /* iv size */
2*(SHA1_SIZE+16+16), /* key block size */
16, /* block padding size */
SHA1_SIZE, /* digest size */
hmac_sha1, /* hmac algorithm */
(crypt_func)AES_cbc_encrypt, /* encrypt */
(crypt_func)AES_cbc_decrypt /* decrypt */
},
{ /* AES256-SHA */
SSL_AES256_SHA, /* AES256-SHA */
32, /* key size */
16, /* iv size */
2*(SHA1_SIZE+32+16), /* key block size */
16, /* block padding size */
SHA1_SIZE, /* digest size */
hmac_sha1, /* hmac algorithm */
(crypt_func)AES_cbc_encrypt, /* encrypt */
(crypt_func)AES_cbc_decrypt /* decrypt */
},
};
static void prf(const uint8_t *sec, int sec_len, uint8_t *seed, int seed_len,
uint8_t *out, int olen);
static const cipher_info_t *get_cipher_info(uint8_t cipher);
static void increment_read_sequence(SSL *ssl);
static void increment_write_sequence(SSL *ssl);
static void add_hmac_digest(SSL *ssl, int snd, uint8_t *hmac_header,
const uint8_t *buf, int buf_len, uint8_t *hmac_buf);
/* win32 VC6.0 doesn't have variadic macros */
#if defined(WIN32) && !defined(CONFIG_SSL_FULL_MODE)
void DISPLAY_BYTES(SSL *ssl, const char *format,
const uint8_t *data, int size, ...) {}
#endif
/**
* Establish a new client/server context.
*/
EXP_FUNC SSL_CTX *STDCALL ssl_ctx_new(uint32_t options, int num_sessions)
{
SSL_CTX *ssl_ctx = (SSL_CTX *)calloc(1, sizeof (SSL_CTX));
ssl_ctx->options = options;
RNG_initialize();
if (load_key_certs(ssl_ctx) < 0)
{
free(ssl_ctx); /* can't load our key/certificate pair, so die */
return NULL;
}
#ifndef CONFIG_SSL_SKELETON_MODE
ssl_ctx->num_sessions = num_sessions;
#endif
SSL_CTX_MUTEX_INIT(ssl_ctx->mutex);
#ifndef CONFIG_SSL_SKELETON_MODE
if (num_sessions)
{
ssl_ctx->ssl_sessions = (SSL_SESSION **)
calloc(1, num_sessions*sizeof(SSL_SESSION *));
}
#endif
return ssl_ctx;
}
/*
* Remove a client/server context.
*/
EXP_FUNC void STDCALL ssl_ctx_free(SSL_CTX *ssl_ctx)
{
SSL *ssl;
int i;
if (ssl_ctx == NULL)
return;
ssl = ssl_ctx->head;
/* clear out all the ssl entries */
while (ssl)
{
SSL *next = ssl->next;
ssl_free(ssl);
ssl = next;
}
#ifndef CONFIG_SSL_SKELETON_MODE
/* clear out all the sessions */
for (i = 0; i < ssl_ctx->num_sessions; i++)
session_free(ssl_ctx->ssl_sessions, i);
free(ssl_ctx->ssl_sessions);
#endif
i = 0;
while (i < CONFIG_SSL_MAX_CERTS && ssl_ctx->certs[i].buf)
{
free(ssl_ctx->certs[i].buf);
ssl_ctx->certs[i++].buf = NULL;
}
#ifdef CONFIG_SSL_CERT_VERIFICATION
remove_ca_certs(ssl_ctx->ca_cert_ctx);
#endif
ssl_ctx->chain_length = 0;
SSL_CTX_MUTEX_DESTROY(ssl_ctx->mutex);
RSA_free(ssl_ctx->rsa_ctx);
RNG_terminate();
free(ssl_ctx);
}
/*
* Free any used resources used by this connection.
*/
EXP_FUNC void STDCALL ssl_free(SSL *ssl)
{
SSL_CTX *ssl_ctx;
if (ssl == NULL) /* just ignore null pointers */
return;
/* only notify if we weren't notified first */
/* spec says we must notify when we are dying */
if (!IS_SET_SSL_FLAG(SSL_SENT_CLOSE_NOTIFY))
send_alert(ssl, SSL_ALERT_CLOSE_NOTIFY);
ssl_ctx = ssl->ssl_ctx;
SSL_CTX_LOCK(ssl_ctx->mutex);
/* adjust the server SSL list */
if (ssl->prev)
ssl->prev->next = ssl->next;
else
ssl_ctx->head = ssl->next;
if (ssl->next)
ssl->next->prev = ssl->prev;
else
ssl_ctx->tail = ssl->prev;
SSL_CTX_UNLOCK(ssl_ctx->mutex);
/* may already be free - but be sure */
free(ssl->encrypt_ctx);
free(ssl->decrypt_ctx);
disposable_free(ssl);
#ifdef CONFIG_SSL_CERT_VERIFICATION
x509_free(ssl->x509_ctx);
#endif
free(ssl);
}
/*
* Read the SSL connection and send any alerts for various errors.
*/
EXP_FUNC int STDCALL ssl_read(SSL *ssl, uint8_t **in_data)
{
int ret = basic_read(ssl, in_data);
/* check for return code so we can send an alert */
if (ret < SSL_OK && ret != SSL_CLOSE_NOTIFY)
{
if (ret != SSL_ERROR_CONN_LOST)
{
send_alert(ssl, ret);
#ifndef CONFIG_SSL_SKELETON_MODE
/* something nasty happened, so get rid of this session */
kill_ssl_session(ssl->ssl_ctx->ssl_sessions, ssl);
#endif
}
}
return ret;
}
/*
* Write application data to the client
*/
EXP_FUNC int STDCALL ssl_write(SSL *ssl, const uint8_t *out_data, int out_len)
{
int n = out_len, nw, i, tot = 0;
/* maximum size of a TLS packet is around 16kB, so fragment */
do
{
nw = n;
if (nw > RT_MAX_PLAIN_LENGTH) /* fragment if necessary */
nw = RT_MAX_PLAIN_LENGTH;
if ((i = send_packet(ssl, PT_APP_PROTOCOL_DATA,
&out_data[tot], nw)) <= 0)
{
out_len = i; /* an error */
break;
}
tot += i;
n -= i;
} while (n > 0);
return out_len;
}
/**
* Add a certificate to the certificate chain.
*/
int add_cert(SSL_CTX *ssl_ctx, const uint8_t *buf, int len)
{
int ret = SSL_ERROR_NO_CERT_DEFINED, i = 0;
SSL_CERT *ssl_cert;
X509_CTX *cert = NULL;
int offset;
while (i < CONFIG_SSL_MAX_CERTS && ssl_ctx->certs[i].buf)
i++;
if (i == CONFIG_SSL_MAX_CERTS) /* too many certs */
{
#ifdef CONFIG_SSL_FULL_MODE
printf("Error: maximum number of certs added (%d) - change of "
"compile-time configuration required\n",
CONFIG_SSL_MAX_CERTS);
#endif
goto error;
}
if ((ret = x509_new(buf, &offset, &cert)))
goto error;
#if defined (CONFIG_SSL_FULL_MODE)
if (ssl_ctx->options & SSL_DISPLAY_CERTS)
x509_print(cert, NULL);
#endif
ssl_cert = &ssl_ctx->certs[i];
ssl_cert->size = len;
ssl_cert->buf = (uint8_t *)malloc(len);
memcpy(ssl_cert->buf, buf, len);
ssl_ctx->chain_length++;
len -= offset;
ret = SSL_OK; /* ok so far */
/* recurse? */
if (len > 0)
{
ret = add_cert(ssl_ctx, &buf[offset], len);
}
error:
x509_free(cert); /* don't need anymore */
return ret;
}
#ifdef CONFIG_SSL_CERT_VERIFICATION
/**
* Add a certificate authority.
