f30cce5c6c
It seems as if uninitialised memory was the culprit. We may want to contribute this back to the OpenSSH project. Submitted by: Alexander Leidinger <Alexander@Leidinger.net> on -current.
581 lines
14 KiB
C
581 lines
14 KiB
C
/*
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*
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* authfd.c
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*
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* Author: Tatu Ylonen <ylo@cs.hut.fi>
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*
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* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
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* All rights reserved
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*
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* Created: Wed Mar 29 01:30:28 1995 ylo
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*
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* Functions for connecting the local authentication agent.
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*
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* $FreeBSD$
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*/
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#include "includes.h"
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RCSID("$Id: authfd.c,v 1.19 2000/04/29 18:11:52 markus Exp $");
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#include "ssh.h"
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#include "rsa.h"
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#include "authfd.h"
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#include "buffer.h"
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#include "bufaux.h"
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#include "xmalloc.h"
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#include "getput.h"
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#include <openssl/rsa.h>
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/* Returns the number of the authentication fd, or -1 if there is none. */
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int
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ssh_get_authentication_socket()
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{
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const char *authsocket;
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int sock, len;
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struct sockaddr_un sunaddr;
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authsocket = getenv(SSH_AUTHSOCKET_ENV_NAME);
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if (!authsocket)
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return -1;
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sunaddr.sun_family = AF_UNIX;
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strlcpy(sunaddr.sun_path, authsocket, sizeof(sunaddr.sun_path));
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sunaddr.sun_len = len = SUN_LEN(&sunaddr)+1;
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sock = socket(AF_UNIX, SOCK_STREAM, 0);
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if (sock < 0)
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return -1;
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/* close on exec */
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if (fcntl(sock, F_SETFD, 1) == -1) {
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close(sock);
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return -1;
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}
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if (connect(sock, (struct sockaddr *) & sunaddr, len) < 0) {
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close(sock);
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return -1;
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}
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return sock;
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}
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/*
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* Closes the agent socket if it should be closed (depends on how it was
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* obtained). The argument must have been returned by
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* ssh_get_authentication_socket().
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*/
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void
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ssh_close_authentication_socket(int sock)
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{
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if (getenv(SSH_AUTHSOCKET_ENV_NAME))
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close(sock);
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}
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/*
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* Opens and connects a private socket for communication with the
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* authentication agent. Returns the file descriptor (which must be
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* shut down and closed by the caller when no longer needed).
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* Returns NULL if an error occurred and the connection could not be
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* opened.
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*/
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AuthenticationConnection *
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ssh_get_authentication_connection()
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{
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AuthenticationConnection *auth;
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int sock;
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sock = ssh_get_authentication_socket();
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/*
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* Fail if we couldn't obtain a connection. This happens if we
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* exited due to a timeout.
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*/
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if (sock < 0)
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return NULL;
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auth = xmalloc(sizeof(*auth));
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auth->fd = sock;
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buffer_init(&auth->packet);
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buffer_init(&auth->identities);
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auth->howmany = 0;
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return auth;
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}
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/*
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* Closes the connection to the authentication agent and frees any associated
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* memory.
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*/
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void
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ssh_close_authentication_connection(AuthenticationConnection *ac)
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{
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buffer_free(&ac->packet);
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buffer_free(&ac->identities);
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close(ac->fd);
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xfree(ac);
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}
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/*
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* Returns the first authentication identity held by the agent.
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* Returns true if an identity is available, 0 otherwise.
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* The caller must initialize the integers before the call, and free the
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* comment after a successful call (before calling ssh_get_next_identity).
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*/
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int
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ssh_get_first_identity(AuthenticationConnection *auth,
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BIGNUM *e, BIGNUM *n, char **comment)
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{
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unsigned char msg[8192];
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int len, l;
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/*
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* Send a message to the agent requesting for a list of the
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* identities it can represent.
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*/
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msg[0] = 0;
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msg[1] = 0;
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msg[2] = 0;
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msg[3] = 1;
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msg[4] = SSH_AGENTC_REQUEST_RSA_IDENTITIES;
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if (atomicio(write, auth->fd, msg, 5) != 5) {
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error("write auth->fd: %.100s", strerror(errno));
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return 0;
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}
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/* Read the length of the response. XXX implement timeouts here. */
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len = 4;
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while (len > 0) {
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l = read(auth->fd, msg + 4 - len, len);
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if (l <= 0) {
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error("read auth->fd: %.100s", strerror(errno));
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return 0;
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}
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len -= l;
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}
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/*
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* Extract the length, and check it for sanity. (We cannot trust
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* authentication agents).
