rustls/server/
handy.rs

1use alloc::vec::Vec;
2use core::fmt::Debug;
3
4use crate::server::ClientHello;
5use crate::sync::Arc;
6use crate::{server, sign};
7
8/// Something which never stores sessions.
9#[derive(Debug)]
10pub struct NoServerSessionStorage {}
11
12impl server::StoresServerSessions for NoServerSessionStorage {
13    fn put(&self, _id: Vec<u8>, _sec: Vec<u8>) -> bool {
14        false
15    }
16    fn get(&self, _id: &[u8]) -> Option<Vec<u8>> {
17        None
18    }
19    fn take(&self, _id: &[u8]) -> Option<Vec<u8>> {
20        None
21    }
22    fn can_cache(&self) -> bool {
23        false
24    }
25}
26
27#[cfg(any(feature = "std", feature = "hashbrown"))]
28mod cache {
29    use alloc::vec::Vec;
30    use core::fmt::{Debug, Formatter};
31
32    use crate::lock::Mutex;
33    use crate::sync::Arc;
34    use crate::{limited_cache, server};
35
36    /// An implementer of `StoresServerSessions` that stores everything
37    /// in memory.  If enforces a limit on the number of stored sessions
38    /// to bound memory usage.
39    pub struct ServerSessionMemoryCache {
40        cache: Mutex<limited_cache::LimitedCache<Vec<u8>, Vec<u8>>>,
41    }
42
43    impl ServerSessionMemoryCache {
44        /// Make a new ServerSessionMemoryCache.  `size` is the maximum
45        /// number of stored sessions, and may be rounded-up for
46        /// efficiency.
47        #[cfg(feature = "std")]
48        pub fn new(size: usize) -> Arc<Self> {
49            Arc::new(Self {
50                cache: Mutex::new(limited_cache::LimitedCache::new(size)),
51            })
52        }
53
54        /// Make a new ServerSessionMemoryCache.  `size` is the maximum
55        /// number of stored sessions, and may be rounded-up for
56        /// efficiency.
57        #[cfg(not(feature = "std"))]
58        pub fn new<M: crate::lock::MakeMutex>(size: usize) -> Arc<Self> {
59            Arc::new(Self {
60                cache: Mutex::new::<M>(limited_cache::LimitedCache::new(size)),
61            })
62        }
63    }
64
65    impl server::StoresServerSessions for ServerSessionMemoryCache {
66        fn put(&self, key: Vec<u8>, value: Vec<u8>) -> bool {
67            self.cache
68                .lock()
69                .unwrap()
70                .insert(key, value);
71            true
72        }
73
74        fn get(&self, key: &[u8]) -> Option<Vec<u8>> {
75            self.cache
76                .lock()
77                .unwrap()
78                .get(key)
79                .cloned()
80        }
81
82        fn take(&self, key: &[u8]) -> Option<Vec<u8>> {
83            self.cache.lock().unwrap().remove(key)
84        }
85
86        fn can_cache(&self) -> bool {
87            true
88        }
89    }
90
91    impl Debug for ServerSessionMemoryCache {
92        fn fmt(&self, f: &mut Formatter<'_>) -> core::fmt::Result {
93            f.debug_struct("ServerSessionMemoryCache")
94                .finish()
95        }
96    }
97
98    #[cfg(test)]
99    mod tests {
100        use std::vec;
101
102        use super::*;
103        use crate::server::StoresServerSessions;
104
105        #[test]
106        fn test_serversessionmemorycache_accepts_put() {
107            let c = ServerSessionMemoryCache::new(4);
108            assert!(c.put(vec![0x01], vec![0x02]));
109        }
110
111        #[test]
112        fn test_serversessionmemorycache_persists_put() {
113            let c = ServerSessionMemoryCache::new(4);
114            assert!(c.put(vec![0x01], vec![0x02]));
115            assert_eq!(c.get(&[0x01]), Some(vec![0x02]));
116            assert_eq!(c.get(&[0x01]), Some(vec![0x02]));
117        }
118
119        #[test]
120        fn test_serversessionmemorycache_overwrites_put() {
121            let c = ServerSessionMemoryCache::new(4);
122            assert!(c.put(vec![0x01], vec![0x02]));
123            assert!(c.put(vec![0x01], vec![0x04]));
124            assert_eq!(c.get(&[0x01]), Some(vec![0x04]));
125        }
126
127        #[test]
128        fn test_serversessionmemorycache_drops_to_maintain_size_invariant() {
129            let c = ServerSessionMemoryCache::new(2);
130            assert!(c.put(vec![0x01], vec![0x02]));
131            assert!(c.put(vec![0x03], vec![0x04]));
132            assert!(c.put(vec![0x05], vec![0x06]));
133            assert!(c.put(vec![0x07], vec![0x08]));
134            assert!(c.put(vec![0x09], vec![0x0a]));
135
136            let count = c.get(&[0x01]).iter().count()
137                + c.get(&[0x03]).iter().count()
138                + c.get(&[0x05]).iter().count()
139                + c.get(&[0x07]).iter().count()
140                + c.get(&[0x09]).iter().count();
141
142            assert!(count < 5);
143        }
144    }
145}
146
147#[cfg(any(feature = "std", feature = "hashbrown"))]
148pub use cache::ServerSessionMemoryCache;
149
150/// Something which never produces tickets.
