commit 72c1e5acfe1c6f04f4d7d398fc4a964d4bc5b62e Author: Nick Mathewson nickm@torproject.org Date: Thu Sep 19 10:40:41 2013 -0400

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. --- changes/bug9780 | 8 ++++++++ doc/tor.1.txt | 2 +- src/common/tortls.c | 4 +--- 3 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/changes/bug9780 b/changes/bug9780 new file mode 100644 index 0000000..3cb51bd --- /dev/null +++ b/changes/bug9780 @@ -0,0 +1,8 @@ + 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. diff --git a/doc/tor.1.txt b/doc/tor.1.txt index b206275..38423c2 100644 --- a/doc/tor.1.txt +++ b/doc/tor.1.txt @@ -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 diff --git a/src/common/tortls.c b/src/common/tortls.c index b7e5bc1..72f6c40 100644 --- a/src/common/tortls.c +++ b/src/common/tortls.c @@ -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? */