From FEDORA_PATCHES Mon Sep 17 00:00:00 2001 From: Fedora GDB patches Date: Fri, 27 Oct 2017 21:07:50 +0200 Subject: 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 * 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. diff --git a/gdb/config.in b/gdb/config.in --- a/gdb/config.in +++ b/gdb/config.in @@ -251,6 +251,9 @@ /* 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 @@ -386,6 +389,9 @@ /* 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 diff --git a/gdb/configure b/gdb/configure --- a/gdb/configure +++ b/gdb/configure @@ -16434,6 +16434,64 @@ 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 --- a/gdb/configure.ac +++ b/gdb/configure.ac @@ -1964,6 +1964,10 @@ 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 --- a/gdb/gdbserver/config.in +++ b/gdb/gdbserver/config.in @@ -125,6 +125,9 @@ /* Define to 1 if you have the `dl' library (-ldl). */ #undef HAVE_LIBDL +/* Define to 1 if you have the `selinux' library (-lselinux). */ +#undef HAVE_LIBSELINUX + /* Define if the target supports branch tracing. */ #undef HAVE_LINUX_BTRACE @@ -210,6 +213,9 @@ /* 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 diff --git a/gdb/gdbserver/configure b/gdb/gdbserver/configure --- a/gdb/gdbserver/configure +++ b/gdb/gdbserver/configure @@ -9398,6 +9398,64 @@ 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 --- a/gdb/gdbserver/configure.ac +++ b/gdb/gdbserver/configure.ac @@ -465,6 +465,10 @@ 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 --- a/gdb/gdbserver/linux-low.c +++ b/gdb/gdbserver/linux-low.c @@ -968,7 +968,16 @@ 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; + + std::string msg (linux_ptrace_create_warnings ()); + + msg += _("Cannot trace created process"); + + 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 --- a/gdb/linux-nat.c +++ b/gdb/linux-nat.c @@ -1092,7 +1092,16 @@ linux_nat_target::create_inferior (const char *exec_file, /* Make sure we report all signals during startup. */ pass_signals ({}); - inf_ptrace_target::create_inferior (exec_file, allargs, env, from_tty); + try + { + inf_ptrace_target::create_inferior (exec_file, allargs, env, from_tty); + } + catch (const gdb_exception_error &ex) + { + std::string result = linux_ptrace_create_warnings (); + + throw_error (ex.error, "%s%s", result.c_str (), ex.message->c_str ()); + } } /* 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 --- a/gdb/nat/linux-ptrace.c +++ b/gdb/nat/linux-ptrace.c @@ -25,6 +25,10 @@ #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. */ @@ -50,6 +54,8 @@ linux_ptrace_attach_fail_reason (pid_t pid) "terminated"), (int) pid); + result += linux_ptrace_create_warnings (); + return result; } @@ -586,6 +592,25 @@ linux_ptrace_init_warnings (void) linux_ptrace_test_ret_to_nx (); } +/* Print all possible reasons we could fail to create a traced process. */ + +std::string +linux_ptrace_create_warnings () +{ + std::string result; + +#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) + string_appendf (result, + _("the SELinux boolean 'deny_ptrace' is enabled, " + "you can disable this process attach protection by: " + "(gdb) shell sudo setsebool deny_ptrace=0\n")); +#endif /* HAVE_LIBSELINUX */ + return result; +} + /* Extract extended ptrace event from wait status. */ int diff --git a/gdb/nat/linux-ptrace.h b/gdb/nat/linux-ptrace.h --- a/gdb/nat/linux-ptrace.h +++ b/gdb/nat/linux-ptrace.h @@ -184,6 +184,7 @@ extern std::string linux_ptrace_attach_fail_reason (pid_t pid); extern std::string linux_ptrace_attach_fail_reason_string (ptid_t ptid, int err); extern void linux_ptrace_init_warnings (void); +extern std::string linux_ptrace_create_warnings (); 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);