2 * PDKIM - a RFC4871 (DKIM) implementation
4 * Copyright (C) 1995 - 2018 Exim maintainers
6 * signing/verification interface
10 #include "crypt_ver.h"
15 # include "../macro_predef.h"
20 # ifdef SIGN_HAVE_ED25519
21 builtin_macro_create(US
"_CRYPTO_SIGN_ED25519");
23 # ifdef EXIM_HAVE_SHA3
24 builtin_macro_create(US
"_CRYPTO_HASH_SHA3");
29 #ifndef DISABLE_DKIM /* rest of file */
32 # error Must no DISABLE_TLS, for DKIM
36 /******************************************************************************/
38 # define EXIM_GNUTLS_LIBRARY_LOG_LEVEL 3
41 /* Logging function which can be registered with
42 * gnutls_global_set_log_function()
43 * gnutls_global_set_log_level() 0..9
45 #if EXIM_GNUTLS_LIBRARY_LOG_LEVEL >= 0
47 exim_gnutls_logger_cb(int level
, const char *message
)
49 size_t len
= strlen(message
);
52 DEBUG(D_tls
) debug_printf("GnuTLS<%d> empty debug message\n", level
);
55 DEBUG(D_tls
) debug_printf("GnuTLS<%d>: %s%s", level
, message
,
56 message
[len
-1] == '\n' ? "" : "\n");
65 #if EXIM_GNUTLS_LIBRARY_LOG_LEVEL >= 0
68 gnutls_global_set_log_function(exim_gnutls_logger_cb
);
69 /* arbitrarily chosen level; bump upto 9 for more */
70 gnutls_global_set_log_level(EXIM_GNUTLS_LIBRARY_LOG_LEVEL
);
76 /* accumulate data (gnutls-only). String to be appended must be nul-terminated. */
78 exim_dkim_data_append(gstring
* g
, uschar
* s
)
80 return string_cat(g
, s
);
85 /* import private key from PEM string in memory.
86 Return: NULL for success, or an error string */
89 exim_dkim_signing_init(const uschar
* privkey_pem
, es_ctx
* sign_ctx
)
91 gnutls_datum_t k
= { .data
= (void *)privkey_pem
, .size
= Ustrlen(privkey_pem
) };
92 gnutls_x509_privkey_t x509_key
;
96 if ( (where
= US
"internal init", rc
= gnutls_x509_privkey_init(&x509_key
))
97 || (rc
= gnutls_privkey_init(&sign_ctx
->key
))
98 || (where
= US
"privkey PEM-block import",
99 rc
= gnutls_x509_privkey_import(x509_key
, &k
, GNUTLS_X509_FMT_PEM
))
100 || (where
= US
"internal privkey transfer",
101 rc
= gnutls_privkey_import_x509(sign_ctx
->key
, x509_key
, 0))
103 return string_sprintf("%s: %s", where
, gnutls_strerror(rc
));
105 switch (rc
= gnutls_privkey_get_pk_algorithm(sign_ctx
->key
, NULL
))
107 case GNUTLS_PK_RSA
: sign_ctx
->keytype
= KEYTYPE_RSA
; break;
108 #ifdef SIGN_HAVE_ED25519
109 case GNUTLS_PK_EDDSA_ED25519
: sign_ctx
->keytype
= KEYTYPE_ED25519
; break;
111 default: return rc
< 0
112 ? CUS
gnutls_strerror(rc
)
113 : string_sprintf("Unhandled key type: %d '%s'", rc
, gnutls_pk_get_name(rc
));
121 /* allocate mem for signature (when signing) */
122 /* hash & sign data. No way to do incremental.
