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 * 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-7.12.50.20170226/gdb/nat/linux-ptrace.c =================================================================== --- gdb-7.12.50.20170226.orig/gdb/nat/linux-ptrace.c 2017-02-26 21:27:14.780009449 +0100 +++ gdb-7.12.50.20170226/gdb/nat/linux-ptrace.c 2017-02-26 21:27:18.838038193 +0100 @@ -27,6 +27,10 @@ #include #endif +#ifdef HAVE_SELINUX_SELINUX_H +# include +#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 @@ 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_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-7.12.50.20170226/gdb/nat/linux-ptrace.h =================================================================== --- gdb-7.12.50.20170226.orig/gdb/nat/linux-ptrace.h 2017-02-26 21:27:14.780009449 +0100 +++ gdb-7.12.50.20170226/gdb/nat/linux-ptrace.h 2017-02-26 21:27:18.838038193 +0100 @@ -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-7.12.50.20170226/gdb/configure.ac =================================================================== --- gdb-7.12.50.20170226.orig/gdb/configure.ac 2017-02-26 21:27:14.781009456 +0100 +++ gdb-7.12.50.20170226/gdb/configure.ac 2017-02-26 21:27:18.839038200 +0100 @@ -2092,6 +2092,10 @@ 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-7.12.50.20170226/gdb/gdbserver/configure.ac =================================================================== --- gdb-7.12.50.20170226.orig/gdb/gdbserver/configure.ac 2017-02-26 21:27:14.781009456 +0100 +++ gdb-7.12.50.20170226/gdb/gdbserver/configure.ac 2017-02-26 21:27:18.839038200 +0100 @@ -469,6 +469,10 @@ 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-7.12.50.20170226/gdb/gdbserver/linux-low.c =================================================================== --- gdb-7.12.50.20170226.orig/gdb/gdbserver/linux-low.c 2017-02-26 21:27:14.783009470 +0100 +++ gdb-7.12.50.20170226/gdb/gdbserver/linux-low.c 2017-02-26 21:27:18.841038214 +0100 @@ -946,6 +946,29 @@ 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. */ @@ -969,7 +992,7 @@ 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-7.12.50.20170226/gdb/linux-nat.c =================================================================== --- gdb-7.12.50.20170226.orig/gdb/linux-nat.c 2017-02-26 21:27:14.785009484 +0100 +++ gdb-7.12.50.20170226/gdb/linux-nat.c 2017-02-26 21:27:18.842038221 +0100 @@ -1110,6 +1110,7 @@ { 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. */ @@ -1117,7 +1118,28 @@ /* 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-7.12.50.20170226/gdb/config.in =================================================================== --- gdb-7.12.50.20170226.orig/gdb/config.in 2017-02-26 21:27:14.786009491 +0100 +++ gdb-7.12.50.20170226/gdb/config.in 2017-02-26 21:27:18.842038221 +0100 @@ -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 header file. */ #undef HAVE_LIBUNWIND_IA64_H @@ -402,6 +405,9 @@ /* Define to 1 if you have the `scm_new_smob' function. */ #undef HAVE_SCM_NEW_SMOB +/* Define to 1 if you have the header file. */ +#undef HAVE_SELINUX_SELINUX_H + /* Define to 1 if you have the `setlocale' function. */ #undef HAVE_SETLOCALE Index: gdb-7.12.50.20170226/gdb/configure =================================================================== --- gdb-7.12.50.20170226.orig/gdb/configure 2017-02-26 21:27:14.790009519 +0100 +++ gdb-7.12.50.20170226/gdb/configure 2017-02-26 21:27:18.846038249 +0100 @@ -15492,6 +15492,64 @@ _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 $LIBS" + +fi + + # Support for --with-sysroot is a copy of GDB_AC_WITH_DIR, # except that the argument to --with-sysroot is optional. Index: gdb-7.12.50.20170226/gdb/gdbserver/config.in =================================================================== --- gdb-7.12.50.20170226.orig/gdb/gdbserver/config.in 2017-02-26 21:27:14.791009527 +0100 +++ gdb-7.12.50.20170226/gdb/gdbserver/config.in 2017-02-26 21:27:18.846038249 +0100 @@ -123,6 +123,9 @@ /* Define to 1 if you have the `mcheck' library (-lmcheck). */ #undef HAVE_LIBMCHECK +/* Define to 1 if you have the `selinux' library (-lselinux). */ +#undef HAVE_LIBSELINUX + /* Define if the target supports branch tracing. */ #undef HAVE_LINUX_BTRACE @@ -199,6 +202,9 @@ /* Define to 1 if you have the `pwrite' function. */ #undef HAVE_PWRITE +/* Define to 1 if you have the header file. */ +#undef HAVE_SELINUX_SELINUX_H + /* Define to 1 if you have the `setns' function. */ #undef HAVE_SETNS Index: gdb-7.12.50.20170226/gdb/gdbserver/configure =================================================================== --- gdb-7.12.50.20170226.orig/gdb/gdbserver/configure 2017-02-26 21:27:14.793009541 +0100 +++ gdb-7.12.50.20170226/gdb/gdbserver/configure 2017-02-26 21:27:18.848038263 +0100 @@ -8429,6 +8429,64 @@ fi fi +for ac_header in selinux/selinux.h +do : + ac_fn_c_check_header_mongrel "$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 + +