tls1_change_cipher_state rewrite

The previous version of the function made adding AEAD changes very
difficult. This change should be a semantic no-op - it should be purely
a cleanup.
This commit is contained in:
Adam Langley 2014-06-20 12:00:00 -07:00
parent 1b9d47735c
commit a5fa5b7bb6
3 changed files with 203 additions and 192 deletions

View File

@ -2657,6 +2657,7 @@ void ERR_load_SSL_strings(void);
#define SSL_F_ssl3_get_channel_id 275
#define SSL_F_ssl3_send_channel_id 276
#define SSL_F_SSL_CTX_set_cipher_list_tls11 277
#define SSL_F_tls1_change_cipher_state_cipher 278
#define SSL_R_UNABLE_TO_FIND_ECDH_PARAMETERS 100
#define SSL_R_DECRYPTION_FAILED_OR_BAD_RECORD_MAC 101
#define SSL_R_INVALID_NULL_CMD_NAME 102

View File

@ -190,6 +190,7 @@ const ERR_STRING_DATA SSL_error_string_data[] = {
{ERR_PACK(ERR_LIB_SSL, SSL_F_tls1_PRF, 0), "tls1_PRF"},
{ERR_PACK(ERR_LIB_SSL, SSL_F_tls1_cert_verify_mac, 0), "tls1_cert_verify_mac"},
{ERR_PACK(ERR_LIB_SSL, SSL_F_tls1_change_cipher_state, 0), "tls1_change_cipher_state"},
{ERR_PACK(ERR_LIB_SSL, SSL_F_tls1_change_cipher_state_cipher, 0), "tls1_change_cipher_state_cipher"},
{ERR_PACK(ERR_LIB_SSL, SSL_F_tls1_export_keying_material, 0), "tls1_export_keying_material"},
{ERR_PACK(ERR_LIB_SSL, SSL_F_tls1_get_server_supplemental_data, 0), "tls1_get_server_supplemental_data"},
{ERR_PACK(ERR_LIB_SSL, SSL_F_tls1_heartbeat, 0), "tls1_heartbeat"},

View File

@ -311,70 +311,46 @@ static int tls1_generate_key_block(SSL *s, unsigned char *km,
return ret;
}
int tls1_change_cipher_state(SSL *s, int which)
/* tls1_change_cipher_state_cipher performs the work needed to switch cipher
* states when using EVP_CIPHER. The argument |is_read| is true iff this
* function is being called due to reading, as opposed to writing, a
* ChangeCipherSpec message. In order to support export ciphersuites,
* use_client_keys indicates whether the key material provided is in the
* "client write" direction. */
static int tls1_change_cipher_state_cipher(
SSL *s, char is_read, char use_client_keys,
const unsigned char *mac_secret, unsigned mac_secret_len,
const unsigned char *key, unsigned key_len,
const unsigned char *iv, unsigned iv_len)
{
static const unsigned char empty[]="";
unsigned char *p,*mac_secret;
unsigned char *exp_label;
unsigned char tmp1[EVP_MAX_KEY_LENGTH];
unsigned char tmp2[EVP_MAX_KEY_LENGTH];
unsigned char iv1[EVP_MAX_IV_LENGTH*2];
unsigned char iv2[EVP_MAX_IV_LENGTH*2];
unsigned char *ms,*key,*iv;
int client_write;
EVP_CIPHER_CTX *dd;
const EVP_CIPHER *c;
const EVP_MD *m;
int mac_type;
int *mac_secret_size;
