external/boringssl: Sync to 7a817f48bafee508b2d23ad278f892ee1cb32b91.

Re-lands https://r.android.com/1774909

This includes the following changes:

https://boringssl.googlesource.com/boringssl/+log/ae2bb641735447496bed334c495e4868b981fe32..7a817f48bafee508b2d23ad278f892ee1cb32b91

* Add 'generate-ech' command to bssl tool
* Don't enable atomics in NO_THREADS configurations.
* Check strtoul return for overflow error in GetUnsigned()
* Add convenience functions to malloc EVP_HPKE_CTX and EVP_HPKE_KEY.
* Document that SSL_PRIVATE_KEY_METHOD should configure signing prefs.
* Always have CRYPTO_sysrand_for_seed.
* hrss: use less stack space.
* Make X509_EXTENSION opaque.
Update-Note: Use X509_EXTENSION_get_* instead.
* Make X509_CRL opaque.
Update-Note: Use accessors instead.
* Switch another malloc to bssl::Array.
* Add a pointer alignment helper function.
* Remove unused field in X509_NAME_ENTRY.
Update-Note: Removed unused field in struct.
* Fix sign bit in BN_div if numerator and quotient alias.
* Handle the server case in SSL_get0_ech_name_override.
* Remove -2 return value from X509*_get_*_by_NID.
Update-Note: The return value convention of some functions was
simplified. This is not expected to affect any callers.
* Remove X509at_get0_data_by_OBJ.
Update-Note: X509at_get0_data_by_OBJ is removed. We found no callers of
this function.
* Document a batch of extension-related functions in x509.h.
* conf: fix getting keys from the default section.
* conf: don't crash when parsing.
* Add some OpenSSL compatibility aliases.
* Make ASN1_OBJECT opaque.
Update-Note: ASN1_OBJECT is now opaque. Callers should use accessors.
* Rename asn1_locl.h to internal.h.
* Update hpke_test.go.
* Decorate x509v3_a2i_ipadd declaration as its definition.
* SHA-256 is used on AArch64, even if NO_ASM.
* swtb is another AArch64 magic tweak.
* Implement ClientHelloOuter handshakes.
* runner: Add a convenience function for base64 flags.
* Reduce bouncing on the cache lock in ssl_update_cache.
Update-Note: This reshuffles some locks around the session cache.
(Hopefully for the better.)
* Only clear not_resumable after the handshake.
* runner: Test that clients actually use renewed tickets.
* runner: Clean up test logic.
* runner: Fix process exit timeout.
* Remove old ASN.1 SET macros.
* Document some ASN1_INTEGER and ASN1_ENUMERATED functions.
* Document ASN1_STRING_to_UTF8.
* Const-correct ASN1_item_verify a bit more.
* Compute ASN.1 BIT STRING sizes more consistently.
* Remove lh_FOO_doall.
* Prefix internal LHASH functions.
* Unexport almost all of LHASH.
Update-Note: BoringSSL no longer provides a general-purpose hash table
to callers. Use the language's standard library, or another
implementation.
* Rename t1_lib.cc to extensions.cc.
* Prefix and unexport a2i_ipadd.
* Fix a -Wdeprecated-copy warning.
* Validate ECH public names.
* Fold X509_VERIFY_PARAM_ID into X509_VERIFY_PARAM.
* Make X509_VERIFY_PARAM opaque.
Update-Note: Use setters instead of configuring X509_VERIFY_PARAM
directly.
* Move crypto/x509/vpm_int.h into internal.h.
* Reformat x509_vfy.h and convert comments.
* Reland "Add util/fetch_ech_config_list.go"
* Revert "Add util/fetch_ech_config_list.go"
* Add util/fetch_ech_config_list.go
* More reliably report handshake errors through SSL_write.
* Add an option to permute ClientHello extension order.
* runner: Check the test name against the protocol being tested.
* Remove outdated comment in primality testing.
* Add most of an ECH client implementation.
* Add a basic API to make ECHConfigs.
* Make ECH server APIs take EVP_HPKE_KEY.
* Rename SSL_ECH_SERVER_CONFIG_LIST to SSL_ECH_KEYS.
* runner: Self-check tests more accurately and earlier.
* Don't pad the second ClientHello.
* Fix ext_pre_shared_key_clienthello_length calculation.
* Tidy up the PSK binder logic.
* Move the TLS vs DTLS header length adjustment into ssl_add_clienthello_tlsext.
* Shift some complexity out of ssl_add_clienthello_tlsext.
* Add a note about extension callback names.
* Add move support to EVP_MD_CTX.
* Replace hs->needs_psk_binder with an output parameter.
* Make add_clienthello callbacks const.
* Fix documentation typo.
* Compute the ECH GREASE payload outside of the callbacks.
* Pick up the GREASE ECH config ID from grease_seed.
* Initialize grease_seed on construction.
* Remove the extension init hook.
* Move key_share computation out of ClientHello callbacks.
* Release some temporaries outside of ClientHello callbacks.
* Move the early_data_{offered,reason} logic out of extension callbacks.
* Implement a handshake hint for certificate compression.
* runner: Implement ECH server for testing.
* runner: Parse the status_request extension more strictly.
* runner: Make echIsInner a boolean.
* runner: Revise ECHConfig type in preparation for client implementation
* Fix ECH-Server-RepeatedConfigID test.
* Add SSL_ech_accepted API and ech_is_required alerts.
* Reject the ECH extension in TLS 1.2 ServerHello.
* Move ECH-related APIs to encrypted_client_hello.cc.
* Const-correct message creation hooks.
* Remove the Channel ID callback.
Update-Note: SSL_CTX_set_channel_id_cb is removed.
SSL_set_tls_channel_id_enabled no longer enables Channel ID as a client,
only as a server.
* Manage Channel ID handshake state better.
Update-Note: SSL_get_tls_channel_id will no longer return all zeros
during the handshake or on the client. I did not find any callers
relying on this.
* DTLS-SRTP is only defined for DTLS.
* Remove impossible ssl->s3 null check.
* fix #415: Perl scripts fail when building from a path with spaces
* Cite an RFC over 9000 (draft-ietf-quic-tls is now RFC 9001).
Update-Note: QUIC APIs now default to the standard code point rather
than the draft one. QUICHE has already been calling
SSL_set_quic_use_legacy_codepoint, so this should not affect them. Once
callers implementing the draft versions cycle out, we can then drop
SSL_set_quic_use_legacy_codepoint altogether. I've also bumped
BORINGSSL_API_VERSION in case we end up needing an ifdef.
* Add compatibility impl for EVP_PKEY_get0
* Make md32_common.h single-included and use an unsized helper for SHA-256.
* Pull HASH_TRANSFORM out of md32_common.h.
* Ensure name not null in EVP_get_cipherbyname
* Fix array-parameter warnings
* Don't copy client's session ID into server's session.
* Test ECH server with unique and repeated config IDs.
* Refresh SSL corpora after adding ECH fuzzer mode.
* Implement fuzzer mode for ECH server.
* Don't try to write empty early data in the tool.
* GREASE is now RFC 8701.
* runner: Reject all zero client and server randoms.
* Const-correct SSL_get_srtp_profiles.
Update-Note: The change to the return type isn't quite compatible, but I
only found one caller of this function, which has since been fixed. (If
we need to return a non-const value for compatibility, we can do that
and document that the caller should not mutate the output.)
* Update the ECH GREASE size selection.
* fuzz/minimise_corpora.sh: Add shebang and chmod +x
* Add a missing case to SSL_error_description.
* Remove draft tokbind implementation.
Update-Note: Token binding APIs are removed.
* Make X509_REQ and X509_REQ_INFO opaque.
Update-Note: Callers that reach into X509_REQ and X509_REQ_INFO must use
accessors instead.
* Check hs->early_session, not ssl->session, for the early data limit.
* Fix some includes.
* Be clearer which signing inputs are digests.
* Validate RSA public keys more consistently.
Update-Note: See above.
* Add APIs to manually fill in signatures for CRLs.
* Check for resumption identifiers in SSL_SESSION_is_resumable.
* Don't use SHA256(ticket) as the signaling session ID for tickets.
* Simplify renego + resumption handling.
* Move session ID assignment out of ssl_get_new_session.
* Fix the ech_accept comment.
* Export the HPKE implementation.
* Refer to EVP_HPKE_CTX by a consistent name.
* Shift the KEM dependency in HPKE up a step.
* Update ACVP URLs.
* Add SSL_can_release_private_key.
* Make X509_SIG and X509_CERT_AUX opaque.
Update-Note: Direct access of these structs should be replaced by
accessors.
* acvp: move hash iterations into modulewrapper.
* Switch HPKE to a three-parameter output buffer.
* Introduce EVP_HPKE_{AEAD,KDF} types.
* Don't mark up the first word in a collective comment.
* Revise the deterministic for_test variant of HPKE's SetupBaseS.
* Fix a memory leak with d2i_ASN1_OBJECT object reuse.
* Remove HPKE PSK mode.
* Remove HKDF-SHA384 and HKDF-SHA512 from HPKE.
* Correctly order PKCS#7 certificates and CRLs.
Update-Note: It is no longer the case that constructing a PKCS#7 file
and parsing them back out will keep the certificates and CRLs in the
same order.
* Implement ECH draft 10 and update HPKE to draft 08.
* Document expected use of BTI and PAC macros.
* Remove non-deterministic bits from ECDSA ACVP test.
* Reference the newer ChaCha20-Poly1305 RFC.
* Use passive entropy collection everywhere.
* Rename X509V*_VERSION constants.
Update-Note: This renames some BoringSSL-specific constants that we
recently added. It doesn't look like anyone's used them yet.
* Const-correct ASN1_OBJECT_create.
* Clarify OBJ_get0_data and OBJ_get_length.
* avcp: SHA-1 for ECDSA _verification_ is still supported by NIST.
* A couple of Aarch64 FIPS delocate fixes.
* Use a placeholder for unknown errors in ERR_*_error_string.
* Include assembly optimizations in Bazel builds on Linux-aarch64.
* Remove some BoringSSL-only X509_CINF functions.
Update-Note: X509_get_cert_info, X509_CINF_set_modified, and
X509_CINF_get_signature are removed. I believe all callers have been
