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Decide whether to use SSL flags based on runtime OpenSSL version.

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We need to do this because Apple doesn't update its dev-tools headers
when it updates its libraries in a security patch.  On the bright
side, this might get us out of shipping a statically linked OpenSSL on
OSX.

May fix bug 1225.
This commit is contained in:
Nick Mathewson 2010-01-29 17:02:17 -05:00
parent f75f7322b9
commit 8d68e5c748
2 changed files with 52 additions and 15 deletions
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6
ChangeLog
View File

@ -1,4 +1,10 @@
Changes in version 0.2.2.9-alpha - 2010-??-??
o Minor bugfixes:
- When deciding whether to use strange flags to turn TLS renegotiation
on, detect the OpenSSL version at run-time, not compile time. We
need to do this because Apple doesn't update its dev-tools headers
when it updates its libraries in a security patch.
o Code simplifications and refactoring:
- Generate our manpage and HTML documentation using Asciidoc. This
should make it easier to maintain the documentation, and produce

61
src/common/tortls.c
View File

@ -53,6 +53,24 @@
#define ADDR(tls) (((tls) && (tls)->address) ? tls->address : "peer")
/* We redefine these so that we can run correctly even if the vendor gives us
* a version of OpenSSL that does not match its header files. (Apple: I am
* looking at you.)
*/
#ifndef SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION
#define SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION 0x00040000L
#endif
#ifndef SSL3_FLAGS_ALLOW_UNSAFE_LEGACY_RENEGOTIATION
#define SSL3_FLAGS_ALLOW_UNSAFE_LEGACY_RENEGOTIATION 0x0010
#endif
/** Does the run-time openssl version look like we need
* SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION? */
static int use_unsafe_renegotiation_op = 0;
/** Does the run-time openssl version look like we need
* SSL3_FLAGS_ALLOW_UNSAFE_LEGACY_RENEGOTIATION? */
static int use_unsafe_renegotiation_flag = 0;
/** Structure holding the TLS state for a single connection. */
typedef struct tor_tls_context_t {
int refcnt;
@ -333,8 +351,28 @@ static void
tor_tls_init(void)
{
if (!tls_library_is_initialized) {
long version;
SSL_library_init();
SSL_load_error_strings();
version = SSLeay();
if (version >= 0x009070c0L && version < 0x00908000L) {
log_notice(LD_GENERAL, "OpenSSL %s looks like version 0.9.7l or later; "
"I will use SSL3_FLAGS to enable renegotation",
SSLeay_version(SSLEAY_VERSION));
use_unsafe_renegotiation_flag = 1;
use_unsafe_renegotiation_op = 1;
} else if (version >= 0x009080d0L) {
log_notice(LD_GENERAL, "OpenSSL %s looks like version 0.9.8m or later; "
"I will use SSL_OP to enable renegotiation",
SSLeay_version(SSLEAY_VERSION));
use_unsafe_renegotiation_flag = 1;
use_unsafe_renegotiation_op = 1;
} else {
log_info(LD_GENERAL, "OpenSSL %s has version %lx",
SSLeay_version(SSLEAY_VERSION), version);
}
tls_library_is_initialized = 1;
}
}
@ -591,7 +629,6 @@ tor_tls_context_new(crypto_pk_env_t *identity, unsigned int key_lifetime)
SSL_CTX_set_options(result->ctx,
SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION);
#endif
#ifdef SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION
/* Yes, we know what we are doing here. No, we do not treat a renegotiation
* as authenticating any earlier-received data.
*
@ -600,9 +637,10 @@ tor_tls_context_new(crypto_pk_env_t *identity, unsigned int key_lifetime)
* seems) broke anything that used SSL3_FLAGS_* for the purpose. So we need
* to do both.)
*/
SSL_CTX_set_options(result->ctx,
SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION);
#endif
if (use_unsafe_renegotiation_op) {
SSL_CTX_set_options(result->ctx,
SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION);
}
/* Don't actually allow compression; it uses ram and time, but the data
* we transmit is all encrypted anyway. */
if (result->ctx->comp_methods)
@ -943,19 +981,16 @@ tor_tls_set_renegotiate_callback(tor_tls_t *tls,
}
/** If this version of openssl requires it, turn on renegotiation on
* <b>tls</b>. (Our protocol never requires this for security, but it's nice
* to use belt-and-suspenders here.)
* <b>tls</b>.
*/
static void
tor_tls_unblock_renegotiation(tor_tls_t *tls)
{
#ifdef SSL3_FLAGS_ALLOW_UNSAFE_LEGACY_RENEGOTIATION
/* Yes, we know what we are doing here. No, we do not treat a renegotiation
* as authenticating any earlier-received data. */
tls->ssl->s3->flags |= SSL3_FLAGS_ALLOW_UNSAFE_LEGACY_RENEGOTIATION;
#else
(void)tls;
#endif
if (use_unsafe_renegotiation_flag) {
tls->ssl->s3->flags |= SSL3_FLAGS_ALLOW_UNSAFE_LEGACY_RENEGOTIATION;
}
}
/** If this version of openssl supports it, turn off renegotiation on
@ -965,11 +1000,7 @@ tor_tls_unblock_renegotiation(tor_tls_t *tls)
void
tor_tls_block_renegotiation(tor_tls_t *tls)
{
#ifdef SSL3_FLAGS_ALLOW_UNSAFE_LEGACY_RENEGOTIATION
tls->ssl->s3->flags &= ~SSL3_FLAGS_ALLOW_UNSAFE_LEGACY_RENEGOTIATION;
#else
(void)tls;
#endif
}
/** Return whether this tls initiated the connect (client) or