124 Return: NULL for success, or an error string */
127 exim_dkim_sign(es_ctx
* sign_ctx
, hashmethod hash
, blob
* data
, blob
* sig
)
129 gnutls_datum_t k_data
= { .data
= data
->data
, .size
= data
->len
};
130 gnutls_digest_algorithm_t dig
;
131 gnutls_datum_t k_sig
;
136 case HASH_SHA1
: dig
= GNUTLS_DIG_SHA1
; break;
137 case HASH_SHA2_256
: dig
= GNUTLS_DIG_SHA256
; break;
138 case HASH_SHA2_512
: dig
= GNUTLS_DIG_SHA512
; break;
139 default: return US
"nonhandled hash type";
142 if ((rc
= gnutls_privkey_sign_data(sign_ctx
->key
, dig
, 0, &k_data
, &k_sig
)))
143 return CUS
gnutls_strerror(rc
);
145 /* Don't care about deinit for the key; shortlived process */
147 sig
->data
= k_sig
.data
;
148 sig
->len
= k_sig
.size
;
154 /* import public key (from blob in memory)
155 Return: NULL for success, or an error string */
158 exim_dkim_verify_init(blob
* pubkey
, keyformat fmt
, ev_ctx
* verify_ctx
)
162 const uschar
* ret
= NULL
;
164 gnutls_pubkey_init(&verify_ctx
->key
);
165 k
.data
= pubkey
->data
;
166 k
.size
= pubkey
->len
;
171 if ((rc
= gnutls_pubkey_import(verify_ctx
->key
, &k
, GNUTLS_X509_FMT_DER
)))
172 ret
= US
gnutls_strerror(rc
);
174 #ifdef SIGN_HAVE_ED25519
175 case KEYFMT_ED25519_BARE
:
176 if ((rc
= gnutls_pubkey_import_ecc_raw(verify_ctx
->key
,
177 GNUTLS_ECC_CURVE_ED25519
, &k
, NULL
)))
178 ret
= US
gnutls_strerror(rc
);
182 ret
= US
"pubkey format not handled";
189 /* verify signature (of hash if RSA sig, of data if EC sig. No way to do incremental)
190 (given pubkey & alleged sig)
191 Return: NULL for success, or an error string */
194 exim_dkim_verify(ev_ctx
* verify_ctx
, hashmethod hash
, blob
* data_hash
, blob
* sig
)
196 gnutls_datum_t k
= { .data
= data_hash
->data
, .size
= data_hash
->len
};
197 gnutls_datum_t s
= { .data
= sig
->data
, .size
= sig
->len
};
199 const uschar
* ret
= NULL
;
201 #ifdef SIGN_HAVE_ED25519
202 if (verify_ctx
->keytype
== KEYTYPE_ED25519
)
204 if ((rc
= gnutls_pubkey_verify_data2(verify_ctx
->key
,
205 GNUTLS_SIGN_EDDSA_ED25519
, 0, &k
, &s
)) < 0)
206 ret
= US
gnutls_strerror(rc
);
211 gnutls_sign_algorithm_t algo
;
214 case HASH_SHA1
: algo
= GNUTLS_SIGN_RSA_SHA1
; break;
215 case HASH_SHA2_256
: algo
= GNUTLS_SIGN_RSA_SHA256
; break;
216 case HASH_SHA2_512
: algo
= GNUTLS_SIGN_RSA_SHA512
; break;
217 default: return US
"nonhandled hash type";
220 if ((rc
= gnutls_pubkey_verify_hash2(verify_ctx
->key
, algo
, 0, &k
, &s
)) < 0)
221 ret
= US
gnutls_strerror(rc
);
224 gnutls_pubkey_deinit(verify_ctx
->key
);
231 #elif defined(SIGN_GCRYPT)
232 /******************************************************************************/
233 /* This variant is used under pre-3.0.0 GnuTLS. Only rsa-sha1 and rsa-sha256 */
236 /* Internal service routine:
237 Read and move past an asn.1 header, checking class & tag,
238 optionally returning the data-length */
241 as_tag(blob
* der
, uschar req_cls
, long req_tag
, long * alen
)