updated. Callers should use i2d_re_X509_tbs, i2d_X509_tbs, and
X509_get0_tbs_sigalg instead.
* Document and test X509_ATTRIBUTE creation functions.
* Revert handshaker fd numbers and make StartProcess more flexible.
* Remove support for malformed X509_ATTRIBUTEs.
Update-Note: Given OpenSSL hasn't accepted these for five years, it's
unlikely anything depends on it. If something breaks, we can revert this
and revisit. No one calls X509_ATTRIBUTE_set1_data on a non-empty
X509_ATTRIBUTE, so the behavior change there should be safe.
* Make X509_ATTRIBUTE opaque.
Update-Note: Direct accesses of X509_ATTRIBUTE should be replaced with
one of the accessors. I couldn't find any direct accesses, so hopefully
this is fine.
* acvptool: Fix typo hard-coding the HTTP method.
* Document a few more x509.h functions.
* Make X509_PUBKEY opaque.
Update-Note: Direct accesses of X509_PUBKEY should be replaced with one
of the accessors. I believe all callers have been fixed at this point.
* Always encode booleans as DER.
Update-Note: Callers setting ASN1_BOOLEANs to a positive value other
than 0xff will now encode 0xff. This probably fixes a bug, but if anyone
was attaching significance to incorrectly-encoded booleans, that will
break.
* Fix issuerUID and subjectUID parsing in the key usage checker.
* Add experimental handshake hints API.
* Make our Python scripts Python-3-compatible.
* Export ssl_client_hello_init for fuzzers.
* acvp: support GMAC as an algorithm.
* Record a fuzzing corpus for the ClientHelloInner decoder.
* Use a consistent plural for 'corpus'.
* Add util/bot/libFuzzer to .gitignore.
* acvp: support KAS-ECC-SSC staticUnified mode.
* Check for invalid ALPN inputs in SSL_(CTX_)set_alpn_protos.
Update-Note: SSL_CTX_set_alpn_protos and SSL_set_alpn_protos will now
reject invalud inputs. Previously, they would accept them, but silently
send an invalid ALPN extension which the server would almost certainly
error on.
* Don't duplicate ServerHello construction code.
* Rearrange key share and early data logic.
* Only skip early data with HRR when offered.
* Add ECH server config API to ssl_ctx_api fuzzer
* Fix ppc64le build.
* Simplify the Lucky13 mitigation.
* Add ECH server (draft-ietf-tls-esni-09).
* runner: Remove unused field
* runner: Construct finishedHash earlier.
* Simplify tls_cbc.c slightly.
* Remove remnants of CBC SHA2 cipher suites.
* runner: Test different V2ClientHello challenge lengths.
* runner: Ensure helloBytes is always the same as hello.marshal().
* runner: Fix ECH confirmation calculation with PSKs in tests.
* runner: Fix HPKE parameter order.
* runner: UpdateForHelloRetryRequest cannot fail.
* runner: Don't use the buffer in TLS 1.3.
* runner: Don't maintain two copies of the same transcript hash.
* runner: Remove remnants of SSL 3.0.
* runner: Fix writeClientHash and writeRecord ordering.
* runner: Remove CheckTLS13DowngradeRandom.
* runner: Remove remnants of the separate HelloRetryRequest message.
* runner: Store a cipherSuite in ClientSessionState.
* runner: Move writeHash to the finishedHash struct.
* Fix the spelling of HPKE AEAD constants.
* Don't reset server callback expectations on new handshake.
* Fix MockQuicTransport::Flush error handling.
* Fold ripemd/internal.h into ripemd.c.
* Move load/store helpers to crypto/internal.h.
* Make words in crypto/fipsmodule/modes actually words.
* Handle EINTR more in handshaker.cc.
* Add a few missing SSL_R_BIO_NOT_SET cases.
* Fix some unreachable code in the QUIC handshaker driver.
* Rearrange SSLKeyShare::Serialize.
* Fix ssl/internal.h sectioning.
* Remove some now unnecessary test exclusions from split handshakes.
* Remove tls13-split-handshakes flag.
* Define HANDSHAKER_SUPPORTED in once place.
* Tidy up handshaker tester.
* modulewrapper: add option to print build information.
* FIPS counters for AES-CTR.
* Enforce that pre_shared_key must come with psk_key_exchange_modes.
* Zero out FIPS counters.
* Remove is_resume field on TestState.
* Remove OPENSSL_DANGEROUS_RELEASE_PTHREAD_KEY build flag.
* Add some warnings on how to use OPENSSL_memory_* functions.
* Use an unsized helper for truncated SHA-512 variants.
Update-Note: There is a small chance the asserts will trip something,
but hopefully not since I've left SHA512_Final alone.
* Fix mismatch between header and implementation of bn_sqr_comba8.
* Remove GCC 4.8.99 check.
* Bump minimum CMake version.
* Automatically enable C11 atomics when available.
Update-Note: If something fails to compile, we'll revert this and adjust
the check, or add an opt-out, or give up. Also, if building with
-std=c99, consider -std=c11.
* Make generate_build_files.py python3 compatible.
* Remove X509_REQ_set_extension_nids and document related functions.
Update-Note: This removes a pair of unused functions.
* Document a few more functions in x509.h.
* Do not access value.ptr with V_ASN1_BOOLEAN.
* Add X509_PUBKEY_get0_public_key.
* Test empty EVP_CIPHER inputs and fix exact memcpy overlap.
* Revert "Implement rsa_pkcs1_sha256_legacy."
* Fix unnecessarily direction-specific tests in cipher_tests.txt
* Refactor HPKE API to include explicit length parameters.
* Generalize make_errors.go to allow EVP covering multiple directories.
* Add a Windows no-op impl of BORINGSSL_self_test
* Only pass -handshaker-path in split handshakes tests.
* Add RNG support for FreeBSD.
* Move fips.c into a subdirectory.
* Implement rsa_pkcs1_sha256_legacy.
* Better document nullable X.509 getters.
* runner: Remove redundant -enable-all-curves shim flag.
* Initialize nonce in PerAEADTest.ABI.
* Document ASN1_TYPE and related functions.
* fips: add counters.
* Align with OpenSSL on constness of static ASN1_OBJECTs.
Update-Note: The change to OBJ_nid2obj should be compatible. The changes
to X509_PUBKEY_set0_param and X509_ALGOR_set0 may require fixing some
pointer types.
* Add -rr-record flag to runner.go.
* Register NAME_CONSTRAINTS with bssl::UniquePtr.
* Register POLICY_MAPPING with bssl::UniquePtr.
* Stub out some more of PKCS7.
* Remove TODO to reverse the output of PKCS12_parse.
* Make the X509_VAL structure opaque.
Update-Note: I believe this is now safe to do. If there are compile
failures, switch to X509_get0_notBefore, X509_getm_notBefore, and
X509_set1_notBefore, or revert this if I'm wrong and too many callers
still need updating.
* Support creating unencrypted PKCS#12 files.
* Move PKCS#12 samples to embed_test_data.
* Remove some remnants of TLS 1.3 downgrade carveouts.
Update-Note:
https://boringssl-review.googlesource.com/c/boringssl/+/44124 made these
functions a no-op, but we kept them around because there were still some
call sites floating around. That code has since been updated, so we can
remove this.
* Remove X509_REQ_to_X509.
Update-Note: This removes a function that appears to be unused. It also
hardcodes the use of MD5, so please do not use it.
* Fix OPENSSL_EC_* constants and add EC_GROUP_get_asn1_flag
* RAND_set_rand_method returns int.
* Check the inner and outer CRL signature algorithms match.
Update-Note: Invalid CRLs with inconsistent inner and outer signature
algorithms will now be rejected.
* Remove block_mask from EVP_CIPHER_CTX.
Update-Note: It doesn't look like anyone is reading into this field. If
they are, we can ideally fix it, or revert this if absolutely necessary.
* Document a couple more functions in x509.h.
* Define X509V*_VERSION constants.
* Handle the default X.509 version explicitly.
* Compile for RISC-V.
* Add ECDSA nonce-testing functions.
* Rearrange ECDSA implementation.
* Split the FIPS mode PRNG lock in two.
* Remove legacy vs_toolchain.py environment variable.
* runner: Rename 'masterSecret' on session objects to plain 'secret'.
* Test ECDSA signing is non-deterministic.
* acvp: split ACVP modulewrapper for reuse by Trusty
* No-op CL to trigger some builds.
* Use CIPD Go packages.
* Update CMake on the bots and switch to CIPD where available.
* Future-proof vs_toolchain.py for VS2019.
* Revert "Revert "Disable check that X.509 extensions implies v3.""
* Update Clang and Go on the bots.
* Check for OBJ_nid2obj failures in X509_ATTRIBUTE_create.
* Don't overflow the output length in EVP_CipherUpdate calls.
Update-Note: Passing extremely large input lengths into EVP_CipherUpdate
will now fail. Use EVP_AEAD instead, which is size_t-based and has more
explicit output bounds.
* Remove X509_issuer_and_serial_hash.
Update-Note: No one uses this function. It had a NULL dereference in
some error cases. See CVE-2021-23841.
* Fix Bazel build breakage.
* Specify VS toolchain by command-line argument.
* Update Android Bazel build support in BUILD.toplevel.
* Honor SSL_TLSEXT_ERR_ALERT_FATAL in the ALPN callback.
Update-Note: Callers that return SSL_TLSEXT_ERR_ALERT_FATAL from the
ALPN callback will change behavior. The old behavior may be restored by
returning SSL_TLSEXT_ERR_NOACK, though see the documentation for new
recommendations on return values.
* acvp: detect header element in JSON.
* Align the ARM capability functions.
* Skip runtime NEON checks if __ARM_NEON is defined.
Update-Note: Builds with __ARM_NEON (-mfpu=neon) will now drop about
30KiB of dead code, but no longer work (if they even did before) on a
particular buggy CPU. Builds without __ARM_NEON are not affected.
* acvp: don't include CMAC-AES in regcap dump.
* acvp: fix CMAC verify
* Include bn/internal.h for non-bcm.c builds.
* Add various function calls to test_fips.
* Add missing include to self_check.c.
* Revert "Disable check that X.509 extensions implies v3."
* Fix TLS13SessionID-TLS13 test.

