Commit 72c1e5ac authored Sep 19, 2013 by Nick Mathewson

Switch ECDHE group default logic for bridge/relay TLS

According to the manpage, bridges use P256 for conformity and relays
use P224 for speed. But skruffy points out that we've gotten it
backwards in the code.

In this patch, we make the default P256 for everybody.

Fixes bug 9780; bugfix on 0.2.4.8-alpha.

parent fa1034cd

changes/bug9780

0 → 100644

+8 −0

Original line number	Diff line number	Diff line
		o Minor bugfixes (performance, fingerprinting):
		- Our default TLS ecdhe groups were backwards: we meant to be using
		P224 for relays (for performance win) and P256 for bridges (since
		it is more common in the wild). Instead we had it backwards. After
		reconsideration, we decided that the default should be P256 on all
		hosts, since its security is probably better, and since P224 is
		reportedly used quite little in the wild. Found by "skruffy" on
		IRC. Fix for bug 9780; bugfix on 0.2.4.8-alpha.

doc/tor.1.txt

+1 −1

Original line number	Diff line number	Diff line
		@@ -1642,7 +1642,7 @@ is non-zero):
		What EC group should we try to use for incoming TLS connections?
		P224 is faster, but makes us stand out more. Has no effect if
		we're a client, or if our OpenSSL version lacks support for ECDHE.
		(Default: P224 for public servers; P256 for bridges.)
		(Default: P256)

		[[CellStatistics]] CellStatistics 0\|1::
		When this option is enabled, Tor writes statistics on the mean time that

src/common/tortls.c

+1 −3

Original line number	Diff line number	Diff line
		@@ -1369,10 +1369,8 @@ tor_tls_context_new(crypto_pk_t *identity, unsigned int key_lifetime,
		nid = NID_secp224r1;
		else if (flags & TOR_TLS_CTX_USE_ECDHE_P256)
		nid = NID_X9_62_prime256v1;
		else if (flags & TOR_TLS_CTX_IS_PUBLIC_SERVER)
		nid = NID_X9_62_prime256v1;
		else
		nid = NID_secp224r1;
		nid = NID_X9_62_prime256v1;
		/* Use P-256 for ECDHE. */
		ec_key = EC_KEY_new_by_curve_name(nid);
		if (ec_key != NULL) /XXXX Handle errors? /