Up until the recent updates (after 2018.08) an internal application using the old setkey()/encrypt() functions was able to compile. With latest master, compilation fails: /home/buildroot/project/output/host/bin/powerpc64le-buildroot-linux-gnu-gcc -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -Os -fstack-protector-all -Wl,-z,relro -D_FORTIFY_SOURCE=2 -fPIC proprietary.o -o proprietary -lcrypt -lcurl /home/buildroot/project/output/host/lib/gcc/powerpc64le-buildroot-linux-gnu/8.2.0/../../../../powerpc64le-buildroot-linux-gnu/bin/ld: proprietary.o: in function `legacy_handler': proprietary.c:(.text+0x1cc30): undefined reference to `setkey' /home/buildroot/project/output/host/lib/gcc/powerpc64le-buildroot-linux-gnu/8.2.0/../../../../powerpc64le-buildroot-linux-gnu/bin/ld: proprietary.c:(.text+0x1cce4): undefined reference to `encrypt' collect2: error: ld returned 1 exit status Makefile:62: recipe for target 'proprietary' failed make[1]: *** [proprietary] Error 1 make[1]: Leaving directory '/home/buildroot/project/output/build/proprietary-origin_master/proprietary' package/pkg-generic.mk:229: recipe for target '/home/buildroot/project/output/build/proprietary-origin_master/.stamp_built' failed make: *** [/home/buildroot/project/output/build/proprietary-origin_master/.stamp_built] Error 2
This is a decision from glibc upstream, which removed those functions from glibc 2.28. See https://lists.gnu.org/archive/html/info-gnu/2018-08/msg00000.html, which says: """ * The obsolete functions encrypt, encrypt_r, setkey, setkey_r, cbc_crypt, ecb_crypt, and des_setparity are no longer available to newly linked binaries, and the headers <rpc/des_crypt.h> and <rpc/rpc_des.h> are no longer installed. These functions encrypted and decrypted data with the DES block cipher, which is no longer considered secure. Software that still uses these functions should switch to a modern cryptography library, such as libgcrypt. """ So, you should fix your application it seems. Buildroot is not going to revert this change, unless you can convince glibc upstream developers to also revert it, which I guess will be challenging.
Good to know, thanks! Wasn't able to find documentation supporting that even after some extensive searching.