248 debug_printf_indent("as_tag: %02x %02x %02x %02x\n",
249 der
->data
[0], der
->data
[1], der
->data
[2], der
->data
[3]);
251 if ((rc
= asn1_get_tag_der(der
->data
++, der
->len
--, &tag_class
, &taglen
, &tag
))
255 if (tag_class
!= req_cls
|| tag
!= req_tag
) return ASN1_ELEMENT_NOT_FOUND
;
257 if ((len
= asn1_get_length_der(der
->data
, der
->len
, &taglen
)) < 0)
258 return ASN1_DER_ERROR
;
259 if (alen
) *alen
= len
;
261 /* debug_printf_indent("as_tag: tlen %d dlen %d\n", taglen, (int)len); */
268 /* Internal service routine:
269 Read and move over an asn.1 integer, setting an MPI to the value
273 as_mpi(blob
* der
, gcry_mpi_t
* mpi
)
279 debug_printf_indent("%s\n", __FUNCTION__
);
281 /* integer; move past the header */
282 if ((rc
= as_tag(der
, 0, ASN1_TAG_INTEGER
, &alen
)) != ASN1_SUCCESS
)
283 return US
asn1_strerror(rc
);
286 if ((gerr
= gcry_mpi_scan(mpi
, GCRYMPI_FMT_STD
, der
->data
, alen
, NULL
)))
287 return US
gcry_strerror(gerr
);
289 /* move over the data */
290 der
->data
+= alen
; der
->len
-= alen
;
299 /* Version check should be the very first call because it
300 makes sure that important subsystems are initialized. */
301 if (!gcry_check_version (GCRYPT_VERSION
))
303 fputs ("libgcrypt version mismatch\n", stderr
);
307 /* We don't want to see any warnings, e.g. because we have not yet
308 parsed program options which might be used to suppress such
310 gcry_control (GCRYCTL_SUSPEND_SECMEM_WARN
);
312 /* ... If required, other initialization goes here. Note that the
313 process might still be running with increased privileges and that
314 the secure memory has not been initialized. */
316 /* Allocate a pool of 16k secure memory. This make the secure memory
317 available and also drops privileges where needed. */
318 gcry_control (GCRYCTL_INIT_SECMEM
, 16384, 0);
320 /* It is now okay to let Libgcrypt complain when there was/is
321 a problem with the secure memory. */
322 gcry_control (GCRYCTL_RESUME_SECMEM_WARN
);
324 /* ... If required, other initialization goes here. */
326 /* Tell Libgcrypt that initialization has completed. */
327 gcry_control (GCRYCTL_INITIALIZATION_FINISHED
, 0);
335 /* Accumulate data (gnutls-only).
336 String to be appended must be nul-terminated. */
339 exim_dkim_data_append(gstring
* g
, uschar
* s
)
346 /* import private key from PEM string in memory.
347 Only handles RSA keys.
348 Return: NULL for success, or an error string */
351 exim_dkim_signing_init(const uschar
* privkey_pem
, es_ctx
* sign_ctx
)
358 /*XXX will need extension to _spot_ as well as handle a
359 non-RSA key? I think...
360 So... this is not a PrivateKeyInfo - which would have a field
361 identifying the keytype - PrivateKeyAlgorithmIdentifier -
362 but a plain RSAPrivateKey (wrapped in PEM-headers. Can we
363 use those as a type tag? What forms are there? "BEGIN EC PRIVATE KEY" (cf. ec(1ssl))
365 How does OpenSSL PEM_read_bio_PrivateKey() deal with it?
366 gnutls_x509_privkey_import() ?
