Routing: dnslookup and manualroute routers: ipv4_only, ipv4_prefer options. Bug...
[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
80a47a2c 38/* -------------------------------------------------------------------------- */
80a47a2c 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/*XXX change to enums */
79#define PDKIM_HASH_SHA256 1
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80
81#define PDKIM_KEYTYPE_RSA 0
82
83/* -------------------------------------------------------------------------- */
84/* Some required forward declarations, please ignore */
85typedef struct pdkim_stringlist pdkim_stringlist;
86typedef struct pdkim_str pdkim_str;
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87typedef struct sha1_context sha1_context;
88typedef struct sha2_context sha2_context;
89#define HAVE_SHA1_CONTEXT
90#define HAVE_SHA2_CONTEXT
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91
92/* -------------------------------------------------------------------------- */
93/* Some concessions towards Redmond */
94#ifdef WINDOWS
95#define snprintf _snprintf
96#define strcasecmp _stricmp
97#define strncasecmp _strnicmp
98#define DLLEXPORT __declspec(dllexport)
99#else
100#define DLLEXPORT
101#endif
102
103
104/* -------------------------------------------------------------------------- */
105/* Public key as (usually) fetched from DNS */
106typedef struct pdkim_pubkey {
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107 const uschar * version; /* v= */
108 const uschar *granularity; /* g= */
80a47a2c 109
35cf75e9 110 const uschar * hashes; /* h= */
135e9496 111#ifdef notdef
e2e3255a 112 uschar *keytype; /* k= */
e21a4d00 113#endif
35cf75e9 114 const uschar *srvtype; /* s= */
e2e3255a 115 uschar *notes; /* n= */
80a47a2c 116
2592e6c0 117 blob key; /* p= */
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118 int testing; /* t=y */
119 int no_subdomaining; /* t=s */
120} pdkim_pubkey;
121
122/* -------------------------------------------------------------------------- */
123/* Signature as it appears in a DKIM-Signature header */
124typedef struct pdkim_signature {
9e70917d 125 struct pdkim_signature * next;
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126
127 /* Bits stored in a DKIM signature header --------------------------- */
128
129 /* (v=) The version, as an integer. Currently, always "1" */
130 int version;
131
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132 int keytype; /* PDKIM_KEYTYPE_RSA */
133 int hashtype; /* pdkim_hashes index */
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134
135 /* (c=x/) Header canonicalization method. Either PDKIM_CANON_SIMPLE
136 or PDKIM_CANON_RELAXED */
137 int canon_headers;
138
139 /* (c=/x) Body canonicalization method. Either PDKIM_CANON_SIMPLE
140 or PDKIM_CANON_RELAXED */
141 int canon_body;
142
143 /* (q=) Query Method. Currently, only PDKIM_QUERYMETHOD_DNS_TXT
144 is specified */
145 int querymethod;
146
147 /* (s=) The selector string as given in the signature */
e2e3255a 148 uschar *selector;
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149
150 /* (d=) The domain as given in the signature */
e2e3255a 151 uschar *domain;
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152
153 /* (i=) The identity as given in the signature */
e2e3255a 154 uschar *identity;
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155
156 /* (t=) Timestamp of signature creation */
157 unsigned long created;
158
159 /* (x=) Timestamp of expiry of signature */
160 unsigned long expires;
161
162 /* (l=) Amount of hashed body bytes (after canonicalization). Default
163 is -1. Note: a value of 0 means that the body is unsigned! */
164 long bodylength;
165
166 /* (h=) Colon-separated list of header names that are included in the
167 signature */
2592e6c0 168 uschar *headernames;
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169
170 /* (z=) */
e2e3255a 171 uschar *copiedheaders;
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172
173 /* (b=) Raw signature data, along with its length in bytes */
dcd03763 174 blob sighash;
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175
176 /* (bh=) Raw body hash data, along with its length in bytes */
2592e6c0 177 blob bodyhash;
80a47a2c 178
9e70917d 179 /* Folded DKIM-Signature: header. Signing only, NULL for verifying.
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180 Ready for insertion into the message. Note: Folded using CRLFTB,
181 but final line terminator is NOT included. Note2: This buffer is
182 free()d when you call pdkim_free_ctx(). */
e2e3255a 183 uschar *signature_header;
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184
185 /* The main verification status. Verification only. One of:
186
187 PDKIM_VERIFY_NONE Verification was not attempted. This status
188 should not appear.
189
190 PDKIM_VERIFY_INVALID There was an error while trying to verify
191 the signature. A more precise description
192 is available in verify_ext_status.
193
194 PDKIM_VERIFY_FAIL Verification failed because either the body
195 hash did not match, or the signature verification
196 failed. This means the message was modified.
