rust/bssl-tls/src/alerts.rs - boringssl - Git at Google

 // Copyright 2026 The BoringSSL Authors
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
 //     https://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.

 //! TLS Alerts

 use core::{
     ffi::{CStr, c_int},
     fmt,
 };

 use bssl_macros::bssl_enum;

 bssl_enum! {
     #[derive(Debug, Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
     #[non_exhaustive]
     /// TLS alert description
     ///
     /// These alert variants have [IANA entries].
     ///
     /// [IANA entries]: <https://www.iana.org/assignments/tls-parameters/tls-parameters.xhtml#tls-parameters-6>
     pub enum AlertDescription : u8 {
         /// `close_notify`
         ///
         /// This alert notifies the recipient that the sender will not send any more messages on
         /// this connection.
         /// Any data received after a closure alert has been received MUST be ignored.
         CloseNotify = bssl_sys::SSL_AD_CLOSE_NOTIFY as u8,
         /// `unexpected_message`
         ///
         /// This alert signals a fatal error.
         /// The connection must be terminated.
         UnexpectedMessage = bssl_sys::SSL_AD_UNEXPECTED_MESSAGE as u8,
         /// `bad_record_mac`
         ///
         /// This alert signals a fatal decryption error.
         /// The connection must be terminated.
         BadRecordMac = bssl_sys::SSL_AD_BAD_RECORD_MAC as u8,
         /// `decryption_failed`, reserved and used up until TLS 1.3.
         DecryptionFailed = bssl_sys::SSL_AD_DECRYPTION_FAILED as u8,
         /// `record_overflow`
         ///
         /// This alert signals that a record of length more than 2^14 bytes
         /// was received.
         /// The connection must be terminated.
         RecordOverflow = bssl_sys::SSL_AD_RECORD_OVERFLOW as u8,
         /// `decompression_failure`, reserved and used up until TLS 1.3.
         DecompressionFailure = bssl_sys::SSL_AD_DECOMPRESSION_FAILURE as u8,
         /// `handshake_failure`
         ///
         /// This alert signals a fatal handshake error due to failure to negotiate a supported
         /// set of parameters.
         /// The handshake must be aborted.
         HandshakeFailure = bssl_sys::SSL_AD_HANDSHAKE_FAILURE as u8,
         /// `no_certificate`, reserved and used up until TLS 1.3.
         NoCertificate = bssl_sys::SSL_AD_NO_CERTIFICATE as u8,
         /// `bad_certificate`
         ///
         /// This alert signals a certificate verification error.
         /// The reason could be the use of insecure parameters such as `SHA-1` or `MD5` hash
         /// algorithms, or the signature verification failed.
         /// The handshake must be aborted.
         BadCertificate = bssl_sys::SSL_AD_BAD_CERTIFICATE as u8,
         /// `unsupported_certificate`
         ///
         /// This alert signals an unsupported certificate was transmitted.
         /// The connection must be terminated.
         UnsupportedCertificate = bssl_sys::SSL_AD_UNSUPPORTED_CERTIFICATE as u8,
         /// `certificate_revoked`
         ///
         /// This alert signals a certificate was revoked.
         /// The connection must be terminated.
         CertificateRevoked = bssl_sys::SSL_AD_CERTIFICATE_REVOKED as u8,
         /// `certificate_expired`
         ///
         /// This alert signals a certificate has expired.
         /// The connection must be terminated.
         CertificateExpired = bssl_sys::SSL_AD_CERTIFICATE_EXPIRED as u8,
         /// `certificate_unknown`
         ///
         /// This alert signals some other unspecified issue arose in processing the certificate,
         /// rendering it unacceptable.
         /// The connection must be terminated.
         CertificateUnknown = bssl_sys::SSL_AD_CERTIFICATE_UNKNOWN as u8,
         /// `illegal_parameter`
         ///
         /// A field in the handshake was incorrect or inconsistent with other fields.
         /// This alert is used for errors which conform to the formal protocol syntax,
         /// but are otherwise incorrect.
         /// The connection must be terminated.
         IllegalParameter = bssl_sys::SSL_AD_ILLEGAL_PARAMETER as u8,
         /// `unknown_ca`
         ///
         /// A valid certificate chain or partial chain was received,
         /// but the certificate was not accepted because the CA certificate could not be located
         /// or could not be matched with a known trust anchor.
         /// The connection must be terminated.
         UnknownCa = bssl_sys::SSL_AD_UNKNOWN_CA as u8,
         /// `access_denied`
         ///
         /// A valid certificate or PSK was received, but when access control was applied,
         /// the sender decided not to proceed with negotiation.
         /// The connection must be terminated.
         AccessDenied = bssl_sys::SSL_AD_ACCESS_DENIED as u8,
         /// `decode_error`
         ///
         /// A message could not be decoded because some field was out of the specified range or
         /// the length of the message was incorrect.
         /// This alert is used for errors where the message does not conform to the formal
         /// protocol syntax.
         /// This alert should never be observed in communication between proper implementations,
