X-Git-Url: http://andersk.mit.edu/gitweb/openssh.git/blobdiff_plain/b03bd394bf57de8882bed56e8e3a0ab8b963d0c5..23aa123701299d88160cdd67e871a2244082afa6:/ssh-agent.c

diff --git a/ssh-agent.c b/ssh-agent.c
index 55704e49..33596c47 100644
--- a/ssh-agent.c
+++ b/ssh-agent.c
@@ -1,5 +1,3 @@
-/*	$OpenBSD: ssh-agent.c,v 1.45 2000/12/19 23:17:58 markus Exp $	*/
-
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -12,8 +10,7 @@
  * incompatible with the protocol description in the RFC file, it must be
  * called by a name other than "ssh" or "Secure Shell".
  *
- * SSH2 implementation,
- * Copyright (c) 2000 Markus Friedl. All rights reserved.
+ * Copyright (c) 2000, 2001 Markus Friedl.  All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ -37,31 +34,36 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: ssh-agent.c,v 1.45 2000/12/19 23:17:58 markus Exp $");
+#include "openbsd-compat/fake-queue.h"
+RCSID("$OpenBSD: ssh-agent.c,v 1.85 2002/04/02 11:49:39 markus Exp $");
+
+#include <openssl/evp.h>
+#include <openssl/md5.h>
 
 #include "ssh.h"
 #include "rsa.h"
 #include "buffer.h"
 #include "bufaux.h"
 #include "xmalloc.h"
-#include "packet.h"
 #include "getput.h"
-#include "mpaux.h"
-
-#include <openssl/evp.h>
-#include <openssl/md5.h>
-#include <openssl/dsa.h>
-#include <openssl/rsa.h>
 #include "key.h"
 #include "authfd.h"
-#include "kex.h"
 #include "compat.h"
+#include "log.h"
+
+#ifdef SMARTCARD
+#include "scard.h"
+#endif
+
+typedef enum {
+	AUTH_UNUSED,
+	AUTH_SOCKET,
+	AUTH_CONNECTION
+} sock_type;
 
 typedef struct {
 	int fd;
-	enum {
-		AUTH_UNUSED, AUTH_SOCKET, AUTH_CONNECTION
-	} type;
+	sock_type type;
 	Buffer input;
 	Buffer output;
 } SocketEntry;
@@ -69,14 +71,15 @@ typedef struct {
 u_int sockets_alloc = 0;
 SocketEntry *sockets = NULL;
 
-typedef struct {
+typedef struct identity {
+	TAILQ_ENTRY(identity) next;
 	Key *key;
 	char *comment;
 } Identity;
 
 typedef struct {
 	int nentries;
-	Identity *identities;
+	TAILQ_HEAD(idqueue, identity) idlist;
 } Idtab;
 
 /* private key table, one per protocol version */
@@ -97,18 +100,18 @@ extern char *__progname;
 char *__progname;
 #endif
 
-void
+static void
 idtab_init(void)
 {
 	int i;
-	for (i = 0; i <=2; i++){
-		idtable[i].identities = NULL;
+	for (i = 0; i <=2; i++) {
+		TAILQ_INIT(&idtable[i].idlist);
 		idtable[i].nentries = 0;
 	}
 }
 
 /* return private key table for requested protocol version */
-Idtab *
+static Idtab *
 idtab_lookup(int version)
 {
 	if (version < 1 || version > 2)
@@ -117,35 +120,40 @@ idtab_lookup(int version)
 }
 
 /* return matching private key for given public key */
-Key *
-lookup_private_key(Key *key, int *idx, int version)
+static Identity *
+lookup_identity(Key *key, int version)
 {
-	int i;
+	Identity *id;
+
 	Idtab *tab = idtab_lookup(version);
-	for (i = 0; i < tab->nentries; i++) {
-		if (key_equal(key, tab->identities[i].key)) {
-			if (idx != NULL)
-				*idx = i;
-			return tab->identities[i].key;
-		}
+	TAILQ_FOREACH(id, &tab->idlist, next) {
+		if (key_equal(key, id->key))
+			return (id);
 	}
-	return NULL;
+	return (NULL);
+}
+
+static void
+free_identity(Identity *id)
+{
+	key_free(id->key);
+	xfree(id->comment);
+	xfree(id);
 }
 
