PIC build error ubuntu, libressl

[mcarpenter]

Building commit 748ed6 of s2n on Ubuntu 14.04 x86_64 with gcc 4.8.4 and the (default) bfd linker.

I've tried libressl versions 2.2.0, 2.1.7, 2.0.5 and all produce similar errors when I try to make s2n:

gcc -shared -lc -lpthread -lrt -o libs2n.so ../utils/s2n_blob.o ../utils/s2n_mem.o ../utils/s2n_random.o ../utils/s2n_safety.o ../utils/s2n_timer.o ../stuffer/s2n_stuffer_base64.o ../stuffer/s2n_stuffer_file.o ../stuffer/s2n_stuffer.o ../stuffer/s2n_stuffer_pem.o ../stuffer/s2n_stuffer_text.o ../tls/s2n_aead.o ../tls/s2n_alerts.o ../tls/s2n_cbc.o ../tls/s2n_cipher_suites.o ../tls/s2n_client_ccs.o ../tls/s2n_client_extensions.o ../tls/s2n_client_finished.o ../tls/s2n_client_hello.o ../tls/s2n_client_key_exchange.o ../tls/s2n_config.o ../tls/s2n_connection.o ../tls/s2n_handshake_io.o ../tls/s2n_handshake.o ../tls/s2n_ocsp_stapling.o ../tls/s2n_prf.o ../tls/s2n_record_read.o ../tls/s2n_record_write.o ../tls/s2n_recv.o ../tls/s2n_send.o ../tls/s2n_server_ccs.o ../tls/s2n_server_cert.o ../tls/s2n_server_done.o ../tls/s2n_server_extensions.o ../tls/s2n_server_finished.o ../tls/s2n_server_hello.o ../tls/s2n_server_key_exchange.o ../tls/s2n_tls.o ../crypto/s2n_aead_cipher_aes_gcm.o ../crypto/s2n_cbc_cipher_3des.o ../crypto/s2n_cbc_cipher_aes.o ../crypto/s2n_dhe.o ../crypto/s2n_drbg.o ../crypto/s2n_ecc.o ../crypto/s2n_hash.o ../crypto/s2n_hmac.o ../crypto/s2n_rsa.o ../crypto/s2n_sequence.o ../crypto/s2n_stream_cipher_null.o ../crypto/s2n_stream_cipher_rc4.o ../error/s2n_errno.o ../libcrypto-root/lib/libcrypto.a
/usr/bin/ld: ../libcrypto-root/lib/libcrypto.a(libcrypto_la-cryptlib.o): relocation R_X86_64_32 against `.rodata.str1.8' can not be used when making a shared object; recompile with -fPIC
../libcrypto-root/lib/libcrypto.a: error adding symbols: Bad value
collect2: error: ld returned 1 exit status
make[1]: *** [libs2n.so] Error 1
make[1]: Leaving directory `/home/mcarpenter/s2n/lib'
make: *** [libs] Error 2

Following the hint it's enough to do export CFLAGS=-fPIC before building libressl (2.2.0) and then s2n. (Even then the s2n build doesn't quite complete since tests fail... but one step at a time).

Is this just a doc error ("please set CFLAGS")? Or is there something more fundamentally wrong?

[mcarpenter]

Okay, so now ("hmm, what next") the build notes for BoringSSL and I see that explicitly states to set the PIC flag:

cmake -DCMAKE_C_FLAGS="-fPIC" ../

so I guess the same really is appropriate for libressl, and this is just a doc omission.