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Commit ce854a8d authored by Nick Mathewson's avatar Nick Mathewson :game_die:
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Add -ftrapv to gcc-hardening ... mostly! 

We know there are overflows in curve25519-donna-c32, so we'll have
to have that one be fwrapv.

Only apply the asan, ubsan, and trapv options to the code that does
not need to run in constant time.  Those options introduce branches
to the code they instrument.

(These introduced branches should never actually be taken, so it
might _still_ be constant time after all, but branch predictors are
complicated enough that I'm not really confident here. Let's aim for
safety.)

Closes 17983.
parent bd34edc1
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......@@ -132,6 +132,9 @@ uptime-*.json
/src/common/libor.a
/src/common/libor-testing.a
/src/common/libor.lib
/src/common/libor-ctime.a
/src/common/libor-ctime-testing.a
/src/common/libor-ctime.lib
/src/common/libor-crypto.a
/src/common/libor-crypto-testing.a
/src/common/libor-crypto.lib
......
Makefile.am
+ 2
− 2
View file @ ce854a8d
......@@ -15,8 +15,8 @@ noinst_PROGRAMS=
DISTCLEANFILES=
bin_SCRIPTS=
AM_CPPFLAGS=
AM_CFLAGS = @TOR_SYSTEMD_CFLAGS@
SHELL = @SHELL@
AM_CFLAGS=@TOR_SYSTEMD_CFLAGS@ @CFLAGS_BUGTRAP@
SHELL=@SHELL@
if COVERAGE_ENABLED
TESTING_TOR_BINARY="$(top_builddir)/src/or/tor-cov"
......
acinclude.m4
+ 15
− 5
View file @ ce854a8d
......@@ -42,10 +42,11 @@ AC_DEFUN([TOR_DEFINE_CODEPATH],
AC_SUBST(TOR_LDFLAGS_$2)
])
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], [
dnl 1: flags
dnl 2: try to link too if this is nonempty.
dnl 3: what to do on success compiling
dnl 4: what to do on failure compiling
AC_DEFUN([TOR_TRY_COMPILE_WITH_CFLAGS], [
AS_VAR_PUSHDEF([VAR],[tor_cv_cflags_$1])
AC_CACHE_CHECK([whether the compiler accepts $1], VAR, [
tor_saved_CFLAGS="$CFLAGS"
......@@ -63,11 +64,20 @@ AC_DEFUN([TOR_CHECK_CFLAGS], [
CFLAGS="$tor_saved_CFLAGS"
])
if test x$VAR = xyes; then
CFLAGS="$CFLAGS $1"
$3
else
$4
fi
AS_VAR_POPDEF([VAR])
])
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], [
TOR_TRY_COMPILE_WITH_CFLAGS($1, $2, CFLAGS="$CFLAGS $1", /bin/true)
])
dnl 1:flags
dnl 2:extra ldflags
dnl 3:extra libraries
......
changes/bug17983 0 → 100644
+ 11
− 0
View file @ ce854a8d
o Minor features (bug-finding):
- Tor now builds with -ftrapv by default on compilers that support it.
This option detects signed integer overflow, and turns it into a
hard-failure. We do not apply this option to code that needs to run
in constant time to avoid side-channels; instead, we use -fwrapv.
Closes ticket 17983.
- When --enable-expensive-hardening is selected, stop applying the clang/gcc
sanitizers to code that needs to run in constant-time to avoid side
channels: although we are aware of no introduced side-channels, we
are not able to prove that this is safe. Related to ticket 17983.
configure.ac
+ 20
− 3
View file @ ce854a8d
......@@ -755,6 +755,11 @@ dnl use it with a build of a library.
