. /include/boost/corosio /tls_context.hpp
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1   // 1   //
2   // Copyright (c) 2025 Vinnie Falco (vinnie.falco@gmail.com) 2   // Copyright (c) 2025 Vinnie Falco (vinnie.falco@gmail.com)
3   // Copyright (c) 2026 Michael Vandeberg 3   // Copyright (c) 2026 Michael Vandeberg
4   // 4   //
5   // Distributed under the Boost Software License, Version 1.0. (See accompanying 5   // Distributed under the Boost Software License, Version 1.0. (See accompanying
6   // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) 6   // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
7   // 7   //
8   // Official repository: https://github.com/cppalliance/corosio 8   // Official repository: https://github.com/cppalliance/corosio
9   // 9   //
10   10  
11   #ifndef BOOST_COROSIO_TLS_CONTEXT_HPP 11   #ifndef BOOST_COROSIO_TLS_CONTEXT_HPP
12   #define BOOST_COROSIO_TLS_CONTEXT_HPP 12   #define BOOST_COROSIO_TLS_CONTEXT_HPP
13   13  
14   #include <boost/corosio/detail/config.hpp> 14   #include <boost/corosio/detail/config.hpp>
15   15  
16   #include <cstddef> 16   #include <cstddef>
17   #include <functional> 17   #include <functional>
18   #include <span> 18   #include <span>
19   #include <system_error> 19   #include <system_error>
20   #include <memory> 20   #include <memory>
21   #include <string_view> 21   #include <string_view>
22   22  
23   namespace boost::corosio { 23   namespace boost::corosio {
24   24  
25   // 25   //
26   // Enumerations 26   // Enumerations
27   // 27   //
28   28  
29   /** TLS protocol version. 29   /** TLS protocol version.
30   30  
31   Specifies the minimum or maximum TLS protocol version to use 31   Specifies the minimum or maximum TLS protocol version to use
32   for connections. Only modern, secure versions are supported. 32   for connections. Only modern, secure versions are supported.
33   33  
34   @see tls_context::set_min_protocol_version 34   @see tls_context::set_min_protocol_version
35   @see tls_context::set_max_protocol_version 35   @see tls_context::set_max_protocol_version
36   */ 36   */
37   enum class tls_version 37   enum class tls_version
38   { 38   {
39   /// TLS 1.2 (RFC 5246). 39   /// TLS 1.2 (RFC 5246).
40   tls_1_2, 40   tls_1_2,
41   41  
42   /// TLS 1.3 (RFC 8446). 42   /// TLS 1.3 (RFC 8446).
43   tls_1_3 43   tls_1_3
44   }; 44   };
45   45  
46   /** Certificate and key file format. 46   /** Certificate and key file format.
47   47  
48   Specifies the encoding format for certificate and key data. 48   Specifies the encoding format for certificate and key data.
49   49  
50   @see tls_context::use_certificate 50   @see tls_context::use_certificate
51   @see tls_context::use_private_key 51   @see tls_context::use_private_key
52   */ 52   */
53   enum class tls_file_format 53   enum class tls_file_format
54   { 54   {
55   /// PEM format (Base64-encoded with header/footer lines). 55   /// PEM format (Base64-encoded with header/footer lines).
56   pem, 56   pem,
57   57  
58   /// DER format (raw ASN.1 binary encoding). 58   /// DER format (raw ASN.1 binary encoding).
59   der 59   der
60   }; 60   };
61   61  
62   /** Peer certificate verification mode. 62   /** Peer certificate verification mode.
63   63  
64   Controls how the TLS implementation verifies the peer's 64   Controls how the TLS implementation verifies the peer's
65   certificate during the handshake. 65   certificate during the handshake.
66   66  
67   @see tls_context::set_verify_mode 67   @see tls_context::set_verify_mode
68   */ 68   */
69   enum class tls_verify_mode 69   enum class tls_verify_mode
70   { 70   {
71   /// Do not request or verify the peer certificate. 71   /// Do not request or verify the peer certificate.
72   none, 72   none,
73   73  
74   /// Request and verify the peer certificate if presented. 74   /// Request and verify the peer certificate if presented.
75   peer, 75   peer,
76   76  
77   /// Require and verify the peer certificate (fail if not presented). 77   /// Require and verify the peer certificate (fail if not presented).
78   require_peer 78   require_peer
79   }; 79   };
80   80  
81   /** Certificate revocation checking policy. 81   /** Certificate revocation checking policy.
82   82  
83   Controls how certificate revocation status is checked during 83   Controls how certificate revocation status is checked during
84   verification. 84   verification.
85   85  
86   @see tls_context::set_revocation_policy 86   @see tls_context::set_revocation_policy
87   */ 87   */
88   enum class tls_revocation_policy 88   enum class tls_revocation_policy
89   { 89   {
90   /// Do not check revocation status. 90   /// Do not check revocation status.
91   disabled, 91   disabled,
92   92  
93   /// Check revocation but allow connection if status is unknown. 93   /// Check revocation but allow connection if status is unknown.
94   soft_fail, 94   soft_fail,
95   95  
96   /// Require successful revocation check (fail if status is unknown). 96   /// Require successful revocation check (fail if status is unknown).
97   hard_fail 97   hard_fail
98   }; 98   };
99   99  
100   /** Purpose for password callback invocation. 100   /** Purpose for password callback invocation.
101   101  
102   Indicates whether the password is needed for reading (decrypting) 102   Indicates whether the password is needed for reading (decrypting)
103   or writing (encrypting) key material. 103   or writing (encrypting) key material.
104   104  
105   @see tls_context::set_password_callback 105   @see tls_context::set_password_callback
106   */ 106   */
107   enum class tls_password_purpose 107   enum class tls_password_purpose
108   { 108   {
109   /// Password needed to decrypt/read protected key material. 109   /// Password needed to decrypt/read protected key material.
110   for_reading, 110   for_reading,
111   111  
112   /// Password needed to encrypt/write protected key material. 112   /// Password needed to encrypt/write protected key material.
113   for_writing 113   for_writing
114   }; 114   };
115   115  
116   class tls_context; 116   class tls_context;
117   117  
118   /** Exposes the certificate and error state to a verification callback. 118   /** Exposes the certificate and error state to a verification callback.
119   119  
120   An instance is passed to the callback installed via 120   An instance is passed to the callback installed via
121   tls_context::set_verify_callback during the TLS handshake. It 121   tls_context::set_verify_callback during the TLS handshake. It
122   exposes the backend's native verification handle so the callback 122   exposes the backend's native verification handle so the callback
123   can inspect the certificate and chain currently being verified. 123   can inspect the certificate and chain currently being verified.
124   124  
125   The value returned by native_handle() is, for the OpenSSL and 125   The value returned by native_handle() is, for the OpenSSL and
126   WolfSSL backends, an `X509_STORE_CTX*`. For portable inspection that 126   WolfSSL backends, an `X509_STORE_CTX*`. For portable inspection that
127   works across backends (for example certificate pinning), prefer 127   works across backends (for example certificate pinning), prefer
128   certificate(), which returns the DER encoding of the certificate 128   certificate(), which returns the DER encoding of the certificate
129   currently being verified. 129   currently being verified.
130   130  
131   @par Lifetime 131   @par Lifetime
132   132  
133   The wrapped handle and the certificate() bytes are owned by the TLS 133   The wrapped handle and the certificate() bytes are owned by the TLS
134   backend and are valid only for the duration of a single callback 134   backend and are valid only for the duration of a single callback
135   invocation. Do not retain them beyond the call. 135   invocation. Do not retain them beyond the call.