Test: atest CtsLibcoreTestCases CtsLibcoreOkHttpTestCases
Change-Id: Idb0a37fccba5d1c3f6a40fe91a81c5189170ed23

1 files changed, 435 insertions, 137 deletions

diff --git a/src/ssl/internal.h b/src/ssl/internal.h
index b3b75405..3b7326ae 100644
--- a/src/ssl/internal.h
+++ b/src/ssl/internal.h
@@ -152,7 +152,9 @@
 #include <utility>
 
 #include <openssl/aead.h>
+#include <openssl/curve25519.h>
 #include <openssl/err.h>
+#include <openssl/hpke.h>
 #include <openssl/lhash.h>
 #include <openssl/mem.h>
 #include <openssl/span.h>
@@ -161,6 +163,7 @@
 
 #include "../crypto/err/internal.h"
 #include "../crypto/internal.h"
+#include "../crypto/lhash/internal.h"
 
 
 #if defined(OPENSSL_WINDOWS)
@@ -276,9 +279,9 @@ class Array {
   T &operator[](size_t i) { return data_[i]; }
 
   T *begin() { return data_; }
-  const T *cbegin() const { return data_; }
+  const T *begin() const { return data_; }
   T *end() { return data_ + size_; }
-  const T *cend() const { return data_ + size_; }
+  const T *end() const { return data_ + size_; }
 
   void Reset() { Reset(nullptr, 0); }
 
@@ -378,6 +381,8 @@ class GrowableArray {
     return *this;
   }
 
+  const T *data() const { return array_.data(); }
+  T *data() { return array_.data(); }
   size_t size() const { return size_; }
   bool empty() const { return size_ == 0; }
 
@@ -385,9 +390,9 @@ class GrowableArray {
   T &operator[](size_t i) { return array_[i]; }
 
   T *begin() { return array_.data(); }
-  const T *cbegin() const { return array_.data(); }
+  const T *begin() const { return array_.data(); }
   T *end() { return array_.data() + size_; }
-  const T *cend() const { return array_.data() + size_; }
+  const T *end() const { return array_.data() + size_; }
 
   void clear() {
     size_ = 0;
@@ -484,15 +489,17 @@ bool ssl_get_version_range(const SSL_HANDSHAKE *hs, uint16_t *out_min_version,
                            uint16_t *out_max_version);
 
 // ssl_supports_version returns whether |hs| supports |version|.
-bool ssl_supports_version(SSL_HANDSHAKE *hs, uint16_t version);
+bool ssl_supports_version(const SSL_HANDSHAKE *hs, uint16_t version);
 
 // ssl_method_supports_version returns whether |method| supports |version|.
 bool ssl_method_supports_version(const SSL_PROTOCOL_METHOD *method,
                                  uint16_t version);
 
 // ssl_add_supported_versions writes the supported versions of |hs| to |cbb|, in
-// decreasing preference order.
-bool ssl_add_supported_versions(SSL_HANDSHAKE *hs, CBB *cbb);
+// decreasing preference order. The version list is filtered to those whose
+// protocol version is at least |extra_min_version|.
+bool ssl_add_supported_versions(const SSL_HANDSHAKE *hs, CBB *cbb,
+                                uint16_t extra_min_version);
 
 // ssl_negotiate_version negotiates a common version based on |hs|'s preferences
 // and the peer preference list in |peer_versions|. On success, it returns true
@@ -675,6 +682,9 @@ class SSLTranscript {
   SSLTranscript();
   ~SSLTranscript();
 
+  SSLTranscript(SSLTranscript &&other) = default;
+  SSLTranscript &operator=(SSLTranscript &&other) = default;
+
   // Init initializes the handshake transcript. If called on an existing
   // transcript, it resets the transcript and hash. It returns true on success
   // and false on failure.
@@ -696,9 +706,9 @@ class SSLTranscript {
   // the transcript. It returns true on success and false on failure. If the
   // handshake buffer is still present, |digest| may be any supported digest.
   // Otherwise, |digest| must match the transcript hash.
-  bool CopyToHashContext(EVP_MD_CTX *ctx, const EVP_MD *digest);
+  bool CopyToHashContext(EVP_MD_CTX *ctx, const EVP_MD *digest) const;
 
-  Span<const uint8_t> buffer() {
+  Span<const uint8_t> buffer() const {
     return MakeConstSpan(reinterpret_cast<const uint8_t *>(buffer_->data),
                          buffer_->length);
   }
@@ -721,14 +731,14 @@ class SSLTranscript {
   // GetHash writes the handshake hash to |out| which must have room for at
   // least |DigestLen| bytes. On success, it returns true and sets |*out_len| to
   // the number of bytes written. Otherwise, it returns false.
-  bool GetHash(uint8_t *out, size_t *out_len);
+  bool GetHash(uint8_t *out, size_t *out_len) const;
 
   // GetFinishedMAC computes the MAC for the Finished message into the bytes
   // pointed by |out| and writes the number of bytes to |*out_len|. |out| must
   // have room for |EVP_MAX_MD_SIZE| bytes. It returns true on success and false
   // on failure.
   bool GetFinishedMAC(uint8_t *out, size_t *out_len, const SSL_SESSION *session,
-                      bool from_server);
+                      bool from_server) const;
 
  private:
   // buffer_, if non-null, contains the handshake transcript.
@@ -1066,6 +1076,10 @@ class SSLKeyShare {
   // |Serialize|.
   static UniquePtr<SSLKeyShare> Create(CBS *in);
 
+  // Serializes writes the group ID and private key, in a format that can be
+  // read by |Create|.
+  bool Serialize(CBB *out);
+
   // GroupID returns the group ID.
   virtual uint16_t GroupID() const PURE_VIRTUAL;
 
@@ -1090,13 +1104,13 @@ class SSLKeyShare {
   virtual bool Finish(Array<uint8_t> *out_secret, uint8_t *out_alert,
                       Span<const uint8_t> peer_key) PURE_VIRTUAL;
 