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*/
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len = GET_32BIT(msg);
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if (len < 1 || len > 256 * 1024)
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fatal("Authentication reply message too long: %d\n", len);
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/* Read the packet itself. */
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buffer_clear(&auth->identities);
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while (len > 0) {
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l = len;
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if (l > sizeof(msg))
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l = sizeof(msg);
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l = read(auth->fd, msg, l);
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if (l <= 0)
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fatal("Incomplete authentication reply.");
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buffer_append(&auth->identities, (char *) msg, l);
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len -= l;
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}
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/* Get message type, and verify that we got a proper answer. */
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buffer_get(&auth->identities, (char *) msg, 1);
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if (msg[0] != SSH_AGENT_RSA_IDENTITIES_ANSWER)
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fatal("Bad authentication reply message type: %d", msg[0]);
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/* Get the number of entries in the response and check it for sanity. */
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auth->howmany = buffer_get_int(&auth->identities);
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if (auth->howmany > 1024)
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fatal("Too many identities in authentication reply: %d\n", auth->howmany);
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/* Return the first entry (if any). */
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return ssh_get_next_identity(auth, e, n, comment);
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}
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/*
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* Returns the next authentication identity for the agent. Other functions
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* can be called between this and ssh_get_first_identity or two calls of this
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* function. This returns 0 if there are no more identities. The caller
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* must free comment after a successful return.
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*/
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int
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ssh_get_next_identity(AuthenticationConnection *auth,
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BIGNUM *e, BIGNUM *n, char **comment)
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{
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unsigned int bits;
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/* Return failure if no more entries. */
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if (auth->howmany <= 0)
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return 0;
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/*
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* Get the next entry from the packet. These will abort with a fatal
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* error if the packet is too short or contains corrupt data.
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*/
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bits = buffer_get_int(&auth->identities);
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buffer_get_bignum(&auth->identities, e);
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buffer_get_bignum(&auth->identities, n);
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*comment = buffer_get_string(&auth->identities, NULL);
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if (bits != BN_num_bits(n))
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log("Warning: identity keysize mismatch: actual %d, announced %u",
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BN_num_bits(n), bits);
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/* Decrement the number of remaining entries. */
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auth->howmany--;
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return 1;
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}
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/*
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* Generates a random challenge, sends it to the agent, and waits for
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* response from the agent. Returns true (non-zero) if the agent gave the
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* correct answer, zero otherwise. Response type selects the style of
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* response desired, with 0 corresponding to protocol version 1.0 (no longer
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* supported) and 1 corresponding to protocol version 1.1.
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*/
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int
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ssh_decrypt_challenge(AuthenticationConnection *auth,
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BIGNUM* e, BIGNUM *n, BIGNUM *challenge,
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unsigned char session_id[16],
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unsigned int response_type,
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unsigned char response[16])
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{
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Buffer buffer;
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unsigned char buf[8192];
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int len, l, i;
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/* Response type 0 is no longer supported. */
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if (response_type == 0)
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fatal("Compatibility with ssh protocol version 1.0 no longer supported.");
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/* Format a message to the agent. */
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buf[0] = SSH_AGENTC_RSA_CHALLENGE;
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buffer_init(&buffer);
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buffer_append(&buffer, (char *) buf, 1);
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buffer_put_int(&buffer, BN_num_bits(n));
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buffer_put_bignum(&buffer, e);
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buffer_put_bignum(&buffer, n);
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buffer_put_bignum(&buffer, challenge);
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buffer_append(&buffer, (char *) session_id, 16);
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buffer_put_int(&buffer, response_type);
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/* Get the length of the message, and format it in the buffer. */
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len = buffer_len(&buffer);
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PUT_32BIT(buf, len);
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/* Send the length and then the packet to the agent. */
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if (atomicio(write, auth->fd, buf, 4) != 4 ||
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atomicio(write, auth->fd, buffer_ptr(&buffer),
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buffer_len(&buffer)) != buffer_len(&buffer)) {
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error("Error writing to authentication socket.");
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error_cleanup:
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buffer_free(&buffer);
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return 0;
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}
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/*
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* Wait for response from the agent. First read the length of the
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* response packet.
