| Message ID | 1589296951-75730-1-git-send-email-u9012063@gmail.com |
|---|---|
| State | Rejected |
| Headers | show |
| Series | [ovs-dev,1/2] oss-fuzz: Fix fuzzer flags in CFLAGS. | expand |
On 5/12/20 5:22 PM, William Tu wrote: > When running fuzzer locally by doing > $ ./configure CC=clang CFLAGS="-g -O2 -fsanitize=fuzzer-no-link -Werror" Hmm... Why passing 'fuzzer-no-link' to replace it inside the make script? > $ make oss-fuzz-targets AFAIK, oss-fuzz-targets are for Google's oss-fuzz project and not for local usage. > fails due to "(.text+0x20): undefined reference to `main'" > > The patch fixes it by replacing "fuzzer-no-link" to "fuzzer" so the > binary under tests/oss-fuzz/ can be generated. > > Cc: Bhargava Shastry <bshastry@sect.tu-berlin.de> > Cc: Yifeng Sun <pkusunyifeng@gmail.com> > Signed-off-by: William Tu <u9012063@gmail.com> > --- > tests/oss-fuzz/automake.mk | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/tests/oss-fuzz/automake.mk b/tests/oss-fuzz/automake.mk > index 2b116e7a51a1..66a5c3037f5d 100644 > --- a/tests/oss-fuzz/automake.mk > +++ b/tests/oss-fuzz/automake.mk > @@ -8,6 +8,9 @@ OSS_FUZZ_TARGETS = \ > EXTRA_PROGRAMS += $(OSS_FUZZ_TARGETS) > oss-fuzz-targets: $(OSS_FUZZ_TARGETS) > > +CFLAGS_FUZZER:=$(CFLAGS:fuzzer-no-link=fuzzer) > +override CFLAGS=$(CFLAGS_FUZZER) > + > tests_oss_fuzz_flow_extract_target_SOURCES = \ > tests/oss-fuzz/flow_extract_target.c \ > tests/oss-fuzz/fuzzer.h >
Thanks for taking a look. On Tue, May 12, 2020 at 8:41 AM Ilya Maximets <i.maximets@ovn.org> wrote: > > On 5/12/20 5:22 PM, William Tu wrote: > > When running fuzzer locally by doing > > $ ./configure CC=clang CFLAGS="-g -O2 -fsanitize=fuzzer-no-link -Werror" > > Hmm... Why passing 'fuzzer-no-link' to replace it inside the make script? the configure fails i`f passing as "-fsanitize=fuzzer" configure: error: C compiler cannot create executables See `config.log' for more details configure:4079: checking whether the C compiler works configure:4101: clang -g -O2 -fsanitize=fuzzer -Werror conftest.c >&5 /tmp/conftest-67bd49.o: In function `main': /root/ovs/conftest.c:14: multiple definition of `main' /usr/lib/llvm-8/lib/clang/8.0.0/lib/linux/libclang_rt.fuzzer-x86_64.a(FuzzerMain.cpp.o):FuzzerMain.cpp:(.text.main+0x0): first defined here /usr/lib/llvm-8/lib/clang/8.0.0/lib/linux/libclang_rt.fuzzer-x86_64.a(FuzzerMain.cpp.o): In function `main': FuzzerMain.cpp:(.text.main+0x12): undefined reference to `LLVMFuzzerTestOneInput' clang: error: linker command failed with exit code 1 (use -v to see invocation) configure:4105: $? = 1 configure:4143: result: no configure: failed program was: > > > $ make oss-fuzz-targets > > AFAIK, oss-fuzz-targets are for Google's oss-fuzz project and not for > local usage. We're thinking about adding more tests under tests/oss-fuzz/ so need to make it work locally first. William > > > fails due to "(.text+0x20): undefined reference to `main'" > > > > The patch fixes it by replacing "fuzzer-no-link" to "fuzzer" so the > > binary under tests/oss-fuzz/ can be generated. > > > > Cc: Bhargava Shastry <bshastry@sect.tu-berlin.de> > > Cc: Yifeng Sun <pkusunyifeng@gmail.com> > > Signed-off-by: William Tu <u9012063@gmail.com> > > --- > > tests/oss-fuzz/automake.mk | 3 +++ > > 1 file changed, 3 insertions(+) > > > > diff --git a/tests/oss-fuzz/automake.mk b/tests/oss-fuzz/automake.mk > > index 2b116e7a51a1..66a5c3037f5d 100644 > > --- a/tests/oss-fuzz/automake.mk > > +++ b/tests/oss-fuzz/automake.mk > > @@ -8,6 +8,9 @@ OSS_FUZZ_TARGETS = \ > > EXTRA_PROGRAMS += $(OSS_FUZZ_TARGETS) > > oss-fuzz-targets: $(OSS_FUZZ_TARGETS) > > > > +CFLAGS_FUZZER:=$(CFLAGS:fuzzer-no-link=fuzzer) > > +override CFLAGS=$(CFLAGS_FUZZER) > > + > > tests_oss_fuzz_flow_extract_target_SOURCES = \ > > tests/oss-fuzz/flow_extract_target.c \ > > tests/oss-fuzz/fuzzer.h > > >