-  // Serialize writes the state of the key exchange to |out|, returning true if
-  // successful and false otherwise.
-  virtual bool Serialize(CBB *out) { return false; }
+  // SerializePrivateKey writes the private key to |out|, returning true if
+  // successful and false otherwise. It should be called after |Offer|.
+  virtual bool SerializePrivateKey(CBB *out) { return false; }
 
-  // Deserialize initializes the state of the key exchange from |in|, returning
-  // true if successful and false otherwise.  It is called by |Create|.
-  virtual bool Deserialize(CBS *in) { return false; }
+  // DeserializePrivateKey initializes the state of the key exchange from |in|,
+  // returning true if successful and false otherwise.
+  virtual bool DeserializePrivateKey(CBS *in) { return false; }
 };
 
 struct NamedGroup {
@@ -1352,9 +1366,10 @@ bool ssl_on_certificate_selected(SSL_HANDSHAKE *hs);
 bool tls13_init_key_schedule(SSL_HANDSHAKE *hs, Span<const uint8_t> psk);
 
 // tls13_init_early_key_schedule initializes the handshake hash and key
-// derivation state from the resumption secret and incorporates the PSK to
-// derive the early secrets. It returns one on success and zero on error.
-bool tls13_init_early_key_schedule(SSL_HANDSHAKE *hs, Span<const uint8_t> psk);
+// derivation state from |session| for use with 0-RTT. It returns one on success
+// and zero on error.
+bool tls13_init_early_key_schedule(SSL_HANDSHAKE *hs,
+                                   const SSL_SESSION *session);
 
 // tls13_advance_key_schedule incorporates |in| into the key schedule with
 // HKDF-Extract. It returns true on success and false on error.
@@ -1407,25 +1422,184 @@ bool tls13_finished_mac(SSL_HANDSHAKE *hs, uint8_t *out, size_t *out_len,
 // on failure.
 bool tls13_derive_session_psk(SSL_SESSION *session, Span<const uint8_t> nonce);
 
-// tls13_write_psk_binder calculates the PSK binder value and replaces the last
-// bytes of |msg| with the resulting value. It returns true on success, and
-// false on failure.
-bool tls13_write_psk_binder(SSL_HANDSHAKE *hs, Span<uint8_t> msg);
+// tls13_write_psk_binder calculates the PSK binder value over |transcript| and
+// |msg|, and replaces the last bytes of |msg| with the resulting value. It
+// returns true on success, and false on failure. If |out_binder_len| is
+// non-NULL, it sets |*out_binder_len| to the length of the value computed.
+bool tls13_write_psk_binder(const SSL_HANDSHAKE *hs,
+                            const SSLTranscript &transcript, Span<uint8_t> msg,
+                            size_t *out_binder_len);
 
 // tls13_verify_psk_binder verifies that the handshake transcript, truncated up
 // to the binders has a valid signature using the value of |session|'s
 // resumption secret. It returns true on success, and false on failure.
-bool tls13_verify_psk_binder(SSL_HANDSHAKE *hs, SSL_SESSION *session,
-                             const SSLMessage &msg, CBS *binders);
+bool tls13_verify_psk_binder(const SSL_HANDSHAKE *hs,
+                             const SSL_SESSION *session, const SSLMessage &msg,
+                             CBS *binders);
+
+
+// Encrypted ClientHello.
+
+struct ECHConfig {
+  static constexpr bool kAllowUniquePtr = true;
+  // raw contains the serialized ECHConfig.
+  Array<uint8_t> raw;
+  // The following fields alias into |raw|.
+  Span<const uint8_t> public_key;
+  Span<const uint8_t> public_name;
+  Span<const uint8_t> cipher_suites;
+  uint16_t kem_id = 0;
+  uint16_t maximum_name_length = 0;
+  uint8_t config_id = 0;
+};
+
+class ECHServerConfig {
+ public:
+  static constexpr bool kAllowUniquePtr = true;
+  ECHServerConfig() = default;
+  ECHServerConfig(const ECHServerConfig &other) = delete;
+  ECHServerConfig &operator=(ECHServerConfig &&) = delete;
+
+  // Init parses |ech_config| as an ECHConfig and saves a copy of |key|.
+  // It returns true on success and false on error.
+  bool Init(Span<const uint8_t> ech_config, const EVP_HPKE_KEY *key,
+            bool is_retry_config);
+
+  // SetupContext sets up |ctx| for a new connection, given the specified
+  // HPKE ciphersuite and encapsulated KEM key. It returns true on success and
+  // false on error. This function may only be called on an initialized object.
+  bool SetupContext(EVP_HPKE_CTX *ctx, uint16_t kdf_id, uint16_t aead_id,
+                    Span<const uint8_t> enc) const;
+
+  const ECHConfig &ech_config() const { return ech_config_; }
+  bool is_retry_config() const { return is_retry_config_; }
+
+ private:
+  ECHConfig ech_config_;
+  ScopedEVP_HPKE_KEY key_;
+  bool is_retry_config_ = false;
+};
+
+enum ssl_client_hello_type_t {
+  ssl_client_hello_unencrypted,
+  ssl_client_hello_inner,
+  ssl_client_hello_outer,
+};
+
+// ssl_decode_client_hello_inner recovers the full ClientHelloInner from the
+// EncodedClientHelloInner |encoded_client_hello_inner| by replacing its
+// outer_extensions extension with the referenced extensions from the
+// ClientHelloOuter |client_hello_outer|. If successful, it writes the recovered
+// ClientHelloInner to |out_client_hello_inner|. It returns true on success and
+// false on failure.
+OPENSSL_EXPORT bool ssl_decode_client_hello_inner(
+    SSL *ssl, uint8_t *out_alert, Array<uint8_t> *out_client_hello_inner,
+    Span<const uint8_t> encoded_client_hello_inner,
+    const SSL_CLIENT_HELLO *client_hello_outer);
+
+// ssl_client_hello_decrypt attempts to decrypt the given |payload| into
+// |out_encoded_client_hello_inner|. The decrypted value should be an
+// EncodedClientHelloInner. It returns false if any fatal errors occur and true
+// otherwise, regardless of whether the decrypt was successful. It sets
+// |out_encoded_client_hello_inner| to true if the decryption fails, and false
+// otherwise.
+bool ssl_client_hello_decrypt(EVP_HPKE_CTX *hpke_ctx,
+                              Array<uint8_t> *out_encoded_client_hello_inner,
+                              bool *out_is_decrypt_error,
+                              const SSL_CLIENT_HELLO *client_hello_outer,
+                              uint16_t kdf_id, uint16_t aead_id,
+                              uint8_t config_id, Span<const uint8_t> enc,
+                              Span<const uint8_t> payload);
+
+#define ECH_CONFIRMATION_SIGNAL_LEN 8
+
+// ssl_ech_confirmation_signal_hello_offset returns the offset of the ECH
+// confirmation signal in a ServerHello message, including the handshake header.
+size_t ssl_ech_confirmation_signal_hello_offset(const SSL *ssl);
+
+// ssl_ech_accept_confirmation computes the server's ECH acceptance signal,
+// writing it to |out|. The signal is computed by concatenating |transcript|
+// with |server_hello|. This function handles the fact that eight bytes of
+// |server_hello| need to be replaced with zeros before hashing. It returns true
+// on success, and false on failure.
+bool ssl_ech_accept_confirmation(const SSL_HANDSHAKE *hs, Span<uint8_t> out,
+                                 const SSLTranscript &transcript,
+                                 Span<const uint8_t> server_hello);
+
+// ssl_is_valid_ech_public_name returns true if |public_name| is a valid ECH
+// public name and false otherwise. It is exported for testing.
+OPENSSL_EXPORT bool ssl_is_valid_ech_public_name(
+    Span<const uint8_t> public_name);
+
+// ssl_is_valid_ech_config_list returns true if |ech_config_list| is a valid
+// ECHConfigList structure and false otherwise.
+bool ssl_is_valid_ech_config_list(Span<const uint8_t> ech_config_list);
+
+// ssl_select_ech_config selects an ECHConfig and associated parameters to offer
+// on the client and updates |hs|. It returns true on success, whether an
+// ECHConfig was found or not, and false on internal error. On success, the
+// encapsulated key is written to |out_enc| and |*out_enc_len| is set to the
+// number of bytes written. If the function did not select an ECHConfig, the
+// encapsulated key is the empty string.
+bool ssl_select_ech_config(SSL_HANDSHAKE *hs, Span<uint8_t> out_enc,
+                           size_t *out_enc_len);
+
+// ssl_ech_extension_body_length returns the length of the body of a ClientHello
+// ECH extension that encrypts |in_len| bytes with |aead| and an 'enc' value of
+// length |enc_len|. The result does not include the four-byte extension header.
+size_t ssl_ech_extension_body_length(const EVP_HPKE_AEAD *aead, size_t enc_len,
+                                     size_t in_len);
+
+// ssl_encrypt_client_hello constructs a new ClientHelloInner, adds it to the
+// inner transcript, and encrypts for inclusion in the ClientHelloOuter. |enc|
+// is the encapsulated key to include in the extension. It returns true on
+// success and false on error. If not offering ECH, |enc| is ignored and the
+// function will compute a GREASE ECH extension if necessary, and otherwise
+// return success while doing nothing.
+//
+// Encrypting the ClientHelloInner incorporates all extensions in the
+// ClientHelloOuter, so all other state necessary for |ssl_add_client_hello|
+// must already be computed.
+bool ssl_encrypt_client_hello(SSL_HANDSHAKE *hs, Span<const uint8_t> enc);
+
+
+// Delegated credentials.
+
+// This structure stores a delegated credential (DC) as defined by
+// draft-ietf-tls-subcerts-03.
+struct DC {
+  static constexpr bool kAllowUniquePtr = true;
+  ~DC();
+
+  // Dup returns a copy of this DC and takes references to |raw| and |pkey|.
+  UniquePtr<DC> Dup();
+
+  // Parse parses the delegated credential stored in |in|. If successful it
+  // returns the parsed structure, otherwise it returns |nullptr| and sets
+  // |*out_alert|.
+  static UniquePtr<DC> Parse(CRYPTO_BUFFER *in, uint8_t *out_alert);
 
