http://sourceware.org/ml/gdb-patches/2012-03/msg00171.html
Subject: [patch 3/3] attach-fail-reasons: SELinux deny_ptrace
Hi,
and here is the last bit for new SELinux 'deny_ptrace':
https://bugzilla.redhat.com/show_bug.cgi?id=786878
As even PTRACE_TRACEME fails in such case it needs to install hook for even
that event.
Thanks,
Jan
gdb/
2012-03-06 Jan Kratochvil <jan.kratochvil@redhat.com>
* common/linux-ptrace.c [HAVE_SELINUX_SELINUX_H]: include
selinux/selinux.h.
(linux_ptrace_attach_warnings): Call linux_ptrace_create_warnings.
(linux_ptrace_create_warnings): New.
* common/linux-ptrace.h (linux_ptrace_create_warnings): New declaration.
* config.in: Regenerate.
* configure: Regenerate.
* configure.ac: Check selinux/selinux.h and the selinux library.
* inf-ptrace.c (inf_ptrace_me): Check the ptrace result.
* linux-nat.c (linux_nat_create_inferior): New variable ex. Wrap
to_create_inferior into TRY_CATCH, call linux_ptrace_create_warnings.
gdb/gdbserver/
* config.in: Regenerate.
* configure: Regenerate.
* configure.ac: Check selinux/selinux.h and the selinux library.
* linux-low.c (linux_traceme): New function.
(linux_create_inferior, linux_tracefork_child): Call it instead of
direct ptrace.
Index: gdb-7.11.90.20160829/gdb/nat/linux-ptrace.c
===================================================================
--- gdb-7.11.90.20160829.orig/gdb/nat/linux-ptrace.c 2016-08-29 09:35:26.798230659 +0200
+++ gdb-7.11.90.20160829/gdb/nat/linux-ptrace.c 2016-08-29 09:35:43.162384100 +0200
@@ -25,6 +25,10 @@
#include "gdb_ptrace.h"
#include <sys/procfs.h>
+#ifdef HAVE_SELINUX_SELINUX_H
+# include <selinux/selinux.h>
+#endif /* HAVE_SELINUX_SELINUX_H */
+
/* Stores the ptrace options supported by the running kernel.
A value of -1 means we did not check for features yet. A value
of 0 means there are no supported features. */
@@ -49,6 +53,8 @@
buffer_xml_printf (buffer, _("process %d is a zombie "
"- the process has already terminated"),
(int) pid);
+
+ linux_ptrace_create_warnings (buffer);
}
/* See linux-ptrace.h. */
@@ -592,6 +598,22 @@
linux_ptrace_test_ret_to_nx ();
}
+/* Print all possible reasons we could fail to create a traced process. */
+
+void
+linux_ptrace_create_warnings (struct buffer *buffer)
+{
+#ifdef HAVE_LIBSELINUX
+ /* -1 is returned for errors, 0 if it has no effect, 1 if PTRACE_ATTACH is
+ forbidden. */
+ if (security_get_boolean_active ("deny_ptrace") == 1)
+ buffer_xml_printf (buffer,
+ _("the SELinux boolean 'deny_ptrace' is enabled, "
+ "you can disable this process attach protection by: "
+ "(gdb) shell sudo setsebool deny_ptrace=0"));
+#endif /* HAVE_LIBSELINUX */
+}
+
/* Extract extended ptrace event from wait status. */
int
Index: gdb-7.11.90.20160829/gdb/nat/linux-ptrace.h
===================================================================
--- gdb-7.11.90.20160829.orig/gdb/nat/linux-ptrace.h 2016-08-29 09:35:26.798230659 +0200
+++ gdb-7.11.90.20160829/gdb/nat/linux-ptrace.h 2016-08-29 09:35:43.162384100 +0200
@@ -185,6 +185,7 @@
extern char *linux_ptrace_attach_fail_reason_string (ptid_t ptid, int err);
extern void linux_ptrace_init_warnings (void);
+extern void linux_ptrace_create_warnings (struct buffer *buffer);
extern void linux_check_ptrace_features (void);
extern void linux_enable_event_reporting (pid_t pid, int attached);
extern void linux_disable_event_reporting (pid_t pid);
Index: gdb-7.11.90.20160829/gdb/configure.ac
===================================================================
--- gdb-7.11.90.20160829.orig/gdb/configure.ac 2016-08-29 09:35:26.799230668 +0200
+++ gdb-7.11.90.20160829/gdb/configure.ac 2016-08-29 09:35:43.163384109 +0200
@@ -2108,6 +2108,10 @@
esac
AC_DEFINE_UNQUOTED(GDBINIT,"$gdbinit",[The .gdbinit filename.])
