Ejemplo n.º 1
0
void CompareLocalHash(ServerConnectionState *conn, char *sendbuffer, char *recvbuffer)
{
    unsigned char digest1[EVP_MAX_MD_SIZE + 1], digest2[EVP_MAX_MD_SIZE + 1];
    char filename[CF_BUFSIZE], rfilename[CF_BUFSIZE];
    char *sp;
    int i;

/* TODO - when safe change this proto string to sha2 */

    sscanf(recvbuffer, "MD5 %[^\n]", rfilename);

    sp = recvbuffer + strlen(recvbuffer) + CF_SMALL_OFFSET;

    for (i = 0; i < CF_DEFAULT_DIGEST_LEN; i++)
    {
        digest1[i] = *sp++;
    }

    memset(sendbuffer, 0, CF_BUFSIZE);

    TranslatePath(filename, rfilename);

    HashFile(filename, digest2, CF_DEFAULT_DIGEST);

    if ((HashesMatch(digest1, digest2, CF_DEFAULT_DIGEST)) || (HashesMatch(digest1, digest2, HASH_METHOD_MD5)))
    {
        sprintf(sendbuffer, "%s", CFD_FALSE);
        Log(LOG_LEVEL_DEBUG, "Hashes matched ok");
        SendTransaction(&conn->conn_info, sendbuffer, 0, CF_DONE);
    }
    else
    {
        sprintf(sendbuffer, "%s", CFD_TRUE);
        Log(LOG_LEVEL_DEBUG, "Hashes didn't match");
        SendTransaction(&conn->conn_info, sendbuffer, 0, CF_DONE);
    }
}
Ejemplo n.º 2
0
static int AuthenticationDialogue(ServerConnectionState *conn, char *recvbuffer, int recvlen)
{
    char in[CF_BUFSIZE], *out, *decrypted_nonce;
    BIGNUM *counter_challenge = NULL;
    unsigned char digest[EVP_MAX_MD_SIZE + 1] = { 0 };
    unsigned int crypt_len, nonce_len = 0, encrypted_len = 0;
    char sauth[10], iscrypt = 'n', enterprise_field = 'c';
    int len_n = 0, len_e = 0, keylen, session_size;
    unsigned long err;
    RSA *newkey;
    int digestLen = 0;
    HashMethod digestType;

    if ((PRIVKEY == NULL) || (PUBKEY == NULL))
    {
        Log(LOG_LEVEL_ERR, "No public/private key pair exists, create one with cf-key");
        return false;
    }

    if (FIPS_MODE)
    {
        digestType = CF_DEFAULT_DIGEST;
        digestLen = CF_DEFAULT_DIGEST_LEN;
    }
    else
    {
        digestType = HASH_METHOD_MD5;
        digestLen = CF_MD5_LEN;
    }

/* proposition C1 */
/* Opening string is a challenge from the client (some agent) */

    sauth[0] = '\0';

    sscanf(recvbuffer, "%s %c %u %u %c", sauth, &iscrypt, &crypt_len, &nonce_len, &enterprise_field);

    if ((crypt_len == 0) || (nonce_len == 0) || (strlen(sauth) == 0))
    {
        Log(LOG_LEVEL_INFO, "Protocol format error in authentation from IP %s", conn->hostname);
        return false;
    }

    if (nonce_len > CF_NONCELEN * 2)
    {
        Log(LOG_LEVEL_INFO, "Protocol deviant authentication nonce from %s", conn->hostname);
        return false;
    }

    if (crypt_len > 2 * CF_NONCELEN)
    {
        Log(LOG_LEVEL_INFO, "Protocol abuse in unlikely cipher from %s", conn->hostname);
        return false;
    }

/* Check there is no attempt to read past the end of the received input */

    if (recvbuffer + CF_RSA_PROTO_OFFSET + nonce_len > recvbuffer + recvlen)
    {
        Log(LOG_LEVEL_INFO, "Protocol consistency error in authentication from %s", conn->hostname);
        return false;
    }

    if ((strcmp(sauth, "SAUTH") != 0) || (nonce_len == 0) || (crypt_len == 0))
    {
        Log(LOG_LEVEL_INFO, "Protocol error in RSA authentication from IP '%s'", conn->hostname);
        return false;
    }

    Log(LOG_LEVEL_DEBUG, "Challenge encryption = %c, nonce = %d, buf = %d", iscrypt, nonce_len, crypt_len);


    decrypted_nonce = xmalloc(crypt_len);

    if (iscrypt == 'y')
    {
        if (RSA_private_decrypt
            (crypt_len, recvbuffer + CF_RSA_PROTO_OFFSET, decrypted_nonce, PRIVKEY, RSA_PKCS1_PADDING) <= 0)
        {
            err = ERR_get_error();

            Log(LOG_LEVEL_ERR,
                "Private decrypt failed = '%s'. Probably the client has the wrong public key for this server",
                ERR_reason_error_string(err));
            free(decrypted_nonce);
            return false;
        }
    }
    else
    {
        if (nonce_len > crypt_len)
        {
            Log(LOG_LEVEL_ERR, "Illegal challenge");
            free(decrypted_nonce);
            return false;
        }

        memcpy(decrypted_nonce, recvbuffer + CF_RSA_PROTO_OFFSET, nonce_len);
    }

/* Client's ID is now established by key or trusted, reply with digest */

    HashString(decrypted_nonce, nonce_len, digest, digestType);

    free(decrypted_nonce);

/* Get the public key from the client */
    newkey = RSA_new();