370 * RSAPrivateKey ::= SEQUENCE
372 * modulus INTEGER, -- n
373 * publicExponent INTEGER, -- e
374 * privateExponent INTEGER, -- d
375 * prime1 INTEGER, -- p
376 * prime2 INTEGER, -- q
377 * exponent1 INTEGER, -- d mod (p-1)
378 * exponent2 INTEGER, -- d mod (q-1)
379 * coefficient INTEGER, -- (inverse of q) mod p
380 * otherPrimeInfos OtherPrimeInfos OPTIONAL
382 * ECPrivateKey ::= SEQUENCE {
383 * version INTEGER { ecPrivkeyVer1(1) } (ecPrivkeyVer1),
384 * privateKey OCTET STRING,
385 * parameters [0] ECParameters {{ NamedCurve }} OPTIONAL,
386 * publicKey [1] BIT STRING OPTIONAL
388 * Hmm, only 1 useful item, and not even an integer? Wonder how we might use it...
390 - actually, gnutls_x509_privkey_import() appears to require a curve name parameter
391 value for that is an OID? a local-only integer (it's an enum in GnuTLS)?
395 ssh-keygen -t ecdsa -f foo.privkey
396 ssh-keygen -t ecdsa -b384 -f foo.privkey
397 ssh-keygen -t ecdsa -b521 -f foo.privkey
398 ssh-keygen -t ed25519 -f foo.privkey
400 < foo openssl pkcs8 -in /dev/stdin -inform PEM -nocrypt -topk8 -outform DER | od -x
402 openssl asn1parse -in foo -inform PEM -dump
403 openssl asn1parse -in foo -inform PEM -dump -stroffset 24 (??)
404 (not good for ed25519)
408 if ( !(s1
= Ustrstr(CS privkey_pem
, "-----BEGIN RSA PRIVATE KEY-----"))
409 || !(s2
= Ustrstr(CS (s1
+=31), "-----END RSA PRIVATE KEY-----" ))
411 return US
"Bad PEM wrapper";
415 if ((der
.len
= b64decode(s1
, &der
.data
)) < 0)
416 return US
"Bad PEM-DER b64 decode";
420 /* sequence; just move past the header */
421 if ((rc
= as_tag(&der
, ASN1_CLASS_STRUCTURED
, ASN1_TAG_SEQUENCE
, NULL
))
422 != ASN1_SUCCESS
) goto asn_err
;
424 /* integer version; move past the header, check is zero */
425 if ((rc
= as_tag(&der
, 0, ASN1_TAG_INTEGER
, &alen
)) != ASN1_SUCCESS
)
427 if (alen
!= 1 || *der
.data
!= 0)
428 return US
"Bad version number";
429 der
.data
++; der
.len
--;
431 if ( (s1
= as_mpi(&der
, &sign_ctx
->n
))
432 || (s1
= as_mpi(&der
, &sign_ctx
->e
))
433 || (s1
= as_mpi(&der
, &sign_ctx
->d
))
434 || (s1
= as_mpi(&der
, &sign_ctx
->p
))
435 || (s1
= as_mpi(&der
, &sign_ctx
->q
))
436 || (s1
= as_mpi(&der
, &sign_ctx
->dp
))
437 || (s1
= as_mpi(&der
, &sign_ctx
->dq
))
438 || (s1
= as_mpi(&der
, &sign_ctx
->qp
))
443 DEBUG(D_acl
) debug_printf_indent("rsa_signing_init:\n");
446 gcry_mpi_aprint (GCRYMPI_FMT_HEX
, &s
, NULL
, sign_ctx
->n
);
447 debug_printf_indent(" N : %s\n", s
);
448 gcry_mpi_aprint (GCRYMPI_FMT_HEX
, &s
, NULL
, sign_ctx
->e
);
449 debug_printf_indent(" E : %s\n", s
);
450 gcry_mpi_aprint (GCRYMPI_FMT_HEX
, &s
, NULL
, sign_ctx
->d
);
451 debug_printf_indent(" D : %s\n", s
);
452 gcry_mpi_aprint (GCRYMPI_FMT_HEX
, &s
, NULL
, sign_ctx
->p
);
453 debug_printf_indent(" P : %s\n", s
);
454 gcry_mpi_aprint (GCRYMPI_FMT_HEX
, &s
, NULL
, sign_ctx
->q
);
455 debug_printf_indent(" Q : %s\n", s
);
456 gcry_mpi_aprint (GCRYMPI_FMT_HEX
, &s
, NULL
, sign_ctx
->dp
);
457 debug_printf_indent(" DP: %s\n", s
);
458 gcry_mpi_aprint (GCRYMPI_FMT_HEX
, &s
, NULL
, sign_ctx
->dq
);
459 debug_printf_indent(" DQ: %s\n", s
);
460 gcry_mpi_aprint (GCRYMPI_FMT_HEX
, &s
, NULL
, sign_ctx
->qp
);
461 debug_printf_indent(" QP: %s\n", s
);
465 sign_ctx
->keytype
= KEYTYPE_RSA
;
468 asn_err
: return US
asn1_strerror(rc
);
473 /* allocate mem for signature (when signing) */
474 /* sign already-hashed data.