136   136  
137   @see tls_context::set_verify_callback 137   @see tls_context::set_verify_callback
138   */ 138   */
139   class verify_context 139   class verify_context
140   { 140   {
141   void* handle_; 141   void* handle_;
142   unsigned char const* der_; 142   unsigned char const* der_;
143   std::size_t der_len_; 143   std::size_t der_len_;
144   144  
145   public: 145   public:
146   /** Construct from a native handle and the current certificate. 146   /** Construct from a native handle and the current certificate.
147   147  
148   @param handle The backend verification handle (for OpenSSL and 148   @param handle The backend verification handle (for OpenSSL and
149   WolfSSL, an `X509_STORE_CTX*`). 149   WolfSSL, an `X509_STORE_CTX*`).
150   @param der Pointer to the DER encoding of the certificate under 150   @param der Pointer to the DER encoding of the certificate under
151   verification, or `nullptr` if unavailable. 151   verification, or `nullptr` if unavailable.
152   @param der_len Length of the DER encoding in bytes. 152   @param der_len Length of the DER encoding in bytes.
153   */ 153   */
154   verify_context( 154   verify_context(
155   void* handle, unsigned char const* der, std::size_t der_len) noexcept 155   void* handle, unsigned char const* der, std::size_t der_len) noexcept
156   : handle_(handle) 156   : handle_(handle)
157   , der_(der) 157   , der_(der)
158   , der_len_(der_len) 158   , der_len_(der_len)
159   { 159   {
160   } 160   }
161   161  
162   /** Return the native verification handle. 162   /** Return the native verification handle.
163   163  
164   Cast the result to the backend's verification context type 164   Cast the result to the backend's verification context type
165   (e.g. `X509_STORE_CTX*`) to inspect the certificate chain using 165   (e.g. `X509_STORE_CTX*`) to inspect the certificate chain using
166   backend-specific APIs. 166   backend-specific APIs.
167   167  
168   @return The native handle, or `nullptr` if none is available. 168   @return The native handle, or `nullptr` if none is available.
169   */ 169   */
170   void* native_handle() const noexcept 170   void* native_handle() const noexcept
171   { 171   {
172   return handle_; 172   return handle_;
173   } 173   }
174   174  
175   /** Return the DER encoding of the certificate being verified. 175   /** Return the DER encoding of the certificate being verified.
176   176  
177   This is the portable way to inspect the peer certificate from a 177   This is the portable way to inspect the peer certificate from a
178   verification callback. It works identically on every backend, 178   verification callback. It works identically on every backend,
179   without depending on backend-specific build options. A DER 179   without depending on backend-specific build options. A DER
180   certificate is an ASN.1 `SEQUENCE`, so the first byte is `0x30`. 180   certificate is an ASN.1 `SEQUENCE`, so the first byte is `0x30`.
181   181  
182   @return A view of the certificate's DER bytes, valid only for the 182   @return A view of the certificate's DER bytes, valid only for the
183   duration of the callback. Empty if the certificate is not 183   duration of the callback. Empty if the certificate is not
184   available. 184   available.
185   */ 185   */
MISUBC 186   ✗ std::span<unsigned char const> certificate() const noexcept 186   ✗ std::span<unsigned char const> certificate() const noexcept
187   { 187   {
MISUBC 188   ✗ return {der_, der_len_}; 188   ✗ return {der_, der_len_};
189   } 189   }
190   }; 190   };
191   191  
192   namespace detail { 192   namespace detail {
193   struct tls_context_data; 193   struct tls_context_data;
194   tls_context_data const& get_tls_context_data(tls_context const&) noexcept; 194   tls_context_data const& get_tls_context_data(tls_context const&) noexcept;
195   } // namespace detail 195   } // namespace detail
196   196  
197   #ifdef _MSC_VER 197   #ifdef _MSC_VER
198   #pragma warning(push) 198   #pragma warning(push)
199   #pragma warning(disable : 4251) // shared_ptr needs dll-interface 199   #pragma warning(disable : 4251) // shared_ptr needs dll-interface
200   #endif 200   #endif
201   201  
202   /** Configures the certificates, keys, and protocol settings a TLS stream uses. 202   /** Configures the certificates, keys, and protocol settings a TLS stream uses.
203   203  
204   The `tls_context` class provides a backend-agnostic interface for 204   The `tls_context` class provides a backend-agnostic interface for
205   configuring TLS connections. It stores credentials (certificates and 205   configuring TLS connections. It stores credentials (certificates and
206   private keys), trust anchors, protocol settings, and verification 206   private keys), trust anchors, protocol settings, and verification
207   options that are used when establishing TLS connections. 207   options that are used when establishing TLS connections.
208   208  
209   This class is a shared handle to an opaque implementation. Copies 209   This class is a shared handle to an opaque implementation. Copies
210   share the same underlying state. This allows contexts to be passed 210   share the same underlying state. This allows contexts to be passed
211   by value and shared across multiple TLS streams. 211   by value and shared across multiple TLS streams.
212   212  
213   This class abstracts the configuration phase of TLS across multiple 213   This class abstracts the configuration phase of TLS across multiple
214   backend implementations, among them OpenSSL, WolfSSL, mbedTLS and 214   backend implementations, among them OpenSSL, WolfSSL, mbedTLS and
215   Schannel. Portable code therefore works regardless of which TLS 215   Schannel. Portable code therefore works regardless of which TLS
216   library is linked. 216   library is linked.
217   217  
218   @par Modification After Stream Creation 218   @par Modification After Stream Creation
219   219  
220   Modifying a context after creating a TLS stream from it 220   Modifying a context after creating a TLS stream from it
221   results in undefined behavior. The context's configuration is 221   results in undefined behavior. The context's configuration is
222   captured when the first stream is constructed, and subsequent 222   captured when the first stream is constructed, and subsequent
223   modifications are not reflected in existing or new streams 223   modifications are not reflected in existing or new streams
224   sharing the context. 224   sharing the context.
225   225  
226   If different configurations are needed, create separate context 226   If different configurations are needed, create separate context
227   objects. 227   objects.
228   228  
229   @par Thread Safety 229   @par Thread Safety
230   230  
231   Distinct objects: Safe. 231   Distinct objects: Safe.
232   232  
233   Shared objects: Unsafe. A context must not be modified while 233   Shared objects: Unsafe. A context must not be modified while
234   any thread is creating streams from it. 234   any thread is creating streams from it.
235   235  
236   @par Example 236   @par Example
237   @par !example tls_context 237   @par !example tls_context
238   238  
239   @see tls_role 239   @see tls_role
240   */ 240   */
241   class BOOST_COROSIO_DECL tls_context 241   class BOOST_COROSIO_DECL tls_context
242   { 242   {
243   struct implementation; 243   struct implementation;
244   std::shared_ptr<implementation> impl_; 244   std::shared_ptr<implementation> impl_;
245   245  
246   friend detail::tls_context_data const& 246   friend detail::tls_context_data const&
247   detail::get_tls_context_data(tls_context const&) noexcept; 247   detail::get_tls_context_data(tls_context const&) noexcept;
248   248  
249   public: 249   public:
250   /** Construct a default TLS context. 250   /** Construct a default TLS context.
