Debug: more info for string-expansion troubles
[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
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29#define PDKIM_DEFAULT_SIGN_HEADERS "From:Sender:Reply-To:Subject:Date:"\
30 "Message-ID:To:Cc:MIME-Version:Content-Type:"\
31 "Content-Transfer-Encoding:Content-ID:"\
32 "Content-Description:Resent-Date:Resent-From:"\
33 "Resent-Sender:Resent-To:Resent-Cc:"\
34 "Resent-Message-ID:In-Reply-To:References:"\
35 "List-Id:List-Help:List-Unsubscribe:"\
36 "List-Subscribe:List-Post:List-Owner:List-Archive"
37
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38/* -------------------------------------------------------------------------- */
39/* Length of the preallocated buffer for the "answer" from the dns/txt
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40 callback function. This should match the maximum RDLENGTH from DNS. */
41#define PDKIM_DNS_TXT_MAX_RECLEN (1 << 16)
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42
43/* -------------------------------------------------------------------------- */
44/* Function success / error codes */
45#define PDKIM_OK 0
46#define PDKIM_FAIL -1
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47#define PDKIM_ERR_RSA_PRIVKEY -101
48#define PDKIM_ERR_RSA_SIGNING -102
49#define PDKIM_ERR_LONG_LINE -103
50#define PDKIM_ERR_BUFFER_TOO_SMALL -104
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51#define PDKIM_SIGN_PRIVKEY_WRAP -105
52#define PDKIM_SIGN_PRIVKEY_B64D -106
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53
54/* -------------------------------------------------------------------------- */
55/* Main/Extended verification status */
56#define PDKIM_VERIFY_NONE 0
57#define PDKIM_VERIFY_INVALID 1
58#define PDKIM_VERIFY_FAIL 2
59#define PDKIM_VERIFY_PASS 3
60
07eeb4df 61#define PDKIM_VERIFY_FAIL_BODY 1
62#define PDKIM_VERIFY_FAIL_MESSAGE 2
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63#define PDKIM_VERIFY_FAIL_SIG_ALGO_MISMATCH 3
64#define PDKIM_VERIFY_INVALID_PUBKEY_UNAVAILABLE 4
65#define PDKIM_VERIFY_INVALID_BUFFER_SIZE 5
66#define PDKIM_VERIFY_INVALID_PUBKEY_DNSRECORD 6
67#define PDKIM_VERIFY_INVALID_PUBKEY_IMPORT 7
68#define PDKIM_VERIFY_INVALID_SIGNATURE_ERROR 8
69#define PDKIM_VERIFY_INVALID_DKIM_VERSION 9
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70
71/* -------------------------------------------------------------------------- */
72/* Some parameter values */
73#define PDKIM_QUERYMETHOD_DNS_TXT 0
74
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75#define PDKIM_CANON_SIMPLE 0
76#define PDKIM_CANON_RELAXED 1
77
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78/* -------------------------------------------------------------------------- */
79/* Some required forward declarations, please ignore */
80typedef struct pdkim_stringlist pdkim_stringlist;
81typedef struct pdkim_str pdkim_str;
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82typedef struct sha1_context sha1_context;
83typedef struct sha2_context sha2_context;
84#define HAVE_SHA1_CONTEXT
85#define HAVE_SHA2_CONTEXT
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86
87/* -------------------------------------------------------------------------- */
88/* Some concessions towards Redmond */
89#ifdef WINDOWS
90#define snprintf _snprintf
91#define strcasecmp _stricmp
92#define strncasecmp _strnicmp
93#define DLLEXPORT __declspec(dllexport)
94#else
95#define DLLEXPORT
96#endif
97
98
99/* -------------------------------------------------------------------------- */
100/* Public key as (usually) fetched from DNS */
101typedef struct pdkim_pubkey {
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102 const uschar * version; /* v= */
103 const uschar *granularity; /* g= */
80a47a2c 104
35cf75e9 105 const uschar * hashes; /* h= */
135e9496 106#ifdef notdef
e2e3255a 107 uschar *keytype; /* k= */
e21a4d00 108#endif
35cf75e9 109 const uschar *srvtype; /* s= */
e2e3255a 110 uschar *notes; /* n= */
80a47a2c 111
2592e6c0 112 blob key; /* p= */
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113 int testing; /* t=y */
114 int no_subdomaining; /* t=s */
115} pdkim_pubkey;
116
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117/* -------------------------------------------------------------------------- */
