tls: can download kernels now :)
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko
parent
1500b3a50d
commit
89193f985b
@ -721,7 +721,7 @@ typedef struct tls_state {
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int ofd;
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int ifd;
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int min_encrypted_len_on_read;
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unsigned min_encrypted_len_on_read;
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uint16_t cipher_id;
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uint8_t encrypt_on_write;
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unsigned MAC_size;
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168
networking/tls.c
168
networking/tls.c
@ -53,15 +53,14 @@
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// ok: openssl s_client -connect cdn.kernel.org:443 -debug -tls1_2 -no_tls1 -no_tls1_1 -cipher AES128-SHA
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// (TLS_RSA_WITH_AES_128_CBC_SHA - in TLS 1.2 it's mandated to be always supported)
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#define CIPHER_ID1 TLS_RSA_WITH_AES_256_CBC_SHA256 // no SERVER_KEY_EXCHANGE from peer
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// Does not work yet:
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//#define CIPHER_ID2 TLS_RSA_WITH_AES_128_CBC_SHA
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#define CIPHER_ID2 0
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// Works with "wget https://cdn.kernel.org/pub/linux/kernel/v4.x/linux-4.9.5.tar.xz"
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#define CIPHER_ID2 TLS_RSA_WITH_AES_128_CBC_SHA
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#define TLS_DEBUG 1
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#define TLS_DEBUG_HASH 1
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#define TLS_DEBUG_DER 1
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#define TLS_DEBUG_FIXED_SECRETS 1
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#define TLS_DEBUG 0
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#define TLS_DEBUG_HASH 0
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#define TLS_DEBUG_DER 0
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#define TLS_DEBUG_FIXED_SECRETS 0
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#if 0
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# define dump_raw_out(...) dump_hex(__VA_ARGS__)
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#else
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@ -340,50 +339,80 @@ static void hash_handshake(tls_state_t *tls, const char *fmt, const void *buffer
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// if we often need HMAC hmac with the same key.
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//
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// text is often given in disjoint pieces.
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static unsigned hmac_sha_precomputed_v(uint8_t *out,
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md5sha_ctx_t *hashed_key_xor_ipad,
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md5sha_ctx_t *hashed_key_xor_opad,
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typedef struct hmac_precomputed {
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md5sha_ctx_t hashed_key_xor_ipad;
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md5sha_ctx_t hashed_key_xor_opad;
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} hmac_precomputed_t;
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static unsigned hmac_sha_precomputed_v(
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hmac_precomputed_t *pre,
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uint8_t *out,
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va_list va)
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{
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uint8_t *text;
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unsigned len;
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/* hashed_key_xor_ipad contains unclosed "H((key XOR ipad) +" state */
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/* hashed_key_xor_opad contains unclosed "H((key XOR opad) +" state */
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/* pre->hashed_key_xor_ipad contains unclosed "H((key XOR ipad) +" state */
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/* pre->hashed_key_xor_opad contains unclosed "H((key XOR opad) +" state */
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/* calculate out = H((key XOR ipad) + text) */
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while ((text = va_arg(va, uint8_t*)) != NULL) {
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unsigned text_size = va_arg(va, unsigned);
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md5sha_hash(hashed_key_xor_ipad, text, text_size);
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md5sha_hash(&pre->hashed_key_xor_ipad, text, text_size);
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}
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len = sha_end(hashed_key_xor_ipad, out);
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len = sha_end(&pre->hashed_key_xor_ipad, out);
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/* out = H((key XOR opad) + out) */
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md5sha_hash(hashed_key_xor_opad, out, len);
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return sha_end(hashed_key_xor_opad, out);
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md5sha_hash(&pre->hashed_key_xor_opad, out, len);
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return sha_end(&pre->hashed_key_xor_opad, out);
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}
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static unsigned hmac(tls_state_t *tls, uint8_t *out, uint8_t *key, unsigned key_size, ...)