251   251  
252   Creates a context with default settings suitable for TLS 1.2 252   Creates a context with default settings suitable for TLS 1.2
253   and TLS 1.3 connections. No certificates or trust anchors are 253   and TLS 1.3 connections. No certificates or trust anchors are
254   loaded; call the appropriate methods to configure credentials 254   loaded; call the appropriate methods to configure credentials
255   and verification. 255   and verification.
256   256  
257   @par Example 257   @par Example
258   @par !example tls_context 258   @par !example tls_context
259   */ 259   */
260   tls_context(); 260   tls_context();
261   261  
262   /** Creates a new handle that shares ownership of the underlying 262   /** Creates a new handle that shares ownership of the underlying
263   TLS context state with `other`. 263   TLS context state with `other`.
264   264  
265   @param other The context to copy from. 265   @param other The context to copy from.
266   */ 266   */
HITCBC 267   2 tls_context(tls_context const& other) = default; 267   2 tls_context(tls_context const& other) = default;
268   268  
269   /** Releases the current context's shared ownership and acquires 269   /** Releases the current context's shared ownership and acquires
270   shared ownership of `other`'s underlying state. 270   shared ownership of `other`'s underlying state.
271   271  
272   @param other The context to copy from. 272   @param other The context to copy from.
273   273  
274   @return Reference to this context. 274   @return Reference to this context.
275   */ 275   */
HITCBC 276   1 tls_context& operator=(tls_context const& other) = default; 276   1 tls_context& operator=(tls_context const& other) = default;
277   277  
278   /** Transfers ownership of the TLS context from another instance. 278   /** Transfers ownership of the TLS context from another instance.
279   After the move, `other` is in a valid but empty state. 279   After the move, `other` is in a valid but empty state.
280   280  
281   @param other The context to move from. 281   @param other The context to move from.
282   */ 282   */
HITCBC 283   2 tls_context(tls_context&& other) noexcept = default; 283   2 tls_context(tls_context&& other) noexcept = default;
284   284  
285   /** Releases the current context's shared ownership and transfers 285   /** Releases the current context's shared ownership and transfers
286   ownership from another instance. After the move, `other` is 286   ownership from another instance. After the move, `other` is
287   in a valid but empty state. 287   in a valid but empty state.
288   288  
289   @param other The context to move from. 289   @param other The context to move from.
290   290  
291   @return Reference to this context. 291   @return Reference to this context.
292   */ 292   */
HITCBC 293   1 tls_context& operator=(tls_context&& other) noexcept = default; 293   1 tls_context& operator=(tls_context&& other) noexcept = default;
294   294  
295   /** Releases this handle's shared ownership of the underlying 295   /** Releases this handle's shared ownership of the underlying
296   context. The context state is destroyed when the last handle 296   context. The context state is destroyed when the last handle
297   is released. 297   is released.
298   */ 298   */
HITCBC 299   55 ~tls_context() = default; 299   55 ~tls_context() = default;
300   300  
301   // 301   //
302   // Credential Loading 302   // Credential Loading
303   // 303   //
304   304  
305   /** Load the entity certificate from a memory buffer. 305   /** Load the entity certificate from a memory buffer.
306   306  
307   Sets the certificate that identifies this endpoint to the peer. 307   Sets the certificate that identifies this endpoint to the peer.
308   For servers, this is the server certificate. For clients using 308   For servers, this is the server certificate. For clients using
309   mutual TLS, this is the client certificate. 309   mutual TLS, this is the client certificate.
310   310  
311   The certificate must match the private key loaded via 311   The certificate must match the private key loaded via
312   `use_private_key()` or `use_private_key_file()`. 312   `use_private_key()` or `use_private_key_file()`.
313   313  
314   @param certificate The certificate data. 314   @param certificate The certificate data.
315   315  
316   @param format The encoding format of the certificate data. 316   @param format The encoding format of the certificate data.
317   317  
318   @return Success. The certificate is recorded and decoded when the 318   @return Success. The certificate is recorded and decoded when the
319   native context is first built; a malformed certificate surfaces 319   native context is first built; a malformed certificate surfaces
320   as a handshake failure. 320   as a handshake failure.
321   321  
322   @see use_certificate_file 322   @see use_certificate_file
323   @see use_private_key 323   @see use_private_key
324   */ 324   */
325   [[nodiscard]] std::error_code 325   [[nodiscard]] std::error_code
326   use_certificate(std::string_view certificate, tls_file_format format); 326   use_certificate(std::string_view certificate, tls_file_format format);
327   327  
328   /** Load the entity certificate from a file. 328   /** Load the entity certificate from a file.
329   329  
330   Sets the certificate that identifies this endpoint to the peer. 330   Sets the certificate that identifies this endpoint to the peer.
331   For servers, this is the server certificate. For clients using 331   For servers, this is the server certificate. For clients using
332   mutual TLS, this is the client certificate. 332   mutual TLS, this is the client certificate.
333   333  
334   @param filename Path to the certificate file. 334   @param filename Path to the certificate file.
335   335  
336   @param format The encoding format of the file. 336   @param format The encoding format of the file.
337   337  
338   @return Success, or an error if the file could not be read. The 338   @return Success, or an error if the file could not be read. The
339   certificate is decoded when the native context is first built; 339   certificate is decoded when the native context is first built;
340   a malformed certificate surfaces as a handshake failure. 340   a malformed certificate surfaces as a handshake failure.
341   341  
342   @par Example 342   @par Example
343   @par !example use_certificate_file 343   @par !example use_certificate_file
344   344  
345   @see use_certificate 345   @see use_certificate
346   @see use_private_key_file 346   @see use_private_key_file
347   */ 347   */
348   [[nodiscard]] std::error_code 348   [[nodiscard]] std::error_code
349   use_certificate_file(std::string_view filename, tls_file_format format); 349   use_certificate_file(std::string_view filename, tls_file_format format);
350   350  
351   /** Load a certificate chain from a memory buffer. 351   /** Load a certificate chain from a memory buffer.
352   352  
353   Loads the entity certificate followed by intermediate CA certificates. 353   Loads the entity certificate followed by intermediate CA certificates.
354   The chain should be ordered from leaf to root (excluding the root). 354   The chain should be ordered from leaf to root (excluding the root).
355   This is the typical format for PEM certificate bundles. 355   This is the typical format for PEM certificate bundles.
356   356  
357   @param chain The certificate chain data in PEM format (concatenated 357   @param chain The certificate chain data in PEM format (concatenated
358   certificates). 358   certificates).
359   359  
360   @return Success. The chain is recorded and decoded when the native 360   @return Success. The chain is recorded and decoded when the native
361   context is first built; a malformed chain surfaces as a 361   context is first built; a malformed chain surfaces as a
362   handshake failure. 362   handshake failure.
363   363  
364   @see use_certificate_chain_file 364   @see use_certificate_chain_file
365   */ 365   */
366   [[nodiscard]] std::error_code use_certificate_chain(std::string_view chain); 366   [[nodiscard]] std::error_code use_certificate_chain(std::string_view chain);
367   367  
368   /** Load a certificate chain from a file. 368   /** Load a certificate chain from a file.
369   369  
370   Loads the entity certificate followed by intermediate CA certificates 370   Loads the entity certificate followed by intermediate CA certificates
371   from a PEM file. The file should contain concatenated PEM certificates 371   from a PEM file. The file should contain concatenated PEM certificates
372   ordered from leaf to root (excluding the root). 372   ordered from leaf to root (excluding the root).
373   373  
374   @param filename Path to the certificate chain file. 374   @param filename Path to the certificate chain file.