+  // raw is the delegated credential encoded as specified in draft-ietf-tls-
+  // subcerts-03.
+  UniquePtr<CRYPTO_BUFFER> raw;
 
-// Encrypted Client Hello.
+  // expected_cert_verify_algorithm is the signature scheme of the DC public
+  // key.
+  uint16_t expected_cert_verify_algorithm = 0;
 
-// tls13_ech_accept_confirmation computes the server's ECH acceptance signal,
-// writing it to |out|. It returns true on success, and false on failure.
-bool tls13_ech_accept_confirmation(
-    SSL_HANDSHAKE *hs, bssl::Span<uint8_t> out,
-    bssl::Span<const uint8_t> server_hello_ech_conf);
+  // pkey is the public key parsed from |public_key|.
+  UniquePtr<EVP_PKEY> pkey;
+
+ private:
+  friend DC* New<DC>();
+  DC();
+};
+
+// ssl_signing_with_dc returns true if the peer has indicated support for
+// delegated credentials and this host has sent a delegated credential in
+// response. If this is true then we've committed to using the DC in the
+// handshake.
+bool ssl_signing_with_dc(const SSL_HANDSHAKE *hs);
 
 
 // Handshake functions.
@@ -1440,7 +1614,6 @@ enum ssl_hs_wait_t {
   ssl_hs_handoff,
   ssl_hs_handback,
   ssl_hs_x509_lookup,
-  ssl_hs_channel_id_lookup,
   ssl_hs_private_key_operation,
   ssl_hs_pending_session,
   ssl_hs_pending_ticket,
@@ -1449,6 +1622,7 @@ enum ssl_hs_wait_t {
   ssl_hs_read_end_of_early_data,
   ssl_hs_read_change_cipher_spec,
   ssl_hs_certificate_verify,
+  ssl_hs_hints_ready,
 };
 
 enum ssl_grease_index_t {
@@ -1458,12 +1632,14 @@ enum ssl_grease_index_t {
   ssl_grease_extension2,
   ssl_grease_version,
   ssl_grease_ticket_extension,
-  ssl_grease_last_index = ssl_grease_ticket_extension,
+  ssl_grease_ech_config_id,
+  ssl_grease_last_index = ssl_grease_ech_config_id,
 };
 
 enum tls12_server_hs_state_t {
   state12_start_accept = 0,
   state12_read_client_hello,
+  state12_read_client_hello_after_ech,
   state12_select_certificate,
   state12_tls13,
   state12_select_parameters,
@@ -1515,46 +1691,30 @@ enum handback_t {
   handback_max_value = handback_tls13,
 };
 
-
-// Delegated credentials.
-
-// This structure stores a delegated credential (DC) as defined by
-// draft-ietf-tls-subcerts-03.
-struct DC {
+// SSL_HANDSHAKE_HINTS contains handshake hints for a connection. See
+// |SSL_request_handshake_hints| and related functions.
+struct SSL_HANDSHAKE_HINTS {
   static constexpr bool kAllowUniquePtr = true;
-  ~DC();
 
-  // Dup returns a copy of this DC and takes references to |raw| and |pkey|.
-  UniquePtr<DC> Dup();
+  Array<uint8_t> server_random;
 
-  // Parse parses the delegated credential stored in |in|. If successful it
-  // returns the parsed structure, otherwise it returns |nullptr| and sets
-  // |*out_alert|.
-  static UniquePtr<DC> Parse(CRYPTO_BUFFER *in, uint8_t *out_alert);
+  uint16_t key_share_group_id = 0;
+  Array<uint8_t> key_share_public_key;
+  Array<uint8_t> key_share_secret;
 
-  // raw is the delegated credential encoded as specified in draft-ietf-tls-
-  // subcerts-03.
-  UniquePtr<CRYPTO_BUFFER> raw;
+  uint16_t signature_algorithm = 0;
+  Array<uint8_t> signature_input;
+  Array<uint8_t> signature_spki;
+  Array<uint8_t> signature;
 
-  // expected_cert_verify_algorithm is the signature scheme of the DC public
-  // key.
-  uint16_t expected_cert_verify_algorithm = 0;
-
-  // pkey is the public key parsed from |public_key|.
-  UniquePtr<EVP_PKEY> pkey;
+  Array<uint8_t> decrypted_psk;
+  bool ignore_psk = false;
 
- private:
-  friend DC* New<DC>();
-  DC();
+  uint16_t cert_compression_alg_id = 0;
+  Array<uint8_t> cert_compression_input;
+  Array<uint8_t> cert_compression_output;
 };
 
-// ssl_signing_with_dc returns true if the peer has indicated support for
-// delegated credentials and this host has sent a delegated credential in
-// response. If this is true then we've committed to using the DC in the
-// handshake.
-bool ssl_signing_with_dc(const SSL_HANDSHAKE *hs);
-
-
 struct SSL_HANDSHAKE {
   explicit SSL_HANDSHAKE(SSL *ssl);
   ~SSL_HANDSHAKE();
@@ -1599,7 +1759,21 @@ struct SSL_HANDSHAKE {
  public:
   void ResizeSecrets(size_t hash_len);
 
+  // GetClientHello, on the server, returns either the normal ClientHello
+  // message or the ClientHelloInner if it has been serialized to
+  // |ech_client_hello_buf|. This function should only be called when the
+  // current message is a ClientHello. It returns true on success and false on
+  // error.
+  //
+  // Note that fields of the returned |out_msg| and |out_client_hello| point
+  // into a handshake-owned buffer, so their lifetimes should not exceed this
+  // SSL_HANDSHAKE.
+  bool GetClientHello(SSLMessage *out_msg, SSL_CLIENT_HELLO *out_client_hello);
+
   Span<uint8_t> secret() { return MakeSpan(secret_, hash_len_); }
+  Span<const uint8_t> secret() const {
+    return MakeConstSpan(secret_, hash_len_);
+  }
   Span<uint8_t> early_traffic_secret() {
     return MakeSpan(early_traffic_secret_, hash_len_);
   }
@@ -1621,7 +1795,7 @@ struct SSL_HANDSHAKE {
 
   union {
     // sent is a bitset where the bits correspond to elements of kExtensions
-    // in t1_lib.c. Each bit is set if that extension was sent in a
+    // in extensions.cc. Each bit is set if that extension was sent in a
     // ClientHello. It's not used by servers.
     uint32_t sent = 0;
     // received is a bitset, like |sent|, but is used by servers to record
@@ -1629,9 +1803,9 @@ struct SSL_HANDSHAKE {
     uint32_t received;
   } extensions;
 
-  // retry_group is the group ID selected by the server in HelloRetryRequest in
-  // TLS 1.3.
-  uint16_t retry_group = 0;
+  // inner_extensions_sent, on clients that offer ECH, is |extensions.sent| for
+  // the ClientHelloInner.
+  uint32_t inner_extensions_sent = 0;
 
   // error, if |wait| is |ssl_hs_error|, is the error the handshake failed on.
   UniquePtr<ERR_SAVE_STATE> error;
@@ -1644,15 +1818,30 @@ struct SSL_HANDSHAKE {
   // transcript is the current handshake transcript.
   SSLTranscript transcript;
 
+  // inner_transcript, on the client, is the handshake transcript for the
+  // ClientHelloInner handshake. It is moved to |transcript| if the server
+  // accepts ECH.
+  SSLTranscript inner_transcript;
+
+  // inner_client_random is the ClientHello random value used with
+  // ClientHelloInner.
+  uint8_t inner_client_random[SSL3_RANDOM_SIZE] = {0};
+
   // cookie is the value of the cookie received from the server, if any.
   Array<uint8_t> cookie;
 
