commit 54dc6a76ab467fc3bcafe929ac7e128e5b7f0438
author Maxim Dounin <mdounin@mdounin.ru> Tue May 25 15:17:41 2021 +0300
committer Maxim Dounin <mdounin@mdounin.ru> Tue May 25 15:17:41 2021 +0300
tree 12599e7139d52e391e80871a18b27070952d2aaf
parent 3f6f3d9ac0b9af037de08512b5a9d4cd01e0a276

Resolver: fixed label types handling in ngx_resolver_copy().

Previously, anything with any of the two high bits set were interpreted
as compression pointers.  This is incorrect, as RFC 1035 clearly states
that "The 10 and 01 combinations are reserved for future use".  Further,
the 01 combination is actually allocated for EDNS extended label type
(see RFC 2671 and RFC 6891), not really used though.

Fix is to reject unrecognized label types rather than misinterpreting
them as compression pointers.