375   375  
376   @return Success, or an error if the file could not be read. The 376   @return Success, or an error if the file could not be read. The
377   chain is decoded when the native context is first built; a 377   chain is decoded when the native context is first built; a
378   malformed chain surfaces as a handshake failure. 378   malformed chain surfaces as a handshake failure.
379   379  
380   @par Example 380   @par Example
381   @par !example use_certificate_chain_file 381   @par !example use_certificate_chain_file
382   382  
383   @see use_certificate_chain 383   @see use_certificate_chain
384   */ 384   */
385   [[nodiscard]] std::error_code 385   [[nodiscard]] std::error_code
386   use_certificate_chain_file(std::string_view filename); 386   use_certificate_chain_file(std::string_view filename);
387   387  
388   /** Load the private key from a memory buffer. 388   /** Load the private key from a memory buffer.
389   389  
390   Sets the private key corresponding to the entity certificate. 390   Sets the private key corresponding to the entity certificate.
391   The key must match the certificate loaded via `use_certificate()` 391   The key must match the certificate loaded via `use_certificate()`
392   or `use_certificate_chain()`. 392   or `use_certificate_chain()`.
393   393  
394   If the key is encrypted, set a password callback via 394   If the key is encrypted, set a password callback via
395   `set_password_callback()` before calling this function. 395   `set_password_callback()` before calling this function.
396   396  
397   @param private_key The private key data. 397   @param private_key The private key data.
398   398  
399   @param format The encoding format of the key data. 399   @param format The encoding format of the key data.
400   400  
401   @return Success. The key is recorded and decoded when the native 401   @return Success. The key is recorded and decoded when the native
402   context is first built. Three faults surface only as a handshake 402   context is first built. Three faults surface only as a handshake
403   failure: a malformed key, a missing password callback for an 403   failure: a malformed key, a missing password callback for an
404   encrypted key, and a certificate mismatch. 404   encrypted key, and a certificate mismatch.
405   405  
406   @see use_private_key_file 406   @see use_private_key_file
407   @see set_password_callback 407   @see set_password_callback
408   */ 408   */
409   [[nodiscard]] std::error_code 409   [[nodiscard]] std::error_code
410   use_private_key(std::string_view private_key, tls_file_format format); 410   use_private_key(std::string_view private_key, tls_file_format format);
411   411  
412   /** Load the private key from a file. 412   /** Load the private key from a file.
413   413  
414   Sets the private key corresponding to the entity certificate. 414   Sets the private key corresponding to the entity certificate.
415   The key must match the certificate loaded via `use_certificate_file()` 415   The key must match the certificate loaded via `use_certificate_file()`
416   or `use_certificate_chain_file()`. 416   or `use_certificate_chain_file()`.
417   417  
418   If the key file is encrypted, set a password callback via 418   If the key file is encrypted, set a password callback via
419   `set_password_callback()` before calling this function. 419   `set_password_callback()` before calling this function.
420   420  
421   @param filename Path to the private key file. 421   @param filename Path to the private key file.
422   422  
423   @param format The encoding format of the file. 423   @param format The encoding format of the file.
424   424  
425   @return Success, or an error if the file could not be read. The 425   @return Success, or an error if the file could not be read. The
426   key is decoded when the native context is first built; a 426   key is decoded when the native context is first built; a
427   malformed key or a certificate mismatch surfaces as a 427   malformed key or a certificate mismatch surfaces as a
428   handshake failure. 428   handshake failure.
429   429  
430   @par Example 430   @par Example
431   @par !example use_private_key_file 431   @par !example use_private_key_file
432   432  
433   @see use_private_key 433   @see use_private_key
434   @see set_password_callback 434   @see set_password_callback
435   */ 435   */
436   [[nodiscard]] std::error_code 436   [[nodiscard]] std::error_code
437   use_private_key_file(std::string_view filename, tls_file_format format); 437   use_private_key_file(std::string_view filename, tls_file_format format);
438   438  
439   /** Load credentials from a PKCS#12 bundle in memory. 439   /** Load credentials from a PKCS#12 bundle in memory.
440   440  
441   PKCS#12 (also known as PFX) is a binary format that bundles a 441   PKCS#12 (also known as PFX) is a binary format that bundles a
442   certificate, private key, and optionally intermediate certificates 442   certificate, private key, and optionally intermediate certificates
443   into a single password-protected file. 443   into a single password-protected file.
444   444  
445   @param data The PKCS#12 bundle data. 445   @param data The PKCS#12 bundle data.
446   446  
447   @param passphrase The password protecting the bundle. 447   @param passphrase The password protecting the bundle.
448   448  
449   @return Success. The bundle is recorded and decoded into the 449   @return Success. The bundle is recorded and decoded into the
450   certificate, private key, and chain when the native context is 450   certificate, private key, and chain when the native context is
451   first built. A malformed bundle or a wrong passphrase surfaces as a 451   first built. A malformed bundle or a wrong passphrase surfaces as a
452   handshake failure. 452   handshake failure.
453   453  
454   @note Intermediate certificates inside the bundle are loaded and 454   @note Intermediate certificates inside the bundle are loaded and
455   sent during the handshake on both backends. 455   sent during the handshake on both backends.
456   456  
457   @see use_pkcs12_file 457   @see use_pkcs12_file
458   */ 458   */
459   [[nodiscard]] std::error_code 459   [[nodiscard]] std::error_code
460   use_pkcs12(std::string_view data, std::string_view passphrase); 460   use_pkcs12(std::string_view data, std::string_view passphrase);
461   461  
462   /** Load credentials from a PKCS#12 file. 462   /** Load credentials from a PKCS#12 file.
463   463  
464   PKCS#12 (also known as PFX) is a binary format that bundles a 464   PKCS#12 (also known as PFX) is a binary format that bundles a
465   certificate, private key, and optionally intermediate certificates 465   certificate, private key, and optionally intermediate certificates
466   into a single password-protected file. This is common on Windows 466   into a single password-protected file. This is common on Windows
467   and for certificates exported from browsers. 467   and for certificates exported from browsers.
468   468  
469   @param filename Path to the PKCS#12 file. 469   @param filename Path to the PKCS#12 file.
470   470  
471   @param passphrase The password protecting the file. 471   @param passphrase The password protecting the file.
472   472  
473   @return Success, or an error if the file could not be read. The 473   @return Success, or an error if the file could not be read. The
474   bundle is decoded when the native context is first built; a 474   bundle is decoded when the native context is first built; a
475   malformed bundle or wrong passphrase surfaces as a handshake 475   malformed bundle or wrong passphrase surfaces as a handshake
476   failure. 476   failure.
477   477  
478   @note Intermediate certificates inside the bundle are loaded and 478   @note Intermediate certificates inside the bundle are loaded and
479   sent during the handshake on both backends. 479   sent during the handshake on both backends.
480   480  
481   @par Example 481   @par Example
482   @par !example use_pkcs12_file 482   @par !example use_pkcs12_file
483   483  
484   @see use_pkcs12 484   @see use_pkcs12
485   */ 485   */
486   [[nodiscard]] std::error_code 486   [[nodiscard]] std::error_code
487   use_pkcs12_file(std::string_view filename, std::string_view passphrase); 487   use_pkcs12_file(std::string_view filename, std::string_view passphrase);
488   488  
489   // 489   //
490   // Trust Anchors 490   // Trust Anchors
491   // 491   //
492   492  
493   /** Add a certificate authority for peer verification. 493   /** Add a certificate authority for peer verification.
