- markus@cvs.openbsd.org 2008/02/04 21:53:00

[session.c sftp-server.c sftp.h]
     link sftp-server into sshd; feedback and ok djm@

ChangeLog

@@ -68,6 +68,9 @@
      explain how to handle local file names containing colons;
      requested by Tamas TEVESZ
      ok dtucker
+   - markus@cvs.openbsd.org 2008/02/04 21:53:00
+     [session.c sftp-server.c sftp.h]
+     link sftp-server into sshd; feedback and ok djm@
 
 20080119
  - (djm) Silence noice from expr in ssh-copy-id; patch from
@@ -3596,4 +3599,4 @@
    OpenServer 6 and add osr5bigcrypt support so when someone migrates
    passwords between UnixWare and OpenServer they will still work. OK dtucker@
 
-$Id: ChangeLog,v 1.4833 2008/02/10 11:28:45 djm Exp $
+$Id: ChangeLog,v 1.4834 2008/02/10 11:29:40 djm Exp $

session.c

@@ -1,4 +1,4 @@
-/* $OpenBSD: session.c,v 1.224 2007/09/11 15:47:17 gilles Exp $ */
+/* $OpenBSD: session.c,v 1.225 2008/02/04 21:53:00 markus Exp $ */
 /*
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
  *                    All rights reserved
@@ -87,6 +87,7 @@
 #include "session.h"
 #include "kex.h"
 #include "monitor_wrap.h"
+#include "sftp.h"
 
 #if defined(KRB5) && defined(USE_AFS)
 #include <kafs.h>
@@ -132,6 +133,10 @@ const char *original_command = NULL;
 #define MAX_SESSIONS 10
 Session	sessions[MAX_SESSIONS];
 
+#define SUBSYSTEM_NONE		0
+#define SUBSYSTEM_EXT		1
+#define SUBSYSTEM_INT_SFTP	2
+
 #ifdef HAVE_LOGIN_CAP
 login_cap_t *lc;
 #endif
@@ -683,10 +688,14 @@ do_exec(Session *s, const char *command)
 	if (options.adm_forced_command) {
 		original_command = command;
 		command = options.adm_forced_command;
+		if (s->is_subsystem)
+			s->is_subsystem = SUBSYSTEM_EXT;
 		debug("Forced command (config) '%.900s'", command);
 	} else if (forced_command) {
 		original_command = command;
 		command = forced_command;
+		if (s->is_subsystem)
+			s->is_subsystem = SUBSYSTEM_EXT;
 		debug("Forced command (key option) '%.900s'", command);
 	}
 
@@ -1465,12 +1474,13 @@ child_close_fds(void)
  * environment, closing extra file descriptors, setting the user and group
  * ids, and executing the command or shell.
  */
+#define ARGV_MAX 10
 void
 do_child(Session *s, const char *command)
 {
 	extern char **environ;
 	char **env;
-	char *argv[10];
+	char *argv[ARGV_MAX];
 	const char *shell, *shell0, *hostname = NULL;
 	struct passwd *pw = s->pw;
 
@@ -1602,6 +1612,22 @@ do_child(Session *s, const char *command)
 	/* restore SIGPIPE for child */
 	signal(SIGPIPE, SIG_DFL);
 
+	if (s->is_subsystem == SUBSYSTEM_INT_SFTP) {
+		extern int optind, optreset;
+		int i;
+		char *p, *args;
+
+		setproctitle("%s@internal-sftp-server", s->pw->pw_name);
+		args = strdup(command ? command : "sftp-server");
+		for (i = 0, (p = strtok(args, " ")); p; (p = strtok(NULL, " ")))
+			if (i < ARGV_MAX - 1)
+				argv[i++] = p;
+		argv[i] = NULL;
+		optind = optreset = 1;
+		__progname = argv[0];
+		exit(sftp_server_main(i, argv));
+	}
+
 	if (options.use_login) {
 		launch_login(pw, hostname);
 		/* NEVERREACHED */
@@ -1874,13 +1900,16 @@ session_subsystem_req(Session *s)
 		if (strcmp(subsys, options.subsystem_name[i]) == 0) {
 			prog = options.subsystem_command[i];
 			cmd = options.subsystem_args[i];
-			if (stat(prog, &st) < 0) {
+			if (!strcmp("internal-sftp", prog)) {
+				s->is_subsystem = SUBSYSTEM_INT_SFTP;
+			} else if (stat(prog, &st) < 0) {
 				error("subsystem: cannot stat %s: %s", prog,
 				    strerror(errno));
 				break;
+			} else {
+				s->is_subsystem = SUBSYSTEM_EXT;
 			}
 			debug("subsystem: exec() %s", cmd);
-			s->is_subsystem = 1;
 			do_exec(s, cmd);
 			success = 1;
 			break;