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*/
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len = 4;
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while (len > 0) {
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l = read(auth->fd, buf + 4 - len, len);
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if (l <= 0) {
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error("Error reading response length from authentication socket.");
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goto error_cleanup;
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}
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len -= l;
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}
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/* Extract the length, and check it for sanity. */
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len = GET_32BIT(buf);
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if (len > 256 * 1024)
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fatal("Authentication response too long: %d", len);
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/* Read the rest of the response in tothe buffer. */
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buffer_clear(&buffer);
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while (len > 0) {
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l = len;
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if (l > sizeof(buf))
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l = sizeof(buf);
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l = read(auth->fd, buf, l);
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if (l <= 0) {
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error("Error reading response from authentication socket.");
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goto error_cleanup;
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}
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buffer_append(&buffer, (char *) buf, l);
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len -= l;
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}
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/* Get the type of the packet. */
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buffer_get(&buffer, (char *) buf, 1);
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/* Check for agent failure message. */
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if (buf[0] == SSH_AGENT_FAILURE) {
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log("Agent admitted failure to authenticate using the key.");
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goto error_cleanup;
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}
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/* Now it must be an authentication response packet. */
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if (buf[0] != SSH_AGENT_RSA_RESPONSE)
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fatal("Bad authentication response: %d", buf[0]);
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/*
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* Get the response from the packet. This will abort with a fatal
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* error if the packet is corrupt.
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*/
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for (i = 0; i < 16; i++)
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response[i] = buffer_get_char(&buffer);
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/* The buffer containing the packet is no longer needed. */
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buffer_free(&buffer);
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/* Correct answer. */
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return 1;
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}
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/*
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* Adds an identity to the authentication server. This call is not meant to
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* be used by normal applications.
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*/
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int
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ssh_add_identity(AuthenticationConnection *auth,
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RSA * key, const char *comment)
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{
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Buffer buffer;
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unsigned char buf[8192];
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int len, l, type;
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/* Format a message to the agent. */
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buffer_init(&buffer);
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buffer_put_char(&buffer, SSH_AGENTC_ADD_RSA_IDENTITY);
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buffer_put_int(&buffer, BN_num_bits(key->n));
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buffer_put_bignum(&buffer, key->n);
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buffer_put_bignum(&buffer, key->e);
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buffer_put_bignum(&buffer, key->d);
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/* To keep within the protocol: p < q for ssh. in SSL p > q */
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buffer_put_bignum(&buffer, key->iqmp); /* ssh key->u */
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buffer_put_bignum(&buffer, key->q); /* ssh key->p, SSL key->q */
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buffer_put_bignum(&buffer, key->p); /* ssh key->q, SSL key->p */
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buffer_put_string(&buffer, comment, strlen(comment));
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/* Get the length of the message, and format it in the buffer. */
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len = buffer_len(&buffer);
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PUT_32BIT(buf, len);
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/* Send the length and then the packet to the agent. */
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if (atomicio(write, auth->fd, buf, 4) != 4 ||
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atomicio(write, auth->fd, buffer_ptr(&buffer),
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buffer_len(&buffer)) != buffer_len(&buffer)) {
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error("Error writing to authentication socket.");
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error_cleanup:
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buffer_free(&buffer);
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return 0;
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}
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/* Wait for response from the agent. First read the length of the
|
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response packet. */
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len = 4;
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while (len > 0) {
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l = read(auth->fd, buf + 4 - len, len);
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if (l <= 0) {
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error("Error reading response length from authentication socket.");
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goto error_cleanup;
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}
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len -= l;
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}
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/* Extract the length, and check it for sanity. */
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len = GET_32BIT(buf);
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if (len > 256 * 1024)
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fatal("Add identity response too long: %d", len);
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/* Read the rest of the response in tothe buffer. */
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buffer_clear(&buffer);
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while (len > 0) {
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l = len;
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if (l > sizeof(buf))
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l = sizeof(buf);
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l = read(auth->fd, buf, l);
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if (l <= 0) {
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error("Error reading response from authentication socket.");
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goto error_cleanup;
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}
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buffer_append(&buffer, (char *) buf, l);
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len -= l;
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}
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|
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/* Get the type of the packet. */
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type = buffer_get_char(&buffer);
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switch (type) {
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case SSH_AGENT_FAILURE:
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buffer_free(&buffer);
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return 0;
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case SSH_AGENT_SUCCESS:
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buffer_free(&buffer);
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return 1;
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default:
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fatal("Bad response to add identity from authentication agent: %d",
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type);
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}
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/* NOTREACHED */
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return 0;
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}
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|
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/*
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* Removes an identity from the authentication server. This call is not
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* meant to be used by normal applications.