*/
int add_cert_auth(SSL_CTX *ssl_ctx, const uint8_t *buf, int len)
{
int ret = X509_OK; /* ignore errors for now */
int i = 0;
CA_CERT_CTX *ca_cert_ctx;
if (ssl_ctx->ca_cert_ctx == NULL)
ssl_ctx->ca_cert_ctx = (CA_CERT_CTX *)calloc(1, sizeof(CA_CERT_CTX));
ca_cert_ctx = ssl_ctx->ca_cert_ctx;
while (i < CONFIG_X509_MAX_CA_CERTS && ca_cert_ctx->cert[i])
i++;
while (len > 0)
{
int offset;
if (i >= CONFIG_X509_MAX_CA_CERTS)
{
#ifdef CONFIG_SSL_FULL_MODE
printf("Error: maximum number of CA certs added (%d) - change of "
"compile-time configuration required\n",
CONFIG_X509_MAX_CA_CERTS);
#endif
ret = X509_MAX_CERTS;
break;
}
/* ignore the return code */
if (x509_new(buf, &offset, &ca_cert_ctx->cert[i]) == X509_OK)
{
#if defined (CONFIG_SSL_FULL_MODE)
if (ssl_ctx->options & SSL_DISPLAY_CERTS)
x509_print(ca_cert_ctx->cert[i], NULL);
#endif
}
i++;
len -= offset;
}
return ret;
}
/*
* Retrieve an X.509 distinguished name component
*/
EXP_FUNC const char * STDCALL ssl_get_cert_dn(const SSL *ssl, int component)
{
if (ssl->x509_ctx == NULL)
return NULL;
switch (component)
{
case SSL_X509_CERT_COMMON_NAME:
return ssl->x509_ctx->cert_dn[X509_COMMON_NAME];
case SSL_X509_CERT_ORGANIZATION:
return ssl->x509_ctx->cert_dn[X509_ORGANIZATION];
case SSL_X509_CERT_ORGANIZATIONAL_NAME:
return ssl->x509_ctx->cert_dn[X509_ORGANIZATIONAL_UNIT];
case SSL_X509_CA_CERT_COMMON_NAME:
return ssl->x509_ctx->ca_cert_dn[X509_COMMON_NAME];
case SSL_X509_CA_CERT_ORGANIZATION:
return ssl->x509_ctx->ca_cert_dn[X509_ORGANIZATION];
case SSL_X509_CA_CERT_ORGANIZATIONAL_NAME:
return ssl->x509_ctx->ca_cert_dn[X509_ORGANIZATIONAL_UNIT];
default:
return NULL;
}
}
/*
* Retrieve a "Subject Alternative Name" from a v3 certificate
*/
EXP_FUNC const char * STDCALL ssl_get_cert_subject_alt_dnsname(const SSL *ssl,
int dnsindex)
{
int i;
if (ssl->x509_ctx == NULL || ssl->x509_ctx->subject_alt_dnsnames == NULL)
return NULL;
for (i = 0; i < dnsindex; ++i)
{
if (ssl->x509_ctx->subject_alt_dnsnames[i] == NULL)
return NULL;
}
return ssl->x509_ctx->subject_alt_dnsnames[dnsindex];
}
#endif /* CONFIG_SSL_CERT_VERIFICATION */
/*
* Find an ssl object based on the client's file descriptor.
*/
EXP_FUNC SSL * STDCALL ssl_find(SSL_CTX *ssl_ctx, int client_fd)
{
SSL *ssl;
SSL_CTX_LOCK(ssl_ctx->mutex);
ssl = ssl_ctx->head;
/* search through all the ssl entries */
while (ssl)
{
if (ssl->client_fd == client_fd)
{
SSL_CTX_UNLOCK(ssl_ctx->mutex);
return ssl;
}
ssl = ssl->next;
}
SSL_CTX_UNLOCK(ssl_ctx->mutex);
return NULL;
}
/*
* Force the client to perform its handshake again.
*/
EXP_FUNC int STDCALL ssl_renegotiate(SSL *ssl)
{
int ret = SSL_OK;
disposable_new(ssl);
#ifdef CONFIG_SSL_ENABLE_CLIENT
if (IS_SET_SSL_FLAG(SSL_IS_CLIENT))
{
ret = do_client_connect(ssl);
}
else
#endif
{
send_packet(ssl, PT_HANDSHAKE_PROTOCOL,
g_hello_request, sizeof(g_hello_request));
SET_SSL_FLAG(SSL_NEED_RECORD);
}
return ret;
}
/**
* @brief Get what we need for key info.
* @param cipher [in] The cipher information we are after
* @param key_size [out] The key size for the cipher
* @param iv_size [out] The iv size for the cipher
* @return The amount of key information we need.
*/
static const cipher_info_t *get_cipher_info(uint8_t cipher)
{
int i;
for (i = 0; i < NUM_PROTOCOLS; i++)
{
if (cipher_info[i].cipher == cipher)
{
return &cipher_info[i];
}
}
return NULL; /* error */
}
/*
* Get a new ssl context for a new connection.
*/
SSL *ssl_new(SSL_CTX *ssl_ctx, int client_fd)
{
SSL *ssl = (SSL *)calloc(1, sizeof(SSL));
ssl->ssl_ctx = ssl_ctx;
ssl->need_bytes = SSL_RECORD_SIZE; /* need a record */
ssl->client_fd = client_fd;
ssl->flag = SSL_NEED_RECORD;
ssl->bm_data = ssl->bm_all_data+BM_RECORD_OFFSET; /* space at the start */
ssl->hs_status = SSL_NOT_OK; /* not connected */
#ifdef CONFIG_ENABLE_VERIFICATION
ssl->ca_cert_ctx = ssl_ctx->ca_cert_ctx;
#endif
disposable_new(ssl);
/* a bit hacky but saves a few bytes of memory */
ssl->flag |= ssl_ctx->options;
SSL_CTX_LOCK(ssl_ctx->mutex);
if (ssl_ctx->head == NULL)
{
ssl_ctx->head = ssl;
ssl_ctx->tail = ssl;
}
else
{
ssl->prev = ssl_ctx->tail;
ssl_ctx->tail->next = ssl;
ssl_ctx->tail = ssl;
}
SSL_CTX_UNLOCK(ssl_ctx->mutex);
return ssl;
}
/*
* Add a private key to a context.
*/
int add_private_key(SSL_CTX *ssl_ctx, SSLObjLoader *ssl_obj)
{
int ret = SSL_OK;
/* get the private key details */
if (asn1_get_private_key(ssl_obj->buf, ssl_obj->len, &ssl_ctx->rsa_ctx))
{
ret = SSL_ERROR_INVALID_KEY;
goto error;
}
error:
return ret;
}
/**
* Increment the read sequence number (as a 64 bit endian indepenent #)
*/
static void increment_read_sequence(SSL *ssl)
{
int i;
for (i = 7; i >= 0; i--)
{
if (++ssl->read_sequence[i])
break;
}
}
/**
* Increment the read sequence number (as a 64 bit endian indepenent #)
*/
static void increment_write_sequence(SSL *ssl)
{
int i;
for (i = 7; i >= 0; i--)
{
if (++ssl->write_sequence[i])
break;
}
}
/**
* Work out the HMAC digest in a packet.
