| /* |
| * |
| * authfd.c |
| * |
| * Author: Tatu Ylonen <ylo@cs.hut.fi> |
| * |
| * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland |
| * All rights reserved |
| * |
| * Created: Wed Mar 29 01:30:28 1995 ylo |
| * |
| * Functions for connecting the local authentication agent. |
| * |
| */ |
| |
| #include "includes.h" |
| RCSID("$Id: authfd.c,v 1.12 2000/04/16 01:18:40 damien Exp $"); |
| |
| #include "ssh.h" |
| #include "rsa.h" |
| #include "authfd.h" |
| #include "buffer.h" |
| #include "bufaux.h" |
| #include "xmalloc.h" |
| #include "getput.h" |
| |
| #ifdef HAVE_OPENSSL |
| #include <openssl/rsa.h> |
| #endif |
| #ifdef HAVE_SSL |
| #include <ssl/rsa.h> |
| #endif |
| |
| /* Returns the number of the authentication fd, or -1 if there is none. */ |
| |
| int |
| ssh_get_authentication_socket() |
| { |
| const char *authsocket; |
| int sock; |
| struct sockaddr_un sunaddr; |
| |
| authsocket = getenv(SSH_AUTHSOCKET_ENV_NAME); |
| if (!authsocket) |
| return -1; |
| |
| sunaddr.sun_family = AF_UNIX; |
| strlcpy(sunaddr.sun_path, authsocket, sizeof(sunaddr.sun_path)); |
| |
| sock = socket(AF_UNIX, SOCK_STREAM, 0); |
| if (sock < 0) |
| return -1; |
| |
| /* close on exec */ |
| if (fcntl(sock, F_SETFD, 1) == -1) { |
| close(sock); |
| return -1; |
| } |
| if (connect(sock, (struct sockaddr *) & sunaddr, sizeof(sunaddr)) < 0) { |
| close(sock); |
| return -1; |
| } |
| return sock; |
| } |
| |
| /* |
| * Closes the agent socket if it should be closed (depends on how it was |
| * obtained). The argument must have been returned by |
| * ssh_get_authentication_socket(). |
| */ |
| |
| void |
| ssh_close_authentication_socket(int sock) |
| { |
| if (getenv(SSH_AUTHSOCKET_ENV_NAME)) |
| close(sock); |
| } |
| |
| /* |
| * Opens and connects a private socket for communication with the |
| * authentication agent. Returns the file descriptor (which must be |
| * shut down and closed by the caller when no longer needed). |
| * Returns NULL if an error occurred and the connection could not be |
| * opened. |
| */ |
| |
| AuthenticationConnection * |
| ssh_get_authentication_connection() |
| { |
| AuthenticationConnection *auth; |
| int sock; |
| |
| sock = ssh_get_authentication_socket(); |
| |
| /* |
| * Fail if we couldn't obtain a connection. This happens if we |
| * exited due to a timeout. |
| */ |
| if (sock < 0) |
| return NULL; |
| |
| auth = xmalloc(sizeof(*auth)); |
| auth->fd = sock; |
| buffer_init(&auth->packet); |
| buffer_init(&auth->identities); |
| auth->howmany = 0; |
| |
| return auth; |
| } |
| |
| /* |
| * Closes the connection to the authentication agent and frees any associated |
| * memory. |
| */ |
| |
| void |
| ssh_close_authentication_connection(AuthenticationConnection *ac) |
| { |
| buffer_free(&ac->packet); |
| buffer_free(&ac->identities); |
| close(ac->fd); |
| xfree(ac); |
| } |
| |
| /* |
| * Returns the first authentication identity held by the agent. |
| * Returns true if an identity is available, 0 otherwise. |
| * The caller must initialize the integers before the call, and free the |
| * comment after a successful call (before calling ssh_get_next_identity). |
| */ |
| |
| int |
| ssh_get_first_identity(AuthenticationConnection *auth, |
| BIGNUM *e, BIGNUM *n, char **comment) |
| { |
| unsigned char msg[8192]; |
| int len, l; |
| |
| /* |
| * Send a message to the agent requesting for a list of the |
| * identities it can represent. |
| */ |
| msg[0] = 0; |
| msg[1] = 0; |
| msg[2] = 0; |
| msg[3] = 1; |
| msg[4] = SSH_AGENTC_REQUEST_RSA_IDENTITIES; |
| if (atomicio(write, auth->fd, msg, 5) != 5) { |
| error("write auth->fd: %.100s", strerror(errno)); |
| return 0; |
| } |
| /* Read the length of the response. XXX implement timeouts here. */ |
| len = 4; |
| while (len > 0) { |
| l = read(auth->fd, msg + 4 - len, len); |
| if (l <= 0) { |
| error("read auth->fd: %.100s", strerror(errno)); |
| return 0; |
| } |
| len -= l; |
| } |
| |
| /* |
| * Extract the length, and check it for sanity. (We cannot trust |
| * authentication agents). |
| */ |
| len = GET_32BIT(msg); |
| if (len < 1 || len > 256 * 1024) |
| fatal("Authentication reply message too long: %d\n", len); |
| |
| /* Read the packet itself. */ |