 /* send list of supported public keys to 'client' */
-void
+static void
 process_request_identities(SocketEntry *e, int version)
 {
 	Idtab *tab = idtab_lookup(version);
 	Buffer msg;
-	int i;
+	Identity *id;
 
 	buffer_init(&msg);
 	buffer_put_char(&msg, (version == 1) ?
 	    SSH_AGENT_RSA_IDENTITIES_ANSWER : SSH2_AGENT_IDENTITIES_ANSWER);
 	buffer_put_int(&msg, tab->nentries);
-	for (i = 0; i < tab->nentries; i++) {
-		Identity *id = &tab->identities[i];
+	TAILQ_FOREACH(id, &tab->idlist, next) {
 		if (id->key->type == KEY_RSA1) {
 			buffer_put_int(&msg, BN_num_bits(id->key->rsa->n));
 			buffer_put_bignum(&msg, id->key->rsa->e);
@@ -165,10 +173,11 @@ process_request_identities(SocketEntry *e, int version)
 }
 
 /* ssh1 only */
-void
+static void
 process_authentication_challenge1(SocketEntry *e)
 {
-	Key *key, *private;
+	Identity *id;
+	Key *key;
 	BIGNUM *challenge;
 	int i, len;
 	Buffer msg;
@@ -178,7 +187,8 @@ process_authentication_challenge1(SocketEntry *e)
 
 	buffer_init(&msg);
 	key = key_new(KEY_RSA1);
-	challenge = BN_new();
+	if ((challenge = BN_new()) == NULL)
+		fatal("process_authentication_challenge1: BN_new failed");
 
 	buffer_get_int(&e->input);				/* ignored */
 	buffer_get_bignum(&e->input, key->rsa->e);
@@ -188,15 +198,17 @@ process_authentication_challenge1(SocketEntry *e)
 	/* Only protocol 1.1 is supported */
 	if (buffer_len(&e->input) == 0)
 		goto failure;
-	buffer_get(&e->input, (char *) session_id, 16);
+	buffer_get(&e->input, session_id, 16);
 	response_type = buffer_get_int(&e->input);
 	if (response_type != 1)
 		goto failure;
 
-	private = lookup_private_key(key, NULL, 1);
-	if (private != NULL) {
+	id = lookup_identity(key, 1);
+	if (id != NULL) {
+		Key *private = id->key;
 		/* Decrypt the challenge using the private key. */
-		rsa_private_decrypt(challenge, challenge, private->rsa);
+		if (rsa_private_decrypt(challenge, challenge, private->rsa) <= 0)
+			goto failure;
 
 		/* The response is MD5 of decrypted challenge plus session id. */
 		len = BN_num_bytes(challenge);
@@ -230,11 +242,11 @@ send:
 }
 
 /* ssh2 only */
-void
+static void
 process_sign_request2(SocketEntry *e)
 {
 	extern int datafellows;
-	Key *key, *private;
+	Key *key;
 	u_char *blob, *data, *signature = NULL;
 	u_int blen, dlen, slen = 0;
 	int flags;
@@ -252,9 +264,9 @@ process_sign_request2(SocketEntry *e)
 
 	key = key_from_blob(blob, blen);
 	if (key != NULL) {
-		private = lookup_private_key(key, NULL, 2);
-		if (private != NULL)
-			ok = key_sign(private, &signature, &slen, data, dlen);
+		Identity *id = lookup_identity(key, 2);
+		if (id != NULL)
+			ok = key_sign(id->key, &signature, &slen, data, dlen);
 	}
 	key_free(key);
 	buffer_init(&msg);
@@ -275,16 +287,16 @@ process_sign_request2(SocketEntry *e)
 }
 
 /* shared */
-void
+static void
 process_remove_identity(SocketEntry *e, int version)
 {
-	Key *key = NULL, *private;
+	Key *key = NULL;
 	u_char *blob;
 	u_int blen;
 	u_int bits;
 	int success = 0;
 
