commit 94b34d1be6f20c967736ba858d6e765fd369c4e8 Author: Nick Mathewson nickm@torproject.org Date: Tue May 3 17:08:56 2016 -0400

At long last, unit tests for degenerate DH public keys.

Apparently, we detect and reject them correctly. Aren't you glad? --- src/test/test_crypto.c | 68 +++++++++++++++++++++++++++++++++++++++++++++++--- 1 file changed, 65 insertions(+), 3 deletions(-)

diff --git a/src/test/test_crypto.c b/src/test/test_crypto.c index e89b94e..dd9a376 100644 --- a/src/test/test_crypto.c +++ b/src/test/test_crypto.c @@ -65,9 +65,71 @@ test_crypto_dh(void *arg) tt_mem_op(s1,OP_EQ, s2, s1len);

{ - /* XXXX Now fabricate some bad values and make sure they get caught, - * Check 0, 1, N-1, >= N, etc. - */ + /* Now fabricate some bad values and make sure they get caught. */ + + /* 1 and 0 should both fail. */ + s1len = crypto_dh_compute_secret(LOG_WARN, dh1, "\x01", 1, s1, 50); + tt_int_op(-1, OP_EQ, s1len); + + s1len = crypto_dh_compute_secret(LOG_WARN, dh1, "\x00", 1, s1, 50); + tt_int_op(-1, OP_EQ, s1len); + + memset(p1, 0, DH_BYTES); /* 0 with padding. */ + s1len = crypto_dh_compute_secret(LOG_WARN, dh1, p1, DH_BYTES, s1, 50); + tt_int_op(-1, OP_EQ, s1len); + + p1[DH_BYTES-1] = 1; /* 1 with padding*/ + s1len = crypto_dh_compute_secret(LOG_WARN, dh1, p1, DH_BYTES, s1, 50); + tt_int_op(-1, OP_EQ, s1len); + + /* 2 is okay, though weird. */ + s1len = crypto_dh_compute_secret(LOG_WARN, dh1, "\x02", 1, s1, 50); + tt_int_op(50, OP_EQ, s1len); + + const char P[] = + "FFFFFFFFFFFFFFFFC90FDAA22168C234C4C6628B80DC1CD129024E08" + "8A67CC74020BBEA63B139B22514A08798E3404DDEF9519B3CD3A431B" + "302B0A6DF25F14374FE1356D6D51C245E485B576625E7EC6F44C42E9" + "A637ED6B0BFF5CB6F406B7EDEE386BFB5A899FA5AE9F24117C4B1FE6" + "49286651ECE65381FFFFFFFFFFFFFFFF"; + + /* p-1, p, and so on are not okay. */ + base16_decode(p1, sizeof(p1), P, strlen(P)); + + s1len = crypto_dh_compute_secret(LOG_WARN, dh1, p1, DH_BYTES, s1, 50); + tt_int_op(-1, OP_EQ, s1len); + + p1[DH_BYTES-1] = 0xFE; /* p-1 */ + s1len = crypto_dh_compute_secret(LOG_WARN, dh1, p1, DH_BYTES, s1, 50); + tt_int_op(-1, OP_EQ, s1len); + + p1[DH_BYTES-1] = 0xFD; /* p-2 works fine */ + s1len = crypto_dh_compute_secret(LOG_WARN, dh1, p1, DH_BYTES, s1, 50); + tt_int_op(50, OP_EQ, s1len); + + const char P_plus_one[] = + "FFFFFFFFFFFFFFFFC90FDAA22168C234C4C6628B80DC1CD129024E08" + "8A67CC74020BBEA63B139B22514A08798E3404DDEF9519B3CD3A431B" + "302B0A6DF25F14374FE1356D6D51C245E485B576625E7EC6F44C42E9" + "A637ED6B0BFF5CB6F406B7EDEE386BFB5A899FA5AE9F24117C4B1FE6" + "49286651ECE653820000000000000000"; + + base16_decode(p1, sizeof(p1), P_plus_one, strlen(P_plus_one)); + + s1len = crypto_dh_compute_secret(LOG_WARN, dh1, p1, DH_BYTES, s1, 50); + tt_int_op(-1, OP_EQ, s1len); + + p1[DH_BYTES-1] = 0x01; /* p+2 */ + s1len = crypto_dh_compute_secret(LOG_WARN, dh1, p1, DH_BYTES, s1, 50); + tt_int_op(-1, OP_EQ, s1len); + + p1[DH_BYTES-1] = 0xff; /* p+256 */ + s1len = crypto_dh_compute_secret(LOG_WARN, dh1, p1, DH_BYTES, s1, 50); + tt_int_op(-1, OP_EQ, s1len); + + memset(p1, 0xff, sizeof(DH_BYTES)), /* 2^1024-1 */ + s1len = crypto_dh_compute_secret(LOG_WARN, dh1, p1, DH_BYTES, s1, 50); + tt_int_op(-1, OP_EQ, s1len); }

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