Logging: millisecond time on 'no MAIL' lines. Bug 2102
[exim.git] / src / src / pdkim / pdkim.h
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1/*
2 * PDKIM - a RFC4871 (DKIM) implementation
3 *
c4ceed07 4 * Copyright (C) 2009 - 2012 Tom Kistner <tom@duncanthrax.net>
d4e5e70b 5 * Copyright (c) 2016 - 2017 Jeremy Harris
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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 */
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23#ifndef PDKIM_H
24#define PDKIM_H
25
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26#include "../blob.h"
27#include "../hash.h"
80a47a2c 28
80a47a2c 29/* -------------------------------------------------------------------------- */
80a47a2c 30/* Length of the preallocated buffer for the "answer" from the dns/txt
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31 callback function. This should match the maximum RDLENGTH from DNS. */
32#define PDKIM_DNS_TXT_MAX_RECLEN (1 << 16)
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33
34/* -------------------------------------------------------------------------- */
35/* Function success / error codes */
36#define PDKIM_OK 0
37#define PDKIM_FAIL -1
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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
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42#define PDKIM_SIGN_PRIVKEY_WRAP -105
43#define PDKIM_SIGN_PRIVKEY_B64D -106
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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
07eeb4df 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
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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 */
78typedef struct pdkim_stringlist pdkim_stringlist;
79typedef struct pdkim_str pdkim_str;
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80typedef struct sha1_context sha1_context;
81typedef struct sha2_context sha2_context;
82#define HAVE_SHA1_CONTEXT
83#define HAVE_SHA2_CONTEXT
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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 */
99typedef struct pdkim_pubkey {
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100 uschar *version; /* v= */
101 uschar *granularity; /* g= */
80a47a2c 102
e21a4d00 103#ifdef notdef
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104 uschar *hashes; /* h= */
105 uschar *keytype; /* k= */
e21a4d00 106#endif
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107 uschar *srvtype; /* s= */
108 uschar *notes; /* n= */
80a47a2c 109
2592e6c0 110 blob key; /* p= */
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111 int testing; /* t=y */
112 int no_subdomaining; /* t=s */
113} pdkim_pubkey;
114
115/* -------------------------------------------------------------------------- */
116/* Signature as it appears in a DKIM-Signature header */
117typedef struct pdkim_signature {
118
119 /* Bits stored in a DKIM signature header --------------------------- */
120
121 /* (v=) The version, as an integer. Currently, always "1" */
122 int version;
123
124 /* (a=) The signature algorithm. Either PDKIM_ALGO_RSA_SHA256
125 or PDKIM_ALGO_RSA_SHA1 */
126 int algo;
127
128 /* (c=x/) Header canonicalization method. Either PDKIM_CANON_SIMPLE
129 or PDKIM_CANON_RELAXED */
130 int canon_headers;
131
132 /* (c=/x) Body canonicalization method. Either PDKIM_CANON_SIMPLE
133 or PDKIM_CANON_RELAXED */
134 int canon_body;
135
136 /* (q=) Query Method. Currently, only PDKIM_QUERYMETHOD_DNS_TXT
137 is specified */
138 int querymethod;
139
140 /* (s=) The selector string as given in the signature */
e2e3255a 141 uschar *selector;
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142
143 /* (d=) The domain as given in the signature */
e2e3255a 144 uschar *domain;
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145
146 /* (i=) The identity as given in the signature */
e2e3255a 147 uschar *identity;
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148
149 /* (t=) Timestamp of signature creation */
150 unsigned long created;
151
152 /* (x=) Timestamp of expiry of signature */
153 unsigned long expires;
154
155 /* (l=) Amount of hashed body bytes (after canonicalization). Default
156 is -1. Note: a value of 0 means that the body is unsigned! */
157 long bodylength;
158
159 /* (h=) Colon-separated list of header names that are included in the
160 signature */
2592e6c0 161 uschar *headernames;
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162
163 /* (z=) */
e2e3255a 164 uschar *copiedheaders;
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165
166 /* (b=) Raw signature data, along with its length in bytes */
dcd03763 167 blob sighash;
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168
169 /* (bh=) Raw body hash data, along with its length in bytes */
2592e6c0 170 blob bodyhash;
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171
172 /* Folded DKIM-Signature: header. Singing only, NULL for verifying.
173 Ready for insertion into the message. Note: Folded using CRLFTB,
174 but final line terminator is NOT included. Note2: This buffer is
175 free()d when you call pdkim_free_ctx(). */
e2e3255a 176 uschar *signature_header;
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177
178 /* The main verification status. Verification only. One of:
179
180 PDKIM_VERIFY_NONE Verification was not attempted. This status
181 should not appear.
182
183 PDKIM_VERIFY_INVALID There was an error while trying to verify
184 the signature. A more precise description
185 is available in verify_ext_status.
186
187 PDKIM_VERIFY_FAIL Verification failed because either the body
188 hash did not match, or the signature verification
189 failed. This means the message was modified.