-	switch(version){
+	switch (version) {
 	case 1:
 		key = key_new(KEY_RSA1);
 		bits = buffer_get_int(&e->input);
@@ -293,7 +305,7 @@ process_remove_identity(SocketEntry *e, int version)
 
 		if (bits != key_size(key))
 			log("Warning: identity keysize mismatch: actual %d, announced %d",
-			      key_size(key), bits);
+			    key_size(key), bits);
 		break;
 	case 2:
 		blob = buffer_get_string(&e->input, &blen);
@@ -302,9 +314,8 @@ process_remove_identity(SocketEntry *e, int version)
 		break;
 	}
 	if (key != NULL) {
-		int idx;
-		private = lookup_private_key(key, &idx, version);
-		if (private != NULL) {
+		Identity *id = lookup_identity(key, version);
+		if (id != NULL) {
 			/*
 			 * We have this key.  Free the old key.  Since we
 			 * don\'t want to leave empty slots in the middle of
@@ -313,19 +324,12 @@ process_remove_identity(SocketEntry *e, int version)
 			 * of the array.
 			 */
 			Idtab *tab = idtab_lookup(version);
-			key_free(tab->identities[idx].key);
-			xfree(tab->identities[idx].comment);
 			if (tab->nentries < 1)
 				fatal("process_remove_identity: "
 				    "internal error: tab->nentries %d",
 				    tab->nentries);
-			if (idx != tab->nentries - 1) {
-				int i;
-				for (i = idx; i < tab->nentries - 1; i++)
-					tab->identities[i] = tab->identities[i+1];
-			}
-			tab->identities[tab->nentries - 1].key = NULL;
-			tab->identities[tab->nentries - 1].comment = NULL;
+			TAILQ_REMOVE(&tab->idlist, id, next);
+			free_identity(id);
 			tab->nentries--;
 			success = 1;
 		}
@@ -336,16 +340,17 @@ process_remove_identity(SocketEntry *e, int version)
 	    success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE);
 }
 
-void
+static void
 process_remove_all_identities(SocketEntry *e, int version)
 {
-	u_int i;
 	Idtab *tab = idtab_lookup(version);
+	Identity *id;
 
 	/* Loop over all identities and clear the keys. */
-	for (i = 0; i < tab->nentries; i++) {
-		key_free(tab->identities[i].key);
-		xfree(tab->identities[i].comment);
+	for (id = TAILQ_FIRST(&tab->idlist); id;
+	    id = TAILQ_FIRST(&tab->idlist)) {
+		TAILQ_REMOVE(&tab->idlist, id, next);
+		free_identity(id);
 	}
 
 	/* Mark that there are no identities. */
@@ -357,26 +362,7 @@ process_remove_all_identities(SocketEntry *e, int version)
 	return;
 }
 
-void
-generate_additional_parameters(RSA *rsa)
-{
-	BIGNUM *aux;
-	BN_CTX *ctx;
-	/* Generate additional parameters */
-	aux = BN_new();
-	ctx = BN_CTX_new();
-
-	BN_sub(aux, rsa->q, BN_value_one());
-	BN_mod(rsa->dmq1, rsa->d, aux, ctx);
-
-	BN_sub(aux, rsa->p, BN_value_one());
-	BN_mod(rsa->dmp1, rsa->d, aux, ctx);
-
-	BN_clear_free(aux);
-	BN_CTX_free(ctx);
-}
-
-void
+static void
 process_add_identity(SocketEntry *e, int version)
 {
 	Key *k = NULL;
@@ -388,7 +374,7 @@ process_add_identity(SocketEntry *e, int version)
 	switch (version) {
 	case 1:
 		k = key_new_private(KEY_RSA1);
-		buffer_get_int(&e->input);		 	/* ignored */
+		buffer_get_int(&e->input);			/* ignored */
 		buffer_get_bignum(&e->input, k->rsa->n);
 		buffer_get_bignum(&e->input, k->rsa->e);
 		buffer_get_bignum(&e->input, k->rsa->d);
@@ -399,13 +385,13 @@ process_add_identity(SocketEntry *e, int version)
 		buffer_get_bignum(&e->input, k->rsa->p);	/* q */
 
