269 lines
9.0 KiB
Diff
269 lines
9.0 KiB
Diff
diff -up /dev/null openssh-5.2p1/chrootenv.h
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--- /dev/null 2009-08-19 20:21:50.796466837 +0200
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+++ openssh-5.2p1/chrootenv.h 2009-08-19 23:22:15.000000000 +0200
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@@ -0,0 +1,32 @@
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+/* $OpenBSD: session.h,v 1.30 2008/05/08 12:21:16 djm Exp $ */
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+
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+/*
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+ * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved.
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+ *
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+ * Redistribution and use in source and binary forms, with or without
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+ * modification, are permitted provided that the following conditions
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+ * are met:
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+ * 1. Redistributions of source code must retain the above copyright
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+ * notice, this list of conditions and the following disclaimer.
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+ * 2. Redistributions in binary form must reproduce the above copyright
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+ * notice, this list of conditions and the following disclaimer in the
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+ * documentation and/or other materials provided with the distribution.
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+ *
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+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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+ */
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+#ifndef CHROOTENV_H
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+#define CHROOTENV_H
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+
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+extern int chroot_no_tree;
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+
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+#endif
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+
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diff -up openssh-5.2p1/session.c.homechroot openssh-5.2p1/session.c
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--- openssh-5.2p1/session.c.homechroot 2009-08-19 23:22:14.000000000 +0200
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+++ openssh-5.2p1/session.c 2009-08-19 23:22:15.000000000 +0200
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@@ -119,6 +119,8 @@ void do_child(Session *, const char *);
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void do_motd(void);
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int check_quietlogin(Session *, const char *);
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+int chroot_no_tree = 0;
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+
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static void do_authenticated1(Authctxt *);
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static void do_authenticated2(Authctxt *);
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@@ -802,6 +804,11 @@ do_exec(Session *s, const char *command)
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debug("Forced command (key option) '%.900s'", command);
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}
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+ if ((s->is_subsystem != SUBSYSTEM_INT_SFTP) && chroot_no_tree) {
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+ logit("You aren't welcomed, go away!");
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+ exit (1);
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+ }
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+
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#ifdef SSH_AUDIT_EVENTS
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if (command != NULL)
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PRIVSEP(audit_run_command(command));
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@@ -1399,6 +1406,61 @@ do_nologin(struct passwd *pw)
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}
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/*
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+ * Test if filesystem is mounted nosuid and nodev
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+ */
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+
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+static void
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+test_nosuid (dev_t fs)
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+{
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+ FILE *f;
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+ struct stat st;
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+ char buf[4096], *s, *on, *mountpoint, *opt;
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+ int nodev, nosuid;
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+
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+ if (!(f = popen ("/bin/mount", "r")))
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+ fatal ("%s: popen(\"/bin/mount\", \"r\"): %s",
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+ __func__, strerror (errno));
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+ for (;;) {
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+ s = fgets (buf, sizeof (buf), f);
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+ if (ferror (f))
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+ fatal ("%s: read from popen: %s", __func__,
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+ strerror (errno));
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+ if (!s) {
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+ pclose (f);
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+ fatal ("cannot found filesystem with the chroot directory");
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+ }
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+ (void) strtok (buf, " ");
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+ on = strtok (NULL, " ");
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+ if (strcmp (on, "on")) {
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+ pclose (f);
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+ fatal ("bad format of mount output");
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+ }
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+ mountpoint = strtok (NULL, " ");
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+ if (stat(mountpoint, &st) != 0) {
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+ pclose (f);
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+ fatal("%s: stat(\"%s\"): %s", __func__,
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+ mountpoint, strerror(errno));
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+ }
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+ if (fs != st.st_dev)
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+ continue;
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+ nodev = nosuid = 0;
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+ for (opt = strtok (NULL, "("); opt; opt = strtok (NULL, " ,)")) {
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+ if (!strcmp (opt, "nodev"))
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+ nodev = 1;
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+ else if (!strcmp (opt, "nosuid"))
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+ nosuid = 1;
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+ else if (!strcmp (opt, "noexec"))
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+ nosuid = 1;
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+ if (nodev && nosuid) {
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+ pclose (f);
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+ return;
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+ }
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+ }
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+ fatal ("chroot into directory without nodev or nosuid");
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+ }
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+}
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+
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+/*
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* Chroot into a directory after checking it for safety: all path components
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* must be root-owned directories with strict permissions.
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*/
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@@ -1408,6 +1470,7 @@ safely_chroot(const char *path, uid_t ui
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const char *cp;
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char component[MAXPATHLEN];
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struct stat st;
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+ int last;
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if (*path != '/')
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fatal("chroot path does not begin at root");
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@@ -1419,7 +1482,7 @@ safely_chroot(const char *path, uid_t ui
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* root-owned directory with strict permissions.
