56e0af8154
temporarily downgrading to 7.2p2 to run tests on additional 7.2p2 patches OBS-URL: https://build.opensuse.org/request/show/547144 OBS-URL: https://build.opensuse.org/package/show/network/openssh?expand=0&rev=124
367 lines
11 KiB
Diff
367 lines
11 KiB
Diff
# HG changeset patch
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# Parent fc81df6f2bf393e45e703c89976c3a0fe6e0a273
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run sftp sessions inside a chroot
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diff --git a/openssh-7.2p2/session.c b/openssh-7.2p2/session.c
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--- a/openssh-7.2p2/session.c
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+++ b/openssh-7.2p2/session.c
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@@ -123,16 +123,18 @@ int do_exec(Session *, const char *);
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void do_login(Session *, const char *);
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#ifdef LOGIN_NEEDS_UTMPX
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static void do_pre_login(Session *s);
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#endif
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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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static int session_pty_req(Session *);
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/* import */
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extern ServerOptions options;
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extern char *__progname;
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@@ -838,16 +840,21 @@ do_exec(Session *s, const char *command)
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"subsystem '%.900s'", s->subsys);
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} else if (command == NULL) {
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snprintf(session_type, sizeof(session_type), "shell");
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} else {
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/* NB. we don't log unforced commands to preserve privacy */
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snprintf(session_type, sizeof(session_type), "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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if (s->ttyfd != -1) {
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tty = s->tty;
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if (strncmp(tty, "/dev/", 5) == 0)
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tty += 5;
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}
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verbose("Starting session: %s%s%s for %s from %.200s port %d id %d",
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session_type,
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@@ -1492,58 +1499,123 @@ do_nologin(struct passwd *pw)
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while (fgets(buf, sizeof(buf), f))
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fputs(buf, stderr);
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fclose(f);
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}
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exit(254);
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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 (char * path, 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 find 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 (memcmp (path, mountpoint, strlen (mountpoint)))
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+ continue;
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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 and either noexec 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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static void
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safely_chroot(const char *path, uid_t uid)
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{
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const char *cp;
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char component[PATH_MAX];
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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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if (strlen(path) >= sizeof(component))
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fatal("chroot path too long");
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/*
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* Descend the path, checking that each component is a
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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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memcpy(component, path, cp - path);
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component[cp - path] = '\0';
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}
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debug3("%s: checking '%s'", __func__, component);
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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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+
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+ if (st.st_uid) {
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+ test_nosuid(path, 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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fatal("Unable to chdir to chroot path \"%s\": "
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"%s", path, strerror(errno));
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if (chroot(path) == -1)
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fatal("chroot(\"%s\"): %s", path, strerror(errno));
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if (chdir("/") == -1)
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fatal("%s: chdir(/) after chroot: %s",
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diff --git a/openssh-7.2p2/sftp-chrootenv.h b/openssh-7.2p2/sftp-chrootenv.h
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new file mode 100644
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--- /dev/null
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+++ b/openssh-7.2p2/sftp-chrootenv.h
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@@ -0,0 +1,30 @@
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+/*
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+ * Copyright (c) 2009 Jan F Chadima. 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 --git a/openssh-7.2p2/sftp-common.c b/openssh-7.2p2/sftp-common.c
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--- a/openssh-7.2p2/sftp-common.c
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+++ b/openssh-7.2p2/sftp-common.c
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@@ -43,16 +43,17 @@
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#include "xmalloc.h"
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#include "ssherr.h"
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#include "sshbuf.h"
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#include "log.h"
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#include "sftp.h"
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#include "sftp-common.h"
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+#include "sftp-chrootenv.h"
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/* Clear contents of attributes structure */
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void
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attrib_clear(Attrib *a)
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{
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a->flags = 0;