+dnl Check security_get_boolean_active availability.
+AC_CHECK_HEADERS(selinux/selinux.h)
+AC_CHECK_LIB(selinux, security_get_boolean_active)
+
dnl Handle optional features that can be enabled.
# Support for --with-sysroot is a copy of GDB_AC_WITH_DIR,
Index: gdb-7.11.90.20160829/gdb/gdbserver/configure.ac
===================================================================
--- gdb-7.11.90.20160829.orig/gdb/gdbserver/configure.ac 2016-08-29 09:35:26.799230668 +0200
+++ gdb-7.11.90.20160829/gdb/gdbserver/configure.ac 2016-08-29 09:35:43.163384109 +0200
@@ -472,6 +472,10 @@
fi
fi
+dnl Check security_get_boolean_active availability.
+AC_CHECK_HEADERS(selinux/selinux.h)
+AC_CHECK_LIB(selinux, security_get_boolean_active)
+
AC_SUBST(GDBSERVER_DEPFILES)
AC_SUBST(GDBSERVER_LIBS)
AC_SUBST(srv_xmlbuiltin)
Index: gdb-7.11.90.20160829/gdb/gdbserver/linux-low.c
===================================================================
--- gdb-7.11.90.20160829.orig/gdb/gdbserver/linux-low.c 2016-08-29 09:35:26.801230687 +0200
+++ gdb-7.11.90.20160829/gdb/gdbserver/linux-low.c 2016-08-29 09:35:43.165384128 +0200
@@ -933,6 +933,29 @@
return lwp;
}
+/* Execute PTRACE_TRACEME with error checking. */
+
+static void
+linux_traceme (const char *program)
+{
+ int save_errno;
+ struct buffer buffer;
+
+ errno = 0;
+ if (ptrace (PTRACE_TRACEME, 0,
+ (PTRACE_TYPE_ARG3) 0, (PTRACE_TYPE_ARG4) 0) == 0)
+ return;
+
+ save_errno = errno;
+ buffer_init (&buffer);
+ linux_ptrace_create_warnings (&buffer);
+ buffer_grow_str0 (&buffer, "");
+ fprintf (stderr, _("%sCannot trace created process %s: %s.\n"),
+ buffer_finish (&buffer), program, strerror (save_errno));
+ fflush (stderr);
+ _exit (0177);
+}
+
/* Start an inferior process and returns its pid.
ALLARGS is a vector of program-name and args. */
@@ -956,7 +979,7 @@
if (pid == 0)
{
close_most_fds ();
- ptrace (PTRACE_TRACEME, 0, (PTRACE_TYPE_ARG3) 0, (PTRACE_TYPE_ARG4) 0);
+ linux_traceme (program);
setpgid (0, 0);
Index: gdb-7.11.90.20160829/gdb/inf-ptrace.c
===================================================================
--- gdb-7.11.90.20160829.orig/gdb/inf-ptrace.c 2016-08-29 09:35:26.801230687 +0200
+++ gdb-7.11.90.20160829/gdb/inf-ptrace.c 2016-08-29 09:35:43.165384128 +0200
@@ -79,7 +79,15 @@
inf_ptrace_me (void)
{
/* "Trace me, Dr. Memory!" */
+ errno = 0;
ptrace (PT_TRACE_ME, 0, (PTRACE_TYPE_ARG3)0, 0);
+ if (errno != 0)
+ {
+ fprintf_unfiltered (gdb_stderr, _("Cannot create process: %s\n"),
+ safe_strerror (errno));
+ gdb_flush (gdb_stderr);
+ _exit (0177);
+ }
}
/* Start a new inferior Unix child process. EXEC_FILE is the file to
Index: gdb-7.11.90.20160829/gdb/linux-nat.c
===================================================================
--- gdb-7.11.90.20160829.orig/gdb/linux-nat.c 2016-08-29 09:35:26.802230697 +0200
+++ gdb-7.11.90.20160829/gdb/linux-nat.c 2016-08-29 09:35:43.166384137 +0200
