tls: introduce FEATURE_TLS_SHA1 to make SHA1 code optional
When disabled: function old new delta xwrite_encrypted 580 579 -1 prf_hmac_sha256 222 217 -5 hmac_begin 158 149 -9 static.ciphers 32 20 -12 tls_handshake 2115 2095 -20 hmac 87 61 -26 ------------------------------------------------------------------------------ (add/remove: 0/0 grow/shrink: 0/6 up/down: 0/-73) Total: -73 bytes Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
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Denys Vlasenko
parent
dafbc2cdb8
commit
71fa5b0a4c
@ -46,6 +46,17 @@ config VERBOSE_RESOLUTION_ERRORS
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"can't resolve 'hostname.com'" and want to know more.
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This may increase size of your executable a bit.
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config FEATURE_TLS_SHA1
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bool "In TLS code, support ciphers which use deprecated SHA1"
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depends on TLS
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default n
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help
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Selecting this option increases interoperability with very old
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servers, but slightly increases code size.
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Most TLS servers support SHA256 today (2018), since SHA1 is
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considered possibly insecure (although not yet definitely broken).
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INSERT
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source networking/udhcp/Config.in
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@ -6,6 +6,8 @@
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//config:config TLS
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//config: bool #No description makes it a hidden option
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//config: default n
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//Note:
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//Config.src also defines FEATURE_TLS_SHA1 option
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//kbuild:lib-$(CONFIG_TLS) += tls.o
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//kbuild:lib-$(CONFIG_TLS) += tls_pstm.o
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@ -394,7 +396,7 @@ static void hash_handshake(tls_state_t *tls, const char *fmt, const void *buffer
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dump_hex(fmt, buffer, len);
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dbg(" (%u bytes) ", (int)len);
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len = sha_peek(&tls->hsd->handshake_hash_ctx, h);
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if (len == SHA1_OUTSIZE)
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if (ENABLE_FEATURE_TLS_SHA1 && len == SHA1_OUTSIZE)
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dump_hex("sha1:%s\n", h, len);
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else
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if (len == SHA256_OUTSIZE)
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@ -421,6 +423,11 @@ typedef struct hmac_precomputed {
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} hmac_precomputed_t;
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typedef void md5sha_begin_func(md5sha_ctx_t *ctx) FAST_FUNC;
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#if !ENABLE_FEATURE_TLS_SHA1
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#define hmac_begin(pre,key,key_size,begin) \
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hmac_begin(pre,key,key_size)
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#define begin sha256_begin
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#endif
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static void hmac_begin(hmac_precomputed_t *pre, uint8_t *key, unsigned key_size, md5sha_begin_func *begin)
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{
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uint8_t key_xor_ipad[SHA_INSIZE];
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@ -461,6 +468,7 @@ static void hmac_begin(hmac_precomputed_t *pre, uint8_t *key, unsigned key_size,
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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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#undef begin
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static unsigned hmac_sha_precomputed_v(
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hmac_precomputed_t *pre,
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@ -498,6 +506,10 @@ static unsigned hmac_sha_precomputed(hmac_precomputed_t *pre_init, uint8_t *out,
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return len;
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}
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#if !ENABLE_FEATURE_TLS_SHA1
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#define hmac(tls,out,key,key_size,...) \
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hmac(out,key,key_size, __VA_ARGS__)
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#endif
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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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@ -507,7 +519,7 @@ static unsigned hmac(tls_state_t *tls, uint8_t *out, uint8_t *key, unsigned key_
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va_start(va, key_size);
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hmac_begin(&pre, key, key_size,
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(tls->MAC_size == SHA256_OUTSIZE)
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(ENABLE_FEATURE_TLS_SHA1 || tls->MAC_size == SHA256_OUTSIZE)
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? sha256_begin
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: sha1_begin
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);
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@ -1466,15 +1478,17 @@ static ALWAYS_INLINE void fill_handshake_record_hdr(void *buf, unsigned type, un
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static void send_client_hello_and_alloc_hsd(tls_state_t *tls, const char *sni)
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{
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#define NUM_CIPHERS (13 + ALLOW_RSA_NULL_SHA256)
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#define NUM_CIPHERS (7 + 6 * ENABLE_FEATURE_TLS_SHA1 + ALLOW_RSA_NULL_SHA256)
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static const uint8_t ciphers[] = {
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0x00,(1 + NUM_CIPHERS) * 2, //len16_be
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0x00,0xFF, //not a cipher - TLS_EMPTY_RENEGOTIATION_INFO_SCSV
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/* ^^^^^^ RFC 5746 Renegotiation Indication Extension - some servers will refuse to work with us otherwise */
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#if ENABLE_FEATURE_TLS_SHA1
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0xC0,0x09, // 1 TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA - ok: wget https://is.gd/
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0xC0,0x0A, // 2 TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA - ok: wget https://is.gd/
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0xC0,0x13, // 3 TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA - ok: openssl s_server ... -cipher ECDHE-RSA-AES128-SHA
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0xC0,0x14, // 4 TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA - ok: openssl s_server ... -cipher ECDHE-RSA-AES256-SHA (might fail with older openssl)
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#endif
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0xC0,0x23, // 5 TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256 - ok: wget https://is.gd/
