Hello, Gentle reminder to check if the proposed patch works :-)
Thanks, Bhargava On 07/30/2018 11:58 AM, Bhargava Shastry wrote: > Any updates on the proposed patch? :-) > > On 07/16/2018 02:07 PM, Bhargava Shastry wrote: >> Update: I fixed these errors in the attached patch that supersedes the >> patch here (https://patchwork.ozlabs.org/patch/942118/) >> >> The major change is that I add the following line for each fuzz target >> binary in the tests/oss-fuzz/automake.mk file: >> >> e.g., >> tests_oss_fuzz_flow_extract_target_LDFLAGS = $(LIB_FUZZING_ENGINE) \ >> -lc++ >> >> Regards, >> Bhargava >> >> On 07/16/2018 11:45 AM, Bhargava Shastry wrote: >>> Oops, here's the link failure log: >>> >>> ``` >>> /usr/lib/gcc/x86_64-linux-gnu/5.4.0/../../../x86_64-linux-gnu/crt1.o: In >>> function `_start': >>> (.text+0x20): undefined reference to `main' >>> clang-7: error: linker command failed with exit code 1 (use -v to see >>> invocation) >>> Makefile:4159: recipe for target 'tests/oss-fuzz/flow_extract_target' failed >>> make: *** [tests/oss-fuzz/flow_extract_target] Error 1 >>> fuzzers build failed. >>> ``` >>> >>> The main symbol is provided by libfuzzer (clang++ -lFuzzingEngine) >>> >>> Regards, >>> Bhargava >>> >>> On 07/16/2018 11:36 AM, Bhargava Shastry wrote: >>>> Hi Ben, >>>> >>>>> Never mind that one, I failed to check in some of that. >>>>> >>>>> I sent it formally: >>>>> https://patchwork.ozlabs.org/patch/942118/ >>>> >>>> Thanks for the patch. This fixes the previous error. Now, there are some >>>> new errors during the compilation/linking process. I think most of this >>>> can be fixed if I figure out how automake works. In a nutshell, here's >>>> the problem: >>>> >>>> - oss-fuzz provides compilation flags that can be plugged in like so >>>> ``` >>>> CC=clang >>>> CXX=clang++ >>>> CFLAGS=-O1 -fno-omit-frame-pointer -gline-tables-only >>>> -DFUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION -fsanitize=address >>>> -fsanitize-address-use-after-scope -fsanitize=fuzzer-no-link >>>> CXXFLAGS=-O1 -fno-omit-frame-pointer -gline-tables-only >>>> -DFUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION -fsanitize=address >>>> -fsanitize-address-use-after-scope -fsanitize=fuzzer-no-link -stdlib=libc++ >>>> ``` >>>> >>>> And here's what I used to do before >>>> >>>> - Use clang and CFLAGS above plus some additional includes to compile >>>> each of the fuzzer tests >>>> - Use clang++ and additional linker flags to link these into a fuzzer >>>> binary >>>> >>>> Now, I see that the compilation works >>>> ``` >>>> depbase=`echo tests/oss-fuzz/flow_extract_target.o | sed >>>> 's|[^/]*$|.deps/&|;s|\.o$||'`;\ >>>> clang -DHAVE_CONFIG_H -I. -I ./include -I ./include -I ./lib -I ./lib >>>> -I/usr/include -Wstrict-prototypes -Wall -Wextra -Wno-sign-compare >>>> -Wpointer-arith -Wformat -Wformat-security -Wswitch-enum >>>> -Wunused-parameter -Wbad-function-cast -Wcast-align -Wstrict-prototypes >>>> -Wold-style-definition -Wmissing-prototypes -Wmissing-field-initializers >>>> -Wthread-safety -fno-strict-aliasing -Wswitch-bool >>>> -Wlogical-not-parentheses -Wsizeof-array-argument -Wshift-negative-value >>>> -Qunused-arguments -Wshadow -Wno-null-pointer-arithmetic -O1 >>>> -fno-omit-frame-pointer -gline-tables-only >>>> -DFUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION -fsanitize=address >>>> -fsanitize-address-use-after-scope -fsanitize=fuzzer-no-link -MT >>>> tests/oss-fuzz/flow_extract_target.o -MD -MP -MF $depbase.Tpo -c -o >>>> tests/oss-fuzz/flow_extract_target.o >>>> tests/oss-fuzz/flow_extract_target.c &&\ >>>> mv -f $depbase.Tpo $depbase.Po >>>> ``` >>>> >>>> However, the linking fails >>>> ``` >>>> libtool: link: clang -Wstrict-prototypes -Wall -Wextra -Wno-sign-compare >>>> -Wpointer-arith -Wformat -Wformat-security -Wswitch-enum >>>> -Wunused-parameter -Wbad-function-cast -Wcast-align -Wstrict-prototypes >>>> -Wold-style-definition -Wmissing-prototypes -Wmissing-field-initializers >>>> -Wthread-safety -fno-strict-aliasing -Wswitch-bool >>>> -Wlogical-not-parentheses -Wsizeof-array-argument -Wshift-negative-value >>>> -Qunused-arguments -Wshadow -Wno-null-pointer-arithmetic -O1 >>>> -fno-omit-frame-pointer -gline-tables-only >>>> -DFUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION -fsanitize=address >>>> -fsanitize-address-use-after-scope -fsanitize=fuzzer-no-link -o >>>> tests/oss-fuzz/flow_extract_target tests/oss-fuzz/flow_extract_target.o >>>> -L/usr/lib lib/.libs/libopenvswitch.a -lssl -lcrypto -latomic >>>> ``` >>>> >>>> I think adding -lFuzzingEngine should fix this but another variable >>>> between my build script and automake is the use of clang++ for linking. >>>> >>>> Do you know how I can experiment with different linker flags and >>>> compiler/linker in automake? >>>> >>>> Regards, >>>> Bhargava >>>> >>>> >>> >> > -- Bhargava Shastry <[email protected]> Security in Telecommunications TU Berlin / Telekom Innovation Laboratories Ernst-Reuter-Platz 7, Sekr TEL 17 / D - 10587 Berlin, Germany phone: +49 30 8353 58235 Keybase: https://keybase.io/bshastry _______________________________________________ dev mailing list [email protected] https://mail.openvswitch.org/mailman/listinfo/ovs-dev