476 Return: NULL for success, or an error string */
479 exim_dkim_sign(es_ctx
* sign_ctx
, hashmethod hash
, blob
* data
, blob
* sig
)
482 gcry_sexp_t s_hash
= NULL
, s_key
= NULL
, s_sig
= NULL
;
487 /*XXX will need extension for hash types (though, possibly, should
488 be re-specced to not rehash but take an already-hashed value? Actually
489 current impl looks WRONG - it _is_ given a hash so should not be
490 re-hashing. Has this been tested?
492 Will need extension for non-RSA sugning algos. */
496 case HASH_SHA1
: sexp_hash
= "(data(flags pkcs1)(hash sha1 %b))"; break;
497 case HASH_SHA2_256
: sexp_hash
= "(data(flags pkcs1)(hash sha256 %b))"; break;
498 default: return US
"nonhandled hash type";
502 sig
->data
= store_get(SIGSPACE
, FALSE
);
504 if (gcry_mpi_cmp (sign_ctx
->p
, sign_ctx
->q
) > 0)
506 gcry_mpi_swap (sign_ctx
->p
, sign_ctx
->q
);
507 gcry_mpi_invm (sign_ctx
->qp
, sign_ctx
->p
, sign_ctx
->q
);
510 if ( (gerr
= gcry_sexp_build (&s_key
, NULL
,
511 "(private-key (rsa (n%m)(e%m)(d%m)(p%m)(q%m)(u%m)))",
512 sign_ctx
->n
, sign_ctx
->e
,
513 sign_ctx
->d
, sign_ctx
->p
,
514 sign_ctx
->q
, sign_ctx
->qp
))
515 || (gerr
= gcry_sexp_build (&s_hash
, NULL
, sexp_hash
,
516 (int) data
->len
, CS data
->data
))
517 || (gerr
= gcry_pk_sign (&s_sig
, s_hash
, s_key
))
519 return US
gcry_strerror(gerr
);
521 /* gcry_sexp_dump(s_sig); */
523 if ( !(s_sig
= gcry_sexp_find_token(s_sig
, "s", 0))
525 return US
"no sig result";
527 m_sig
= gcry_sexp_nth_mpi(s_sig
, 1, GCRYMPI_FMT_USG
);
533 gcry_mpi_aprint (GCRYMPI_FMT_HEX
, &s
, NULL
, m_sig
);
534 debug_printf_indent(" SG: %s\n", s
);
538 gerr
= gcry_mpi_print(GCRYMPI_FMT_USG
, sig
->data
, SIGSPACE
, &sig
->len
, m_sig
);
541 debug_printf_indent("signature conversion from MPI to buffer failed\n");
542 return US
gcry_strerror(gerr
);
550 /* import public key (from blob in memory)
551 Return: NULL for success, or an error string */
554 exim_dkim_verify_init(blob
* pubkey
, keyformat fmt
, ev_ctx
* verify_ctx
