L46: C-core: New TLS Credentials API #422
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L46-core-tls-credential-API.md
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| // (in the one-side TLS scenario, the server is not required to provide root | ||
| // certs). We don't support default root certs on server side. | ||
| void watch_root_certs(); | ||
| // Sets the name of root certificates being watched, if |watch_root_certs| is |
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Pinging this so we don't lose it.
| ~TlsCustomVerificationCheckRequest() {} | ||
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| absl::string_view target_name() const; | ||
| absl::string_view peer_cert() const; |
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I think that comment is another signal that this API is not useful for anyone since they cannot really predict what the return value should be. I think we should probably deprecate + delete this API and replace it with APIs that return predictable and explicit values.
| // Sets the certificate verifier. The certificate verifier performs checks on | ||
| // the peer certificate chain after the chain has been (cryptographically) | ||
| // verified to chain up to a trusted root. | ||
| // If unset, this will default to the `HostNameCertificateVerifier` detailed |
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Should it only do this default on the client-side?
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That's a good question - I think it depends on other defaults, and if we are doing MTLS vs. TLS? I'll double check, but I don't believe this is called unless it is configured to do MTLS.
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I'm not sure that's correct. For example, we want it to default to the HostnameVerifier on the client-side even when we are doing (normal) TLS only.
L46-core-tls-credential-API.md
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| // identity certificates(single side TLS). | ||
| class TlsChannelCredentialsOptions final : public TlsCredentialsOptions { | ||
| public: | ||
| // Sets the decision of whether to do a crypto check on the server certs. |
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Despite the other comment, I think we need to clean up this comment so that it is more precise. :)
| ~TlsCustomVerificationCheckRequest() {} | ||
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| absl::string_view target_name() const; | ||
| absl::string_view peer_cert() const; |
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How do we get a verified chain on resumed handshakes?
| // Sets the certificate verifier. The certificate verifier performs checks on | ||
| // the peer certificate chain after the chain has been (cryptographically) | ||
| // verified to chain up to a trusted root. | ||
| // If unset, this will default to the `HostNameCertificateVerifier` detailed |
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I'm not sure that's correct. For example, we want it to default to the HostnameVerifier on the client-side even when we are doing (normal) TLS only.
| ~TlsCustomVerificationCheckRequest() {} | ||
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| absl::string_view target_name() const; | ||
| absl::string_view peer_cert() const; |
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Ya that's what I was hinting at. Resumed handshakes skip the cryptographic verification, but I'm not sure if they skip the post-handshake verification. If that's correct, we need to explain that some of these fields may not be available on resumed handshakes.
| ```c++ | ||
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| class UnverifiedPeerChain { |
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micro-nit: s/PeerChain/PeerCertificateChain
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| class UnverifiedPeerChain { | ||
| std::vector<absl::string_view> peer_cert_chain_der; |
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nit: absl::Span instead of std::vector?
| public: | ||
| virtual ~CustomChainBuilderInterface() = default; | ||
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| // Performs custom chain building. gRPC invokes this function. When Chain |
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nit: Consider omitting "gRPC invokes this function.", as I don't think it adds anything.
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| virtual ~CustomChainBuilderInterface() = default; | ||
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| // Performs custom chain building. gRPC invokes this function. When Chain |
| ``` | ||
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| The default behavior for chain building is to defer to the underlying SSL library, which has a built-in chain building API that has been hardened over many years of use with the web PKI. For example, [X509_verify_cert](https://www.openssl.org/docs/man1.1.1/man3/X509_verify_cert.html) is the implementation in OpenSSL that builds a chain and verifies that it is trusted by one of the root certificates. | ||
| One use case for the custom chain building feature is to enable SPIFFE federation (TODO: ref the SPIFFE spec), where the set of root certificates to use is determined based on the SPIFFE trust domain in the peer's leaf certificate. |
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nit: Please address this TODO.
| FileWatcherCertificateProvider(absl::string_view private_key_path, | ||
| absl::string_view identity_certificate_path, | ||
| absl::string_view root_cert_path, | ||
| unsigned int refresh_interval_sec); |
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micro-nit: Prefer absl::Duration here and below rather than using an unsigned int to represent time.
| public: | ||
| // Sets the decision of whether to do a crypto check on the server certificates. | ||
| // The default is true. | ||
| void set_verify_server_certificates(bool verify_server_certs); |
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We need e.g. "insecure" in the name here.
This PR is subsuming the previous PR of the same title (#205), and attempting to bring the content to the current state with the goal of formally merging this and moving these API from experimental to stable.
This is still under active work and is not ready for final review.