*/
static void add_hmac_digest(SSL *ssl, int mode, uint8_t *hmac_header,
const uint8_t *buf, int buf_len, uint8_t *hmac_buf)
{
int hmac_len = buf_len + 8 + SSL_RECORD_SIZE;
uint8_t *t_buf = (uint8_t *)alloca(hmac_len+10);
memcpy(t_buf, (mode == SSL_SERVER_WRITE || mode == SSL_CLIENT_WRITE) ?
ssl->write_sequence : ssl->read_sequence, 8);
memcpy(&t_buf[8], hmac_header, SSL_RECORD_SIZE);
memcpy(&t_buf[8+SSL_RECORD_SIZE], buf, buf_len);
ssl->cipher_info->hmac(t_buf, hmac_len,
(mode == SSL_SERVER_WRITE || mode == SSL_CLIENT_READ) ?
ssl->server_mac : ssl->client_mac,
ssl->cipher_info->digest_size, hmac_buf);
#if 0
print_blob("record", hmac_header, SSL_RECORD_SIZE);
print_blob("buf", buf, buf_len);
if (mode == SSL_SERVER_WRITE || mode == SSL_CLIENT_WRITE)
{
print_blob("write seq", ssl->write_sequence, 8);
}
else
{
print_blob("read seq", ssl->read_sequence, 8);
}
if (mode == SSL_SERVER_WRITE || mode == SSL_CLIENT_READ)
{
print_blob("server mac",
ssl->server_mac, ssl->cipher_info->digest_size);
}
else
{
print_blob("client mac",
ssl->client_mac, ssl->cipher_info->digest_size);
}
print_blob("hmac", hmac_buf, SHA1_SIZE);
#endif
}
/**
* Verify that the digest of a packet is correct.
*/
static int verify_digest(SSL *ssl, int mode, const uint8_t *buf, int read_len)
{
uint8_t hmac_buf[SHA1_SIZE];
int hmac_offset;
if (ssl->cipher_info->padding_size)
{
int last_blk_size = buf[read_len-1], i;
hmac_offset = read_len-last_blk_size-ssl->cipher_info->digest_size-1;
/* guard against a timing attack - make sure we do the digest */
if (hmac_offset < 0)
{
hmac_offset = 0;
}
else
{
/* already looked at last byte */
for (i = 1; i < last_blk_size; i++)
{
if (buf[read_len-i] != last_blk_size)
{
hmac_offset = 0;
break;
}
}
}
}
else /* stream cipher */
{
hmac_offset = read_len - ssl->cipher_info->digest_size;
if (hmac_offset < 0)
{
hmac_offset = 0;
}
}
/* sanity check the offset */
ssl->hmac_header[3] = hmac_offset >> 8; /* insert size */
ssl->hmac_header[4] = hmac_offset & 0xff;
add_hmac_digest(ssl, mode, ssl->hmac_header, buf, hmac_offset, hmac_buf);
if (memcmp(hmac_buf, &buf[hmac_offset], ssl->cipher_info->digest_size))
{
return SSL_ERROR_INVALID_HMAC;
}
return hmac_offset;
}
/**
* Add a packet to the end of our sent and received packets, so that we may use
* it to calculate the hash at the end.
*/
void add_packet(SSL *ssl, const uint8_t *pkt, int len)
{
MD5_Update(&ssl->dc->md5_ctx, pkt, len);
SHA1_Update(&ssl->dc->sha1_ctx, pkt, len);
}
/**
* Work out the MD5 PRF.
*/
static void p_hash_md5(const uint8_t *sec, int sec_len,
uint8_t *seed, int seed_len, uint8_t *out, int olen)
{
uint8_t a1[128];
/* A(1) */
hmac_md5(seed, seed_len, sec, sec_len, a1);
memcpy(&a1[MD5_SIZE], seed, seed_len);
hmac_md5(a1, MD5_SIZE+seed_len, sec, sec_len, out);
while (olen > MD5_SIZE)
{
uint8_t a2[MD5_SIZE];
out += MD5_SIZE;
olen -= MD5_SIZE;
/* A(N) */
hmac_md5(a1, MD5_SIZE, sec, sec_len, a2);
memcpy(a1, a2, MD5_SIZE);
/* work out the actual hash */
hmac_md5(a1, MD5_SIZE+seed_len, sec, sec_len, out);
}
}
/**
* Work out the SHA1 PRF.
*/
static void p_hash_sha1(const uint8_t *sec, int sec_len,
uint8_t *seed, int seed_len, uint8_t *out, int olen)
{
uint8_t a1[128];
/* A(1) */
hmac_sha1(seed, seed_len, sec, sec_len, a1);
memcpy(&a1[SHA1_SIZE], seed, seed_len);
hmac_sha1(a1, SHA1_SIZE+seed_len, sec, sec_len, out);
while (olen > SHA1_SIZE)
{
uint8_t a2[SHA1_SIZE];
out += SHA1_SIZE;
olen -= SHA1_SIZE;
/* A(N) */
hmac_sha1(a1, SHA1_SIZE, sec, sec_len, a2);
memcpy(a1, a2, SHA1_SIZE);
/* work out the actual hash */
hmac_sha1(a1, SHA1_SIZE+seed_len, sec, sec_len, out);
}
}
/**
* Work out the PRF.
*/
static void prf(const uint8_t *sec, int sec_len, uint8_t *seed, int seed_len,
uint8_t *out, int olen)
{
int len, i;
const uint8_t *S1, *S2;
uint8_t xbuf[256]; /* needs to be > the amount of key data */
uint8_t ybuf[256]; /* needs to be > the amount of key data */
len = sec_len/2;
S1 = sec;
S2 = &sec[len];
len += (sec_len & 1); /* add for odd, make longer */
p_hash_md5(S1, len, seed, seed_len, xbuf, olen);
p_hash_sha1(S2, len, seed, seed_len, ybuf, olen);
for (i = 0; i < olen; i++)
out[i] = xbuf[i] ^ ybuf[i];
}
/**
* Generate a master secret based on the client/server random data and the
* premaster secret.
*/
void generate_master_secret(SSL *ssl, const uint8_t *premaster_secret)
{
uint8_t buf[128]; /* needs to be > 13+32+32 in size */
strcpy((char *)buf, "master secret");
memcpy(&buf[13], ssl->dc->client_random, SSL_RANDOM_SIZE);
memcpy(&buf[45], ssl->dc->server_random, SSL_RANDOM_SIZE);
prf(premaster_secret, SSL_SECRET_SIZE, buf, 77, ssl->dc->master_secret,
SSL_SECRET_SIZE);
}
/**
* Generate a 'random' blob of data used for the generation of keys.
*/
static void generate_key_block(uint8_t *client_random, uint8_t *server_random,
uint8_t *master_secret, uint8_t *key_block, int key_block_size)
{
uint8_t buf[128];
strcpy((char *)buf, "key expansion");
memcpy(&buf[13], server_random, SSL_RANDOM_SIZE);
memcpy(&buf[45], client_random, SSL_RANDOM_SIZE);
prf(master_secret, SSL_SECRET_SIZE, buf, 77, key_block, key_block_size);
}
/**
* Calculate the digest used in the finished message. This function also
* doubles up as a certificate verify function.
*/
void finished_digest(SSL *ssl, const char *label, uint8_t *digest)
{
uint8_t mac_buf[128];
uint8_t *q = mac_buf;
MD5_CTX md5_ctx = ssl->dc->md5_ctx;
SHA1_CTX sha1_ctx = ssl->dc->sha1_ctx;
if (label)
{
strcpy((char *)q, label);
q += strlen(label);
}
MD5_Final(q, &md5_ctx);
q += MD5_SIZE;
SHA1_Final(q, &sha1_ctx);
q += SHA1_SIZE;
if (label)
{
prf(ssl->dc->master_secret, SSL_SECRET_SIZE, mac_buf, (int)(q-mac_buf),
digest, SSL_FINISHED_HASH_SIZE);
}
else /* for use in a certificate verify */
{
memcpy(digest, mac_buf, MD5_SIZE + SHA1_SIZE);
}
#if 0
printf("label: %s\n", label);
print_blob("master secret", ssl->dc->master_secret, 48);
print_blob("mac_buf", mac_buf, q-mac_buf);
print_blob("finished digest", digest, SSL_FINISHED_HASH_SIZE);
#endif
}
/**
* Retrieve (and initialise) the context of a cipher.
