diff options
author | des <des@FreeBSD.org> | 2008-07-22 19:01:18 +0000 |
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committer | des <des@FreeBSD.org> | 2008-07-22 19:01:18 +0000 |
commit | f1596419c2717cb81dd4b676d5e0cf1a3e30e98c (patch) | |
tree | 9827eb822991aa369cf5d220fce40c3d2011c19f /crypto/openssh/sshconnect1.c | |
parent | 666aa9cc1660793c97ef29a6cb66dfbb894dde8f (diff) | |
download | FreeBSD-src-f1596419c2717cb81dd4b676d5e0cf1a3e30e98c.zip FreeBSD-src-f1596419c2717cb81dd4b676d5e0cf1a3e30e98c.tar.gz |
Properly flatten openssh/dist.
Diffstat (limited to 'crypto/openssh/sshconnect1.c')
-rw-r--r-- | crypto/openssh/sshconnect1.c | 753 |
1 files changed, 0 insertions, 753 deletions
diff --git a/crypto/openssh/sshconnect1.c b/crypto/openssh/sshconnect1.c deleted file mode 100644 index fd07bbf..0000000 --- a/crypto/openssh/sshconnect1.c +++ /dev/null @@ -1,753 +0,0 @@ -/* $OpenBSD: sshconnect1.c,v 1.70 2006/11/06 21:25:28 markus Exp $ */ -/* - * Author: Tatu Ylonen <ylo@cs.hut.fi> - * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland - * All rights reserved - * Code to connect to a remote host, and to perform the client side of the - * login (authentication) dialog. - * - * As far as I am concerned, the code I have written for this software - * can be used freely for any purpose. Any derived versions of this - * software must be clearly marked as such, and if the derived work is - * incompatible with the protocol description in the RFC file, it must be - * called by a name other than "ssh" or "Secure Shell". - */ - -#include "includes.h" - -#include <sys/types.h> -#include <sys/socket.h> - -#include <openssl/bn.h> -#include <openssl/md5.h> - -#include <stdarg.h> -#include <stdio.h> -#include <stdlib.h> -#include <string.h> -#include <signal.h> -#include <pwd.h> - -#include "xmalloc.h" -#include "ssh.h" -#include "ssh1.h" -#include "rsa.h" -#include "buffer.h" -#include "packet.h" -#include "key.h" -#include "cipher.h" -#include "kex.h" -#include "uidswap.h" -#include "log.h" -#include "readconf.h" -#include "authfd.h" -#include "sshconnect.h" -#include "authfile.h" -#include "misc.h" -#include "canohost.h" -#include "hostfile.h" -#include "auth.h" - -/* Session id for the current session. */ -u_char session_id[16]; -u_int supported_authentications = 0; - -extern Options options; -extern char *__progname; - -/* - * Checks if the user has an authentication agent, and if so, tries to - * authenticate using the agent. - */ -static int -try_agent_authentication(void) -{ - int type; - char *comment; - AuthenticationConnection *auth; - u_char response[16]; - u_int i; - Key *key; - BIGNUM *challenge; - - /* Get connection to the agent. */ - auth = ssh_get_authentication_connection(); - if (!auth) - return 0; - - if ((challenge = BN_new()) == NULL) - fatal("try_agent_authentication: BN_new failed"); - /* Loop through identities served by the agent. */ - for (key = ssh_get_first_identity(auth, &comment, 1); - key != NULL; - key = ssh_get_next_identity(auth, &comment, 1)) { - - /* Try this identity. */ - debug("Trying RSA authentication via agent with '%.100s'", comment); - xfree(comment); - - /* Tell the server that we are willing to authenticate using this key. */ - packet_start(SSH_CMSG_AUTH_RSA); - packet_put_bignum(key->rsa->n); - packet_send(); - packet_write_wait(); - - /* Wait for server's response. */ - type = packet_read(); - - /* The server sends failure if it doesn't like our key or - does not support RSA authentication. */ - if (type == SSH_SMSG_FAILURE) { - debug("Server refused our key."); - key_free(key); - continue; - } - /* Otherwise it should have sent a challenge. */ - if (type != SSH_SMSG_AUTH_RSA_CHALLENGE) - packet_disconnect("Protocol error during RSA authentication: %d", - type); - - packet_get_bignum(challenge); - packet_check_eom(); - - debug("Received