 		/* Generate additional parameters */
-		generate_additional_parameters(k->rsa);
+		rsa_generate_additional_parameters(k->rsa);
 		break;
 	case 2:
 		type_name = buffer_get_string(&e->input, NULL);
-                type = key_type_from_name(type_name);
+		type = key_type_from_name(type_name);
 		xfree(type_name);
-		switch(type) {
+		switch (type) {
 		case KEY_DSA:
 			k = key_new_private(type);
 			buffer_get_bignum2(&e->input, k->dsa->p);
@@ -424,7 +410,7 @@ process_add_identity(SocketEntry *e, int version)
 			buffer_get_bignum2(&e->input, k->rsa->q);
 
 			/* Generate additional parameters */
-			generate_additional_parameters(k->rsa);
+			rsa_generate_additional_parameters(k->rsa);
 			break;
 		default:
 			buffer_clear(&e->input);
@@ -438,14 +424,11 @@ process_add_identity(SocketEntry *e, int version)
 		goto send;
 	}
 	success = 1;
-	if (lookup_private_key(k, NULL, version) == NULL) {
-		if (tab->nentries == 0)
-			tab->identities = xmalloc(sizeof(Identity));
-		else
-			tab->identities = xrealloc(tab->identities,
-			    (tab->nentries + 1) * sizeof(Identity));
-		tab->identities[tab->nentries].key = k;
-		tab->identities[tab->nentries].comment = comment;
+	if (lookup_identity(k, version) == NULL) {
+		Identity *id = xmalloc(sizeof(Identity));
+		id->key = k;
+		id->comment = comment;
+		TAILQ_INSERT_TAIL(&tab->idlist, id, next);
 		/* Increment the number of identities. */
 		tab->nentries++;
 	} else {
@@ -458,9 +441,93 @@ send:
 	    success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE);
 }
 
+
+#ifdef SMARTCARD
+static void
+process_add_smartcard_key (SocketEntry *e)
+{
+	Identity *id;
+	Idtab *tab;
+	Key **keys, *k;
+	char *sc_reader_id = NULL, *pin;
+	int i, version, success = 0;
+
+	sc_reader_id = buffer_get_string(&e->input, NULL);
+	pin = buffer_get_string(&e->input, NULL);
+	keys = sc_get_keys(sc_reader_id, pin);
+	xfree(sc_reader_id);
+	xfree(pin);
+
+	if (keys == NULL || keys[0] == NULL) {
+		error("sc_get_keys failed");
+		goto send;
+	}
+	for (i = 0; keys[i] != NULL; i++) {
+		k = keys[i];
+		version = k->type == KEY_RSA1 ? 1 : 2;
+		tab = idtab_lookup(version);
+		if (lookup_identity(k, version) == NULL) {
+			id = xmalloc(sizeof(Identity));
+			id->key = k;
+			id->comment = xstrdup("smartcard key");
+			TAILQ_INSERT_TAIL(&tab->idlist, id, next);
+			tab->nentries++;
+			success = 1;
+		} else {
+			key_free(k);
+		}
+		keys[i] = NULL;
+	}
+	xfree(keys);
+send:
+	buffer_put_int(&e->output, 1);
+	buffer_put_char(&e->output,
+	    success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE);
+}
+
+static void
+process_remove_smartcard_key(SocketEntry *e)
+{
+	Identity *id;
+	Idtab *tab;
+	Key **keys, *k = NULL;
+	char *sc_reader_id = NULL, *pin;
+	int i, version, success = 0;
+
+	sc_reader_id = buffer_get_string(&e->input, NULL);
+	pin = buffer_get_string(&e->input, NULL);
+	keys = sc_get_keys(sc_reader_id, pin);
+	xfree(sc_reader_id);
+	xfree(pin);
+
+	if (keys == NULL || keys[0] == NULL) {
+		error("sc_get_keys failed");
+		goto send;
+	}
+	for (i = 0; keys[i] != NULL; i++) {
+		k = keys[i];
+		version = k->type == KEY_RSA1 ? 1 : 2;
+		if ((id = lookup_identity(k, version)) != NULL) {
+			tab = idtab_lookup(version);
+                        TAILQ_REMOVE(&tab->idlist, id, next);
+			tab->nentries--;
+			free_identity(id);
+			success = 1;
+		}
+		key_free(k);
+		keys[i] = NULL;
+	}
+	xfree(keys);
+send:
+	buffer_put_int(&e->output, 1);
+	buffer_put_char(&e->output,
+	    success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE);
+}
+#endif /* SMARTCARD */
+
 /* dispatch incoming messages */
 