)
557 in code sequence per b81207d2bfa92 rsa_parse_public_key() and asn1_get_mpi()
565 uschar
* stage
= US
"S1";
567 if (fmt
!= KEYFMT_DER
) return US
"pubkey format not handled";
574 BIT STRING:RSAPublicKey
576 INTEGER:Public modulus
577 INTEGER:Public exponent
579 openssl rsa -in aux-fixed/dkim/dkim.private -pubout -outform DER | od -t x1 | head;
580 openssl rsa -in aux-fixed/dkim/dkim.private -pubout | openssl asn1parse -dump;
581 openssl rsa -in aux-fixed/dkim/dkim.private -pubout | openssl asn1parse -dump -offset 22;
584 /* sequence; just move past the header */
585 if ((rc
= as_tag(pubkey
, ASN1_CLASS_STRUCTURED
, ASN1_TAG_SEQUENCE
, NULL
))
586 != ASN1_SUCCESS
) goto asn_err
;
588 /* sequence; skip the entire thing */
589 DEBUG(D_acl
) stage
= US
"S2";
590 if ((rc
= as_tag(pubkey
, ASN1_CLASS_STRUCTURED
, ASN1_TAG_SEQUENCE
, &alen
))
591 != ASN1_SUCCESS
) goto asn_err
;
592 pubkey
->data
+= alen
; pubkey
->len
-= alen
;
595 /* bitstring: limit range to size of bitstring;
596 move over header + content wrapper */
597 DEBUG(D_acl
) stage
= US
"BS";
598 if ((rc
= as_tag(pubkey
, 0, ASN1_TAG_BIT_STRING
, &alen
)) != ASN1_SUCCESS
)
601 pubkey
->data
++; pubkey
->len
--;
603 /* sequence; just move past the header */
604 DEBUG(D_acl
) stage
= US
"S3";
605 if ((rc
= as_tag(pubkey
, ASN1_CLASS_STRUCTURED
, ASN1_TAG_SEQUENCE
, NULL
))
606 != ASN1_SUCCESS
) goto asn_err
;
608 /* read two integers */
609 DEBUG(D_acl
) stage
= US
"MPI";
610 if ( (errstr
= as_mpi(pubkey
, &verify_ctx
->n
))
611 || (errstr
= as_mpi(pubkey
, &verify_ctx
->e
))
616 DEBUG(D_acl
) debug_printf_indent("rsa_verify_init:\n");
619 gcry_mpi_aprint (GCRYMPI_FMT_HEX
, &s
, NULL
, verify_ctx
->n
);
620 debug_printf_indent(" N : %s\n", s
);
621 gcry_mpi_aprint (GCRYMPI_FMT_HEX
, &s
, NULL
, verify_ctx
->e
);
622 debug_printf_indent(" E : %s\n", s
);
629 DEBUG(D_acl
) return string_sprintf("%s: %s", stage
, asn1_strerror(rc
));
630 return US
asn1_strerror(rc
);
634 /* verify signature (of hash)