RSA challenge from server."); - - /* Ask the agent to decrypt the challenge. */ - if (!ssh_decrypt_challenge(auth, key, challenge, session_id, 1, response)) { - /* - * The agent failed to authenticate this identifier - * although it advertised it supports this. Just - * return a wrong value. - */ - logit("Authentication agent failed to decrypt challenge."); - memset(response, 0, sizeof(response)); - } - key_free(key); - debug("Sending response to RSA challenge."); - - /* Send the decrypted challenge back to the server. */ - packet_start(SSH_CMSG_AUTH_RSA_RESPONSE); - for (i = 0; i < 16; i++) - packet_put_char(response[i]); - packet_send(); - packet_write_wait(); - - /* Wait for response from the server. */ - type = packet_read(); - - /* The server returns success if it accepted the authentication. */ - if (type == SSH_SMSG_SUCCESS) { - ssh_close_authentication_connection(auth); - BN_clear_free(challenge); - debug("RSA authentication accepted by server."); - return 1; - } - /* Otherwise it should return failure. */ - if (type != SSH_SMSG_FAILURE) - packet_disconnect("Protocol error waiting RSA auth response: %d", - type); - } - ssh_close_authentication_connection(auth); - BN_clear_free(challenge); - debug("RSA authentication using agent refused."); - return 0; -} - -/* - * Computes the proper response to a RSA challenge, and sends the response to - * the server. - */ -static void -respond_to_rsa_challenge(BIGNUM * challenge, RSA * prv) -{ - u_char buf[32], response[16]; - MD5_CTX md; - int i, len; - - /* Decrypt the challenge using the private key. */ - /* XXX think about Bleichenbacher, too */ - if (rsa_private_decrypt(challenge, challenge, prv) <= 0) - packet_disconnect( - "respond_to_rsa_challenge: rsa_private_decrypt failed"); - - /* Compute the response. */ - /* The response is MD5 of decrypted challenge plus session id. */ - len = BN_num_bytes(challenge); - if (len <= 0 || (u_int)len > sizeof(buf)) - packet_disconnect( - "respond_to_rsa_challenge: bad challenge length %d", len); - - memset(buf, 0, sizeof(buf)); - BN_bn2bin(challenge, buf + sizeof(buf) - len); - MD5_Init(&md); - MD5_Update(&md, buf, 32); - MD5_Update(&md, session_id, 16); - MD5_Final(response, &md); - - debug("Sending response to host key RSA challenge."); - - /* Send the response back to the server. */ - packet_start(SSH_CMSG_AUTH_RSA_RESPONSE); - for (i = 0; i < 16; i++) - packet_put_char(response[i]); - packet_send(); - packet_write_wait(); - - memset(buf, 0, sizeof(buf)); - memset(response, 0, sizeof(response)); - memset(&md, 0, sizeof(md)); -} - -/* - * Checks if the user has authentication file, and if so, tries to authenticate - * the user using it. - */ -static int -try_rsa_authentication(int idx) -{ - BIGNUM *challenge; - Key *public, *private; - char buf[300], *passphrase, *comment, *authfile; - int i, perm_ok = 1, type, quit; - - public = options.identity_keys[idx]; - authfile = options.identity_files[idx]; - comment = xstrdup(authfile); - - debug("Trying RSA authentication with key '%.100s'", comment); - - /* Tell the server that we are willing to authenticate using this key. */ - packet_start(SSH_CMSG_AUTH_RSA); - packet_put_bignum(public->rsa->n); - packet_send(); - packet_write_wait(); - - /* Wait for server's response. */ - type = packet_read(); - - /* - * The server responds with failure if it doesn't like our key or - * doesn't support RSA authentication. - */ - if (type == SSH_SMSG_FAILURE) { - debug("Server refused our key."); - xfree(comment); - return 0; - } - /* Otherwise, the server should respond with a challenge. */ - if (type != SSH_SMSG_AUTH_RSA_CHALLENGE) - packet_disconnect("Protocol error during RSA authentication: %d", type); - - /* Get the challenge from the packet. */ - if ((challenge = BN_new()) == NULL) - fatal("try_rsa_authentication: BN_new