commit e3124fef54f90828f7b06c41fd4e39ef7778f2e3 Author: teor <teor@torproject.org> Date: Fri Apr 5 15:06:30 2019 +1000 crypto_format: Remove the return value from curve25519_public_to_base64() And fix the documentation on the function: it does produce trailing "="s as padding. Also remove all checks for the return value, which were redundant anyway, because the function never failed. Part of 29660. --- src/feature/hs/hs_descriptor.c | 21 ++++++--------------- src/lib/crypt_ops/crypto_curve25519.h | 4 ++-- src/lib/crypt_ops/crypto_format.c | 23 +++++++++++++++-------- src/test/test_crypto.c | 2 +- 4 files changed, 24 insertions(+), 26 deletions(-) diff --git a/src/feature/hs/hs_descriptor.c b/src/feature/hs/hs_descriptor.c index 8f7bdf86e..279359702 100644 --- a/src/feature/hs/hs_descriptor.c +++ b/src/feature/hs/hs_descriptor.c @@ -403,9 +403,7 @@ encode_enc_key(const hs_desc_intro_point_t *ip) tor_assert(ip); /* Base64 encode the encryption key for the "enc-key" field. */ - if (curve25519_public_to_base64(key_b64, &ip->enc_key) < 0) { - goto done; - } + curve25519_public_to_base64(key_b64, &ip->enc_key); if (tor_cert_encode_ed22519(ip->enc_key_cert, &encoded_cert) < 0) { goto done; } @@ -421,7 +419,7 @@ encode_enc_key(const hs_desc_intro_point_t *ip) } /* Encode an introduction point onion key. Return a newly allocated string - * with it. On failure, return NULL. */ + * with it. Can not fail. */ static char * encode_onion_key(const hs_desc_intro_point_t *ip) { @@ -431,12 +429,9 @@ encode_onion_key(const hs_desc_intro_point_t *ip) tor_assert(ip); /* Base64 encode the encryption key for the "onion-key" field. */ - if (curve25519_public_to_base64(key_b64, &ip->onion_key) < 0) { - goto done; - } + curve25519_public_to_base64(key_b64, &ip->onion_key); tor_asprintf(&encoded, "%s ntor %s", str_ip_onion_key, key_b64); - done: return encoded; } @@ -797,8 +792,8 @@ get_inner_encrypted_layer_plaintext(const hs_descriptor_t *desc) /* Create the middle layer of the descriptor, which includes the client auth * data and the encrypted inner layer (provided as a base64 string at * <b>layer2_b64_ciphertext</b>). Return a newly-allocated string with the - * layer plaintext, or NULL if an error occurred. It's the responsibility of - * the caller to free the returned string. */ + * layer plaintext. It's the responsibility of the caller to free the returned + * string. Can not fail. */ static char * get_outer_encrypted_layer_plaintext(const hs_descriptor_t *desc, const char *layer2_b64_ciphertext) @@ -817,10 +812,7 @@ get_outer_encrypted_layer_plaintext(const hs_descriptor_t *desc, tor_assert(!tor_mem_is_zero((char *) ephemeral_pubkey->public_key, CURVE25519_PUBKEY_LEN)); - if (curve25519_public_to_base64(ephemeral_key_base64, - ephemeral_pubkey) < 0) { - goto done; - } + curve25519_public_to_base64(ephemeral_key_base64, ephemeral_pubkey); smartlist_add_asprintf(lines, "%s %s\n", str_desc_auth_key, ephemeral_key_base64); @@ -845,7 +837,6 @@ get_outer_encrypted_layer_plaintext(const hs_descriptor_t *desc, layer1_str = smartlist_join_strings(lines, "", 0, NULL); - done: /* We need to memwipe all lines because it contains the ephemeral key */ SMARTLIST_FOREACH(lines, char *, a, memwipe(a, 0, strlen(a))); SMARTLIST_FOREACH(lines, char *, a, tor_free(a)); diff --git a/src/lib/crypt_ops/crypto_curve25519.h b/src/lib/crypt_ops/crypto_curve25519.h index 061a7a350..cd23169cd 100644 --- a/src/lib/crypt_ops/crypto_curve25519.h +++ b/src/lib/crypt_ops/crypto_curve25519.h @@ -76,8 +76,8 @@ STATIC int curve25519_basepoint_impl(uint8_t *output, const uint8_t *secret); int curve25519_public_from_base64(curve25519_public_key_t *pkey, const char *input); -int curve25519_public_to_base64(char *output, - const curve25519_public_key_t *pkey); +void curve25519_public_to_base64(char *output, + const curve25519_public_key_t *pkey); void curve25519_set_impl_params(int use_ed); void curve25519_init(void); diff --git a/src/lib/crypt_ops/crypto_format.c b/src/lib/crypt_ops/crypto_format.c index 217ac8959..800f4ad5b 100644 --- a/src/lib/crypt_ops/crypto_format.c +++ b/src/lib/crypt_ops/crypto_format.c @@ -131,20 +131,27 @@ crypto_read_tagged_contents_from_file(const char *fname, return r; } -/** Encode <b>pkey</b> as a base64-encoded string, without trailing "=" +/** Encode <b>pkey</b> as a base64-encoded string, including trailing "=" * characters, in the buffer <b>output</b>, which must have at least - * CURVE25519_BASE64_PADDED_LEN+1 bytes available. Return 0 on success, -1 on - * failure. */ -int + * CURVE25519_BASE64_PADDED_LEN+1 bytes available. + * Can not fail. + * + * Careful! CURVE25519_BASE64_PADDED_LEN is one byte longer than + * ED25519_BASE64_LEN. + */ +void curve25519_public_to_base64(char *output, const curve25519_public_key_t *pkey) { char buf[128]; - base64_encode(buf, sizeof(buf), - (const char*)pkey->public_key, CURVE25519_PUBKEY_LEN, 0); - buf[CURVE25519_BASE64_PADDED_LEN] = '\0'; + int n = base64_encode(buf, sizeof(buf), + (const char*)pkey->public_key, + CURVE25519_PUBKEY_LEN, 0); + /* These asserts should always succeed, unless there is a bug in + * base64_encode(). */ + tor_assert(n == CURVE25519_BASE64_PADDED_LEN); + tor_assert(buf[CURVE25519_BASE64_PADDED_LEN] == '\0'); memcpy(output, buf, CURVE25519_BASE64_PADDED_LEN+1); - return 0; } /** Try to decode a base64-encoded curve25519 public key from <b>input</b> diff --git a/src/test/test_crypto.c b/src/test/test_crypto.c index fb8046fd2..5f53ba688 100644 --- a/src/test/test_crypto.c +++ b/src/test/test_crypto.c @@ -2075,7 +2075,7 @@ test_crypto_curve25519_encode(void *arg) curve25519_secret_key_generate(&seckey, 0); curve25519_public_key_generate(&key1, &seckey); - tt_int_op(0, OP_EQ, curve25519_public_to_base64(buf, &key1)); + curve25519_public_to_base64(buf, &key1); tt_int_op(CURVE25519_BASE64_PADDED_LEN, OP_EQ, strlen(buf)); tt_int_op(0, OP_EQ, curve25519_public_from_base64(&key2, buf));