-void
+static void
 process_message(SocketEntry *e)
 {
 	u_int msg_len;
@@ -468,7 +535,7 @@ process_message(SocketEntry *e)
 	u_char *cp;
 	if (buffer_len(&e->input) < 5)
 		return;		/* Incomplete message. */
-	cp = (u_char *) buffer_ptr(&e->input);
+	cp = buffer_ptr(&e->input);
 	msg_len = GET_32BIT(cp);
 	if (msg_len > 256 * 1024) {
 		shutdown(e->fd, SHUT_RDWR);
@@ -481,6 +548,7 @@ process_message(SocketEntry *e)
 	buffer_consume(&e->input, 4);
 	type = buffer_get_char(&e->input);
 
+	debug("type %d", type);
 	switch (type) {
 	/* ssh1 */
 	case SSH_AGENTC_RSA_CHALLENGE:
@@ -514,6 +582,14 @@ process_message(SocketEntry *e)
 	case SSH2_AGENTC_REMOVE_ALL_IDENTITIES:
 		process_remove_all_identities(e, 2);
 		break;
+#ifdef SMARTCARD
+	case SSH_AGENTC_ADD_SMARTCARD_KEY:
+		process_add_smartcard_key(e);
+		break;
+	case SSH_AGENTC_REMOVE_SMARTCARD_KEY:
+		process_remove_smartcard_key(e);
+		break;
+#endif /* SMARTCARD */
 	default:
 		/* Unknown message.  Respond with failure. */
 		error("Unknown message %d", type);
@@ -524,8 +600,8 @@ process_message(SocketEntry *e)
 	}
 }
 
-void
-new_socket(int type, int fd)
+static void
+new_socket(sock_type type, int fd)
 {
 	u_int i, old_alloc;
 	if (fcntl(fd, F_SETFL, O_NONBLOCK) < 0)
@@ -556,17 +632,17 @@ new_socket(int type, int fd)
 	buffer_init(&sockets[old_alloc].output);
 }
 
-void
-prepare_select(fd_set *readset, fd_set *writeset)
+static int
+prepare_select(fd_set **fdrp, fd_set **fdwp, int *fdl, int *nallocp)
 {
-	u_int i;
-	for (i = 0; i < sockets_alloc; i++)
+	u_int i, sz;
+	int n = 0;
+
+	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);
+			n = MAX(n, sockets[i].fd);
 			break;
 		case AUTH_UNUSED:
 			break;
@@ -574,9 +650,40 @@ prepare_select(fd_set *readset, fd_set *writeset)
 			fatal("Unknown socket type %d", sockets[i].type);
 			break;
 		}
+	}
+
+	sz = howmany(n+1, NFDBITS) * sizeof(fd_mask);
+	if (*fdrp == NULL || sz > *nallocp) {
+		if (*fdrp)
+			xfree(*fdrp);
+		if (*fdwp)
+			xfree(*fdwp);
+		*fdrp = xmalloc(sz);
+		*fdwp = xmalloc(sz);
+		*nallocp = sz;
+	}
+	if (n < *fdl)
+		debug("XXX shrink: %d < %d", n, *fdl);
+	*fdl = n;
+	memset(*fdrp, 0, sz);
+	memset(*fdwp, 0, sz);
+
+	for (i = 0; i < sockets_alloc; i++) {
+		switch (sockets[i].type) {
+		case AUTH_SOCKET:
+		case AUTH_CONNECTION:
+			FD_SET(sockets[i].fd, *fdrp);
+			if (buffer_len(&sockets[i].output) > 0)
+				FD_SET(sockets[i].fd, *fdwp);
+			break;
+		default:
+			break;
+		}
+	}
+	return (1);
 }
 