190 Check verify_ext_status for the exact reason.
191
192 PDKIM_VERIFY_PASS Verification succeeded.
193 */
194 int verify_status;
195
196 /* Extended verification status. Verification only. Depending on the value
197 of verify_status, it can contain:
198
199 For verify_status == PDKIM_VERIFY_INVALID:
200
201 PDKIM_VERIFY_INVALID_PUBKEY_UNAVAILABLE
202 Unable to retrieve a public key container.
203
204 PDKIM_VERIFY_INVALID_BUFFER_SIZE
205 Either the DNS name constructed to retrieve the public key record
206 does not fit into PDKIM_DNS_TXT_MAX_NAMELEN bytes, or the retrieved
207 record is longer than PDKIM_DNS_TXT_MAX_RECLEN bytes.
208
209 PDKIM_VERIFY_INVALID_PUBKEY_PARSING
210 (Syntax) error while parsing the retrieved public key record.
211
212
213 For verify_status == PDKIM_VERIFY_FAIL:
214
215 PDKIM_VERIFY_FAIL_BODY
216 The calculated body hash does not match the advertised body hash
217 from the bh= tag of the signature.
218
219 PDKIM_VERIFY_FAIL_MESSAGE
220 RSA verification of the signature (b= tag) failed.
221 */
222 int verify_ext_status;
223
224 /* Pointer to a public key record that was used to verify the signature.
225 See pdkim_pubkey declaration above for more information.
226 Caution: is NULL if signing or if no record was retrieved. */
227 pdkim_pubkey *pubkey;
228
229 /* Pointer to the next pdkim_signature signature. NULL if signing or if
230 this is the last signature. */
231 void *next;
232
233 /* Properties below this point are used internally only ------------- */
234
235 /* Per-signature helper variables ----------------------------------- */
dcd03763 236 hctx body_hash_ctx;
2592e6c0 237
80a47a2c 238 unsigned long signed_body_bytes; /* How many body bytes we hashed */
cb224393 239 pdkim_stringlist *headers; /* Raw headers included in the sig */
80a47a2c 240 /* Signing specific ------------------------------------------------- */
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241 uschar * rsa_privkey; /* Private RSA key */
242 uschar * sign_headers; /* To-be-signed header names */
243 uschar * rawsig_no_b_val; /* Original signature header w/o b= tag value. */
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244} pdkim_signature;
245
246
247/* -------------------------------------------------------------------------- */
248/* Context to keep state between all operations. */
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249typedef struct pdkim_ctx {
250
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251#define PDKIM_MODE_SIGN BIT(0) /* if unset, mode==verify */
252#define PDKIM_DOT_TERM BIT(1) /* dot termination and unstuffing */
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253#define PDKIM_SEEN_CR BIT(2)
254#define PDKIM_SEEN_LF BIT(3)
e983e85a 255#define PDKIM_PAST_HDRS BIT(4)
b895f4b2 256#define PDKIM_SEEN_EOD BIT(5)
e983e85a 257 unsigned flags;
80a47a2c 258
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259 /* One (signing) or several chained (verification) signatures */
260 pdkim_signature *sig;
261
262 /* Callback for dns/txt query method (verification only) */
263 int(*dns_txt_callback)(char *, char *);
264
265 /* Coder's little helpers */
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266 uschar *cur_header;
267 int cur_header_size;
268 int cur_header_len;
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269 char *linebuf;
270 int linebuf_offset;
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271 int num_buffered_crlf;
272 int num_headers;
37f8b554 273 pdkim_stringlist *headers; /* Raw headers for verification */
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274} pdkim_ctx;
275
276
277/* -------------------------------------------------------------------------- */
278/* API functions. Please see the sample code in sample/test_sign.c and
279 sample/test_verify.c for documentation.
280*/
281
282#ifdef __cplusplus
283extern "C" {
284#endif
285
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286void pdkim_init (void);
287
80a47a2c 288DLLEXPORT
cd1a5fe0 289pdkim_ctx *pdkim_init_sign (char *, char *, char *, int,
b9df1829 290 BOOL, int(*)(char *, char *), const uschar **);
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291
292DLLEXPORT
e983e85a 293pdkim_ctx *pdkim_init_verify (int(*)(char *, char *), BOOL);
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294
295DLLEXPORT
296int pdkim_set_optional (pdkim_ctx *, char *, char *,int, int,
f444c2c7 297 long,
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298 unsigned long,
299 unsigned long);
300
301DLLEXPORT
ef698bf6 302int pdkim_feed (pdkim_ctx *, uschar *, int);
80a47a2c 303DLLEXPORT
b9df1829 304int pdkim_feed_finish (pdkim_ctx *, pdkim_signature **, const uschar **);
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305
306DLLEXPORT
307void pdkim_free_ctx (pdkim_ctx *);
308
f7302073 309
b9df1829 310const uschar * pdkim_errstr(int);
f7302073 311
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312#ifdef __cplusplus
313}
314#endif
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315
316#endif