197 Check verify_ext_status for the exact reason.
198
199 PDKIM_VERIFY_PASS Verification succeeded.
200 */
201 int verify_status;
202
203 /* Extended verification status. Verification only. Depending on the value
204 of verify_status, it can contain:
205
206 For verify_status == PDKIM_VERIFY_INVALID:
207
208 PDKIM_VERIFY_INVALID_PUBKEY_UNAVAILABLE
209 Unable to retrieve a public key container.
210
211 PDKIM_VERIFY_INVALID_BUFFER_SIZE
212 Either the DNS name constructed to retrieve the public key record
213 does not fit into PDKIM_DNS_TXT_MAX_NAMELEN bytes, or the retrieved
214 record is longer than PDKIM_DNS_TXT_MAX_RECLEN bytes.
215
216 PDKIM_VERIFY_INVALID_PUBKEY_PARSING
217 (Syntax) error while parsing the retrieved public key record.
218
219
220 For verify_status == PDKIM_VERIFY_FAIL:
221
222 PDKIM_VERIFY_FAIL_BODY
223 The calculated body hash does not match the advertised body hash
224 from the bh= tag of the signature.
225
226 PDKIM_VERIFY_FAIL_MESSAGE
227 RSA verification of the signature (b= tag) failed.
228 */
229 int verify_ext_status;
230
231 /* Pointer to a public key record that was used to verify the signature.
232 See pdkim_pubkey declaration above for more information.
233 Caution: is NULL if signing or if no record was retrieved. */
234 pdkim_pubkey *pubkey;
235
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236 /* Properties below this point are used internally only ------------- */
237
238 /* Per-signature helper variables ----------------------------------- */
dcd03763 239 hctx body_hash_ctx;
2592e6c0 240
80a47a2c 241 unsigned long signed_body_bytes; /* How many body bytes we hashed */
9e70917d 242 int num_buffered_blanklines;
cb224393 243 pdkim_stringlist *headers; /* Raw headers included in the sig */
9e70917d 244
80a47a2c 245 /* Signing specific ------------------------------------------------- */
d73e45df 246 uschar * privkey; /* Private key */
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247 uschar * sign_headers; /* To-be-signed header names */
248 uschar * rawsig_no_b_val; /* Original signature header w/o b= tag value. */
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249} pdkim_signature;
250
251
252/* -------------------------------------------------------------------------- */
253/* Context to keep state between all operations. */
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254typedef struct pdkim_ctx {
255
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256#define PDKIM_MODE_SIGN BIT(0) /* if unset, mode==verify */
257#define PDKIM_DOT_TERM BIT(1) /* dot termination and unstuffing */
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258#define PDKIM_SEEN_CR BIT(2)
259#define PDKIM_SEEN_LF BIT(3)
e983e85a 260#define PDKIM_PAST_HDRS BIT(4)
b895f4b2 261#define PDKIM_SEEN_EOD BIT(5)
e983e85a 262 unsigned flags;
80a47a2c 263
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264 /* One (signing) or several chained (verification) signatures */
265 pdkim_signature *sig;
266
267 /* Callback for dns/txt query method (verification only) */
1eedc10f 268 uschar * (*dns_txt_callback)(char *);
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269
270 /* Coder's little helpers */
acec9514 271 gstring *cur_header;
7845dbb3 272 uschar *linebuf;
80a47a2c 273 int linebuf_offset;
80a47a2c 274 int num_headers;
37f8b554 275 pdkim_stringlist *headers; /* Raw headers for verification */
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276} pdkim_ctx;
277
278
279/* -------------------------------------------------------------------------- */
280/* API functions. Please see the sample code in sample/test_sign.c and
281 sample/test_verify.c for documentation.
282*/
283
284#ifdef __cplusplus
285extern "C" {
286#endif
287
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288void pdkim_init (void);
289
1eedc10f 290void pdkim_init_context (pdkim_ctx *, BOOL, uschar * (*)(char *));
9e70917d 291
80a47a2c 292DLLEXPORT
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293pdkim_signature *pdkim_init_sign (pdkim_ctx *,
294 uschar *, uschar *, uschar *, uschar *,
295 const uschar **);
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296
297DLLEXPORT
1eedc10f 298pdkim_ctx *pdkim_init_verify (uschar * (*)(char *), BOOL);
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299
300DLLEXPORT
9e70917d 301void pdkim_set_optional (pdkim_signature *, char *, char *,int, int,
f444c2c7 302 long,
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303 unsigned long,
304 unsigned long);
305
306DLLEXPORT
ef698bf6 307int pdkim_feed (pdkim_ctx *, uschar *, int);
80a47a2c 308DLLEXPORT
b9df1829 309int pdkim_feed_finish (pdkim_ctx *, pdkim_signature **, const uschar **);
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310
311DLLEXPORT
312void pdkim_free_ctx (pdkim_ctx *);
313
f7302073 314
b9df1829 315const uschar * pdkim_errstr(int);
f7302073 316
9e70917d 317uschar * dkim_sig_to_a_tag(const pdkim_signature * sig);
d73e45df 318
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319#ifdef __cplusplus
320}
321#endif
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322
323#endif