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static void hmac_sha256_begin(hmac_precomputed_t *pre, uint8_t *key, unsigned key_size)
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{
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md5sha_ctx_t hashed_key_xor_ipad;
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md5sha_ctx_t hashed_key_xor_opad;
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uint8_t key_xor_ipad[SHA_INSIZE];
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uint8_t key_xor_opad[SHA_INSIZE];
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uint8_t tempkey[SHA256_OUTSIZE];
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va_list va;
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unsigned i;
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va_start(va, key_size);
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// "The authentication key can be of any length up to INSIZE, the
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// block length of the hash function. Applications that use keys longer
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// than INSIZE bytes will first hash the key using H and then use the
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// resultant OUTSIZE byte string as the actual key to HMAC."
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if (key_size > SHA_INSIZE) {
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md5sha_ctx_t ctx;
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if (tls->MAC_size == SHA256_OUTSIZE)
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sha256_begin(&ctx);
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else
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md5sha_hash(&ctx, key, key_size);
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key_size = sha_end(&ctx, tempkey);
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}
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for (i = 0; i < key_size; i++) {
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key_xor_ipad[i] = key[i] ^ 0x36;
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key_xor_opad[i] = key[i] ^ 0x5c;
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}
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for (; i < SHA_INSIZE; i++) {
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key_xor_ipad[i] = 0x36;
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key_xor_opad[i] = 0x5c;
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}
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sha256_begin(&pre->hashed_key_xor_ipad);
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sha256_begin(&pre->hashed_key_xor_opad);
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md5sha_hash(&pre->hashed_key_xor_ipad, key_xor_ipad, SHA_INSIZE);
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md5sha_hash(&pre->hashed_key_xor_opad, key_xor_opad, SHA_INSIZE);
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}
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// TODO: ^^^ vvv merge?
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static void hmac_sha1_begin(hmac_precomputed_t *pre, uint8_t *key, unsigned key_size)
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{
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uint8_t key_xor_ipad[SHA_INSIZE];
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uint8_t key_xor_opad[SHA_INSIZE];
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uint8_t tempkey[SHA1_OUTSIZE];
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unsigned i;
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// "The authentication key can be of any length up to INSIZE, the
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// block length of the hash function. Applications that use keys longer
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// than INSIZE bytes will first hash the key using H and then use the
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// resultant OUTSIZE byte string as the actual key to HMAC."
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if (key_size > SHA_INSIZE) {
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md5sha_ctx_t ctx;
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sha1_begin(&ctx);
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md5sha_hash(&ctx, key, key_size);
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key_size = sha_end(&ctx, tempkey);
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@ -398,19 +427,44 @@ static unsigned hmac(tls_state_t *tls, uint8_t *out, uint8_t *key, unsigned key_
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key_xor_opad[i] = 0x5c;
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}
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if (tls->MAC_size == SHA256_OUTSIZE) {
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sha256_begin(&hashed_key_xor_ipad);
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sha256_begin(&hashed_key_xor_opad);
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} else {
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sha1_begin(&hashed_key_xor_ipad);
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sha1_begin(&hashed_key_xor_opad);
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sha1_begin(&pre->hashed_key_xor_ipad);
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sha1_begin(&pre->hashed_key_xor_opad);
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md5sha_hash(&pre->hashed_key_xor_ipad, key_xor_ipad, SHA_INSIZE);
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md5sha_hash(&pre->hashed_key_xor_opad, key_xor_opad, SHA_INSIZE);
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}
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md5sha_hash(&hashed_key_xor_ipad, key_xor_ipad, SHA_INSIZE);
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md5sha_hash(&hashed_key_xor_opad, key_xor_opad, SHA_INSIZE);
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i = hmac_sha_precomputed_v(out, &hashed_key_xor_ipad, &hashed_key_xor_opad, va);
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static unsigned hmac(tls_state_t *tls, uint8_t *out, uint8_t *key, unsigned key_size, ...)
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{
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hmac_precomputed_t pre;
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va_list va;
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unsigned len;
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va_start(va, key_size);
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if (tls->MAC_size == SHA256_OUTSIZE)
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hmac_sha256_begin(&pre, key, key_size);
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else
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hmac_sha1_begin(&pre, key, key_size);
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len = hmac_sha_precomputed_v(&pre, out, va);
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va_end(va);
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return i;
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return len;
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}
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static unsigned hmac_sha256(/*tls_state_t *tls,*/ uint8_t *out, uint8_t *key, unsigned key_size, ...)