         /// except when messages were corrupted in the network.
         /// The connection must be terminated.
         DecodeError = bssl_sys::SSL_AD_DECODE_ERROR as u8,
         /// `decrypt_error`
         ///
         /// A handshake cryptographic operation, which is not on the record layer, has failed,
         /// including inability to correctly verify a signature, validate a `Finished` message
         /// or a PSK binder.
         /// The connection must be terminated.
         DecryptError = bssl_sys::SSL_AD_DECRYPT_ERROR as u8,
         /// `export_restriction`, reserved and used up until TLS 1.3.
         ///
         /// The connection must be terminated.
         ExportRestriction = bssl_sys::SSL_AD_EXPORT_RESTRICTION as u8,
         /// `protocol_version`
         ///
         /// The protocol version the peer has attempted to negotiate is recognized
         /// but not supported.
         /// The connection must be terminated.
         ProtocolVersion = bssl_sys::SSL_AD_PROTOCOL_VERSION as u8,
         /// `insufficient_security`
         ///
         /// Returned instead of "handshake_failure" when a negotiation has failed specifically
         /// because the server requires parameters more secure than those supported by the client.
         /// The connection must be terminated.
         InsufficientSecurity = bssl_sys::SSL_AD_INSUFFICIENT_SECURITY as u8,
         /// `internal_error`
         ///
         /// An internal error unrelated to the peer or the correctness of the protocol,
         /// such as a memory allocation failure, makes it impossible to continue.
         /// The connection must be terminated.
         InternalError = bssl_sys::SSL_AD_INTERNAL_ERROR as u8,
         /// `inappropriate_fallback`
         ///
         /// Sent by a server in response to an invalid connection retry attempt from a client.
         /// The connection must be terminated.
         InappropriateFallback = bssl_sys::SSL_AD_INAPPROPRIATE_FALLBACK as u8,
         /// `user_cancelled`
         ///
         /// This alert notifies the recipient that the sender is canceling the handshake
         /// for some reason unrelated to a protocol failure.
         UserCancelled = bssl_sys::SSL_AD_USER_CANCELLED as u8,
         /// `no_renegotiation`, reserved and used up until TLS 1.3.
         NoRenegotiation = bssl_sys::SSL_AD_NO_RENEGOTIATION as u8,
         /// `missing_extension`
         ///
         /// Sent by endpoints that receive a handshake message not containing an extension that
         /// is mandatory to send for the offered TLS version or other negotiated parameters.
         /// The connection must be terminated.
         MissingExtension = bssl_sys::SSL_AD_MISSING_EXTENSION as u8,
         /// `unsupported_extension`
         ///
         /// Sent by endpoints receiving any handshake message containing an extension in a
         /// `ServerHello`, `HelloRetryRequest`, `EncryptedExtensions`, or `Certificate` not first
         /// offered in the corresponding `ClientHello` or `CertificateRequest`.
         UnsupportedExtension = bssl_sys::SSL_AD_UNSUPPORTED_EXTENSION as u8,
         /// `certificate_unobtainable`, reserved and used up until TLS 1.3.
         CertificateUnobtainable = bssl_sys::SSL_AD_CERTIFICATE_UNOBTAINABLE as u8,
         /// `unrecognized_name`
         ///
         /// Sent by servers when no server exists identified by the name provided by the client via
         /// the `server_name` extension.
         UnrecognizedName = bssl_sys::SSL_AD_UNRECOGNIZED_NAME as u8,
         /// `bad_certificate_status_response`
         ///
         /// Sent by clients when an invalid or unacceptable OCSP response is provided by the server
         /// via the `status_request` extension.
         BadCertificateStatusResponse = bssl_sys::SSL_AD_BAD_CERTIFICATE_STATUS_RESPONSE as u8,
         /// `bad_certificate_hash_value`, reserved and used up until TLS 1.3.
         BadCertificateHashValue = bssl_sys::SSL_AD_BAD_CERTIFICATE_HASH_VALUE as u8,
         /// `unknown_psk_identity`
         ///
         /// Sent by servers when PSK key establishment is desired but no acceptable PSK identity is
         /// provided by the client.
         /// Sending this alert is optional.
         /// Servers may instead choose to send a `decrypt_error` alert to merely indicate an invalid
         /// PSK identity.
         UnknownPskIdentity = bssl_sys::SSL_AD_UNKNOWN_PSK_IDENTITY as u8,
         /// `certificate_required`
         ///
         /// Sent by servers when a client certificate is desired but none was provided by
         /// the client.
         CertificateRequired = bssl_sys::SSL_AD_CERTIFICATE_REQUIRED as u8,
         /// `no_application_protocol`
         ///
         /// Sent by servers when a client `application_layer_protocol_negotiation` extension
         /// advertises only protocols that the server does not support.
         NoApplicationProtocol = bssl_sys::SSL_AD_NO_APPLICATION_PROTOCOL as u8,
         /// `ech_required`
         ///
         /// The client must send this alert when it offered an `encrypted_client_hello` extension
         /// but was not accepted by the server.
         EchRequired = bssl_sys::SSL_AD_ECH_REQUIRED as u8,
     }
 }

