RPATH no longer respected for indirect dependencies

Question

I have upgraded from Ubuntu 16.04 to Ubuntu 17.10, which moves me from:

gcc: from gcc-5.4.0 to gcc-7.2.0
ld: from ld-2.26.1 to ld-2.29.1.
glibc: from 2.3 to 2.6

I am building a binary with a hard-coded RUNPATH, pointing to the location of some vendor-supplied shared libraries.

$ readelf -d /home/steve/src/krx/tests/krx.test | grep RUNPATH
 0x000000000000001d (RUNPATH)        Library runpath: [../library]

On Ubuntu 16.04 the RUNPATH allowed us to locate the libraries.

$ ldd ./krx.test
    ...
    libinisafeNet.so => ../library/libinisafeNet.so (0x00007f35c7754000)
    libiniCore.so => ../library/libiniCore.so (0x00007f35c5bea000)
    libiniPKI.so => ../library/libiniPKI.so (0x00007f35c5952000)
    libiniCrypto.so => ../library/libiniCrypto.so (0x00007f35c56e6000)

On Ubuntu 17.10 it no longer works

$ ldd ./krx.test
    ...
    libinisafeNet.so => ../library/libinisafeNet.so (0x00007fb4acc38000)
    libiniCore.so => not found
    libiniPKI.so => not found
    libiniCrypto.so => not found

Setting LD_LIBRARY_PATH does allow the libraries to be found

$ export LD_LIBRARY_PATH=../library
$ ldd ./krx.test 
    ...
    libinisafeNet.so => ../library/libinisafeNet.so (0x00007fa787659000)
    libiniCore.so => ../library/libiniCore.so (0x00007fa785a86000)
    libiniPKI.so => ../library/libiniPKI.so (0x00007fa7857ee000)
    libiniCrypto.so => ../library/libiniCrypto.so (0x00007fa785582000)

LD_DEBUG for Ubuntu 16.04

I set LD_DEBUG=all and ran ldd against my binary.

Here is an excerpt for libiniCore.so:

 30438:     file=libiniCore.so [0];  needed by ../library/libinisafeNet.so [0]
 30438:     find library=libiniCore.so [0]; searching
 30438:      search path=../library/tls/x86_64:../library/tls:../library/x86_64:../library          (RPATH from file ./krx.test)
 30438:       trying file=../library/tls/x86_64/libiniCore.so
 30438:       trying file=../library/tls/libiniCore.so
 30438:       trying file=../library/x86_64/libiniCore.so
 30438:       trying file=../library/libiniCore.so

The library is successfully located, and as can be seen from the search path section, it is using RPATH from file ./krx.test.

LD_DEBUG for Ubuntu 17.10

I set LD_DEBUG=all and ran ldd against my binary.

Here is an excerpt for libiniCore.so: (it now uses the system search path, not the krx.test RPATH)

 20027:     file=libiniCore.so [0];  needed by ../library/libinisafeNet.so [0]
 20027:     find library=libiniCore.so [0]; searching
 20027:      search cache=/etc/ld.so.cache
 20027:      search path=/lib/x86_64-linux-gnu/tls/haswell/x86_64:/lib/x86_64-linux-gnu/tls/haswell:/lib/x86_64-linux-gnu/tls/x86_64:/lib/x86_64-linux-gnu/tls:/lib/x86_64-linux-gnu/haswell/x86_64:/lib/x86_64-linux-gnu/haswell:/lib/x86_64-linux-gnu/x86_64:/lib/x86_64-linux-gnu:/usr/lib/x86_64-linux-gnu/tls/haswell/x86_64:/usr/lib/x86_64-linux-gnu/tls/haswell:/usr/lib/x86_64-linux-gnu/tls/x86_64:/usr/lib/x86_64-linux-gnu/tls:/usr/lib/x86_64-linux-gnu/haswell/x86_64:/usr/lib/x86_64-linux-gnu/haswell:/usr/lib/x86_64-linux-gnu/x86_64:/usr/lib/x86_64-linux-gnu:/lib/tls/haswell/x86_64:/lib/tls/haswell:/lib/tls/x86_64:/lib/tls:/lib/haswell/x86_64:/lib/haswell:/lib/x86_64:/lib:/usr/lib/tls/haswell/x86_64:/usr/lib/tls/haswell:/usr/lib/tls/x86_64:/usr/lib/tls:/usr/lib/haswell/x86_64:/usr/lib/haswell:/usr/lib/x86_64:/usr/lib            (system search path)
 20027:       trying file=/lib/x86_64-linux-gnu/tls/haswell/x86_64/libiniCore.so
 20027:       trying file=/lib/x86_64-linux-gnu/tls/haswell/libiniCore.so
 20027:       trying file=/lib/x86_64-linux-gnu/tls/x86_64/libiniCore.so
 20027:       trying file=/lib/x86_64-linux-gnu/tls/libiniCore.so
 20027:       trying file=/lib/x86_64-linux-gnu/haswell/x86_64/libiniCore.so
 20027:       trying file=/lib/x86_64-linux-gnu/haswell/libiniCore.so
 20027:       trying file=/lib/x86_64-linux-gnu/x86_64/libiniCore.so
 ...          ...
 20027:       trying file=/lib/x86_64/libiniCore.so
 20027:       trying file=/lib/libiniCore.so
 20027:       trying file=/usr/lib/tls/haswell/x86_64/libiniCore.so
 20027:       trying file=/usr/lib/tls/haswell/libiniCore.so
 20027:       trying file=/usr/lib/tls/x86_64/libiniCore.so
 20027:       trying file=/usr/lib/tls/libiniCore.so
 20027:       trying file=/usr/lib/haswell/x86_64/libiniCore.so
 20027:       trying file=/usr/lib/haswell/libiniCore.so
 20027:       trying file=/usr/lib/x86_64/libiniCore.so
 20027:       trying file=/usr/lib/libiniCore.so

So it seems the behaviour of ld has changed, and since it is an indirect dependency (krx.test --> libinisafeNet.so --> libiniCore.so) the RPATH for krx.test is no longer used.

Question:

Is this a regression?
Is the only way around this (without updating ld.so.conf) to set the RPATH on my shared libraries too?
Is there a way to set the RPATH on my binary so that it can locate the indirect dependencies?

RPATH no longer respected for indirect dependencies

0 Answers0