failed"); - packet_get_bignum(challenge); - packet_check_eom(); - - debug("Received RSA challenge from server."); - - /* - * If the key is not stored in external hardware, we have to - * load the private key. Try first with empty passphrase; if it - * fails, ask for a passphrase. - */ - if (public->flags & KEY_FLAG_EXT) - private = public; - else - private = key_load_private_type(KEY_RSA1, authfile, "", NULL, - &perm_ok); - if (private == NULL && !options.batch_mode && perm_ok) { - snprintf(buf, sizeof(buf), - "Enter passphrase for RSA key '%.100s': ", comment); - for (i = 0; i < options.number_of_password_prompts; i++) { - passphrase = read_passphrase(buf, 0); - if (strcmp(passphrase, "") != 0) { - private = key_load_private_type(KEY_RSA1, - authfile, passphrase, NULL, NULL); - quit = 0; - } else { - debug2("no passphrase given, try next key"); - quit = 1; - } - memset(passphrase, 0, strlen(passphrase)); - xfree(passphrase); - if (private != NULL || quit) - break; - debug2("bad passphrase given, try again..."); - } - } - /* We no longer need the comment. */ - xfree(comment); - - if (private == NULL) { - if (!options.batch_mode && perm_ok) - error("Bad passphrase."); - - /* Send a dummy response packet to avoid protocol error. */ - packet_start(SSH_CMSG_AUTH_RSA_RESPONSE); - for (i = 0; i < 16; i++) - packet_put_char(0); - packet_send(); - packet_write_wait(); - - /* Expect the server to reject it... */ - packet_read_expect(SSH_SMSG_FAILURE); - BN_clear_free(challenge); - return 0; - } - - /* Compute and send a response to the challenge. */ - respond_to_rsa_challenge(challenge, private->rsa); - - /* Destroy the private key unless it in external hardware. */ - if (!(private->flags & KEY_FLAG_EXT)) - key_free(private); - - /* We no longer need the challenge. */ - BN_clear_free(challenge); - - /* Wait for response from the server. */ - type = packet_read(); - if (type == SSH_SMSG_SUCCESS) { - debug("RSA authentication accepted by server."); - return 1; - } - if (type != SSH_SMSG_FAILURE) - packet_disconnect("Protocol error waiting RSA auth response: %d", type); - debug("RSA authentication refused."); - return 0; -} - -/* - * Tries to authenticate the user using combined rhosts or /etc/hosts.equiv - * authentication and RSA host authentication. - */ -static int -try_rhosts_rsa_authentication(const char *local_user, Key * host_key) -{ - int type; - BIGNUM *challenge; - - debug("Trying rhosts or /etc/hosts.equiv with RSA host authentication."); - - /* Tell the server that we are willing to authenticate using this key. */ - packet_start(SSH_CMSG_AUTH_RHOSTS_RSA); - packet_put_cstring(local_user); - packet_put_int(BN_num_bits(host_key->rsa->n)); - packet_put_bignum(host_key->rsa->e); - packet_put_bignum(host_key->rsa->n); - packet_send(); - packet_write_wait(); - - /* Wait for server's response. */ - type = packet_read(); - - /* The server responds with failure if it doesn't admit our - .rhosts authentication or doesn't know our host key. */ - if (type == SSH_SMSG_FAILURE) { - debug("Server refused our rhosts authentication or host key."); - return 0; - } - /* Otherwise, the server should respond with a challenge. */ - if (type != SSH_SMSG_AUTH_RSA_CHALLENGE) - packet_disconnect("Protocol error during RSA authentication: %d", type); - - /* Get the challenge from the packet. */ - if ((challenge = BN_new()) == NULL) - fatal("try_rhosts_rsa_authentication: BN_new failed"); - packet_get_bignum(challenge); - packet_check_eom(); - - debug("Received RSA challenge for host key from server."); - - /* Compute a response to the challenge. */ - respond_to_rsa_challenge(challenge, host_key->rsa); - - /* We no longer need the challenge. */ - BN_clear_free(challenge); - - /* Wait for response from the server. */ - type = packet_read(); - if (type == SSH_SMSG_SUCCESS) { - debug("Rhosts or /etc/hosts.equiv