use cfg_if::cfg_if; use std::io::{Read, Write}; use std::ops::{Deref, DerefMut}; use crate::dh::Dh; use crate::error::ErrorStack; #[cfg(any(ossl111, libressl340))] use crate::ssl::SslVersion; use crate::ssl::{ HandshakeError, Ssl, SslContext, SslContextBuilder, SslContextRef, SslMethod, SslMode, SslOptions, SslRef, SslStream, SslVerifyMode, }; use crate::version; use std::net::IpAddr; const FFDHE_2048: &str = " -----BEGIN DH PARAMETERS----- MIIBCAKCAQEA//////////+t+FRYortKmq/cViAnPTzx2LnFg84tNpWp4TZBFGQz +8yTnc4kmz75fS/jY2MMddj2gbICrsRhetPfHtXV/WVhJDP1H18GbtCFY2VVPe0a 87VXE15/V8k1mE8McODmi3fipona8+/och3xWKE2rec1MKzKT0g6eXq8CrGCsyT7 YdEIqUuyyOP7uWrat2DX9GgdT0Kj3jlN9K5W7edjcrsZCwenyO4KbXCeAvzhzffi 7MA0BM0oNC9hkXL+nOmFg/+OTxIy7vKBg8P+OxtMb61zO7X8vC7CIAXFjvGDfRaD ssbzSibBsu/6iGtCOGEoXJf//////////wIBAg== -----END DH PARAMETERS----- "; #[allow(clippy::inconsistent_digit_grouping, clippy::unusual_byte_groupings)] fn ctx(method: SslMethod) -> Result { let mut ctx = SslContextBuilder::new(method)?; cfg_if! { if #[cfg(not(boringssl))] { let mut opts = SslOptions::ALL | SslOptions::NO_COMPRESSION | SslOptions::NO_SSLV2 | SslOptions::NO_SSLV3 | SslOptions::SINGLE_DH_USE | SslOptions::SINGLE_ECDH_USE; opts &= !SslOptions::DONT_INSERT_EMPTY_FRAGMENTS; ctx.set_options(opts); } } let mut mode = SslMode::AUTO_RETRY | SslMode::ACCEPT_MOVING_WRITE_BUFFER | SslMode::ENABLE_PARTIAL_WRITE; // This is quite a useful optimization for saving memory, but historically // caused CVEs in OpenSSL pre-1.0.1h, according to // https://bugs.python.org/issue25672 if version::number() >= 0x1_00_01_08_0 { mode |= SslMode::RELEASE_BUFFERS; } ctx.set_mode(mode); Ok(ctx) } /// A type which wraps client-side streams in a TLS session. /// /// OpenSSL's default configuration is highly insecure. This connector manages the OpenSSL /// structures, configuring cipher suites, session options, hostname verification, and more. /// /// OpenSSL's built-in hostname verification is used when linking against OpenSSL 1.0.2 or 1.1.0, /// and a custom implementation is used when linking against OpenSSL 1.0.1. #[derive(Clone, Debug)] pub struct SslConnector(SslContext); impl SslConnector { /// Creates a new builder for TLS connections. /// /// The default configuration is subject to change, and is currently derived from Python. pub fn builder(method: SslMethod) -> Result { let mut ctx = ctx(method)?; ctx.set_default_verify_paths()?; ctx.set_cipher_list( "DEFAULT:!aNULL:!eNULL:!MD5:!3DES:!DES:!RC4:!IDEA:!SEED:!aDSS:!SRP:!PSK", )?; setup_verify(&mut ctx); Ok(SslConnectorBuilder(ctx)) } /// Initiates a client-side TLS session on a stream. /// /// The domain is used for SNI and hostname verification. pub fn connect(&self, domain: &str, stream: S) -> Result, HandshakeError> where S: Read + Write, { self.configure()?.connect(domain, stream) } /// Returns a structure allowing for configuration of a single TLS session before connection. pub fn configure(&self) -> Result { Ssl::new(&self.0).map(|ssl| ConnectConfiguration { ssl, sni: true, verify_hostname: true, }) } /// Consumes the `SslConnector`, returning the inner raw `SslContext`. pub fn into_context(self) -> SslContext { self.0 } /// Returns a shared reference to the inner raw `SslContext`. pub fn context(&self) -> &SslContextRef { &self.0 } } /// A builder for `SslConnector`s. pub struct SslConnectorBuilder(SslContextBuilder); impl SslConnectorBuilder { /// Consumes the builder, returning an `SslConnector`. pub fn build(self) -> SslConnector { SslConnector(self.0.build()) } } impl Deref for SslConnectorBuilder { type Target = SslContextBuilder; fn deref(&self) -> &SslContextBuilder { &self.0 } } impl DerefMut for SslConnectorBuilder { fn deref_mut(&mut self) -> &mut SslContextBuilder { &mut self.0 } } /// A type which allows for configuration of a client-side TLS session before connection. pub struct ConnectConfiguration { ssl: Ssl, sni: bool, verify_hostname: bool, } impl ConnectConfiguration { /// A builder-style version of `set_use_server_name_indication`. pub fn use_server_name_indication(mut self, use_sni: bool) -> ConnectConfiguration { self.set_use_server_name_indication(use_sni); self } /// Configures the use of Server Name Indication (SNI) when connecting. /// /// Defaults to `true`. pub fn set_use_server_name_indication(&mut self, use_sni: bool) { self.sni = use_sni; } /// A builder-style version of `set_verify_hostname`. pub fn verify_hostname(mut self, verify_hostname: bool) -> ConnectConfiguration { self.set_verify_hostname(verify_hostname); self } /// Configures the use of hostname verification when connecting. /// /// Defaults to `true`. /// /// # Warning /// /// You should think very carefully before you use this method. If hostname verification is not /// used, *any* valid certificate for *any* site will be trusted for use from any other. This /// introduces a significant vulnerability to man-in-the-middle attacks. pub fn set_verify_hostname(&mut self, verify_hostname: bool) { self.verify_hostname = verify_hostname; } /// Returns an `Ssl` configured to connect to the provided domain. /// /// The domain is used for SNI (if it is not an IP address) and hostname verification if enabled. pub fn into_ssl(mut self, domain: &str) -> Result { if self.sni && domain.parse::().is_err() { self.ssl.set_hostname(domain)?; } if self.verify_hostname { setup_verify_hostname(&mut self.ssl, domain)?; } Ok(self.ssl) } /// Initiates a client-side TLS session on a stream. /// /// The domain is used for SNI and hostname verification if enabled. pub fn connect(self, domain: &str, stream: S) -> Result, HandshakeError> where S: Read + Write, { self.into_ssl(domain)?.connect(stream) } } impl Deref for ConnectConfiguration { type Target = SslRef; fn deref(&self) -> &SslRef { &self.ssl } } impl DerefMut for ConnectConfiguration { fn deref_mut(&mut self) -> &mut SslRef { &mut self.ssl } } /// A type which wraps server-side streams in a TLS session. /// /// OpenSSL's default configuration is highly insecure. This connector manages the OpenSSL /// structures, configuring cipher suites, session options, and more. #[derive(Clone)] pub struct SslAcceptor(SslContext); impl SslAcceptor { /// Creates a new builder configured to connect to non-legacy clients. This should generally be /// considered a reasonable default choice. /// /// This corresponds to the intermediate configuration of version 5 of Mozilla's server side TLS /// recommendations. See its [documentation][docs] for more details on specifics. /// /// [docs]: https://wiki.mozilla.org/Security/Server_Side_TLS pub fn mozilla_intermediate_v5(method: SslMethod) -> Result { let mut ctx = ctx(method)?; ctx.set_options(SslOptions::NO_TLSV1 | SslOptions::NO_TLSV1_1); let dh = Dh::params_from_pem(FFDHE_2048.as_bytes())?; ctx.set_tmp_dh(&dh)?; setup_curves(&mut ctx)?; ctx.set_cipher_list( "ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-GCM-SHA384:\ ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:\ DHE-RSA-AES128-GCM-SHA256:DHE-RSA-AES256-GCM-SHA384" )?; #[cfg(any(ossl111, libressl340))] ctx.set_ciphersuites( "TLS_AES_128_GCM_SHA256:TLS_AES_256_GCM_SHA384:TLS_CHACHA20_POLY1305_SHA256", )?; Ok(SslAcceptorBuilder(ctx)) } /// Creates a new builder configured to connect to modern clients. /// /// This corresponds to the modern configuration of version 5 of Mozilla's server side TLS recommendations. /// See its [documentation][docs] for more details on specifics. /// /// Requires OpenSSL 1.1.1 or LibreSSL 3.4.0 or newer. /// /// [docs]: https://wiki.mozilla.org/Security/Server_Side_TLS #[cfg(any(ossl111, libressl340))] pub fn mozilla_modern_v5(method: SslMethod) -> Result { let mut ctx = ctx(method)?; ctx.set_min_proto_version(Some(SslVersion::TLS1_3))?; ctx.set_ciphersuites( "TLS_AES_128_GCM_SHA256:TLS_AES_256_GCM_SHA384:TLS_CHACHA20_POLY1305_SHA256", )?; Ok(SslAcceptorBuilder(ctx)) } /// Creates a new builder configured to connect to non-legacy clients. This should generally be /// considered a reasonable default choice. /// /// This corresponds to the intermediate configuration of version 4 of Mozilla's server side TLS /// recommendations. See its [documentation][docs] for more details on specifics. /// /// [docs]: https://wiki.mozilla.org/Security/Server_Side_TLS // FIXME remove in next major version pub fn mozilla_intermediate(method: SslMethod) -> Result { let mut ctx = ctx(method)?; ctx.set_options(SslOptions::CIPHER_SERVER_PREFERENCE); #[cfg(any(ossl111, libressl340))] ctx.set_options(SslOptions::NO_TLSV1_3); let dh = Dh::params_from_pem(FFDHE_2048.as_bytes())?; ctx.set_tmp_dh(&dh)?; setup_curves(&mut ctx)?; ctx.set_cipher_list( "ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:ECDHE-ECDSA-AES128-GCM-SHA256:\ ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:\ DHE-RSA-AES128-GCM-SHA256:DHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-AES128-SHA256:ECDHE-RSA-AES128-SHA256:\ ECDHE-ECDSA-AES128-SHA:ECDHE-RSA-AES256-SHA384:ECDHE-RSA-AES128-SHA:ECDHE-ECDSA-AES256-SHA384:\ ECDHE-ECDSA-AES256-SHA:ECDHE-RSA-AES256-SHA:DHE-RSA-AES128-SHA256:DHE-RSA-AES128-SHA:\ DHE-RSA-AES256-SHA256:DHE-RSA-AES256-SHA:ECDHE-ECDSA-DES-CBC3-SHA:ECDHE-RSA-DES-CBC3-SHA:\ EDH-RSA-DES-CBC3-SHA:AES128-GCM-SHA256:AES256-GCM-SHA384:AES128-SHA256:AES256-SHA256:AES128-SHA:\ AES256-SHA:DES-CBC3-SHA:!DSS", )?; Ok(SslAcceptorBuilder(ctx)) } /// Creates a new builder configured to connect to modern clients. /// /// This corresponds to the modern configuration of version 4 of Mozilla's server side TLS recommendations. /// See its [documentation][docs] for more details on specifics. /// /// [docs]: https://wiki.mozilla.org/Security/Server_Side_TLS // FIXME remove in next major version pub fn mozilla_modern(method: SslMethod) -> Result { let mut ctx = ctx(method)?; ctx.set_options( SslOptions::CIPHER_SERVER_PREFERENCE | SslOptions::NO_TLSV1 | SslOptions::NO_TLSV1_1, ); #[cfg(any(ossl111, libressl340))] ctx.set_options(SslOptions::NO_TLSV1_3); setup_curves(&mut ctx)?; ctx.set_cipher_list( "ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-CHACHA20-POLY1305:\ ECDHE-RSA-CHACHA20-POLY1305:ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:\ ECDHE-ECDSA-AES256-SHA384:ECDHE-RSA-AES256-SHA384:ECDHE-ECDSA-AES128-SHA256:ECDHE-RSA-AES128-SHA256", )?; Ok(SslAcceptorBuilder(ctx)) } /// Initiates a server-side TLS session on a stream. pub fn accept(&self, stream: S) -> Result, HandshakeError> where S: Read + Write, { let ssl = Ssl::new(&self.0)?; ssl.accept(stream) } /// Consumes the `SslAcceptor`, returning the inner raw `SslContext`. pub fn into_context(self) -> SslContext { self.0 } /// Returns a shared reference to the inner raw `SslContext`. pub fn context(&self) -> &SslContextRef { &self.0 } } /// A builder for `SslAcceptor`s. pub struct SslAcceptorBuilder(SslContextBuilder); impl SslAcceptorBuilder { /// Consumes the builder, returning a `SslAcceptor`. pub fn build(self) -> SslAcceptor { SslAcceptor(self.0.build()) } } impl Deref for SslAcceptorBuilder { type Target = SslContextBuilder; fn deref(&self) -> &SslContextBuilder { &self.0 } } impl