494   494  
495   Adds a single CA certificate to the trust store used for verifying 495   Adds a single CA certificate to the trust store used for verifying
496   peer certificates. Call this multiple times to add multiple CAs, 496   peer certificates. Call this multiple times to add multiple CAs,
497   or use `load_verify_file()` for a bundle. 497   or use `load_verify_file()` for a bundle.
498   498  
499   @param ca The CA certificate data in PEM format. 499   @param ca The CA certificate data in PEM format.
500   500  
501   @return Success. The certificate is recorded and decoded when the 501   @return Success. The certificate is recorded and decoded when the
502   native context is first built; a malformed certificate 502   native context is first built; a malformed certificate
503   surfaces as a handshake failure. 503   surfaces as a handshake failure.
504   504  
505   @see load_verify_file 505   @see load_verify_file
506   @see set_default_verify_paths 506   @see set_default_verify_paths
507   */ 507   */
508   [[nodiscard]] std::error_code 508   [[nodiscard]] std::error_code
509   add_certificate_authority(std::string_view ca); 509   add_certificate_authority(std::string_view ca);
510   510  
511   /** Load CA certificates from a file. 511   /** Load CA certificates from a file.
512   512  
513   Loads one or more CA certificates from a PEM file. The file may 513   Loads one or more CA certificates from a PEM file. The file may
514   contain multiple concatenated PEM certificates. 514   contain multiple concatenated PEM certificates.
515   515  
516   @param filename Path to a PEM file containing CA certificates. 516   @param filename Path to a PEM file containing CA certificates.
517   517  
518   @return Success, or an error if the file could not be read. The 518   @return Success, or an error if the file could not be read. The
519   certificates are decoded when the native context is first 519   certificates are decoded when the native context is first
520   built; malformed certificates surface as a handshake failure. 520   built; malformed certificates surface as a handshake failure.
521   521  
522   @par Example 522   @par Example
523   @par !example load_verify_file 523   @par !example load_verify_file
524   524  
525   @see add_certificate_authority 525   @see add_certificate_authority
526   @see add_verify_path 526   @see add_verify_path
527   */ 527   */
528   [[nodiscard]] std::error_code load_verify_file(std::string_view filename); 528   [[nodiscard]] std::error_code load_verify_file(std::string_view filename);
529   529  
530   /** Add a directory of CA certificates for verification. 530   /** Add a directory of CA certificates for verification.
531   531  
532   Adds a directory of CA certificates to the trust store. The 532   Adds a directory of CA certificates to the trust store. The
533   directory is applied when the native context is first built from 533   directory is applied when the native context is first built from
534   this context. 534   this context.
535   535  
536   The expected directory layout depends on the backend. OpenSSL 536   The expected directory layout depends on the backend. OpenSSL
537   performs on-demand lookups. Each certificate file must be named 537   performs on-demand lookups. Each certificate file must be named
538   by its subject-name hash, as generated by `openssl rehash` or 538   by its subject-name hash, as generated by `openssl rehash` or
539   `c_rehash`. WolfSSL loads every certificate file in the 539   `c_rehash`. WolfSSL loads every certificate file in the
540   directory. 540   directory.
541   541  
542   @param path Path to the directory of CA certificates. 542   @param path Path to the directory of CA certificates.
543   543  
544   @return Success. The path is recorded and applied when the native 544   @return Success. The path is recorded and applied when the native
545   context is built. A directory that cannot be read at that time is 545   context is built. A directory that cannot be read at that time is
546   skipped rather than reported here. 546   skipped rather than reported here.
547   547  
548   @par Example 548   @par Example
549   @par !example add_verify_path 549   @par !example add_verify_path
550   550  
551   @see load_verify_file 551   @see load_verify_file
552   @see set_default_verify_paths 552   @see set_default_verify_paths
553   */ 553   */
554   [[nodiscard]] std::error_code add_verify_path(std::string_view path); 554   [[nodiscard]] std::error_code add_verify_path(std::string_view path);
555   555  
556   /** Use the system default CA certificate store. 556   /** Use the system default CA certificate store.
557   557  
558   Configures the context to use the operating system's default 558   Configures the context to use the operating system's default
559   trust store for peer certificate verification. This is the 559   trust store for peer certificate verification. This is the
560   recommended approach for HTTPS clients connecting to public 560   recommended approach for HTTPS clients connecting to public
561   servers. 561   servers.
562   562  
563   The system store is loaded when the native context is first built 563   The system store is loaded when the native context is first built
564   from this context. For a verified-safe client, combine this with 564   from this context. For a verified-safe client, combine this with
565   `set_verify_mode( tls_verify_mode::peer )` and, when connecting by 565   `set_verify_mode( tls_verify_mode::peer )` and, when connecting by
566   name, `tls_stream::set_hostname()`. 566   name, `tls_stream::set_hostname()`.
567   567  
568   @return Success. The request is recorded and applied when the 568   @return Success. The request is recorded and applied when the
569   native context is built. A system store that cannot be loaded at 569   native context is built. A system store that cannot be loaded at
570   that time is skipped rather than reported here. A context that 570   that time is skipped rather than reported here. A context that
571   must reject unverified peers should therefore also use 571   must reject unverified peers should therefore also use
572   `set_verify_mode( tls_verify_mode::peer )`. 572   `set_verify_mode( tls_verify_mode::peer )`.
573   573  
574   @note The OpenSSL backend honors the `SSL_CERT_FILE` and 574   @note The OpenSSL backend honors the `SSL_CERT_FILE` and
575   `SSL_CERT_DIR` environment variables. The WolfSSL backend 575   `SSL_CERT_DIR` environment variables. The WolfSSL backend
576   requires a build with `WOLFSSL_SYS_CA_CERTS`; without it the 576   requires a build with `WOLFSSL_SYS_CA_CERTS`; without it the
577   system store is unavailable and this call has no effect. 577   system store is unavailable and this call has no effect.
578   578  
579   @par Example 579   @par Example
580   @par !example set_default_verify_paths 580   @par !example set_default_verify_paths
581   581  
582   @see load_verify_file 582   @see load_verify_file
583   @see add_verify_path 583   @see add_verify_path
584   @see set_verify_mode 584   @see set_verify_mode
585   */ 585   */
586   [[nodiscard]] std::error_code set_default_verify_paths(); 586   [[nodiscard]] std::error_code set_default_verify_paths();
587   587  
588   // 588   //
589   // Protocol Configuration 589   // Protocol Configuration
590   // 590   //
591   591  
592   /** Set the minimum TLS protocol version. 592   /** Set the minimum TLS protocol version.
593   593  
594   Connections reject protocol versions older than this. 594   Connections reject protocol versions older than this.
595   The default allows TLS 1.2 and newer. 595   The default allows TLS 1.2 and newer.
596   596  
597   @param v The minimum protocol version to accept. 597   @param v The minimum protocol version to accept.
598   598  
599   @return Success. The version is recorded and applied when the 599   @return Success. The version is recorded and applied when the
600   native context is first built. 600   native context is first built.
601   601  
602   @par Example 602   @par Example
603   @par !example set_min_protocol_version 603   @par !example set_min_protocol_version
604   604  
605   @see set_max_protocol_version 605   @see set_max_protocol_version
606   */ 606   */
607   [[nodiscard]] std::error_code set_min_protocol_version(tls_version v); 607   [[nodiscard]] std::error_code set_min_protocol_version(tls_version v);
608   608  
609   /** Set the maximum TLS protocol version. 609   /** Set the maximum TLS protocol version.