sftp-server.c

@@ -1,4 +1,4 @@
-/* $OpenBSD: sftp-server.c,v 1.75 2008/01/21 17:24:30 djm Exp $ */
+/* $OpenBSD: sftp-server.c,v 1.76 2008/02/04 21:53:00 markus Exp $ */
 /*
  * Copyright (c) 2000-2004 Markus Friedl.  All rights reserved.
  *
@@ -1110,7 +1110,7 @@ process(void)
 	if (msg_len > SFTP_MAX_MSG_LENGTH) {
 		error("bad message from %s local user %s",
 		    client_addr, pw->pw_name);
-		cleanup_exit(11);
+		sftp_server_cleanup_exit(11);
 	}
 	if (buf_len < msg_len + 4)
 		return;
@@ -1183,18 +1183,22 @@ process(void)
 		break;
 	}
 	/* discard the remaining bytes from the current packet */
-	if (buf_len < buffer_len(&iqueue))
+	if (buf_len < buffer_len(&iqueue)) {
-		fatal("iqueue grew unexpectedly");
+		error("iqueue grew unexpectedly");
+		sftp_server_cleanup_exit(255);
+	}
 	consumed = buf_len - buffer_len(&iqueue);
-	if (msg_len < consumed)
+	if (msg_len < consumed) {
-		fatal("msg_len %d < consumed %d", msg_len, consumed);
+		error("msg_len %d < consumed %d", msg_len, consumed);
+		sftp_server_cleanup_exit(255);
+	}
 	if (msg_len > consumed)
 		buffer_consume(&iqueue, msg_len - consumed);
 }
 
 /* Cleanup handler that logs active handles upon normal exit */
 void
-cleanup_exit(int i)
+sftp_server_cleanup_exit(int i)
 {
 	if (pw != NULL && client_addr != NULL) {
 		handle_log_exit();
@@ -1205,7 +1209,7 @@ cleanup_exit(int i)
 }
 
 static void
-usage(void)
+sftp_server_usage(void)
 {
 	extern char *__progname;
 
@@ -1215,7 +1219,7 @@ usage(void)
 }
 
 int
-main(int argc, char **argv)
+sftp_server_main(int argc, char **argv)
 {
 	fd_set *rset, *wset;
 	int in, out, max, ch, skipargs = 0, log_stderr = 0;
@@ -1256,7 +1260,7 @@ main(int argc, char **argv)
 			break;
 		case 'h':
 		default:
-			usage();
+			sftp_server_usage();
 		}
 	}
 
@@ -1264,15 +1268,19 @@ main(int argc, char **argv)
 
 	if ((cp = getenv("SSH_CONNECTION")) != NULL) {
 		client_addr = xstrdup(cp);
-		if ((cp = strchr(client_addr, ' ')) == NULL)
+		if ((cp = strchr(client_addr, ' ')) == NULL) {
-			fatal("Malformed SSH_CONNECTION variable: \"%s\"",
+			error("Malformed SSH_CONNECTION variable: \"%s\"",
 			    getenv("SSH_CONNECTION"));
+			sftp_server_cleanup_exit(255);
+		}
 		*cp = '\0';
 	} else
 		client_addr = xstrdup("UNKNOWN");
 
-	if ((pw = getpwuid(getuid())) == NULL)
+	if ((pw = getpwuid(getuid())) == NULL) {
-		fatal("No user found for uid %lu", (u_long)getuid());
+		error("No user found for uid %lu", (u_long)getuid());
+		sftp_server_cleanup_exit(255);
+	}
 	pw = pwcopy(pw);
 
 	logit("session opened for local user %s from [%s]",
@@ -1320,7 +1328,7 @@ main(int argc, char **argv)
 			if (errno == EINTR)
 				continue;
 			error("select: %s", strerror(errno));
-			cleanup_exit(2);
+			sftp_server_cleanup_exit(2);
 		}
 
 		/* copy stdin to iqueue */
@@ -1328,10 +1336,10 @@ main(int argc, char **argv)
 			len = read(in, buf, sizeof buf);
 			if (len == 0) {
 				debug("read eof");
-				cleanup_exit(0);
+				sftp_server_cleanup_exit(0);
 			} else if (len < 0) {
 				error("read: %s", strerror(errno));
-				cleanup_exit(1);
+				sftp_server_cleanup_exit(1);
 			} else {
 				buffer_append(&iqueue, buf, len);
 			}
@@ -1341,7 +1349,7 @@ main(int argc, char **argv)
 			len = write(out, buffer_ptr(&oqueue), olen);
 			if (len < 0) {
 				error("write: %s", strerror(errno));
-				cleanup_exit(1);
+				sftp_server_cleanup_exit(1);
 			} else {
 				buffer_consume(&oqueue, len);
 			}

sftp.h

@@ -1,4 +1,4 @@
-/* $OpenBSD: sftp.h,v 1.5 2006/03/25 22:22:43 djm Exp $ */
+/* $OpenBSD: sftp.h,v 1.6 2008/02/04 21:53:00 markus Exp $ */
 
 /*
  * Copyright (c) 2001 Markus Friedl.  All rights reserved.
@@ -90,3 +90,6 @@
 #define SSH2_FX_CONNECTION_LOST		7
 #define SSH2_FX_OP_UNSUPPORTED		8
 #define SSH2_FX_MAX			8
+
+int	sftp_server_main(int, char **);
+void	sftp_server_cleanup_exit(int) __dead;