Using american fuzzy lop has found a lot of issues. It would be nice to make using it a bit easier. Our build files make sure that no shared library uses text relocations, but afl-gcc will insert some on i686. http://www.akkadia.org/drepper/textrelocs.html
Now CC=afl-gcc ./configure --disable-textrelcheck will allow them so that afl can instrument the libraries.
Don't try to use or install them except with afl-fuzz. When selinux is enabled it might prevent loading the libraries with DT_TEXTREL set.
Signed-off-by: Mark Wielaard mjw@redhat.com --- ChangeLog | 4 ++++ config/ChangeLog | 5 +++++ config/eu.am | 8 +++++++- configure.ac | 5 +++++ libasm/ChangeLog | 4 ++++ libasm/Makefile.am | 2 +- libdw/ChangeLog | 4 ++++ libdw/Makefile.am | 2 +- libelf/ChangeLog | 4 ++++ libelf/Makefile.am | 2 +- 10 files changed, 36 insertions(+), 4 deletions(-)
diff --git a/ChangeLog b/ChangeLog index 0947608..8eeaa08 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,7 @@ +2014-11-27 Mark Wielaard mjw@redhat.com + + * configure.ac: Add --disable-textrelcheck. + 2014-10-06 Mark Wielaard mjw@redhat.com
* NEWS: New section 0.161. Add dwarf_peel_type. diff --git a/config/ChangeLog b/config/ChangeLog index 9ebf14f..a05f552 100644 --- a/config/ChangeLog +++ b/config/ChangeLog @@ -1,3 +1,8 @@ +2014-11-27 Mark Wielaard mjw@redhat.com + + * eu.am: Define textrel_msg, textrel_found and textrel_check based + on FATAL_TEXTREL. + 2014-08-25 Mark Wielaard mjw@redhat.com
* elfutils.spec.in: Update for 0.160. diff --git a/config/eu.am b/config/eu.am index c3b00e0..faf8add 100644 --- a/config/eu.am +++ b/config/eu.am @@ -52,4 +52,10 @@ endif
CLEANFILES = *.gcno *.gcda
-textrel_check = if $(READELF) -d $@ | fgrep -q TEXTREL; then exit 1; fi +textrel_msg = echo "WARNING: TEXTREL found in '$@'" +if FATAL_TEXTREL +textrel_found = $(textrel_msg); exit 1 +else +textrel_found = $(textrel_msg) +endif +textrel_check = if $(READELF) -d $@ | fgrep -q TEXTREL; then $(textrel_found); fi diff --git a/configure.ac b/configure.ac index 76a172d..9bc83c5 100644 --- a/configure.ac +++ b/configure.ac @@ -212,6 +212,11 @@ AC_CHECK_LIB([stdc++], [__cxa_demangle], [dnl AC_DEFINE([USE_DEMANGLE], [1], [Defined if demangling is enabled])]) AM_CONDITIONAL(DEMANGLE, test "$ac_cv_lib_stdcpp___cxa_demangle" = yes)
+AC_ARG_ENABLE([textrelcheck], +AS_HELP_STRING([--disable-textrelcheck], + [Disable textrelcheck being a fatal error])) +AM_CONDITIONAL(FATAL_TEXTREL, [test "x$enable_textrelcheck" != "xno"]) + dnl The directories with content.
