Hi,

While fuzzing nsd-checkzone with American Fuzzy Lop, I found an out-of-bounds read caused by improper validation of array index, in the rdata_maximum_wireformat_size() function, in rdata.c L873.

Attaching a reproducer (gzipped so GitHub accepts it), issue can be reproduced by running:

nsd-checkzone all.rr zone01

zone01.gz