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openssh/openssh-6.6p1-sftp_homechroot.patch
Petr Cerny efb05e6527 Accepting request 230097 from home:pcerny:factory 
- Update of the underlying OpenSSH to 6.6p1

- update to 6.6p1
  Security:
  * sshd(8): when using environment passing with a sshd_config(5)
    AcceptEnv pattern with a wildcard. OpenSSH prior to 6.6 could
    be tricked into accepting any enviornment variable that
    contains the characters before the wildcard character.
  Features since 6.5p1:
  * ssh(1), sshd(8): removal of the J-PAKE authentication code,
    which was experimental, never enabled and has been
    unmaintained for some time.
  * ssh(1): skip 'exec' clauses other clauses predicates failed
    to match while processing Match blocks.
  * ssh(1): if hostname canonicalisation is enabled and results
    in the destination hostname being changed, then re-parse
    ssh_config(5) files using the new destination hostname. This
    gives 'Host' and 'Match' directives that use the expanded
    hostname a chance to be applied.
  Bugfixes:
  * ssh(1): avoid spurious "getsockname failed: Bad file
    descriptor" in ssh -W. bz#2200, debian#738692
  * sshd(8): allow the shutdown(2) syscall in seccomp-bpf and
    systrace sandbox modes, as it is reachable if the connection
    is terminated during the pre-auth phase.
  * ssh(1), sshd(8): fix unsigned overflow that in SSH protocol 1
    bignum parsing. Minimum key length checks render this bug
    unexploitable to compromise SSH 1 sessions.
  * sshd_config(5): clarify behaviour of a keyword that appears
    in multiple matching Match blocks. bz#2184

OBS-URL: https://build.opensuse.org/request/show/230097
OBS-URL: https://build.opensuse.org/package/show/network/openssh?expand=0&rev=76
2014-04-14 21:53:01 +00:00

