In commit 2aaf6bb6e9, an issue was fixed where
systemd-resolved could get stuck for multiple seconds waiting for incoming data,
since GnuTLS/OpenSSL can buffer a TLS record, so data could be available, but
no EPOLLIN event would be generated.
To fix this, a somewhat elaborate logic consisting on asking the TLS library
whether it had buffered data, then "faking" an EPOLLIN event was implemented.
However, there is a much simpler solution: Always read as much data as available
(i.e. until we get an event like EAGAIN when trying to read) from the stream
when we get an EPOLLIN event, instead of at most a single packet per event.
This approach does not require asking the TLS library whether it has buffered
data, and the logic is exactly the same for both the TCP and TLS case.
test-resolved-stream is fixed to avoid a latent double free bug.
When sending multiple DNS questions to a DNS-over-TLS server (e.g. a question
for A and AAAA records, as is typical) on the same session, the server may
answer to each question in a separate TLS record, but it may also aggregate
multiple answers in a single TLS record.
(Some servers do this very often (e.g. Cloudflare 1.0.0.1), some do it sometimes
(e.g. Google 8.8.8.8) and some seem to never do it (e.g. Quad9 9.9.9.10)).
Both cases should be handled equivalently, as the byte stream is the same, but
when multiple answers came in a single TLS record, usually the first answer was
processed, but the second answer was entirely ignored, which caused a 10s delay
until the resolution timed out and the missing question was retried.
This can be reproduced by configuring one of the offending server and running
`resolvectl query google.com --cache=no` a few times.
To be notified of incoming data, systemd-resolved listens to `EPOLLIN` events
on the underlying socket. However, when DNS-over-TLS is used, the TLS library
(OpenSSL or GnuTLS) may read and buffer the entire TLS record when reading the
first answer, so usually no further `EPOLLIN` events will be generated, and the
second answer will never be processed.
To avoid this, if there's buffered TLS data, generate a "fake" EPOLLIN event.
This is hacky, but it makes this case transparent to the rest of the IO code.
Getting certificates for dm-verity roothash signing into the trusted
kernel keychain is a royal PITA (means recompiling or rebooting with
shim), hence let's add a minimal userspace PKCS7 validation as well.
The mechanism is really simple and compatible with the verification the
kernel does. The only difference is that the certificates are searched
in /etc/verity.d/*.crt (and similar dirs in /usr/lib/, …).
We'll first try validation by passing the PKCS#7 data to the kernel, but
if that doesn't work we'll see if one of the certificates found that way
works and then attempt to attach the image without passing the PKCS#7
data to the kernel.
This makes it very easy to have fully validated GPT disk images. For
example, just copy the 'mkosi.secure-boot.crt' file you have in your
mkosi build dir to /etc/verity.d/ and things should just work.
Widely accepted certificates for IP addresses are expensive and only
affordable for larger organizations. Therefore if the user provides
the hostname in the DNS= option, we should use it instead of the IP
address.
Instead of having a context and/or trusted CA list per server this is now moved to the server. Ensures future TLS configuration options are global instead of per server.
This reverts commit 18bddeaaf2.
Revert this because it does not take the OpenSSL internal read pointer
into considoration. Resulting in padding in packetdata and therefore
broken SSL connections.
Ideally, coccinelle would strip unnecessary braces too. But I do not see any
option in coccinelle for this, so instead, I edited the patch text using
search&replace to remove the braces. Unfortunately this is not fully automatic,
in particular it didn't deal well with if-else-if-else blocks and ifdefs, so
there is an increased likelikehood be some bugs in such spots.
I also removed part of the patch that coccinelle generated for udev, where we
returns -1 for failure. This should be fixed independently.
To decreae latency this add support for TFO and TLS Session Tickets. As OpenSSL wouldn't let you easily set a different function all written data is temporarily cached and therefore needs to be flushed after each SSL function which can write data.
This provides basic OpenSSL support without optimizations like TCP Fast Open and TLS Session Tickets.
Notice only a single SSL library can be enabled at a time and therefore journald functions provided by GnuTLS will be disabled when using OpenSSL.
Fixes#9531
Joan Bruguera
Lennart Poettering
Benjamin Robin
Yu Watanabe
Daan De Meyer
Jörg Thalheim
Guilhem Lettron
Iwan Timmer
Tomas Mraz
Aleksei Timofeyev
Zbigniew Jędrzejewski-Szmek