afl++ build is broken on openssl_x509

[jonathanmetzman]

CC @andreafioraldi

Similar to #107 CI successfully built openssl_x509 with AFL++ but failed to do so on 2020-03-11.

The build fails with this error:

/afl/afl-clang-fast  -Iinclude  -pthread -m64 -fno-omit-frame-pointer -g -Wa,--noexecstack -Qunused-arguments -pthread -Wl,--no-as-needed -Wl,-ldl -Wl,-lm -Wno-unused-command-line-argument -O2 -pthread -Wno-unus
ed-command-line-argument -O2 -fno-sanitize=alignment  -DPEDANTIC -DFUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION -MMD -MF test/buildtest_c_e_os2-bin-buildtest_e_os2.d.tmp -MT test/buildtest_c_e_os2-bin-buildtest_e_os
2.o -c -o test/buildtest_c_e_os2-bin-buildtest_e_os2.o test/buildtest_e_os2.c
test/p_test-dso-p_test.o: In function `OSSL_provider_init':
/src/openssl/test/p_test.c:(.text+0x2b): undefined reference to `__afl_area_ptr'
/src/openssl/test/p_test.c:(.text+0x44): undefined reference to `__afl_prev_loc'
/src/openssl/test/p_test.c:(.text+0x7c): undefined reference to `__afl_prev_loc'
test/p_test-dso-p_test.o: In function `p_get_params':
/src/openssl/test/p_test.c:(.text+0x189): undefined reference to `__afl_prev_loc'
/src/openssl/test/p_test.c:(.text+0x198): undefined reference to `__afl_area_ptr'
/src/openssl/test/p_test.c:57: undefined reference to `__afl_prev_loc'
/src/openssl/test/p_test.c:57: undefined reference to `__afl_area_ptr'
/src/openssl/test/p_test.c:93: undefined reference to `__afl_prev_loc'
/src/openssl/test/p_test.c:93: undefined reference to `__afl_area_ptr'
/src/openssl/test/p_test.c:(.text+0x3e8): undefined reference to `__afl_prev_loc'
/src/openssl/test/p_test.c:(.text+0x3f7): undefined reference to `__afl_area_ptr'
clang-10: error: linker command failed with exit code 1 (use -v to see invocation

I will try to investigate the fix for this as well as if there is a way to make CI more likely to catch failures that happen in production.

[jonathanmetzman]

I think #115 is why this wasn't caught by CI

[andreafioraldi]

Super strange, seems that afl-llvm-rt is not linked in the test.

[alifahmed]

This can be fixed by skipping the check of maybe_linking flag in afl-clang-fast.c.
Irrespective of the value of maybe_linking, the afl-llvm-rt.o (and its 32/64 variants) should be added to the cc_params.

[andreafioraldi]

I fixed it in the dev branch https://github.com/AFLplusplus/AFLplusplus/tree/dev with the solution proposed by @alifahmed . Waiting travis, then I'll merge it and update fuzzbench.