 impl AlertDescription {
     /// Extract long description of the alert.
     pub fn get_description(self) -> &'static str {
         let cstr = unsafe {
             // Safety: we are only accessing static NUL-terminated string data that is plain ASCII.
             CStr::from_ptr(bssl_sys::SSL_alert_desc_string_long(self as c_int))
         };
         cstr.to_str()
             .expect("BoringSSL description string unexpectedly contains non-UTF-8 bytes")
     }
 }

 impl fmt::Display for AlertDescription {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         write!(f, "{}", self.get_description())
     }
 }
	// Copyright 2026 The BoringSSL Authors
	//
	// Licensed under the Apache License, Version 2.0 (the "License");
	// you may not use this file except in compliance with the License.
	// You may obtain a copy of the License at
	//
	// https://www.apache.org/licenses/LICENSE-2.0
	//
	// Unless required by applicable law or agreed to in writing, software
	// distributed under the License is distributed on an "AS IS" BASIS,
	// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	// See the License for the specific language governing permissions and
	// limitations under the License.

	//! TLS Alerts

	use core::{
	ffi::{CStr, c_int},
	fmt,
	};

	use bssl_macros::bssl_enum;

	bssl_enum! {
	#[derive(Debug, Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
	#[non_exhaustive]
	/// TLS alert description
	///
	/// These alert variants have [IANA entries].
	///
	/// [IANA entries]: <https://www.iana.org/assignments/tls-parameters/tls-parameters.xhtml#tls-parameters-6>
	pub enum AlertDescription : u8 {
	/// `close_notify`
	///
	/// This alert notifies the recipient that the sender will not send any more messages on
	/// this connection.
	/// Any data received after a closure alert has been received MUST be ignored.
	CloseNotify = bssl_sys::SSL_AD_CLOSE_NOTIFY as u8,
	/// `unexpected_message`
	///
	/// This alert signals a fatal error.
	/// The connection must be terminated.
	UnexpectedMessage = bssl_sys::SSL_AD_UNEXPECTED_MESSAGE as u8,
	/// `bad_record_mac`
	///
	/// This alert signals a fatal decryption error.
	/// The connection must be terminated.
	BadRecordMac = bssl_sys::SSL_AD_BAD_RECORD_MAC as u8,
	/// `decryption_failed`, reserved and used up until TLS 1.3.
	DecryptionFailed = bssl_sys::SSL_AD_DECRYPTION_FAILED as u8,
	/// `record_overflow`
	///
	/// This alert signals that a record of length more than 2^14 bytes
	/// was received.
	/// The connection must be terminated.
	RecordOverflow = bssl_sys::SSL_AD_RECORD_OVERFLOW as u8,
	/// `decompression_failure`, reserved and used up until TLS 1.3.
	DecompressionFailure = bssl_sys::SSL_AD_DECOMPRESSION_FAILURE as u8,
	/// `handshake_failure`
	///
	/// This alert signals a fatal handshake error due to failure to negotiate a supported
	/// set of parameters.
	/// The handshake must be aborted.
	HandshakeFailure = bssl_sys::SSL_AD_HANDSHAKE_FAILURE as u8,
	/// `no_certificate`, reserved and used up until TLS 1.3.
	NoCertificate = bssl_sys::SSL_AD_NO_CERTIFICATE as u8,
	/// `bad_certificate`
	///
	/// This alert signals a certificate verification error.
	/// The reason could be the use of insecure parameters such as `SHA-1` or `MD5` hash
	/// algorithms, or the signature verification failed.
	/// The handshake must be aborted.
	BadCertificate = bssl_sys::SSL_AD_BAD_CERTIFICATE as u8,
	/// `unsupported_certificate`
	///
	/// This alert signals an unsupported certificate was transmitted.
	/// The connection must be terminated.