/* proposition C2 */
    if ((len_n = ReceiveTransaction(conn->conn_info, recvbuffer, NULL)) == -1)
    {
        Log(LOG_LEVEL_INFO, "Protocol error 1 in RSA authentation from IP %s", conn->hostname);
        RSA_free(newkey);
        return false;
    }

    if (len_n == 0)
    {
        Log(LOG_LEVEL_INFO, "Protocol error 2 in RSA authentation from IP %s", conn->hostname);
        RSA_free(newkey);
        return false;
    }

    if ((newkey->n = BN_mpi2bn(recvbuffer, len_n, NULL)) == NULL)
    {
        err = ERR_get_error();
        Log(LOG_LEVEL_ERR, "Private decrypt failed = %s", ERR_reason_error_string(err));
        RSA_free(newkey);
        return false;
    }

/* proposition C3 */

    if ((len_e = ReceiveTransaction(conn->conn_info, recvbuffer, NULL)) == -1)
    {
        Log(LOG_LEVEL_INFO, "Protocol error 3 in RSA authentation from IP %s", conn->hostname);
        RSA_free(newkey);
        return false;
    }

    if (len_e == 0)
    {
        Log(LOG_LEVEL_INFO, "Protocol error 4 in RSA authentation from IP %s", conn->hostname);
        RSA_free(newkey);
        return false;
    }

    if ((newkey->e = BN_mpi2bn(recvbuffer, len_e, NULL)) == NULL)
    {
        err = ERR_get_error();
        Log(LOG_LEVEL_ERR, "Private decrypt failed = %s", ERR_reason_error_string(err));
        RSA_free(newkey);
        return false;
    }

    /* Compute and store hash of the client's public key. */
    Key *key = KeyNew(newkey, CF_DEFAULT_DIGEST);
    ConnectionInfoSetKey(conn->conn_info, key);
    Log(LOG_LEVEL_VERBOSE, "Public key identity of host '%s' is '%s'",
        conn->ipaddr, KeyPrintableHash(ConnectionInfoKey(conn->conn_info)));

    LastSaw1(conn->ipaddr, KeyPrintableHash(ConnectionInfoKey(conn->conn_info)),
             LAST_SEEN_ROLE_ACCEPT);

    if (!CheckStoreKey(conn, newkey))   /* conceals proposition S1 */
    {
        return false;
    }

/* Reply with digest of original challenge */

/* proposition S2 */

    SendTransaction(conn->conn_info, digest, digestLen, CF_DONE);

/* Send counter challenge to be sure this is a live session */

    counter_challenge = BN_new();
    if (counter_challenge == NULL)
    {
        Log(LOG_LEVEL_ERR, "Cannot allocate BIGNUM structure for counter challenge");
        return false;
    }

    BN_rand(counter_challenge, CF_NONCELEN, 0, 0);
    nonce_len = BN_bn2mpi(counter_challenge, in);

// hash the challenge from the client

    HashString(in, nonce_len, digest, digestType);

    encrypted_len = RSA_size(newkey);   /* encryption buffer is always the same size as n */

    out = xmalloc(encrypted_len + 1);

    if (RSA_public_encrypt(nonce_len, in, out, newkey, RSA_PKCS1_PADDING) <= 0)
    {
        err = ERR_get_error();
        Log(LOG_LEVEL_ERR, "Public encryption failed = %s", ERR_reason_error_string(err));
        free(out);
        return false;
    }

/* proposition S3 */
    SendTransaction(conn->conn_info, out, encrypted_len, CF_DONE);

/* if the client doesn't have our public key, send it */

    if (iscrypt != 'y')
    {
        /* proposition S4  - conditional */
        memset(in, 0, CF_BUFSIZE);
        len_n = BN_bn2mpi(PUBKEY->n, in);
        SendTransaction(conn->conn_info, in, len_n, CF_DONE);

        /* proposition S5  - conditional */
        memset(in, 0, CF_BUFSIZE);
        len_e = BN_bn2mpi(PUBKEY->e, in);
        SendTransaction(conn->conn_info, in, len_e, CF_DONE);
    }

/* Receive reply to counter_challenge */

/* proposition C4 */
    memset(in, 0, CF_BUFSIZE);

    if (ReceiveTransaction(conn->conn_info, in, NULL) == -1)
    {
        BN_free(counter_challenge);
        free(out);
        return false;
    }

    if (HashesMatch(digest, in, digestType))    /* replay / piggy in the middle attack ? */
    {
        Log(LOG_LEVEL_VERBOSE, "Authentication of client %s/%s achieved", conn->hostname, conn->ipaddr);
    }
    else
    {
        BN_free(counter_challenge);
        free(out);
        Log(LOG_LEVEL_INFO, "Challenge response from client %s was incorrect - ID false?", conn->ipaddr);
        return false;
    }

/* Receive random session key,... */

/* proposition C5 */

    memset(in, 0, CF_BUFSIZE);

    if ((keylen = ReceiveTransaction(conn->conn_info, in, NULL)) == -1)
    {
        BN_free(counter_challenge);
        free(out);
        return false;
    }

    if (keylen > CF_BUFSIZE / 2)
    {
        BN_free(counter_challenge);
        free(out);
        Log(LOG_LEVEL_INFO, "Session key length received from %s is too long", conn->ipaddr);
        return false;
    }

    session_size = CfSessionKeySize(enterprise_field);
    conn->session_key = xmalloc(session_size);
    conn->encryption_type = enterprise_field;

    Log(LOG_LEVEL_VERBOSE, "Receiving session key from client (size=%d)...", keylen);