with RSA host authentication accepted by server."); - return 1; - } - if (type != SSH_SMSG_FAILURE) - packet_disconnect("Protocol error waiting RSA auth response: %d", type); - debug("Rhosts or /etc/hosts.equiv with RSA host authentication refused."); - return 0; -} - -/* - * Tries to authenticate with any string-based challenge/response system. - * Note that the client code is not tied to s/key or TIS. - */ -static int -try_challenge_response_authentication(void) -{ - int type, i; - u_int clen; - char prompt[1024]; - char *challenge, *response; - - debug("Doing challenge response authentication."); - - for (i = 0; i < options.number_of_password_prompts; i++) { - /* request a challenge */ - packet_start(SSH_CMSG_AUTH_TIS); - packet_send(); - packet_write_wait(); - - type = packet_read(); - if (type != SSH_SMSG_FAILURE && - type != SSH_SMSG_AUTH_TIS_CHALLENGE) { - packet_disconnect("Protocol error: got %d in response " - "to SSH_CMSG_AUTH_TIS", type); - } - if (type != SSH_SMSG_AUTH_TIS_CHALLENGE) { - debug("No challenge."); - return 0; - } - challenge = packet_get_string(&clen); - packet_check_eom(); - snprintf(prompt, sizeof prompt, "%s%s", challenge, - strchr(challenge, '\n') ? "" : "\nResponse: "); - xfree(challenge); - if (i != 0) - error("Permission denied, please try again."); - if (options.cipher == SSH_CIPHER_NONE) - logit("WARNING: Encryption is disabled! " - "Response will be transmitted in clear text."); - response = read_passphrase(prompt, 0); - if (strcmp(response, "") == 0) { - xfree(response); - break; - } - packet_start(SSH_CMSG_AUTH_TIS_RESPONSE); - ssh_put_password(response); - memset(response, 0, strlen(response)); - xfree(response); - packet_send(); - packet_write_wait(); - type = packet_read(); - if (type == SSH_SMSG_SUCCESS) - return 1; - if (type != SSH_SMSG_FAILURE) - packet_disconnect("Protocol error: got %d in response " - "to SSH_CMSG_AUTH_TIS_RESPONSE", type); - } - /* failure */ - return 0; -} - -/* - * Tries to authenticate with plain passwd authentication. - */ -static int -try_password_authentication(char *prompt) -{ - int type, i; - char *password; - - debug("Doing password authentication."); - if (options.cipher == SSH_CIPHER_NONE) - logit("WARNING: Encryption is disabled! Password will be transmitted in clear text."); - for (i = 0; i < options.number_of_password_prompts; i++) { - if (i != 0) - error("Permission denied, please try again."); - password = read_passphrase(prompt, 0); - packet_start(SSH_CMSG_AUTH_PASSWORD); - ssh_put_password(password); - memset(password, 0, strlen(password)); - xfree(password); - packet_send(); - packet_write_wait(); - - type = packet_read(); - if (type == SSH_SMSG_SUCCESS) - return 1; - if (type != SSH_SMSG_FAILURE) - packet_disconnect("Protocol error: got %d in response to passwd auth", type); - } - /* failure */ - return 0; -} - -/* - * SSH1 key exchange - */ -void -ssh_kex(char *host, struct sockaddr *hostaddr) -{ - int i; - BIGNUM *key; - Key *host_key, *server_key; - int bits, rbits; - int ssh_cipher_default = SSH_CIPHER_3DES; - u_char session_key[SSH_SESSION_KEY_LENGTH]; - u_char cookie[8]; - u_int supported_ciphers; - u_int server_flags, client_flags; - u_int32_t rnd = 0; - - debug("Waiting for server public key."); - - /* Wait for a public key packet from the server. */ - packet_read_expect(SSH_SMSG_PUBLIC_KEY); - - /* Get cookie from the packet. */ - for (i = 0; i < 8; i++) - cookie[i] = packet_get_char(); - - /* Get the public key. */ - server_key = key_new(KEY_RSA1); - bits = packet_get_int(); - packet_get_bignum(server_key->rsa->e); - packet_get_bignum(server_key->rsa->n); - - rbits = BN_num_bits(server_key->rsa->n); - if (bits != rbits) { - logit("Warning: Server lies about size of server public key: " - "actual size is %d bits vs. announced %d.", rbits, bits); - logit("Warning: This may be due