-  // ech_grease contains the bytes of the GREASE ECH extension that was sent in
-  // the first ClientHello.
-  Array<uint8_t> ech_grease;
+  // ech_client_bytes contains the ECH extension to send in the ClientHello.
+  Array<uint8_t> ech_client_bytes;
 
-  // key_share_bytes is the value of the previously sent KeyShare extension by
-  // the client in TLS 1.3.
+  // ech_retry_configs, on the client, contains the retry configs from the
+  // server as a serialized ECHConfigList.
+  Array<uint8_t> ech_retry_configs;
+
+  // ech_client_hello_buf, on the server, contains the bytes of the
+  // reconstructed ClientHelloInner message.
+  Array<uint8_t> ech_client_hello_buf;
+
+  // key_share_bytes is the key_share extension that the client should send.
   Array<uint8_t> key_share_bytes;
 
   // ecdh_public_key, for servers, is the key share to be sent to the client in
@@ -1676,17 +1865,21 @@ struct SSL_HANDSHAKE {
   // peer_key is the peer's ECDH key for a TLS 1.2 client.
   Array<uint8_t> peer_key;
 
-  // negotiated_token_binding_version is used by a server to store the
-  // on-the-wire encoding of the Token Binding protocol version to advertise in
-  // the ServerHello/EncryptedExtensions if the Token Binding extension is to be
-  // sent.
-  uint16_t negotiated_token_binding_version;
+  // extension_permutation is the permutation to apply to ClientHello
+  // extensions. It maps indices into the |kExtensions| table into other
+  // indices.
+  Array<uint8_t> extension_permutation;
 
   // cert_compression_alg_id, for a server, contains the negotiated certificate
   // compression algorithm for this client. It is only valid if
   // |cert_compression_negotiated| is true.
   uint16_t cert_compression_alg_id;
 
+  // ech_hpke_ctx is the HPKE context used in ECH. On the server, it is
+  // initialized if |ech_status| is |ssl_ech_accepted|. On the client, it is
+  // initialized if |selected_ech_config| is not nullptr.
+  ScopedEVP_HPKE_CTX ech_hpke_ctx;
+
   // server_params, in a TLS 1.2 server, stores the ServerKeyExchange
   // parameters. It has client and server randoms prepended for signing
   // convenience.
@@ -1723,12 +1916,29 @@ struct SSL_HANDSHAKE {
   // the client if |in_early_data| is true.
   UniquePtr<SSL_SESSION> early_session;
 
+  // ssl_ech_keys, for servers, is the set of ECH keys to use with this
+  // handshake. This is copied from |SSL_CTX| to ensure consistent behavior as
+  // |SSL_CTX| rotates keys.
+  UniquePtr<SSL_ECH_KEYS> ech_keys;
+
+  // selected_ech_config, for clients, is the ECHConfig the client uses to offer
+  // ECH, or nullptr if ECH is not being offered. If non-NULL, |ech_hpke_ctx|
+  // will be initialized.
+  UniquePtr<ECHConfig> selected_ech_config;
+
   // new_cipher is the cipher being negotiated in this handshake.
   const SSL_CIPHER *new_cipher = nullptr;
 
   // key_block is the record-layer key block for TLS 1.2 and earlier.
   Array<uint8_t> key_block;
 
+  // hints contains the handshake hints for this connection. If
+  // |hints_requested| is true, this field is non-null and contains the pending
+  // hints to filled as the predicted handshake progresses. Otherwise, this
+  // field, if non-null, contains hints configured by the caller and will
+  // influence the handshake on match.
+  UniquePtr<SSL_HANDSHAKE_HINTS> hints;
+
   // ech_present, on the server, indicates whether the ClientHello contained an
   // encrypted_client_hello extension.
   bool ech_present : 1;
@@ -1737,13 +1947,13 @@ struct SSL_HANDSHAKE {
   // contained an ech_is_inner extension.
   bool ech_is_inner_present : 1;
 
+  // ech_authenticated_reject, on the client, indicates whether an ECH rejection
+  // handshake has been authenticated.
+  bool ech_authenticated_reject : 1;
+
   // scts_requested is true if the SCT extension is in the ClientHello.
   bool scts_requested : 1;
 
-  // needs_psk_binder is true if the ClientHello has a placeholder PSK binder to
-  // be filled in.
-  bool needs_psk_binder : 1;
-
   // handshake_finalized is true once the handshake has completed, at which
   // point accessors should use the established state.
   bool handshake_finalized : 1;
@@ -1805,15 +2015,17 @@ struct SSL_HANDSHAKE {
   // in progress.
   bool pending_private_key_op : 1;
 
-  // grease_seeded is true if |grease_seed| has been initialized.
-  bool grease_seeded : 1;
-
   // handback indicates that a server should pause the handshake after
   // finishing operations that require private key material, in such a way that
   // |SSL_get_error| returns |SSL_ERROR_HANDBACK|.  It is set by
   // |SSL_apply_handoff|.
   bool handback : 1;
 
+  // hints_requested indicates the caller has requested handshake hints. Only
+  // the first round-trip of the handshake will complete, after which the
+  // |hints| structure can be serialized.
+  bool hints_requested : 1;
+
   // cert_compression_negotiated is true iff |cert_compression_alg_id| is valid.
   bool cert_compression_negotiated : 1;
 
@@ -1821,6 +2033,14 @@ struct SSL_HANDSHAKE {
   // which implemented TLS 1.3 incorrectly.
   bool apply_jdk11_workaround : 1;
 
+  // can_release_private_key is true if the private key will no longer be used
+  // in this handshake.
+  bool can_release_private_key : 1;
+
+  // channel_id_negotiated is true if Channel ID should be used in this
+  // handshake.
+  bool channel_id_negotiated : 1;
+
   // client_version is the value sent or received in the ClientHello version.
   uint16_t client_version = 0;
 
@@ -1832,12 +2052,14 @@ struct SSL_HANDSHAKE {
   // record layer.
   uint16_t early_data_written = 0;
 
+  // ech_config_id is the ECH config sent by the client.
+  uint8_t ech_config_id = 0;
+
   // session_id is the session ID in the ClientHello.
   uint8_t session_id[SSL_MAX_SSL_SESSION_ID_LENGTH] = {0};
   uint8_t session_id_len = 0;
 
-  // grease_seed is the entropy for GREASE values. It is valid if
-  // |grease_seeded| is true.
+  // grease_seed is the entropy for GREASE values.
   uint8_t grease_seed[ssl_grease_last_index + 1] = {0};
 };
 
@@ -1897,14 +2119,24 @@ bool tls13_process_new_session_ticket(SSL *ssl, const SSLMessage &msg);
 bssl::UniquePtr<SSL_SESSION> tls13_create_session_with_ticket(SSL *ssl,
                                                               CBS *body);
 
+// ssl_setup_extension_permutation computes a ClientHello extension permutation
+// for |hs|, if applicable. It returns true on success and false on error.
+bool ssl_setup_extension_permutation(SSL_HANDSHAKE *hs);
+
+// ssl_setup_key_shares computes client key shares and saves them in |hs|. It
+// returns true on success and false on failure. If |override_group_id| is zero,
+// it offers the default groups, including GREASE. If it is non-zero, it offers
+// a single key share of the specified group.
+bool ssl_setup_key_shares(SSL_HANDSHAKE *hs, uint16_t override_group_id);
+
 bool ssl_ext_key_share_parse_serverhello(SSL_HANDSHAKE *hs,
                                          Array<uint8_t> *out_secret,
                                          uint8_t *out_alert, CBS *contents);
 bool ssl_ext_key_share_parse_clienthello(SSL_HANDSHAKE *hs, bool *out_found,
-                                         Array<uint8_t> *out_secret,
-                                         uint8_t *out_alert, CBS *contents);
-bool ssl_ext_key_share_add_serverhello(SSL_HANDSHAKE *hs, CBB *out,
-                                       bool dry_run);
+                                         Span<const uint8_t> *out_peer_key,
+                                         uint8_t *out_alert,
+                                         const SSL_CLIENT_HELLO *client_hello);
+bool ssl_ext_key_share_add_serverhello(SSL_HANDSHAKE *hs, CBB *out);
 
 bool ssl_ext_pre_shared_key_parse_serverhello(SSL_HANDSHAKE *hs,
                                               uint8_t *out_alert,
@@ -1919,7 +2151,17 @@ bool ssl_ext_pre_shared_key_add_serverhello(SSL_HANDSHAKE *hs, CBB *out);
 // returns whether it's valid.
 bool ssl_is_sct_list_valid(const CBS *contents);
 
