diff -up /dev/null openssh-5.2p1/chrootenv.h
--- /dev/null 2009-08-19 20:21:50.796466837 +0200
+++ openssh-5.2p1/chrootenv.h 2009-08-19 23:22:15.000000000 +0200
@@ -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
+
diff -up openssh-5.2p1/session.c.homechroot openssh-5.2p1/session.c
--- openssh-5.2p1/session.c.homechroot 2009-08-19 23:22:14.000000000 +0200
+++ openssh-5.2p1/session.c 2009-08-19 23:22:15.000000000 +0200
@@ -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 +1406,61 @@ do_nologin(struct passwd *pw)
}
/*
+ * Test if filesystem is mounted nosuid and nodev
+ */
+
+static void
+test_nosuid (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 (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 +1470,7 @@ 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 +1482,7 @@ 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 +1495,20 @@ 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 (st.st_dev);
+ ++chroot_no_tree;
}
if (chdir(path) == -1)
@@ -1451,6 +1520,10 @@ 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);
}
diff -up openssh-5.2p1/sftp.c.homechroot openssh-5.2p1/sftp.c
--- openssh-5.2p1/sftp.c.homechroot 2009-02-14 06:26:19.000000000 +0100
+++ openssh-5.2p1/sftp.c 2009-08-19 23:22:15.000000000 +0200
@@ -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"
diff -up openssh-5.2p1/sftp-common.c.homechroot openssh-5.2p1/sftp-common.c
--- openssh-5.2p1/sftp-common.c.homechroot 2006-08-05 04:39:40.000000000 +0200
+++ openssh-5.2p1/sftp-common.c 2009-08-19 23:22:15.000000000 +0200
@@ -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);
diff -up openssh-5.2p1/sftp-server-main.c.homechroot openssh-5.2p1/sftp-server-main.c
--- openssh-5.2p1/sftp-server-main.c.homechroot 2009-02-21 22:47:02.000000000 +0100
+++ openssh-5.2p1/sftp-server-main.c 2009-08-19 23:22:15.000000000 +0200
@@ -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)
{
diff -up openssh-5.2p1/sshd_config.0.homechroot openssh-5.2p1/sshd_config.0
--- openssh-5.2p1/sshd_config.0.homechroot 2009-08-19 23:22:14.000000000 +0200
+++ openssh-5.2p1/sshd_config.0 2009-08-19 23:31:26.000000000 +0200
@@ -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
diff -up openssh-5.2p1/sshd_config.5.homechroot openssh-5.2p1/sshd_config.5
--- openssh-5.2p1/sshd_config.5.homechroot 2009-08-19 23:22:14.000000000 +0200
+++ openssh-5.2p1/sshd_config.5 2009-08-19 23:22:15.000000000 +0200
@@ -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