*/
static void *crypt_new(SSL *ssl, uint8_t *key, uint8_t *iv, int is_decrypt)
{
switch (ssl->cipher)
{
case SSL_AES128_SHA:
{
AES_CTX *aes_ctx = (AES_CTX *)malloc(sizeof(AES_CTX));
AES_set_key(aes_ctx, key, iv, AES_MODE_128);
if (is_decrypt)
{
AES_convert_key(aes_ctx);
}
return (void *)aes_ctx;
}
case SSL_AES256_SHA:
{
AES_CTX *aes_ctx = (AES_CTX *)malloc(sizeof(AES_CTX));
AES_set_key(aes_ctx, key, iv, AES_MODE_256);
if (is_decrypt)
{
AES_convert_key(aes_ctx);
}
return (void *)aes_ctx;
}
}
return NULL; /* its all gone wrong */
}
/**
* Send a packet over the socket.
*/
static int send_raw_packet(SSL *ssl, uint8_t protocol)
{
uint8_t *rec_buf = ssl->bm_all_data;
int pkt_size = SSL_RECORD_SIZE+ssl->bm_index;
int sent = 0;
int ret = SSL_OK;
rec_buf[0] = protocol;
rec_buf[1] = 0x03; /* version = 3.1 or higher */
rec_buf[2] = ssl->version & 0x0f;
rec_buf[3] = ssl->bm_index >> 8;
rec_buf[4] = ssl->bm_index & 0xff;
DISPLAY_BYTES(ssl, "sending %d bytes", ssl->bm_all_data,
pkt_size, pkt_size);
while (sent < pkt_size)
{
ret = SOCKET_WRITE(ssl->client_fd,
&ssl->bm_all_data[sent], pkt_size-sent);
if (ret >= 0)
sent += ret;
else
{
#ifdef WIN32
if (GetLastError() != WSAEWOULDBLOCK)
#else
if (errno != EAGAIN && errno != EWOULDBLOCK)
#endif
return SSL_ERROR_CONN_LOST;
}
/* keep going until the write buffer has some space */
if (sent != pkt_size)
{
fd_set wfds;
FD_ZERO(&wfds);
FD_SET(ssl->client_fd, &wfds);
/* block and wait for it */
if (select(ssl->client_fd + 1, NULL, &wfds, NULL, NULL) < 0)
return SSL_ERROR_CONN_LOST;
}
}
SET_SSL_FLAG(SSL_NEED_RECORD); /* reset for next time */
ssl->bm_index = 0;
if (protocol != PT_APP_PROTOCOL_DATA)
{
/* always return SSL_OK during handshake */
ret = SSL_OK;
}
return ret;
}
/**
* Send an encrypted packet with padding bytes if necessary.
*/
int send_packet(SSL *ssl, uint8_t protocol, const uint8_t *in, int length)
{
int ret, msg_length = 0;
/* if our state is bad, don't bother */
if (ssl->hs_status == SSL_ERROR_DEAD)
return SSL_ERROR_CONN_LOST;
if (in) /* has the buffer already been initialised? */
{
memcpy(ssl->bm_data, in, length);
}
msg_length += length;
if (IS_SET_SSL_FLAG(SSL_TX_ENCRYPTED))
{
int mode = IS_SET_SSL_FLAG(SSL_IS_CLIENT) ?
SSL_CLIENT_WRITE : SSL_SERVER_WRITE;
uint8_t hmac_header[SSL_RECORD_SIZE] =
{
protocol,
0x03, /* version = 3.1 or higher */
ssl->version & 0x0f,
msg_length >> 8,
msg_length & 0xff
};
if (protocol == PT_HANDSHAKE_PROTOCOL)
{
DISPLAY_STATE(ssl, 1, ssl->bm_data[0], 0);
if (ssl->bm_data[0] != HS_HELLO_REQUEST)
{
add_packet(ssl, ssl->bm_data, msg_length);
}
}
/* add the packet digest */
add_hmac_digest(ssl, mode, hmac_header, ssl->bm_data, msg_length,
&ssl->bm_data[msg_length]);
msg_length += ssl->cipher_info->digest_size;
/* add padding? */
if (ssl->cipher_info->padding_size)
{
int last_blk_size = msg_length%ssl->cipher_info->padding_size;
int pad_bytes = ssl->cipher_info->padding_size - last_blk_size;
/* ensure we always have at least 1 padding byte */
if (pad_bytes == 0)
pad_bytes += ssl->cipher_info->padding_size;
memset(&ssl->bm_data[msg_length], pad_bytes-1, pad_bytes);
msg_length += pad_bytes;
}
DISPLAY_BYTES(ssl, "unencrypted write", ssl->bm_data, msg_length);
increment_write_sequence(ssl);
/* add the explicit IV for TLS1.1 */
if (ssl->version >= SSL_PROTOCOL_VERSION1_1 &&
ssl->cipher_info->iv_size)
{
uint8_t iv_size = ssl->cipher_info->iv_size;
uint8_t *t_buf = alloca(msg_length + iv_size);
memcpy(t_buf + iv_size, ssl->bm_data, msg_length);
if (get_random(iv_size, t_buf) < 0)
return SSL_NOT_OK;
msg_length += iv_size;
memcpy(ssl->bm_data, t_buf, msg_length);
}
/* now encrypt the packet */
ssl->cipher_info->encrypt(ssl->encrypt_ctx, ssl->bm_data,
ssl->bm_data, msg_length);
}
else if (protocol == PT_HANDSHAKE_PROTOCOL)
{
DISPLAY_STATE(ssl, 1, ssl->bm_data[0], 0);
if (ssl->bm_data[0] != HS_HELLO_REQUEST)
{
add_packet(ssl, ssl->bm_data, length);
}
}
ssl->bm_index = msg_length;
if ((ret = send_raw_packet(ssl, protocol)) <= 0)
return ret;
return length; /* just return what we wanted to send */
}
/**
* Work out the cipher keys we are going to use for this session based on the
* master secret.
*/
static int set_key_block(SSL *ssl, int is_write)
{
const cipher_info_t *ciph_info = get_cipher_info(ssl->cipher);
uint8_t *q;
uint8_t client_key[32], server_key[32]; /* big enough for AES256 */
uint8_t client_iv[16], server_iv[16]; /* big enough for AES128/256 */
int is_client = IS_SET_SSL_FLAG(SSL_IS_CLIENT);
if (ciph_info == NULL)
return -1;
/* only do once in a handshake */
if (ssl->dc->key_block == NULL)
{
ssl->dc->key_block = (uint8_t *)malloc(ciph_info->key_block_size);
#if 0
print_blob("client", ssl->dc->client_random, 32);
print_blob("server", ssl->dc->server_random, 32);
print_blob("master", ssl->dc->master_secret, SSL_SECRET_SIZE);
#endif
generate_key_block(ssl->dc->client_random, ssl->dc->server_random,
ssl->dc->master_secret, ssl->dc->key_block,
ciph_info->key_block_size);
#if 0
print_blob("keyblock", ssl->dc->key_block, ciph_info->key_block_size);
#endif
}
q = ssl->dc->key_block;
if ((is_client && is_write) || (!is_client && !is_write))
{
memcpy(ssl->client_mac, q, ciph_info->digest_size);
}
q += ciph_info->digest_size;
if ((!is_client && is_write) || (is_client && !is_write))
{
memcpy(ssl->server_mac, q, ciph_info->digest_size);
}
q += ciph_info->digest_size;
memcpy(client_key, q, ciph_info->key_size);
q += ciph_info->key_size;
memcpy(server_key, q, ciph_info->key_size);
q += ciph_info->key_size;
if (ciph_info->iv_size) /* RC4 has no IV, AES does */
{
memcpy(client_iv, q, ciph_info->iv_size);
q += ciph_info->iv_size;
memcpy(server_iv, q, ciph_info->iv_size);
q += ciph_info->iv_size;
}
free(is_write ? ssl->encrypt_ctx : ssl->decrypt_ctx);
/* now initialise the ciphers */
if (is_client)
{
finished_digest(ssl, server_finished, ssl->dc->final_finish_mac);
if (is_write)
ssl->encrypt_ctx = crypt_new(ssl, client_key, client_iv, 0);
else
ssl->decrypt_ctx = crypt_new(ssl, server_key, server_iv, 1);
}
else
{
finished_digest(ssl, client_finished, ssl->dc->final_finish_mac);
if (is_write)
ssl->encrypt_ctx = crypt_new(ssl, server_key, server_iv, 0);
else
ssl->decrypt_ctx = crypt_new(ssl, client_key, client_iv, 1);
}
ssl->cipher_info = ciph_info;
return 0;
}
/**
* Read the SSL connection.