    Log(LOG_LEVEL_DEBUG, "keylen = %d, session_size = %d", keylen, session_size);

    if (keylen == CF_BLOWFISHSIZE)      /* Support the old non-ecnrypted for upgrade */
    {
        memcpy(conn->session_key, in, session_size);
    }
    else
    {
        /* New protocol encrypted */

        if (RSA_private_decrypt(keylen, in, out, PRIVKEY, RSA_PKCS1_PADDING) <= 0)
        {
            err = ERR_get_error();
            Log(LOG_LEVEL_ERR, "Private decrypt failed = %s", ERR_reason_error_string(err));
            BN_free(counter_challenge);
            free(out);
            return false;
        }

        memcpy(conn->session_key, out, session_size);
    }

    BN_free(counter_challenge);
    free(out);
    return true;
}
Ejemplo n.º 3
0
int AuthenticateAgent(AgentConnection *conn, bool trust_key)
{
    char sendbuffer[CF_EXPANDSIZE], in[CF_BUFSIZE], *out, *decrypted_cchall;
    BIGNUM *nonce_challenge, *bn = NULL;
    unsigned char digest[EVP_MAX_MD_SIZE];
    int encrypted_len, nonce_len = 0, len, session_size;
    bool need_to_implicitly_trust_server;
    char enterprise_field = 'c';
    RSA *server_pubkey = NULL;

    if ((PUBKEY == NULL) || (PRIVKEY == NULL))
    {
        /* Try once more to load the keys, maybe the system is converging. */
        LoadSecretKeys();
        if ((PUBKEY == NULL) || (PRIVKEY == NULL))
        {
            char *pubkeyfile = PublicKeyFile(GetWorkDir());
            Log(LOG_LEVEL_ERR, "No public/private key pair found at: %s", pubkeyfile);
            free(pubkeyfile);
            return false;
        }
    }

    enterprise_field = CfEnterpriseOptions();
    session_size = CfSessionKeySize(enterprise_field);

/* Generate a random challenge to authenticate the server */

    nonce_challenge = BN_new();
    if (nonce_challenge == NULL)
    {
        Log(LOG_LEVEL_ERR, "Cannot allocate BIGNUM structure for server challenge");
        return false;
    }

    BN_rand(nonce_challenge, CF_NONCELEN, 0, 0);
    nonce_len = BN_bn2mpi(nonce_challenge, in);

    if (FIPS_MODE)
    {
        HashString(in, nonce_len, digest, CF_DEFAULT_DIGEST);
    }
    else
    {
        HashString(in, nonce_len, digest, HASH_METHOD_MD5);
    }

/* We assume that the server bound to the remote socket is the official one i.e. = root's */

    /* Ask the server to send us the public key if we don't have it. */
    if ((server_pubkey = HavePublicKeyByIP(conn->username, conn->remoteip)))
    {
        need_to_implicitly_trust_server = false;
        encrypted_len = RSA_size(server_pubkey);
    }
    else
    {
        need_to_implicitly_trust_server = true;
        encrypted_len = nonce_len;
    }

// Server pubkey is what we want to has as a unique ID

    snprintf(sendbuffer, sizeof(sendbuffer), "SAUTH %c %d %d %c",
             need_to_implicitly_trust_server ? 'n': 'y',
             encrypted_len, nonce_len, enterprise_field);

    out = xmalloc(encrypted_len);

    if (server_pubkey != NULL)
    {
        if (RSA_public_encrypt(nonce_len, in, out, server_pubkey, RSA_PKCS1_PADDING) <= 0)
        {
            Log(LOG_LEVEL_ERR,
                "Public encryption failed. (RSA_public_encrypt: %s)",
            CryptoLastErrorString());
            free(out);
            RSA_free(server_pubkey);
            return false;
        }

        memcpy(sendbuffer + CF_RSA_PROTO_OFFSET, out, encrypted_len);
    }
    else
    {
        memcpy(sendbuffer + CF_RSA_PROTO_OFFSET, in, nonce_len);
    }

/* proposition C1 - Send challenge / nonce */

    SendTransaction(conn->conn_info, sendbuffer, CF_RSA_PROTO_OFFSET + encrypted_len, CF_DONE);

    BN_free(bn);
    BN_free(nonce_challenge);
    free(out);

/*Send the public key - we don't know if server has it */
/* proposition C2 */

    memset(sendbuffer, 0, CF_EXPANDSIZE);
    len = BN_bn2mpi(PUBKEY->n, sendbuffer);
    SendTransaction(conn->conn_info, sendbuffer, len, CF_DONE);        /* No need to encrypt the public key ... */

/* proposition C3 */
    memset(sendbuffer, 0, CF_EXPANDSIZE);
    len = BN_bn2mpi(PUBKEY->e, sendbuffer);
    SendTransaction(conn->conn_info, sendbuffer, len, CF_DONE);

/* check reply about public key - server can break conn_info here */

/* proposition S1 */
    memset(in, 0, CF_BUFSIZE);

    if (ReceiveTransaction(conn->conn_info, in, NULL) == -1)
    {
        Log(LOG_LEVEL_ERR, "Protocol transaction broken off (1). (ReceiveTransaction: %s)", GetErrorStr());
        RSA_free(server_pubkey);
        return false;
    }

    if (BadProtoReply(in))
    {
        Log(LOG_LEVEL_ERR, "Bad protocol reply: %s", in);
        RSA_free(server_pubkey);
        return false;
    }

/* Get challenge response - should be CF_DEFAULT_DIGEST of challenge */

/* proposition S2 */
    memset(in, 0, CF_BUFSIZE);

    if (ReceiveTransaction(conn->conn_info, in, NULL) == -1)
    {
        Log(LOG_LEVEL_ERR, "Protocol transaction broken off (2). (ReceiveTransaction: %s)", GetErrorStr());
        RSA_free(server_pubkey);
        return false;
    }

    /* Check if challenge reply was correct */
    if ((HashesMatch(digest, in, CF_DEFAULT_DIGEST)) ||
        (HashesMatch(digest, in, HASH_METHOD_MD5)))  // Legacy
    {
        if (need_to_implicitly_trust_server == false)
        {
            /* The IP was found in lastseen. */
            Log(LOG_LEVEL_VERBOSE,
                ".....................[.h.a.i.l.].................................");
            Log(LOG_LEVEL_VERBOSE,
                "Strong authentication of server '%s' connection confirmed",
                conn->this_server);
        }
        else                                /* IP was not found in lastseen */
        {
            if (trust_key)
            {
                Log(LOG_LEVEL_VERBOSE,
                    "Trusting server identity, promise to accept key from '%s' = '%s'",
                    conn->this_server, conn->remoteip);
            }
            else
            {
                Log(LOG_LEVEL_ERR,
                    "Not authorized to trust public key of server '%s' (trustkey = false)",
                    conn->this_server);
                RSA_free(server_pubkey);
                return false;
            }
        }
    }
    else
    {
        Log(LOG_LEVEL_ERR, "Challenge response from server '%s/%s' was incorrect", conn->this_server,
             conn->remoteip);
        RSA_free(server_pubkey);
        return false;
    }

