1 /**
2  * \file x509_csr.h
3  *
4  * \brief X.509 certificate signing request parsing and writing
5  */
6 /*
7  *  Copyright The Mbed TLS Contributors
8  *  SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
9  */
10 #ifndef MBEDTLS_X509_CSR_H
11 #define MBEDTLS_X509_CSR_H
12 #include "mbedtls/private_access.h"
13 
14 #include "mbedtls/build_info.h"
15 
16 #include "mbedtls/x509.h"
17 
18 #ifdef __cplusplus
19 extern "C" {
20 #endif
21 
22 /**
23  * \addtogroup x509_module
24  * \{ */
25 
26 /**
27  * \name Structures and functions for X.509 Certificate Signing Requests (CSR)
28  * \{
29  */
30 
31 /**
32  * Certificate Signing Request (CSR) structure.
33  *
34  * Some fields of this structure are publicly readable. Do not modify
35  * them except via Mbed TLS library functions: the effect of modifying
36  * those fields or the data that those fields point to is unspecified.
37  */
38 typedef struct mbedtls_x509_csr {
39     mbedtls_x509_buf raw;           /**< The raw CSR data (DER). */
40     mbedtls_x509_buf cri;           /**< The raw CertificateRequestInfo body (DER). */
41 
42     int version;            /**< CSR version (1=v1). */
43 
44     mbedtls_x509_buf  subject_raw;  /**< The raw subject data (DER). */
45     mbedtls_x509_name subject;      /**< The parsed subject data (named information object). */
46 
47     mbedtls_pk_context pk;          /**< Container for the public key context. */
48 
49     unsigned int key_usage;     /**< Optional key usage extension value: See the values in x509.h */
50     unsigned char ns_cert_type; /**< Optional Netscape certificate type extension value: See the values in x509.h */
51     mbedtls_x509_sequence subject_alt_names; /**< Optional list of raw entries of Subject Alternative Names extension. These can be later parsed by mbedtls_x509_parse_subject_alt_name. */
52 
53     int MBEDTLS_PRIVATE(ext_types);              /**< Bit string containing detected and parsed extensions */
54 
55     mbedtls_x509_buf sig_oid;
56     mbedtls_x509_buf MBEDTLS_PRIVATE(sig);
57     mbedtls_md_type_t MBEDTLS_PRIVATE(sig_md);       /**< Internal representation of the MD algorithm of the signature algorithm, e.g. MBEDTLS_MD_SHA256 */
58     mbedtls_pk_sigalg_t MBEDTLS_PRIVATE(sig_pk);       /**< Internal representation of the Public Key algorithm of the signature algorithm, e.g. MBEDTLS_PK_RSA */
59 }
60 mbedtls_x509_csr;
61 
62 /**
63  * Container for writing a CSR
64  */
65 typedef struct mbedtls_x509write_csr {
66     mbedtls_pk_context *MBEDTLS_PRIVATE(key);
67     mbedtls_asn1_named_data *MBEDTLS_PRIVATE(subject);
68     mbedtls_md_type_t MBEDTLS_PRIVATE(md_alg);
69     mbedtls_asn1_named_data *MBEDTLS_PRIVATE(extensions);
70 }
71 mbedtls_x509write_csr;
72 
73 #if defined(MBEDTLS_X509_CSR_PARSE_C)
74 /**
75  * \brief          Load a Certificate Signing Request (CSR) in DER format
76  *
77  * \note           Any unsupported requested extensions are silently
78  *                 ignored, unless the critical flag is set, in which case
79  *                 the CSR is rejected.
80  *
81  * \note           The PSA crypto subsystem must have been initialized by
82  *                 calling psa_crypto_init() before calling this function.
83  *
84  * \param csr      CSR context to fill
85  * \param buf      buffer holding the CRL data
86  * \param buflen   size of the buffer
87  *
88  * \return         0 if successful, or a specific X509 error code
89  */
90 int mbedtls_x509_csr_parse_der(mbedtls_x509_csr *csr,
91                                const unsigned char *buf, size_t buflen);
92 
93 /**
94  * \brief          The type of certificate extension callbacks.
95  *
96  *                 Callbacks of this type are passed to and used by the
97  *                 mbedtls_x509_csr_parse_der_with_ext_cb() routine when
98  *                 it encounters either an unsupported extension.
99  *                 Future versions of the library may invoke the callback
100  *                 in other cases, if and when the need arises.
101  *
102  * \param p_ctx    An opaque context passed to the callback.
103  * \param csr      The CSR being parsed.
104  * \param oid      The OID of the extension.
105  * \param critical Whether the extension is critical.
106  * \param p        Pointer to the start of the extension value
107  *                 (the content of the OCTET STRING).
108  * \param end      End of extension value.
109  *
110  * \note           The callback must fail and return a negative error code
111  *                 if it can not parse or does not support the extension.
112  *                 When the callback fails to parse a critical extension
113  *                 mbedtls_x509_csr_parse_der_with_ext_cb() also fails.
114  *                 When the callback fails to parse a non critical extension
115  *                 mbedtls_x509_csr_parse_der_with_ext_cb() simply skips
116  *                 the extension and continues parsing.