610   610  
611   Connections do not negotiate protocol versions newer than this. 611   Connections do not negotiate protocol versions newer than this.
612   The default allows the newest supported version. 612   The default allows the newest supported version.
613   613  
614   @param v The maximum protocol version to accept. 614   @param v The maximum protocol version to accept.
615   615  
616   @return Success. The version is recorded and applied when the 616   @return Success. The version is recorded and applied when the
617   native context is first built. 617   native context is first built.
618   618  
619   @note On WolfSSL the ceiling is applied by selecting a 619   @note On WolfSSL the ceiling is applied by selecting a
620   version-specific method, because no native set-max API exists. An 620   version-specific method, because no native set-max API exists. An
621   invalid window, where the minimum exceeds the maximum, yields a 621   invalid window, where the minimum exceeds the maximum, yields a
622   context that fails the handshake. 622   context that fails the handshake.
623   623  
624   @see set_min_protocol_version 624   @see set_min_protocol_version
625   */ 625   */
626   [[nodiscard]] std::error_code set_max_protocol_version(tls_version v); 626   [[nodiscard]] std::error_code set_max_protocol_version(tls_version v);
627   627  
628   /** Set the allowed cipher suites. 628   /** Set the allowed cipher suites.
629   629  
630   Configures which cipher suites may be used for connections. 630   Configures which cipher suites may be used for connections.
631   The format is backend-specific but typically follows OpenSSL 631   The format is backend-specific but typically follows OpenSSL
632   cipher list syntax. 632   cipher list syntax.
633   633  
634   @param ciphers The cipher suite specification string. 634   @param ciphers The cipher suite specification string.
635   635  
636   @return Success. The string is recorded and applied when the 636   @return Success. The string is recorded and applied when the
637   native context is first built; an invalid cipher string 637   native context is first built; an invalid cipher string
638   surfaces as a handshake failure. 638   surfaces as a handshake failure.
639   639  
640   @par Example 640   @par Example
641   @par !example set_ciphersuites 641   @par !example set_ciphersuites
642   642  
643   @note This configures cipher suites for TLS 1.2 and below. For 643   @note This configures cipher suites for TLS 1.2 and below. For
644   TLS 1.3, use @ref set_ciphersuites_tls13. 644   TLS 1.3, use @ref set_ciphersuites_tls13.
645   */ 645   */
646   [[nodiscard]] std::error_code set_ciphersuites(std::string_view ciphers); 646   [[nodiscard]] std::error_code set_ciphersuites(std::string_view ciphers);
647   647  
648   /** Set the allowed TLS 1.3 cipher suites. 648   /** Set the allowed TLS 1.3 cipher suites.
649   649  
650   TLS 1.3 uses a distinct, fixed set of cipher suites configured 650   TLS 1.3 uses a distinct, fixed set of cipher suites configured
651   separately from earlier versions. The format is a colon-separated 651   separately from earlier versions. The format is a colon-separated
652   list of TLS 1.3 suite names. 652   list of TLS 1.3 suite names.
653   653  
654   @param ciphers The TLS 1.3 cipher suite list. 654   @param ciphers The TLS 1.3 cipher suite list.
655   655  
656   @return Success. The string is recorded and applied when the 656   @return Success. The string is recorded and applied when the
657   native context is first built; an invalid cipher string 657   native context is first built; an invalid cipher string
658   surfaces as a handshake failure. 658   surfaces as a handshake failure.
659   659  
660   @par Example 660   @par Example
661   @par !example set_ciphersuites_tls13 661   @par !example set_ciphersuites_tls13
662   662  
663   @note On the WolfSSL backend, TLS 1.2 and TLS 1.3 suites share a 663   @note On the WolfSSL backend, TLS 1.2 and TLS 1.3 suites share a
664   single cipher list; this call and @ref set_ciphersuites are 664   single cipher list; this call and @ref set_ciphersuites are
665   merged into one list. 665   merged into one list.
666   666  
667   @see set_ciphersuites 667   @see set_ciphersuites
668   */ 668   */
669   [[nodiscard]] std::error_code 669   [[nodiscard]] std::error_code
670   set_ciphersuites_tls13(std::string_view ciphers); 670   set_ciphersuites_tls13(std::string_view ciphers);
671   671  
672   /** Set the ALPN protocol list. 672   /** Set the ALPN protocol list.
673   673  
674   Configures Application-Layer Protocol Negotiation (ALPN) for 674   Configures Application-Layer Protocol Negotiation (ALPN) for
675   the connection. ALPN is used to negotiate which application 675   the connection. ALPN is used to negotiate which application
676   protocol to use over the TLS connection (e.g., "h2" for HTTP/2, 676   protocol to use over the TLS connection (e.g., "h2" for HTTP/2,
677   "http/1.1" for HTTP/1.1). 677   "http/1.1" for HTTP/1.1).
678   678  
679   The protocols are tried in preference order (first = highest). 679   The protocols are tried in preference order (first = highest).
680   680  
681   @param protocols Ordered list of protocol identifiers. 681   @param protocols Ordered list of protocol identifiers.
682   682  
683   @return Success, or an error if ALPN configuration fails. 683   @return Success, or an error if ALPN configuration fails.
684   684  
685   @note Read the negotiated protocol after the handshake via 685   @note Read the negotiated protocol after the handshake via
686   @ref tls_stream::alpn_protocol. On WolfSSL, ALPN requires a 686   @ref tls_stream::alpn_protocol. On WolfSSL, ALPN requires a
687   build with `HAVE_ALPN`; without it, offering protocols fails 687   build with `HAVE_ALPN`; without it, offering protocols fails
688   the handshake with `std::errc::function_not_supported` rather 688   the handshake with `std::errc::function_not_supported` rather
689   than negotiate nothing silently. 689   than negotiate nothing silently.
690   690  
691   @par Example 691   @par Example
692   @par !example set_alpn 692   @par !example set_alpn
693   */ 693   */
694   [[nodiscard]] std::error_code 694   [[nodiscard]] std::error_code
695   set_alpn(std::initializer_list<std::string_view> protocols); 695   set_alpn(std::initializer_list<std::string_view> protocols);
696   696  
697   // 697   //
698   // Certificate Verification 698   // Certificate Verification
699   // 699   //
700   700  
701   /** Set the peer certificate verification mode. 701   /** Set the peer certificate verification mode.
702   702  
703   Controls whether and how peer certificates are verified during 703   Controls whether and how peer certificates are verified during
704   the TLS handshake. 704   the TLS handshake.
705   705  
706   @param mode The verification mode to use. 706   @param mode The verification mode to use.
707   707  
708   @return Success. The mode is recorded and applied when the native 708   @return Success. The mode is recorded and applied when the native
709   context is first built. 709   context is first built.
710   710  
711   @par Example 711   @par Example
712   @par !example set_verify_mode 712   @par !example set_verify_mode
713   713  
714   @see tls_verify_mode 714   @see tls_verify_mode
715   */ 715   */
716   [[nodiscard]] std::error_code set_verify_mode(tls_verify_mode mode); 716   [[nodiscard]] std::error_code set_verify_mode(tls_verify_mode mode);
717   717  
718   /** Set the maximum certificate chain verification depth. 718   /** Set the maximum certificate chain verification depth.