to an old implementation of ssh."); - } - /* Get the host key. */ - host_key = key_new(KEY_RSA1); - bits = packet_get_int(); - packet_get_bignum(host_key->rsa->e); - packet_get_bignum(host_key->rsa->n); - - rbits = BN_num_bits(host_key->rsa->n); - if (bits != rbits) { - logit("Warning: Server lies about size of server host key: " - "actual size is %d bits vs. announced %d.", rbits, bits); - logit("Warning: This may be due to an old implementation of ssh."); - } - - /* Get protocol flags. */ - server_flags = packet_get_int(); - packet_set_protocol_flags(server_flags); - - supported_ciphers = packet_get_int(); - supported_authentications = packet_get_int(); - packet_check_eom(); - - debug("Received server public key (%d bits) and host key (%d bits).", - BN_num_bits(server_key->rsa->n), BN_num_bits(host_key->rsa->n)); - - if (verify_host_key(host, hostaddr, host_key) == -1) - fatal("Host key verification failed."); - - client_flags = SSH_PROTOFLAG_SCREEN_NUMBER | SSH_PROTOFLAG_HOST_IN_FWD_OPEN; - - derive_ssh1_session_id(host_key->rsa->n, server_key->rsa->n, cookie, session_id); - - /* Generate a session key. */ - arc4random_stir(); - - /* - * Generate an encryption key for the session. The key is a 256 bit - * random number, interpreted as a 32-byte key, with the least - * significant 8 bits being the first byte of the key. - */ - for (i = 0; i < 32; i++) { - if (i % 4 == 0) - rnd = arc4random(); - session_key[i] = rnd & 0xff; - rnd >>= 8; - } - - /* - * According to the protocol spec, the first byte of the session key - * is the highest byte of the integer. The session key is xored with - * the first 16 bytes of the session id. - */ - if ((key = BN_new()) == NULL) - fatal("ssh_kex: BN_new failed"); - if (BN_set_word(key, 0) == 0) - fatal("ssh_kex: BN_set_word failed"); - for (i = 0; i < SSH_SESSION_KEY_LENGTH; i++) { - if (BN_lshift(key, key, 8) == 0) - fatal("ssh_kex: BN_lshift failed"); - if (i < 16) { - if (BN_add_word(key, session_key[i] ^ session_id[i]) - == 0) - fatal("ssh_kex: BN_add_word failed"); - } else { - if (BN_add_word(key, session_key[i]) == 0) - fatal("ssh_kex: BN_add_word failed"); - } - } - - /* - * Encrypt the integer using the public key and host key of the - * server (key with smaller modulus first). - */ - if (BN_cmp(server_key->rsa->n, host_key->rsa->n) < 0) { - /* Public key has smaller modulus. */ - if (BN_num_bits(host_key->rsa->n) < - BN_num_bits(server_key->rsa->n) + SSH_KEY_BITS_RESERVED) { - fatal("respond_to_rsa_challenge: host_key %d < server_key %d + " - "SSH_KEY_BITS_RESERVED %d", - BN_num_bits(host_key->rsa->n), - BN_num_bits(server_key->rsa->n), - SSH_KEY_BITS_RESERVED); - } - rsa_public_encrypt(key, key, server_key->rsa); - rsa_public_encrypt(key, key, host_key->rsa); - } else { - /* Host key has smaller modulus (or they are equal). */ - if (BN_num_bits(server_key->rsa->n) < - BN_num_bits(host_key->rsa->n) + SSH_KEY_BITS_RESERVED) { - fatal("respond_to_rsa_challenge: server_key %d < host_key %d + " - "SSH_KEY_BITS_RESERVED %d", - BN_num_bits(server_key->rsa->n), - BN_num_bits(host_key->rsa->n), - SSH_KEY_BITS_RESERVED); - } - rsa_public_encrypt(key, key, host_key->rsa); - rsa_public_encrypt(key, key, server_key->rsa); - } - - /* Destroy the public keys since we no longer need them. */ - key_free(server_key); - key_free(host_key); - - if (options.cipher == SSH_CIPHER_NOT_SET) { - if (cipher_mask_ssh1(1) & supported_ciphers & (1 << ssh_cipher_default)) - options.cipher = ssh_cipher_default; - } else if (options.cipher == SSH_CIPHER_INVALID || - !(cipher_mask_ssh1(1) & (1 << options.cipher))) { - logit("No valid SSH1 cipher, using %.100s instead.", - cipher_name(ssh_cipher_default)); - options.cipher = ssh_cipher_default; - } - /* Check that the selected cipher is supported. */ - if (!