Cutthrough: Fix bug with dot-only line
[exim.git] / src / src / pdkim / pdkim.h
CommitLineData
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1/*
2 * PDKIM - a RFC4871 (DKIM) implementation
3 *
c4ceed07 4 * Copyright (C) 2009 - 2012 Tom Kistner <tom@duncanthrax.net>
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5 *
6 * http://duncanthrax.net/pdkim/
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; either version 2 of the License, or
11 * (at your option) any later version.
12 *
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
17 *
18 * You should have received a copy of the GNU General Public License along
19 * with this program; if not, write to the Free Software Foundation, Inc.,
20 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
21 */
22
80a47a2c 23/* -------------------------------------------------------------------------- */
80a47a2c 24/* Length of the preallocated buffer for the "answer" from the dns/txt
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25 callback function. This should match the maximum RDLENGTH from DNS. */
26#define PDKIM_DNS_TXT_MAX_RECLEN (1 << 16)
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27
28/* -------------------------------------------------------------------------- */
29/* Function success / error codes */
30#define PDKIM_OK 0
31#define PDKIM_FAIL -1
32#define PDKIM_ERR_OOM -100
33#define PDKIM_ERR_RSA_PRIVKEY -101
34#define PDKIM_ERR_RSA_SIGNING -102
35#define PDKIM_ERR_LONG_LINE -103
36#define PDKIM_ERR_BUFFER_TOO_SMALL -104
37
38/* -------------------------------------------------------------------------- */
39/* Main/Extended verification status */
40#define PDKIM_VERIFY_NONE 0
41#define PDKIM_VERIFY_INVALID 1
42#define PDKIM_VERIFY_FAIL 2
43#define PDKIM_VERIFY_PASS 3
44
45#define PDKIM_VERIFY_FAIL_BODY 1
46#define PDKIM_VERIFY_FAIL_MESSAGE 2
47#define PDKIM_VERIFY_INVALID_PUBKEY_UNAVAILABLE 3
48#define PDKIM_VERIFY_INVALID_BUFFER_SIZE 4
49#define PDKIM_VERIFY_INVALID_PUBKEY_PARSING 5
50
51/* -------------------------------------------------------------------------- */
52/* Some parameter values */
53#define PDKIM_QUERYMETHOD_DNS_TXT 0
54
55#define PDKIM_ALGO_RSA_SHA256 0
56#define PDKIM_ALGO_RSA_SHA1 1
57
58#define PDKIM_CANON_SIMPLE 0
59#define PDKIM_CANON_RELAXED 1
60
61#define PDKIM_HASH_SHA256 0
62#define PDKIM_HASH_SHA1 1
63
64#define PDKIM_KEYTYPE_RSA 0
65
66/* -------------------------------------------------------------------------- */
67/* Some required forward declarations, please ignore */
68typedef struct pdkim_stringlist pdkim_stringlist;
69typedef struct pdkim_str pdkim_str;
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70typedef struct sha1_context sha1_context;
71typedef struct sha2_context sha2_context;
72#define HAVE_SHA1_CONTEXT
73#define HAVE_SHA2_CONTEXT
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74
75/* -------------------------------------------------------------------------- */
76/* Some concessions towards Redmond */
77#ifdef WINDOWS
78#define snprintf _snprintf
79#define strcasecmp _stricmp
80#define strncasecmp _strnicmp
81#define DLLEXPORT __declspec(dllexport)
82#else
83#define DLLEXPORT
84#endif
85
86
87/* -------------------------------------------------------------------------- */
88/* Public key as (usually) fetched from DNS */
89typedef struct pdkim_pubkey {
90 char *version; /* v= */
91 char *granularity; /* g= */
92
93 char *hashes; /* h= */
94 char *keytype; /* k= */
95 char *srvtype; /* s= */
96 char *notes; /* n= */
97
98 char *key; /* p= */
99 int key_len;
100
101 int testing; /* t=y */
102 int no_subdomaining; /* t=s */
103} pdkim_pubkey;
104
105/* -------------------------------------------------------------------------- */
106/* Signature as it appears in a DKIM-Signature header */
107typedef struct pdkim_signature {
108
109 /* Bits stored in a DKIM signature header --------------------------- */
110
111 /* (v=) The version, as an integer. Currently, always "1" */
112 int version;
113
114 /* (a=) The signature algorithm. Either PDKIM_ALGO_RSA_SHA256
115 or PDKIM_ALGO_RSA_SHA1 */
116 int algo;
117
118 /* (c=x/) Header canonicalization method. Either PDKIM_CANON_SIMPLE
119 or PDKIM_CANON_RELAXED */
120 int canon_headers;
121
122 /* (c=/x) Body canonicalization method. Either PDKIM_CANON_SIMPLE
123 or PDKIM_CANON_RELAXED */
124 int canon_body;
125
126 /* (q=) Query Method. Currently, only PDKIM_QUERYMETHOD_DNS_TXT
127 is specified */
128 int querymethod;
129
130 /* (s=) The selector string as given in the signature */
131 char *selector;
132
133 /* (d=) The domain as given in the signature */
134 char *domain;
135
136 /* (i=) The identity as given in the signature */
137 char *identity;
138
139 /* (t=) Timestamp of signature creation */
140 unsigned long created;
141
142 /* (x=) Timestamp of expiry of signature */
143 unsigned long expires;
144
145 /* (l=) Amount of hashed body bytes (after canonicalization). Default
146 is -1. Note: a value of 0 means that the body is unsigned! */
147 long bodylength;
148
149 /* (h=) Colon-separated list of header names that are included in the
150 signature */
151 char *headernames;
152
153 /* (z=) */
154 char *copiedheaders;
155
156 /* (b=) Raw signature data, along with its length in bytes */
157 char *sigdata;
158 int sigdata_len;
159
160 /* (bh=) Raw body hash data, along with its length in bytes */
161 char *bodyhash;
162 int bodyhash_len;
163
164 /* Folded DKIM-Signature: header. Singing only, NULL for verifying.