| buffer_clear(&auth->identities); |
| while (len > 0) { |
| l = len; |
| if (l > sizeof(msg)) |
| l = sizeof(msg); |
| l = read(auth->fd, msg, l); |
| if (l <= 0) |
| fatal("Incomplete authentication reply."); |
| buffer_append(&auth->identities, (char *) msg, l); |
| len -= l; |
| } |
| |
| /* Get message type, and verify that we got a proper answer. */ |
| buffer_get(&auth->identities, (char *) msg, 1); |
| if (msg[0] != SSH_AGENT_RSA_IDENTITIES_ANSWER) |
| fatal("Bad authentication reply message type: %d", msg[0]); |
| |
| /* Get the number of entries in the response and check it for sanity. */ |
| auth->howmany = buffer_get_int(&auth->identities); |
| if (auth->howmany > 1024) |
| fatal("Too many identities in authentication reply: %d\n", auth->howmany); |
| |
| /* Return the first entry (if any). */ |
| return ssh_get_next_identity(auth, e, n, comment); |
| } |
| |
| /* |
| * Returns the next authentication identity for the agent. Other functions |
| * can be called between this and ssh_get_first_identity or two calls of this |
| * function. This returns 0 if there are no more identities. The caller |
| * must free comment after a successful return. |
| */ |
| |
| int |
| ssh_get_next_identity(AuthenticationConnection *auth, |
| BIGNUM *e, BIGNUM *n, char **comment) |
| { |
| unsigned int bits; |
| |
| /* Return failure if no more entries. */ |
| if (auth->howmany <= 0) |
| return 0; |
| |
| /* |
| * Get the next entry from the packet. These will abort with a fatal |
| * error if the packet is too short or contains corrupt data. |
| */ |
| bits = buffer_get_int(&auth->identities); |
| buffer_get_bignum(&auth->identities, e); |
| buffer_get_bignum(&auth->identities, n); |
| *comment = buffer_get_string(&auth->identities, NULL); |
| |
| if (bits != BN_num_bits(n)) |
| error("Warning: identity keysize mismatch: actual %d, announced %u", |
| BN_num_bits(n), bits); |
| |
| /* Decrement the number of remaining entries. */ |
| auth->howmany--; |
| |
| return 1; |
| } |
| |
| /* |
| * Generates a random challenge, sends it to the agent, and waits for |
| * response from the agent. Returns true (non-zero) if the agent gave the |
| * correct answer, zero otherwise. Response type selects the style of |
| * response desired, with 0 corresponding to protocol version 1.0 (no longer |
| * supported) and 1 corresponding to protocol version 1.1. |
| */ |
| |
| int |
| ssh_decrypt_challenge(AuthenticationConnection *auth, |
| BIGNUM* e, BIGNUM *n, BIGNUM *challenge, |
| unsigned char session_id[16], |
| unsigned int response_type, |
| unsigned char response[16]) |
| { |
| Buffer buffer; |
| unsigned char buf[8192]; |
| int len, l, i; |
| |
| /* Response type 0 is no longer supported. */ |
| if (response_type == 0) |
| fatal("Compatibility with ssh protocol version 1.0 no longer supported."); |
| |
| /* Format a message to the agent. */ |
| buf[0] = SSH_AGENTC_RSA_CHALLENGE; |
| buffer_init(&buffer); |
| buffer_append(&buffer, (char *) buf, 1); |
| buffer_put_int(&buffer, BN_num_bits(n)); |
| buffer_put_bignum(&buffer, e); |
| buffer_put_bignum(&buffer, n); |
| buffer_put_bignum(&buffer, challenge); |
| buffer_append(&buffer, (char *) session_id, 16); |
| buffer_put_int(&buffer, response_type); |
| |
| /* Get the length of the message, and format it in the buffer. */ |
| len = buffer_len(&buffer); |
| PUT_32BIT(buf, len); |
| |
| /* Send the length and then the packet to the agent. */ |
| if (atomicio(write, auth->fd, buf, 4) != 4 || |
| atomicio(write, auth->fd, buffer_ptr(&buffer), |
| buffer_len(&buffer)) != buffer_len(&buffer)) { |
| error("Error writing to authentication socket."); |
| error_cleanup: |
| buffer_free(&buffer); |
| 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."); |
| goto error_cleanup; |
| } |
| len -= l; |
| } |
| |
| /* Extract the length, and check it for sanity. */ |
| len = GET_32BIT(buf); |
| if (len > 256 * 1024) |
| fatal("Authentication response too long: %d", len); |
| |
| /* Read the rest of the response in tothe buffer. */ |
| buffer_clear(&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."); |
| goto error_cleanup; |
| } |
| buffer_append(&buffer, (char *) buf, l); |
| len -= l; |
| } |
| |