-void
+static void
 after_select(fd_set *readset, fd_set *writeset)
 {
 	u_int i;
@@ -592,9 +699,11 @@ after_select(fd_set *readset, fd_set *writeset)
 		case AUTH_SOCKET:
 			if (FD_ISSET(sockets[i].fd, readset)) {
 				slen = sizeof(sunaddr);
-				sock = accept(sockets[i].fd, (struct sockaddr *) & sunaddr, &slen);
+				sock = accept(sockets[i].fd,
+				    (struct sockaddr *) &sunaddr, &slen);
 				if (sock < 0) {
-					perror("accept from AUTH_SOCKET");
+					error("accept from AUTH_SOCKET: %s",
+					    strerror(errno));
 					break;
 				}
 				new_socket(AUTH_CONNECTION, sock);
@@ -603,8 +712,15 @@ after_select(fd_set *readset, fd_set *writeset)
 		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));
+				do {
+					len = write(sockets[i].fd,
+					    buffer_ptr(&sockets[i].output),
+					    buffer_len(&sockets[i].output));
+					if (len == -1 && (errno == EAGAIN ||
+					    errno == EINTR))
+						continue;
+					break;
+				} while (1);
 				if (len <= 0) {
 					shutdown(sockets[i].fd, SHUT_RDWR);
 					close(sockets[i].fd);
@@ -616,7 +732,13 @@ after_select(fd_set *readset, fd_set *writeset)
 				buffer_consume(&sockets[i].output, len);
 			}
 			if (FD_ISSET(sockets[i].fd, readset)) {
-				len = read(sockets[i].fd, buf, sizeof(buf));
+				do {
+					len = read(sockets[i].fd, buf, sizeof(buf));
+					if (len == -1 && (errno == EAGAIN ||
+					    errno == EINTR))
+						continue;
+					break;
+				} while (1);
 				if (len <= 0) {
 					shutdown(sockets[i].fd, SHUT_RDWR);
 					close(sockets[i].fd);
@@ -634,60 +756,82 @@ after_select(fd_set *readset, fd_set *writeset)
 		}
 }
 
-void
-check_parent_exists(int sig)
+static void
+cleanup_socket(void *p)
 {
-	if (parent_pid != -1 && kill(parent_pid, 0) < 0) {
-		/* printf("Parent has died - Authentication agent exiting.\n"); */
-		exit(1);
-	}
-	signal(SIGALRM, check_parent_exists);
-	alarm(10);
+	if (socket_name[0])
+		unlink(socket_name);
+	if (socket_dir[0])
+		rmdir(socket_dir);
 }
 
-void
-cleanup_socket(void)
+static void
+cleanup_exit(int i)
 {
-	unlink(socket_name);
-	rmdir(socket_dir);
+	cleanup_socket(NULL);
+	exit(i);
 }
 
-void
-cleanup_exit(int i)
+static void
+cleanup_handler(int sig)
 {
-	cleanup_socket();
-	exit(i);
+	cleanup_socket(NULL);
+	_exit(2);
+}
+
+static void
+check_parent_exists(int sig)
+{
+	int save_errno = errno;
+
+	if (parent_pid != -1 && kill(parent_pid, 0) < 0) {
+		/* printf("Parent has died - Authentication agent exiting.\n"); */
+		cleanup_handler(sig); /* safe */
+	}
+	signal(SIGALRM, check_parent_exists);
+	alarm(10);
+	errno = save_errno;
 }
 
