Overwrite boringSSL's default key exchange preferences with safe
defaults using feature flags:
* "kx-pq-supported" enables support for PQ key exchange algorithms.
Classical key exchange is still preferred, but will be upgraded to PQ
if requested.
* "kx-pq-preferred" enables preference for PQ key exchange,
with fallback to classical key exchange if requested.
* "kx-nist-required" disables non-NIST key exchange.
Each feature implies "kx-safe-default". When this feature is enabled,
don't compile bindings for `SSL_CTX_set1_curves()` and `SslCurve`. This
is to prevent the feature flags from silently overriding curve
preferences chosen by the user.
Ideally we'd allow both: that is, use "kx-*" to set defaults, but still
allow the user to manually override them. However, this doesn't work
because by the time the `SSL_CTX` is constructed, we don't yet know
whether we're the client or server. (The "kx-*" features set different
preferences for each.) If "kx-sfe-default" is set, then the curve
preferences are set just before initiating a TLS handshake
(`SslStreamBuilder::connect()`) or waiting for a TLS handshake
(`SslStreamBuilder::accept()`).
* Add rerun-if-env-changed instructions for BORING_* variables
* Use X509_get0_notBefore() and X509_get0_notAfter() instead of X509_getm_notBefore() and X509_getm_notAfter().
According to
https://www.openssl.org/docs/man1.1.0/man3/X509_getm_notBefore.html,
"X509_getm_notBefore() and X509_getm_notAfter() are similar to
X509_get0_notBefore() and X509_get0_notAfter() except they return
non-constant mutable references to the associated date field of the
certificate".
* Only update boringssl submodule if BORING_BSSL_PATH not provided
* Allow BORING_BSSL_LIB_PATH to control link search
* Add fips feature
* Use X509_set_notAfter unconditionally for FIPS compatibility
This is equivalent according to
https://boringssl.googlesource.com/boringssl/+/c947efabcbc38dcf93e8ad0e6a76206cf0ec8072
The version of boringssl that's FIPS-certified doesn't have `X509_set1_notAfter`.
The only difference between that and `X509_set_notAfter` is whether they're const-correct,
which doesn't seem worth having two different code-paths.
* Check out fips commit automatically
* Verify the version of the compiler used for building boringssl
NIST specifies that it needs to be 7.0.1; I originally tried building with clang 10 and it failed.
Theoretically this should check the versions of Go and Ninja too, but they haven't given me trouble in practice.
Example error:
```
Compiling boring-sys v1.1.1 (/home/jnelson/work/boring/boring-sys)
error: failed to run custom build command for `boring-sys v1.1.1 (/home/jnelson/work/boring/boring-sys)`
Caused by:
process didn't exit successfully: `/home/jnelson/work/boring/target/debug/build/boring-sys-31b8ce53031cfd83/build-script-build` (exit status: 101)
--- stdout
cargo:rerun-if-env-changed=BORING_BSSL_PATH
--- stderr
warning: missing clang-7, trying other compilers: Permission denied (os error 13)
warning: FIPS requires clang version 7.0.1, skipping incompatible version "clang version 10.0.0-4ubuntu1 "
thread 'main' panicked at 'unsupported clang version "cc (Ubuntu 9.3.0-17ubuntu1~20.04) 9.3.0": FIPS requires clang 7.0.1', boring-sys/build.rs:216:13
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
```
* Add Github actions workflow testing FIPS
Co-authored-by: Joshua Nelson <jnelson@cloudflare.com>
This ensures that all the Rust functions, types and constants
always match the actual BoringSSL definitions.
It also removes quite a lot of manually maintained code, as well
as the need for systest.
The value for `SslOptions::ALL`, for example, was wrong. On current
BoringSSL versions, this is a no-op, and is set to `0`.
Clearing it does nothing. So, the `clear_ctx_options` test, that
passed by accident, was adjusted to use a different option.
The `libc` crate is not required, as we only use it for types that
are already defined in the standard library. It was removed from
`boring-sys`. The same can be done to other crates later.
Anthony Ramine