all_ldflags_for_check="$TOR_LDFLAGS_zlib $TOR_LDFLAGS_openssl $TOR_LDFLAGS_libevent"
all_libs_for_check="$TOR_ZLIB_LIBS $TOR_LIB_MATH $TOR_LIBEVENT_LIBS $TOR_OPENSSL_LIBS $TOR_SYSTEMD_LIBS $TOR_LIB_WS32 $TOR_LIB_GDI $TOR_CAP_LIBS"
CFLAGS_FTRAPV=
CFLAGS_FWRAPV=
CFLAGS_ASAN=
CFLAGS_UBSAN=
AC_COMPILE_IFELSE([AC_LANG_PROGRAM([], [
#if !defined(__clang__)
#error
......@@ -777,20 +782,32 @@ m4_ifdef([AS_VAR_IF],[
AS_VAR_POPDEF([can_link])
AS_VAR_POPDEF([can_compile])
TOR_CHECK_CFLAGS(-Wstack-protector)
TOR_CHECK_CFLAGS(-fwrapv)
TOR_CHECK_CFLAGS(--param ssp-buffer-size=1)
if test "$bwin32" = "false"; then
TOR_CHECK_CFLAGS(-fPIE)
TOR_CHECK_LDFLAGS(-pie, "$all_ldflags_for_check", "$all_libs_for_check")
fi
TOR_TRY_COMPILE_WITH_CFLAGS(-ftrapv, , CFLAGS_FTRAPV="-ftrapv", /bin/true)
TOR_TRY_COMPILE_WITH_CFLAGS(-fwrapv, , CFLAGS_FWRAPV="-fwrapv", /bin/true)
fi
if test "x$enable_expensive_hardening" = "xyes"; then
TOR_CHECK_CFLAGS([-fsanitize=address])
TOR_CHECK_CFLAGS([-fsanitize=undefined])
TOR_TRY_COMPILE_WITH_CFLAGS([-fsanitize=address], , CFLAGS_ASAN="-fsanitize=address", /bin/true)
TOR_TRY_COMPILE_WITH_CFLAGS([-fsanitize=undefined], , CFLAGS_UBSAN="-fsanitize=undefined", /bin/true)
TOR_CHECK_CFLAGS([-fno-omit-frame-pointer])
fi
CFLAGS_BUGTRAP="$CFLAGS_FTRAPV $CFLAGS_ASAN $CFLAGS_UBSAN"
CFLAGS_CONSTTIME="$CFLAGS_FWRAPV"
dnl These cflags add bunches of branches, and we haven't been able to
dnl persuade ourselves that they're suitable for code that needs to be
dnl constant time.
AC_SUBST(CFLAGS_BUGTRAP)
dnl These cflags are variant ones sutable for code that needs to be
dnl constant-time.
AC_SUBST(CFLAGS_CONSTTIME)
if test "x$enable_linker_hardening" != "xno"; then
TOR_CHECK_LDFLAGS(-z relro -z now, "$all_ldflags_for_check", "$all_libs_for_check")
fi
......
