commit 01733e2b1568dacea26765800fab2c66f0b16bd1 Author: Nick Mathewson nickm@torproject.org Date: Wed Sep 23 11:22:26 2015 -0400
New AuthDirPinKeys option to enable/disable keypinning enforcement
Implements ticket #17135. We're going to need this one to avoid chaos as everybody figures out how ed25519 keys work. --- src/or/dirserv.c | 27 +++++++++++++++++---------- src/or/keypin.c | 44 ++++++++++++++++++++++++++++++-------------- src/or/keypin.h | 3 ++- src/test/test_keypin.c | 3 ++- 4 files changed, 51 insertions(+), 26 deletions(-)
diff --git a/src/or/dirserv.c b/src/or/dirserv.c index 53b450c..8d9f166 100644 --- a/src/or/dirserv.c +++ b/src/or/dirserv.c @@ -248,6 +248,7 @@ dirserv_router_get_status(const routerinfo_t *router, const char **msg, int severity) { char d[DIGEST_LEN]; + const int key_pinning = get_options()->AuthDirPinKeys;
if (crypto_pk_get_digest(router->identity_pkey, d)) { log_warn(LD_BUG,"Error computing fingerprint"); @@ -261,14 +262,16 @@ dirserv_router_get_status(const routerinfo_t *router, const char **msg, if (KEYPIN_MISMATCH == keypin_check((const uint8_t*)router->cache_info.identity_digest, router->signing_key_cert->signing_key.pubkey)) { - if (msg) { - *msg = "Ed25519 identity key or RSA identity key has changed."; - } log_fn(severity, LD_DIR, "Descriptor from router %s has an Ed25519 key, " "but the <rsa,ed25519> keys don't match what they were before.", router_describe(router)); - return FP_REJECT; + if (key_pinning) { + if (msg) { + *msg = "Ed25519 identity key or RSA identity key has changed."; + } + return FP_REJECT; + } } } else { /* No ed25519 key */ @@ -277,13 +280,15 @@ dirserv_router_get_status(const routerinfo_t *router, const char **msg, log_fn(severity, LD_DIR, "Descriptor from router %s has no Ed25519 key, " "when we previously knew an Ed25519 for it. Ignoring for now, " - "since Tor 0.2.6 is under development.", + "since Ed25519 keys are fairly new.", router_describe(router)); #ifdef DISABLE_DISABLING_ED25519 - if (msg) { - *msg = "Ed25519 identity key has disappeared."; + if (key_pinning) { + if (msg) { + *msg = "Ed25519 identity key has disappeared."; + } + return FP_REJECT; } - return FP_REJECT; #endif } } @@ -582,6 +587,7 @@ dirserv_add_descriptor(routerinfo_t *ri, const char **msg, const char *source) char *desc, *nickname; const size_t desclen = ri->cache_info.signed_descriptor_len + ri->cache_info.annotations_len; + const int key_pinning = get_options()->AuthDirPinKeys; *msg = NULL;
/* If it's too big, refuse it now. Otherwise we'll cache it all over the @@ -626,7 +632,8 @@ dirserv_add_descriptor(routerinfo_t *ri, const char **msg, const char *source) if (ri->signing_key_cert) { keypin_status = keypin_check_and_add( (const uint8_t*)ri->cache_info.identity_digest, - ri->signing_key_cert->signing_key.pubkey); + ri->signing_key_cert->signing_key.pubkey, + ! key_pinning); } else { keypin_status = keypin_check_lone_rsa( (const uint8_t*)ri->cache_info.identity_digest); @@ -635,7 +642,7 @@ dirserv_add_descriptor(routerinfo_t *ri, const char **msg, const char *source) keypin_status = KEYPIN_NOT_FOUND; #endif } - if (keypin_status == KEYPIN_MISMATCH) { + if (keypin_status == KEYPIN_MISMATCH && key_pinning) { log_info(LD_DIRSERV, "Dropping descriptor from %s (source: %s) because " "its key did not match an older RSA/Ed25519 keypair", router_describe(ri), source); diff --git a/src/or/keypin.c b/src/or/keypin.c index 0c99429..047d2b0 100644 --- a/src/or/keypin.c +++ b/src/or/keypin.c @@ -48,7 +48,9 @@ static int keypin_journal_append_entry(const uint8_t *rsa_id_digest, const uint8_t *ed25519_id_key); static int keypin_check_and_add_impl(const uint8_t *rsa_id_digest, const uint8_t *ed25519_id_key, - int do_not_add); + const int do_not_add, + const int replace); +static int keypin_add_or_replace_entry_in_map(keypin_ent_t *ent);
