commit fe1137be6f0fc01d7dfda568134590ecb5627eb4 Author: Robert Ransom rransom.8774@gmail.com Date: Thu Mar 3 15:34:53 2011 -0800

Use SSL_*_ex_data instead of SSL_*_app_data

SSL_*_app_data uses ex_data index 0, which will be the first one allocated by SSL_get_ex_new_index. Thus, if we ever started using the ex_data feature for some other purpose, or a library linked to Tor ever started using OpenSSL's ex_data feature, Tor would break in spectacular and mysterious ways. Using the SSL_*_ex_data functions directly now may save us from that particular form of breakage in the future.

But I would not be surprised if using OpenSSL's ex_data functions at all (directly or not) comes back to bite us on our backends quite hard. The specified behaviour of dup_func in the man page is stupid, and crypto/ex_data.c is a horrific mess. --- src/common/tortls.c | 21 +++++++++++++++++++-- 1 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/src/common/tortls.c b/src/common/tortls.c index 61cc4ba..905ecbb 100644 --- a/src/common/tortls.c +++ b/src/common/tortls.c @@ -151,12 +151,27 @@ static SSL_CIPHER *CLIENT_CIPHER_DUMMIES = NULL; static STACK_OF(SSL_CIPHER) *CLIENT_CIPHER_STACK = NULL; #endif

+/** The ex_data index in which we store a pointer to an SSL object's + * corresponding tor_tls_t object. */ +static int tor_tls_object_ex_data_index = -1; + +/** Helper: Allocate tor_tls_object_ex_data_index. */ +static void +tor_tls_allocate_tor_tls_object_ex_data_index() +{ + if (tor_tls_object_ex_data_index == -1) { + tor_tls_object_ex_data_index = + SSL_get_ex_new_index(0, NULL, NULL, NULL, NULL); + tor_assert(tor_tls_object_ex_data_index != -1); + } +} + /** Helper: given a SSL* pointer, return the tor_tls_t object using that * pointer. */ static INLINE tor_tls_t * tor_tls_get_by_ssl(const SSL *ssl) { - return SSL_get_app_data(ssl); + return SSL_get_ex_data(ssl, tor_tls_object_ex_data_index); }

static void tor_tls_context_decref(tor_tls_context_t *ctx); @@ -415,6 +430,8 @@ tor_tls_init(void) SSLeay_version(SSLEAY_VERSION), version); }

+ tor_tls_allocate_tor_tls_object_ex_data_index(); + tls_library_is_initialized = 1; } } @@ -1048,7 +1065,7 @@ tor_tls_new(int sock, int isServer) tor_free(result); return NULL; } - SSL_set_app_data(result->ssl, result); + SSL_set_ex_data(result->ssl, tor_tls_object_ex_data_index, result); SSL_set_bio(result->ssl, bio, bio); tor_tls_context_incref(context); result->context = context;