kdf: fix unaligned memory access in balloon_xor_block
* cipher/kdf.c (balloon_xor_block): Use 'buf_xor' helper function; Change pointer parameters to 'void *' type. (balloon_final): Don't cast last_block to 'u64 *' for balloon_xor_block call.
Seen on s390x UBSAN:
/home/testbuild/libgcrypt/cipher/kdf.c:1130:12: runtime error: load of misaligned address 0x00400181370c for type 'u64', which requires 8 byte alignment
0x00400181370c: note: pointer points here
01 01 01 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
^
#0 0x4001a3f3d3 (/run/user/1006/libgcrypt/build_s390x-linux-gnu_ubsan/src/.libs/libgcrypt.so.20+0x1f83d3)
#1 0x40019cf049 (/run/user/1006/libgcrypt/build_s390x-linux-gnu_ubsan/src/.libs/libgcrypt.so.20+0x188049)
#2 0x400000acbf (/run/user/1006/libgcrypt/build_s390x-linux-gnu_ubsan/tests/t-kdf+0xacbf)
#3 0x4000008931 (/run/user/1006/libgcrypt/build_s390x-linux-gnu_ubsan/tests/t-kdf+0x8931)
#4 0x400271a031 (/lib/libc.so.6+0x2b031)
#5 0x400271a10d (/lib/libc.so.6+0x2b10d)
#6 0x4000009bcf (/run/user/1006/libgcrypt/build_s390x-linux-gnu_ubsan/tests/t-kdf+0x9bcf)- GnuPG-bug-id: T5817
- Signed-off-by: Jussi Kivilinna <jussi.kivilinna@iki.fi>