635 XXX though we appear to be doing a hash, too!
636 (given pubkey & alleged sig)
637 Return: NULL for success, or an error string */
640 exim_dkim_verify(ev_ctx
* verify_ctx
, hashmethod hash
, blob
* data_hash
, blob
* sig
)
643 cf. libgnutls 2.8.5 _wrap_gcry_pk_verify()
647 gcry_sexp_t s_sig
= NULL
, s_hash
= NULL
, s_pkey
= NULL
;
651 /*XXX needs extension for SHA512 */
654 case HASH_SHA1
: sexp_hash
= "(data(flags pkcs1)(hash sha1 %b))"; break;
655 case HASH_SHA2_256
: sexp_hash
= "(data(flags pkcs1)(hash sha256 %b))"; break;
656 default: return US
"nonhandled hash type";
659 if ( (stage
= US
"pkey sexp build",
660 gerr
= gcry_sexp_build (&s_pkey
, NULL
, "(public-key(rsa(n%m)(e%m)))",
661 verify_ctx
->n
, verify_ctx
->e
))
662 || (stage
= US
"data sexp build",
663 gerr
= gcry_sexp_build (&s_hash
, NULL
, sexp_hash
,
664 (int) data_hash
->len
, CS data_hash
->data
))
665 || (stage
= US
"sig mpi scan",
666 gerr
= gcry_mpi_scan(&m_sig
, GCRYMPI_FMT_USG
, sig
->data
, sig
->len
, NULL
))
667 || (stage
= US
"sig sexp build",
668 gerr
= gcry_sexp_build (&s_sig
, NULL
, "(sig-val(rsa(s%m)))", m_sig
))
669 || (stage
= US
"verify",
670 gerr
= gcry_pk_verify (s_sig
, s_hash
, s_pkey
))
673 DEBUG(D_acl
) debug_printf_indent("verify: error in stage '%s'\n", stage
);
674 return US
gcry_strerror(gerr
);
677 if (s_sig
) gcry_sexp_release (s_sig
);
678 if (s_hash
) gcry_sexp_release (s_hash
);
679 if (s_pkey
) gcry_sexp_release (s_pkey
);
680 gcry_mpi_release (m_sig
);
681 gcry_mpi_release (verify_ctx
->n
);
682 gcry_mpi_release (verify_ctx
->e
);
690 #elif defined(SIGN_OPENSSL)
691 /******************************************************************************/
696 ERR_load_crypto_strings();
700 /* accumulate data (was gnutls-only but now needed for OpenSSL non-EC too
701 because now using hash-and-sign interface) */
703 exim_dkim_data_append(gstring
* g
, uschar
* s
)
705 return string_cat(g
, s
);
709 /* import private key from PEM string in memory.
710 Return: NULL for success, or an error string */
713 exim_dkim_signing_init(const uschar
* privkey_pem
, es_ctx
* sign_ctx
)
715 BIO
* bp
= BIO_new_mem_buf((void *)privkey_pem
, -1);
717 if (!(sign_ctx
->key
= PEM_read_bio_PrivateKey(bp
, NULL
, NULL
, NULL
)))
718 return string_sprintf("privkey PEM-block import: %s",
719 ERR_error_string(ERR_get_error(), NULL
));
722 #ifdef SIGN_HAVE_ED25519
723 EVP_PKEY_type(EVP_PKEY_id(sign_ctx
->key
)) == EVP_PKEY_ED25519
724 ? KEYTYPE_ED25519
: KEYTYPE_RSA
;
733 /* allocate mem for signature (when signing) */
734 /* hash & sign data. Incremental not supported.
736 Return: NULL for success with the signaature in the sig blob, or an error string */
739 exim_dkim_sign(es_ctx
* sign_ctx
, hashmethod hash
, blob
* data
, blob
* sig
)
747 case HASH_NULL
: md
= NULL
; break; /* Ed25519 signing */
748 case HASH_SHA1
: md
= EVP_sha1(); break;
749 case HASH_SHA2_256
: md
= EVP_sha256(); break;
750 case HASH_SHA2_512
: md
= EVP_sha512(); break;
751 default: return US
"nonhandled hash type";
754 #ifdef SIGN_HAVE_ED25519
755 if ( (ctx
= EVP_MD_CTX_new())
756 && EVP_DigestSignInit(ctx