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// 0xC0,0x24, // TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA384 - can't do SHA384 yet
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0xC0,0x27, // 6 TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256 - ok: openssl s_server ... -cipher ECDHE-RSA-AES128-SHA256
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@ -1485,12 +1499,16 @@ static void send_client_hello_and_alloc_hsd(tls_state_t *tls, const char *sni)
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0xC0,0x2F, // 8 TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 - ok: openssl s_server ... -cipher ECDHE-RSA-AES128-GCM-SHA256
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// 0xC0,0x30, // TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 - openssl s_server ... -cipher ECDHE-RSA-AES256-GCM-SHA384: "decryption failed or bad record mac"
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//possibly these too:
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#if ENABLE_FEATURE_TLS_SHA1
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// 0xC0,0x35, // TLS_ECDHE_PSK_WITH_AES_128_CBC_SHA
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// 0xC0,0x36, // TLS_ECDHE_PSK_WITH_AES_256_CBC_SHA
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#endif
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// 0xC0,0x37, // TLS_ECDHE_PSK_WITH_AES_128_CBC_SHA256
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// 0xC0,0x38, // TLS_ECDHE_PSK_WITH_AES_256_CBC_SHA384 - can't do SHA384 yet
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#if ENABLE_FEATURE_TLS_SHA1
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0x00,0x2F, // 9 TLS_RSA_WITH_AES_128_CBC_SHA - ok: openssl s_server ... -cipher AES128-SHA
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0x00,0x35, //10 TLS_RSA_WITH_AES_256_CBC_SHA - ok: openssl s_server ... -cipher AES256-SHA
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#endif
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0x00,0x3C, //11 TLS_RSA_WITH_AES_128_CBC_SHA256 - ok: openssl s_server ... -cipher AES128-SHA256
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0x00,0x3D, //12 TLS_RSA_WITH_AES_256_CBC_SHA256 - ok: openssl s_server ... -cipher AES256-SHA256
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0x00,0x9C, //13 TLS_RSA_WITH_AES_128_GCM_SHA256 - ok: openssl s_server ... -cipher AES128-GCM-SHA256
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@ -1669,10 +1687,12 @@ static void get_server_hello(tls_state_t *tls)
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/* Set up encryption params based on selected cipher */
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#if 0
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#if ENABLE_FEATURE_TLS_SHA1
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0xC0,0x09, // 1 TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA - ok: wget https://is.gd/
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0xC0,0x0A, // 2 TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA - ok: wget https://is.gd/
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0xC0,0x13, // 3 TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA - ok: openssl s_server ... -cipher ECDHE-RSA-AES128-SHA
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0xC0,0x14, // 4 TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA - ok: openssl s_server ... -cipher ECDHE-RSA-AES256-SHA (might fail with older openssl)
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#endif
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0xC0,0x23, // 5 TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256 - ok: wget https://is.gd/
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// 0xC0,0x24, // TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA384 - can't do SHA384 yet
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0xC0,0x27, // 6 TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256 - ok: openssl s_server ... -cipher ECDHE-RSA-AES128-SHA256
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@ -1682,12 +1702,16 @@ static void get_server_hello(tls_state_t *tls)
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0xC0,0x2F, // 8 TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 - ok: openssl s_server ... -cipher ECDHE-RSA-AES128-GCM-SHA256
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// 0xC0,0x30, // TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 - openssl s_server ... -cipher ECDHE-RSA-AES256-GCM-SHA384: "decryption failed or bad record mac"
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//possibly these too:
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#if ENABLE_FEATURE_TLS_SHA1
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// 0xC0,0x35, // TLS_ECDHE_PSK_WITH_AES_128_CBC_SHA
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// 0xC0,0x36, // TLS_ECDHE_PSK_WITH_AES_256_CBC_SHA
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#endif
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// 0xC0,0x37, // TLS_ECDHE_PSK_WITH_AES_128_CBC_SHA256
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// 0xC0,0x38, // TLS_ECDHE_PSK_WITH_AES_256_CBC_SHA384 - can't do SHA384 yet
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#if ENABLE_FEATURE_TLS_SHA1
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0x00,0x2F, // 9 TLS_RSA_WITH_AES_128_CBC_SHA - ok: openssl s_server ... -cipher AES128-SHA
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0x00,0x35, //10 TLS_RSA_WITH_AES_256_CBC_SHA - ok: openssl s_server ... -cipher AES256-SHA
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#endif
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0x00,0x3C, //11 TLS_RSA_WITH_AES_128_CBC_SHA256 - ok: openssl s_server ... -cipher AES128-SHA256
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0x00,0x3D, //12 TLS_RSA_WITH_AES_256_CBC_SHA256 - ok: openssl s_server ... -cipher AES256-SHA256
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0x00,0x9C, //13 TLS_RSA_WITH_AES_128_GCM_SHA256 - ok: openssl s_server ... -cipher AES128-GCM-SHA256
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@ -1706,7 +1730,7 @@ static void get_server_hello(tls_state_t *tls)
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/* Odd numbered C0xx use AES128 (even ones use AES256) */
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tls->key_size = AES128_KEYSIZE;
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}
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if (cipherid1 <= 0x14) {
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if (ENABLE_FEATURE_TLS_SHA1 && cipherid1 <= 0x14) {
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tls->MAC_size = SHA1_OUTSIZE;
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} else
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if (cipherid1 >= 0x2B && cipherid1 <= 0x30) {
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@ -1717,13 +1741,13 @@ static void get_server_hello(tls_state_t *tls)
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}
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} else {
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/* All 00xx are RSA */
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if (cipherid1 == 0x2F
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if ((ENABLE_FEATURE_TLS_SHA1 && cipherid1 == 0x2F)
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|| cipherid1 == 0x3C
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|| cipherid1 == 0x9C
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) {
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tls->key_size = AES128_KEYSIZE;
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}
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if (cipherid1 <= 0x35) {
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if (ENABLE_FEATURE_TLS_SHA1 && cipherid1 <= 0x35) {
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tls->MAC_size = SHA1_OUTSIZE;
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} else
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if (cipherid1 == 0x9C /*|| cipherid1 == 0x9D*/) {
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