1 /**
2 * \file pem.h
3 *
4 * \brief Privacy Enhanced Mail (PEM) decoding
5 */
6 /*
7 * Copyright The Mbed TLS Contributors
8 * SPDX-License-Identifier: Apache-2.0
9 *
10 * Licensed under the Apache License, Version 2.0 (the "License"); you may
11 * not use this file except in compliance with the License.
12 * You may obtain a copy of the License at
13 *
14 * http://www.apache.org/licenses/LICENSE-2.0
15 *
16 * Unless required by applicable law or agreed to in writing, software
17 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
18 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
19 * See the License for the specific language governing permissions and
20 * limitations under the License.
21 */
22 #ifndef MBEDTLS_PEM_H
23 #define MBEDTLS_PEM_H
24 #include "mbedtls/private_access.h"
25
26 #include "mbedtls/build_info.h"
27
28 #include <stddef.h>
29
30 /**
31 * \name PEM Error codes
32 * These error codes are returned in case of errors reading the
33 * PEM data.
34 * \{
35 */
36 /** No PEM header or footer found. */
37 #define MBEDTLS_ERR_PEM_NO_HEADER_FOOTER_PRESENT -0x1080
38 /** PEM string is not as expected. */
39 #define MBEDTLS_ERR_PEM_INVALID_DATA -0x1100
40 /** Failed to allocate memory. */
41 #define MBEDTLS_ERR_PEM_ALLOC_FAILED -0x1180
42 /** RSA IV is not in hex-format. */
43 #define MBEDTLS_ERR_PEM_INVALID_ENC_IV -0x1200
44 /** Unsupported key encryption algorithm. */
45 #define MBEDTLS_ERR_PEM_UNKNOWN_ENC_ALG -0x1280
46 /** Private key password can't be empty. */
47 #define MBEDTLS_ERR_PEM_PASSWORD_REQUIRED -0x1300
48 /** Given private key password does not allow for correct decryption. */
49 #define MBEDTLS_ERR_PEM_PASSWORD_MISMATCH -0x1380
50 /** Unavailable feature, e.g. hashing/encryption combination. */
51 #define MBEDTLS_ERR_PEM_FEATURE_UNAVAILABLE -0x1400
52 /** Bad input parameters to function. */
53 #define MBEDTLS_ERR_PEM_BAD_INPUT_DATA -0x1480
54 /** \} name PEM Error codes */
55
56 #ifdef __cplusplus
57 extern "C" {
58 #endif
59
60 #if defined(MBEDTLS_PEM_PARSE_C)
61 /**
62 * \brief PEM context structure
63 */
64 typedef struct mbedtls_pem_context {
65 unsigned char *MBEDTLS_PRIVATE(buf); /*!< buffer for decoded data */
66 size_t MBEDTLS_PRIVATE(buflen); /*!< length of the buffer */
67 unsigned char *MBEDTLS_PRIVATE(info); /*!< buffer for extra header information */
68 }
69 mbedtls_pem_context;
70
71 /**
72 * \brief PEM context setup
73 *
74 * \param ctx context to be initialized
75 */
76 void mbedtls_pem_init(mbedtls_pem_context *ctx);
77
78 /**
79 * \brief Read a buffer for PEM information and store the resulting
80 * data into the specified context buffers.
81 *
82 * \param ctx context to use
83 * \param header header string to seek and expect
84 * \param footer footer string to seek and expect
85 * \param data source data to look in (must be nul-terminated)
86 * \param pwd password for decryption (can be NULL)
87 * \param pwdlen length of password
88 * \param use_len destination for total length used (set after header is
89 * correctly read, so unless you get
90 * MBEDTLS_ERR_PEM_BAD_INPUT_DATA or
91 * MBEDTLS_ERR_PEM_NO_HEADER_FOOTER_PRESENT, use_len is
92 * the length to skip)
93 *
94 * \note Attempts to check password correctness by verifying if
95 * the decrypted text starts with an ASN.1 sequence of
96 * appropriate length
97 *
98 * \note \c mbedtls_pem_free must be called on PEM context before
99 * the PEM context can be reused in another call to
100 * \c mbedtls_pem_read_buffer
101 *
102 * \return 0 on success, or a specific PEM error code
103 */
104 int mbedtls_pem_read_buffer(mbedtls_pem_context *ctx, const char *header, const char *footer,
105 const unsigned char *data,
106 const unsigned char *pwd,
107 size_t pwdlen, size_t *use_len);
108
109 /**
110 * \brief Get the pointer to the decoded binary data in a PEM context.
111 *
112 * \param ctx PEM context to access.
113 * \param buflen On success, this will contain the length of the binary data.
114 * This must be a valid (non-null) pointer.
115 *
116 * \return A pointer to the decoded binary data.
117 *
118 * \note The returned pointer remains valid only until \p ctx is
119 modified or freed.
120 */
mbedtls_pem_get_buffer(mbedtls_pem_context * ctx,size_t * buflen)121 static inline const unsigned char *mbedtls_pem_get_buffer(mbedtls_pem_context *ctx, size_t *buflen)
122 {
123 *buflen = ctx->MBEDTLS_PRIVATE(buflen);
124 return ctx->MBEDTLS_PRIVATE(buf);
125 }
126
127
128 /**
129 * \brief PEM context memory freeing
130 *
131 * \param ctx context to be freed
132 */
133 void mbedtls_pem_free(mbedtls_pem_context *ctx);
134 #endif /* MBEDTLS_PEM_PARSE_C */
135
136 #if defined(MBEDTLS_PEM_WRITE_C)
137 /**
138 * \brief Write a buffer of PEM information from a DER encoded
139 * buffer.
140 *
141 * \param header The header string to write.
142 * \param footer The footer string to write.
143 * \param der_data The DER data to encode.
144 * \param der_len The length of the DER data \p der_data in Bytes.
145 * \param buf The buffer to write to.
146 * \param buf_len The length of the output buffer \p buf in Bytes.
147 * \param olen The address at which to store the total length written
148 * or required (if \p buf_len is not enough).
149 *
150 * \note You may pass \c NULL for \p buf and \c 0 for \p buf_len
151 * to request the length of the resulting PEM buffer in
152 * `*olen`.
153 *
154 * \note This function may be called with overlapping \p der_data
155 * and \p buf buffers.
156 *
157 * \return \c 0 on success.
158 * \return #MBEDTLS_ERR_BASE64_BUFFER_TOO_SMALL if \p buf isn't large
159 * enough to hold the PEM buffer. In this case, `*olen` holds
160 * the required minimum size of \p buf.
161 * \return Another PEM or BASE64 error code on other kinds of failure.
162 */
163 int mbedtls_pem_write_buffer(const char *header, const char *footer,
164 const unsigned char *der_data, size_t der_len,
165 unsigned char *buf, size_t buf_len, size_t *olen);
166 #endif /* MBEDTLS_PEM_WRITE_C */
167
168 #ifdef __cplusplus
169 }
170 #endif
171
172 #endif /* pem.h */
173