From fc557ff7d97438559e69347575f5aa8ef03a5f50 Mon Sep 17 00:00:00 2001 From: markm Date: Thu, 24 Feb 2000 14:29:47 +0000 Subject: Vendor import of OpenSSH. --- crypto/openssh/ssh-agent.c | 653 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 653 insertions(+) create mode 100644 crypto/openssh/ssh-agent.c (limited to 'crypto/openssh/ssh-agent.c') diff --git a/crypto/openssh/ssh-agent.c b/crypto/openssh/ssh-agent.c new file mode 100644 index 0000000..6646956 --- /dev/null +++ b/crypto/openssh/ssh-agent.c @@ -0,0 +1,653 @@ +/* $OpenBSD: ssh-agent.c,v 1.25 2000/01/02 21:51:03 markus Exp $ */ + +/* + * Author: Tatu Ylonen + * Copyright (c) 1995 Tatu Ylonen , Espoo, Finland + * All rights reserved + * Created: Wed Mar 29 03:46:59 1995 ylo + * The authentication agent program. + */ + +#include "includes.h" +RCSID("$OpenBSD: ssh-agent.c,v 1.25 2000/01/02 21:51:03 markus Exp $"); + +#include "ssh.h" +#include "rsa.h" +#include "authfd.h" +#include "buffer.h" +#include "bufaux.h" +#include "xmalloc.h" +#include "packet.h" +#include "getput.h" +#include "mpaux.h" + +#include + +typedef struct { + int fd; + enum { + AUTH_UNUSED, AUTH_SOCKET, AUTH_CONNECTION + } type; + Buffer input; + Buffer output; +} SocketEntry; + +unsigned int sockets_alloc = 0; +SocketEntry *sockets = NULL; + +typedef struct { + RSA *key; + char *comment; +} Identity; + +unsigned int num_identities = 0; +Identity *identities = NULL; + +int max_fd = 0; + +/* pid of shell == parent of agent */ +int parent_pid = -1; + +/* pathname and directory for AUTH_SOCKET */ +char socket_name[1024]; +char socket_dir[1024]; + +extern char *__progname; + +void +process_request_identity(SocketEntry *e) +{ + Buffer msg; + int i; + + buffer_init(&msg); + buffer_put_char(&msg, SSH_AGENT_RSA_IDENTITIES_ANSWER); + buffer_put_int(&msg, num_identities); + for (i = 0; i < num_identities; i++) { + buffer_put_int(&msg, BN_num_bits(identities[i].key->n)); + buffer_put_bignum(&msg, identities[i].key->e); + buffer_put_bignum(&msg, identities[i].key->n); + buffer_put_string(&msg, identities[i].comment, + strlen(identities[i].comment)); + } + buffer_put_int(&e->output, buffer_len(&msg)); + buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg)); + buffer_free(&msg); +} + +void +process_authentication_challenge(SocketEntry *e) +{ + int i, pub_bits, len; + BIGNUM *pub_e, *pub_n, *challenge; + Buffer msg; + MD5_CTX md; + unsigned char buf[32], mdbuf[16], session_id[16]; + unsigned int response_type; + + buffer_init(&msg); + pub_e = BN_new(); + pub_n = BN_new(); + challenge = BN_new(); + pub_bits = buffer_get_int(&e->input); + buffer_get_bignum(&e->input, pub_e); + buffer_get_bignum(&e->input, pub_n); + buffer_get_bignum(&e->input, challenge); + if (buffer_len(&e->input) == 0) { + /* Compatibility code for old servers. */ + memset(session_id, 0, 16); + response_type = 0; + } else { + /* New code. */ + buffer_get(&e->input, (char *) session_id, 16); + response_type = buffer_get_int(&e->input); + } + for (i = 0; i < num_identities; i++) + if (pub_bits == BN_num_bits(identities[i].key->n) && + BN_cmp(pub_e, identities[i].key->e) == 0 && + BN_cmp(pub_n, identities[i].key->n) == 0) { + /* Decrypt the challenge using the private key. */ + rsa_private_decrypt(challenge, challenge, identities[i].key); + + /* Compute the desired response. */ + switch (response_type) { + case 0:/* As of protocol 1.0 */ + /* This response type is no longer supported. */ + log("Compatibility with ssh protocol 1.0 no longer supported."); + buffer_put_char(&msg, SSH_AGENT_FAILURE); + goto send; + + case 1:/* As of protocol 1.1 */ + /* The response is MD5 of decrypted challenge plus session id. */ + len = BN_num_bytes(challenge); + + if (len <= 0 || len > 32) { + fatal("process_authentication_challenge: " + "bad challenge length %d", len); + } + memset(buf, 0, 32); + BN_bn2bin(challenge, buf + 32 - len); + MD5_Init(&md); + MD5_Update(&md, buf, 32); + MD5_Update(&md, session_id, 16); + MD5_Final(mdbuf, &md); + break; + + default: + fatal("process_authentication_challenge: bad response_type %d", + response_type); + break; + } + + /* Send the response. */ + buffer_put_char(&msg, SSH_AGENT_RSA_RESPONSE); + for (i = 0; i < 16; i++) + buffer_put_char(&msg, mdbuf[i]); + + goto send; + } + /* Unknown identity. Send failure. */ + buffer_put_char(&msg, SSH_AGENT_FAILURE); +send: + buffer_put_int(&e->output, buffer_len(&msg)); + buffer_append(&e->output, buffer_ptr(&msg), + buffer_len(&msg)); + buffer_free(&msg); + BN_clear_free(pub_e); + BN_clear_free(pub_n); + BN_clear_free(challenge); +} + +void +process_remove_identity(SocketEntry *e) +{ + unsigned int bits; + unsigned int i; + BIGNUM *dummy, *n; + + dummy = BN_new(); + n = BN_new(); + + /* Get the key from the packet. */ + bits = buffer_get_int(&e->input); + buffer_get_bignum(&e->input, dummy); + buffer_get_bignum(&e->input, n); + + if (bits != BN_num_bits(n)) + error("Warning: identity keysize mismatch: actual %d, announced %d", + BN_num_bits(n), bits); + + /* Check if we have the key. */ + for (i = 0; i < num_identities; i++) + if (BN_cmp(identities[i].key->n, n) == 0) { + /* + * We have this key. Free the old key. Since we + * don\'t want to leave empty slots in the middle of + * the array, we actually free the key there and copy + * data from the last entry. + */ + RSA_free(identities[i].key); + xfree(identities[i].comment); + if (i < num_identities - 1) + identities[i] = identities[num_identities - 1]; + num_identities--; + BN_clear_free(dummy); + BN_clear_free(n); + + /* Send success. */ + buffer_put_int(&e->output, 1); + buffer_put_char(&e->output, SSH_AGENT_SUCCESS); + return; + } + /* We did not have the key. */ + BN_clear(dummy); + BN_clear(n); + + /* Send failure. */ + buffer_put_int(&e->output, 1); + buffer_put_char(&e->output, SSH_AGENT_FAILURE); +} + +/* + * Removes all identities from the agent. + */ +void +process_remove_all_identities(SocketEntry *e) +{ + unsigned int i; + + /* Loop over all identities and clear the keys. */ + for (i = 0; i < num_identities; i++) { + RSA_free(identities[i].key); + xfree(identities[i].comment); + } + + /* Mark that there are no identities. */ + num_identities = 0; + + /* Send success. */ + buffer_put_int(&e->output, 1); + buffer_put_char(&e->output, SSH_AGENT_SUCCESS); + return; +} + +/* + * Adds an identity to the agent. + */ +void +process_add_identity(SocketEntry *e) +{ + RSA *k; + int i; + BIGNUM *aux; + BN_CTX *ctx; + + if (num_identities == 