151#[derive(Debug)]
152pub(super) struct NeverProducesTickets {}
153
154impl server::ProducesTickets for NeverProducesTickets {
155    fn enabled(&self) -> bool {
156        false
157    }
158    fn lifetime(&self) -> u32 {
159        0
160    }
161    fn encrypt(&self, _bytes: &[u8]) -> Option<Vec<u8>> {
162        None
163    }
164    fn decrypt(&self, _bytes: &[u8]) -> Option<Vec<u8>> {
165        None
166    }
167}
168
169/// An exemplar `ResolvesServerCert` implementation that always resolves to a single
170/// [RFC 7250] raw public key.
171///
172/// [RFC 7250]: https://tools.ietf.org/html/rfc7250
173#[derive(Clone, Debug)]
174pub struct AlwaysResolvesServerRawPublicKeys(Arc<sign::CertifiedKey>);
175
176impl AlwaysResolvesServerRawPublicKeys {
177    /// Create a new `AlwaysResolvesServerRawPublicKeys` instance.
178    pub fn new(certified_key: Arc<sign::CertifiedKey>) -> Self {
179        Self(certified_key)
180    }
181}
182
183impl server::ResolvesServerCert for AlwaysResolvesServerRawPublicKeys {
184    fn resolve(&self, _client_hello: ClientHello<'_>) -> Option<Arc<sign::CertifiedKey>> {
185        Some(Arc::clone(&self.0))
186    }
187
188    fn only_raw_public_keys(&self) -> bool {
189        true
190    }
191}
192
193#[cfg(any(feature = "std", feature = "hashbrown"))]
194mod sni_resolver {
195    use alloc::string::{String, ToString};
196    use core::fmt::Debug;
197
198    use pki_types::{DnsName, ServerName};
199
200    use crate::error::Error;
201    use crate::hash_map::HashMap;
202    use crate::server::ClientHello;
203    use crate::sync::Arc;
204    use crate::webpki::{ParsedCertificate, verify_server_name};
205    use crate::{server, sign};
206
207    /// Something that resolves do different cert chains/keys based
208    /// on client-supplied server name (via SNI).
209    #[derive(Debug)]
210    pub struct ResolvesServerCertUsingSni {
211        by_name: HashMap<String, Arc<sign::CertifiedKey>>,
212    }
213
214    impl ResolvesServerCertUsingSni {
215        /// Create a new and empty (i.e., knows no certificates) resolver.
216        pub fn new() -> Self {
217            Self {
218                by_name: HashMap::new(),
219            }
220        }
221
222        /// Add a new `sign::CertifiedKey` to be used for the given SNI `name`.
223        ///
224        /// This function fails if `name` is not a valid DNS name, or if
225        /// it's not valid for the supplied certificate, or if the certificate
226        /// chain is syntactically faulty.
