Vendor import of OpenSSH.

1 files changed, 653 insertions, 0 deletions

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 <ylo@cs.hut.fi>
+ * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, 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 <ssl/md5.h>
+
+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 */
+}