File openssh-5.2p1-homechroot.patch of Package openssh

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File openssh-5.2p1-homechroot.patch of Package openssh (Revision 706005ca7aa9f84c4986d460c4b8dbc2)

Currently displaying revision 706005ca7aa9f84c4986d460c4b8dbc2 , Show latest

--- chrootenv.h 
+++ chrootenv.h
@@ -0,0 +1,32 @@
+/* $OpenBSD: session.h,v 1.30 2008/05/08 12:21:16 djm Exp $ */
+
+/*
+ * 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
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+#ifndef CHROOTENV_H
+#define CHROOTENV_H
+
+extern int	chroot_no_tree;
+
+#endif
+
--- session.c
+++ session.c
@@ -119,6 +119,8 @@ void	do_child(Session *, const char *);
 void	do_motd(void);
 int	check_quietlogin(Session *, const char *);
 
+int	chroot_no_tree = 0;
+
 static void do_authenticated1(Authctxt *);
 static void do_authenticated2(Authctxt *);
 
@@ -802,6 +804,11 @@ do_exec(Session *s, const char *command)
 		debug("Forced command (key option) '%.900s'", command);
 	}
 
+	if ((s->is_subsystem != SUBSYSTEM_INT_SFTP) && chroot_no_tree) {
+		logit("You aren't welcomed, go away!");
+		exit (1);
+	}
+
 #ifdef SSH_AUDIT_EVENTS
 	if (command != NULL)
 		PRIVSEP(audit_run_command(command));
@@ -1399,6 +1406,63 @@ do_nologin(struct passwd *pw)
 }
 
 /*
+ * Test if filesystem is mounted nosuid and nodev
+ */
+
+static void
+test_nosuid (char * path, dev_t fs)
+{
+	FILE *f;
+	struct stat st;
+	char buf[4096], *s, *on, *mountpoint, *opt;
+	int nodev, nosuid;
+
+	if (!(f = popen ("/bin/mount", "r")))
+		fatal ("%s: popen(\"/bin/mount\", \"r\"): %s",
+		    __func__, strerror (errno));
+	for (;;) {
+		s = fgets (buf, sizeof (buf), f);
+		if (ferror (f))
+			fatal ("%s: read from popen: %s", __func__,
+			    strerror (errno));
+		if (!s) {
+			pclose (f);
+			fatal ("cannot found filesystem with the chroot directory");
+		}
+		(void) strtok (buf, " ");
+		on = strtok (NULL, " ");
+		if (strcmp (on, "on")) {
+			pclose (f);
+			fatal ("bad format of mount output");
+		}
+		mountpoint = strtok (NULL, " ");
+		if (memcmp (path, mountpoint, strlen (mountpoint)))
+			continue;
+		if (stat(mountpoint, &st) != 0) {
+			pclose (f);
+			fatal("%s: stat(\"%s\"): %s", __func__,
+			    mountpoint, strerror(errno));
+		}
+		if (fs != st.st_dev)
+			continue;
+		nodev = nosuid = 0;
+		for (opt = strtok (NULL, "("); opt; opt = strtok (NULL, " ,)")) {
+			if (!strcmp (opt, "nodev"))
+				nodev = 1;
+			else if (!strcmp (opt, "nosuid"))
+				nosuid = 1;
+			else if (!strcmp (opt, "noexec"))
+				nosuid = 1;
+			if (nodev && nosuid) {
+				pclose (f);
+				return;
+			}
+		}
+		fatal ("chroot into directory without nodev or nosuid");
+	}	
+}
+
+/*
  * Chroot into a directory after checking it for safety: all path components
  * must be root-owned directories with strict permissions.
  */
@@ -1408,6 +1472,7 @@ safely_chroot(const char *path, uid_t ui
 	const char *cp;
 	char component[MAXPATHLEN];
 	struct stat st;
+	int last;
 
 	if (*path != '/')
 		fatal("chroot path does not begin at root");
@@ -1419,7 +1484,7 @@ safely_chroot(const char *path, uid_t ui
 	 * root-owned directory with strict permissions.
 	 */
 	for (cp = path; cp != NULL;) {
-		if ((cp = strchr(cp, '/')) == NULL)
+		if (((last = ((cp = strchr(cp, '/')) == NULL))))
 			strlcpy(component, path, sizeof(component));
 		else {
 			cp++;
@@ -1432,14 +1497,20 @@ safely_chroot(const char *path, uid_t ui
 		if (stat(component, &st) != 0)
 			fatal("%s: stat(\"%s\"): %s", __func__,
 			    component, strerror(errno));
-		if (st.st_uid != 0 || (st.st_mode & 022) != 0)
+		if ((st.st_uid != 0 || (st.st_mode & 022) != 0) && !(last && st.st_uid == uid))
 			fatal("bad ownership or modes for chroot "
 			    "directory %s\"%s\"", 
 			    cp == NULL ? "" : "component ", component);
 		if (!S_ISDIR(st.st_mode))
 			fatal("chroot path %s\"%s\" is not a directory",
 			    cp == NULL ? "" : "component ", component);
+	}
+	setenv ("TZ", "/etc/localtime", 0);
+	tzset ();
 