src/common/include.am
+ 14
− 3
View file @ ce854a8d
noinst_LIBRARIES += \
src/common/libor.a \
src/common/libor-ctime.a \
src/common/libor-crypto.a \
src/common/libor-event.a
if UNITTESTS_ENABLED
noinst_LIBRARIES += \
src/common/libor-testing.a \
src/common/libor-ctime-testing.a \
src/common/libor-crypto-testing.a \
src/common/libor-event-testing.a
endif
......@@ -27,12 +29,14 @@ src_common_libcurve25519_donna_a_CFLAGS=
if BUILD_CURVE25519_DONNA
src_common_libcurve25519_donna_a_SOURCES=\
src/ext/curve25519_donna/curve25519-donna.c
# See bug 13538 -- this code is known to have signed overflow issues.
src_common_libcurve25519_donna_a_CFLAGS+=\
@F_OMIT_FRAME_POINTER@
@F_OMIT_FRAME_POINTER@ @CFLAGS_CONSTTIME@
noinst_LIBRARIES+=src/common/libcurve25519_donna.a
LIBDONNA=src/common/libcurve25519_donna.a
else
if BUILD_CURVE25519_DONNA_C64
src_common_libcurve25519_donna_a_CFLAGS+=@CFLAGS_CONSTTIME@
src_common_libcurve25519_donna_a_SOURCES=\
src/ext/curve25519_donna/curve25519-donna-c64.c
noinst_LIBRARIES+=src/common/libcurve25519_donna.a
......@@ -58,13 +62,21 @@ else
readpassphrase_source=
endif
LIBOR_CTIME_A_SOURCES = \
src/ext/csiphash.c \
src/common/di_ops.c
src_common_libor_ctime_a_SOURCES = $(LIBOR_CTIME_A_SOURCES)
src_common_libor_ctime_testing_a_SOURCES = $(LIBOR_CTIME_A_SOURCES)
src_common_libor_ctime_a_CFLAGS = @CFLAGS_CONSTTIME@
src_common_libor_ctime_testing_a_CFLAGS = @CFLAGS_CONSTTIME@ $(TEST_CFLAGS)
LIBOR_A_SOURCES = \
src/common/address.c \
src/common/backtrace.c \
src/common/compat.c \
src/common/compat_threads.c \
src/common/container.c \
src/common/di_ops.c \
src/common/log.c \
src/common/memarea.c \
src/common/util.c \
......@@ -72,7 +84,6 @@ LIBOR_A_SOURCES = \
src/common/util_process.c \
src/common/sandbox.c \
src/common/workqueue.c \
src/ext/csiphash.c \
src/ext/trunnel/trunnel.c \
$(libor_extra_source) \
$(threads_impl_source) \
......
src/ext/include.am
+ 6
− 3
View file @ ce854a8d
......@@ -16,7 +16,8 @@ EXTHEADERS = \
noinst_HEADERS+= $(EXTHEADERS)
src_ext_ed25519_ref10_libed25519_ref10_a_CFLAGS=
src_ext_ed25519_ref10_libed25519_ref10_a_CFLAGS=\
@CFLAGS_CONSTTIME@
src_ext_ed25519_ref10_libed25519_ref10_a_SOURCES= \
src/ext/ed25519/ref10/fe_0.c \
......@@ -93,7 +94,8 @@ noinst_HEADERS += $(ED25519_REF10_HDRS)
LIBED25519_REF10=src/ext/ed25519/ref10/libed25519_ref10.a
noinst_LIBRARIES += $(LIBED25519_REF10)
src_ext_ed25519_donna_libed25519_donna_a_CFLAGS= \
src_ext_ed25519_donna_libed25519_donna_a_CFLAGS=\
@CFLAGS_CONSTTIME@ \
-DED25519_CUSTOMRANDOM \
-DED25519_SUFFIX=_donna
......@@ -135,7 +137,8 @@ noinst_HEADERS += $(ED25519_DONNA_HDRS)
LIBED25519_DONNA=src/ext/ed25519/donna/libed25519_donna.a
noinst_LIBRARIES += $(LIBED25519_DONNA)
src_ext_keccak_tiny_libkeccak_tiny_a_CFLAGS=
src_ext_keccak_tiny_libkeccak_tiny_a_CFLAGS=\
@CFLAGS_CONSTTIME@
src_ext_keccak_tiny_libkeccak_tiny_a_SOURCES= \
src/ext/keccak-tiny/keccak-tiny-unrolled.c
......