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*/
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for (cp = path; cp != NULL;) {
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- if ((cp = strchr(cp, '/')) == NULL)
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+ if (((last = ((cp = strchr(cp, '/')) == NULL))))
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strlcpy(component, path, sizeof(component));
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else {
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cp++;
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@@ -1432,14 +1495,20 @@ safely_chroot(const char *path, uid_t ui
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if (stat(component, &st) != 0)
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fatal("%s: stat(\"%s\"): %s", __func__,
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component, strerror(errno));
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- if (st.st_uid != 0 || (st.st_mode & 022) != 0)
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+ if ((st.st_uid != 0 || (st.st_mode & 022) != 0) && !(last && st.st_uid == uid))
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fatal("bad ownership or modes for chroot "
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"directory %s\"%s\"",
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cp == NULL ? "" : "component ", component);
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if (!S_ISDIR(st.st_mode))
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fatal("chroot path %s\"%s\" is not a directory",
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cp == NULL ? "" : "component ", component);
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+ }
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+ setenv ("TZ", "/etc/localtime", 0);
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+ tzset ();
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+ if (st.st_uid) {
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+ test_nosuid (st.st_dev);
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+ ++chroot_no_tree;
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}
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if (chdir(path) == -1)
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@@ -1451,6 +1520,10 @@ safely_chroot(const char *path, uid_t ui
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if (chdir("/") == -1)
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fatal("%s: chdir(/) after chroot: %s",
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__func__, strerror(errno));
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+
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+ if (access ("/etc/localtime", R_OK) < 0)
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+ ++chroot_no_tree;
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+
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verbose("Changed root directory to \"%s\"", path);
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}
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diff -up openssh-5.2p1/sftp.c.homechroot openssh-5.2p1/sftp.c
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--- openssh-5.2p1/sftp.c.homechroot 2009-02-14 06:26:19.000000000 +0100
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+++ openssh-5.2p1/sftp.c 2009-08-19 23:22:15.000000000 +0200
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@@ -94,6 +94,8 @@ int remote_glob(struct sftp_conn *, cons
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extern char *__progname;
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+int chroot_no_tree = 0;
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+
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/* Separators for interactive commands */
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#define WHITESPACE " \t\r\n"
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diff -up openssh-5.2p1/sftp-common.c.homechroot openssh-5.2p1/sftp-common.c
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--- openssh-5.2p1/sftp-common.c.homechroot 2006-08-05 04:39:40.000000000 +0200
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+++ openssh-5.2p1/sftp-common.c 2009-08-19 23:22:15.000000000 +0200
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@@ -40,6 +40,7 @@
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#include "xmalloc.h"
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#include "buffer.h"
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#include "log.h"
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+#include "chrootenv.h"
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#include "sftp.h"
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#include "sftp-common.h"
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@@ -194,13 +195,13 @@ ls_file(const char *name, const struct s
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char buf[1024], mode[11+1], tbuf[12+1], ubuf[11+1], gbuf[11+1];
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strmode(st->st_mode, mode);
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- if (!remote && (pw = getpwuid(st->st_uid)) != NULL) {
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+ if (!remote && !chroot_no_tree && (pw = getpwuid(st->st_uid)) != NULL) {
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user = pw->pw_name;
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} else {
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snprintf(ubuf, sizeof ubuf, "%u", (u_int)st->st_uid);
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user = ubuf;
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}
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- if (!remote && (gr = getgrgid(st->st_gid)) != NULL) {
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+ if (!remote && !chroot_no_tree && (gr = getgrgid(st->st_gid)) != NULL) {
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group = gr->gr_name;
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} else {
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snprintf(gbuf, sizeof gbuf, "%u", (u_int)st->st_gid);
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diff -up openssh-5.2p1/sftp-server-main.c.homechroot openssh-5.2p1/sftp-server-main.c
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--- openssh-5.2p1/sftp-server-main.c.homechroot 2009-02-21 22:47:02.000000000 +0100
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+++ openssh-5.2p1/sftp-server-main.c 2009-08-19 23:22:15.000000000 +0200
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@@ -22,11 +22,14 @@
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#include <stdarg.h>
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#include <stdio.h>
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#include <unistd.h>
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+#include <time.h>
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#include "log.h"
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#include "sftp.h"
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#include "misc.h"
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+int chroot_no_tree = 0;
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+
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void
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cleanup_exit(int i)
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{
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diff -up openssh-5.2p1/sshd_config.0.homechroot openssh-5.2p1/sshd_config.0
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--- openssh-5.2p1/sshd_config.0.homechroot 2009-08-19 23:22:14.000000000 +0200
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+++ openssh-5.2p1/sshd_config.0 2009-08-19 23:31:26.000000000 +0200
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@@ -112,6 +112,14 @@ DESCRIPTION
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essary if the in-process sftp server is used (see Subsystem for
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details).
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+ In the special case when only sftp is used, not ssh nor scp, it
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+ is possible to use ChrootDirectory %h or ChrootDirectory
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+ /some/path/%u. The file system containing this directory must be
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+ mounted with options nodev and either nosuid or noexec. The owner
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+ of the directory should be the user. The ownership of the other
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+ components of the path must fulfill the usual conditions. No adi-
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+ tional files are required to be present in the directory.
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+
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The default is not to chroot(2).
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Ciphers
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diff -up openssh-5.2p1/sshd_config.5.homechroot openssh-5.2p1/sshd_config.5
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--- openssh-5.2p1/sshd_config.5.homechroot 2009-08-19 23:22:14.000000000 +0200
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+++ openssh-5.2p1/sshd_config.5 2009-08-19 23:22:15.000000000 +0200
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@@ -219,6 +219,17 @@ in-process sftp server is used (see
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.Cm Subsystem
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for details).
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.Pp
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+In the special case when only sftp is used, not ssh nor scp,
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+it is possible to use
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+.Cm ChrootDirectory
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+%h or
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+.Cm ChrootDirectory
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+/some/path/%u. The file system containing this directory must be
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+mounted with options nodev and either nosuid or noexec. The owner of the
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+directory should be the user. The ownership of the other components of the path
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+must fulfill the usual conditions. No aditional files are required to be present
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+in the directory.
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+.Pp
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The default is not to
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.Xr chroot 2 .
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.It Cm Ciphers
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