rustls/server/
handy.rs

1use alloc::sync::Arc;
2use alloc::vec::Vec;
3use core::fmt::Debug;
4
5use crate::server::ClientHello;
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::sync::Arc;
30    use alloc::vec::Vec;
31    use core::fmt::{Debug, Formatter};
32
33    use crate::lock::Mutex;
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/// Something which always resolves to the same cert chain.
170#[derive(Debug)]
171pub(super) struct AlwaysResolvesChain(Arc<sign::CertifiedKey>);
172
173impl AlwaysResolvesChain {
174    /// Creates an `AlwaysResolvesChain`, using the supplied `CertifiedKey`.
175    pub(super) fn new(certified_key: sign::CertifiedKey) -> Self {
176        Self(Arc::new(certified_key))
177    }
178
179    /// Creates an `AlwaysResolvesChain`, using the supplied `CertifiedKey` and OCSP response.
180    ///
181    /// If non-empty, the given OCSP response is attached.
182    pub(super) fn new_with_extras(certified_key: sign::CertifiedKey, ocsp: Vec<u8>) -> Self {
183        let mut r = Self::new(certified_key);
184
185        {
186            let cert = Arc::make_mut(&mut r.0);
187            if !ocsp.is_empty() {
188                cert.ocsp = Some(ocsp);
189            }
190        }
191
192        r
193    }
194}
195
196impl server::ResolvesServerCert for AlwaysResolvesChain {
197    fn resolve(&self, _client_hello: ClientHello<'_>) -> Option<Arc<sign::CertifiedKey>> {
198        Some(Arc::clone(&self.0))
199    }
200}
201
202#[cfg(any(feature = "std", feature = "hashbrown"))]
203mod sni_resolver {
204    use alloc::string::{String, ToString};
205    use alloc::sync::Arc;
206    use core::fmt::Debug;
207
208    use pki_types::{DnsName, ServerName};
209
210    use crate::error::Error;
211    use crate::hash_map::HashMap;
212    use crate::server::ClientHello;
213    use crate::webpki::{verify_server_name, ParsedCertificate};
214    use crate::{server, sign};
215
216    /// Something that resolves do different cert chains/keys based
217    /// on client-supplied server name (via SNI).
218    #[derive(Debug)]
219    pub struct ResolvesServerCertUsingSni {
220        by_name: HashMap<String, Arc<sign::CertifiedKey>>,
221    }
222
223    impl ResolvesServerCertUsingSni {
224        /// Create a new and empty (i.e., knows no certificates) resolver.
225        pub fn new() -> Self {
226            Self {
227                by_name: HashMap::new(),
228            }
229        }
230
231        /// Add a new `sign::CertifiedKey` to be used for the given SNI `name`.
232        ///
233        /// This function fails if `name` is not a valid DNS name, or if
234        /// it's not valid for the supplied certificate, or if the certificate
235        /// chain is syntactically faulty.
236        pub fn add(&mut self, name: &str, ck: sign::CertifiedKey) -> Result<(), Error> {
237            let server_name = {
238                let checked_name = DnsName::try_from(name)
239                    .map_err(|_| Error::General("Bad DNS name".into()))
240                    .map(|name| name.to_lowercase_owned())?;
241                ServerName::DnsName(checked_name)
242            };
243
244            // Check the certificate chain for validity:
245            // - it should be non-empty list
246            // - the first certificate should be parsable as a x509v3,
247            // - the first certificate should quote the given server name
248            //   (if provided)
249            //
250            // These checks are not security-sensitive.  They are the
251            // *server* attempting to detect accidental misconfiguration.
252
253            ck.end_entity_cert()
254                .and_then(ParsedCertificate::try_from)
255                .and_then(|cert| verify_server_name(&cert, &server_name))?;
256
257            if let ServerName::DnsName(name) = server_name {
258                self.by_name
259                    .insert(name.as_ref().to_string(), Arc::new(ck));
260            }
261            Ok(())
262        }
263    }
264
265    impl server::ResolvesServerCert for ResolvesServerCertUsingSni {
266        fn resolve(&self, client_hello: ClientHello<'_>) -> Option<Arc<sign::CertifiedKey>> {
267            if let Some(name) = client_hello.server_name() {
268                self.by_name.get(name).cloned()
269            } else {
270                // This kind of resolver requires SNI
271                None
272            }
273        }
274    }
275
276    #[cfg(test)]
277    mod tests {
278        use super::*;
279        use crate::server::ResolvesServerCert;
280
281        #[test]
282        fn test_resolvesservercertusingsni_requires_sni() {
283            let rscsni = ResolvesServerCertUsingSni::new();
284            assert!(rscsni
285                .resolve(ClientHello::new(&None, &[], None, &[]))
286                .is_none());
287        }
288
289        #[test]
290        fn test_resolvesservercertusingsni_handles_unknown_name() {
291            let rscsni = ResolvesServerCertUsingSni::new();
292            let name = DnsName::try_from("hello.com")
293                .unwrap()
294                .to_owned();
295            assert!(rscsni
296                .resolve(ClientHello::new(&Some(name), &[], None, &[]))
297                .is_none());
298        }
299    }
300}
301
302#[cfg(any(feature = "std", feature = "hashbrown"))]
303pub use sni_resolver::ResolvesServerCertUsingSni;
304
305#[cfg(test)]
306mod tests {
307    use std::vec;
308
309    use super::*;
310    use crate::server::{ProducesTickets, StoresServerSessions};
311
312    #[test]
313    fn test_noserversessionstorage_drops_put() {
314        let c = NoServerSessionStorage {};
315        assert!(!c.put(vec![0x01], vec![0x02]));
316    }
317
318    #[test]
319    fn test_noserversessionstorage_denies_gets() {
320        let c = NoServerSessionStorage {};
321        c.put(vec![0x01], vec![0x02]);
322        assert_eq!(c.get(&[]), None);
323        assert_eq!(c.get(&[0x01]), None);
324        assert_eq!(c.get(&[0x02]), None);
325    }
326
327    #[test]
328    fn test_noserversessionstorage_denies_takes() {
329        let c = NoServerSessionStorage {};
330        assert_eq!(c.take(&[]), None);
331        assert_eq!(c.take(&[0x01]), None);
332        assert_eq!(c.take(&[0x02]), None);
333    }
334
335    #[test]
336    fn test_neverproducestickets_does_nothing() {
337        let npt = NeverProducesTickets {};
338        assert!(!npt.enabled());
339        assert_eq!(0, npt.lifetime());
340        assert_eq!(None, npt.encrypt(&[]));
341        assert_eq!(None, npt.decrypt(&[]));
342    }
343}
rustls/server/handy.rs

rustls/server/
handy.rs