src/or/include.am
+ 2
− 1
View file @ ce854a8d
......@@ -109,7 +109,7 @@ src_or_libtor_testing_a_CFLAGS = $(AM_CFLAGS) $(TEST_CFLAGS)
src_or_tor_LDFLAGS = @TOR_LDFLAGS_zlib@ @TOR_LDFLAGS_openssl@ @TOR_LDFLAGS_libevent@
src_or_tor_LDADD = src/or/libtor.a src/common/libor.a \
src_or_tor_LDADD = src/or/libtor.a src/common/libor.a src/common/libor-ctime.a \
src/common/libor-crypto.a $(LIBKECCAK_TINY) $(LIBDONNA) \
src/common/libor-event.a src/trunnel/libor-trunnel.a \
@TOR_ZLIB_LIBS@ @TOR_LIB_MATH@ @TOR_LIBEVENT_LIBS@ @TOR_OPENSSL_LIBS@ \
......@@ -121,6 +121,7 @@ src_or_tor_cov_CPPFLAGS = $(AM_CPPFLAGS) $(TEST_CPPFLAGS)
src_or_tor_cov_CFLAGS = $(AM_CFLAGS) $(TEST_CFLAGS)
src_or_tor_cov_LDFLAGS = @TOR_LDFLAGS_zlib@ @TOR_LDFLAGS_openssl@ @TOR_LDFLAGS_libevent@
src_or_tor_cov_LDADD = src/or/libtor-testing.a src/common/libor-testing.a \
src/common/libor-ctime-testing.a \
src/common/libor-crypto-testing.a $(LIBKECCAK_TINY) $(LIBDONNA) \
src/common/libor-event-testing.a src/trunnel/libor-trunnel-testing.a \
@TOR_ZLIB_LIBS@ @TOR_LIB_MATH@ @TOR_LIBEVENT_LIBS@ @TOR_OPENSSL_LIBS@ \
......
src/test/include.am
+ 6
− 0
View file @ ce854a8d
......@@ -147,6 +147,7 @@ src_test_test_switch_id_CFLAGS = $(AM_CFLAGS) $(TEST_CFLAGS)
src_test_test_switch_id_LDFLAGS = @TOR_LDFLAGS_zlib@
src_test_test_switch_id_LDADD = \
src/common/libor-testing.a \
src/common/libor-ctime-testing.a \
@TOR_ZLIB_LIBS@ @TOR_LIB_MATH@
src_test_test_LDFLAGS = @TOR_LDFLAGS_zlib@ @TOR_LDFLAGS_openssl@ \
......@@ -156,6 +157,7 @@ src_test_test_LDADD = src/or/libtor-testing.a \
$(LIBKECCAK_TINY) \
$(LIBDONNA) \
src/common/libor-testing.a \
src/common/libor-ctime-testing.a \
src/common/libor-event-testing.a \
src/trunnel/libor-trunnel-testing.a \
@TOR_ZLIB_LIBS@ @TOR_LIB_MATH@ @TOR_LIBEVENT_LIBS@ \
......@@ -175,6 +177,7 @@ src_test_test_memwipe_LDFLAGS = $(src_test_test_LDFLAGS)
src_test_bench_LDFLAGS = @TOR_LDFLAGS_zlib@ @TOR_LDFLAGS_openssl@ \
@TOR_LDFLAGS_libevent@
src_test_bench_LDADD = src/or/libtor.a src/common/libor.a \
src/common/libor-ctime.a \
src/common/libor-crypto.a $(LIBKECCAK_TINY) $(LIBDONNA) \
src/common/libor-event.a src/trunnel/libor-trunnel.a \
@TOR_ZLIB_LIBS@ @TOR_LIB_MATH@ @TOR_LIBEVENT_LIBS@ \
......@@ -185,6 +188,7 @@ src_test_test_workqueue_LDFLAGS = @TOR_LDFLAGS_zlib@ @TOR_LDFLAGS_openssl@ \
@TOR_LDFLAGS_libevent@
src_test_test_workqueue_LDADD = src/or/libtor-testing.a \
src/common/libor-testing.a \
src/common/libor-ctime-testing.a \
src/common/libor-crypto-testing.a $(LIBKECCAK_TINY) $(LIBDONNA) \
src/common/libor-event-testing.a \
@TOR_ZLIB_LIBS@ @TOR_LIB_MATH@ @TOR_LIBEVENT_LIBS@ \
......@@ -208,6 +212,7 @@ noinst_PROGRAMS+= src/test/test-ntor-cl
src_test_test_ntor_cl_SOURCES = src/test/test_ntor_cl.c
src_test_test_ntor_cl_LDFLAGS = @TOR_LDFLAGS_zlib@ @TOR_LDFLAGS_openssl@
src_test_test_ntor_cl_LDADD = src/or/libtor.a src/common/libor.a \
src/common/libor-ctime.a \
src/common/libor-crypto.a $(LIBKECCAK_TINY) $(LIBDONNA) \
@TOR_ZLIB_LIBS@ @TOR_LIB_MATH@ \
@TOR_OPENSSL_LIBS@ @TOR_LIB_WS32@ @TOR_LIB_GDI@ @CURVE25519_LIBS@
......@@ -217,6 +222,7 @@ src_test_test_ntor_cl_AM_CPPFLAGS = \
noinst_PROGRAMS += src/test/test-bt-cl
src_test_test_bt_cl_SOURCES = src/test/test_bt_cl.c
src_test_test_bt_cl_LDADD = src/common/libor-testing.a \
src/common/libor-ctime-testing.a \
@TOR_LIB_MATH@ \
@TOR_LIB_WS32@ @TOR_LIB_GDI@
src_test_test_bt_cl_CFLAGS = $(AM_CFLAGS) $(TEST_CFLAGS)
......