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# run sftp sessions inside a chroot
diff --git a/openssh-6.6p1/session.c b/openssh-6.6p1/session.c
--- a/openssh-6.6p1/session.c
+++ b/openssh-6.6p1/session.c
@@ -120,16 +120,18 @@ int do_exec(Session *, const char *);
void do_login(Session *, const char *);
#ifdef LOGIN_NEEDS_UTMPX
static void do_pre_login(Session *s);
#endif
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 *);
static int session_pty_req(Session *);
/* import */
extern ServerOptions options;
extern char *__progname;
@@ -827,16 +829,21 @@ do_exec(Session *s, const char *command)
"subsystem '%.900s'", s->subsys);
} else if (command == NULL) {
snprintf(session_type, sizeof(session_type), "shell");
} else {
/* NB. we don't log unforced commands to preserve privacy */
snprintf(session_type, sizeof(session_type), "command");
}
+ if ((s->is_subsystem != SUBSYSTEM_INT_SFTP) && chroot_no_tree) {
+ logit("You aren't welcomed, go away!");
+ exit (1);
+ }
+
if (s->ttyfd != -1) {
tty = s->tty;
if (strncmp(tty, "/dev/", 5) == 0)
tty += 5;
}
verbose("Starting session: %s%s%s for %s from %.200s port %d",
session_type,
@@ -1463,67 +1470,132 @@ do_nologin(struct passwd *pw)
while (fgets(buf, sizeof(buf), f))
fputs(buf, stderr);
fclose(f);
}
exit(254);
}
/*
+ * 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 find 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 and either noexec or nosuid");
+ }
+}
+
+/*
* Chroot into a directory after checking it for safety: all path components
* must be root-owned directories with strict permissions.
*/
static void
safely_chroot(const char *path, uid_t uid)
{
const char *cp;
char component[MAXPATHLEN];
struct stat st;
+ int last;
if (*path != '/')
fatal("chroot path does not begin at root");
if (strlen(path) >= sizeof(component))
fatal("chroot path too long");
/*
* Descend the path, checking that each component is a
* 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++;
memcpy(component, path, cp - path);
component[cp - path] = '\0';
}
debug3("%s: checking '%s'", __func__, component);
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)
fatal("Unable to chdir to chroot path \"%s\": "
"%s", path, strerror(errno));
if (chroot(path) == -1)
fatal("chroot(\"%s\"): %s", path, strerror(errno));
if (chdir("/") == -1)
fatal("%s: chdir(/) after chroot: %s",
__func__, strerror(errno));
+
verbose("Changed root directory to \"%s\"", path);
}
/* Set login name, uid, gid, and groups. */
void
do_setusercontext(struct passwd *pw)
{
char *chroot_path, *tmp;
diff --git a/openssh-6.6p1/sftp-chrootenv.h b/openssh-6.6p1/sftp-chrootenv.h
new file mode 100644
--- /dev/null
+++ b/openssh-6.6p1/sftp-chrootenv.h
@@ -0,0 +1,30 @@
+/*
+ * Copyright (c) 2009 Jan F Chadima. 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 --git a/openssh-6.6p1/sftp-common.c b/openssh-6.6p1/sftp-common.c
--- a/openssh-6.6p1/sftp-common.c
+++ b/openssh-6.6p1/sftp-common.c
@@ -42,16 +42,17 @@
#endif
#include "xmalloc.h"
#include "buffer.h"
#include "log.h"
#include "sftp.h"
#include "sftp-common.h"
+#include "sftp-chrootenv.h"
/* Clear contents of attributes structure */
void
attrib_clear(Attrib *a)
{
a->flags = 0;
a->size = 0;
a->uid = 0;
@@ -193,23 +194,23 @@ ls_file(const char *name, const struct s
int ulen, glen, sz = 0;
struct tm *ltime = localtime(&st->st_mtime);
char *user, *group;
char buf[1024], mode[11+1], tbuf[12+1], ubuf[11+1], gbuf[11+1];
char sbuf[FMT_SCALED_STRSIZE];
time_t now;
strmode(st->st_mode, mode);
- if (!remote) {
+ if (!remote && !chroot_no_tree) {
user = user_from_uid(st->st_uid, 0);
} else {
snprintf(ubuf, sizeof ubuf, "%u", (u_int)st->st_uid);
user = ubuf;
}
- if (!remote) {
+ if (!remote && !chroot_no_tree) {
group = group_from_gid(st->st_gid, 0);
} else {
snprintf(gbuf, sizeof gbuf, "%u", (u_int)st->st_gid);
group = gbuf;
}
if (ltime != NULL) {
now = time(NULL);
if (now - (365*24*60*60)/2 < st->st_mtime &&
diff --git a/openssh-6.6p1/sftp-server-main.c b/openssh-6.6p1/sftp-server-main.c
--- a/openssh-6.6p1/sftp-server-main.c
+++ b/openssh-6.6p1/sftp-server-main.c
@@ -17,21 +17,24 @@
#include "includes.h"
#include <sys/types.h>
#include <pwd.h>
#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)
{
sftp_server_cleanup_exit(i);
}
int
main(int argc, char **argv)
diff --git a/openssh-6.6p1/sftp.c b/openssh-6.6p1/sftp.c
--- a/openssh-6.6p1/sftp.c
+++ b/openssh-6.6p1/sftp.c
@@ -109,16 +109,18 @@ struct complete_ctx {
char **remote_pathp;
};
int remote_glob(struct sftp_conn *, const char *, int,
int (*)(const char *, int), glob_t *); /* proto for sftp-glob.c */
extern char *__progname;
+int chroot_no_tree = 0;
+
/* Separators for interactive commands */
#define WHITESPACE " \t\r\n"
/* ls flags */
#define LS_LONG_VIEW 0x0001 /* Full view ala ls -l */
#define LS_SHORT_VIEW 0x0002 /* Single row view ala ls -1 */
#define LS_NUMERIC_VIEW 0x0004 /* Long view with numeric uid/gid */
#define LS_NAME_SORT 0x0008 /* Sort by name (default) */
diff --git a/openssh-6.6p1/sshd_config.0 b/openssh-6.6p1/sshd_config.0
--- a/openssh-6.6p1/sshd_config.0
+++ b/openssh-6.6p1/sshd_config.0
@@ -189,16 +189,24 @@ DESCRIPTION
session this requires at least a shell, typically sh(1), and
basic /dev nodes such as null(4), zero(4), stdin(4), stdout(4),
stderr(4), arandom(4) and tty(4) devices. For file transfer
sessions using ``sftp'', no additional configuration of the
environment is necessary if the in-process sftp server is used,
though sessions which use logging do require /dev/log inside the
chroot directory (see sftp-server(8) 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
Specifies the ciphers allowed for protocol version 2. Multiple
ciphers must be comma-separated. The supported ciphers are:
``3des-cbc'', ``aes128-cbc'', ``aes192-cbc'', ``aes256-cbc'',
``aes128-ctr'', ``aes192-ctr'', ``aes256-ctr'',
diff --git a/openssh-6.6p1/sshd_config.5 b/openssh-6.6p1/sshd_config.5
--- a/openssh-6.6p1/sshd_config.5
+++ b/openssh-6.6p1/sshd_config.5
@@ -324,16 +324,27 @@ For file transfer sessions using
no additional configuration of the environment is necessary if the
in-process sftp server is used,
though sessions which use logging do require
.Pa /dev/log
inside the chroot directory (see
.Xr sftp-server 8
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
Specifies the ciphers allowed for protocol version 2.
Multiple ciphers must be comma-separated.
The supported ciphers are:
.Pp
.Dq 3des-cbc ,
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