package/libs/openssl/patches/140-allow-prefer-chacha20.patch

   1 From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
   2 From: Eneas U de Queiroz <cote2004-github@yahoo.com>
   3 Date: Thu, 27 Sep 2018 08:44:39 -0300
   4 Subject: Add OPENSSL_PREFER_CHACHA_OVER_GCM option
   5
   6 This enables a compile-time option to prefer ChaCha20-Poly1305 over
   7 AES-GCM in the openssl default ciphersuite, which is useful in systems
   8 without AES specific CPU instructions.
   9 OPENSSL_PREFER_CHACHA_OVER_GCM must be defined to enable it.
  10
  11 Note that this does not have the same effect as the
  12 SL_OP_PRIORITIZE_CHACHA option, which prioritizes ChaCha20-Poly1305 only
  13 when the client has it on top of its ciphersuite preference.
  14
  15 Signed-off-by: Eneas U de Queiroz <cote2004-github@yahoo.com>
  16
  17 --- a/ssl/ssl_ciph.c
  18 +++ b/ssl/ssl_ciph.c
  19 @@ -1505,11 +1505,29 @@ STACK_OF(SSL_CIPHER) *ssl_create_cipher_
  20      ssl_cipher_apply_rule(0, SSL_kECDHE, 0, 0, 0, 0, 0, CIPHER_DEL, -1, &head,
  21                            &tail);
  22
  23 +    /*
  24 +     * If OPENSSL_PREFER_CHACHA_OVER_GCM is defined, ChaCha20_Poly1305
  25 +     * will be placed before AES-256.  Otherwise, the default behavior of
  26 +     * preferring GCM over CHACHA is used.
  27 +     * This is useful for systems that do not have AES-specific CPU
  28 +     * instructions, where ChaCha20-Poly1305 is 3 times faster than AES.
  29 +     * Note that this does not have the same effect as the SSL_OP_PRIORITIZE_CHACHA
  30 +     * option, which prioritizes ChaCha20-Poly1305 only when the client has it on top
  31 +     * of its ciphersuite preference.
  32 +     */
  33 +
  34 +#ifdef OPENSSL_PREFER_CHACHA_OVER_GCM
  35 +    ssl_cipher_apply_rule(0, 0, 0, SSL_CHACHA20, 0, 0, 0, CIPHER_ADD, -1,
  36 +                          &head, &tail);
  37 +    ssl_cipher_apply_rule(0, 0, 0, SSL_AESGCM, 0, 0, 0, CIPHER_ADD, -1,
  38 +                          &head, &tail);
  39 +#else
  40      /* Within each strength group, we prefer GCM over CHACHA... */
  41      ssl_cipher_apply_rule(0, 0, 0, SSL_AESGCM, 0, 0, 0, CIPHER_ADD, -1,
  42                            &head, &tail);
  43      ssl_cipher_apply_rule(0, 0, 0, SSL_CHACHA20, 0, 0, 0, CIPHER_ADD, -1,
  44                            &head, &tail);
  45 +#endif
  46
  47      /*
  48       * ...and generally, our preferred cipher is AES.
  49 @@ -1564,7 +1582,7 @@ STACK_OF(SSL_CIPHER) *ssl_create_cipher_
  50       * Within each group, ciphers remain sorted by strength and previous
  51       * preference, i.e.,
  52       * 1) ECDHE > DHE
  53 -     * 2) GCM > CHACHA
  54 +     * 2) GCM > CHACHA, reversed if OPENSSL_PREFER_CHACHA_OVER_GCM is defined
  55       * 3) AES > rest
  56       * 4) TLS 1.2 > legacy
  57       *
  58 @@ -2235,7 +2253,13 @@ const char *OSSL_default_cipher_list(voi
  59   */
  60  const char *OSSL_default_ciphersuites(void)
  61  {
  62 +#ifdef OPENSSL_PREFER_CHACHA_OVER_GCM
  63 +    return "TLS_CHACHA20_POLY1305_SHA256:"
  64 +           "TLS_AES_256_GCM_SHA384:"
  65 +           "TLS_AES_128_GCM_SHA256";
  66 +#else
  67      return "TLS_AES_256_GCM_SHA384:"
  68             "TLS_CHACHA20_POLY1305_SHA256:"
  69             "TLS_AES_128_GCM_SHA256";
  70 +#endif
  71  }
  72 --- a/include/openssl/ssl.h.in
  73 +++ b/include/openssl/ssl.h.in
  74 @@ -195,9 +195,15 @@ extern "C" {
  75   * DEPRECATED IN 3.0.0, in favor of OSSL_default_ciphersuites()
  76   * Update both macro and function simultaneously
  77   */
  78 -#  define TLS_DEFAULT_CIPHERSUITES "TLS_AES_256_GCM_SHA384:" \
  79 -                                   "TLS_CHACHA20_POLY1305_SHA256:" \
  80 -                                   "TLS_AES_128_GCM_SHA256"
  81 +#  ifdef OPENSSL_PREFER_CHACHA_OVER_GCM
  82 +#   define TLS_DEFAULT_CIPHERSUITES "TLS_CHACHA20_POLY1305_SHA256:" \
  83 +                                    "TLS_AES_256_GCM_SHA384:" \
  84 +                                    "TLS_AES_128_GCM_SHA256"
  85 +#  else
  86 +#   define TLS_DEFAULT_CIPHERSUITES "TLS_AES_256_GCM_SHA384:" \
  87 +                                    "TLS_CHACHA20_POLY1305_SHA256:" \
  88 +                                    "TLS_AES_128_GCM_SHA256"
  89 +#  endif
  90  # endif
  91  /*
  92   * As of OpenSSL 1.0.0, ssl_create_cipher_list() in ssl/ssl_ciph.c always