118/* Body-hash to be calculated */
119typedef struct pdkim_bodyhash {
120 struct pdkim_bodyhash * next;
121 int hashtype;
122 int canon_method;
123 long bodylength;
124
125 hctx body_hash_ctx;
126 unsigned long signed_body_bytes; /* done so far */
127 int num_buffered_blanklines;
128
129 blob bh; /* completed hash */
130} pdkim_bodyhash;
131
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132/* -------------------------------------------------------------------------- */
133/* Signature as it appears in a DKIM-Signature header */
134typedef struct pdkim_signature {
9e70917d 135 struct pdkim_signature * next;
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136
137 /* Bits stored in a DKIM signature header --------------------------- */
138
139 /* (v=) The version, as an integer. Currently, always "1" */
140 int version;
141
cf1cce5e 142 int keytype; /* pdkim_keytypes index */
d73e45df 143 int hashtype; /* pdkim_hashes index */
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144
145 /* (c=x/) Header canonicalization method. Either PDKIM_CANON_SIMPLE
146 or PDKIM_CANON_RELAXED */
147 int canon_headers;
148
149 /* (c=/x) Body canonicalization method. Either PDKIM_CANON_SIMPLE
150 or PDKIM_CANON_RELAXED */
151 int canon_body;
152
153 /* (q=) Query Method. Currently, only PDKIM_QUERYMETHOD_DNS_TXT
154 is specified */
155 int querymethod;
156
157 /* (s=) The selector string as given in the signature */
e2e3255a 158 uschar *selector;
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159
160 /* (d=) The domain as given in the signature */
e2e3255a 161 uschar *domain;
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162
163 /* (i=) The identity as given in the signature */
e2e3255a 164 uschar *identity;
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165
166 /* (t=) Timestamp of signature creation */
167 unsigned long created;
168
169 /* (x=) Timestamp of expiry of signature */
170 unsigned long expires;
171
172 /* (l=) Amount of hashed body bytes (after canonicalization). Default
173 is -1. Note: a value of 0 means that the body is unsigned! */
174 long bodylength;
175
176 /* (h=) Colon-separated list of header names that are included in the
177 signature */
2592e6c0 178 uschar *headernames;
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179
180 /* (z=) */
e2e3255a 181 uschar *copiedheaders;
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182
183 /* (b=) Raw signature data, along with its length in bytes */
dcd03763 184 blob sighash;
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185
186 /* (bh=) Raw body hash data, along with its length in bytes */
2592e6c0 187 blob bodyhash;
80a47a2c 188
9e70917d 189 /* Folded DKIM-Signature: header. Signing only, NULL for verifying.
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190 Ready for insertion into the message. Note: Folded using CRLFTB,
191 but final line terminator is NOT included. Note2: This buffer is
192 free()d when you call pdkim_free_ctx(). */
e2e3255a 193 uschar *signature_header;
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194
195 /* The main verification status. Verification only. One of:
196
197 PDKIM_VERIFY_NONE Verification was not attempted. This status
198 should not appear.
199
200 PDKIM_VERIFY_INVALID There was an error while trying to verify
201 the signature. A more precise description
202 is available in verify_ext_status.
203
204 PDKIM_VERIFY_FAIL Verification failed because either the body
205 hash did not match, or the signature verification
206 failed. This means the message was modified.
207 Check verify_ext_status for the exact reason.
208
209 PDKIM_VERIFY_PASS Verification succeeded.
210 */
211 int verify_status;
212
213 /* Extended verification status. Verification only. Depending on the value
214 of verify_status, it can contain:
215
216 For verify_status == PDKIM_VERIFY_INVALID:
217
218 PDKIM_VERIFY_INVALID_PUBKEY_UNAVAILABLE
219 Unable to retrieve a public key container.
220
221 PDKIM_VERIFY_INVALID_BUFFER_SIZE
222 Either the DNS name constructed to retrieve the public key record
223 does not fit into PDKIM_DNS_TXT_MAX_NAMELEN bytes, or the retrieved
224 record is longer than PDKIM_DNS_TXT_MAX_RECLEN bytes.
225
226 PDKIM_VERIFY_INVALID_PUBKEY_PARSING
227 (Syntax) error while parsing the retrieved public key record.