	UnsupportedCertificate = bssl_sys::SSL_AD_UNSUPPORTED_CERTIFICATE as u8,
	/// `certificate_revoked`
	///
	/// This alert signals a certificate was revoked.
	/// The connection must be terminated.
	CertificateRevoked = bssl_sys::SSL_AD_CERTIFICATE_REVOKED as u8,
	/// `certificate_expired`
	///
	/// This alert signals a certificate has expired.
	/// The connection must be terminated.
	CertificateExpired = bssl_sys::SSL_AD_CERTIFICATE_EXPIRED as u8,
	/// `certificate_unknown`
	///
	/// This alert signals some other unspecified issue arose in processing the certificate,
	/// rendering it unacceptable.
	/// The connection must be terminated.
	CertificateUnknown = bssl_sys::SSL_AD_CERTIFICATE_UNKNOWN as u8,
	/// `illegal_parameter`
	///
	/// A field in the handshake was incorrect or inconsistent with other fields.
	/// This alert is used for errors which conform to the formal protocol syntax,
	/// but are otherwise incorrect.
	/// The connection must be terminated.
	IllegalParameter = bssl_sys::SSL_AD_ILLEGAL_PARAMETER as u8,
	/// `unknown_ca`
	///
	/// A valid certificate chain or partial chain was received,
	/// but the certificate was not accepted because the CA certificate could not be located
	/// or could not be matched with a known trust anchor.
	/// The connection must be terminated.
	UnknownCa = bssl_sys::SSL_AD_UNKNOWN_CA as u8,
	/// `access_denied`
	///
	/// A valid certificate or PSK was received, but when access control was applied,
	/// the sender decided not to proceed with negotiation.
	/// The connection must be terminated.
	AccessDenied = bssl_sys::SSL_AD_ACCESS_DENIED as u8,
	/// `decode_error`
	///
	/// A message could not be decoded because some field was out of the specified range or
	/// the length of the message was incorrect.
	/// This alert is used for errors where the message does not conform to the formal
	/// protocol syntax.
	/// This alert should never be observed in communication between proper implementations,
	/// except when messages were corrupted in the network.
	/// The connection must be terminated.
	DecodeError = bssl_sys::SSL_AD_DECODE_ERROR as u8,
	/// `decrypt_error`
	///
	/// A handshake cryptographic operation, which is not on the record layer, has failed,
	/// including inability to correctly verify a signature, validate a `Finished` message
	/// or a PSK binder.
	/// The connection must be terminated.
	DecryptError = bssl_sys::SSL_AD_DECRYPT_ERROR as u8,
	/// `export_restriction`, reserved and used up until TLS 1.3.
	///
	/// The connection must be terminated.
	ExportRestriction = bssl_sys::SSL_AD_EXPORT_RESTRICTION as u8,
	/// `protocol_version`
	///
	/// The protocol version the peer has attempted to negotiate is recognized
	/// but not supported.
	/// The connection must be terminated.
	ProtocolVersion = bssl_sys::SSL_AD_PROTOCOL_VERSION as u8,
	/// `insufficient_security`
	///
	/// Returned instead of "handshake_failure" when a negotiation has failed specifically
	/// because the server requires parameters more secure than those supported by the client.
	/// The connection must be terminated.
	InsufficientSecurity = bssl_sys::SSL_AD_INSUFFICIENT_SECURITY as u8,
	/// `internal_error`
	///
	/// An internal error unrelated to the peer or the correctness of the protocol,
	/// such as a memory allocation failure, makes it impossible to continue.
	/// The connection must be terminated.
	InternalError = bssl_sys::SSL_AD_INTERNAL_ERROR as u8,
	/// `inappropriate_fallback`
	///
