gdb/gdb-attach-fail-reasons-5of5.patch

From FEDORA_PATCHES Mon Sep 17 00:00:00 2001
From: Fedora GDB patches <invalid@email.com>
Date: Fri, 27 Oct 2017 21:07:50 +0200
Subject: attach-fail-reasons: SELinux deny_ptrace

FileName: gdb-attach-fail-reasons-5of5.patch

;; Print reasons for failed attach/spawn incl. SELinux deny_ptrace (BZ 786878).
;;=push+jan

http://sourceware.org/ml/gdb-patches/2012-03/msg00171.html

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.
---
 gdb/config.in              |  6 +++++
 gdb/configure              | 58 ++++++++++++++++++++++++++++++++++++++++++++++
 gdb/configure.ac           |  4 ++++
 gdb/gdbserver/config.in    |  6 +++++
 gdb/gdbserver/configure    | 58 ++++++++++++++++++++++++++++++++++++++++++++++
 gdb/gdbserver/configure.ac |  4 ++++
 gdb/gdbserver/linux-low.c  | 16 ++++++++++++-
 gdb/linux-nat.c            | 24 ++++++++++++++++++-
 gdb/nat/linux-ptrace.c     | 22 ++++++++++++++++++
 gdb/nat/linux-ptrace.h     |  1 +
 10 files changed, 197 insertions(+), 2 deletions(-)

diff --git a/gdb/config.in b/gdb/config.in
index edd7028f76..4de3e842d1 100644
--- a/gdb/config.in
+++ b/gdb/config.in
@@ -270,6 +270,9 @@
 /* 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
 
@@ -393,6 +396,9 @@
 /* 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
 
diff --git a/gdb/configure b/gdb/configure
index 1cecdbc3b5..904cc453ad 100755
--- a/gdb/configure
+++ b/gdb/configure
@@ -15681,6 +15681,64 @@ cat >>confdefs.h <<_ACEOF
 _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.
diff --git a/gdb/configure.ac b/gdb/configure.ac
index e232c1adcb..1557760ed8 100644
--- a/gdb/configure.ac
+++ b/gdb/configure.ac
@@ -2043,6 +2043,10 @@ case $host_os in
 esac
 AC_DEFINE_UNQUOTED(GDBINIT,"$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,
diff --git a/gdb/gdbserver/config.in b/gdb/gdbserver/config.in
index dda7c1f150..b2a34b92ce 100644
--- a/gdb/gdbserver/config.in
+++ b/gdb/gdbserver/config.in
@@ -126,6 +126,9 @@
 /* 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
 
@@ -202,6 +205,9 @@
 /* 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
 
diff --git a/gdb/gdbserver/configure b/gdb/gdbserver/configure
index 340ca7a19e..6d7c9b2326 100755
--- a/gdb/gdbserver/configure
+++ b/gdb/gdbserver/configure
@@ -8455,6 +8455,64 @@ if $want_ipa ; then
    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
+
+
 
 
 
diff --git a/gdb/gdbserver/configure.ac b/gdb/gdbserver/configure.ac
index 6727959e61..7c0f508275 100644
--- a/gdb/gdbserver/configure.ac
+++ b/gdb/gdbserver/configure.ac
@@ -488,6 +488,10 @@ if $want_ipa ; then
    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)
diff --git a/gdb/gdbserver/linux-low.c b/gdb/gdbserver/linux-low.c
index cfb2b56a08..0faac80625 100644
--- a/gdb/gdbserver/linux-low.c
+++ b/gdb/gdbserver/linux-low.c
@@ -963,7 +963,21 @@ linux_ptrace_fun ()
 {
   if (ptrace (PTRACE_TRACEME, 0, (PTRACE_TYPE_ARG3) 0,
 	      (PTRACE_TYPE_ARG4) 0) < 0)
-    trace_start_error_with_name ("ptrace");
+    {
+      int save_errno = errno;
+      struct buffer buffer;
+
+      buffer_init (&buffer);
+      linux_ptrace_create_warnings (&buffer);
+      buffer_grow_str0 (&buffer, "");
+
+      std::string msg
+	= string_printf (_("%sCannot trace created process"),
+			 buffer_finish (&buffer));
+
+      errno = save_errno;
+      trace_start_error_with_name (msg.c_str ());
+    }
 
   if (setpgid (0, 0) < 0)
     trace_start_error_with_name ("setpgid");
diff --git a/gdb/linux-nat.c b/gdb/linux-nat.c
index c41ea391a0..1570a2bcb6 100644
--- a/gdb/linux-nat.c
+++ b/gdb/linux-nat.c
@@ -1127,7 +1127,29 @@ linux_nat_create_inferior (struct target_ops *ops,
   /* 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);
+  volatile struct gdb_exception ex;
+  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
 }
 
 /* Callback for linux_proc_attach_tgid_threads.  Attach to PTID if not
diff --git a/gdb/nat/linux-ptrace.c b/gdb/nat/linux-ptrace.c
index ac6ba72390..be51e2449b 100644
--- a/gdb/nat/linux-ptrace.c
+++ b/gdb/nat/linux-ptrace.c
@@ -27,6 +27,10 @@
 #include <sys/procfs.h>
 #endif
 
+#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.  */
@@ -51,6 +55,8 @@ linux_ptrace_attach_fail_reason (pid_t pid, struct buffer *buffer)
     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.  */
@@ -594,6 +600,22 @@ linux_ptrace_init_warnings (void)
   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
diff --git a/gdb/nat/linux-ptrace.h b/gdb/nat/linux-ptrace.h
index 1f960ed132..84912f909c 100644
--- a/gdb/nat/linux-ptrace.h
+++ b/gdb/nat/linux-ptrace.h
@@ -190,6 +190,7 @@ extern void linux_ptrace_attach_fail_reason (pid_t pid, struct buffer *buffer);
 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);
-- 
2.14.3