(supported_ciphers & (1 << options.cipher))) - fatal("Selected cipher type %.100s not supported by server.", - cipher_name(options.cipher)); - - debug("Encryption type: %.100s", cipher_name(options.cipher)); - - /* Send the encrypted session key to the server. */ - packet_start(SSH_CMSG_SESSION_KEY); - packet_put_char(options.cipher); - - /* Send the cookie back to the server. */ - for (i = 0; i < 8; i++) - packet_put_char(cookie[i]); - - /* Send and destroy the encrypted encryption key integer. */ - packet_put_bignum(key); - BN_clear_free(key); - - /* Send protocol flags. */ - packet_put_int(client_flags); - - /* Send the packet now. */ - packet_send(); - packet_write_wait(); - - debug("Sent encrypted session key."); - - /* Set the encryption key. */ - packet_set_encryption_key(session_key, SSH_SESSION_KEY_LENGTH, options.cipher); - - /* We will no longer need the session key here. Destroy any extra copies. */ - memset(session_key, 0, sizeof(session_key)); - - /* - * Expect a success message from the server. Note that this message - * will be received in encrypted form. - */ - packet_read_expect(SSH_SMSG_SUCCESS); - - debug("Received encrypted confirmation."); -} - -/* - * Authenticate user - */ -void -ssh_userauth1(const char *local_user, const char *server_user, char *host, - Sensitive *sensitive) -{ - int i, type; - - if (supported_authentications == 0) - fatal("ssh_userauth1: server supports no auth methods"); - - /* Send the name of the user to log in as on the server. */ - packet_start(SSH_CMSG_USER); - packet_put_cstring(server_user); - packet_send(); - packet_write_wait(); - - /* - * The server should respond with success if no authentication is - * needed (the user has no password). Otherwise the server responds - * with failure. - */ - type = packet_read(); - - /* check whether the connection was accepted without authentication. */ - if (type == SSH_SMSG_SUCCESS) - goto success; - if (type != SSH_SMSG_FAILURE) - packet_disconnect("Protocol error: got %d in response to SSH_CMSG_USER", type); - - /* - * Try .rhosts or /etc/hosts.equiv authentication with RSA host - * authentication. - */ - if ((supported_authentications & (1 << SSH_AUTH_RHOSTS_RSA)) && - options.rhosts_rsa_authentication) { - for (i = 0; i < sensitive->nkeys; i++) { - if (sensitive->keys[i] != NULL && - sensitive->keys[i]->type == KEY_RSA1 && - try_rhosts_rsa_authentication(local_user, - sensitive->keys[i])) - goto success; - } - } - /* Try RSA authentication if the server supports it. */ - if ((supported_authentications & (1 << SSH_AUTH_RSA)) && - options.rsa_authentication) { - /* - * Try RSA authentication using the authentication agent. The - * agent is tried first because no passphrase is needed for - * it, whereas identity files may require passphrases. - */ - if (try_agent_authentication()) - goto success; - - /* Try RSA authentication for each identity. */ - for (i = 0; i < options.num_identity_files; i++) - if (options.identity_keys[i] != NULL && - options.identity_keys[i]->type == KEY_RSA1 && - try_rsa_authentication(i)) - goto success; - } - /* Try challenge response authentication if the server supports it. */ - if ((supported_authentications & (1 << SSH_AUTH_TIS)) && - options.challenge_response_authentication && !options.batch_mode) { - if (try_challenge_response_authentication()) - goto success; - } - /* Try password authentication if the server supports it. */ - if ((supported_authentications & (1 << SSH_AUTH_PASSWORD)) && - options.password_authentication && !options.batch_mode) { - char prompt[80]; - - snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password: ", - server_user, host); - if (try_password_authentication(prompt)) - goto success; - } - /* All authentication methods have failed. Exit with an error message. */ - fatal("Permission denied."); - /* NOTREACHED */ - - success: - return; /* need statement after label */ -} |