Small source fix makes using BoringSSL easier

[byllyfish]

I'm using BoringSSL with ASIO 1.11. BoringSSL is Google's downstream fork of OpenSSL that removes some of the cruft from OpenSSL while remaining source compatible. I've found three issues with ASIO, but I only really need one source fix (which is openssl-fork-agnostic):

diff --git a/asio/include/asio/ssl/detail/impl/openssl_init.ipp b/asio/include/asio/ssl/detail/impl/openssl_init.ipp
index 2c40d40..0229374 100644
--- a/asio/include/asio/ssl/detail/impl/openssl_init.ipp
+++ b/asio/include/asio/ssl/detail/impl/openssl_init.ipp
@@ -63,7 +63,11 @@ public:
     ::CRYPTO_set_id_callback(0);
     ::CRYPTO_set_locking_callback(0);
     ::ERR_free_strings();
+#if OPENSSL_VERSION_NUMBER >= 0x10000000L
+    ::ERR_remove_thread_state(NULL);
+#else
     ::ERR_remove_state(0);
+#endif // OPENSSL_VERSION_NUMBER >= 0x10000000L
     ::EVP_cleanup();
     ::CRYPTO_cleanup_all_ex_data();
     ::CONF_modules_unload(1);

ERR_remove_state was deprecated in favor of ERR_remove_thread_state in OpenSSL 1.0.0 (although it remained for binary compatibility).

https://www.openssl.org/docs/crypto/ERR_remove_state.html

The other two issues are:

1. CONF_modules_unload isn't declared or defined in BoringSSL. Config modules aren't supported.
2. SSL_R_SHORT_READ isn't defined in BoringSSL. Unused error codes have been removed.

These last two issues can be handled in my own code with a header prefix:

#if defined(OPENSSL_IS_BORINGSSL)
extern "C" {
#if !defined(SSL_R_SHORT_READ)
# define SSL_R_SHORT_READ    SSL_R_UNEXPECTED_RECORD
#endif // !defined(SSL_R_SHORT_READ)
inline void CONF_modules_unload(int p) {}
}
#endif // defined(OPENSSL_IS_BORINGSSL)

[thughes]

+1

FWIW, it looks like SSL_R_SHORT_READ has been removed in openssl as well: openssl/openssl@45f55f6

[chriskohlhoff]

Fixed in commits 628e3ca, 5fa8053 and 92bfc62.

Note that a new ssl::error::stream_truncated error code has been added, rather than reusing SSL_R_SHORT_READ.

[RajatKumar007]

I am trying to integrate boringssl with boost asio version 1.10.7. But getting several compilation error as :

boost/asio/ssl/impl/context.ipp:208:16: error: member access into incomplete type 'SSL_CTX' (aka 'ssl_ctx_st')
if (handle_->default_passwd_callback_userdata)
^
boringssl/include\openssl/base.h:333:16: note: forward declaration of 'ssl_ctx_st'
typedef struct ssl_ctx_st SSL_CTX;

boost/asio/ssl/detail/impl/engine.ipp:207:34: error: too many arguments provided to function-like macro invocation
ERR_PACK(ERR_LIB_SSL, 0, SSL_R_SHORT_READ),
^
boringssl/include\openssl/err.h:446:9: note: macro 'ERR_PACK' defined here
#define ERR_PACK(lib, reason)