117  *
118  * \return         \c 0 on success.
119  * \return         A negative error code on failure.
120  */
121 typedef int (*mbedtls_x509_csr_ext_cb_t)(void *p_ctx,
122                                          mbedtls_x509_csr const *csr,
123                                          mbedtls_x509_buf const *oid,
124                                          int critical,
125                                          const unsigned char *p,
126                                          const unsigned char *end);
127 
128 /**
129  * \brief          Load a Certificate Signing Request (CSR) in DER format
130  *
131  * \note           Any unsupported requested extensions are silently
132  *                 ignored, unless the critical flag is set, in which case
133  *                 the result of the callback function decides whether
134  *                 CSR is rejected.
135  *
136  * \note           The PSA crypto subsystem must have been initialized by
137  *                 calling psa_crypto_init() before calling this function.
138  *
139  * \param csr      CSR context to fill
140  * \param buf      buffer holding the CRL data
141  * \param buflen   size of the buffer
142  * \param cb       A callback invoked for every unsupported certificate
143  *                 extension.
144  * \param p_ctx    An opaque context passed to the callback.
145  *
146  * \return         0 if successful, or a specific X509 error code
147  */
148 int mbedtls_x509_csr_parse_der_with_ext_cb(mbedtls_x509_csr *csr,
149                                            const unsigned char *buf, size_t buflen,
150                                            mbedtls_x509_csr_ext_cb_t cb,
151                                            void *p_ctx);
152 
153 /**
154  * \brief          Load a Certificate Signing Request (CSR), DER or PEM format
155  *
156  * \note           See notes for \c mbedtls_x509_csr_parse_der()
157  *
158  * \note           The PSA crypto subsystem must have been initialized by
159  *                 calling psa_crypto_init() before calling this function.
160  *
161  * \param csr      CSR context to fill
162  * \param buf      buffer holding the CRL data
163  * \param buflen   size of the buffer
164  *                 (including the terminating null byte for PEM data)
165  *
166  * \return         0 if successful, or a specific X509 or PEM error code
167  */
168 int mbedtls_x509_csr_parse(mbedtls_x509_csr *csr, const unsigned char *buf, size_t buflen);
169 
170 #if defined(MBEDTLS_FS_IO)
171 /**
172  * \brief          Load a Certificate Signing Request (CSR)
173  *
174  * \note           See notes for \c mbedtls_x509_csr_parse()
175  *
176  * \param csr      CSR context to fill
177  * \param path     filename to read the CSR from
178  *
179  * \return         0 if successful, or a specific X509 or PEM error code
180  */
181 int mbedtls_x509_csr_parse_file(mbedtls_x509_csr *csr, const char *path);
182 #endif /* MBEDTLS_FS_IO */
183 
184 #if !defined(MBEDTLS_X509_REMOVE_INFO)
185 /**
186  * \brief          Returns an informational string about the
187  *                 CSR.
188  *
189  * \param buf      Buffer to write to
190  * \param size     Maximum size of buffer
191  * \param prefix   A line prefix
192  * \param csr      The X509 CSR to represent
193  *
194  * \return         The length of the string written (not including the
195  *                 terminated nul byte), or a negative error code.
196  */
197 int mbedtls_x509_csr_info(char *buf, size_t size, const char *prefix,
198                           const mbedtls_x509_csr *csr);
199 #endif /* !MBEDTLS_X509_REMOVE_INFO */
200 
201 /**
202  * \brief          Initialize a CSR
203  *
204  * \param csr      CSR to initialize
205  */
206 void mbedtls_x509_csr_init(mbedtls_x509_csr *csr);
207 
208 /**
209  * \brief          Unallocate all CSR data
210  *
211  * \param csr      CSR to free
212  */
213 void mbedtls_x509_csr_free(mbedtls_x509_csr *csr);
214 #endif /* MBEDTLS_X509_CSR_PARSE_C */
215 
216 /** \} name Structures and functions for X.509 Certificate Signing Requests (CSR) */
217 
218 #if defined(MBEDTLS_X509_CSR_WRITE_C)
219 /**
220  * \brief           Initialize a CSR context
221  *
222  * \param ctx       CSR context to initialize
223  */
224 void mbedtls_x509write_csr_init(mbedtls_x509write_csr *ctx);
225 
226 /**
227  * \brief           Set the subject name for a CSR
228  *                  Subject names should contain a comma-separated list
229  *                  of OID types and values:
230  *                  e.g. "C=UK,O=ARM,CN=Mbed TLS Server 1"
231  *
232  * \param ctx           CSR context to use
233  * \param subject_name  subject name to set
234  *
235  * \return          0 if subject name was parsed successfully, or
236  *                  a specific error code
237  */
238 int mbedtls_x509write_csr_set_subject_name(mbedtls_x509write_csr *ctx,
239                                            const char *subject_name);
240 
241 /**
242  * \brief           Set the key for a CSR (public key will be included,
243  *                  private key used to sign the CSR when writing it)
244  *
245  * \param ctx       CSR context to use
246  * \param key       Asymmetric key to include
247  */
248 void mbedtls_x509write_csr_set_key(mbedtls_x509write_csr *ctx, mbedtls_pk_context *key);
249 
250 /**
251  * \brief           Set the MD algorithm to use for the signature
252  *                  (e.g. MBEDTLS_MD_SHA1)
253  *
254  * \param ctx       CSR context to use
255  * \param md_alg    MD algorithm to use
256  */
257 void mbedtls_x509write_csr_set_md_alg(mbedtls_x509write_csr *ctx, mbedtls_md_type_t md_alg);
258 
259 /**
260  * \brief           Set the Key Usage Extension flags
261  *                  (e.g. MBEDTLS_X509_KU_DIGITAL_SIGNATURE | MBEDTLS_X509_KU_KEY_CERT_SIGN)
262  *
263  * \param ctx       CSR context to use
264  * \param key_usage key usage flags to set
265  *
266  * \return          0 if successful, or MBEDTLS_ERR_X509_ALLOC_FAILED
267  *
268  * \note            The <code>decipherOnly</code> flag from the Key Usage
269  *                  extension is represented by bit 8 (i.e.