-bool ssl_write_client_hello(SSL_HANDSHAKE *hs);
+// ssl_write_client_hello_without_extensions writes a ClientHello to |out|,
+// up to the extensions field. |type| determines the type of ClientHello to
+// write. If |omit_session_id| is true, the session ID is empty.
+bool ssl_write_client_hello_without_extensions(const SSL_HANDSHAKE *hs,
+                                               CBB *cbb,
+                                               ssl_client_hello_type_t type,
+                                               bool empty_session_id);
+
+// ssl_add_client_hello constructs a ClientHello and adds it to the outgoing
+// flight. It returns true on success and false on error.
+bool ssl_add_client_hello(SSL_HANDSHAKE *hs);
 
 enum ssl_cert_verify_context_t {
   ssl_cert_verify_server,
@@ -1935,6 +2177,9 @@ bool tls13_get_cert_verify_signature_input(
     SSL_HANDSHAKE *hs, Array<uint8_t> *out,
     enum ssl_cert_verify_context_t cert_verify_context);
 
+// ssl_is_valid_alpn_list returns whether |in| is a valid ALPN protocol list.
+bool ssl_is_valid_alpn_list(Span<const uint8_t> in);
+
 // ssl_is_alpn_protocol_allowed returns whether |protocol| is a valid server
 // selection for |hs->ssl|'s client preferences.
 bool ssl_is_alpn_protocol_allowed(const SSL_HANDSHAKE *hs,
@@ -1946,6 +2191,13 @@ bool ssl_is_alpn_protocol_allowed(const SSL_HANDSHAKE *hs,
 bool ssl_negotiate_alpn(SSL_HANDSHAKE *hs, uint8_t *out_alert,
                         const SSL_CLIENT_HELLO *client_hello);
 
+// ssl_get_local_application_settings looks up the configured ALPS value for
+// |protocol|. If found, it sets |*out_settings| to the value and returns true.
+// Otherwise, it returns false.
+bool ssl_get_local_application_settings(const SSL_HANDSHAKE *hs,
+                                        Span<const uint8_t> *out_settings,
+                                        Span<const uint8_t> protocol);
+
 // ssl_negotiate_alps negotiates the ALPS extension, if applicable. It returns
 // true on successful negotiation or if nothing was negotiated. It returns false
 // and sets |*out_alert| to an alert on error.
@@ -1982,6 +2234,10 @@ bool ssl_output_cert_chain(SSL_HANDSHAKE *hs);
 // handshake. Note, in TLS 1.2 resumptions, this session is immutable.
 const SSL_SESSION *ssl_handshake_session(const SSL_HANDSHAKE *hs);
 
+// ssl_done_writing_client_hello is called after the last ClientHello is written
+// by |hs|. It releases some memory that is no longer needed.
+void ssl_done_writing_client_hello(SSL_HANDSHAKE *hs);
+
 
 // SSLKEYLOGFILE functions.
 
@@ -1993,8 +2249,11 @@ bool ssl_log_secret(const SSL *ssl, const char *label,
 
 // ClientHello functions.
 
-bool ssl_client_hello_init(const SSL *ssl, SSL_CLIENT_HELLO *out,
-                           const SSLMessage &msg);
+// ssl_client_hello_init parses |body| as a ClientHello message, excluding the
+// message header, and writes the result to |*out|. It returns true on success
+// and false on error. This function is exported for testing.
+OPENSSL_EXPORT bool ssl_client_hello_init(const SSL *ssl, SSL_CLIENT_HELLO *out,
+                                          Span<const uint8_t> body);
 
 bool ssl_client_hello_get_extension(const SSL_CLIENT_HELLO *client_hello,
                                     CBS *out, uint16_t extension_type);
@@ -2009,7 +2268,8 @@ bool ssl_client_cipher_list_contains_cipher(
 // connection, the values for each index will be deterministic. This allows the
 // same ClientHello be sent twice for a HelloRetryRequest or the same group be
 // advertised in both supported_groups and key_shares.
-uint16_t ssl_get_grease_value(SSL_HANDSHAKE *hs, enum ssl_grease_index_t index);
+uint16_t ssl_get_grease_value(const SSL_HANDSHAKE *hs,
+                              enum ssl_grease_index_t index);
 
 
 // Signature algorithms.
@@ -2169,10 +2429,11 @@ struct SSL_PROTOCOL_METHOD {
   // init_message begins a new handshake message of type |type|. |cbb| is the
   // root CBB to be passed into |finish_message|. |*body| is set to a child CBB
   // the caller should write to. It returns true on success and false on error.
-  bool (*init_message)(SSL *ssl, CBB *cbb, CBB *body, uint8_t type);
+  bool (*init_message)(const SSL *ssl, CBB *cbb, CBB *body, uint8_t type);
   // finish_message finishes a handshake message. It sets |*out_msg| to the
   // serialized message. It returns true on success and false on error.
-  bool (*finish_message)(SSL *ssl, CBB *cbb, bssl::Array<uint8_t> *out_msg);
+  bool (*finish_message)(const SSL *ssl, CBB *cbb,
+                         bssl::Array<uint8_t> *out_msg);
   // add_message adds a handshake message to the pending flight. It returns
   // true on success and false on error.
   bool (*add_message)(SSL *ssl, bssl::Array<uint8_t> msg);
@@ -2321,6 +2582,16 @@ enum ssl_shutdown_t {
   ssl_shutdown_error = 2,
 };
 
+enum ssl_ech_status_t {
+  // ssl_ech_none indicates ECH was not offered, or we have not gotten far
+  // enough in the handshake to determine the status.
+  ssl_ech_none,
+  // ssl_ech_accepted indicates the server accepted ECH.
+  ssl_ech_accepted,
+  // ssl_ech_rejected indicates the server was offered ECH but rejected it.
+  ssl_ech_rejected,
+};
+
 struct SSL3_STATE {
   static constexpr bool kAllowUniquePtr = true;
 
@@ -2383,9 +2654,8 @@ struct SSL3_STATE {
   // key_update_count is the number of consecutive KeyUpdates received.
   uint8_t key_update_count = 0;
 
-  // The negotiated Token Binding key parameter. Only valid if
-  // |token_binding_negotiated| is set.
-  uint8_t negotiated_token_binding_param = 0;
+  // ech_status indicates whether ECH was accepted by the server.
+  ssl_ech_status_t ech_status = ssl_ech_none;
 
   // skip_early_data instructs the record layer to skip unexpected early data
   // messages when 0RTT is rejected.
@@ -2420,9 +2690,8 @@ struct SSL3_STATE {
 
   bool send_connection_binding : 1;
 
-  // In a client, this means that the server supported Channel ID and that a
-  // Channel ID was sent. In a server it means that we echoed support for
-  // Channel IDs and that |channel_id| will be valid after the handshake.
+  // channel_id_valid is true if, on the server, the client has negotiated a
+  // Channel ID and the |channel_id| field is filled in.
   bool channel_id_valid : 1;
 
   // key_update_pending is true if we have a KeyUpdate acknowledgment
@@ -2435,9 +2704,6 @@ struct SSL3_STATE {
   // early_data_accepted is true if early data was accepted by the server.
   bool early_data_accepted : 1;
 
-  // token_binding_negotiated is set if Token Binding was negotiated.
-  bool token_binding_negotiated : 1;
-
   // alert_dispatch is true there is an alert in |send_alert| to be sent.
   bool alert_dispatch : 1;
 
@@ -2720,7 +2986,8 @@ struct SSL_CONFIG {
 
   Array<uint16_t> supported_group_list;  // our list
 
-  // The client's Channel ID private key.
+  // channel_id_private is the client's Channel ID private key, or null if
+  // Channel ID should not be offered on this connection.
   UniquePtr<EVP_PKEY> channel_id_private;
 
   // For a client, this contains the list of supported protocols in wire
@@ -2731,9 +2998,6 @@ struct SSL_CONFIG {
   // along with their corresponding ALPS values.
   GrowableArray<ALPSConfig> alps_configs;
 
-  // Contains a list of supported Token Binding key parameters.
-  Array<uint8_t> token_binding_params;
-
   // Contains the QUIC transport params that this endpoint will send.
   Array<uint8_t> quic_transport_params;
 
@@ -2748,6 +3012,10 @@ struct SSL_CONFIG {
   // DTLS-SRTP.
   UniquePtr<STACK_OF(SRTP_PROTECTION_PROFILE)> srtp_profiles;
 
+  // client_ech_config_list, if not empty, is a serialized ECHConfigList
+  // structure for the client to use when negotiating ECH.
+  Array<uint8_t> client_ech_config_list;
+
   // verify_mode is a bitmask of |SSL_VERIFY_*| values.
   uint8_t verify_mode = SSL_VERIFY_NONE;
 
@@ -2762,9 +3030,8 @@ struct SSL_CONFIG {
   // whether OCSP stapling will be requested.
   bool ocsp_stapling_enabled : 1;
 
