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b4df5eb |
diff --git a/configure.ac b/configure.ac
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b4df5eb |
index aeef42a..d01e67e 100644
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b4df5eb |
--- a/configure.ac
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b4df5eb |
+++ b/configure.ac
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b4df5eb |
@@ -4998,6 +4998,37 @@ if test -n "$conf_lastlog_location"; then
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b4df5eb |
[Define if you want to specify the path to your lastlog file])
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b4df5eb |
fi
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b4df5eb |
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b4df5eb |
+AC_ARG_WITH(libcap-ng,
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b4df5eb |
+ [ --with-libcap-ng=[auto/yes/no] Add Libcap-ng support [default=auto]],,
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b4df5eb |
+ with_libcap_ng=auto)
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b4df5eb |
+
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b4df5eb |
+dnl libcap-ng detection
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b4df5eb |
+if test x$with_libcap_ng = xno ; then
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b4df5eb |
+ have_libcap_ng=no;
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b4df5eb |
+else
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b4df5eb |
+ # Start by checking for header file
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b4df5eb |
+ AC_CHECK_HEADER(cap-ng.h, capng_headers=yes, capng_headers=no)
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b4df5eb |
+
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b4df5eb |
+ # See if we have libcap-ng library
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b4df5eb |
+ AC_CHECK_LIB(cap-ng, capng_clear, CAPNG_LDADD=-lcap-ng,)
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b4df5eb |
+
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b4df5eb |
+ # Check results are usable
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b4df5eb |
+ if test x$with_libcap_ng = xyes -a x$CAPNG_LDADD = x ; then
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b4df5eb |
+ AC_MSG_ERROR(libcap-ng support was requested and the library was not found)
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b4df5eb |
+ fi
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b4df5eb |
+ if test x$CAPNG_LDADD != x -a $capng_headers = no ; then
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b4df5eb |
+ AC_MSG_ERROR(libcap-ng libraries found but headers are missing)
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b4df5eb |
+ fi
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b4df5eb |
+fi
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b4df5eb |
+AC_MSG_CHECKING(whether to use libcap-ng)
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b4df5eb |
+if test x$CAPNG_LDADD != x ; then
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b4df5eb |
+ AC_DEFINE(HAVE_LIBCAP_NG,1,[libcap-ng support])
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b4df5eb |
+ SSHDLIBS="$SSHDLIBS -lcap-ng"
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b4df5eb |
+ AC_MSG_RESULT(yes)
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b4df5eb |
+else
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b4df5eb |
+ AC_MSG_RESULT(no)
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b4df5eb |
+fi
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b4df5eb |
+
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b4df5eb |
dnl utmp detection
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b4df5eb |
AC_MSG_CHECKING([if your system defines UTMP_FILE])
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b4df5eb |
AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
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b4df5eb |
diff --git a/session.c b/session.c
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b4df5eb |
index 6cfcba4..80d2806 100644
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b4df5eb |
--- a/session.c
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b4df5eb |
+++ b/session.c
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b4df5eb |
@@ -96,6 +96,10 @@
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b4df5eb |
#include "monitor_wrap.h"
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b4df5eb |
#include "sftp.h"
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b4df5eb |
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b4df5eb |
+#ifdef HAVE_LIBCAP_NG
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b4df5eb |
+#include <cap-ng.h>
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b4df5eb |
+#endif
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b4df5eb |
+
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b4df5eb |
#if defined(KRB5) && defined(USE_AFS)
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b4df5eb |
#include <kafs.h>
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b4df5eb |
#endif
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b4df5eb |
@@ -1586,6 +1590,7 @@ void
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b4df5eb |
do_setusercontext(struct passwd *pw)
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b4df5eb |
{
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b4df5eb |
char *chroot_path, *tmp;
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b4df5eb |
+ int dropped_suid = -1;
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b4df5eb |
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b4df5eb |
platform_setusercontext(pw);
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b4df5eb |
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ecc9f8d |
@@ -1619,10 +1624,25 @@ do_setusercontext(struct passwd *pw)
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b4df5eb |
pw->pw_uid);
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b4df5eb |
chroot_path = percent_expand(tmp, "h", pw->pw_dir,
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b4df5eb |
"u", pw->pw_name, (char *)NULL);
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b4df5eb |
+#ifdef HAVE_LIBCAP_NG
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b4df5eb |
+ /* drop suid soon, retain SYS_CHROOT capability */
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b4df5eb |
+ capng_clear(CAPNG_SELECT_BOTH);
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b4df5eb |
+ capng_update(CAPNG_ADD, CAPNG_EFFECTIVE|CAPNG_PERMITTED, CAP_SYS_CHROOT);
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ecc9f8d |
+ if (pw->pw_uid != 0 &&
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ecc9f8d |
+ (dropped_suid = capng_change_id(pw->pw_uid, pw->pw_gid, CAPNG_INIT_SUPP_GRP)) != 0)
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b4df5eb |
+ logit("capng_change_id() = %d (failure): Try to drop UID later", dropped_suid);
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b4df5eb |
+#endif
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b4df5eb |
#ifdef WITH_SELINUX
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b4df5eb |
sshd_selinux_copy_context();
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b4df5eb |
#endif
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b4df5eb |
safely_chroot(chroot_path, pw->pw_uid);
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b4df5eb |
+#ifdef HAVE_LIBCAP_NG
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b4df5eb |
+ /* Drop chroot capability. Already used */
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b4df5eb |
+ if (dropped_suid == 0) {
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b4df5eb |
+ capng_clear(CAPNG_SELECT_BOTH);
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b4df5eb |
+ capng_apply(CAPNG_SELECT_BOTH);
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b4df5eb |
+ }
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b4df5eb |
+#endif
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b4df5eb |
free(tmp);
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b4df5eb |
free(chroot_path);
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b4df5eb |
/* Make sure we don't attempt to chroot again */
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b4df5eb |
@@ -1654,8 +1673,9 @@ do_setusercontext(struct passwd *pw)
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b4df5eb |
if (!in_chroot && set_id(pw->pw_name) != 0)
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b4df5eb |
fatal("set_id(%s) Failed", pw->pw_name);
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b4df5eb |
# endif /* USE_LIBIAF */
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b4df5eb |
- /* Permanently switch to the desired uid. */
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b4df5eb |
- permanently_set_uid(pw);
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b4df5eb |
+ /* Permanently switch to the desired uid if not yet done. */
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b4df5eb |
+ if (dropped_suid != 0)
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b4df5eb |
+ permanently_set_uid(pw);
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b4df5eb |
#endif
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b4df5eb |
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b4df5eb |
#ifdef WITH_SELINUX
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