DerefMut for SslAcceptorBuilder { fn deref_mut(&mut self) -> &mut SslContextBuilder { &mut self.0 } } cfg_if! { if #[cfg(ossl110)] { #[allow(clippy::unnecessary_wraps)] fn setup_curves(_: &mut SslContextBuilder) -> Result<(), ErrorStack> { Ok(()) } } else if #[cfg(any(ossl102, libressl))] { fn setup_curves(ctx: &mut SslContextBuilder) -> Result<(), ErrorStack> { ctx.set_ecdh_auto(true) } } else { fn setup_curves(ctx: &mut SslContextBuilder) -> Result<(), ErrorStack> { use crate::ec::EcKey; use crate::nid::Nid; let curve = EcKey::from_curve_name(Nid::X9_62_PRIME256V1)?; ctx.set_tmp_ecdh(&curve) } } } cfg_if! { if #[cfg(any(ossl102, libressl261))] { fn setup_verify(ctx: &mut SslContextBuilder) { ctx.set_verify(SslVerifyMode::PEER); } fn setup_verify_hostname(ssl: &mut SslRef, domain: &str) -> Result<(), ErrorStack> { use crate::x509::verify::X509CheckFlags; let param = ssl.param_mut(); param.set_hostflags(X509CheckFlags::NO_PARTIAL_WILDCARDS); match domain.parse() { Ok(ip) => param.set_ip(ip), Err(_) => param.set_host(domain), } } } else { fn setup_verify(ctx: &mut SslContextBuilder) { ctx.set_verify_callback(SslVerifyMode::PEER, verify::verify_callback); } fn setup_verify_hostname(ssl: &mut Ssl, domain: &str) -> Result<(), ErrorStack> { let domain = domain.to_string(); let hostname_idx = verify::try_get_hostname_idx()?; ssl.set_ex_data(*hostname_idx, domain); Ok(()) } mod verify { use std::net::IpAddr; use std::str; use once_cell::sync::OnceCell; use crate::error::ErrorStack; use crate::ex_data::Index; use crate::nid::Nid; use crate::ssl::Ssl; use crate::stack::Stack; use crate::x509::{ GeneralName, X509NameRef, X509Ref, X509StoreContext, X509StoreContextRef, X509VerifyResult, }; static HOSTNAME_IDX: OnceCell> = OnceCell::new(); pub fn try_get_hostname_idx() -> Result<&'static Index, ErrorStack> { HOSTNAME_IDX.get_or_try_init(Ssl::new_ex_index) } pub fn verify_callback(preverify_ok: bool, x509_ctx: &mut X509StoreContextRef) -> bool { if !preverify_ok || x509_ctx.error_depth() != 0 { return preverify_ok; } let hostname_idx = try_get_hostname_idx().expect("failed to initialize hostname index"); let ok = match ( x509_ctx.current_cert(), X509StoreContext::ssl_idx() .ok() .and_then(|idx| x509_ctx.ex_data(idx)) .and_then(|ssl| ssl.ex_data(*hostname_idx)), ) { (Some(x509), Some(domain)) => verify_hostname(domain, &x509), _ => true, }; if !ok { x509_ctx.set_error(X509VerifyResult::APPLICATION_VERIFICATION); } ok } fn verify_hostname(domain: &str, cert: &X509Ref) -> bool { match cert.subject_alt_names() { Some(names) => verify_subject_alt_names(domain, names), None => verify_subject_name(domain, &cert.subject_name()), } } fn verify_subject_alt_names(domain: &str, names: Stack) -> bool { let ip = domain.parse(); for name in &names { match ip { Ok(ip) => { if let Some(actual) = name.ipaddress() { if matches_ip(&ip, actual) { return true; } } } Err(_) => { if let Some(pattern) = name.dnsname() { if matches_dns(pattern, domain) { return true; } } } } } false } fn verify_subject_name(domain: &str, subject_name: &X509NameRef) -> bool { match subject_name.entries_by_nid(Nid::COMMONNAME).next() { Some(pattern) => { let pattern = match str::from_utf8(pattern.data().as_slice()) { Ok(pattern) => pattern, Err(_) => return false, }; // Unlike SANs, IP addresses in the subject name don't have a // different encoding. match domain.parse::() { Ok(ip) => pattern .parse::() .ok() .map_or(false, |pattern| pattern == ip), Err(_) => matches_dns(pattern, domain), } } None => false, } } fn matches_dns(mut pattern: &str, mut hostname: &str) -> bool { // first strip trailing . off of pattern and hostname to normalize if pattern.ends_with('.') { pattern = &pattern[..pattern.len() - 1]; } if hostname.ends_with('.') { hostname = &hostname[..hostname.len() - 1]; } matches_wildcard(pattern, hostname).unwrap_or_else(|| pattern.eq_ignore_ascii_case(hostname)) } fn matches_wildcard(pattern: &str, hostname: &str) -> Option { let wildcard_location = match pattern.find('*') { Some(l) => l, None => return None, }; let mut dot_idxs = pattern.match_indices('.').map(|(l, _)| l); let wildcard_end = match dot_idxs.next() { Some(l) => l, None => return None, }; // Never match wildcards if the pattern has less than 2 '.'s (no *.com) // // This is a bit dubious, as it doesn't disallow other TLDs like *.co.uk. // Chrome has a black- and white-list for this, but Firefox (via NSS) does // the same thing we do here. // // The Public Suffix (https://www.publicsuffix.org/) list could // potentially be used here, but it's both huge and updated frequently // enough that management would be a PITA. if dot_idxs.next().is_none() { return None; } // Wildcards can only be in the first component, and must be the entire first label if wildcard_location != 0 || wildcard_end != wildcard_location + 1 { return None; } let hostname_label_end = match hostname.find('.') { Some(l) => l, None => return None, }; let pattern_after_wildcard = &pattern[wildcard_end..]; let hostname_after_wildcard = &hostname[hostname_label_end..]; Some(pattern_after_wildcard.eq_ignore_ascii_case(hostname_after_wildcard)) } fn matches_ip(expected: &IpAddr, actual: &[u8]) -> bool { match *expected { IpAddr::V4(ref addr) => actual == addr.octets(), IpAddr::V6(ref addr) => actual == addr.octets(), } } #[test] fn test_dns_match() { use crate::ssl::connector::verify::matches_dns; assert!(matches_dns("website.tld", "website.tld")); // A name should match itself. assert!(matches_dns("website.tld", "wEbSiTe.tLd")); // DNS name matching ignores case of hostname. assert!(matches_dns("wEbSiTe.TlD", "website.tld")); // DNS name matching ignores case of subject. assert!(matches_dns("xn--bcher-kva.tld", "xn--bcher-kva.tld")); // Likewise, nothing special to punycode names. assert!(matches_dns("xn--bcher-kva.tld", "xn--BcHer-Kva.tLd")); // And punycode must be compared similarly case-insensitively. assert!(matches_dns("*.example.com", "subdomain.example.com")); // Wildcard matching works. assert!(matches_dns("*.eXaMpLe.cOm", "subdomain.example.com")); // Wildcard matching ignores case of subject. assert!(matches_dns("*.example.com", "sUbDoMaIn.eXaMpLe.cOm")); // Wildcard matching ignores case of hostname. assert!(!matches_dns("prefix*.example.com", "p.example.com")); // Prefix longer than the label works and does not match. assert!(!matches_dns("*suffix.example.com", "s.example.com")); // Suffix longer than the label works and does not match. assert!(!matches_dns("prefix*.example.com", "prefix.example.com")); // Partial wildcards do not work. assert!(!matches_dns("*suffix.example.com", "suffix.example.com")); // Partial wildcards do not work. assert!(!matches_dns("prefix*.example.com", "prefixdomain.example.com")); // Partial wildcards do not work. assert!(!matches_dns("*suffix.example.com", "domainsuffix.example.com")); // Partial wildcards do not work. assert!(!matches_dns("xn--*.example.com", "subdomain.example.com")); // Punycode domains with wildcard parts do not match. assert!(!matches_dns("xN--*.example.com", "subdomain.example.com")); // And we can't bypass a punycode test with weird casing. assert!(!matches_dns("Xn--*.example.com", "subdomain.example.com")); // And we can't bypass a punycode test with weird casing. assert!(!matches_dns("XN--*.example.com", "subdomain.example.com")); // And we can't bypass a punycode test with weird casing. } } } }