165 Ready for insertion into the message. Note: Folded using CRLFTB,
166 but final line terminator is NOT included. Note2: This buffer is
167 free()d when you call pdkim_free_ctx(). */
168 char *signature_header;
169
170 /* The main verification status. Verification only. One of:
171
172 PDKIM_VERIFY_NONE Verification was not attempted. This status
173 should not appear.
174
175 PDKIM_VERIFY_INVALID There was an error while trying to verify
176 the signature. A more precise description
177 is available in verify_ext_status.
178
179 PDKIM_VERIFY_FAIL Verification failed because either the body
180 hash did not match, or the signature verification
181 failed. This means the message was modified.
182 Check verify_ext_status for the exact reason.
183
184 PDKIM_VERIFY_PASS Verification succeeded.
185 */
186 int verify_status;
187
188 /* Extended verification status. Verification only. Depending on the value
189 of verify_status, it can contain:
190
191 For verify_status == PDKIM_VERIFY_INVALID:
192
193 PDKIM_VERIFY_INVALID_PUBKEY_UNAVAILABLE
194 Unable to retrieve a public key container.
195
196 PDKIM_VERIFY_INVALID_BUFFER_SIZE
197 Either the DNS name constructed to retrieve the public key record
198 does not fit into PDKIM_DNS_TXT_MAX_NAMELEN bytes, or the retrieved
199 record is longer than PDKIM_DNS_TXT_MAX_RECLEN bytes.
200
201 PDKIM_VERIFY_INVALID_PUBKEY_PARSING
202 (Syntax) error while parsing the retrieved public key record.
203
204
205 For verify_status == PDKIM_VERIFY_FAIL:
206
207 PDKIM_VERIFY_FAIL_BODY
208 The calculated body hash does not match the advertised body hash
209 from the bh= tag of the signature.
210
211 PDKIM_VERIFY_FAIL_MESSAGE
212 RSA verification of the signature (b= tag) failed.
213 */
214 int verify_ext_status;
215
216 /* Pointer to a public key record that was used to verify the signature.
217 See pdkim_pubkey declaration above for more information.
218 Caution: is NULL if signing or if no record was retrieved. */
219 pdkim_pubkey *pubkey;
220
221 /* Pointer to the next pdkim_signature signature. NULL if signing or if
222 this is the last signature. */
223 void *next;
224
225 /* Properties below this point are used internally only ------------- */
226
227 /* Per-signature helper variables ----------------------------------- */
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228#ifdef SHA_OPENSSL
229 SHA_CTX sha1_body; /* SHA1 block */
230 SHA256_CTX sha2_body; /* SHA256 block */
231#elif defined(SHA_GNUTLS)
f444c2c7 232 gnutls_hash_hd_t sha_body; /* Either SHA1 or SHA256 block */
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233#elif defined(SHA_POLARSSL)
234 sha1_context *sha1_body; /* SHA1 block */
235 sha2_context *sha2_body; /* SHA256 block */
f444c2c7 236#endif
80a47a2c 237 unsigned long signed_body_bytes; /* How many body bytes we hashed */
cb224393 238 pdkim_stringlist *headers; /* Raw headers included in the sig */
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239 /* Signing specific ------------------------------------------------- */
240 char *rsa_privkey; /* Private RSA key */
241 char *sign_headers; /* To-be-signed header names */
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242 char *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#define PDKIM_MODE_SIGN 0
249#define PDKIM_MODE_VERIFY 1
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250typedef struct pdkim_ctx {
251
252 /* PDKIM_MODE_VERIFY or PDKIM_MODE_SIGN */
253 int mode;
254
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255 /* One (signing) or several chained (verification) signatures */
256 pdkim_signature *sig;
257
258 /* Callback for dns/txt query method (verification only) */
259 int(*dns_txt_callback)(char *, char *);
260
261 /* Coder's little helpers */
262 pdkim_str *cur_header;
263 char *linebuf;
264 int linebuf_offset;
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265 BOOL seen_lf;
266 BOOL seen_eod;
267 BOOL past_headers;
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268 int num_buffered_crlf;
269 int num_headers;
37f8b554 270 pdkim_stringlist *headers; /* Raw headers for verification */
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271} pdkim_ctx;
272
273
274/* -------------------------------------------------------------------------- */
275/* API functions. Please see the sample code in sample/test_sign.c and
276 sample/test_verify.c for documentation.
277*/
278
279#ifdef __cplusplus
280extern "C" {
281#endif
282
283DLLEXPORT
f444c2c7 284pdkim_ctx *pdkim_init_sign (char *, char *, char *, int);
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285
286DLLEXPORT
0d04a285 287pdkim_ctx *pdkim_init_verify (int(*)(char *, char *));
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288
289DLLEXPORT
290int pdkim_set_optional (pdkim_ctx *, char *, char *,int, int,
f444c2c7 291 long,
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292 unsigned long,
293 unsigned long);
294
295DLLEXPORT
296int pdkim_feed (pdkim_ctx *, char *, int);
297DLLEXPORT
298int pdkim_feed_finish (pdkim_ctx *, pdkim_signature **);
299
300DLLEXPORT
301void pdkim_free_ctx (pdkim_ctx *);
302
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303#ifdef __cplusplus
304}
305#endif