719   719  
720   Limits how many intermediate certificates can appear between 720   Limits how many intermediate certificates can appear between
721   the peer certificate and a trusted root. The default is 721   the peer certificate and a trusted root. The default is
722   typically 100, which is sufficient for most certificate chains. 722   typically 100, which is sufficient for most certificate chains.
723   723  
724   @param depth Maximum number of intermediate certificates allowed. 724   @param depth Maximum number of intermediate certificates allowed.
725   725  
726   @return Success. The depth is recorded and applied when the native 726   @return Success. The depth is recorded and applied when the native
727   context is first built. 727   context is first built.
728   728  
729   @par Example 729   @par Example
730   @par !example set_verify_depth 730   @par !example set_verify_depth
731   */ 731   */
732   [[nodiscard]] std::error_code set_verify_depth(int depth); 732   [[nodiscard]] std::error_code set_verify_depth(int depth);
733   733  
734   /** Set a custom certificate verification callback. 734   /** Set a custom certificate verification callback.
735   735  
736   Installs a callback that is invoked during certificate chain 736   Installs a callback that is invoked during certificate chain
737   verification. The callback can perform additional validation 737   verification. The callback can perform additional validation
738   beyond the standard checks and can override verification 738   beyond the standard checks and can override verification
739   results. 739   results.
740   740  
741   The callback receives the built-in verification result so far and 741   The callback receives the built-in verification result so far and
742   a `verify_context` describing the certificate being verified. Return 742   a `verify_context` describing the certificate being verified. Return
743   `true` to accept the certificate, `false` to reject. Inspect the 743   `true` to accept the certificate, `false` to reject. Inspect the
744   certificate portably via `verify_context::certificate()` (its DER 744   certificate portably via `verify_context::certificate()` (its DER
745   encoding) — for example to pin a specific certificate. 745   encoding) — for example to pin a specific certificate.
746   746  
747   @par Backend Support 747   @par Backend Support
748   748  
749   The exact set of certificates the callback sees differs by backend: 749   The exact set of certificates the callback sees differs by backend:
750   750  
751   - OpenSSL: the callback runs once per certificate in the chain, 751   - OpenSSL: the callback runs once per certificate in the chain,
752   including certificates that passed the built-in checks. It can 752   including certificates that passed the built-in checks. It can
753   therefore relax verification by returning `true` for a 753   therefore relax verification by returning `true` for a
754   certificate the library rejected. It can also tighten 754   certificate the library rejected. It can also tighten
755   verification by returning `false` for a certificate the library 755   verification by returning `false` for a certificate the library
756   accepted, as pinning does. 756   accepted, as pinning does.
757   - WolfSSL built with `WOLFSSL_ALWAYS_VERIFY_CB` (implied by 757   - WolfSSL built with `WOLFSSL_ALWAYS_VERIFY_CB` (implied by
758   `--enable-opensslextra`): same as OpenSSL. 758   `--enable-opensslextra`): same as OpenSSL.
759   - WolfSSL without that option: the library invokes the callback 759   - WolfSSL without that option: the library invokes the callback
760   only on verification *failure*, so it cannot be honored on a 760   only on verification *failure*, so it cannot be honored on a
761   successful handshake. Silently ignoring a verification-tightening 761   successful handshake. Silently ignoring a verification-tightening
762   callback would fail open. On such a build, a context that carries 762   callback would fail open. On such a build, a context that carries
763   a callback instead **fails the handshake** with 763   a callback instead **fails the handshake** with
764   `std::errc::function_not_supported`. Rebuild 764   `std::errc::function_not_supported`. Rebuild
765   WolfSSL with `WOLFSSL_ALWAYS_VERIFY_CB`, or omit the callback. 765   WolfSSL with `WOLFSSL_ALWAYS_VERIFY_CB`, or omit the callback.
766   766  
767   @tparam Callback A callable with signature 767   @tparam Callback A callable with signature
768   `bool( bool preverified, verify_context& ctx )`. 768   `bool( bool preverified, verify_context& ctx )`.
769   769  
770   @param callback The verification callback. Recorded here and 770   @param callback The verification callback. Recorded here and
771   applied during the handshake; on a WolfSSL build that 771   applied during the handshake; on a WolfSSL build that
772   cannot honor it, the handshake fails with 772   cannot honor it, the handshake fails with
773   `std::errc::function_not_supported` (see Backend Support). 773   `std::errc::function_not_supported` (see Backend Support).
774   774  
775   @par Example 775   @par Example
776   @par !example set_verify_callback 776   @par !example set_verify_callback
777   777  
778   @see verify_context 778   @see verify_context
779   @see set_verify_mode 779   @see set_verify_mode
780   */ 780   */
781   template<typename Callback> 781   template<typename Callback>
782   void set_verify_callback(Callback callback); 782   void set_verify_callback(Callback callback);
783   783  
784   /** Set a callback for Server Name Indication (SNI). 784   /** Set a callback for Server Name Indication (SNI).
785   785  
786   For server connections, this callback is invoked during the TLS 786   For server connections, this callback is invoked during the TLS
787   handshake when a client sends an SNI extension. The callback 787   handshake when a client sends an SNI extension. The callback
788   receives the requested hostname and can accept or reject the 788   receives the requested hostname and can accept or reject the
789   connection. 789   connection.
790   790  
791   @tparam Callback A callable with signature 791   @tparam Callback A callable with signature
792   `bool( std::string_view hostname )`. 792   `bool( std::string_view hostname )`.
793   793  
794   @param callback The SNI callback. Return `true` to accept the 794   @param callback The SNI callback. Return `true` to accept the
795   connection or `false` to reject it with an alert. 795   connection or `false` to reject it with an alert.
796   796  
797   @par Example 797   @par Example
798   @par !example set_servername_callback 798   @par !example set_servername_callback
799   799  
800   @note For virtual hosting with different certificates per hostname, 800   @note For virtual hosting with different certificates per hostname,
801   create separate contexts and select the appropriate one before 801   create separate contexts and select the appropriate one before
802   creating the TLS stream. 802   creating the TLS stream.
803   803  
804   @see tls_stream::set_hostname 804   @see tls_stream::set_hostname
805   */ 805   */
806   template<typename Callback> 806   template<typename Callback>
807   void set_servername_callback(Callback callback); 807   void set_servername_callback(Callback callback);
808   808  
809   private: 809   private:
810   void set_servername_callback_impl( 810   void set_servername_callback_impl(
811   std::function<bool(std::string_view)> callback); 811   std::function<bool(std::string_view)> callback);
812   812  
813   void set_password_callback_impl( 813   void set_password_callback_impl(
814   std::function<std::string(std::size_t, tls_password_purpose)> callback); 814   std::function<std::string(std::size_t, tls_password_purpose)> callback);
815   815  
816   void set_verify_callback_impl( 816   void set_verify_callback_impl(
817   std::function<bool(bool, verify_context&)> callback); 817   std::function<bool(bool, verify_context&)> callback);
818   818  
819   public: 819   public:
820   // 820   //
821   // Revocation Checking 821   // Revocation Checking
822   // 822   //
823   823  
824   /** Add a Certificate Revocation List from memory. 824   /** Add a Certificate Revocation List from memory.
825   825  
826   Adds a CRL to the verification store for checking whether 826   Adds a CRL to the verification store for checking whether
827   certificates are revoked. CRLs are typically fetched 827   certificates are revoked. CRLs are typically fetched
828   from the URLs in a certificate's CRL Distribution Points 828   from the URLs in a certificate's CRL Distribution Points
829   extension. 829   extension.