, NULL
, md
, NULL
, sign_ctx
->key
) > 0
757 && EVP_DigestSign(ctx
, NULL
, &siglen
, NULL
, 0) > 0
758 && (sig
->data
= store_get(siglen
, FALSE
))
760 /* Obtain the signature (slen could change here!) */
761 && EVP_DigestSign(ctx
, sig
->data
, &siglen
, data
->data
, data
->len
) > 0
764 EVP_MD_CTX_destroy(ctx
);
769 /*XXX renamed to EVP_MD_CTX_new() in 1.1.0 */
770 if ( (ctx
= EVP_MD_CTX_create())
771 && EVP_DigestSignInit(ctx
, NULL
, md
, NULL
, sign_ctx
->key
) > 0
772 && EVP_DigestSignUpdate(ctx
, data
->data
, data
->len
) > 0
773 && EVP_DigestSignFinal(ctx
, NULL
, &siglen
) > 0
774 && (sig
->data
= store_get(siglen
, FALSE
))
776 /* Obtain the signature (slen could change here!) */
777 && EVP_DigestSignFinal(ctx
, sig
->data
, &siglen
) > 0
780 EVP_MD_CTX_destroy(ctx
);
786 if (ctx
) EVP_MD_CTX_destroy(ctx
);
787 return US
ERR_error_string(ERR_get_error(), NULL
);
792 /* import public key (from blob in memory)
793 Return: NULL for success, or an error string */
796 exim_dkim_verify_init(blob
* pubkey
, keyformat fmt
, ev_ctx
* verify_ctx
)
798 const uschar
* s
= pubkey
->data
;
804 /*XXX hmm, we never free this */
805 if (!(verify_ctx
->key
= d2i_PUBKEY(NULL
, &s
, pubkey
->len
)))
806 ret
= US
ERR_error_string(ERR_get_error(), NULL
);
808 #ifdef SIGN_HAVE_ED25519
809 case KEYFMT_ED25519_BARE
:
810 if (!(verify_ctx
->key
= EVP_PKEY_new_raw_public_key(EVP_PKEY_ED25519
, NULL
,
812 ret
= US
ERR_error_string(ERR_get_error(), NULL
);
816 ret
= US
"pubkey format not handled";
826 /* verify signature (of hash, except Ed25519 where of-data)
827 (given pubkey & alleged sig)
828 Return: NULL for success, or an error string */
831 exim_dkim_verify(ev_ctx
* verify_ctx
, hashmethod hash
, blob
* data
, blob
* sig
)
837 case HASH_NULL
: md
= NULL
; break;
838 case HASH_SHA1
: md
= EVP_sha1(); break;
839 case HASH_SHA2_256
: md
= EVP_sha256(); break;
840 case HASH_SHA2_512
: md
= EVP_sha512(); break;
841 default: return US
"nonhandled hash type";
844 #ifdef SIGN_HAVE_ED25519
849 if ((ctx
= EVP_MD_CTX_new()))
851 if ( EVP_DigestVerifyInit(ctx
, NULL
, md
, NULL
, verify_ctx
->key
) > 0
852 && EVP_DigestVerify(ctx
, sig
->data
, sig
->len
, data
->data
, data
->len
) > 0
854 { EVP_MD_CTX_free(ctx
); return NULL
; }
855 EVP_MD_CTX_free(ctx
);
863 if ((ctx
= EVP_PKEY_CTX_new(verify_ctx
->key
, NULL
)))
865 if ( EVP_PKEY_verify_init(ctx
) > 0
866 && EVP_PKEY_CTX_set_rsa_padding(ctx
, RSA_PKCS1_PADDING
) > 0
867 && EVP_PKEY_CTX_set_signature_md(ctx
, md
) > 0
868 && EVP_PKEY_verify(ctx
, sig
->data
, sig
->len
,
869 data
->data
, data
->len
) == 1
871 { EVP_PKEY_CTX_free(ctx
); return NULL
; }
872 EVP_PKEY_CTX_free(ctx
);
875 if (Ustrcmp(ERR_reason_error_string(ERR_peek_error()), "wrong signature length") == 0)
876 debug_printf("sig len (from msg hdr): %d, expected (from dns pubkey) %d\n",
877 (int) sig
->len
, EVP_PKEY_size(verify_ctx
->key
));
881 return US
ERR_error_string(ERR_get_error(), NULL
);
887 /******************************************************************************/
889 #endif /*DISABLE_DKIM*/
890 #endif /*MACRO_PREDEF*/