/* Receive counter challenge from server */

/* proposition S3 */
    memset(in, 0, CF_BUFSIZE);
    encrypted_len = ReceiveTransaction(conn->conn_info, in, NULL);

    if (encrypted_len <= 0)
    {
        Log(LOG_LEVEL_ERR, "Protocol transaction sent illegal cipher length");
        RSA_free(server_pubkey);
        return false;
    }

    decrypted_cchall = xmalloc(encrypted_len);

    if (RSA_private_decrypt(encrypted_len, in, decrypted_cchall, PRIVKEY, RSA_PKCS1_PADDING) <= 0)
    {
        Log(LOG_LEVEL_ERR,
            "Private decrypt failed, abandoning. (RSA_private_decrypt: %s)",
            CryptoLastErrorString());
        RSA_free(server_pubkey);
        return false;
    }

/* proposition C4 */
    if (FIPS_MODE)
    {
        HashString(decrypted_cchall, nonce_len, digest, CF_DEFAULT_DIGEST);
    }
    else
    {
        HashString(decrypted_cchall, nonce_len, digest, HASH_METHOD_MD5);
    }

    if (FIPS_MODE)
    {
        SendTransaction(conn->conn_info, digest, CF_DEFAULT_DIGEST_LEN, CF_DONE);
    }
    else
    {
        SendTransaction(conn->conn_info, digest, CF_MD5_LEN, CF_DONE);
    }

    free(decrypted_cchall);

/* If we don't have the server's public key, it will be sent */

    if (server_pubkey == NULL)
    {
        RSA *newkey = RSA_new();

        Log(LOG_LEVEL_VERBOSE, "Collecting public key from server!");

        /* proposition S4 - conditional */
        if ((len = ReceiveTransaction(conn->conn_info, in, NULL)) <= 0)
        {
            Log(LOG_LEVEL_ERR, "Protocol error in RSA authentation from IP '%s'", conn->this_server);
            return false;
        }

        if ((newkey->n = BN_mpi2bn(in, len, NULL)) == NULL)
        {
            Log(LOG_LEVEL_ERR,
                "Private key decrypt failed. (BN_mpi2bn: %s)",
                CryptoLastErrorString());
            RSA_free(newkey);
            return false;
        }

        /* proposition S5 - conditional */

        if ((len = ReceiveTransaction(conn->conn_info, in, NULL)) <= 0)
        {
            Log(LOG_LEVEL_INFO, "Protocol error in RSA authentation from IP '%s'",
                 conn->this_server);
            RSA_free(newkey);
            return false;
        }

        if ((newkey->e = BN_mpi2bn(in, len, NULL)) == NULL)
        {
            Log(LOG_LEVEL_ERR,
                "Public key decrypt failed. (BN_mpi2bn: %s)",
                CryptoLastErrorString());
            RSA_free(newkey);
            return false;
        }

        server_pubkey = RSAPublicKey_dup(newkey);
        RSA_free(newkey);
    }
    assert(server_pubkey != NULL);

/* proposition C5 */

    if (!SetSessionKey(conn))
    {
        Log(LOG_LEVEL_ERR, "Unable to set session key");
        return false;
    }

    if (conn->session_key == NULL)
    {
        Log(LOG_LEVEL_ERR, "A random session key could not be established");
        RSA_free(server_pubkey);
        return false;
    }

    encrypted_len = RSA_size(server_pubkey);

    out = xmalloc(encrypted_len);

    if (RSA_public_encrypt(session_size, conn->session_key, out, server_pubkey, RSA_PKCS1_PADDING) <= 0)
    {
        Log(LOG_LEVEL_ERR,
            "Public encryption failed. (RSA_public_encrypt: %s)",
            CryptoLastErrorString());
        free(out);
        RSA_free(server_pubkey);
        return false;
    }

    SendTransaction(conn->conn_info, out, encrypted_len, CF_DONE);

    Key *key = KeyNew(server_pubkey, CF_DEFAULT_DIGEST);
    conn->conn_info->remote_key = key;

    Log(LOG_LEVEL_VERBOSE, "Public key identity of host '%s' is: %s",
        conn->remoteip, KeyPrintableHash(conn->conn_info->remote_key));

    SavePublicKey(conn->username, KeyPrintableHash(conn->conn_info->remote_key), server_pubkey);

    unsigned int length = 0;
    LastSaw(conn->remoteip, KeyBinaryHash(conn->conn_info->remote_key, &length), LAST_SEEN_ROLE_CONNECT);

    free(out);

    return true;
}
Ejemplo n.º 4
0
static PromiseResult RenderTemplateMustache(EvalContext *ctx, const Promise *pp, Attributes a,
                                            EditContext *edcontext)
{
    PromiseResult result = PROMISE_RESULT_NOOP;

    if (!FileCanOpen(a.edit_template, "r"))
    {
        cfPS(ctx, LOG_LEVEL_ERR, PROMISE_RESULT_FAIL, pp, a, "Template file '%s' could not be opened for reading", a.edit_template);
        return PromiseResultUpdate(result, PROMISE_RESULT_FAIL);
    }

    unsigned char existing_output_digest[EVP_MAX_MD_SIZE + 1] = { 0 };
    if (access(pp->promiser, R_OK) == 0)
    {
        HashFile(pp->promiser, existing_output_digest, CF_DEFAULT_DIGEST);
    }

    int template_fd = safe_open(a.edit_template, O_RDONLY | O_TEXT);
    Writer *template_writer = NULL;
    if (template_fd >= 0)
    {
        template_writer = FileReadFromFd(template_fd, SIZE_MAX, NULL);
        close(template_fd);
    }
    if (!template_writer)
    {
        cfPS(ctx, LOG_LEVEL_ERR, PROMISE_RESULT_FAIL, pp, a, "Could not read template file '%s'", a.edit_template);
        return PromiseResultUpdate(result, PROMISE_RESULT_FAIL);
    }

