commit cd6058ed8ebf2ffef4944cab076f605c52e9049b Author: teor teor@torproject.org Date: Wed Jul 25 15:37:57 2018 +1000

rend-spec-v3: harmonise client and service link specifiers in EXTENDs

Closes bug 26925. --- rend-spec-v3.txt | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/rend-spec-v3.txt b/rend-spec-v3.txt index 0b56fce..eb1ba42 100644 --- a/rend-spec-v3.txt +++ b/rend-spec-v3.txt @@ -1343,6 +1343,15 @@ Table of contents: The link-specifiers is a base64 encoding of a link specifier block in the format described in BUILDING-BLOCKS.

+ The client SHOULD NOT reject any LSTYPE fields which it doesn't + recognize; instead, it should use them verbatim in its EXTEND + request to the introduction point. + + The client MAY perform basic validity checks on the link + specifiers in the descriptor. These checks SHOULD NOT leak + detailed information about the client's version, configuration, + or consensus. (See 3.3 for service link specifier handling.) + "onion-key" SP "ntor" SP key NL

[Exactly once per introduction point] @@ -1702,9 +1711,10 @@ Table of contents: in [BUILDING-BLOCKS], the "TLS-over-TCP, IPv4" and "Legacy node identity" specifiers must be present.

- The hidden service SHOULD NOT reject any LSTYPE fields which it - doesn't recognize; instead, it should use them verbatim in its EXTEND - request to the rendezvous point. + The hidden service should handle invalid or unrecognised link specifiers + the same way as clients do in section 2.5.2.2. In particular, services + MAY perform basic validity checks on link specifiers, and SHOULD NOT + reject unrecognised link specifiers, to avoid information leaks.

The ONION_KEY_TYPE field is: