OpenSSL: add detail to certname verify fail log line
[exim.git] / src / src / pdkim / pdkim.h
1 /*
2 * PDKIM - a RFC4871 (DKIM) implementation
3 *
4 * Copyright (C) 2009 - 2012 Tom Kistner <tom@duncanthrax.net>
5 * Copyright (c) Jeremy Harris 2016
6 *
7 * http://duncanthrax.net/pdkim/
8 *
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License as published by
11 * the Free Software Foundation; either version 2 of the License, or
12 * (at your option) any later version.
13 *
14 * This program is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 * GNU General Public License for more details.
18 *
19 * You should have received a copy of the GNU General Public License along
20 * with this program; if not, write to the Free Software Foundation, Inc.,
21 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
22 */
23 #ifndef PDKIM_H
24 #define PDKIM_H
25
26 #include "../blob.h"
27 #include "../hash.h"
28
29 /* -------------------------------------------------------------------------- */
30 /* Length of the preallocated buffer for the "answer" from the dns/txt
31 callback function. This should match the maximum RDLENGTH from DNS. */
32 #define PDKIM_DNS_TXT_MAX_RECLEN (1 << 16)
33
34 /* -------------------------------------------------------------------------- */
35 /* Function success / error codes */
36 #define PDKIM_OK 0
37 #define PDKIM_FAIL -1
38 #define PDKIM_ERR_RSA_PRIVKEY -101
39 #define PDKIM_ERR_RSA_SIGNING -102
40 #define PDKIM_ERR_LONG_LINE -103
41 #define PDKIM_ERR_BUFFER_TOO_SMALL -104
42 #define PDKIM_SIGN_PRIVKEY_WRAP -105
43 #define PDKIM_SIGN_PRIVKEY_B64D -106
44
45 /* -------------------------------------------------------------------------- */
46 /* Main/Extended verification status */
47 #define PDKIM_VERIFY_NONE 0
48 #define PDKIM_VERIFY_INVALID 1
49 #define PDKIM_VERIFY_FAIL 2
50 #define PDKIM_VERIFY_PASS 3
51
52 #define PDKIM_VERIFY_FAIL_BODY 1
53 #define PDKIM_VERIFY_FAIL_MESSAGE 2
54 #define PDKIM_VERIFY_INVALID_PUBKEY_UNAVAILABLE 3
55 #define PDKIM_VERIFY_INVALID_BUFFER_SIZE 4
56 #define PDKIM_VERIFY_INVALID_PUBKEY_DNSRECORD 5
57 #define PDKIM_VERIFY_INVALID_PUBKEY_IMPORT 6
58 #define PDKIM_VERIFY_INVALID_SIGNATURE_ERROR 7
59 #define PDKIM_VERIFY_INVALID_DKIM_VERSION 8
60
61 /* -------------------------------------------------------------------------- */
62 /* Some parameter values */
63 #define PDKIM_QUERYMETHOD_DNS_TXT 0
64
65 #define PDKIM_ALGO_RSA_SHA256 0
66 #define PDKIM_ALGO_RSA_SHA1 1
67
68 #define PDKIM_CANON_SIMPLE 0
69 #define PDKIM_CANON_RELAXED 1
70
71 #define PDKIM_HASH_SHA256 0
72 #define PDKIM_HASH_SHA1 1
73
74 #define PDKIM_KEYTYPE_RSA 0
75
76 /* -------------------------------------------------------------------------- */
77 /* Some required forward declarations, please ignore */
78 typedef struct pdkim_stringlist pdkim_stringlist;
79 typedef struct pdkim_str pdkim_str;
80 typedef struct sha1_context sha1_context;
81 typedef struct sha2_context sha2_context;
82 #define HAVE_SHA1_CONTEXT
83 #define HAVE_SHA2_CONTEXT
84
85 /* -------------------------------------------------------------------------- */
86 /* Some concessions towards Redmond */
87 #ifdef WINDOWS
88 #define snprintf _snprintf
89 #define strcasecmp _stricmp
90 #define strncasecmp _strnicmp
91 #define DLLEXPORT __declspec(dllexport)
92 #else
93 #define DLLEXPORT
94 #endif
95
96
97 /* -------------------------------------------------------------------------- */
98 /* Public key as (usually) fetched from DNS */
99 typedef struct pdkim_pubkey {
100 uschar *version; /* v= */
101 uschar *granularity; /* g= */
102
103 uschar *hashes; /* h= */
104 uschar *keytype; /* k= */
105 uschar *srvtype; /* s= */
106 uschar *notes; /* n= */
107
108 blob key; /* p= */
109
110 int testing; /* t=y */
111 int no_subdomaining; /* t=s */
112 } pdkim_pubkey;
113
114 /* -------------------------------------------------------------------------- */
115 /* Signature as it appears in a DKIM-Signature header */
116 typedef struct pdkim_signature {
117
118 /* Bits stored in a DKIM signature header --------------------------- */
119
120 /* (v=) The version, as an integer. Currently, always "1" */
121 int version;
122
123 /* (a=) The signature algorithm. Either PDKIM_ALGO_RSA_SHA256
124 or PDKIM_ALGO_RSA_SHA1 */
125 int algo;
126
127 /* (c=x/) Header canonicalization method. Either PDKIM_CANON_SIMPLE
128 or PDKIM_CANON_RELAXED */
129 int canon_headers;
130
131 /* (c=/x) Body canonicalization method. Either PDKIM_CANON_SIMPLE
132 or PDKIM_CANON_RELAXED */
133 int canon_body;
134
135 /* (q=) Query Method. Currently, only PDKIM_QUERYMETHOD_DNS_TXT
136 is specified */
137 int querymethod;
138
139 /* (s=) The selector string as given in the signature */
140 uschar *selector;
141
142 /* (d=) The domain as given in the signature */
143 uschar *domain;
144
145 /* (i=) The identity as given in the signature */
146 uschar *identity;
147
148 /* (t=) Timestamp of signature creation */
149 unsigned long created;
150
151 /* (x=) Timestamp of expiry of signature */
152 unsigned long expires;
153
154 /* (l=) Amount of hashed body bytes (after canonicalization). Default
155 is -1. Note: a value of 0 means that the body is unsigned! */
156 long bodylength;
157
158 /* (h=) Colon-separated list of header names that are included in the
159 signature */
160 uschar *headernames;
161
162 /* (z=) */
163 uschar *copiedheaders;
164
165 /* (b=) Raw signature data, along with its length in bytes */
166 blob sigdata;
167
168 /* (bh=) Raw body hash data, along with its length in bytes */
169 blob bodyhash;
170
171 /* Folded DKIM-Signature: header. Singing only, NULL for verifying.
172 Ready for insertion into the message. Note: Folded using CRLFTB,
173 but final line terminator is NOT included. Note2: This buffer is
174 free()d when you call pdkim_free_ctx(). */
175 uschar *signature_header;
176
177 /* The main verification status. Verification only. One of:
178
179 PDKIM_VERIFY_NONE Verification was not attempted. This status
180 should not appear.
181
182 PDKIM_VERIFY_INVALID There was an error while trying to verify
183 the signature. A more precise description
184 is available in verify_ext_status.
185
186 PDKIM_VERIFY_FAIL Verification failed because either the body
187 hash did not match, or the signature verification
188 failed. This means the message was modified.
189 Check verify_ext_status for the exact reason.
190
191 PDKIM_VERIFY_PASS Verification succeeded.
192 */
193 int verify_status;
194
195 /* Extended verification status. Verification only. Depending on the value
196 of verify_status, it can contain:
197
198 For verify_status == PDKIM_VERIFY_INVALID:
199
200 PDKIM_VERIFY_INVALID_PUBKEY_UNAVAILABLE
201 Unable to retrieve a public key container.
202
203 PDKIM_VERIFY_INVALID_BUFFER_SIZE
204 Either the DNS name constructed to retrieve the public key record
205 does not fit into PDKIM_DNS_TXT_MAX_NAMELEN bytes, or the retrieved
206 record is longer than PDKIM_DNS_TXT_MAX_RECLEN bytes.
