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 diff --git a/include/openssl/ssl.h b/include/openssl/ssl.h
  18 --- a/include/openssl/ssl.h
  19 +++ b/include/openssl/ssl.h
  20 @@ -173,9 +173,15 @@ extern "C" {
  21  # define SSL_DEFAULT_CIPHER_LIST "ALL:!COMPLEMENTOFDEFAULT:!eNULL"
  22  /* This is the default set of TLSv1.3 ciphersuites */
  23  # if !defined(OPENSSL_NO_CHACHA) && !defined(OPENSSL_NO_POLY1305)
  24 -#  define TLS_DEFAULT_CIPHERSUITES "TLS_AES_256_GCM_SHA384:" \
  25 -                                   "TLS_CHACHA20_POLY1305_SHA256:" \
  26 -                                   "TLS_AES_128_GCM_SHA256"
  27 +#  ifdef OPENSSL_PREFER_CHACHA_OVER_GCM
  28 +#   define TLS_DEFAULT_CIPHERSUITES "TLS_CHACHA20_POLY1305_SHA256:" \
  29 +                                    "TLS_AES_256_GCM_SHA384:" \
  30 +                                    "TLS_AES_128_GCM_SHA256"
  31 +#  else
  32 +#   define TLS_DEFAULT_CIPHERSUITES "TLS_AES_256_GCM_SHA384:" \
  33 +                                    "TLS_CHACHA20_POLY1305_SHA256:" \
  34 +                                    "TLS_AES_128_GCM_SHA256"
  35 +#  endif
  36  # else
  37  #  define TLS_DEFAULT_CIPHERSUITES "TLS_AES_256_GCM_SHA384:" \
  38                                     "TLS_AES_128_GCM_SHA256"
  39 diff --git a/ssl/ssl_ciph.c b/ssl/ssl_ciph.c
  40 --- a/ssl/ssl_ciph.c
  41 +++ b/ssl/ssl_ciph.c
  42 @@ -1467,11 +1467,29 @@ STACK_OF(SSL_CIPHER) *ssl_create_cipher_list(const SSL_METHOD *ssl_method,
  43      ssl_cipher_apply_rule(0, SSL_kECDHE, 0, 0, 0, 0, 0, CIPHER_DEL, -1, &head,
  44                            &tail);
  45
  46 +    /*
  47 +     * If OPENSSL_PREFER_CHACHA_OVER_GCM is defined, ChaCha20_Poly1305
  48 +     * will be placed before AES-256.  Otherwise, the default behavior of
  49 +     * preferring GCM over CHACHA is used.
  50 +     * This is useful for systems that do not have AES-specific CPU
  51 +     * instructions, where ChaCha20-Poly1305 is 3 times faster than AES.
  52 +     * Note that this does not have the same effect as the SSL_OP_PRIORITIZE_CHACHA
  53 +     * option, which prioritizes ChaCha20-Poly1305 only when the client has it on top
  54 +     * of its ciphersuite preference.
  55 +     */
  56 +
  57 +#ifdef OPENSSL_PREFER_CHACHA_OVER_GCM
  58 +    ssl_cipher_apply_rule(0, 0, 0, SSL_CHACHA20, 0, 0, 0, CIPHER_ADD, -1,
  59 +                          &head, &tail);
  60 +    ssl_cipher_apply_rule(0, 0, 0, SSL_AESGCM, 0, 0, 0, CIPHER_ADD, -1,
  61 +                          &head, &tail);
  62 +#else
  63      /* Within each strength group, we prefer GCM over CHACHA... */
  64      ssl_cipher_apply_rule(0, 0, 0, SSL_AESGCM, 0, 0, 0, CIPHER_ADD, -1,
  65                            &head, &tail);
  66      ssl_cipher_apply_rule(0, 0, 0, SSL_CHACHA20, 0, 0, 0, CIPHER_ADD, -1,
  67                            &head, &tail);
  68 +#endif
  69
  70      /*
  71       * ...and generally, our preferred cipher is AES.
  72 @@ -1527,7 +1545,7 @@ STACK_OF(SSL_CIPHER) *ssl_create_cipher_list(const SSL_METHOD *ssl_method,
  73       * Within each group, ciphers remain sorted by strength and previous
  74       * preference, i.e.,
  75       * 1) ECDHE > DHE
  76 -     * 2) GCM > CHACHA
  77 +     * 2) GCM > CHACHA, reversed if OPENSSL_PREFER_CHACHA_OVER_GCM is defined
  78       * 3) AES > rest
  79       * 4) TLS 1.2 > legacy
  80       *