@@ -1102,6 +1102,7 @@
{
struct cleanup *restore_personality
= maybe_disable_address_space_randomization (disable_randomization);
+ volatile struct gdb_exception ex;
/* The fork_child mechanism is synchronous and calls target_wait, so
we have to mask the async mode. */
@@ -1109,7 +1110,28 @@
/* Make sure we report all signals during startup. */
linux_nat_pass_signals (ops, 0, NULL);
- linux_ops->to_create_inferior (ops, exec_file, allargs, env, from_tty);
+ TRY
+ {
+ linux_ops->to_create_inferior (ops, exec_file, allargs, env, from_tty);
+ }
+ CATCH (ex, RETURN_MASK_ERROR)
+ {
+ struct buffer buffer;
+ char *message, *buffer_s;
+
+ message = xstrdup (ex.message);
+ make_cleanup (xfree, message);
+
+ buffer_init (&buffer);
+ linux_ptrace_create_warnings (&buffer);
+
+ buffer_grow_str0 (&buffer, "");
+ buffer_s = buffer_finish (&buffer);
+ make_cleanup (xfree, buffer_s);
+
+ throw_error (ex.error, "%s%s", buffer_s, message);
+ }
+ END_CATCH
do_cleanups (restore_personality);
}
Index: gdb-7.11.90.20160829/gdb/config.in
===================================================================
--- gdb-7.11.90.20160829.orig/gdb/config.in 2016-08-29 09:35:26.803230706 +0200
+++ gdb-7.11.90.20160829/gdb/config.in 2016-08-29 09:35:43.166384137 +0200
@@ -267,6 +267,9 @@
/* Define if librpm library is being used. */
#undef HAVE_LIBRPM
+/* Define to 1 if you have the `selinux' library (-lselinux). */
+#undef HAVE_LIBSELINUX
+
/* Define to 1 if you have the <libunwind-ia64.h> header file. */
#undef HAVE_LIBUNWIND_IA64_H
@@ -399,6 +402,9 @@
/* Define to 1 if you have the `scm_new_smob' function. */
#undef HAVE_SCM_NEW_SMOB
+/* Define to 1 if you have the <selinux/selinux.h> header file. */
+#undef HAVE_SELINUX_SELINUX_H
+
/* Define to 1 if you have the `setlocale' function. */
#undef HAVE_SETLOCALE
Index: gdb-7.11.90.20160829/gdb/configure
===================================================================
--- gdb-7.11.90.20160829.orig/gdb/configure 2016-08-29 09:35:26.806230734 +0200
+++ gdb-7.11.90.20160829/gdb/configure 2016-08-29 09:35:43.170384175 +0200
@@ -14642,6 +14642,64 @@
_ACEOF
+for ac_header in selinux/selinux.h
+do :
+ ac_fn_c_check_header_mongrel "$LINENO" "selinux/selinux.h" "ac_cv_header_selinux_selinux_h" "$ac_includes_default"
+if test "x$ac_cv_header_selinux_selinux_h" = x""yes; then :
+ cat >>confdefs.h <<_ACEOF
+#define HAVE_SELINUX_SELINUX_H 1
+_ACEOF
+
+fi
+
+done
+
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for security_get_boolean_active in -lselinux" >&5
+$as_echo_n "checking for security_get_boolean_active in -lselinux... " >&6; }
+if test "${ac_cv_lib_selinux_security_get_boolean_active+set}" = set; then :
+ $as_echo_n "(cached) " >&6
+else
+ ac_check_lib_save_LIBS=$LIBS
+LIBS="-lselinux $LIBS"
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h. */
+
+/* Override any GCC internal prototype to avoid an error.
