Previously, we hashed the question and combined it with the original
txid which was useful when concurrent queries were multiplexed on a
single local source port. We encountered some situations where the DNS
server canonicalizes the question in the response (uppercase converted
to lowercase in this case), which resulted in responses that we couldn't
match to the original request due to hash mismatches. This includes a
new test to cover that situation.
Fixes#2597
Signed-off-by: Adrian Dewhurst <adrian@tailscale.com>
This change (subject to some limitations) looks for the EDNS OPT record
in queries and responses, clamping the size field to fit within our DNS
receive buffer. If the size field is smaller than the DNS receive buffer
then it is left unchanged.
I think we will eventually need to transition to fully processing the
DNS queries to handle all situations, but this should cover the most
common case.
Mostly fixes#2066
Signed-off-by: Adrian Dewhurst <adrian@tailscale.com>
This raises the maximum DNS response message size from 512 to 4095. This
should be large enough for almost all situations that do not need TCP.
We still do not recognize EDNS, so we will still forward requests that
claim support for a larger response size than 4095 (that will be solved
later). For now, when a response comes back that is too large to fit in
our receive buffer, we now set the truncation flag in the DNS header,
which is an improvement from before but will prompt attempts to use TCP
which isn't supported yet.
On Windows, WSARecvFrom into a buffer that's too small returns an error
in addition to the data. On other OSes, the extra data is silently
discarded. In this case, we prefer the latter so need to catch the error
on Windows.
Partially addresses #1123
Signed-off-by: Adrian Dewhurst <adrian@tailscale.com>
The cyolosecurity fork of certstore did not update its module name and
thus can only be used with a replace directive. This interferes with
installing using `go install` so I created a tailscale fork with an
updated module name.
Signed-off-by: Adrian Dewhurst <adrian@tailscale.com>
When searching for the matching client identity, the returned
certificate chain was accidentally set to that of the last identity
returned by the certificate store instead of the one corresponding to
the selected identity.
Also, add some extra error checking for invalid certificate chains, just
in case.
Signed-off-by: Adrian Dewhurst <adrian@tailscale.com>
control/controlclient: sign RegisterRequest
Some customers wish to verify eligibility for devices to join their
tailnets using machine identity certificates. TLS client certs could
potentially fulfill this role but the initial customer for this feature
has technical requirements that prevent their use. Instead, the
certificate is loaded from the Windows local machine certificate store
and uses its RSA public key to sign the RegisterRequest message.
There is room to improve the flexibility of this feature in future and
it is currently only tested on Windows (although Darwin theoretically
works too), but this offers a reasonable starting place for now.
Updates tailscale/coral#6
Signed-off-by: Adrian Dewhurst <adrian@tailscale.com>
This is a repeat of commit 3aa68cd397
which was lost in a rework of version.sh.
git worktrees have a .git file rather than a .git directory, so building
in a worktree caused version.sh to generate an error.
Signed-off-by: Adrian Dewhurst <adrian@tailscale.com>
Adrian DewhurstandAdrian Dewhurst