0) + identities = xmalloc(sizeof(Identity)); + else + identities = xrealloc(identities, (num_identities + 1) * sizeof(Identity)); + + identities[num_identities].key = RSA_new(); + k = identities[num_identities].key; + buffer_get_int(&e->input); /* bits */ + k->n = BN_new(); + buffer_get_bignum(&e->input, k->n); + k->e = BN_new(); + buffer_get_bignum(&e->input, k->e); + k->d = BN_new(); + buffer_get_bignum(&e->input, k->d); + k->iqmp = BN_new(); + buffer_get_bignum(&e->input, k->iqmp); + /* SSH and SSL have p and q swapped */ + k->q = BN_new(); + buffer_get_bignum(&e->input, k->q); /* p */ + k->p = BN_new(); + buffer_get_bignum(&e->input, k->p); /* q */ + + /* Generate additional parameters */ + aux = BN_new(); + ctx = BN_CTX_new(); + + BN_sub(aux, k->q, BN_value_one()); + k->dmq1 = BN_new(); + BN_mod(k->dmq1, k->d, aux, ctx); + + BN_sub(aux, k->p, BN_value_one()); + k->dmp1 = BN_new(); + BN_mod(k->dmp1, k->d, aux, ctx); + + BN_clear_free(aux); + BN_CTX_free(ctx); + + identities[num_identities].comment = buffer_get_string(&e->input, NULL); + + /* Check if we already have the key. */ + for (i = 0; i < num_identities; i++) + if (BN_cmp(identities[i].key->n, k->n) == 0) { + /* + * We already have this key. Clear and free the new + * data and return success. + */ + RSA_free(k); + xfree(identities[num_identities].comment); + + /* Send success. */ + buffer_put_int(&e->output, 1); + buffer_put_char(&e->output, SSH_AGENT_SUCCESS); + return; + } + /* Increment the number of identities. */ + num_identities++; + + /* Send a success message. */ + buffer_put_int(&e->output, 1); + buffer_put_char(&e->output, SSH_AGENT_SUCCESS); +} + +void +process_message(SocketEntry *e) +{ + unsigned int msg_len; + unsigned int type; + unsigned char *cp; + if (buffer_len(&e->input) < 5) + return; /* Incomplete message. */ + cp = (unsigned char *) buffer_ptr(&e->input); + msg_len = GET_32BIT(cp); + if (msg_len > 256 * 1024) { + shutdown(e->fd, SHUT_RDWR); + close(e->fd); + e->type = AUTH_UNUSED; + return; + } + if (buffer_len(&e->input) < msg_len + 4) + return; + buffer_consume(&e->input, 4); + type = buffer_get_char(&e->input); + + switch (type) { + case SSH_AGENTC_REQUEST_RSA_IDENTITIES: + process_request_identity(e); + break; + case SSH_AGENTC_RSA_CHALLENGE: + process_authentication_challenge(e); + break; + case SSH_AGENTC_ADD_RSA_IDENTITY: + process_add_identity(e); + break; + case SSH_AGENTC_REMOVE_RSA_IDENTITY: + process_remove_identity(e); + break; + case SSH_AGENTC_REMOVE_ALL_RSA_IDENTITIES: + process_remove_all_identities(e); + break; + default: + /* Unknown message. Respond with failure. */ + error("Unknown message %d", type); + buffer_clear(&e->input); + buffer_put_int(&e->output, 1); + buffer_put_char(&e->output, SSH_AGENT_FAILURE); + break; + } +} + +void +new_socket(int type, int fd) +{ + unsigned int i, old_alloc; + if (fcntl(fd, F_SETFL, O_NONBLOCK) < 0) + error("fcntl O_NONBLOCK: %s", strerror(errno)); + + if (fd > max_fd) + max_fd = fd; + + for (i = 0; i < sockets_alloc; i++) + if (sockets[i].type == AUTH_UNUSED) { + sockets[i].fd = fd; + sockets[i].type = type; + buffer_init(&sockets[i].input); + buffer_init(&sockets[i].output); + return; + } + old_alloc = sockets_alloc; + sockets_alloc += 10; + if (sockets) + sockets = xrealloc(sockets, sockets_alloc * sizeof(sockets[0])); + else + sockets = xmalloc(sockets_alloc * sizeof(sockets[0])); + for (i = old_alloc; i < sockets_alloc; i++) + sockets[i].type = AUTH_UNUSED; + sockets[old_alloc].type = type; + sockets[old_alloc].fd = fd; + buffer_init(&sockets[old_alloc].input); + buffer_init(&sockets[old_alloc].output); +} + +void +prepare_select(fd_set *readset, fd_set *writeset) +{ + unsigned int i; + for (i = 0; i < sockets_alloc; i++) + switch (sockets[i].type) { + case AUTH_SOCKET: + case AUTH_CONNECTION: + FD_SET(sockets[i].fd, readset); + if (buffer_len(&sockets[i].output) > 0) + FD_SET(sockets[i].fd, writeset); + break; + case AUTH_UNUSED: + break; + default: + fatal("Unknown socket type %d", sockets[i].type); + break; + } +} + +void +after_select(fd_set *readset, fd_set *writeset) +{ + unsigned int i; + int len, sock; + char buf[1024]; + struct sockaddr_un sunaddr; + + for (i = 0; i < sockets_alloc; i++) + switch (sockets[i].type) { + case AUTH_UNUSED: + break; + case AUTH_SOCKET: + if (FD_ISSET(sockets[i].fd, readset)) { + len = sizeof(sunaddr); + sock = accept(sockets[i].fd, (struct sockaddr *) & sunaddr, &len); + if (sock < 0) { + perror("accept from AUTH_SOCKET"); + break; + } + new_socket(AUTH_CONNECTION, sock); + } + break; + case AUTH_CONNECTION: + if (buffer_len(&sockets[i].output) > 0 && + FD_ISSET(sockets[i].fd, writeset)) { + len = write(sockets[i].fd, buffer_ptr(&sockets[i].output), + buffer_len(&sockets[i].output)); + if (len <= 0) { + shutdown(sockets[i].fd, SHUT_RDWR); + close(sockets[i].fd); + sockets[i].type = AUTH_UNUSED; + break; + } + buffer_consume(&sockets[i].output, len); + } + if (FD_ISSET(sockets[i].fd, readset)) { + len = read(sockets[i].fd, buf, sizeof(buf)); + if (len <= 0) { + shutdown(sockets[i].fd, SHUT_RDWR); + close(sockets[i].fd); + sockets[i].type = AUTH_UNUSED; + break; + } + buffer_append(&sockets[i].input, buf, len); + process_message(&sockets[i]); + } + break; + default: + fatal("Unknown type %d", sockets[i].type); + } +} + +void +check_parent_exists(int sig) +{ + if (kill(parent_pid, 0) < 0) { + /* printf("Parent has died - Authentication agent exiting.\n"); */ + exit(1); + } + signal(SIGALRM, check_parent_exists); + alarm(10); +} + +void +cleanup_socket(void) +{ + remove(socket_name); + rmdir(socket_dir); +} + +void +cleanup_exit(int i) +{ + cleanup_socket(); + exit(i); +} + +void +usage() +{ + fprintf(stderr, "ssh-agent version %s\n", SSH_VERSION); + fprintf(stderr, "Usage: %s [-c | -s] [-k] [command {args...]]\n", + __progname); + exit(1); +} + +int +main(int ac, char **av) +{ + fd_set readset, writeset; + int sock, c_flag = 0, k_flag = 0, s_flag = 0, ch; + struct sockaddr_un sunaddr; + pid_t pid; + char *shell, *format, *pidstr, pidstrbuf[1 + 3 * sizeof pid]; + + /* check if RSA support exists */ + if (rsa_alive() == 0) { + fprintf(stderr, + "%s: no RSA support in libssl and libcrypto. See ssl(8).\n", + __progname); + exit(1); + } + while ((ch = getopt(ac, av, "cks")) != -1) { + switch (ch) { + case 'c': + if (s_flag) + usage(); + c_flag++; + break; + case 'k': + k_flag++; + break; + case 's': + if (c_flag) + usage(); + s_flag++; + break; + default: + usage(); + } + } + ac -= optind; + av += optind; + + if (ac > 0 && (c_flag || k_flag || s_flag)) + usage(); + + if (ac == 0 && !c_flag && !k_flag && !s_flag) { + shell = getenv("SHELL"); + if (shell != NULL && strncmp(shell + strlen(shell) - 3, "csh", 3) == 0) + c_flag = 1; + } + if (k_flag) { + pidstr = getenv(SSH_AGENTPID_ENV_NAME); + if (pidstr == NULL) { + fprintf(stderr, "%s not set, cannot kill agent\n", + SSH_AGENTPID_ENV_NAME); + exit(1); + } + pid = atoi(pidstr); + if (pid < 1) { /* XXX PID_MAX check too */ + fprintf(stderr, "%s=\"%s\", which is not a good PID\n", + SSH_AGENTPID_ENV_NAME, pidstr); + exit(1); + } + if (kill(pid, SIGTERM) == -1) { + perror("kill"); + exit(1); + } + format = c_flag ? "unsetenv %s;\n" : "unset %s;\n"; + printf(format, SSH_AUTHSOCKET_ENV_NAME); + printf(format, SSH_AGENTPID_ENV_NAME); + printf("echo Agent pid %d killed;\n", pid); + exit(0); + } + parent_pid = getpid(); + + /* Create private directory for agent socket */ + strlcpy(socket_dir, "/tmp/ssh-XXXXXXXX", sizeof socket_dir); + if (mkdtemp(socket_dir) == NULL) { + perror("mkdtemp: private socket dir"); + exit(1); + } + snprintf(socket_name, sizeof socket_name, "%s/agent.%d", socket_dir, + parent_pid); + + /* + * Create socket early so it will exist before command gets run from + * the parent. + */ + sock = socket(AF_UNIX, SOCK_STREAM, 0); + if (sock < 0) { + perror("socket"); + cleanup_exit(1); + } + memset(&sunaddr, 0, sizeof(sunaddr)); + sunaddr.sun_family = AF_UNIX; + strlcpy(sunaddr.sun_path, socket_name, sizeof(sunaddr.sun_path)); + if (bind(sock, (struct sockaddr *) & sunaddr, sizeof(sunaddr)) < 0) { + perror("bind"); + cleanup_exit(1); + } + if (listen(sock, 5) < 0) { + perror("listen"); + cleanup_exit(1); + } + /* + * Fork, and have the parent execute the command, if any, or present + * the socket data. The child continues as the authentication agent. + */ + pid = fork(); + if (pid == -1) { + perror("fork"); + exit(1); + } + if (pid != 0) { /* Parent - execute the given command. */ + close(sock); + snprintf(pidstrbuf, sizeof pidstrbuf, "%d", pid); + if (ac == 0) { + format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n"; + printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name, + SSH_AUTHSOCKET_ENV_NAME); + printf(format, SSH_AGENTPID_ENV_NAME, pidstrbuf, + SSH_AGENTPID_ENV_NAME); + printf("echo Agent pid %d;\n", pid); + exit(0); + } + setenv(SSH_AUTHSOCKET_ENV_NAME, socket_name, 1); + setenv(SSH_AGENTPID_ENV_NAME, pidstrbuf, 1); + execvp(av[0], av); + perror(av[0]); + exit(1); + } + close(0); + close(1); + close(2); + + if (setsid() == -1) { + perror("setsid"); + cleanup_exit(1); + } + if (atexit(cleanup_socket) < 0) { + perror("atexit"); + cleanup_exit(1); + } + new_socket(AUTH_SOCKET, sock); + if (ac > 0) { + signal(SIGALRM, check_parent_exists); + alarm(10); + } + signal(SIGINT, SIG_IGN); + signal(SIGPIPE, SIG_IGN); + signal(SIGHUP, cleanup_exit); + signal(SIGTERM, cleanup_exit); + while (1) { + FD_ZERO(&readset); + FD_ZERO(&writeset); + prepare_select(&readset, &writeset); + if (select(max_fd + 1, &readset, &writeset, NULL, NULL) < 0) { + if (errno == EINTR) + continue; + exit(1); + } + after_select(&readset, &writeset); + } + /* NOTREACHED */ +} -- cgit v1.1