    JsonElement *default_template_data = NULL;
    if (!a.template_data)
    {
        a.template_data = default_template_data = DefaultTemplateData(ctx);
    }

    Buffer *output_buffer = BufferNew();
    if (MustacheRender(output_buffer, StringWriterData(template_writer), a.template_data))
    {
        unsigned char rendered_output_digest[EVP_MAX_MD_SIZE + 1] = { 0 };
        HashString(BufferData(output_buffer), BufferSize(output_buffer), rendered_output_digest, CF_DEFAULT_DIGEST);
        if (!HashesMatch(existing_output_digest, rendered_output_digest, CF_DEFAULT_DIGEST))
        {
            if (SaveAsFile(SaveBufferCallback, output_buffer, edcontext->filename, a, edcontext->new_line_mode))
            {
                cfPS(ctx, LOG_LEVEL_INFO, PROMISE_RESULT_CHANGE, pp, a, "Updated rendering of '%s' from template mustache template '%s'",
                     pp->promiser, a.edit_template);
                result = PromiseResultUpdate(result, PROMISE_RESULT_CHANGE);
            }
            else
            {
                cfPS(ctx, LOG_LEVEL_INFO, PROMISE_RESULT_FAIL, pp, a, "Updated rendering of '%s' from template mustache template '%s'",
                     pp->promiser, a.edit_template);
                result = PromiseResultUpdate(result, PROMISE_RESULT_FAIL);
            }
        }

        JsonDestroy(default_template_data);
        WriterClose(template_writer);
        BufferDestroy(output_buffer);

        return result;
    }
    else
    {
        cfPS(ctx, LOG_LEVEL_ERR, PROMISE_RESULT_FAIL, pp, a, "Error rendering mustache template '%s'", a.edit_template);
        result = PromiseResultUpdate(result, PROMISE_RESULT_FAIL);
        JsonDestroy(default_template_data);
        WriterClose(template_writer);
        BufferDestroy(output_buffer);
        return PromiseResultUpdate(result, PROMISE_RESULT_FAIL);
    }
}
Ejemplo n.º 5
0
int AuthenticateAgent(AgentConnection *conn, bool trust_key)
{
    char sendbuffer[CF_EXPANDSIZE], in[CF_BUFSIZE], *out, *decrypted_cchall;
    BIGNUM *nonce_challenge, *bn = NULL;
    unsigned long err;
    unsigned char digest[EVP_MAX_MD_SIZE];
    int encrypted_len, nonce_len = 0, len, session_size;
    bool implicitly_trust_server;
    char enterprise_field = 'c';
    RSA *server_pubkey = NULL;

    if ((PUBKEY == NULL) || (PRIVKEY == NULL))
    {
        Log(LOG_LEVEL_ERR, "No public/private key pair found at %s", PublicKeyFile(GetWorkDir()));
        return false;
    }

    enterprise_field = CfEnterpriseOptions();
    session_size = CfSessionKeySize(enterprise_field);

/* Generate a random challenge to authenticate the server */

    nonce_challenge = BN_new();
    if (nonce_challenge == NULL)
    {
        Log(LOG_LEVEL_ERR, "Cannot allocate BIGNUM structure for server challenge");
        return false;
    }

    BN_rand(nonce_challenge, CF_NONCELEN, 0, 0);
    nonce_len = BN_bn2mpi(nonce_challenge, in);

    if (FIPS_MODE)
    {
        HashString(in, nonce_len, digest, CF_DEFAULT_DIGEST);
    }
    else
    {
        HashString(in, nonce_len, digest, HASH_METHOD_MD5);
    }

/* We assume that the server bound to the remote socket is the official one i.e. = root's */

    if ((server_pubkey = HavePublicKeyByIP(conn->username, conn->remoteip)))
    {
        implicitly_trust_server = false;
        encrypted_len = RSA_size(server_pubkey);
    }
    else
    {
        implicitly_trust_server = true;
        encrypted_len = nonce_len;
    }

// Server pubkey is what we want to has as a unique ID

    snprintf(sendbuffer, sizeof(sendbuffer), "SAUTH %c %d %d %c", implicitly_trust_server ? 'n': 'y', encrypted_len,
             nonce_len, enterprise_field);

    out = xmalloc(encrypted_len);

    if (server_pubkey != NULL)
    {
        if (RSA_public_encrypt(nonce_len, in, out, server_pubkey, RSA_PKCS1_PADDING) <= 0)
        {
            err = ERR_get_error();
            Log(LOG_LEVEL_ERR, "Public encryption failed = %s", ERR_reason_error_string(err));
            free(out);
            RSA_free(server_pubkey);
            return false;
        }

        memcpy(sendbuffer + CF_RSA_PROTO_OFFSET, out, encrypted_len);
    }
    else
    {
        memcpy(sendbuffer + CF_RSA_PROTO_OFFSET, in, nonce_len);
    }

/* proposition C1 - Send challenge / nonce */

    SendTransaction(conn->sd, sendbuffer, CF_RSA_PROTO_OFFSET + encrypted_len, CF_DONE);

