X-Git-Url: http://andersk.mit.edu/gitweb/openssh.git/blobdiff_plain/1f143cf29a126c4649220cb0bdd033ca0fbe0f75..HEAD:/ssh-keysign.c

diff --git a/ssh-keysign.c b/ssh-keysign.c
index 52092782..0fdcebbd 100644
--- a/ssh-keysign.c
+++ b/ssh-keysign.c
@@ -1,3 +1,4 @@
+/* $OpenBSD: ssh-keysign.c,v 1.30 2010/01/13 01:20:20 dtucker Exp $ */
 /*
  * Copyright (c) 2002 Markus Friedl.  All rights reserved.
  *
@@ -21,35 +22,48 @@
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
+
 #include "includes.h"
-RCSID("$OpenBSD: ssh-keysign.c,v 1.3 2002/06/08 05:07:09 markus Exp $");
+
+#include <fcntl.h>
+#ifdef HAVE_PATHS_H
+#include <paths.h>
+#endif
+#include <pwd.h>
+#include <stdarg.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
 
 #include <openssl/evp.h>
+#include <openssl/rand.h>
+#include <openssl/rsa.h>
 
+#include "xmalloc.h"
 #include "log.h"
 #include "key.h"
+#include "ssh.h"
 #include "ssh2.h"
 #include "misc.h"
-#include "xmalloc.h"
 #include "buffer.h"
-#include "bufaux.h"
 #include "authfile.h"
 #include "msg.h"
 #include "canohost.h"
 #include "pathnames.h"
+#include "readconf.h"
+#include "uidswap.h"
+
+/* XXX readconf.c needs these */
+uid_t original_real_uid;
 
-#ifdef HAVE___PROGNAME
 extern char *__progname;
-#else
-char *__progname;
-#endif
 
 static int
 valid_request(struct passwd *pw, char *host, Key **ret, u_char *data,
     u_int datalen)
 {
 	Buffer b;
-	Key *key;
+	Key *key = NULL;
 	u_char *pkblob;
 	u_int blen, len;
 	char *pkalg, *p;
@@ -59,10 +73,10 @@ valid_request(struct passwd *pw, char *host, Key **ret, u_char *data,
 
 	buffer_init(&b);
 	buffer_append(&b, data, datalen);
- 
-	/* session id, currently limited to SHA1 (20 bytes) */
+
+	/* session id, currently limited to SHA1 (20 bytes) or SHA256 (32) */
 	p = buffer_get_string(&b, &len);
-	if (len != 20)
+	if (len != 20 && len != 32)
 		fail++;
 	xfree(p);
 
@@ -104,9 +118,9 @@ valid_request(struct passwd *pw, char *host, Key **ret, u_char *data,
 	if (strlen(host) != len - 1)
 		fail++;
 	else if (p[len - 1] != '.')
-	      fail++;
+		fail++;
 	else if (strncasecmp(host, p, len - 1) != 0)
-	      fail++;
+		fail++;
 	xfree(p);
 
 	/* local user */
@@ -119,6 +133,7 @@ valid_request(struct passwd *pw, char *host, Key **ret, u_char *data,
 	/* end of message */
 	if (buffer_len(&b) != 0)
 		fail++;
+	buffer_free(&b);
 
 	debug3("valid_request: fail %d", fail);
 
@@ -134,18 +149,31 @@ int
 main(int argc, char **argv)
 {
 	Buffer b;
-	Key *keys[2], *key;
+	Options options;
+	Key *keys[2], *key = NULL;
 	struct passwd *pw;
 	int key_fd[2], i, found, version = 2, fd;
 	u_char *signature, *data;
 	char *host;
 	u_int slen, dlen;
+	u_int32_t rnd[256];
+
+	/* Ensure that stdin and stdout are connected */
+	if ((fd = open(_PATH_DEVNULL, O_RDWR)) < 2)
+		exit(1);
+	/* Leave /dev/null fd iff it is attached to stderr */
+	if (fd > 2)
+		close(fd);
 
 	key_fd[0] = open(_PATH_HOST_RSA_KEY_FILE, O_RDONLY);
 	key_fd[1] = open(_PATH_HOST_DSA_KEY_FILE, O_RDONLY);
 
-	seteuid(getuid());
-	setuid(getuid());
+	original_real_uid = getuid();	/* XXX readconf.c needs this */
+	if ((pw = getpwuid(original_real_uid)) == NULL)
+		fatal("getpwuid failed");
+	pw = pwcopy(pw);
+
+	permanently_set_uid(pw);
 
 	init_rng();
 	seed_rng();
@@ -153,16 +181,23 @@ main(int argc, char **argv)
 
 #ifdef DEBUG_SSH_KEYSIGN
 	log_init("ssh-keysign", SYSLOG_LEVEL_DEBUG3, SYSLOG_FACILITY_AUTH, 0);
-#endif  
+#endif
+
+	/* verify that ssh-keysign is enabled by the admin */
+	initialize_options(&options);
+	(void)read_config_file(_PATH_HOST_CONFIG_FILE, "", &options, 0);
+	fill_default_options(&options);
+	if (options.enable_ssh_keysign != 1)
+		fatal("ssh-keysign not enabled in %s",
+		    _PATH_HOST_CONFIG_FILE);
 
 	if (key_fd[0] == -1 && key_fd[1] == -1)
 		fatal("could not open any host key");
 
-	if ((pw = getpwuid(getuid())) == NULL)
-		fatal("getpwuid failed");
-	pw = pwcopy(pw); 
-
 	SSLeay_add_all_algorithms();
+	for (i = 0; i < 256; i++)
+		rnd[i] = arc4random();
+	RAND_seed(rnd, sizeof(rnd));
 
 	found = 0;
 	for (i = 0; i < 2; i++) {
@@ -179,20 +214,19 @@ main(int argc, char **argv)
 		fatal("no hostkey found");
 
 	buffer_init(&b);
-	if (msg_recv(STDIN_FILENO, &b) < 0)
-		fatal("msg_recv failed");
+	if (ssh_msg_recv(STDIN_FILENO, &b) < 0)
+		fatal("ssh_msg_recv failed");
 	if (buffer_get_char(&b) != version)
 		fatal("bad version");
 	fd = buffer_get_int(&b);
 	if ((fd == STDIN_FILENO) || (fd == STDOUT_FILENO))
 		fatal("bad fd");
 	if ((host = get_local_name(fd)) == NULL)
-		fatal("cannot get sockname for fd");
-	
+		fatal("cannot get local name for fd");
+
 	data = buffer_get_string(&b, &dlen);
 	if (valid_request(pw, host, &key, data, dlen) < 0)
 		fatal("not a valid request");
-	xfree(data);
 	xfree(host);
 
 	found = 0;
@@ -208,11 +242,13 @@ main(int argc, char **argv)
 
 	if (key_sign(keys[i], &signature, &slen, data, dlen) != 0)
 		fatal("key_sign failed");
-	
+	xfree(data);
+
 	/* send reply */
 	buffer_clear(&b);
 	buffer_put_string(&b, signature, slen);
-	msg_send(STDOUT_FILENO, version, &b);
+	if (ssh_msg_send(STDOUT_FILENO, version, &b) == -1)
+		fatal("ssh_msg_send failed");
 
 	return (0);
 }