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{
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hmac_precomputed_t pre;
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va_list va;
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unsigned len;
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va_start(va, key_size);
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hmac_sha256_begin(&pre, key, key_size);
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len = hmac_sha_precomputed_v(&pre, out, va);
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va_end(va);
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return len;
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}
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// RFC 5246:
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@ -420,6 +474,9 @@ static unsigned hmac(tls_state_t *tls, uint8_t *out, uint8_t *key, unsigned key_
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// SHA-256 hash function is used for all cipher suites defined in this
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// document and in TLS documents published prior to this document when
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// TLS 1.2 is negotiated.
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// ^^^^^^^^^^^^^ IMPORTANT!
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// PRF uses sha256 regardless of cipher (at least for all ciphers
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// defined by RFC5246). It's not sha1 for AES_128_CBC_SHA!
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//...
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// P_hash(secret, seed) = HMAC_hash(secret, A(1) + seed) +
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// HMAC_hash(secret, A(2) + seed) +
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@ -441,7 +498,7 @@ static unsigned hmac(tls_state_t *tls, uint8_t *out, uint8_t *key, unsigned key_
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// PRF(secret, label, seed) = P_<hash>(secret, label + seed)
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//
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// The label is an ASCII string.
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static void prf_hmac(tls_state_t *tls,
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static void prf_hmac_sha256(/*tls_state_t *tls,*/
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uint8_t *outbuf, unsigned outbuf_size,
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uint8_t *secret, unsigned secret_size,
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const char *label,
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@ -450,7 +507,7 @@ static void prf_hmac(tls_state_t *tls,
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uint8_t a[TLS_MAX_MAC_SIZE];
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uint8_t *out_p = outbuf;
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unsigned label_size = strlen(label);
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unsigned MAC_size = tls->MAC_size;
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unsigned MAC_size = SHA256_OUTSIZE;///tls->MAC_size;
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/* In P_hash() calculation, "seed" is "label + seed": */
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#define SEED label, label_size, seed, seed_size
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@ -458,7 +515,7 @@ static void prf_hmac(tls_state_t *tls,
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#define A a, MAC_size
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/* A(1) = HMAC_hash(secret, seed) */
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hmac(tls, a, SECRET, SEED, NULL);
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hmac_sha256(/*tls,*/ a, SECRET, SEED, NULL);
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//TODO: convert hmac to precomputed
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for(;;) {
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@ -466,16 +523,16 @@ static void prf_hmac(tls_state_t *tls,
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if (outbuf_size <= MAC_size) {
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/* Last, possibly incomplete, block */
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/* (use a[] as temp buffer) */
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hmac(tls, a, SECRET, A, SEED, NULL);
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hmac_sha256(/*tls,*/ a, SECRET, A, SEED, NULL);
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memcpy(out_p, a, outbuf_size);
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return;
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}
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/* Not last block. Store directly to result buffer */
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hmac(tls, out_p, SECRET, A, SEED, NULL);
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hmac_sha256(/*tls,*/ out_p, SECRET, A, SEED, NULL);
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out_p += MAC_size;
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outbuf_size -= MAC_size;
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/* A(2) = HMAC_hash(secret, A(1)) */
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hmac(tls, a, SECRET, A, NULL);
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hmac_sha256(/*tls,*/ a, SECRET, A, NULL);
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}
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#undef A
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#undef SECRET
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@ -823,9 +880,10 @@ static int tls_xread_record(tls_state_t *tls)
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int padding_len;
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if (sz & (AES_BLOCKSIZE-1)
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|| sz < tls->min_encrypted_len_on_read
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|| sz < (int)tls->min_encrypted_len_on_read
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) {
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bb_error_msg_and_die("bad encrypted len:%u", sz);
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bb_error_msg_and_die("bad encrypted len:%u < %u",
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sz, tls->min_encrypted_len_on_read);
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}
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/* Decrypt content+MAC+padding, moving it over IV in the process */
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psAesInit(&ctx, p, /* IV */
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@ -1301,13 +1359,17 @@ static void get_server_hello(tls_state_t *tls)
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if (cipher == TLS_RSA_WITH_AES_128_CBC_SHA) {
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tls->key_size = AES128_KEYSIZE;
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tls->MAC_size = SHA1_OUTSIZE;
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sha1_begin(&tls->hsd->handshake_hash_ctx);
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}
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else { /* TLS_RSA_WITH_AES_256_CBC_SHA256 */
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tls->key_size = AES256_KEYSIZE;
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tls->MAC_size = SHA256_OUTSIZE;
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sha256_begin(&tls->hsd->handshake_hash_ctx);
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}
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/* Handshake hash eventually destined to FINISHED record
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* is sha256 regardless of cipher
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* (at least for all ciphers defined by RFC5246).