    BN_free(bn);
    BN_free(nonce_challenge);
    free(out);

    if (DEBUG)
    {
        RSA_print_fp(stdout, PUBKEY, 0);
    }

/*Send the public key - we don't know if server has it */
/* proposition C2 */

    memset(sendbuffer, 0, CF_EXPANDSIZE);
    len = BN_bn2mpi(PUBKEY->n, sendbuffer);
    SendTransaction(conn->sd, sendbuffer, len, CF_DONE);        /* No need to encrypt the public key ... */

/* proposition C3 */
    memset(sendbuffer, 0, CF_EXPANDSIZE);
    len = BN_bn2mpi(PUBKEY->e, sendbuffer);
    SendTransaction(conn->sd, sendbuffer, len, CF_DONE);

/* check reply about public key - server can break connection here */

/* proposition S1 */
    memset(in, 0, CF_BUFSIZE);

    if (ReceiveTransaction(conn->sd, in, NULL) == -1)
    {
        Log(LOG_LEVEL_ERR, "Protocol transaction broken off (1): %s", GetErrorStr());
        RSA_free(server_pubkey);
        return false;
    }

    if (BadProtoReply(in))
    {
        Log(LOG_LEVEL_ERR, "%s", in);
        RSA_free(server_pubkey);
        return false;
    }

/* Get challenge response - should be CF_DEFAULT_DIGEST of challenge */

/* proposition S2 */
    memset(in, 0, CF_BUFSIZE);

    if (ReceiveTransaction(conn->sd, in, NULL) == -1)
    {
        Log(LOG_LEVEL_ERR, "Protocol transaction broken off (2): %s", GetErrorStr());
        RSA_free(server_pubkey);
        return false;
    }

    if ((HashesMatch(digest, in, CF_DEFAULT_DIGEST)) || (HashesMatch(digest, in, HASH_METHOD_MD5)))  // Legacy
    {
        if (implicitly_trust_server == false)        /* challenge reply was correct */
        {
            Log(LOG_LEVEL_VERBOSE, ".....................[.h.a.i.l.].................................");
            Log(LOG_LEVEL_VERBOSE, "Strong authentication of server=%s connection confirmed", conn->this_server);
        }
        else
        {
            if (trust_key)
            {
                Log(LOG_LEVEL_VERBOSE, " -> Trusting server identity, promise to accept key from %s=%s", conn->this_server,
                      conn->remoteip);
            }
            else
            {
                Log(LOG_LEVEL_ERR, " !! Not authorized to trust the server=%s's public key (trustkey=false)",
                      conn->this_server);
                RSA_free(server_pubkey);
                return false;
            }
        }
    }
    else
    {
        Log(LOG_LEVEL_ERR, "Challenge response from server %s/%s was incorrect!", conn->this_server,
             conn->remoteip);
        RSA_free(server_pubkey);
        return false;
    }

/* Receive counter challenge from server */

/* proposition S3 */
    memset(in, 0, CF_BUFSIZE);
    encrypted_len = ReceiveTransaction(conn->sd, in, NULL);

    if (encrypted_len <= 0)
    {
        Log(LOG_LEVEL_ERR, "Protocol transaction sent illegal cipher length");
        RSA_free(server_pubkey);
        return false;
    }

    decrypted_cchall = xmalloc(encrypted_len);

    if (RSA_private_decrypt(encrypted_len, in, decrypted_cchall, PRIVKEY, RSA_PKCS1_PADDING) <= 0)
    {
        err = ERR_get_error();
        Log(LOG_LEVEL_ERR, "Private decrypt failed = %s, abandoning",
             ERR_reason_error_string(err));
        RSA_free(server_pubkey);
        return false;
    }

/* proposition C4 */
    if (FIPS_MODE)
    {
        HashString(decrypted_cchall, nonce_len, digest, CF_DEFAULT_DIGEST);
    }
    else
    {
        HashString(decrypted_cchall, nonce_len, digest, HASH_METHOD_MD5);
    }

    if (FIPS_MODE)
    {
        SendTransaction(conn->sd, digest, CF_DEFAULT_DIGEST_LEN, CF_DONE);
    }
    else
    {
        SendTransaction(conn->sd, digest, CF_MD5_LEN, CF_DONE);
    }

    free(decrypted_cchall);

/* If we don't have the server's public key, it will be sent */

    if (server_pubkey == NULL)
    {
        RSA *newkey = RSA_new();

        Log(LOG_LEVEL_VERBOSE, " -> Collecting public key from server!");

        /* proposition S4 - conditional */
        if ((len = ReceiveTransaction(conn->sd, in, NULL)) <= 0)
        {
            Log(LOG_LEVEL_ERR, "Protocol error in RSA authentation from IP %s", conn->this_server);
            return false;
        }

        if ((newkey->n = BN_mpi2bn(in, len, NULL)) == NULL)
        {
            err = ERR_get_error();
            Log(LOG_LEVEL_ERR, "Private key decrypt failed = %s", ERR_reason_error_string(err));
            RSA_free(newkey);
            return false;
        }

        /* proposition S5 - conditional */

        if ((len = ReceiveTransaction(conn->sd, in, NULL)) <= 0)
        {
            Log(LOG_LEVEL_INFO, "Protocol error in RSA authentation from IP %s",
                 conn->this_server);
            RSA_free(newkey);
            return false;
        }

        if ((newkey->e = BN_mpi2bn(in, len, NULL)) == NULL)
        {
            err = ERR_get_error();
            Log(LOG_LEVEL_ERR, "Public key decrypt failed = %s", ERR_reason_error_string(err));
            RSA_free(newkey);
            return false;
        }

        server_pubkey = RSAPublicKey_dup(newkey);
        RSA_free(newkey);
    }

/* proposition C5 */

    if (!SetSessionKey(conn))
    {
        Log(LOG_LEVEL_ERR, "Unable to set session key");
        return false;
    }

    if (conn->session_key == NULL)
    {
        Log(LOG_LEVEL_ERR, "A random session key could not be established");
        RSA_free(server_pubkey);
        return false;
    }

    encrypted_len = RSA_size(server_pubkey);

    out = xmalloc(encrypted_len);

    if (RSA_public_encrypt(session_size, conn->session_key, out, server_pubkey, RSA_PKCS1_PADDING) <= 0)
    {
        err = ERR_get_error();
        Log(LOG_LEVEL_ERR, "Public encryption failed = %s", ERR_reason_error_string(err));
        free(out);
        RSA_free(server_pubkey);
        return false;
    }