207
208 PDKIM_VERIFY_INVALID_PUBKEY_PARSING
209 (Syntax) error while parsing the retrieved public key record.
210
211
212 For verify_status == PDKIM_VERIFY_FAIL:
213
214 PDKIM_VERIFY_FAIL_BODY
215 The calculated body hash does not match the advertised body hash
216 from the bh= tag of the signature.
217
218 PDKIM_VERIFY_FAIL_MESSAGE
219 RSA verification of the signature (b= tag) failed.
220 */
221 int verify_ext_status;
222
223 /* Pointer to a public key record that was used to verify the signature.
224 See pdkim_pubkey declaration above for more information.
225 Caution: is NULL if signing or if no record was retrieved. */
226 pdkim_pubkey *pubkey;
227
228 /* Pointer to the next pdkim_signature signature. NULL if signing or if
229 this is the last signature. */
230 void *next;
231
232 /* Properties below this point are used internally only ------------- */
233
234 /* Per-signature helper variables ----------------------------------- */
235 hctx body_hash;
236
237 unsigned long signed_body_bytes; /* How many body bytes we hashed */
238 pdkim_stringlist *headers; /* Raw headers included in the sig */
239 /* Signing specific ------------------------------------------------- */
240 uschar * rsa_privkey; /* Private RSA key */
241 uschar * sign_headers; /* To-be-signed header names */
242 uschar * rawsig_no_b_val; /* Original signature header w/o b= tag value. */
243 } pdkim_signature;
244
245
246 /* -------------------------------------------------------------------------- */
247 /* Context to keep state between all operations. */
248 typedef struct pdkim_ctx {
249
250 #define PDKIM_MODE_SIGN BIT(0) /* if unset, mode==verify */
251 #define PDKIM_DOT_TERM BIT(1) /* dot termination and unstuffing */
252 #define PDKIM_SEEN_LF BIT(2)
253 #define PDKIM_SEEN_EOD BIT(3)
254 #define PDKIM_PAST_HDRS BIT(4)
255 unsigned flags;
256
257 /* One (signing) or several chained (verification) signatures */
258 pdkim_signature *sig;
259
260 /* Callback for dns/txt query method (verification only) */
261 int(*dns_txt_callback)(char *, char *);
262
263 /* Coder's little helpers */
264 uschar *cur_header;
265 int cur_header_size;
266 int cur_header_len;
267 char *linebuf;
268 int linebuf_offset;
269 int num_buffered_crlf;
270 int num_headers;
271 pdkim_stringlist *headers; /* Raw headers for verification */
272 } pdkim_ctx;
273
274
275 /* -------------------------------------------------------------------------- */
276 /* API functions. Please see the sample code in sample/test_sign.c and
277 sample/test_verify.c for documentation.
278 */
279
280 #ifdef __cplusplus
281 extern "C" {
282 #endif
283
284 void pdkim_init (void);
285
286 DLLEXPORT
287 pdkim_ctx *pdkim_init_sign (char *, char *, char *, int, BOOL);
288
289 DLLEXPORT
290 pdkim_ctx *pdkim_init_verify (int(*)(char *, char *), BOOL);
291
292 DLLEXPORT
293 int pdkim_set_optional (pdkim_ctx *, char *, char *,int, int,
294 long,
295 unsigned long,
296 unsigned long);
297
298 DLLEXPORT
299 int pdkim_feed (pdkim_ctx *, char *, int);
300 DLLEXPORT
301 int pdkim_feed_finish (pdkim_ctx *, pdkim_signature **);
302
303 DLLEXPORT
304 void pdkim_free_ctx (pdkim_ctx *);
305
306
307 const char * pdkim_errstr(int);
308
309 #ifdef __cplusplus
310 }
311 #endif
312
313 #endif