const EVP_CIPHER *cipher = s->s3->tmp.new_sym_enc;
const char is_export = SSL_C_IS_EXPORT(s->s3->tmp.new_cipher) != 0;
EVP_CIPHER_CTX *cipher_ctx;
EVP_MD_CTX *mac_ctx;
EVP_PKEY *mac_key;
int is_export,n,i,j,k,exp_label_len,cl;
int reuse_dd = 0;
char is_aead_cipher;
is_export=SSL_C_IS_EXPORT(s->s3->tmp.new_cipher);
c=s->s3->tmp.new_sym_enc;
m=s->s3->tmp.new_hash;
mac_type = s->s3->tmp.new_mac_pkey_type;
unsigned char export_tmp1[EVP_MAX_KEY_LENGTH];
unsigned char export_tmp2[EVP_MAX_KEY_LENGTH];
unsigned char export_iv1[EVP_MAX_IV_LENGTH * 2];
unsigned char export_iv2[EVP_MAX_IV_LENGTH * 2];
#ifdef KSSL_DEBUG
printf("tls1_change_cipher_state(which= %d) w/\n", which);
printf("\talg= %ld/%ld, comp= %p\n",
s->s3->tmp.new_cipher->algorithm_mkey,
s->s3->tmp.new_cipher->algorithm_auth,
comp);
printf("\tevp_cipher == %p ==? &d_cbc_ede_cipher3\n", c);
printf("\tevp_cipher: nid, blksz= %d, %d, keylen=%d, ivlen=%d\n",
c->nid,c->block_size,c->key_len,c->iv_len);
printf("\tkey_block: len= %d, data= ", s->s3->tmp.key_block_length);
{
int i;
for (i=0; i<s->s3->tmp.key_block_length; i++)
printf("%02x", s->s3->tmp.key_block[i]); printf("\n");
}
#endif /* KSSL_DEBUG */
if (which & SSL3_CC_READ)
if (is_read)
{
if (s->s3->tmp.new_cipher->algorithm2 & TLS1_STREAM_MAC)
s->mac_flags |= SSL_MAC_FLAG_READ_MAC_STREAM;
else
s->mac_flags &= ~SSL_MAC_FLAG_READ_MAC_STREAM;
if (s->enc_read_ctx != NULL)
reuse_dd = 1;
else if ((s->enc_read_ctx=OPENSSL_malloc(sizeof(EVP_CIPHER_CTX))) == NULL)
if (s->enc_read_ctx != NULL && !SSL_IS_DTLS(s))
EVP_CIPHER_CTX_cleanup(s->enc_read_ctx);
else if ((s->enc_read_ctx=EVP_CIPHER_CTX_new()) == NULL)
goto err;
else
/* make sure it's intialized in case we exit later with an error */
EVP_CIPHER_CTX_init(s->enc_read_ctx);
dd= s->enc_read_ctx;
mac_ctx=ssl_replace_hash(&s->read_hash,NULL);
/* this is done by dtls1_reset_seq_numbers for DTLS1_VERSION */
if (s->version != DTLS1_VERSION)
memset(&(s->s3->read_sequence[0]),0,8);
mac_secret= &(s->s3->read_mac_secret[0]);
mac_secret_size=&(s->s3->read_mac_secret_size);
cipher_ctx = s->enc_read_ctx;
mac_ctx = ssl_replace_hash(&s->read_hash, NULL);
memcpy(s->s3->read_mac_secret, mac_secret, mac_secret_len);
s->s3->read_mac_secret_size = mac_secret_len;
}
else
{
@ -382,178 +358,205 @@ int tls1_change_cipher_state(SSL *s, int which)
s->mac_flags |= SSL_MAC_FLAG_WRITE_MAC_STREAM;
else
s->mac_flags &= ~SSL_MAC_FLAG_WRITE_MAC_STREAM;
/* When updating the write contexts for DTLS, we do not wish to
* free the old ones because DTLS stores pointers to them in
* order to implement retransmission. */
if (s->enc_write_ctx != NULL && !SSL_IS_DTLS(s))
