Hello and best wishes for new year, I was debugging an invalid memory access in gnutls and realized that the issue is in memxor3 of nettle (2.7.x branch). I have not yet a fix for that, but the attached patch modifies the memxor-test.c to reproduce the issue.
regards, Nikos
$ valgrind ./memxor-test [...] ==26108== Invalid read of size 8 ==26108== at 0x4E817BD: memxor3 (memxor.s:137) ==26108== by 0x4029D8: test_main (memxor-test.c:157) ==26108== by 0x4024C6: main (testutils.c:204) ==26108== Address 0x5094498 is 104 bytes inside a block of size 111 alloc'd ==26108== at 0x4A0645D: malloc (in /usr/lib64/valgrind/vgpreload_memcheck-amd64-linux.so) ==26108== by 0x402909: test_main (memxor-test.c:152) ==26108== by 0x4024C6: main (testutils.c:204) ==26108== ==26108==