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a->size = 0;
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a->uid = 0;
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@@ -216,23 +217,23 @@ ls_file(const char *name, const struct s
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int ulen, glen, sz = 0;
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struct tm *ltime = localtime(&st->st_mtime);
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char *user, *group;
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char buf[1024], mode[11+1], tbuf[12+1], ubuf[11+1], gbuf[11+1];
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char sbuf[FMT_SCALED_STRSIZE];
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time_t now;
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strmode(st->st_mode, mode);
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- if (!remote) {
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+ if (!remote && !chroot_no_tree) {
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user = user_from_uid(st->st_uid, 0);
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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) {
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+ if (!remote && !chroot_no_tree) {
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group = group_from_gid(st->st_gid, 0);
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} else {
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snprintf(gbuf, sizeof gbuf, "%u", (u_int)st->st_gid);
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group = gbuf;
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}
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if (ltime != NULL) {
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now = time(NULL);
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if (now - (365*24*60*60)/2 < st->st_mtime &&
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diff --git a/openssh-7.2p2/sftp-server-main.c b/openssh-7.2p2/sftp-server-main.c
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--- a/openssh-7.2p2/sftp-server-main.c
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+++ b/openssh-7.2p2/sftp-server-main.c
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@@ -17,22 +17,25 @@
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#include "includes.h"
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#include <sys/types.h>
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#include <pwd.h>
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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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#include "xmalloc.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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sftp_server_cleanup_exit(i);
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}
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int
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main(int argc, char **argv)
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diff --git a/openssh-7.2p2/sftp.c b/openssh-7.2p2/sftp.c
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--- a/openssh-7.2p2/sftp.c
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+++ b/openssh-7.2p2/sftp.c
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@@ -112,16 +112,18 @@ struct complete_ctx {
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char **remote_pathp;
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};
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int remote_glob(struct sftp_conn *, const char *, int,
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int (*)(const char *, int), glob_t *); /* proto for sftp-glob.c */
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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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/* ls flags */
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#define LS_LONG_VIEW 0x0001 /* Full view ala ls -l */
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#define LS_SHORT_VIEW 0x0002 /* Single row view ala ls -1 */
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#define LS_NUMERIC_VIEW 0x0004 /* Long view with numeric uid/gid */
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#define LS_NAME_SORT 0x0008 /* Sort by name (default) */
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diff --git a/openssh-7.2p2/sshd_config.0 b/openssh-7.2p2/sshd_config.0
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--- a/openssh-7.2p2/sshd_config.0
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+++ b/openssh-7.2p2/sshd_config.0
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@@ -251,16 +251,24 @@ DESCRIPTION
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directory on some operating systems (see sftp-server(8) for
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details).
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For safety, it is very important that the directory hierarchy be
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prevented from modification by other processes on the system
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(especially those outside the jail). Misconfiguration can lead
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to unsafe environments which sshd(8) cannot detect.
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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 M-bM-^@M-^\noneM-bM-^@M-^], indicating not to chroot(2).
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Ciphers
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Specifies the ciphers allowed. Multiple ciphers must be comma-
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separated. If the specified value begins with a M-bM-^@M-^X+M-bM-^@M-^Y character,
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then the specified ciphers will be appended to the default set
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instead of replacing them.
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diff --git a/openssh-7.2p2/sshd_config.5 b/openssh-7.2p2/sshd_config.5
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--- a/openssh-7.2p2/sshd_config.5
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+++ b/openssh-7.2p2/sshd_config.5
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@@ -424,16 +424,27 @@ for details).
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.Pp
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For safety, it is very important that the directory hierarchy be
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prevented from modification by other processes on the system (especially
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those outside the jail).
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Misconfiguration can lead to unsafe environments which
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.Xr sshd 8
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cannot detect.
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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
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.Dq none ,
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indicating not to
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.Xr chroot 2 .
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.It Cm Ciphers
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Specifies the ciphers allowed.
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Multiple ciphers must be comma-separated.
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If the specified value begins with a
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