830   830  
831   @param crl The CRL data in DER or PEM format. 831   @param crl The CRL data in DER or PEM format.
832   832  
833   @return Success. The CRL is recorded and decoded when the native 833   @return Success. The CRL is recorded and decoded when the native
834   context is first built; a malformed CRL surfaces as a 834   context is first built; a malformed CRL surfaces as a
835   handshake failure. 835   handshake failure.
836   836  
837   @note CRLs are consulted only when a revocation policy is set via 837   @note CRLs are consulted only when a revocation policy is set via
838   @ref set_revocation_policy. On WolfSSL, CRL checking requires a 838   @ref set_revocation_policy. On WolfSSL, CRL checking requires a
839   build with `HAVE_CRL`; without it, supplying a CRL or a 839   build with `HAVE_CRL`; without it, supplying a CRL or a
840   revocation policy fails the handshake with 840   revocation policy fails the handshake with
841   `std::errc::function_not_supported`. 841   `std::errc::function_not_supported`.
842   842  
843   @see add_crl_file 843   @see add_crl_file
844   @see set_revocation_policy 844   @see set_revocation_policy
845   */ 845   */
846   [[nodiscard]] std::error_code add_crl(std::string_view crl); 846   [[nodiscard]] std::error_code add_crl(std::string_view crl);
847   847  
848   /** Add a Certificate Revocation List from a file. 848   /** Add a Certificate Revocation List from a file.
849   849  
850   Adds a CRL to the verification store for checking whether 850   Adds a CRL to the verification store for checking whether
851   certificates are revoked. 851   certificates are revoked.
852   852  
853   @param filename Path to a CRL file (DER or PEM format). 853   @param filename Path to a CRL file (DER or PEM format).
854   854  
855   @return Success, or an error if the file could not be read. The 855   @return Success, or an error if the file could not be read. The
856   CRL is decoded when the native context is first built; a 856   CRL is decoded when the native context is first built; a
857   malformed CRL surfaces as a handshake failure. 857   malformed CRL surfaces as a handshake failure.
858   858  
859   @note CRLs are consulted only when a revocation policy is set via 859   @note CRLs are consulted only when a revocation policy is set via
860   @ref set_revocation_policy (WolfSSL requires a `HAVE_CRL` 860   @ref set_revocation_policy (WolfSSL requires a `HAVE_CRL`
861   build). 861   build).
862   862  
863   @par Example 863   @par Example
864   @par !example add_crl_file 864   @par !example add_crl_file
865   865  
866   @see add_crl 866   @see add_crl
867   @see set_revocation_policy 867   @see set_revocation_policy
868   */ 868   */
869   [[nodiscard]] std::error_code add_crl_file(std::string_view filename); 869   [[nodiscard]] std::error_code add_crl_file(std::string_view filename);
870   870  
871   /** Set the certificate revocation checking policy. 871   /** Set the certificate revocation checking policy.
872   872  
873   Controls how certificate revocation status is checked during 873   Controls how certificate revocation status is checked during
874   verification via CRLs. 874   verification via CRLs.
875   875  
876   @param policy The revocation checking policy. 876   @param policy The revocation checking policy.
877   877  
878   @par Example 878   @par Example
879   @par !example set_revocation_policy 879   @par !example set_revocation_policy
880   880  
881   @note Revocation is checked via CRLs supplied with @ref add_crl / 881   @note Revocation is checked via CRLs supplied with @ref add_crl /
882   @ref add_crl_file. `soft_fail` accepts a certificate whose 882   @ref add_crl_file. `soft_fail` accepts a certificate whose
883   status cannot be determined (missing/expired CRL) but rejects 883   status cannot be determined (missing/expired CRL) but rejects
884   one that is actually revoked; `hard_fail` also rejects unknown 884   one that is actually revoked; `hard_fail` also rejects unknown
885   status. OCSP-based revocation is not available (see the TLS 885   status. OCSP-based revocation is not available (see the TLS
886   guide). On WolfSSL a non-disabled policy requires a `HAVE_CRL` 886   guide). On WolfSSL a non-disabled policy requires a `HAVE_CRL`
887   build, else the handshake fails with 887   build, else the handshake fails with
888   `std::errc::function_not_supported`. 888   `std::errc::function_not_supported`.
889   889  
890   @see tls_revocation_policy 890   @see tls_revocation_policy
891   @see add_crl 891   @see add_crl
892   */ 892   */
893   void set_revocation_policy(tls_revocation_policy policy); 893   void set_revocation_policy(tls_revocation_policy policy);
894   894  
895   // 895   //
896   // Password Handling 896   // Password Handling
897   // 897   //
898   898  
899   /** Set the password callback for encrypted keys. 899   /** Set the password callback for encrypted keys.
900   900  
901   Installs a callback that provides passwords for encrypted 901   Installs a callback that provides passwords for encrypted
902   private keys and PKCS#12 files. The callback is invoked when 902   private keys and PKCS#12 files. The callback is invoked when
903   loading encrypted key material. 903   loading encrypted key material.
904   904  
905   @tparam Callback A callable with signature 905   @tparam Callback A callable with signature
906   `std::string( std::size_t max_length, tls_password_purpose purpose )`. 906   `std::string( std::size_t max_length, tls_password_purpose purpose )`.
907   907  
908   @param callback The password callback. It receives the maximum 908   @param callback The password callback. It receives the maximum
909   password length and the purpose (reading or writing), and 909   password length and the purpose (reading or writing), and
910   returns the password string. 910   returns the password string.
911   911  
912   @par Example 912   @par Example
913   @par !example set_password_callback 913   @par !example set_password_callback
914   914  
915   @see tls_password_purpose 915   @see tls_password_purpose
916   */ 916   */
917   template<typename Callback> 917   template<typename Callback>
918   void set_password_callback(Callback callback); 918   void set_password_callback(Callback callback);
919   }; 919   };
920   #ifdef _MSC_VER 920   #ifdef _MSC_VER
921   #pragma warning(pop) 921   #pragma warning(pop)
922   #endif 922   #endif
923   923  
924   template<typename Callback> 924   template<typename Callback>
925   void 925   void
HITCBC 926   1 tls_context::set_servername_callback(Callback callback) 926   1 tls_context::set_servername_callback(Callback callback)
927   { 927   {
HITCBC 928   1 set_servername_callback_impl(std::move(callback)); 928   1 set_servername_callback_impl(std::move(callback));
HITCBC 929   1 } 929   1 }
930   930  
931   template<typename Callback> 931   template<typename Callback>
932   void 932   void
HITCBC 933   4 tls_context::set_password_callback(Callback callback) 933   4 tls_context::set_password_callback(Callback callback)
934   { 934   {
HITCBC 935   4 set_password_callback_impl(std::move(callback)); 935   4 set_password_callback_impl(std::move(callback));
HITCBC 936   4 } 936   4 }
937   937  
938   template<typename Callback> 938   template<typename Callback>
939   void 939   void
HITCBC 940   2 tls_context::set_verify_callback(Callback callback) 940   2 tls_context::set_verify_callback(Callback callback)
941   { 941   {
HITCBC 942   2 set_verify_callback_impl(std::move(callback)); 942   2 set_verify_callback_impl(std::move(callback));
HITCBC 943   2 } 943   2 }
944   944  
945   } // namespace boost::corosio 945   } // namespace boost::corosio
946   946  
947   #endif 947   #endif