	/// Sent by a server in response to an invalid connection retry attempt from a client.
	/// The connection must be terminated.
	InappropriateFallback = bssl_sys::SSL_AD_INAPPROPRIATE_FALLBACK as u8,
	/// `user_cancelled`
	///
	/// This alert notifies the recipient that the sender is canceling the handshake
	/// for some reason unrelated to a protocol failure.
	UserCancelled = bssl_sys::SSL_AD_USER_CANCELLED as u8,
	/// `no_renegotiation`, reserved and used up until TLS 1.3.
	NoRenegotiation = bssl_sys::SSL_AD_NO_RENEGOTIATION as u8,
	/// `missing_extension`
	///
	/// Sent by endpoints that receive a handshake message not containing an extension that
	/// is mandatory to send for the offered TLS version or other negotiated parameters.
	/// The connection must be terminated.
	MissingExtension = bssl_sys::SSL_AD_MISSING_EXTENSION as u8,
	/// `unsupported_extension`
	///
	/// Sent by endpoints receiving any handshake message containing an extension in a
	/// `ServerHello`, `HelloRetryRequest`, `EncryptedExtensions`, or `Certificate` not first
	/// offered in the corresponding `ClientHello` or `CertificateRequest`.
	UnsupportedExtension = bssl_sys::SSL_AD_UNSUPPORTED_EXTENSION as u8,
	/// `certificate_unobtainable`, reserved and used up until TLS 1.3.
	CertificateUnobtainable = bssl_sys::SSL_AD_CERTIFICATE_UNOBTAINABLE as u8,
	/// `unrecognized_name`
	///
	/// Sent by servers when no server exists identified by the name provided by the client via
	/// the `server_name` extension.
	UnrecognizedName = bssl_sys::SSL_AD_UNRECOGNIZED_NAME as u8,
	/// `bad_certificate_status_response`
	///
	/// Sent by clients when an invalid or unacceptable OCSP response is provided by the server
	/// via the `status_request` extension.
	BadCertificateStatusResponse = bssl_sys::SSL_AD_BAD_CERTIFICATE_STATUS_RESPONSE as u8,
	/// `bad_certificate_hash_value`, reserved and used up until TLS 1.3.
	BadCertificateHashValue = bssl_sys::SSL_AD_BAD_CERTIFICATE_HASH_VALUE as u8,
	/// `unknown_psk_identity`
	///
	/// Sent by servers when PSK key establishment is desired but no acceptable PSK identity is
	/// provided by the client.
	/// Sending this alert is optional.
	/// Servers may instead choose to send a `decrypt_error` alert to merely indicate an invalid
	/// PSK identity.
	UnknownPskIdentity = bssl_sys::SSL_AD_UNKNOWN_PSK_IDENTITY as u8,
	/// `certificate_required`
	///
	/// Sent by servers when a client certificate is desired but none was provided by
	/// the client.
	CertificateRequired = bssl_sys::SSL_AD_CERTIFICATE_REQUIRED as u8,
	/// `no_application_protocol`
	///
	/// Sent by servers when a client `application_layer_protocol_negotiation` extension
	/// advertises only protocols that the server does not support.
	NoApplicationProtocol = bssl_sys::SSL_AD_NO_APPLICATION_PROTOCOL as u8,
	/// `ech_required`
	///
	/// The client must send this alert when it offered an `encrypted_client_hello` extension
	/// but was not accepted by the server.
	EchRequired = bssl_sys::SSL_AD_ECH_REQUIRED as u8,
	}
	}

	impl AlertDescription {
	/// Extract long description of the alert.
	pub fn get_description(self) -> &'static str {
	let cstr = unsafe {
	// Safety: we are only accessing static NUL-terminated string data that is plain ASCII.
	CStr::from_ptr(bssl_sys::SSL_alert_desc_string_long(self as c_int))
	};
	cstr.to_str()
	.expect("BoringSSL description string unexpectedly contains non-UTF-8 bytes")
	}
	}

	impl fmt::Display for AlertDescription {
	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
	write!(f, "{}", self.get_description())
	}
	}