tree f9c4b1a89c2e6f016baed5d914681e6886be4e53
parent b1beaa302c4c35080f217ce5fb63fed4530e1879
author Tim Duesterhus <tim@bastelstu.be> 1583445320 +0100
committer Willy Tarreau <w@1wt.eu> 1583489482 +0100
encoding latin1

BUG/MAJOR: proxy_protocol: Properly validate TLV lengths

This patch fixes PROXYv2 parsing when the payload of the TCP connection is
fused with the PROXYv2 header within a single recv() call.

Previously HAProxy ignored the PROXYv2 header length when attempting to
parse the TLV, possibly interpreting the first byte of the payload as a
TLV type.

This patch adds proper validation. It ensures that:

1. TLV parsing stops when the end of the PROXYv2 header is reached.
2. TLV lengths cannot exceed the PROXYv2 header length.
3. The PROXYv2 header ends together with the last TLV, not allowing for
   "stray bytes" to be ignored.

A reg-test was added to ensure proper behavior.

This patch tries to find the sweat spot between a small and easily
backportable one, and a cleaner one that's more easily adaptable to
older versions, hence why it merges the "if" and "while" blocks which
causes a reindent of the whole block. It should be used as-is for
versions 1.9 to 2.1, the block about PP2_TYPE_AUTHORITY should be
dropped for 2.0 and the block about CRC32C should be dropped for 1.8.

This bug was introduced when TLV parsing was added. This happened in commit
b3e54fe387c7c1ea750f39d3029672d640c499f9. This commit was first released
with HAProxy 1.6-dev1.

A similar issue was fixed in commit 7209c204bd6f3c49132264c7a58f689cdc741c12.

This patch must be backported to HAProxy 1.6+.