-void
-usage()
+static void
+usage(void)
 {
-	fprintf(stderr, "ssh-agent version %s\n", SSH_VERSION);
-	fprintf(stderr, "Usage: %s [-c | -s] [-k] [command {args...]]\n",
-		__progname);
+	fprintf(stderr, "Usage: %s [options] [command [args ...]]\n",
+	    __progname);
+	fprintf(stderr, "Options:\n");
+	fprintf(stderr, "  -c          Generate C-shell commands on stdout.\n");
+	fprintf(stderr, "  -s          Generate Bourne shell commands on stdout.\n");
+	fprintf(stderr, "  -k          Kill the current agent.\n");
+	fprintf(stderr, "  -d          Debug mode.\n");
 	exit(1);
 }
 
 int
 main(int ac, char **av)
 {
-	fd_set readset, writeset;
-	int sock, c_flag = 0, k_flag = 0, s_flag = 0, ch;
+	int sock, c_flag = 0, d_flag = 0, k_flag = 0, s_flag = 0, ch, nalloc;
 	struct sockaddr_un sunaddr;
 #ifdef HAVE_SETRLIMIT
 	struct rlimit rlim;
+#endif
+#ifdef HAVE_CYGWIN
+	int prev_mask;
 #endif
 	pid_t pid;
 	char *shell, *format, *pidstr, pidstrbuf[1 + 3 * sizeof pid];
 	extern int optind;
+	fd_set *readsetp = NULL, *writesetp = NULL;
+
+	SSLeay_add_all_algorithms();
 
 	__progname = get_progname(av[0]);
 	init_rng();
-	
+	seed_rng();
+
 #ifdef __GNU_LIBRARY__
-	while ((ch = getopt(ac, av, "+cks")) != -1) {
+	while ((ch = getopt(ac, av, "+cdks")) != -1) {
 #else /* __GNU_LIBRARY__ */
-	while ((ch = getopt(ac, av, "cks")) != -1) {
+	while ((ch = getopt(ac, av, "cdks")) != -1) {
 #endif /* __GNU_LIBRARY__ */
 		switch (ch) {
 		case 'c':
@@ -703,6 +847,11 @@ main(int ac, char **av)
 				usage();
 			s_flag++;
 			break;
+		case 'd':
+			if (d_flag)
+				usage();
+			d_flag++;
+			break;
 		default:
 			usage();
 		}
@@ -710,10 +859,10 @@ main(int ac, char **av)
 	ac -= optind;
 	av += optind;
 
-	if (ac > 0 && (c_flag || k_flag || s_flag))
+	if (ac > 0 && (c_flag || k_flag || s_flag || d_flag))
 		usage();
 
-	if (ac == 0 && !c_flag && !k_flag && !s_flag) {
+	if (ac == 0 && !c_flag && !s_flag) {
 		shell = getenv("SHELL");
 		if (shell != NULL && strncmp(shell + strlen(shell) - 3, "csh", 3) == 0)
 			c_flag = 1;
@@ -722,14 +871,13 @@ main(int ac, char **av)
 		pidstr = getenv(SSH_AGENTPID_ENV_NAME);
 		if (pidstr == NULL) {
 			fprintf(stderr, "%s not set, cannot kill agent\n",
-				SSH_AGENTPID_ENV_NAME);
+			    SSH_AGENTPID_ENV_NAME);
 			exit(1);
 		}
 		pid = atoi(pidstr);
-		if (pid < 1) {	/* XXX PID_MAX check too */
-		/* Yes, PID_MAX check please */
+		if (pid < 1) {
 			fprintf(stderr, "%s=\"%s\", which is not a good PID\n",
-				SSH_AGENTPID_ENV_NAME, pidstr);
+			    SSH_AGENTPID_ENV_NAME, pidstr);
 			exit(1);
 		}
 		if (kill(pid, SIGTERM) == -1) {
@@ -751,7 +899,7 @@ main(int ac, char **av)
 		exit(1);
 	}
 	snprintf(socket_name, sizeof socket_name, "%s/agent.%d", socket_dir,
-		 parent_pid);
+	    parent_pid);
 
 	/*
 	 * Create socket early so it will exist before command gets run from
@@ -765,22 +913,40 @@ main(int ac, char **av)
 	memset(&sunaddr, 0, sizeof(sunaddr));
 	sunaddr.sun_family = AF_UNIX;
 	strlcpy(sunaddr.sun_path, socket_name, sizeof(sunaddr.sun_path));
+#ifdef HAVE_CYGWIN
+	prev_mask = umask(0177);
+#endif
 	if (bind(sock, (struct sockaddr *) & sunaddr, sizeof(sunaddr)) < 0) {
 		perror("bind");
+#ifdef HAVE_CYGWIN
+		umask(prev_mask);
+#endif
 		cleanup_exit(1);
 	}
+#ifdef HAVE_CYGWIN
+	umask(prev_mask);
+#endif
 	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.
 	 */
+	if (d_flag) {
+		log_init(__progname, SYSLOG_LEVEL_DEBUG1, SYSLOG_FACILITY_AUTH, 1);
+		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("echo Agent pid %d;\n", parent_pid);
+		goto skip;
+	}
 	pid = fork();
 	if (pid == -1) {
 		perror("fork");
-		exit(1);
+		cleanup_exit(1);
 	}
 	if (pid != 0) {		/* Parent - execute the given command. */
 		close(sock);
@@ -788,9 +954,9 @@ main(int ac, char **av)
 		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);
+			    SSH_AUTHSOCKET_ENV_NAME);
 			printf(format, SSH_AGENTPID_ENV_NAME, pidstrbuf,
-			       SSH_AGENTPID_ENV_NAME);
+			    SSH_AGENTPID_ENV_NAME);
 			printf("echo Agent pid %d;\n", pid);
 			exit(0);
 		}
@@ -803,6 +969,15 @@ main(int ac, char **av)
 		perror(av[0]);
 		exit(1);
 	}
+	/* child */
+	log_init(__progname, SYSLOG_LEVEL_INFO, SYSLOG_FACILITY_AUTH, 0);
+
+	if (setsid() == -1) {
+		error("setsid: %s", strerror(errno));
+		cleanup_exit(1);
+	}
+
+	(void)chdir("/");
 	close(0);
 	close(1);
 	close(2);
@@ -811,38 +986,34 @@ main(int ac, char **av)
 	/* deny core dumps, since memory contains unencrypted private keys */
 	rlim.rlim_cur = rlim.rlim_max = 0;
 	if (setrlimit(RLIMIT_CORE, &rlim) < 0) {
-		perror("setrlimit rlimit_core failed");
+		error("setrlimit RLIMIT_CORE: %s", strerror(errno));
 		cleanup_exit(1);
 	}
 #endif
-	if (setsid() == -1) {
-		perror("setsid");
-		cleanup_exit(1);
-	}
-	if (atexit(cleanup_socket) < 0) {
-		perror("atexit");
-		cleanup_exit(1);
-	}
+
+skip:
+	fatal_add_cleanup(cleanup_socket, NULL);
 	new_socket(AUTH_SOCKET, sock);
 	if (ac > 0) {
 		signal(SIGALRM, check_parent_exists);
 		alarm(10);
 	}
 	idtab_init();
-	signal(SIGINT, SIG_IGN);
+	if (!d_flag)
+		signal(SIGINT, SIG_IGN);
 	signal(SIGPIPE, SIG_IGN);
-	signal(SIGHUP, cleanup_exit);
-	signal(SIGTERM, cleanup_exit);
+	signal(SIGHUP, cleanup_handler);
+	signal(SIGTERM, cleanup_handler);
+	nalloc = 0;
+
 	while (1) {
-		FD_ZERO(&readset);
-		FD_ZERO(&writeset);
-		prepare_select(&readset, &writeset);
-		if (select(max_fd + 1, &readset, &writeset, NULL, NULL) < 0) {
+		prepare_select(&readsetp, &writesetp, &max_fd, &nalloc);
+		if (select(max_fd + 1, readsetp, writesetp, NULL, NULL) < 0) {
 			if (errno == EINTR)
 				continue;
-			exit(1);
+			fatal("select: %s", strerror(errno));
 		}
-		after_select(&readset, &writeset);
+		after_select(readsetp, writesetp);
 	}
 	/* NOTREACHED */
 }