static HT_HEAD(rsamap, keypin_ent_st) the_rsa_map = HT_INITIALIZER(); static HT_HEAD(edmap, keypin_ent_st) the_ed_map = HT_INITIALIZER(); @@ -100,12 +102,17 @@ HT_GENERATE2(edmap, keypin_ent_st, edmap_node, keypin_ent_hash_ed, * return KEYPIN_FOUND. If we find an entry that matches one key but * not the other, return KEYPIN_MISMATCH. If we have no entry for either * key, add such an entry to the table and return KEYPIN_ADDED. + * + * If <b>replace_existing_entry</b> is true, then any time we would have said + * KEYPIN_FOUND, we instead add this entry anyway and return KEYPIN_ADDED. */ int keypin_check_and_add(const uint8_t *rsa_id_digest, - const uint8_t *ed25519_id_key) + const uint8_t *ed25519_id_key, + const int replace_existing_entry) { - return keypin_check_and_add_impl(rsa_id_digest, ed25519_id_key, 0); + return keypin_check_and_add_impl(rsa_id_digest, ed25519_id_key, 0, + replace_existing_entry); }
/** @@ -116,7 +123,7 @@ int keypin_check(const uint8_t *rsa_id_digest, const uint8_t *ed25519_id_key) { - return keypin_check_and_add_impl(rsa_id_digest, ed25519_id_key, 1); + return keypin_check_and_add_impl(rsa_id_digest, ed25519_id_key, 1, 0); }
/** @@ -125,7 +132,8 @@ keypin_check(const uint8_t *rsa_id_digest, static int keypin_check_and_add_impl(const uint8_t *rsa_id_digest, const uint8_t *ed25519_id_key, - int do_not_add) + const int do_not_add, + const int replace) { keypin_ent_t search, *ent; memset(&search, 0, sizeof(search)); @@ -139,18 +147,21 @@ keypin_check_and_add_impl(const uint8_t *rsa_id_digest, if (tor_memeq(ent->ed25519_key, ed25519_id_key,sizeof(ent->ed25519_key))) { return KEYPIN_FOUND; /* Match on both keys. Great. */ } else { - return KEYPIN_MISMATCH; /* Found RSA with different Ed key */ + if (!replace) + return KEYPIN_MISMATCH; /* Found RSA with different Ed key */ } }
/* See if we know a different RSA key for this ed key */ - ent = HT_FIND(edmap, &the_ed_map, &search); - if (ent) { - /* If we got here, then the ed key matches and the RSA doesn't */ - tor_assert(fast_memeq(ent->ed25519_key, ed25519_id_key, - sizeof(ent->ed25519_key))); - tor_assert(fast_memneq(ent->rsa_id, rsa_id_digest, sizeof(ent->rsa_id))); - return KEYPIN_MISMATCH; + if (! replace) { + ent = HT_FIND(edmap, &the_ed_map, &search); + if (ent) { + /* If we got here, then the ed key matches and the RSA doesn't */ + tor_assert(fast_memeq(ent->ed25519_key, ed25519_id_key, + sizeof(ent->ed25519_key))); + tor_assert(fast_memneq(ent->rsa_id, rsa_id_digest, sizeof(ent->rsa_id))); + return KEYPIN_MISMATCH; + } }
/* Okay, this one is new to us. */ @@ -158,7 +169,12 @@ keypin_check_and_add_impl(const uint8_t *rsa_id_digest, return KEYPIN_NOT_FOUND;
ent = tor_memdup(&search, sizeof(search)); - keypin_add_entry_to_map(ent); + int r = keypin_add_or_replace_entry_in_map(ent); + if (! replace) { + tor_assert(r == 1); + } else { + tor_assert(r != 0); + } keypin_journal_append_entry(rsa_id_digest, ed25519_id_key); return KEYPIN_ADDED; } diff --git a/src/or/keypin.h b/src/or/keypin.h index 2a5b3f1..798ac1f 100644 --- a/src/or/keypin.h +++ b/src/or/keypin.h @@ -7,7 +7,8 @@ #include "testsupport.h"
int keypin_check_and_add(const uint8_t *rsa_id_digest, - const uint8_t *ed25519_id_key); + const uint8_t *ed25519_id_key, + const int replace_existing_entry); int keypin_check(const uint8_t *rsa_id_digest, const uint8_t *ed25519_id_key);
diff --git a/src/test/test_keypin.c b/src/test/test_keypin.c index 033578c..bd0f6fd 100644 --- a/src/test/test_keypin.c +++ b/src/test/test_keypin.c @@ -131,7 +131,8 @@ test_keypin_parse_file(void *arg) smartlist_free(mock_addent_got); }
-#define ADD(a,b) keypin_check_and_add((const uint8_t*)(a),(const uint8_t*)(b)) +#define ADD(a,b) keypin_check_and_add((const uint8_t*)(a),\ + (const uint8_t*)(b),0) #define LONE_RSA(a) keypin_check_lone_rsa((const uint8_t*)(a))
static void