[tor-commits] [tor/master] Explain PIE/PIC rationale for 23846.

[nickm at torproject.org]

commit fae7f96e7bac60b6e6f23bfcef239a3686093cb8
Author: Nick Mathewson <nickm at torproject.org>
Date:   Thu Sep 13 14:53:20 2018 -0400

    Explain PIE/PIC rationale for 23846.
---
 configure.ac | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/configure.ac b/configure.ac
index bd300ba1b..f0673cf4c 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1164,8 +1164,12 @@ m4_ifdef([AS_VAR_IF],[
     TOR_CHECK_CFLAGS(--param ssp-buffer-size=1)
     if test "$bwin32" = "false" && test "$enable_libfuzzer" != "yes" && test "$enable_oss_fuzz" != "yes"; then
        if test "$enable_pic" != "yes"; then
+           # If we have already enabled -fPIC, then we don't also need to
+           # compile with -fPIE...
            TOR_CHECK_CFLAGS(-fPIE)
        fi
+       # ... but we want to link our executables with -pie in any case, since
+       # they're executables, not a library.
        TOR_CHECK_LDFLAGS(-pie, "$all_ldflags_for_check", "$all_libs_for_check")
     fi
     TOR_TRY_COMPILE_WITH_CFLAGS(-fwrapv, also_link, CFLAGS_FWRAPV="-fwrapv", true)