+ Use char because int might match the return type of a GCC
+ builtin and then its argument prototype would still apply. */
+#ifdef __cplusplus
+extern "C"
+#endif
+char security_get_boolean_active ();
+int
+main ()
+{
+return security_get_boolean_active ();
+ ;
+ return 0;
+}
+_ACEOF
+if ac_fn_c_try_link "$LINENO"; then :
+ ac_cv_lib_selinux_security_get_boolean_active=yes
+else
+ ac_cv_lib_selinux_security_get_boolean_active=no
+fi
+rm -f core conftest.err conftest.$ac_objext \
+ conftest$ac_exeext conftest.$ac_ext
+LIBS=$ac_check_lib_save_LIBS
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_lib_selinux_security_get_boolean_active" >&5
+$as_echo "$ac_cv_lib_selinux_security_get_boolean_active" >&6; }
+if test "x$ac_cv_lib_selinux_security_get_boolean_active" = x""yes; then :
+ cat >>confdefs.h <<_ACEOF
+#define HAVE_LIBSELINUX 1
+_ACEOF
+
+ LIBS="-lselinux $LIBS"
+
+fi
+
+
# Support for --with-sysroot is a copy of GDB_AC_WITH_DIR,
# except that the argument to --with-sysroot is optional.
Index: gdb-7.11.90.20160829/gdb/gdbserver/config.in
===================================================================
--- gdb-7.11.90.20160829.orig/gdb/gdbserver/config.in 2016-08-29 09:35:26.807230743 +0200
+++ gdb-7.11.90.20160829/gdb/gdbserver/config.in 2016-08-29 09:35:43.170384175 +0200
@@ -120,6 +120,9 @@
/* Define to 1 if you have the `mcheck' library (-lmcheck). */
#undef HAVE_LIBMCHECK
+/* Define to 1 if you have the `selinux' library (-lselinux). */
+#undef HAVE_LIBSELINUX
+
/* Define if the target supports branch tracing. */
#undef HAVE_LINUX_BTRACE
@@ -196,6 +199,9 @@
/* Define to 1 if you have the `pwrite' function. */
#undef HAVE_PWRITE
+/* Define to 1 if you have the <selinux/selinux.h> header file. */
+#undef HAVE_SELINUX_SELINUX_H
+
/* Define to 1 if you have the `setns' function. */
#undef HAVE_SETNS
Index: gdb-7.11.90.20160829/gdb/gdbserver/configure
===================================================================
--- gdb-7.11.90.20160829.orig/gdb/gdbserver/configure 2016-08-29 09:35:26.809230762 +0200
+++ gdb-7.11.90.20160829/gdb/gdbserver/configure 2016-08-29 09:35:43.172384194 +0200
@@ -7561,6 +7561,64 @@
fi
fi
+for ac_header in selinux/selinux.h
+do :
+ ac_fn_c_check_header_mongrel "$LINENO" "selinux/selinux.h" "ac_cv_header_selinux_selinux_h" "$ac_includes_default"
+if test "x$ac_cv_header_selinux_selinux_h" = x""yes; then :
+ cat >>confdefs.h <<_ACEOF
+#define HAVE_SELINUX_SELINUX_H 1
+_ACEOF
+
+fi
+
+done
+
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for security_get_boolean_active in -lselinux" >&5
+$as_echo_n "checking for security_get_boolean_active in -lselinux... " >&6; }
+if test "${ac_cv_lib_selinux_security_get_boolean_active+set}" = set; then :
+ $as_echo_n "(cached) " >&6
+else
+ ac_check_lib_save_LIBS=$LIBS
+LIBS="-lselinux $LIBS"
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h. */
+
+/* Override any GCC internal prototype to avoid an error.
+ Use char because int might match the return type of a GCC
+ builtin and then its argument prototype would still apply. */
+#ifdef __cplusplus
+extern "C"
+#endif
+char security_get_boolean_active ();
+int
+main ()
+{
+return security_get_boolean_active ();
+ ;
+ return 0;
+}
+_ACEOF
+if ac_fn_c_try_link "$LINENO"; then :
+ ac_cv_lib_selinux_security_get_boolean_active=yes
+else
+ ac_cv_lib_selinux_security_get_boolean_active=no
+fi
+rm -f core conftest.err conftest.$ac_objext \
+ conftest$ac_exeext conftest.$ac_ext
+LIBS=$ac_check_lib_save_LIBS
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_lib_selinux_security_get_boolean_active" >&5
+$as_echo "$ac_cv_lib_selinux_security_get_boolean_active" >&6; }
+if test "x$ac_cv_lib_selinux_security_get_boolean_active" = x""yes; then :
+ cat >>confdefs.h <<_ACEOF
+#define HAVE_LIBSELINUX 1
+_ACEOF
+
+ LIBS="-lselinux $LIBS"
+
+fi
+
+