    SendTransaction(conn->sd, out, encrypted_len, CF_DONE);

    if (server_pubkey != NULL)
    {
        char buffer[EVP_MAX_MD_SIZE * 4];
        HashPubKey(server_pubkey, conn->digest, CF_DEFAULT_DIGEST);
        Log(LOG_LEVEL_VERBOSE, " -> Public key identity of host \"%s\" is \"%s\"", conn->remoteip,
              HashPrintSafe(CF_DEFAULT_DIGEST, conn->digest, buffer));
        SavePublicKey(conn->username, conn->remoteip, buffer, server_pubkey);       // FIXME: username is local
        LastSaw(conn->remoteip, conn->digest, LAST_SEEN_ROLE_CONNECT);
    }

    free(out);
    RSA_free(server_pubkey);

    return true;
}
Ejemplo n.º 6
0
int AuthenticateAgent(AgentConnection *conn, Attributes attr, Promise *pp)
{
    char sendbuffer[CF_EXPANDSIZE], in[CF_BUFSIZE], *out, *decrypted_cchall;
    BIGNUM *nonce_challenge, *bn = NULL;
    unsigned long err;
    unsigned char digest[EVP_MAX_MD_SIZE];
    int encrypted_len, nonce_len = 0, len, session_size;
    char dont_implicitly_trust_server, enterprise_field = 'c';
    RSA *server_pubkey = NULL;

    if (PUBKEY == NULL || PRIVKEY == NULL)
    {
        CfOut(cf_error, "", "No public/private key pair found\n");
        return false;
    }

    enterprise_field = CfEnterpriseOptions();
    session_size = CfSessionKeySize(enterprise_field);

/* Generate a random challenge to authenticate the server */

    nonce_challenge = BN_new();
    BN_rand(nonce_challenge, CF_NONCELEN, 0, 0);
    nonce_len = BN_bn2mpi(nonce_challenge, in);

    if (FIPS_MODE)
    {
        HashString(in, nonce_len, digest, CF_DEFAULT_DIGEST);
    }
    else
    {
        HashString(in, nonce_len, digest, cf_md5);
    }

/* We assume that the server bound to the remote socket is the official one i.e. = root's */

    if ((server_pubkey = HavePublicKeyByIP(conn->username, conn->remoteip)))
    {
        dont_implicitly_trust_server = 'y';
        encrypted_len = RSA_size(server_pubkey);
    }
    else
    {
        dont_implicitly_trust_server = 'n';     /* have to trust server, since we can't verify id */
        encrypted_len = nonce_len;
    }

// Server pubkey is what we want to has as a unique ID

    snprintf(sendbuffer, sizeof(sendbuffer), "SAUTH %c %d %d %c", dont_implicitly_trust_server, encrypted_len,
             nonce_len, enterprise_field);

    out = xmalloc(encrypted_len);

    if (server_pubkey != NULL)
    {
        if (RSA_public_encrypt(nonce_len, in, out, server_pubkey, RSA_PKCS1_PADDING) <= 0)
        {
            err = ERR_get_error();
            cfPS(cf_error, CF_FAIL, "", pp, attr, "Public encryption failed = %s\n", ERR_reason_error_string(err));
            free(out);
            FreeRSAKey(server_pubkey);
            return false;
        }

        memcpy(sendbuffer + CF_RSA_PROTO_OFFSET, out, encrypted_len);
    }
    else
    {
        memcpy(sendbuffer + CF_RSA_PROTO_OFFSET, in, nonce_len);
    }

/* proposition C1 - Send challenge / nonce */

    SendTransaction(conn->sd, sendbuffer, CF_RSA_PROTO_OFFSET + encrypted_len, CF_DONE);

    BN_free(bn);
    BN_free(nonce_challenge);
    free(out);

    if (DEBUG)
    {
        RSA_print_fp(stdout, PUBKEY, 0);
    }

/*Send the public key - we don't know if server has it */
/* proposition C2 */

    memset(sendbuffer, 0, CF_EXPANDSIZE);
    len = BN_bn2mpi(PUBKEY->n, sendbuffer);
    SendTransaction(conn->sd, sendbuffer, len, CF_DONE);        /* No need to encrypt the public key ... */

/* proposition C3 */
    memset(sendbuffer, 0, CF_EXPANDSIZE);
    len = BN_bn2mpi(PUBKEY->e, sendbuffer);
    SendTransaction(conn->sd, sendbuffer, len, CF_DONE);

/* check reply about public key - server can break connection here */

/* proposition S1 */
    memset(in, 0, CF_BUFSIZE);

    if (ReceiveTransaction(conn->sd, in, NULL) == -1)
    {
        cfPS(cf_error, CF_INTERPT, "recv", pp, attr, "Protocol transaction broken off (1)");
        FreeRSAKey(server_pubkey);
        return false;
    }

    if (BadProtoReply(in))
    {
        CfOut(cf_error, "", "%s", in);
        FreeRSAKey(server_pubkey);
        return false;
    }