src/tools/include.am
+ 9
− 2
View file @ ce854a8d
......@@ -7,19 +7,23 @@ endif
src_tools_tor_resolve_SOURCES = src/tools/tor-resolve.c
src_tools_tor_resolve_LDFLAGS =
src_tools_tor_resolve_LDADD = src/common/libor.a @TOR_LIB_MATH@ @TOR_LIB_WS32@
src_tools_tor_resolve_LDADD = src/common/libor.a \
src/common/libor-ctime.a \
@TOR_LIB_MATH@ @TOR_LIB_WS32@
if COVERAGE_ENABLED
src_tools_tor_cov_resolve_SOURCES = src/tools/tor-resolve.c
src_tools_tor_cov_resolve_CPPFLAGS = $(AM_CPPFLAGS) $(TEST_CPPFLAGS)
src_tools_tor_cov_resolve_CFLAGS = $(AM_CFLAGS) $(TEST_CFLAGS)
src_tools_tor_cov_resolve_LDADD = src/common/libor-testing.a \
src/common/libor-ctime-testing.a \
@TOR_LIB_MATH@ @TOR_LIB_WS32@
endif
src_tools_tor_gencert_SOURCES = src/tools/tor-gencert.c
src_tools_tor_gencert_LDFLAGS = @TOR_LDFLAGS_zlib@ @TOR_LDFLAGS_openssl@
src_tools_tor_gencert_LDADD = src/common/libor.a src/common/libor-crypto.a \
src/common/libor-ctime.a \
$(LIBKECCAK_TINY) \
$(LIBDONNA) \
@TOR_LIB_MATH@ @TOR_ZLIB_LIBS@ @TOR_OPENSSL_LIBS@ \
......@@ -31,6 +35,7 @@ src_tools_tor_cov_gencert_CPPFLAGS = $(AM_CPPFLAGS) $(TEST_CPPFLAGS)
src_tools_tor_cov_gencert_CFLAGS = $(AM_CFLAGS) $(TEST_CFLAGS)
src_tools_tor_cov_gencert_LDFLAGS = @TOR_LDFLAGS_zlib@ @TOR_LDFLAGS_openssl@
src_tools_tor_cov_gencert_LDADD = src/common/libor-testing.a \
src/common/libor-ctime-testing.a \
src/common/libor-crypto-testing.a \
$(LIBKECCAK_TINY) \
$(LIBDONNA) \
......@@ -40,7 +45,9 @@ endif
src_tools_tor_checkkey_SOURCES = src/tools/tor-checkkey.c
src_tools_tor_checkkey_LDFLAGS = @TOR_LDFLAGS_zlib@ @TOR_LDFLAGS_openssl@
src_tools_tor_checkkey_LDADD = src/common/libor.a src/common/libor-crypto.a \
src_tools_tor_checkkey_LDADD = src/common/libor.a \
src/common/libor-ctime.a \
src/common/libor-crypto.a \
$(LIBKECCAK_TINY) \
$(LIBDONNA) \
@TOR_LIB_MATH@ @TOR_ZLIB_LIBS@ @TOR_OPENSSL_LIBS@ \
......
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