-  // channel_id_enabled is copied from the |SSL_CTX|. For a server, means that
-  // we'll accept Channel IDs from clients. For a client, means that we'll
-  // advertise support.
+  // channel_id_enabled is copied from the |SSL_CTX|. For a server, it means
+  // that we'll accept Channel IDs from clients. It is ignored on the client.
   bool channel_id_enabled : 1;
 
   // If enforce_rsa_key_usage is true, the handshake will fail if the
@@ -2794,6 +3061,9 @@ struct SSL_CONFIG {
   // QUIC drafts up to and including 32 used a different TLS extension
   // codepoint to convey QUIC's transport parameters.
   bool quic_use_legacy_codepoint : 1;
+
+  // permute_extensions is whether to permute extensions when sending messages.
+  bool permute_extensions : 1;
 };
 
 // From RFC 8446, used in determining PSK modes.
@@ -2814,7 +3084,7 @@ bool ssl_is_key_type_supported(int key_type);
 bool ssl_compare_public_and_private_key(const EVP_PKEY *pubkey,
                                        const EVP_PKEY *privkey);
 bool ssl_cert_check_private_key(const CERT *cert, const EVP_PKEY *privkey);
-int ssl_get_new_session(SSL_HANDSHAKE *hs, int is_server);
+bool ssl_get_new_session(SSL_HANDSHAKE *hs);
 int ssl_encrypt_ticket(SSL_HANDSHAKE *hs, CBB *out, const SSL_SESSION *session);
 int ssl_ctx_rotate_ticket_encryption_key(SSL_CTX *ctx);
 
@@ -2895,7 +3165,7 @@ void ssl_session_rebase_time(SSL *ssl, SSL_SESSION *session);
 void ssl_session_renew_timeout(SSL *ssl, SSL_SESSION *session,
                                uint32_t timeout);
 
-void ssl_update_cache(SSL_HANDSHAKE *hs, int mode);
+void ssl_update_cache(SSL *ssl);
 
 void ssl_send_alert(SSL *ssl, int level, int desc);
 int ssl_send_alert_impl(SSL *ssl, int level, int desc);
@@ -2917,14 +3187,14 @@ int tls_write_app_data(SSL *ssl, bool *out_needs_handshake, const uint8_t *buf,
 bool tls_new(SSL *ssl);
 void tls_free(SSL *ssl);
 
-bool tls_init_message(SSL *ssl, CBB *cbb, CBB *body, uint8_t type);
-bool tls_finish_message(SSL *ssl, CBB *cbb, Array<uint8_t> *out_msg);
+bool tls_init_message(const SSL *ssl, CBB *cbb, CBB *body, uint8_t type);
+bool tls_finish_message(const SSL *ssl, CBB *cbb, Array<uint8_t> *out_msg);
 bool tls_add_message(SSL *ssl, Array<uint8_t> msg);
 bool tls_add_change_cipher_spec(SSL *ssl);
 int tls_flush_flight(SSL *ssl);
 
-bool dtls1_init_message(SSL *ssl, CBB *cbb, CBB *body, uint8_t type);
-bool dtls1_finish_message(SSL *ssl, CBB *cbb, Array<uint8_t> *out_msg);
+bool dtls1_init_message(const SSL *ssl, CBB *cbb, CBB *body, uint8_t type);
+bool dtls1_finish_message(const SSL *ssl, CBB *cbb, Array<uint8_t> *out_msg);
 bool dtls1_add_message(SSL *ssl, Array<uint8_t> msg);
 bool dtls1_add_change_cipher_spec(SSL *ssl);
 int dtls1_flush_flight(SSL *ssl);
@@ -3009,11 +3279,27 @@ bool tls1_set_curves(Array<uint16_t> *out_group_ids, Span<const int> curves);
 // false.
 bool tls1_set_curves_list(Array<uint16_t> *out_group_ids, const char *curves);
 
-// ssl_add_clienthello_tlsext writes ClientHello extensions to |out|. It returns
-// true on success and false on failure. The |header_len| argument is the length
-// of the ClientHello written so far and is used to compute the padding length.
-// (It does not include the record header.)
-bool ssl_add_clienthello_tlsext(SSL_HANDSHAKE *hs, CBB *out, size_t header_len);
+// ssl_add_clienthello_tlsext writes ClientHello extensions to |out| for |type|.
+// It returns true on success and false on failure. The |header_len| argument is
+// the length of the ClientHello written so far and is used to compute the
+// padding length. (It does not include the record header or handshake headers.)
+//
+// If |type| is |ssl_client_hello_inner|, this function also writes the
+// compressed extensions to |out_encoded|. Otherwise, |out_encoded| should be
+// nullptr.
+//
+// On success, the function sets |*out_needs_psk_binder| to whether the last
+// ClientHello extension was the pre_shared_key extension and needs a PSK binder
+// filled in. The caller should then update |out| and, if applicable,
+// |out_encoded| with the binder after completing the whole message.
+//
+// If |omit_ech_len| is non-zero, the ECH extension is omitted, but padding is
+// computed as if there were an extension of length |omit_ech_len|. This is used
+// to compute ClientHelloOuterAAD.
+bool ssl_add_clienthello_tlsext(SSL_HANDSHAKE *hs, CBB *out, CBB *out_encoded,
+                                bool *out_needs_psk_binder,
+                                ssl_client_hello_type_t type, size_t header_len,
+                                size_t omit_ech_len);
 
 bool ssl_add_serverhello_tlsext(SSL_HANDSHAKE *hs, CBB *out);
 bool ssl_parse_clienthello_tlsext(SSL_HANDSHAKE *hs,
@@ -3056,12 +3342,6 @@ bool tls1_channel_id_hash(SSL_HANDSHAKE *hs, uint8_t *out, size_t *out_len);
 // data.
 bool tls1_record_handshake_hashes_for_channel_id(SSL_HANDSHAKE *hs);
 
-// ssl_do_channel_id_callback checks runs |hs->ssl->ctx->channel_id_cb| if
-// necessary. It returns true on success and false on fatal error. Note that, on
-// success, |hs->ssl->channel_id_private| may be unset, in which case the
-// operation should be retried later.
-bool ssl_do_channel_id_callback(SSL_HANDSHAKE *hs);
-
 // ssl_can_write returns whether |ssl| is allowed to write.
 bool ssl_can_write(const SSL *ssl);
 
@@ -3185,9 +3465,6 @@ struct ssl_ctx_st {
   int (*client_cert_cb)(SSL *ssl, X509 **out_x509,
                         EVP_PKEY **out_pkey) = nullptr;
 
-  // get channel id callback
-  void (*channel_id_cb)(SSL *ssl, EVP_PKEY **out_pkey) = nullptr;
-
   CRYPTO_EX_DATA ex_data;
 
   // Default values used when no per-SSL value is defined follow
@@ -3315,9 +3592,15 @@ struct ssl_ctx_st {
   // Supported group values inherited by SSL structure
   bssl::Array<uint16_t> supported_group_list;
 
-  // The client's Channel ID private key.
+  // channel_id_private is the client's Channel ID private key, or null if
+  // Channel ID should not be offered on this connection.
   bssl::UniquePtr<EVP_PKEY> channel_id_private;
 
+  // ech_keys contains the server's list of ECHConfig values and associated
+  // private keys. This list may be swapped out at any time, so all access must
+  // be synchronized through |lock|.
+  bssl::UniquePtr<SSL_ECH_KEYS> ech_keys;
+
   // keylog_callback, if not NULL, is the key logging callback. See
   // |SSL_CTX_set_keylog_callback|.
   void (*keylog_callback)(const SSL *ssl, const char *line) = nullptr;
@@ -3365,9 +3648,12 @@ struct ssl_ctx_st {
   // advertise support.
   bool channel_id_enabled : 1;
 
-  // grease_enabled is whether draft-davidben-tls-grease-01 is enabled.
+  // grease_enabled is whether GREASE (RFC 8701) is enabled.
   bool grease_enabled : 1;
 
+  // permute_extensions is whether to permute extensions when sending messages.
+  bool permute_extensions : 1;
+
   // allow_unknown_alpn_protos is whether the client allows unsolicited ALPN
   // protocols from the peer.
   bool allow_unknown_alpn_protos : 1;
@@ -3631,5 +3917,17 @@ struct ssl_session_st {
   friend void SSL_SESSION_free(SSL_SESSION *);
 };
 
+struct ssl_ech_keys_st {
+  ssl_ech_keys_st() = default;
+  ssl_ech_keys_st(const ssl_ech_keys_st &) = delete;
+  ssl_ech_keys_st &operator=(const ssl_ech_keys_st &) = delete;
+
+  bssl::GrowableArray<bssl::UniquePtr<bssl::ECHServerConfig>> configs;
+  CRYPTO_refcount_t references = 1;
+
+ private:
+  ~ssl_ech_keys_st() = default;
+  friend void SSL_ECH_KEYS_free(SSL_ECH_KEYS *);
+};
 
 #endif  // OPENSSL_HEADER_SSL_INTERNAL_H