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 OR GPL-2.0-or-later
9 */
10 #ifndef MBEDTLS_PEM_H
11 #define MBEDTLS_PEM_H
12 #include "mbedtls/private_access.h"
13
14 #include "mbedtls/build_info.h"
15
16 #include <stddef.h>
17
18 /**
19 * \name PEM Error codes
20 * These error codes are returned in case of errors reading the
21 * PEM data.
22 * \{
23 */
24 /** No PEM header or footer found. */
25 #define MBEDTLS_ERR_PEM_NO_HEADER_FOOTER_PRESENT -0x1080
26 /** PEM string is not as expected. */
27 #define MBEDTLS_ERR_PEM_INVALID_DATA -0x1100
28 /** Failed to allocate memory. */
29 #define MBEDTLS_ERR_PEM_ALLOC_FAILED -0x1180
30 /** RSA IV is not in hex-format. */
31 #define MBEDTLS_ERR_PEM_INVALID_ENC_IV -0x1200
32 /** Unsupported key encryption algorithm. */
33 #define MBEDTLS_ERR_PEM_UNKNOWN_ENC_ALG -0x1280
34 /** Private key password can't be empty. */
35 #define MBEDTLS_ERR_PEM_PASSWORD_REQUIRED -0x1300
36 /** Given private key password does not allow for correct decryption. */
37 #define MBEDTLS_ERR_PEM_PASSWORD_MISMATCH -0x1380
38 /** Unavailable feature, e.g. hashing/encryption combination. */
39 #define MBEDTLS_ERR_PEM_FEATURE_UNAVAILABLE -0x1400
40 /** Bad input parameters to function. */
41 #define MBEDTLS_ERR_PEM_BAD_INPUT_DATA -0x1480
42 /** \} name PEM Error codes */
43
44 #ifdef __cplusplus
45 extern "C" {
46 #endif
47
48 #if defined(MBEDTLS_PEM_PARSE_C)
49 /**
50 * \brief PEM context structure
51 */
52 typedef struct mbedtls_pem_context {
53 unsigned char *MBEDTLS_PRIVATE(buf); /*!< buffer for decoded data */
54 size_t MBEDTLS_PRIVATE(buflen); /*!< length of the buffer */
55 unsigned char *MBEDTLS_PRIVATE(info); /*!< buffer for extra header information */
56 }
57 mbedtls_pem_context;
58
59 /**
60 * \brief PEM context setup
61 *
62 * \param ctx context to be initialized
63 */
64 void mbedtls_pem_init(mbedtls_pem_context *ctx);
65
66 /**
67 * \brief Read a buffer for PEM information and store the resulting
68 * data into the specified context buffers.
69 *
70 * \param ctx context to use
71 * \param header header string to seek and expect
72 * \param footer footer string to seek and expect
73 * \param data source data to look in (must be nul-terminated)
74 * \param pwd password for decryption (can be NULL)
75 * \param pwdlen length of password
76 * \param use_len destination for total length used from data buffer. It is
77 * set after header is correctly read, so unless you get
78 * MBEDTLS_ERR_PEM_BAD_INPUT_DATA or
79 * MBEDTLS_ERR_PEM_NO_HEADER_FOOTER_PRESENT, use_len is
80 * the length to skip.
81 *
82 * \note Attempts to check password correctness by verifying if
83 * the decrypted text starts with an ASN.1 sequence of
84 * appropriate length
85 *
86 * \note \c mbedtls_pem_free must be called on PEM context before
87 * the PEM context can be reused in another call to
88 * \c mbedtls_pem_read_buffer
89 *
90 * \return 0 on success, or a specific PEM error code
91 */
92 int mbedtls_pem_read_buffer(mbedtls_pem_context *ctx, const char *header, const char *footer,
93 const unsigned char *data,
94 const unsigned char *pwd,
95 size_t pwdlen, size_t *use_len);
96
97 /**
98 * \brief Get the pointer to the decoded binary data in a PEM context.
99 *
100 * \param ctx PEM context to access.
101 * \param buflen On success, this will contain the length of the binary data.
102 * This must be a valid (non-null) pointer.
103 *
104 * \return A pointer to the decoded binary data.
105 *
106 * \note The returned pointer remains valid only until \p ctx is
107 modified or freed.
108 */
mbedtls_pem_get_buffer(mbedtls_pem_context * ctx,size_t * buflen)109 static inline const unsigned char *mbedtls_pem_get_buffer(mbedtls_pem_context *ctx, size_t *buflen)
110 {
111 *buflen = ctx->MBEDTLS_PRIVATE(buflen);
112 return ctx->MBEDTLS_PRIVATE(buf);
113 }
114
115
116 /**
117 * \brief PEM context memory freeing
118 *
119 * \param ctx context to be freed
120 */
121 void mbedtls_pem_free(mbedtls_pem_context *ctx);
122 #endif /* MBEDTLS_PEM_PARSE_C */
123
124 #if defined(MBEDTLS_PEM_WRITE_C)
125 /**
126 * \brief Write a buffer of PEM information from a DER encoded
127 * buffer.
128 *
129 * \param header The header string to write.
130 * \param footer The footer string to write.
131 * \param der_data The DER data to encode.
132 * \param der_len The length of the DER data \p der_data in Bytes.
133 * \param buf The buffer to write to.
134 * \param buf_len The length of the output buffer \p buf in Bytes.
135 * \param olen The address at which to store the total length written
136 * or required (if \p buf_len is not enough).
137 *
138 * \note You may pass \c NULL for \p buf and \c 0 for \p buf_len
139 * to request the length of the resulting PEM buffer in
140 * `*olen`.
141 *
142 * \note This function may be called with overlapping \p der_data
143 * and \p buf buffers.
144 *
145 * \return \c 0 on success.
146 * \return #MBEDTLS_ERR_BASE64_BUFFER_TOO_SMALL if \p buf isn't large
147 * enough to hold the PEM buffer. In this case, `*olen` holds
148 * the required minimum size of \p buf.
149 * \return Another PEM or BASE64 error code on other kinds of failure.
150 */
151 int mbedtls_pem_write_buffer(const char *header, const char *footer,
152 const unsigned char *der_data, size_t der_len,
153 unsigned char *buf, size_t buf_len, size_t *olen);
154 #endif /* MBEDTLS_PEM_WRITE_C */
155
156 #ifdef __cplusplus
157 }
158 #endif
159
160 #endif /* pem.h */
161
