commit 21ac292820da5784cf3c87e77df57b7594071d09 Author: Nick Mathewson nickm@torproject.org Date: Mon Oct 21 13:07:47 2013 -0400
Give a better warning when stack protection breaks linking.
Fix for 9948; patch from Benedikt Gollatz. --- acinclude.m4 | 9 +++++++++ changes/bug9948 | 6 ++++++ configure.ac | 11 ++++++++++- 3 files changed, 25 insertions(+), 1 deletion(-)
diff --git a/acinclude.m4 b/acinclude.m4 index af15051..2943734 100644 --- a/acinclude.m4 +++ b/acinclude.m4 @@ -43,6 +43,8 @@ AC_DEFUN([TOR_DEFINE_CODEPATH], ])
dnl 1:flags +dnl 2:also try to link (yes: non-empty string) +dnl will set yes or no in $tor_can_link_$1 (as modified by AS_VAR_PUSHDEF) AC_DEFUN([TOR_CHECK_CFLAGS], [ AS_VAR_PUSHDEF([VAR],[tor_cv_cflags_$1]) AC_CACHE_CHECK([whether the compiler accepts $1], VAR, [ @@ -51,6 +53,13 @@ AC_DEFUN([TOR_CHECK_CFLAGS], [ AC_TRY_COMPILE([], [return 0;], [AS_VAR_SET(VAR,yes)], [AS_VAR_SET(VAR,no)]) + if test x$2 != x; then + AS_VAR_PUSHDEF([can_link],[tor_can_link_$1]) + AC_TRY_LINK([], [return 0;], + [AS_VAR_SET(can_link,yes)], + [AS_VAR_SET(can_link,no)]) + AS_VAR_POPDEF([can_link]) + fi CFLAGS="$tor_saved_CFLAGS" ]) if test x$VAR = xyes; then diff --git a/changes/bug9948 b/changes/bug9948 new file mode 100644 index 0000000..6a673c0 --- /dev/null +++ b/changes/bug9948 @@ -0,0 +1,6 @@ + o Minor features (build): + + - Check in configure whether we can link an executable when + stack protection is enabled so we can warn the user about a + potentially missing libssp. Addresses ticket 9948. Patch + from Benedikt Gollatz. diff --git a/configure.ac b/configure.ac index 77767c5..f1fa881 100644 --- a/configure.ac +++ b/configure.ac @@ -589,7 +589,16 @@ if test x$enable_gcc_hardening != xno; then if test x$have_clang = xyes; then TOR_CHECK_CFLAGS(-Qunused-arguments) fi - TOR_CHECK_CFLAGS(-fstack-protector-all) + TOR_CHECK_CFLAGS(-fstack-protector-all, also_link) + AS_VAR_PUSHDEF([can_compile], [tor_cv_cflags_-fstack-protector-all]) + AS_VAR_PUSHDEF([can_link], [tor_can_link_-fstack-protector-all]) + AS_VAR_IF(can_compile, [yes], + AS_VAR_IF(can_link, [yes], + [], + AC_MSG_ERROR([We tried to build with stack protection; it looks like your compiler supports it but your libc does not provide it. Are you missing libssp? (You can --disable-gcc-hardening to ignore this error.)])) + ) + AS_VAR_POPDEF([can_link]) + AS_VAR_POPDEF([can_compile]) TOR_CHECK_CFLAGS(-Wstack-protector) TOR_CHECK_CFLAGS(-fwrapv) TOR_CHECK_CFLAGS(--param ssp-buffer-size=1)