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* It's not sha1 for AES_128_CBC_SHA - only MAC is sha1, not this hash.
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*/
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sha256_begin(&tls->hsd->handshake_hash_ctx);
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hash_handshake(tls, ">> client hello hash:%s",
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tls->hsd->saved_client_hello, tls->hsd->saved_client_hello_size
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);
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@ -1389,6 +1451,7 @@ static void send_client_key_exchange(tls_state_t *tls)
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// version negotiated for the connection."
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rsa_premaster[0] = TLS_MAJ;
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rsa_premaster[1] = TLS_MIN;
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dump_hex("premaster:%s\n", rsa_premaster, sizeof(rsa_premaster));
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len = psRsaEncryptPub(/*pool:*/ NULL,
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/* psRsaKey_t* */ &tls->hsd->server_rsa_pub_key,
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rsa_premaster, /*inlen:*/ sizeof(rsa_premaster),
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@ -1417,7 +1480,7 @@ static void send_client_key_exchange(tls_state_t *tls)
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// [0..47];
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// The master secret is always exactly 48 bytes in length. The length
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// of the premaster secret will vary depending on key exchange method.
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prf_hmac(tls,
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prf_hmac_sha256(/*tls,*/
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tls->hsd->master_secret, sizeof(tls->hsd->master_secret),
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rsa_premaster, sizeof(rsa_premaster),
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"master secret",
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@ -1465,7 +1528,7 @@ static void send_client_key_exchange(tls_state_t *tls)
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memcpy(&tmp64[0] , &tls->hsd->client_and_server_rand32[32], 32);
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memcpy(&tmp64[32], &tls->hsd->client_and_server_rand32[0] , 32);
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prf_hmac(tls,
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prf_hmac_sha256(/*tls,*/
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tls->client_write_MAC_key, 2 * (tls->MAC_size + tls->key_size),
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// also fills:
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// server_write_MAC_key[]
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@ -1548,7 +1611,7 @@ static void send_client_finished(tls_state_t *tls)
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fill_handshake_record_hdr(record, HANDSHAKE_FINISHED, sizeof(*record));
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len = get_handshake_hash(tls, handshake_hash);
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prf_hmac(tls,
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prf_hmac_sha256(/*tls,*/
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record->prf_result, sizeof(record->prf_result),
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tls->hsd->master_secret, sizeof(tls->hsd->master_secret),
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"client finished",
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@ -1645,9 +1708,14 @@ void FAST_FUNC tls_handshake(tls_state_t *tls, const char *sni)
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dbg("<< CHANGE_CIPHER_SPEC\n");
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if (tls->cipher_id == TLS_RSA_WITH_NULL_SHA256)
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tls->min_encrypted_len_on_read = tls->MAC_size;
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else
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/* all incoming packets now should be encrypted and have IV + MAC + padding */
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tls->min_encrypted_len_on_read = AES_BLOCKSIZE + tls->MAC_size + AES_BLOCKSIZE;
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else {
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unsigned mac_blocks = (unsigned)(tls->MAC_size + AES_BLOCKSIZE-1) / AES_BLOCKSIZE;
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/* all incoming packets now should be encrypted and have
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* at least IV + (MAC padded to blocksize):
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*/
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tls->min_encrypted_len_on_read = AES_BLOCKSIZE + (mac_blocks * AES_BLOCKSIZE);
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dbg("min_encrypted_len_on_read: %u", tls->min_encrypted_len_on_read);
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}
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/* Get (encrypted) FINISHED from the server */
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len = tls_xread_record(tls);
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