*/
int basic_read(SSL *ssl, uint8_t **in_data)
{
int ret = SSL_OK;
int read_len, is_client = IS_SET_SSL_FLAG(SSL_IS_CLIENT);
uint8_t *buf = ssl->bm_data;
read_len = SOCKET_READ(ssl->client_fd, &buf[ssl->bm_read_index],
ssl->need_bytes-ssl->got_bytes);
if (read_len < 0)
{
#ifdef WIN32
if (GetLastError() == WSAEWOULDBLOCK)
#else
if (errno == EAGAIN || errno == EWOULDBLOCK)
#endif
return 0;
}
/* connection has gone, so die */
if (read_len <= 0)
{
ret = SSL_ERROR_CONN_LOST;
ssl->hs_status = SSL_ERROR_DEAD; /* make sure it stays dead */
goto error;
}
DISPLAY_BYTES(ssl, "received %d bytes",
&ssl->bm_data[ssl->bm_read_index], read_len, read_len);
ssl->got_bytes += read_len;
ssl->bm_read_index += read_len;
/* haven't quite got what we want, so try again later */
if (ssl->got_bytes < ssl->need_bytes)
return SSL_OK;
read_len = ssl->got_bytes;
ssl->got_bytes = 0;
if (IS_SET_SSL_FLAG(SSL_NEED_RECORD))
{
/* check for sslv2 "client hello" */
if (buf[0] & 0x80 && buf[2] == 1)
{
#ifdef CONFIG_SSL_FULL_MODE
printf("Error: no SSLv23 handshaking allowed\n");
#endif
ret = SSL_ERROR_NOT_SUPPORTED;
goto error; /* not an error - just get out of here */
}
ssl->need_bytes = (buf[3] << 8) + buf[4];
/* do we violate the spec with the message size? */
if (ssl->need_bytes > RT_MAX_PLAIN_LENGTH+RT_EXTRA-BM_RECORD_OFFSET)
{
ret = SSL_ERROR_INVALID_PROT_MSG;
goto error;
}
CLR_SSL_FLAG(SSL_NEED_RECORD);
memcpy(ssl->hmac_header, buf, 3); /* store for hmac */
ssl->record_type = buf[0];
goto error; /* no error, we're done */
}
/* for next time - just do it now in case of an error */
SET_SSL_FLAG(SSL_NEED_RECORD);
ssl->need_bytes = SSL_RECORD_SIZE;
/* decrypt if we need to */
if (IS_SET_SSL_FLAG(SSL_RX_ENCRYPTED))
{
ssl->cipher_info->decrypt(ssl->decrypt_ctx, buf, buf, read_len);
if (ssl->version >= SSL_PROTOCOL_VERSION1_1 &&
ssl->cipher_info->iv_size)
{
buf += ssl->cipher_info->iv_size;
read_len -= ssl->cipher_info->iv_size;
}
read_len = verify_digest(ssl,
is_client ? SSL_CLIENT_READ : SSL_SERVER_READ, buf, read_len);
/* does the hmac work? */
if (read_len < 0)
{
ret = read_len;
goto error;
}
DISPLAY_BYTES(ssl, "decrypted", buf, read_len);
increment_read_sequence(ssl);
}
/* The main part of the SSL packet */
switch (ssl->record_type)
{
case PT_HANDSHAKE_PROTOCOL:
if (ssl->dc != NULL)
{
ssl->dc->bm_proc_index = 0;
ret = do_handshake(ssl, buf, read_len);
}
else /* no client renegotiation allowed */
{
ret = SSL_ERROR_NO_CLIENT_RENOG;
goto error;
}
break;
case PT_CHANGE_CIPHER_SPEC:
if (ssl->next_state != HS_FINISHED)
{
ret = SSL_ERROR_INVALID_HANDSHAKE;
goto error;
}
if (set_key_block(ssl, 0) < 0)
{
ret = SSL_ERROR_INVALID_HANDSHAKE;
goto error;
}
/* all encrypted from now on */
SET_SSL_FLAG(SSL_RX_ENCRYPTED);
memset(ssl->read_sequence, 0, 8);
break;
case PT_APP_PROTOCOL_DATA:
if (in_data && ssl->hs_status == SSL_OK)
{
*in_data = buf; /* point to the work buffer */
(*in_data)[read_len] = 0; /* null terminate just in case */
ret = read_len;
}
else
ret = SSL_ERROR_INVALID_PROT_MSG;
break;
case PT_ALERT_PROTOCOL:
/* return the alert # with alert bit set */
if(buf[0] == SSL_ALERT_TYPE_WARNING &&
buf[1] == SSL_ALERT_CLOSE_NOTIFY)
{
ret = SSL_CLOSE_NOTIFY;
send_alert(ssl, SSL_ALERT_CLOSE_NOTIFY);
SET_SSL_FLAG(SSL_SENT_CLOSE_NOTIFY);
}
else
{
ret = -buf[1];
DISPLAY_ALERT(ssl, buf[1]);
}
break;
default:
ret = SSL_ERROR_INVALID_PROT_MSG;
break;
}
error:
ssl->bm_read_index = 0; /* reset to go again */
if (ret < SSL_OK && in_data)/* if all wrong, then clear this buffer ptr */
*in_data = NULL;
return ret;
}
/**
* Do some basic checking of data and then perform the appropriate handshaking.
*/
static int do_handshake(SSL *ssl, uint8_t *buf, int read_len)
{
int hs_len = (buf[2]<<8) + buf[3];
uint8_t handshake_type = buf[0];
int ret = SSL_OK;
int is_client = IS_SET_SSL_FLAG(SSL_IS_CLIENT);
/* some integrity checking on the handshake */
PARANOIA_CHECK(read_len-SSL_HS_HDR_SIZE, hs_len);
if (handshake_type != ssl->next_state)
{
/* handle a special case on the client */
if (!is_client || handshake_type != HS_CERT_REQ ||
ssl->next_state != HS_SERVER_HELLO_DONE)
{
ret = SSL_ERROR_INVALID_HANDSHAKE;
goto error;
}
}
hs_len += SSL_HS_HDR_SIZE; /* adjust for when adding packets */
ssl->bm_index = hs_len; /* store the size and check later */
DISPLAY_STATE(ssl, 0, handshake_type, 0);
if (handshake_type != HS_CERT_VERIFY && handshake_type != HS_HELLO_REQUEST)
add_packet(ssl, buf, hs_len);
#if defined(CONFIG_SSL_ENABLE_CLIENT)
ret = is_client ?
do_clnt_handshake(ssl, handshake_type, buf, hs_len) :
do_svr_handshake(ssl, handshake_type, buf, hs_len);
#else
ret = do_svr_handshake(ssl, handshake_type, buf, hs_len);
#endif
/* just use recursion to get the rest */
if (hs_len < read_len && ret == SSL_OK)
ret = do_handshake(ssl, &buf[hs_len], read_len-hs_len);
error:
return ret;
}
/**
* Sends the change cipher spec message. We have just read a finished message
* from the client.