270  *                  <code>0x8000</code>), which cannot typically be represented
271  *                  in an unsigned char. Therefore, the flag
272  *                  <code>decipherOnly</code> (i.e.
273  *                  #MBEDTLS_X509_KU_DECIPHER_ONLY) cannot be set using this
274  *                  function.
275  */
276 int mbedtls_x509write_csr_set_key_usage(mbedtls_x509write_csr *ctx, unsigned char key_usage);
277 
278 /**
279  * \brief           Set Subject Alternative Name
280  *
281  * \param ctx       CSR context to use
282  * \param san_list  List of SAN values
283  *
284  * \return          0 if successful, or MBEDTLS_ERR_X509_ALLOC_FAILED
285  *
286  * \note            Only "dnsName", "uniformResourceIdentifier" and "otherName",
287  *                  as defined in RFC 5280, are supported.
288  */
289 int mbedtls_x509write_csr_set_subject_alternative_name(mbedtls_x509write_csr *ctx,
290                                                        const mbedtls_x509_san_list *san_list);
291 
292 /**
293  * \brief           Set the Netscape Cert Type flags
294  *                  (e.g. MBEDTLS_X509_NS_CERT_TYPE_SSL_CLIENT | MBEDTLS_X509_NS_CERT_TYPE_EMAIL)
295  *
296  * \param ctx           CSR context to use
297  * \param ns_cert_type  Netscape Cert Type flags to set
298  *
299  * \return          0 if successful, or MBEDTLS_ERR_X509_ALLOC_FAILED
300  */
301 int mbedtls_x509write_csr_set_ns_cert_type(mbedtls_x509write_csr *ctx,
302                                            unsigned char ns_cert_type);
303 
304 /**
305  * \brief           Generic function to add to or replace an extension in the
306  *                  CSR
307  *
308  * \param ctx       CSR context to use
309  * \param oid       OID of the extension
310  * \param oid_len   length of the OID
311  * \param critical  Set to 1 to mark the extension as critical, 0 otherwise.
312  * \param val       value of the extension OCTET STRING
313  * \param val_len   length of the value data
314  *
315  * \return          0 if successful, or a MBEDTLS_ERR_X509_ALLOC_FAILED
316  */
317 int mbedtls_x509write_csr_set_extension(mbedtls_x509write_csr *ctx,
318                                         const char *oid, size_t oid_len,
319                                         int critical,
320                                         const unsigned char *val, size_t val_len);
321 
322 /**
323  * \brief           Free the contents of a CSR context
324  *
325  * \param ctx       CSR context to free
326  */
327 void mbedtls_x509write_csr_free(mbedtls_x509write_csr *ctx);
328 
329 /**
330  * \brief           Write a CSR (Certificate Signing Request) to a
331  *                  DER structure
332  *                  Note: data is written at the end of the buffer! Use the
333  *                        return value to determine where you should start
334  *                        using the buffer
335  *
336  * \param ctx       CSR to write away
337  * \param buf       buffer to write to
338  * \param size      size of the buffer
339  *
340  * \return          length of data written if successful, or a specific
341  *                  error code
342  *
343  */
344 int mbedtls_x509write_csr_der(mbedtls_x509write_csr *ctx, unsigned char *buf, size_t size);
345 
346 #if defined(MBEDTLS_PEM_WRITE_C)
347 /**
348  * \brief           Write a CSR (Certificate Signing Request) to a
349  *                  PEM string
350  *
351  * \param ctx       CSR to write away
352  * \param buf       buffer to write to
353  * \param size      size of the buffer
354  *
355  * \return          0 if successful, or a specific error code
356  *
357  */
358 int mbedtls_x509write_csr_pem(mbedtls_x509write_csr *ctx, unsigned char *buf, size_t size);
359 #endif /* MBEDTLS_PEM_WRITE_C */
360 #endif /* MBEDTLS_X509_CSR_WRITE_C */
361 
362 /** \} addtogroup x509_module */
363 
364 #ifdef __cplusplus
365 }
366 #endif
367 
368 #endif /* mbedtls_x509_csr.h */
369