dnl Documentation. diff --git a/libasm/ChangeLog b/libasm/ChangeLog index 2613610..034a64d 100644 --- a/libasm/ChangeLog +++ b/libasm/ChangeLog @@ -1,3 +1,7 @@ +2014-01127 Mark Wielaard mjw@redhat.com + + * Makefile.am (libasm.so): Use textrel_check. + 2014-04-13 Mark Wielaard mjw@redhat.com
* Makefile.am: Remove !MUDFLAP conditions. diff --git a/libasm/Makefile.am b/libasm/Makefile.am index 3d6a2e5..88c2530 100644 --- a/libasm/Makefile.am +++ b/libasm/Makefile.am @@ -66,7 +66,7 @@ libasm.so$(EXEEXT): libasm_pic.a libasm.map -Wl,--version-script,$(srcdir)/libasm.map,--no-undefined \ -Wl,--soname,$@.$(VERSION) \ ../libebl/libebl.a ../libelf/libelf.so $(libasm_so_LDLIBS) - if $(READELF) -d $@ | fgrep -q TEXTREL; then exit 1; fi + $(textrel_check) ln -fs $@ $@.$(VERSION)
install: install-am libasm.so diff --git a/libdw/ChangeLog b/libdw/ChangeLog index c199707..bab02e5 100644 --- a/libdw/ChangeLog +++ b/libdw/ChangeLog @@ -1,5 +1,9 @@ 2014-11-27 Mark Wielaard mjw@redhat.com
+ * Makefile.am (libdw.so): Use textrel_check. + +2014-11-27 Mark Wielaard mjw@redhat.com + * dwarf_getcfi_elf.c (getcfi_gnu_eh_frame): Initialize search_table_entries and search_table_encoding.
diff --git a/libdw/Makefile.am b/libdw/Makefile.am index 852d2c8..7a2a25d 100644 --- a/libdw/Makefile.am +++ b/libdw/Makefile.am @@ -113,7 +113,7 @@ libdw.so$(EXEEXT): $(srcdir)/libdw.map libdw_pic.a ../libdwelf/libdwelf_pic.a \ -Wl,--version-script,$<,--no-undefined \ -Wl,--whole-archive $(filter-out $<,$^) -Wl,--no-whole-archive\ -ldl $(zip_LIBS) - if $(READELF) -d $@ | fgrep -q TEXTREL; then exit 1; fi + $(textrel_check) ln -fs $@ $@.$(VERSION)
install: install-am libdw.so diff --git a/libelf/ChangeLog b/libelf/ChangeLog index 68fb0fc..e03ee09 100644 --- a/libelf/ChangeLog +++ b/libelf/ChangeLog @@ -1,3 +1,7 @@ +2014-11-27 Mark Wielaard mjw@redhat.com + + * Makefile.am (libelf.so): Use textrel_check. + 2014-11-23 Mark Wielaard mjw@redhat.com
* elf_getdata_rawchunk.c (elf_getdata_rawchunk): Change signed diff --git a/libelf/Makefile.am b/libelf/Makefile.am index 493e4ec..6888529 100644 --- a/libelf/Makefile.am +++ b/libelf/Makefile.am @@ -103,7 +103,7 @@ libelf.so$(EXEEXT): libelf_pic.a libelf.map $(LINK) -shared -o $@ -Wl,--whole-archive,$<,--no-whole-archive \ -Wl,--version-script,$(srcdir)/libelf.map,--no-undefined \ -Wl,--soname,$@.$(VERSION),-z,defs,-z,relro $(libelf_so_LDLIBS) - if $(READELF) -d $@ | fgrep -q TEXTREL; then exit 1; fi + $(textrel_check) ln -fs $@ $@.$(VERSION)
install: install-am libelf.so
On Fri, 2014-11-28 at 00:08 +0100, Mark Wielaard wrote:
Using american fuzzy lop has found a lot of issues. It would be nice to make using it a bit easier. Our build files make sure that no shared library uses text relocations, but afl-gcc will insert some on i686. http://www.akkadia.org/drepper/textrelocs.html
Now CC=afl-gcc ./configure --disable-textrelcheck will allow them so that afl can instrument the libraries.
Don't try to use or install them except with afl-fuzz. When selinux is enabled it might prevent loading the libraries with DT_TEXTREL set.
I pushed this to elfutils git master now. Running on 32bit x86 Fedora has discovered some more crashers. I am currently analyzing and will post patches soon.
Thanks,
Mark
elfutils-devel@lists.fedorahosted.org