*/
int send_change_cipher_spec(SSL *ssl)
{
int ret = send_packet(ssl, PT_CHANGE_CIPHER_SPEC,
g_chg_cipher_spec_pkt, sizeof(g_chg_cipher_spec_pkt));
if (ret >= 0 && set_key_block(ssl, 1) < 0)
ret = SSL_ERROR_INVALID_HANDSHAKE;
if (ssl->cipher_info)
SET_SSL_FLAG(SSL_TX_ENCRYPTED);
memset(ssl->write_sequence, 0, 8);
return ret;
}
/**
* Send a "finished" message
*/
int send_finished(SSL *ssl)
{
uint8_t buf[SSL_FINISHED_HASH_SIZE+4] = {
HS_FINISHED, 0, 0, SSL_FINISHED_HASH_SIZE };
/* now add the finished digest mac (12 bytes) */
finished_digest(ssl,
IS_SET_SSL_FLAG(SSL_IS_CLIENT) ?
client_finished : server_finished, &buf[4]);
#ifndef CONFIG_SSL_SKELETON_MODE
/* store in the session cache */
if (!IS_SET_SSL_FLAG(SSL_SESSION_RESUME) && ssl->ssl_ctx->num_sessions)
{
memcpy(ssl->session->master_secret,
ssl->dc->master_secret, SSL_SECRET_SIZE);
}
#endif
return send_packet(ssl, PT_HANDSHAKE_PROTOCOL,
buf, SSL_FINISHED_HASH_SIZE+4);
}
/**
* Send an alert message.
* Return 1 if the alert was an "error".
*/
int send_alert(SSL *ssl, int error_code)
{
int alert_num = 0;
int is_warning = 0;
uint8_t buf[2];
/* Don't bother we're already dead */
if (ssl->hs_status == SSL_ERROR_DEAD)
{
return SSL_ERROR_CONN_LOST;
}
#ifdef CONFIG_SSL_FULL_MODE
if (IS_SET_SSL_FLAG(SSL_DISPLAY_STATES))
ssl_display_error(error_code);
#endif
switch (error_code)
{
case SSL_ALERT_CLOSE_NOTIFY:
is_warning = 1;
alert_num = SSL_ALERT_CLOSE_NOTIFY;
break;
case SSL_ERROR_CONN_LOST: /* don't send alert just yet */
is_warning = 1;
break;
case SSL_ERROR_INVALID_HANDSHAKE:
case SSL_ERROR_INVALID_PROT_MSG:
alert_num = SSL_ALERT_HANDSHAKE_FAILURE;
break;
case SSL_ERROR_INVALID_HMAC:
case SSL_ERROR_FINISHED_INVALID:
alert_num = SSL_ALERT_BAD_RECORD_MAC;
break;
case SSL_ERROR_INVALID_VERSION:
alert_num = SSL_ALERT_INVALID_VERSION;
break;
case SSL_ERROR_INVALID_SESSION:
case SSL_ERROR_NO_CIPHER:
case SSL_ERROR_INVALID_KEY:
alert_num = SSL_ALERT_ILLEGAL_PARAMETER;
break;
case SSL_ERROR_BAD_CERTIFICATE:
alert_num = SSL_ALERT_BAD_CERTIFICATE;
break;
case SSL_ERROR_NO_CLIENT_RENOG:
alert_num = SSL_ALERT_NO_RENEGOTIATION;
break;
default:
/* a catch-all for any badly verified certificates */
alert_num = (error_code <= SSL_X509_OFFSET) ?
SSL_ALERT_BAD_CERTIFICATE : SSL_ALERT_UNEXPECTED_MESSAGE;
break;
}
buf[0] = is_warning ? 1 : 2;
buf[1] = alert_num;
send_packet(ssl, PT_ALERT_PROTOCOL, buf, sizeof(buf));
DISPLAY_ALERT(ssl, alert_num);
return is_warning ? 0 : 1;
}
/**
* Process a client finished message.
*/
int process_finished(SSL *ssl, uint8_t *buf, int hs_len)
{
int ret = SSL_OK;
int is_client = IS_SET_SSL_FLAG(SSL_IS_CLIENT);
int resume = IS_SET_SSL_FLAG(SSL_SESSION_RESUME);
PARANOIA_CHECK(ssl->bm_index, SSL_FINISHED_HASH_SIZE+4);
/* check that we all work before we continue */
if (memcmp(ssl->dc->final_finish_mac, &buf[4], SSL_FINISHED_HASH_SIZE))
return SSL_ERROR_FINISHED_INVALID;
if ((!is_client && !resume) || (is_client && resume))
{
if ((ret = send_change_cipher_spec(ssl)) == SSL_OK)
ret = send_finished(ssl);
}
/* if we ever renegotiate */
ssl->next_state = is_client ? HS_HELLO_REQUEST : HS_CLIENT_HELLO;
ssl->hs_status = ret; /* set the final handshake status */
error:
return ret;
}
/**
* Send a certificate.
*/
int send_certificate(SSL *ssl)
{
int i = 0;
uint8_t *buf = ssl->bm_data;
int offset = 7;
int chain_length;
buf[0] = HS_CERTIFICATE;
buf[1] = 0;
buf[4] = 0;
while (i < ssl->ssl_ctx->chain_length)
{
SSL_CERT *cert = &ssl->ssl_ctx->certs[i];
buf[offset++] = 0;
buf[offset++] = cert->size >> 8; /* cert 1 length */
buf[offset++] = cert->size & 0xff;
memcpy(&buf[offset], cert->buf, cert->size);
offset += cert->size;
i++;
}
chain_length = offset - 7;
buf[5] = chain_length >> 8; /* cert chain length */
buf[6] = chain_length & 0xff;
chain_length += 3;
buf[2] = chain_length >> 8; /* handshake length */
buf[3] = chain_length & 0xff;
ssl->bm_index = offset;
return send_packet(ssl, PT_HANDSHAKE_PROTOCOL, NULL, offset);
}
/**
* Create a blob of memory that we'll get rid of once the handshake is
* complete.
*/
void disposable_new(SSL *ssl)
{
if (ssl->dc == NULL)
{
ssl->dc = (DISPOSABLE_CTX *)calloc(1, sizeof(DISPOSABLE_CTX));
MD5_Init(&ssl->dc->md5_ctx);
SHA1_Init(&ssl->dc->sha1_ctx);
}
}
/**
* Remove the temporary blob of memory.
*/
void disposable_free(SSL *ssl)
{
if (ssl->dc)
{
free(ssl->dc->key_block);
memset(ssl->dc, 0, sizeof(DISPOSABLE_CTX));
free(ssl->dc);
ssl->dc = NULL;
}
}
#ifndef CONFIG_SSL_SKELETON_MODE /* no session resumption in this mode */
/**
* Find if an existing session has the same session id. If so, use the
* master secret from this session for session resumption.