/* Get challenge response - should be CF_DEFAULT_DIGEST of challenge */

/* proposition S2 */
    memset(in, 0, CF_BUFSIZE);

    if (ReceiveTransaction(conn->sd, in, NULL) == -1)
    {
        cfPS(cf_error, CF_INTERPT, "recv", pp, attr, "Protocol transaction broken off (2)");
        FreeRSAKey(server_pubkey);
        return false;
    }

    if (HashesMatch(digest, in, CF_DEFAULT_DIGEST) || HashesMatch(digest, in, cf_md5))  // Legacy
    {
        if (dont_implicitly_trust_server == 'y')        /* challenge reply was correct */
        {
            CfOut(cf_verbose, "", ".....................[.h.a.i.l.].................................\n");
            CfOut(cf_verbose, "", "Strong authentication of server=%s connection confirmed\n", pp->this_server);
        }
        else
        {
            if (attr.copy.trustkey)
            {
                CfOut(cf_verbose, "", " -> Trusting server identity, promise to accept key from %s=%s", pp->this_server,
                      conn->remoteip);
            }
            else
            {
                CfOut(cf_error, "", " !! Not authorized to trust the server=%s's public key (trustkey=false)\n",
                      pp->this_server);
                PromiseRef(cf_verbose, pp);
                FreeRSAKey(server_pubkey);
                return false;
            }
        }
    }
    else
    {
        cfPS(cf_error, CF_INTERPT, "", pp, attr, "Challenge response from server %s/%s was incorrect!", pp->this_server,
             conn->remoteip);
        FreeRSAKey(server_pubkey);
        return false;
    }

/* Receive counter challenge from server */

    CfDebug("Receive counter challenge from server\n");

/* proposition S3 */
    memset(in, 0, CF_BUFSIZE);
    encrypted_len = ReceiveTransaction(conn->sd, in, NULL);

    if (encrypted_len <= 0)
    {
        CfOut(cf_error, "", "Protocol transaction sent illegal cipher length");
        FreeRSAKey(server_pubkey);
        return false;
    }

    decrypted_cchall = xmalloc(encrypted_len);

    if (RSA_private_decrypt(encrypted_len, in, decrypted_cchall, PRIVKEY, RSA_PKCS1_PADDING) <= 0)
    {
        err = ERR_get_error();
        cfPS(cf_error, CF_INTERPT, "", pp, attr, "Private decrypt failed = %s, abandoning\n",
             ERR_reason_error_string(err));
        FreeRSAKey(server_pubkey);
        return false;
    }

/* proposition C4 */
    if (FIPS_MODE)
    {
        HashString(decrypted_cchall, nonce_len, digest, CF_DEFAULT_DIGEST);
    }
    else
    {
        HashString(decrypted_cchall, nonce_len, digest, cf_md5);
    }

    CfDebug("Replying to counter challenge with hash\n");

    if (FIPS_MODE)
    {
        SendTransaction(conn->sd, digest, CF_DEFAULT_DIGEST_LEN, CF_DONE);
    }
    else
    {
        SendTransaction(conn->sd, digest, CF_MD5_LEN, CF_DONE);
    }

    free(decrypted_cchall);

/* If we don't have the server's public key, it will be sent */

    if (server_pubkey == NULL)
    {
        RSA *newkey = RSA_new();

        CfOut(cf_verbose, "", " -> Collecting public key from server!\n");

        /* proposition S4 - conditional */
        if ((len = ReceiveTransaction(conn->sd, in, NULL)) <= 0)
        {
            CfOut(cf_error, "", "Protocol error in RSA authentation from IP %s\n", pp->this_server);
            return false;
        }

        if ((newkey->n = BN_mpi2bn(in, len, NULL)) == NULL)
        {
            err = ERR_get_error();
            cfPS(cf_error, CF_INTERPT, "", pp, attr, "Private key decrypt failed = %s\n", ERR_reason_error_string(err));
            FreeRSAKey(newkey);
            return false;
        }

        /* proposition S5 - conditional */

        if ((len = ReceiveTransaction(conn->sd, in, NULL)) <= 0)
        {
            cfPS(cf_inform, CF_INTERPT, "", pp, attr, "Protocol error in RSA authentation from IP %s\n",
                 pp->this_server);
            FreeRSAKey(newkey);
            return false;
        }

        if ((newkey->e = BN_mpi2bn(in, len, NULL)) == NULL)
        {
            err = ERR_get_error();
            cfPS(cf_error, CF_INTERPT, "", pp, attr, "Public key decrypt failed = %s\n", ERR_reason_error_string(err));
            FreeRSAKey(newkey);
            return false;
        }

        server_pubkey = RSAPublicKey_dup(newkey);
        FreeRSAKey(newkey);
    }

/* proposition C5 */

    SetSessionKey(conn);

    if (conn->session_key == NULL)
    {
        CfOut(cf_error, "", "A random session key could not be established");
        FreeRSAKey(server_pubkey);
        return false;
    }

    encrypted_len = RSA_size(server_pubkey);

    CfDebug("Encrypt %d bytes of session key into %d RSA bytes\n", session_size, encrypted_len);

    out = xmalloc(encrypted_len);

    if (RSA_public_encrypt(session_size, conn->session_key, out, server_pubkey, RSA_PKCS1_PADDING) <= 0)
    {
        err = ERR_get_error();
        cfPS(cf_error, CF_INTERPT, "", pp, attr, "Public encryption failed = %s\n", ERR_reason_error_string(err));
        free(out);
        FreeRSAKey(server_pubkey);
        return false;
    }

    SendTransaction(conn->sd, out, encrypted_len, CF_DONE);

    if (server_pubkey != NULL)
    {
        HashPubKey(server_pubkey, conn->digest, CF_DEFAULT_DIGEST);
        CfOut(cf_verbose, "", " -> Public key identity of host \"%s\" is \"%s\"", conn->remoteip,
              HashPrint(CF_DEFAULT_DIGEST, conn->digest));
        SavePublicKey(conn->username, conn->remoteip, HashPrint(CF_DEFAULT_DIGEST, conn->digest), server_pubkey);       // FIXME: username is local
        LastSaw(conn->remoteip, conn->digest, cf_connect);
    }

    free(out);
    FreeRSAKey(server_pubkey);
    return true;
}