reuse_dd = 1;
else if ((s->enc_write_ctx=EVP_CIPHER_CTX_new()) == NULL)
EVP_CIPHER_CTX_cleanup(s->enc_write_ctx);
else if ((s->enc_write_ctx=OPENSSL_malloc(sizeof(EVP_CIPHER_CTX))) == NULL)
goto err;
dd= s->enc_write_ctx;
else
/* make sure it's intialized in case we exit later with an error */
EVP_CIPHER_CTX_init(s->enc_write_ctx);
cipher_ctx = s->enc_write_ctx;
if (SSL_IS_DTLS(s))
{
/* This is the same as ssl_replace_hash, but doesn't
* free the old |s->write_hash|. */
mac_ctx = EVP_MD_CTX_create();
if (!mac_ctx)
goto err;
s->write_hash = mac_ctx;
}
else
mac_ctx = ssl_replace_hash(&s->write_hash,NULL);
/* this is done by dtls1_reset_seq_numbers for DTLS1_VERSION */
if (s->version != DTLS1_VERSION)
memset(&(s->s3->write_sequence[0]),0,8);
mac_secret= &(s->s3->write_mac_secret[0]);
mac_secret_size = &(s->s3->write_mac_secret_size);
mac_ctx = ssl_replace_hash(&s->write_hash, NULL);
memcpy(s->s3->write_mac_secret, mac_secret, mac_secret_len);
s->s3->write_mac_secret_size = mac_secret_len;
}
if (reuse_dd)
EVP_CIPHER_CTX_cleanup(dd);
p=s->s3->tmp.key_block;
i=*mac_secret_size=s->s3->tmp.new_mac_secret_size;
cl=EVP_CIPHER_key_length(c);
j=is_export ? (cl < SSL_C_EXPORT_KEYLENGTH(s->s3->tmp.new_cipher) ?
cl : SSL_C_EXPORT_KEYLENGTH(s->s3->tmp.new_cipher)) : cl;
/* Was j=(exp)?5:EVP_CIPHER_key_length(c); */
/* If GCM mode only part of IV comes from PRF */
if (EVP_CIPHER_mode(c) == EVP_CIPH_GCM_MODE)
k = EVP_GCM_TLS_FIXED_IV_LEN;
else
k=EVP_CIPHER_iv_length(c);
if ( (which == SSL3_CHANGE_CIPHER_CLIENT_WRITE) ||
(which == SSL3_CHANGE_CIPHER_SERVER_READ))
{
ms= &(p[ 0]); n=i+i;
key= &(p[ n]); n+=j+j;
iv= &(p[ n]); n+=k+k;
exp_label=(unsigned char *)TLS_MD_CLIENT_WRITE_KEY_CONST;
exp_label_len=TLS_MD_CLIENT_WRITE_KEY_CONST_SIZE;
client_write=1;
}
else
{
n=i;
ms= &(p[ n]); n+=i+j;
key= &(p[ n]); n+=j+k;
iv= &(p[ n]); n+=k;
exp_label=(unsigned char *)TLS_MD_SERVER_WRITE_KEY_CONST;
exp_label_len=TLS_MD_SERVER_WRITE_KEY_CONST_SIZE;
client_write=0;
}
if (n > s->s3->tmp.key_block_length)
{
OPENSSL_PUT_ERROR(SSL, tls1_change_cipher_state, ERR_R_INTERNAL_ERROR);
goto err2;
}
memcpy(mac_secret,ms,i);
if (!(EVP_CIPHER_flags(c)&EVP_CIPH_FLAG_AEAD_CIPHER))
{
mac_key = EVP_PKEY_new_mac_key(mac_type, NULL,
mac_secret,*mac_secret_size);
EVP_DigestSignInit(mac_ctx,NULL,m,NULL,mac_key);
EVP_PKEY_free(mac_key);
}
#ifdef TLS_DEBUG
printf("which = %04X\nmac key=",which);
{ int z; for (z=0; z<i; z++) printf("%02X%c",ms[z],((z+1)%16)?' ':'\n'); }
#endif
if (is_export)
{
/* In here I set both the read and write key/iv to the
* same value since only the correct one will be used :-).