*/
SSL_SESSION *ssl_session_update(int max_sessions, SSL_SESSION *ssl_sessions[],
SSL *ssl, const uint8_t *session_id)
{
time_t tm = time(NULL);
time_t oldest_sess_time = tm;
SSL_SESSION *oldest_sess = NULL;
int i;
/* no sessions? Then bail */
if (max_sessions == 0)
return NULL;
SSL_CTX_LOCK(ssl->ssl_ctx->mutex);
if (session_id)
{
for (i = 0; i < max_sessions; i++)
{
if (ssl_sessions[i])
{
/* kill off any expired sessions (including those in
the future) */
if ((tm > ssl_sessions[i]->conn_time + SSL_EXPIRY_TIME) ||
(tm < ssl_sessions[i]->conn_time))
{
session_free(ssl_sessions, i);
continue;
}
/* if the session id matches, it must still be less than
the expiry time */
if (memcmp(ssl_sessions[i]->session_id, session_id,
SSL_SESSION_ID_SIZE) == 0)
{
ssl->session_index = i;
memcpy(ssl->dc->master_secret,
ssl_sessions[i]->master_secret, SSL_SECRET_SIZE);
SET_SSL_FLAG(SSL_SESSION_RESUME);
SSL_CTX_UNLOCK(ssl->ssl_ctx->mutex);
return ssl_sessions[i]; /* a session was found */
}
}
}
}
/* If we've got here, no matching session was found - so create one */
for (i = 0; i < max_sessions; i++)
{
if (ssl_sessions[i] == NULL)
{
/* perfect, this will do */
ssl_sessions[i] = (SSL_SESSION *)calloc(1, sizeof(SSL_SESSION));
ssl_sessions[i]->conn_time = tm;
ssl->session_index = i;
SSL_CTX_UNLOCK(ssl->ssl_ctx->mutex);
return ssl_sessions[i]; /* return the session object */
}
else if (ssl_sessions[i]->conn_time <= oldest_sess_time)
{
/* find the oldest session */
oldest_sess_time = ssl_sessions[i]->conn_time;
oldest_sess = ssl_sessions[i];
ssl->session_index = i;
}
}
/* ok, we've used up all of our sessions. So blow the oldest session away */
oldest_sess->conn_time = tm;
memset(oldest_sess->session_id, 0, SSL_SESSION_ID_SIZE);
memset(oldest_sess->master_secret, 0, SSL_SECRET_SIZE);
SSL_CTX_UNLOCK(ssl->ssl_ctx->mutex);
return oldest_sess;
}
/**
* Free an existing session.
*/
static void session_free(SSL_SESSION *ssl_sessions[], int sess_index)
{
if (ssl_sessions[sess_index])
{
free(ssl_sessions[sess_index]);
ssl_sessions[sess_index] = NULL;
}
}
/**
* This ssl object doesn't want this session anymore.
*/
void kill_ssl_session(SSL_SESSION **ssl_sessions, SSL *ssl)
{
SSL_CTX_LOCK(ssl->ssl_ctx->mutex);
if (ssl->ssl_ctx->num_sessions)
{
session_free(ssl_sessions, ssl->session_index);
ssl->session = NULL;
}
SSL_CTX_UNLOCK(ssl->ssl_ctx->mutex);
}
#endif /* CONFIG_SSL_SKELETON_MODE */
/*
* Get the session id for a handshake. This will be a 32 byte sequence.
*/
EXP_FUNC const uint8_t * STDCALL ssl_get_session_id(const SSL *ssl)
{
return ssl->session_id;
}
/*
* Get the session id size for a handshake.
*/
EXP_FUNC uint8_t STDCALL ssl_get_session_id_size(const SSL *ssl)
{
return ssl->sess_id_size;
}
/*
* Return the cipher id (in the SSL form).
*/
EXP_FUNC uint8_t STDCALL ssl_get_cipher_id(const SSL *ssl)
{
return ssl->cipher;
}
/*
* Return the status of the handshake.
*/
EXP_FUNC int STDCALL ssl_handshake_status(const SSL *ssl)
{
return ssl->hs_status;
}
/*
* Retrieve various parameters about the SSL engine.
*/
EXP_FUNC int STDCALL ssl_get_config(int offset)
{
switch (offset)
{
/* return the appropriate build mode */
case SSL_BUILD_MODE:
#if defined(CONFIG_SSL_FULL_MODE)
return SSL_BUILD_FULL_MODE;
#elif defined(CONFIG_SSL_ENABLE_CLIENT)
return SSL_BUILD_ENABLE_CLIENT;
#elif defined(CONFIG_ENABLE_VERIFICATION)
return SSL_BUILD_ENABLE_VERIFICATION;
#elif defined(CONFIG_SSL_SERVER_ONLY )
return SSL_BUILD_SERVER_ONLY;
#else
return SSL_BUILD_SKELETON_MODE;
#endif
case SSL_MAX_CERT_CFG_OFFSET:
return CONFIG_SSL_MAX_CERTS;
#ifdef CONFIG_SSL_CERT_VERIFICATION
case SSL_MAX_CA_CERT_CFG_OFFSET:
return CONFIG_X509_MAX_CA_CERTS;
#endif
#ifdef CONFIG_SSL_HAS_PEM
case SSL_HAS_PEM:
return 1;
#endif
default:
return 0;
}
}
#ifdef CONFIG_SSL_CERT_VERIFICATION
/**
* Authenticate a received certificate.
*/
EXP_FUNC int STDCALL ssl_verify_cert(const SSL *ssl)
{
int ret;
SSL_CTX_LOCK(ssl->ssl_ctx->mutex);
ret = x509_verify(ssl->ssl_ctx->ca_cert_ctx, ssl->x509_ctx);
SSL_CTX_UNLOCK(ssl->ssl_ctx->mutex);
if (ret) /* modify into an SSL error type */
{
ret = SSL_X509_ERROR(ret);
}
return ret;
}
/**
* Process a certificate message.
*/
int process_certificate(SSL *ssl, X509_CTX **x509_ctx)
{
int ret = SSL_OK;
uint8_t *buf = &ssl->bm_data[ssl->dc->bm_proc_index];
int pkt_size = ssl->bm_index;
int cert_size, offset = 5, offset_start;
int total_cert_size = (buf[offset]<<8) + buf[offset+1];
int is_client = IS_SET_SSL_FLAG(SSL_IS_CLIENT);
X509_CTX *chain = 0;
X509_CTX **certs = 0;
int *cert_used = 0;
int num_certs = 0;
int i = 0;
offset += 2;
PARANOIA_CHECK(total_cert_size, offset);
// record the start point for the second pass
offset_start = offset;
// first pass - count the certificates
while (offset < total_cert_size)
{
offset++; /* skip empty char */
cert_size = (buf[offset]<<8) + buf[offset+1];
offset += 2;
offset += cert_size;
num_certs++;
}
PARANOIA_CHECK(pkt_size, offset);
certs = (X509_CTX**) calloc(num_certs, sizeof(void*));
cert_used = (int*) calloc(num_certs, sizeof(int));
num_certs = 0;
// restore the offset from the saved value
offset = offset_start;
// second pass - load the certificates
while (offset < total_cert_size)
{
offset++; /* skip empty char */
cert_size = (buf[offset]<<8) + buf[offset+1];
offset += 2;
if (x509_new(&buf[offset], NULL, certs+num_certs))
{
ret = SSL_ERROR_BAD_CERTIFICATE;
goto error;
}
num_certs++;
offset += cert_size;
}
PARANOIA_CHECK(pkt_size, offset);
// third pass - link certs together, assume server cert is the first
*x509_ctx = certs[0];
chain = certs[0];
cert_used[0] = 1;
// repeat until the end of the chain is found
while (1)
{
// look for CA cert
for( i = 1; i < num_certs; i++ )
{
if (certs[i] == chain)
continue;
if (cert_used[i])
continue; // don't allow loops
if (asn1_compare_dn(chain->ca_cert_dn, certs[i]->cert_dn) == 0)
{
// CA cert found, add it to the chain
cert_used[i] = 1;
chain->next = certs[i];
chain = certs[i];
break;
}
}
// no CA cert found, reached the end of the chain
if (i >= num_certs)
break;
}
// clean up any certs that aren't part of the chain
for (i = 1; i < num_certs; i++)
{
if (cert_used[i] == 0)
x509_free(certs[i]);
}
/* if we are client we can do the verify now or later */
if (is_client && !IS_SET_SSL_FLAG(SSL_SERVER_VERIFY_LATER))
{
ret = ssl_verify_cert(ssl);
}
ssl->next_state = is_client ? HS_SERVER_HELLO_DONE : HS_CLIENT_KEY_XCHG;
ssl->dc->bm_proc_index += offset;
error:
// clean up arrays
if (certs)
free(certs);
if (cert_used)
free(cert_used);
return ret;
}
#endif /* CONFIG_SSL_CERT_VERIFICATION */
/**
* Debugging routine to display SSL handshaking stuff.
