Commit ec1b8020 authored by Nick Mathewson's avatar Nick Mathewson 🤹
Browse files

Merge remote-tracking branch 'dgoulet/bug21290_030_01'

parents 24551d64 5335a8e6

changes/bug21290

0 → 100644
+7 −0
Original line number Diff line number Diff line 
  o Minor bugfixes (configure, autoconf):

    - Rename the configure option --enable-expensive-hardening to

      --enable-fragile-hardening. TROVE-2017-001 was triggerable only through

      the expensive hardening which is making the tor daemon abort when the

      issue is detected. Thus, it makes tor more at risk of remote crashes but

      safer against RCE or heartbleed bug category. Fixes bug 21290; bugfix on

      tor-0.2.5.4-alpha.

configure.ac

+25 −4
Original line number Diff line number Diff line
@@ -145,8 +145,14 @@ dnl Others suggest '/gs /safeseh /nxcompat /dynamicbase' for non-gcc on Windows 
AC_ARG_ENABLE(gcc-hardening,

    AS_HELP_STRING(--disable-gcc-hardening, [disable compiler security checks]))



dnl Deprecated --enable-expensive-hardening but keep it for now for backward compat.

AC_ARG_ENABLE(expensive-hardening,

    AS_HELP_STRING(--enable-expensive-hardening, [enable more expensive compiler hardening; makes Tor slower]))

    AS_HELP_STRING(--enable-expensive-hardening, [enable more fragile and expensive compiler hardening; makes Tor slower]))

AC_ARG_ENABLE(fragile-hardening,

    AS_HELP_STRING(--enable-fragile-hardening, [enable more fragile and expensive compiler hardening; makes Tor slower]))

if test "x$enable_expensive_hardening" = "xyes" || test "x$enable_fragile_hardening" = "xyes"; then

  fragile_hardening="yes"

fi



dnl Linker hardening options

dnl Currently these options are ELF specific - you can't use this with MacOSX
@@ -777,14 +783,14 @@ m4_ifdef([AS_VAR_IF],[ 
    TOR_TRY_COMPILE_WITH_CFLAGS(-fwrapv, also_link, CFLAGS_FWRAPV="-fwrapv", true)

fi



if test "x$enable_expensive_hardening" = "xyes"; then

if test "$fragile_hardening" = "yes"; then

    TOR_TRY_COMPILE_WITH_CFLAGS(-ftrapv, also_link, CFLAGS_FTRAPV="-ftrapv", true)

   if test "$tor_cv_cflags__ftrapv" = "yes" && test "$tor_can_link__ftrapv" != "yes"; then

      AC_MSG_WARN([The compiler supports -ftrapv, but for some reason I was not able to link with -ftrapv. Are you missing run-time support? Run-time hardening will not work as well as it should.])

   fi



   if test "$tor_cv_cflags__ftrapv" != "yes"; then

     AC_MSG_ERROR([You requested expensive hardening, but the compiler does not seem to support -ftrapv.])

     AC_MSG_ERROR([You requested fragile hardening, but the compiler does not seem to support -ftrapv.])

   fi



   TOR_TRY_COMPILE_WITH_CFLAGS([-fsanitize=address], also_link, CFLAGS_ASAN="-fsanitize=address", true)
@@ -866,7 +872,7 @@ saved_CFLAGS="$CFLAGS" 
TOR_CHECK_CFLAGS(-fomit-frame-pointer)

F_OMIT_FRAME_POINTER=''

if test "$saved_CFLAGS" != "$CFLAGS"; then

  if test "x$enable_expensive_hardening" != "xyes"; then

  if test "$fragile_hardening" = "yes"; then

    F_OMIT_FRAME_POINTER='-fomit-frame-pointer'

  fi

fi
@@ -1965,4 +1971,19 @@ if test "x$asciidoc" = "xtrue" && test "$ASCIIDOC" = "none"; then 
  done

fi



if test "$fragile_hardening" = "yes"; then

  AC_MSG_WARN([



============

Warning!  Building Tor with --enable-fragile-hardening (also known as

--enable-expensive-hardening) makes some kinds of attacks harder, but makes

other kinds of attacks easier. A Tor instance build with this option will be

somewhat less vulnerable to remote code execution, arithmetic overflow, or

out-of-bounds read/writes... but at the cost of becoming more vulnerable to

denial of service attacks. For more information, see

https://trac.torproject.org/projects/tor/wiki/doc/TorFragileHardening

============

  ])

fi



AC_OUTPUT