+	if (st.st_uid) {
+		test_nosuid (path, st.st_dev);
+		++chroot_no_tree;
 	}
 
 	if (chdir(path) == -1)
@@ -1451,6 +1522,10 @@ safely_chroot(const char *path, uid_t ui
 	if (chdir("/") == -1)
 		fatal("%s: chdir(/) after chroot: %s",
 		    __func__, strerror(errno));
+
+	if (access ("/etc/localtime", R_OK) < 0)
+		++chroot_no_tree;
+
 	verbose("Changed root directory to \"%s\"", path);
 }
 
--- sftp.c
+++ sftp.c
@@ -94,6 +94,8 @@ int remote_glob(struct sftp_conn *, cons
 
 extern char *__progname;
 
+int	chroot_no_tree = 0;
+
 /* Separators for interactive commands */
 #define WHITESPACE " \t\r\n"
 
--- sftp-common.c
+++ sftp-common.c
@@ -40,6 +40,7 @@
 #include "xmalloc.h"
 #include "buffer.h"
 #include "log.h"
+#include "chrootenv.h"
 
 #include "sftp.h"
 #include "sftp-common.h"
@@ -194,13 +195,13 @@ ls_file(const char *name, const struct s
 	char buf[1024], mode[11+1], tbuf[12+1], ubuf[11+1], gbuf[11+1];
 
 	strmode(st->st_mode, mode);
-	if (!remote && (pw = getpwuid(st->st_uid)) != NULL) {
+	if (!remote && !chroot_no_tree && (pw = getpwuid(st->st_uid)) != NULL) {
 		user = pw->pw_name;
 	} else {
 		snprintf(ubuf, sizeof ubuf, "%u", (u_int)st->st_uid);
 		user = ubuf;
 	}
-	if (!remote && (gr = getgrgid(st->st_gid)) != NULL) {
+	if (!remote && !chroot_no_tree && (gr = getgrgid(st->st_gid)) != NULL) {
 		group = gr->gr_name;
 	} else {
 		snprintf(gbuf, sizeof gbuf, "%u", (u_int)st->st_gid);
--- sftp-server-main.c
+++ sftp-server-main.c
@@ -22,11 +22,14 @@
 #include <stdarg.h>
 #include <stdio.h>
 #include <unistd.h>
+#include <time.h>
 
 #include "log.h"
 #include "sftp.h"
 #include "misc.h"
 
+int	chroot_no_tree = 0;
+
 void
 cleanup_exit(int i)
 {
--- sshd_config.0
+++ sshd_config.0
@@ -112,6 +112,14 @@ DESCRIPTION
              essary if the in-process sftp server is used (see Subsystem for
              details).
 
+             In the special case when only sftp is used, not ssh nor scp, it
+             is possible to use ChrootDirectory %h or ChrootDirectory
+             /some/path/%u. The file system containing this directory must be
+             mounted with options nodev and either nosuid or noexec. The owner
+             of the directory should be the user. The ownership of the other
+             components of the path must fulfill the usual conditions. No adi-
+             tional files are required to be present in the directory.
+
              The default is not to chroot(2).
 
      Ciphers
--- sshd_config.5
+++ sshd_config.5
@@ -219,6 +219,17 @@ in-process sftp server is used (see
 .Cm Subsystem
 for details).
 .Pp
+In the special case when only sftp is used, not ssh nor scp,
+it is possible to use
+.Cm ChrootDirectory
+%h or
+.Cm ChrootDirectory
+/some/path/%u. The file system containing this directory must be
+mounted with options nodev and either nosuid or noexec. The owner of the 
+directory should be the user. The ownership of the other components of the path
+must fulfill the usual conditions. No aditional files are required to be present
+in the directory.
+.Pp
 The default is not to
 .Xr chroot 2 .
 .It Cm Ciphers

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File openssh-5.2p1-homechroot.patch of Package openssh (Revision 706005ca7aa9f84c4986d460c4b8dbc2)

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