*/
#ifdef CONFIG_SSL_FULL_MODE
/**
* Debugging routine to display SSL states.
*/
void DISPLAY_STATE(SSL *ssl, int is_send, uint8_t state, int not_ok)
{
const char *str;
if (!IS_SET_SSL_FLAG(SSL_DISPLAY_STATES))
return;
printf(not_ok ? "Error - invalid State:\t" : "State:\t");
printf(is_send ? "sending " : "receiving ");
switch (state)
{
case HS_HELLO_REQUEST:
str = "Hello Request (0)";
break;
case HS_CLIENT_HELLO:
str = "Client Hello (1)";
break;
case HS_SERVER_HELLO:
str = "Server Hello (2)";
break;
case HS_CERTIFICATE:
str = "Certificate (11)";
break;
case HS_SERVER_KEY_XCHG:
str = "Certificate Request (12)";
break;
case HS_CERT_REQ:
str = "Certificate Request (13)";
break;
case HS_SERVER_HELLO_DONE:
str = "Server Hello Done (14)";
break;
case HS_CERT_VERIFY:
str = "Certificate Verify (15)";
break;
case HS_CLIENT_KEY_XCHG:
str = "Client Key Exchange (16)";
break;
case HS_FINISHED:
str = "Finished (16)";
break;
default:
str = "Error (Unknown)";
break;
}
printf("%s\n", str);
}
/**
* Debugging routine to display RSA objects
*/
void DISPLAY_RSA(SSL *ssl, const RSA_CTX *rsa_ctx)
{
if (!IS_SET_SSL_FLAG(SSL_DISPLAY_RSA))
return;
RSA_print(rsa_ctx);
TTY_FLUSH();
}
/**
* Debugging routine to display SSL handshaking bytes.
*/
void DISPLAY_BYTES(SSL *ssl, const char *format,
const uint8_t *data, int size, ...)
{
va_list(ap);
if (!IS_SET_SSL_FLAG(SSL_DISPLAY_BYTES))
return;
va_start(ap, size);
print_blob(format, data, size, va_arg(ap, char *));
va_end(ap);
TTY_FLUSH();
}
/**
* Debugging routine to display SSL handshaking errors.
*/
EXP_FUNC void STDCALL ssl_display_error(int error_code)
{
if (error_code == SSL_OK)
return;
printf("Error: ");
/* X509 error? */
if (error_code < SSL_X509_OFFSET)
{
printf("%s\n", x509_display_error(error_code - SSL_X509_OFFSET));
return;
}
/* SSL alert error code */
if (error_code > SSL_ERROR_CONN_LOST)
{
printf("SSL error %d\n", -error_code);
return;
}
switch (error_code)
{
case SSL_ERROR_DEAD:
printf("connection dead");
break;
case SSL_ERROR_INVALID_HANDSHAKE:
printf("invalid handshake");
break;
case SSL_ERROR_INVALID_PROT_MSG:
printf("invalid protocol message");
break;
case SSL_ERROR_INVALID_HMAC:
printf("invalid mac");
break;
case SSL_ERROR_INVALID_VERSION:
printf("invalid version");
break;
case SSL_ERROR_INVALID_SESSION:
printf("invalid session");
break;
case SSL_ERROR_NO_CIPHER:
printf("no cipher");
break;
case SSL_ERROR_CONN_LOST:
printf("connection lost");
break;
case SSL_ERROR_BAD_CERTIFICATE:
printf("bad certificate");
break;
case SSL_ERROR_INVALID_KEY:
printf("invalid key");
break;
case SSL_ERROR_FINISHED_INVALID:
printf("finished invalid");
break;
case SSL_ERROR_NO_CERT_DEFINED:
printf("no certificate defined");
break;
case SSL_ERROR_NO_CLIENT_RENOG:
printf("client renegotiation not supported");
break;
case SSL_ERROR_NOT_SUPPORTED:
printf("Option not supported");
break;
default:
printf("undefined as yet - %d", error_code);
break;
}
printf("\n");
}
/**
* Debugging routine to display alerts.
*/
void DISPLAY_ALERT(SSL *ssl, int alert)
{
if (!IS_SET_SSL_FLAG(SSL_DISPLAY_STATES))
return;
printf("Alert: ");
switch (alert)
{
case SSL_ALERT_CLOSE_NOTIFY:
printf("close notify");
break;
case SSL_ALERT_INVALID_VERSION:
printf("invalid version");
break;
case SSL_ALERT_BAD_CERTIFICATE:
printf("bad certificate");
break;
case SSL_ALERT_UNEXPECTED_MESSAGE:
printf("unexpected message");
break;
case SSL_ALERT_BAD_RECORD_MAC:
printf("bad record mac");
break;
case SSL_ALERT_HANDSHAKE_FAILURE:
printf("handshake failure");
break;
case SSL_ALERT_ILLEGAL_PARAMETER:
printf("illegal parameter");
break;
case SSL_ALERT_DECODE_ERROR:
printf("decode error");
break;
case SSL_ALERT_DECRYPT_ERROR:
printf("decrypt error");
break;
case SSL_ALERT_NO_RENEGOTIATION:
printf("no renegotiation");
break;
default:
printf("alert - (unknown %d)", alert);
break;
}
printf("\n");
}
#endif /* CONFIG_SSL_FULL_MODE */
/**
* Return the version of this library.
*/
EXP_FUNC const char * STDCALL ssl_version()
{
static const char * axtls_version = AXTLS_VERSION;
return axtls_version;
}
/**
* Enable the various language bindings to work regardless of the
* configuration - they just return an error statement and a bad return code.
*/
#if !defined(CONFIG_SSL_FULL_MODE)
EXP_FUNC void STDCALL ssl_display_error(int error_code) {}
#endif
#ifdef CONFIG_BINDINGS
#if !defined(CONFIG_SSL_ENABLE_CLIENT)
EXP_FUNC SSL * STDCALL ssl_client_new(SSL_CTX *ssl_ctx, int client_fd, const
uint8_t *session_id, uint8_t sess_id_size)
{
printf("%s", unsupported_str);
return NULL;
}
#endif
#if !defined(CONFIG_SSL_CERT_VERIFICATION)
EXP_FUNC int STDCALL ssl_verify_cert(const SSL *ssl)
{
printf("%s", unsupported_str);
return -1;
}
EXP_FUNC const char * STDCALL ssl_get_cert_dn(const SSL *ssl, int component)
{
printf("%s", unsupported_str);
return NULL;
}
EXP_FUNC const char * STDCALL ssl_get_cert_subject_alt_dnsname(const SSL *ssl, int index)
{
printf("%s", unsupported_str);
return NULL;
}
#endif /* CONFIG_SSL_CERT_VERIFICATION */
#endif /* CONFIG_BINDINGS */
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