*/
if (!tls1_PRF(ssl_get_algorithm2(s),
exp_label,exp_label_len,
s->s3->client_random,SSL3_RANDOM_SIZE,
s->s3->server_random,SSL3_RANDOM_SIZE,
NULL,0,NULL,0,
key,j,tmp1,tmp2,EVP_CIPHER_key_length(c)))
goto err2;
key=tmp1;
const unsigned char *label;
unsigned label_len;
if (k > 0)
if (use_client_keys)
{
if (!tls1_PRF(ssl_get_algorithm2(s),
TLS_MD_IV_BLOCK_CONST,TLS_MD_IV_BLOCK_CONST_SIZE,
s->s3->client_random,SSL3_RANDOM_SIZE,
s->s3->server_random,SSL3_RANDOM_SIZE,
NULL,0,NULL,0,
empty,0,iv1,iv2,k*2))
goto err2;
if (client_write)
iv=iv1;
else
iv= &(iv1[k]);
}
}
s->session->key_arg_length=0;
#ifdef KSSL_DEBUG
{
int i;
printf("EVP_CipherInit_ex(dd,c,key=,iv=,which)\n");
printf("\tkey= "); for (i=0; i<c->key_len; i++) printf("%02x", key[i]);
printf("\n");
printf("\t iv= "); for (i=0; i<c->iv_len; i++) printf("%02x", iv[i]);
printf("\n");
}
#endif /* KSSL_DEBUG */
if (EVP_CIPHER_mode(c) == EVP_CIPH_GCM_MODE)
{
EVP_CipherInit_ex(dd,c,NULL,key,NULL,(which & SSL3_CC_WRITE));
EVP_CIPHER_CTX_ctrl(dd, EVP_CTRL_GCM_SET_IV_FIXED, k, iv);
label = (const unsigned char*) TLS_MD_CLIENT_WRITE_KEY_CONST;
label_len = TLS_MD_CLIENT_WRITE_KEY_CONST_SIZE;
}
else
EVP_CipherInit_ex(dd,c,NULL,key,iv,(which & SSL3_CC_WRITE));
{
label = (const unsigned char*) TLS_MD_SERVER_WRITE_KEY_CONST;
label_len = TLS_MD_SERVER_WRITE_KEY_CONST_SIZE;
}
if (!tls1_PRF(ssl_get_algorithm2(s),
label, label_len,
s->s3->client_random, SSL3_RANDOM_SIZE,
s->s3->server_random, SSL3_RANDOM_SIZE,
NULL, 0, NULL, 0,
key /* secret */, key_len /* secret length */,
export_tmp1 /* output */,
export_tmp2 /* scratch space */,
EVP_CIPHER_key_length(s->s3->tmp.new_sym_enc) /* output length */))
return 0;
key = export_tmp1;
if (iv_len > 0)
{
static const unsigned char empty[] = "";
if (!tls1_PRF(ssl_get_algorithm2(s),
TLS_MD_IV_BLOCK_CONST, TLS_MD_IV_BLOCK_CONST_SIZE,
s->s3->client_random, SSL3_RANDOM_SIZE,
s->s3->server_random, SSL3_RANDOM_SIZE,
NULL, 0, NULL, 0,
empty /* secret */ ,0 /* secret length */,
export_iv1 /* output */,
export_iv2 /* scratch space */,
iv_len * 2 /* output length */))
return 0;
if (use_client_keys)
iv = export_iv1;
else
iv = &export_iv1[iv_len];
}
}
/* is_aead_cipher indicates whether the EVP_CIPHER implements an AEAD
* interface. This is different from the newer EVP_AEAD interface. */
is_aead_cipher = (EVP_CIPHER_flags(cipher) & EVP_CIPH_FLAG_AEAD_CIPHER) != 0;
if (!is_aead_cipher)
{
EVP_PKEY *mac_key =
EVP_PKEY_new_mac_key(s->s3->tmp.new_mac_pkey_type,
NULL, mac_secret, mac_secret_len);
if (!mac_key)
return 0;
EVP_DigestSignInit(mac_ctx, NULL, s->s3->tmp.new_hash, NULL, mac_key);