227        pub fn add(&mut self, name: &str, ck: sign::CertifiedKey) -> Result<(), Error> {
228            let server_name = {
229                let checked_name = DnsName::try_from(name)
230                    .map_err(|_| Error::General("Bad DNS name".into()))
231                    .map(|name| name.to_lowercase_owned())?;
232                ServerName::DnsName(checked_name)
233            };
234
235            // Check the certificate chain for validity:
236            // - it should be non-empty list
237            // - the first certificate should be parsable as a x509v3,
238            // - the first certificate should quote the given server name
239            //   (if provided)
240            //
241            // These checks are not security-sensitive.  They are the
242            // *server* attempting to detect accidental misconfiguration.
243
244            ck.end_entity_cert()
245                .and_then(ParsedCertificate::try_from)
246                .and_then(|cert| verify_server_name(&cert, &server_name))?;
247
248            if let ServerName::DnsName(name) = server_name {
249                self.by_name
250                    .insert(name.as_ref().to_string(), Arc::new(ck));
251            }
252            Ok(())
253        }
254    }
255
256    impl server::ResolvesServerCert for ResolvesServerCertUsingSni {
257        fn resolve(&self, client_hello: ClientHello<'_>) -> Option<Arc<sign::CertifiedKey>> {
258            if let Some(name) = client_hello.server_name() {
259                self.by_name.get(name).cloned()
260            } else {
261                // This kind of resolver requires SNI
262                None
263            }
264        }
265    }
266
267    #[cfg(test)]
268    mod tests {
269        use super::*;
270        use crate::server::ResolvesServerCert;
271
272        #[test]
273        fn test_resolvesservercertusingsni_requires_sni() {
274            let rscsni = ResolvesServerCertUsingSni::new();
275            assert!(
276                rscsni
277                    .resolve(ClientHello {
278                        server_name: &None,
279                        signature_schemes: &[],
280                        alpn: None,
281                        server_cert_types: None,
282                        client_cert_types: None,
283                        cipher_suites: &[],
284                        certificate_authorities: None,
285                    })
286                    .is_none()
287            );
288        }
289
290        #[test]
291        fn test_resolvesservercertusingsni_handles_unknown_name() {
292            let rscsni = ResolvesServerCertUsingSni::new();
293            let name = DnsName::try_from("hello.com")
294                .unwrap()
295                .to_owned();
296            assert!(
297                rscsni
298                    .resolve(ClientHello {
299                        server_name: &Some(name),
300                        signature_schemes: &[],
301                        alpn: None,
302                        server_cert_types: None,
303                        client_cert_types: None,
304                        cipher_suites: &[],
305                        certificate_authorities: None,
306                    })
307                    .is_none()
308            );
309        }
310    }
311}
312
313#[cfg(any(feature = "std", feature = "hashbrown"))]
314pub use sni_resolver::ResolvesServerCertUsingSni;
315
316#[cfg(test)]
317mod tests {
318    use std::vec;
319
320    use super::*;
321    use crate::server::{ProducesTickets, StoresServerSessions};
322
323    #[test]
324    fn test_noserversessionstorage_drops_put() {
325        let c = NoServerSessionStorage {};
326        assert!(!c.put(vec![0x01], vec![0x02]));
327    }
328
329    #[test]
330    fn test_noserversessionstorage_denies_gets() {
331        let c = NoServerSessionStorage {};
332        c.put(vec![0x01], vec![0x02]);
333        assert_eq!(c.get(&[]), None);
334        assert_eq!(c.get(&[0x01]), None);
335        assert_eq!(c.get(&[0x02]), None);
336    }
337
338    #[test]
339    fn test_noserversessionstorage_denies_takes() {
340        let c = NoServerSessionStorage {};
341        assert_eq!(c.take(&[]), None);
342        assert_eq!(c.take(&[0x01]), None);
343        assert_eq!(c.take(&[0x02]), None);
344    }
345
346    #[test]
347    fn test_neverproducestickets_does_nothing() {
348        let npt = NeverProducesTickets {};
349        assert!(!npt.enabled());
350        assert_eq!(0, npt.lifetime());
351        assert_eq!(None, npt.encrypt(&[]));
352        assert_eq!(None, npt.decrypt(&[]));
353    }
354}
rustls/server/handy.rs

rustls/server/
handy.rs