| /* Get the type of the packet. */ |
| buffer_get(&buffer, (char *) buf, 1); |
| |
| /* Check for agent failure message. */ |
| if (buf[0] == SSH_AGENT_FAILURE) { |
| log("Agent admitted failure to authenticate using the key."); |
| goto error_cleanup; |
| } |
| /* Now it must be an authentication response packet. */ |
| if (buf[0] != SSH_AGENT_RSA_RESPONSE) |
| fatal("Bad authentication response: %d", buf[0]); |
| |
| /* |
| * Get the response from the packet. This will abort with a fatal |
| * error if the packet is corrupt. |
| */ |
| for (i = 0; i < 16; i++) |
| response[i] = buffer_get_char(&buffer); |
| |
| /* The buffer containing the packet is no longer needed. */ |
| buffer_free(&buffer); |
| |
| /* Correct answer. */ |
| return 1; |
| } |
| |
| /* |
| * Adds an identity to the authentication server. This call is not meant to |
| * be used by normal applications. |
| */ |
| |
| int |
| ssh_add_identity(AuthenticationConnection *auth, |
| RSA * key, const char *comment) |
| { |
| Buffer buffer; |
| unsigned char buf[8192]; |
| int len, l, type; |
| |
| /* Format a message to the agent. */ |
| buffer_init(&buffer); |
| buffer_put_char(&buffer, SSH_AGENTC_ADD_RSA_IDENTITY); |
| buffer_put_int(&buffer, BN_num_bits(key->n)); |
| buffer_put_bignum(&buffer, key->n); |
| buffer_put_bignum(&buffer, key->e); |
| buffer_put_bignum(&buffer, key->d); |
| /* To keep within the protocol: p < q for ssh. in SSL p > q */ |
| buffer_put_bignum(&buffer, key->iqmp); /* ssh key->u */ |
| buffer_put_bignum(&buffer, key->q); /* ssh key->p, SSL key->q */ |
| buffer_put_bignum(&buffer, key->p); /* ssh key->q, SSL key->p */ |
| buffer_put_string(&buffer, comment, strlen(comment)); |
| |
| /* Get the length of the message, and format it in the buffer. */ |
| len = buffer_len(&buffer); |
| PUT_32BIT(buf, len); |
| |
| /* Send the length and then the packet to the agent. */ |
| if (atomicio(write, auth->fd, buf, 4) != 4 || |
| atomicio(write, auth->fd, buffer_ptr(&buffer), |
| buffer_len(&buffer)) != buffer_len(&buffer)) { |
| error("Error writing to authentication socket."); |
| error_cleanup: |
| buffer_free(&buffer); |
| 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."); |
| goto error_cleanup; |
| } |
| len -= l; |
| } |
| |
| /* Extract the length, and check it for sanity. */ |
| len = GET_32BIT(buf); |
| if (len > 256 * 1024) |
| fatal("Add identity response too long: %d", len); |
| |
| /* Read the rest of the response in tothe buffer. */ |
| buffer_clear(&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."); |
| goto error_cleanup; |
| } |
| 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 add identity from authentication agent: %d", |
| type); |
| } |
| /* NOTREACHED */ |
| return 0; |
| } |
| |
| /* |
| * Removes an identity from the authentication server. This call is not |
| * meant to be used by normal applications. |
| */ |
| |
| int |
| ssh_remove_identity(AuthenticationConnection *auth, RSA *key) |
| { |
| Buffer buffer; |
| unsigned char buf[8192]; |
| int len, l, type; |
| |
| /* Format a message to the agent. */ |
| buffer_init(&buffer); |
| buffer_put_char(&buffer, SSH_AGENTC_REMOVE_RSA_IDENTITY); |
| buffer_put_int(&buffer, BN_num_bits(key->n)); |
| buffer_put_bignum(&buffer, key->e); |
| buffer_put_bignum(&buffer, key->n); |
| |
| /* Get the length of the message, and format it in the buffer. */ |
| len = buffer_len(&buffer); |
| PUT_32BIT(buf, len); |
| |
| /* Send the length and then the packet to the agent. */ |
| if (atomicio(write, auth->fd, buf, 4) != 4 || |
| atomicio(write, auth->fd, buffer_ptr(&buffer), |
| buffer_len(&buffer)) != buffer_len(&buffer)) { |
| error("Error writing to authentication socket."); |
| error_cleanup: |
| buffer_free(&buffer); |
| 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."); |
| goto error_cleanup; |
| } |
| 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 in tothe buffer. */ |
| buffer_clear(&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."); |
| goto error_cleanup; |
| } |
| 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; |
| } |
| |
| /* |
| * 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]; |
| 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; |
| } |