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*/
|
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|
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int
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ssh_remove_identity(AuthenticationConnection *auth, RSA *key)
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{
|
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Buffer buffer;
|
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unsigned char buf[8192];
|
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int len, l, type;
|
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|
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/* Format a message to the agent. */
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buffer_init(&buffer);
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buffer_put_char(&buffer, SSH_AGENTC_REMOVE_RSA_IDENTITY);
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buffer_put_int(&buffer, BN_num_bits(key->n));
|
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buffer_put_bignum(&buffer, key->e);
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buffer_put_bignum(&buffer, key->n);
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|
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/* Get the length of the message, and format it in the buffer. */
|
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len = buffer_len(&buffer);
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PUT_32BIT(buf, len);
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|
|
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/* Send the length and then the packet to the agent. */
|
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if (atomicio(write, auth->fd, buf, 4) != 4 ||
|
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atomicio(write, auth->fd, buffer_ptr(&buffer),
|
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buffer_len(&buffer)) != buffer_len(&buffer)) {
|
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error("Error writing to authentication socket.");
|
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error_cleanup:
|
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buffer_free(&buffer);
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return 0;
|
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}
|
|
/*
|
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* Wait for response from the agent. First read the length of the
|
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* response packet.
|
|
*/
|
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len = 4;
|
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while (len > 0) {
|
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l = read(auth->fd, buf + 4 - len, len);
|
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if (l <= 0) {
|
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error("Error reading response length from authentication socket.");
|
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goto error_cleanup;
|
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}
|
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len -= l;
|
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}
|
|
|
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/* Extract the length, and check it for sanity. */
|
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len = GET_32BIT(buf);
|
|
if (len > 256 * 1024)
|
|
fatal("Remove identity response too long: %d", len);
|
|
|
|
/* Read the rest of the response in tothe buffer. */
|
|
buffer_clear(&buffer);
|
|
while (len > 0) {
|
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l = len;
|
|
if (l > sizeof(buf))
|
|
l = sizeof(buf);
|
|
l = read(auth->fd, buf, l);
|
|
if (l <= 0) {
|
|
error("Error reading response from authentication socket.");
|
|
goto error_cleanup;
|
|
}
|
|
buffer_append(&buffer, (char *) buf, l);
|
|
len -= l;
|
|
}
|
|
|
|
/* Get the type of the packet. */
|
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type = buffer_get_char(&buffer);
|
|
switch (type) {
|
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case SSH_AGENT_FAILURE:
|
|
buffer_free(&buffer);
|
|
return 0;
|
|
case SSH_AGENT_SUCCESS:
|
|
buffer_free(&buffer);
|
|
return 1;
|
|
default:
|
|
fatal("Bad response to remove identity from authentication agent: %d",
|
|
type);
|
|
}
|
|
/* NOTREACHED */
|
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return 0;
|
|
}
|
|
|
|
/*
|
|
* Removes all identities from the agent. This call is not meant to be used
|
|
* by normal applications.
|
|
*/
|
|
|
|
int
|
|
ssh_remove_all_identities(AuthenticationConnection *auth)
|
|
{
|
|
Buffer buffer;
|
|
unsigned char buf[8192];
|
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int len, l, type;
|
|
|
|
/* Get the length of the message, and format it in the buffer. */
|
|
PUT_32BIT(buf, 1);
|
|
buf[4] = SSH_AGENTC_REMOVE_ALL_RSA_IDENTITIES;
|
|
|
|
/* Send the length and then the packet to the agent. */
|
|
if (atomicio(write, auth->fd, buf, 5) != 5) {
|
|
error("Error writing to authentication socket.");
|
|
return 0;
|
|
}
|
|
/*
|
|
* Wait for response from the agent. First read the length of the
|
|
* response packet.
|
|
*/
|
|
len = 4;
|
|
while (len > 0) {
|
|
l = read(auth->fd, buf + 4 - len, len);
|
|
if (l <= 0) {
|
|
error("Error reading response length from authentication socket.");
|
|
return 0;
|
|
}
|
|
len -= l;
|
|
}
|
|
|
|
/* Extract the length, and check it for sanity. */
|
|
len = GET_32BIT(buf);
|
|
if (len > 256 * 1024)
|
|
fatal("Remove identity response too long: %d", len);
|
|
|
|
/* Read the rest of the response into the buffer. */
|
|
buffer_init(&buffer);
|
|
while (len > 0) {
|
|
l = len;
|
|
if (l > sizeof(buf))
|
|
l = sizeof(buf);
|
|
l = read(auth->fd, buf, l);
|
|
if (l <= 0) {
|
|
error("Error reading response from authentication socket.");
|
|
buffer_free(&buffer);
|
|
return 0;
|
|
}
|
|
buffer_append(&buffer, (char *) buf, l);
|
|
len -= l;
|
|
}
|
|
|
|
/* Get the type of the packet. */
|
|
type = buffer_get_char(&buffer);
|
|
switch (type) {
|
|
case SSH_AGENT_FAILURE:
|
|
buffer_free(&buffer);
|
|
return 0;
|
|
case SSH_AGENT_SUCCESS:
|
|
buffer_free(&buffer);
|
|
return 1;
|
|
default:
|
|
fatal("Bad response to remove identity from authentication agent: %d",
|
|
type);
|
|
}
|
|
/* NOTREACHED */
|
|
return 0;
|
|
}
|