228
229
230 For verify_status == PDKIM_VERIFY_FAIL:
231
232 PDKIM_VERIFY_FAIL_BODY
233 The calculated body hash does not match the advertised body hash
234 from the bh= tag of the signature.
235
236 PDKIM_VERIFY_FAIL_MESSAGE
237 RSA verification of the signature (b= tag) failed.
238 */
239 int verify_ext_status;
240
241 /* Pointer to a public key record that was used to verify the signature.
242 See pdkim_pubkey declaration above for more information.
243 Caution: is NULL if signing or if no record was retrieved. */
244 pdkim_pubkey *pubkey;
245
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246 /* Properties below this point are used internally only ------------- */
247
248 /* Per-signature helper variables ----------------------------------- */
cf1cce5e 249 pdkim_bodyhash *calc_body_hash; /* hash to be / being calculated */
2592e6c0 250
cf1cce5e 251 pdkim_stringlist *headers; /* Raw headers included in the sig */
9e70917d 252
80a47a2c 253 /* Signing specific ------------------------------------------------- */
d73e45df 254 uschar * privkey; /* Private key */
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255 uschar * sign_headers; /* To-be-signed header names */
256 uschar * rawsig_no_b_val; /* Original signature header w/o b= tag value. */
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257} pdkim_signature;
258
259
260/* -------------------------------------------------------------------------- */
261/* Context to keep state between all operations. */
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262typedef struct pdkim_ctx {
263
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264#define PDKIM_MODE_SIGN BIT(0) /* if unset, mode==verify */
265#define PDKIM_DOT_TERM BIT(1) /* dot termination and unstuffing */
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266#define PDKIM_SEEN_CR BIT(2)
267#define PDKIM_SEEN_LF BIT(3)
e983e85a 268#define PDKIM_PAST_HDRS BIT(4)
b895f4b2 269#define PDKIM_SEEN_EOD BIT(5)
e983e85a 270 unsigned flags;
80a47a2c 271
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272 /* One (signing) or several chained (verification) signatures */
273 pdkim_signature *sig;
274
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275 /* One (signing) or several chained (verification) bodyhashes */
276 pdkim_bodyhash *bodyhash;
277
80a47a2c 278 /* Callback for dns/txt query method (verification only) */
1eedc10f 279 uschar * (*dns_txt_callback)(char *);
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280
281 /* Coder's little helpers */
acec9514 282 gstring *cur_header;
7845dbb3 283 uschar *linebuf;
80a47a2c 284 int linebuf_offset;
80a47a2c 285 int num_headers;
37f8b554 286 pdkim_stringlist *headers; /* Raw headers for verification */
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287} pdkim_ctx;
288
289
290/* -------------------------------------------------------------------------- */
291/* API functions. Please see the sample code in sample/test_sign.c and
292 sample/test_verify.c for documentation.
293*/
294
295#ifdef __cplusplus
296extern "C" {
297#endif
298
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299void pdkim_init (void);
300
1eedc10f 301void pdkim_init_context (pdkim_ctx *, BOOL, uschar * (*)(char *));
9e70917d 302
80a47a2c 303DLLEXPORT
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304pdkim_signature *pdkim_init_sign (pdkim_ctx *,
305 uschar *, uschar *, uschar *, uschar *,
306 const uschar **);
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307
308DLLEXPORT
1eedc10f 309pdkim_ctx *pdkim_init_verify (uschar * (*)(char *), BOOL);
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310
311DLLEXPORT
9e70917d 312void pdkim_set_optional (pdkim_signature *, char *, char *,int, int,
f444c2c7 313 long,
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314 unsigned long,
315 unsigned long);
316
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317pdkim_bodyhash *pdkim_set_bodyhash(pdkim_ctx *, pdkim_signature *);
318
80a47a2c 319DLLEXPORT
ef698bf6 320int pdkim_feed (pdkim_ctx *, uschar *, int);
80a47a2c 321DLLEXPORT
b9df1829 322int pdkim_feed_finish (pdkim_ctx *, pdkim_signature **, const uschar **);
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323
324DLLEXPORT
325void pdkim_free_ctx (pdkim_ctx *);
326
f7302073 327
b9df1829 328const uschar * pdkim_errstr(int);
f7302073 329
9e70917d 330uschar * dkim_sig_to_a_tag(const pdkim_signature * sig);
d73e45df 331
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332#ifdef __cplusplus
333}
334#endif
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335
336#endif