EVP_PKEY_free(mac_key);
}
if (EVP_CIPHER_mode(cipher) == EVP_CIPH_GCM_MODE)
{
EVP_CipherInit_ex(cipher_ctx, cipher, NULL /* engine */, key,
NULL /* iv */, !is_read);
EVP_CIPHER_CTX_ctrl(cipher_ctx, EVP_CTRL_GCM_SET_IV_FIXED, iv_len, (void*) iv);
}
else
EVP_CipherInit_ex(cipher_ctx, cipher, NULL /* engine */, key, iv, !is_read);
/* Needed for "composite" AEADs, such as RC4-HMAC-MD5 */
if ((EVP_CIPHER_flags(c)&EVP_CIPH_FLAG_AEAD_CIPHER) && *mac_secret_size)
EVP_CIPHER_CTX_ctrl(dd,EVP_CTRL_AEAD_SET_MAC_KEY,
*mac_secret_size,mac_secret);
if (is_aead_cipher && mac_secret_len > 0)
EVP_CIPHER_CTX_ctrl(cipher_ctx, EVP_CTRL_AEAD_SET_MAC_KEY,
mac_secret_len, (void*) mac_secret);
#ifdef OPENSSL_SSL_TRACE_CRYPTO
if (s->msg_callback)
if (is_export)
{
int wh = which & SSL3_CC_WRITE ? TLS1_RT_CRYPTO_WRITE : 0;
if (*mac_secret_size)
s->msg_callback(2, s->version, wh | TLS1_RT_CRYPTO_MAC,
mac_secret, *mac_secret_size,
s, s->msg_callback_arg);
if (c->key_len)
s->msg_callback(2, s->version, wh | TLS1_RT_CRYPTO_KEY,
key, c->key_len,
s, s->msg_callback_arg);
if (k)
{
if (EVP_CIPHER_mode(c) == EVP_CIPH_GCM_MODE)
wh |= TLS1_RT_CRYPTO_FIXED_IV;
else
wh |= TLS1_RT_CRYPTO_IV;
s->msg_callback(2, s->version, wh, iv, k,
s, s->msg_callback_arg);
OPENSSL_cleanse(export_tmp1, sizeof(export_tmp1));
OPENSSL_cleanse(export_tmp2, sizeof(export_tmp1));
OPENSSL_cleanse(export_iv1, sizeof(export_iv1));
OPENSSL_cleanse(export_iv2, sizeof(export_iv2));
}
}
#endif
#ifdef TLS_DEBUG
printf("which = %04X\nkey=",which);
{ int z; for (z=0; z<EVP_CIPHER_key_length(c); z++) printf("%02X%c",key[z],((z+1)%16)?' ':'\n'); }
printf("\niv=");
{ int z; for (z=0; z<k; z++) printf("%02X%c",iv[z],((z+1)%16)?' ':'\n'); }
printf("\n");
#endif
return 1;
OPENSSL_cleanse(tmp1,sizeof(tmp1));
OPENSSL_cleanse(tmp2,sizeof(tmp1));
OPENSSL_cleanse(iv1,sizeof(iv1));
OPENSSL_cleanse(iv2,sizeof(iv2));
return(1);
err:
OPENSSL_PUT_ERROR(SSL, tls1_change_cipher_state, ERR_R_MALLOC_FAILURE);
err2:
return(0);
OPENSSL_PUT_ERROR(SSL, tls1_change_cipher_state_cipher, ERR_R_MALLOC_FAILURE);
return 0;
}
int tls1_change_cipher_state(SSL *s, int which)
{
/* is_read is true if we have just read a ChangeCipherSpec message -
* i.e. we need to update the read cipherspec. Otherwise we have just
* written one. */
const char is_read = (which & SSL3_CC_READ) != 0;
/* use_client_keys is true if we wish to use the keys for the "client
* write" direction. This is the case if we're a client sending a
* ChangeCipherSpec, or a server reading a client's ChangeCipherSpec. */
const char use_client_keys = which == SSL3_CHANGE_CIPHER_CLIENT_WRITE ||