On Tue, May 12, 2020 at 8:44 AM William Tu <u9012063@gmail.com> wrote: > > Thanks for taking a look. > > On Tue, May 12, 2020 at 8:41 AM Ilya Maximets <i.maximets@ovn.org> wrote: > > > > On 5/12/20 5:22 PM, William Tu wrote: > > > When running fuzzer locally by doing > > > $ ./configure CC=clang CFLAGS="-g -O2 -fsanitize=fuzzer-no-link -Werror" > > > > Hmm... Why passing 'fuzzer-no-link' to replace it inside the make script? > > the configure fails i`f passing as "-fsanitize=fuzzer" > configure: error: C compiler cannot create executables > See `config.log' for more details > > configure:4079: checking whether the C compiler works > configure:4101: clang -g -O2 -fsanitize=fuzzer -Werror conftest.c >&5 > /tmp/conftest-67bd49.o: In function `main': > /root/ovs/conftest.c:14: multiple definition of `main' > /usr/lib/llvm-8/lib/clang/8.0.0/lib/linux/libclang_rt.fuzzer-x86_64.a(FuzzerMain.cpp.o):FuzzerMain.cpp:(.text.main+0x0): > first defined here > /usr/lib/llvm-8/lib/clang/8.0.0/lib/linux/libclang_rt.fuzzer-x86_64.a(FuzzerMain.cpp.o): > In function `main': > FuzzerMain.cpp:(.text.main+0x12): undefined reference to > `LLVMFuzzerTestOneInput' > clang: error: linker command failed with exit code 1 (use -v to see invocation) > configure:4105: $? = 1 > configure:4143: result: no > configure: failed program was: > > > > > > $ make oss-fuzz-targets > > > > AFAIK, oss-fuzz-targets are for Google's oss-fuzz project and not for > > local usage. > > We're thinking about adding more tests under tests/oss-fuzz/ > so need to make it work locally first. > Some context: People told me that using fuzzer can detect integer wraparound/overflow bug, something like this meter bucket issue. https://mail.openvswitch.org/pipermail/ovs-dev/2020-May/370291.html So I start to look at how clang fuzzer works in OVS. It requires us to pick the fuzzer target function, and in this meter bucket case, it's pretty hard to do it. Regards, William
diff --git a/tests/oss-fuzz/automake.mk b/tests/oss-fuzz/automake.mk index 2b116e7a51a1..66a5c3037f5d 100644 --- a/tests/oss-fuzz/automake.mk +++ b/tests/oss-fuzz/automake.mk @@ -8,6 +8,9 @@ OSS_FUZZ_TARGETS = \ EXTRA_PROGRAMS += $(OSS_FUZZ_TARGETS) oss-fuzz-targets: $(OSS_FUZZ_TARGETS) +CFLAGS_FUZZER:=$(CFLAGS:fuzzer-no-link=fuzzer) +override CFLAGS=$(CFLAGS_FUZZER) + tests_oss_fuzz_flow_extract_target_SOURCES = \ tests/oss-fuzz/flow_extract_target.c \ tests/oss-fuzz/fuzzer.h
When running fuzzer locally by doing $ ./configure CC=clang CFLAGS="-g -O2 -fsanitize=fuzzer-no-link -Werror" $ make oss-fuzz-targets fails due to "(.text+0x20): undefined reference to `main'" The patch fixes it by replacing "fuzzer-no-link" to "fuzzer" so the binary under tests/oss-fuzz/ can be generated. Cc: Bhargava Shastry <bshastry@sect.tu-berlin.de> Cc: Yifeng Sun <pkusunyifeng@gmail.com> Signed-off-by: William Tu <u9012063@gmail.com> --- tests/oss-fuzz/automake.mk | 3 +++ 1 file changed, 3 insertions(+)