From c03a265030fefb1652469ff98a8b895b8f61b771 Mon Sep 17 00:00:00 2001 From: Andrew Bartlett Date: Thu, 22 Oct 2020 15:39:50 +1300 Subject: [PATCH] oss-fuzz: standardise on RPATH for the static-ish binaries This includes a revert of commit e60df214998afc145ca482cab184691b3ddc3bb2. We strictly require RPATH, not the modern RUNPATH for the behaviour we need in oss-fuzz, which is that not just the first line of dependencies but the full set of libraries used by the program are looked for in the '$ORIGIN/lib' directory. Signed-off-by: Andrew Bartlett Reviewed-by: Douglas Bagnall Autobuild-User(master): Douglas Bagnall Autobuild-Date(master): Thu Oct 22 14:10:04 UTC 2020 on sn-devel-184 --- lib/fuzzing/oss-fuzz/build_samba.sh | 21 +++++++++------------ lib/fuzzing/oss-fuzz/check_build.sh | 13 +++++++++++-- script/autobuild.py | 2 +- 3 files changed, 21 insertions(+), 15 deletions(-) diff --git a/lib/fuzzing/oss-fuzz/build_samba.sh b/lib/fuzzing/oss-fuzz/build_samba.sh index c9a5162f801..28c37a793cc 100755 --- a/lib/fuzzing/oss-fuzz/build_samba.sh +++ b/lib/fuzzing/oss-fuzz/build_samba.sh @@ -63,7 +63,7 @@ case "$SANITIZER" in # cc style options, so we can just set ADDITIONAL_LDFLAGS # to ensure the coverage build is done, despite waf splitting # the compile and link phases. - ADDITIONAL_LDFLAGS="$COVERAGE_FLAGS" + ADDITIONAL_LDFLAGS="${ADDITIONAL_LDFLAGS:-} $COVERAGE_FLAGS" export ADDITIONAL_LDFLAGS SANITIZER_ARG='' @@ -113,19 +113,16 @@ do cp $x $OUT/ bin=`basename $x` - # Change any RPATH to RUNPATH. + # Changing RPATH (not RUNPATH, but we can't tell here which was + # set) is critical, otherwise libraries used by libraries won't be + # found on the oss-fuzz target host. Sadly this is only possible + # with clang or ld.bfd on Ubuntu 16.04 (this script is only run on + # that). # - # We use ld.bfd for the coverage builds, rather than the faster ld.gold. + # chrpath --convert only allows RPATH to be changed to RUNPATH, + # not the other way around, and we really don't want RUNPATH. # - # On Ubuntu 16.04, used for the oss-fuzz build, when linking with - # ld.bfd the binaries get a RPATH, but builds in Ubuntu 18.04 - # ld.bfd and those using ld.gold get a RUNPATH. - # - # Just convert them all to RUNPATH to make the check_build.sh test - # easier. - chrpath -c $OUT/$bin - # Change RUNPATH so that the copied libraries are found on the - # runner + # This means the copied libraries are found on the runner chrpath -r '$ORIGIN/lib' $OUT/$bin # Truncate the original binary to save space diff --git a/lib/fuzzing/oss-fuzz/check_build.sh b/lib/fuzzing/oss-fuzz/check_build.sh index b971d2c1bb0..501c2c813fc 100755 --- a/lib/fuzzing/oss-fuzz/check_build.sh +++ b/lib/fuzzing/oss-fuzz/check_build.sh @@ -23,12 +23,21 @@ do continue fi # Confirm that the chrpath was reset to lib/ in the same directory - # as the binary - chrpath -l $bin | grep 'RUNPATH=$ORIGIN/lib' + # as the binary. RPATH (not RUNPATH) is critical, otherwise + # libraries used by libraries won't be found on the oss-fuzz + # target host, but is only possible with clang or ld.bfd on Ubuntu + # 16.04 (this script is only run on that). + chrpath -l $bin | grep 'RPATH=$ORIGIN/lib' # Confirm that we link to at least some libraries in this # directory (shows that the libraries were found and copied). ldd $bin | grep "$OUT/lib" + num_libs=$(ldd $bin | grep -v ld-linux | grep -v linux-vdso | grep -v "$OUT/lib"| wc -l) + + if [ 0$num_libs -ne 0 ]; then + echo "some libraries not linked to $ORIGIN/lib, oss-fuzz will fail!" + exit 1 + fi if [ -f ${bin}_seed_corpus.zip ]; then seeds_found=yes diff --git a/script/autobuild.py b/script/autobuild.py index 0bf80d5e821..00ed3a47022 100755 --- a/script/autobuild.py +++ b/script/autobuild.py @@ -651,7 +651,7 @@ tasks = { "samba-fuzz": [ # build the fuzzers (static) via the oss-fuzz script ("fuzzers-mkdir-prefix", "mkdir -p ${PREFIX_DIR}"), - ("fuzzers-build", "OUT=${PREFIX_DIR} LIB_FUZZING_ENGINE= SANITIZER=address CXX= CFLAGS= ./lib/fuzzing/oss-fuzz/build_samba.sh --enable-afl"), + ("fuzzers-build", "OUT=${PREFIX_DIR} LIB_FUZZING_ENGINE= SANITIZER=address CXX= CFLAGS= ADDITIONAL_LDFLAGS='-fuse-ld=bfd' ./lib/fuzzing/oss-fuzz/build_samba.sh --enable-afl"), ("fuzzers-check", "./lib/fuzzing/oss-fuzz/check_build.sh ${PREFIX_DIR}") ],