which == SSL3_CHANGE_CIPHER_SERVER_READ;
const unsigned char *client_write_mac_secret, *server_write_mac_secret, *mac_secret;
const unsigned char *client_write_key, *server_write_key, *key;
const unsigned char *client_write_iv, *server_write_iv, *iv;
const EVP_CIPHER *cipher = s->s3->tmp.new_sym_enc;
unsigned key_len, iv_len, mac_secret_len;
const unsigned char *key_data;
const char is_export = SSL_C_IS_EXPORT(s->s3->tmp.new_cipher) != 0;
/* Reset sequence number to zero. */
if (s->version != DTLS1_VERSION)
memset(is_read ? s->s3->read_sequence : s->s3->write_sequence, 0, 8);
/* key_arg is used for SSLv2. We don't need it for TLS. */
s->session->key_arg_length = 0;
mac_secret_len = s->s3->tmp.new_mac_secret_size;
key_len = EVP_CIPHER_key_length(cipher);
if (is_export && key_len > SSL_C_EXPORT_KEYLENGTH(s->s3->tmp.new_cipher))
key_len = SSL_C_EXPORT_KEYLENGTH(s->s3->tmp.new_cipher);
if (EVP_CIPHER_mode(cipher) == EVP_CIPH_GCM_MODE)
iv_len = EVP_GCM_TLS_FIXED_IV_LEN;
else
iv_len = EVP_CIPHER_iv_length(cipher);
key_data = s->s3->tmp.key_block;
client_write_mac_secret = key_data; key_data += mac_secret_len;
server_write_mac_secret = key_data; key_data += mac_secret_len;
client_write_key = key_data; key_data += key_len;
server_write_key = key_data; key_data += key_len;
client_write_iv = key_data; key_data += iv_len;
server_write_iv = key_data; key_data += iv_len;
if (use_client_keys)
{
mac_secret = client_write_mac_secret;
key = client_write_key;
iv = client_write_iv;
}
else
{
mac_secret = server_write_mac_secret;
key = server_write_key;
iv = server_write_iv;
}
if (key_data - s->s3->tmp.key_block != s->s3->tmp.key_block_length)
{
OPENSSL_PUT_ERROR(SSL, tls1_change_cipher_state, ERR_R_INTERNAL_ERROR);
return 0;
}
if (!tls1_change_cipher_state_cipher(s, is_read, use_client_keys,
mac_secret, mac_secret_len,
key, key_len,
iv, iv_len)) {
return 0;
}
return 1;
}
int tls1_setup_key_block(SSL *s)
@ -565,6 +568,7 @@ int tls1_setup_key_block(SSL *s)
SSL_COMP *comp;
int mac_type= NID_undef,mac_secret_size=0;
int ret=0;
int iv_len;
#ifdef KSSL_DEBUG
printf ("tls1_setup_key_block()\n");
@ -579,11 +583,16 @@ int tls1_setup_key_block(SSL *s)
return(0);
}
if (EVP_CIPHER_mode(c) == EVP_CIPH_GCM_MODE)
iv_len = EVP_GCM_TLS_FIXED_IV_LEN;
else
iv_len = EVP_CIPHER_iv_length(c);
s->s3->tmp.new_sym_enc=c;
s->s3->tmp.new_hash=hash;
s->s3->tmp.new_mac_pkey_type = mac_type;
s->s3->tmp.new_mac_secret_size = mac_secret_size;
num=EVP_CIPHER_key_length(c)+mac_secret_size+EVP_CIPHER_iv_length(c);
num=EVP_CIPHER_key_length(c)+mac_secret_size+iv_len;
num*=2;
ssl3_cleanup_key_block(s);