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 Need SUPPORT_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
;
95 if ( (rc
= gnutls_x509_privkey_init(&x509_key
))
96 || (rc
= gnutls_x509_privkey_import(x509_key
, &k
, GNUTLS_X509_FMT_PEM
))
97 || (rc
= gnutls_privkey_init(&sign_ctx
->key
))
98 || (rc
= gnutls_privkey_import_x509(sign_ctx
->key
, x509_key
, 0))
100 return CUS
gnutls_strerror(rc
);
102 switch (rc
= gnutls_privkey_get_pk_algorithm(sign_ctx
->key
, NULL
))
104 case GNUTLS_PK_RSA
: sign_ctx
->keytype
= KEYTYPE_RSA
; break;
105 #ifdef SIGN_HAVE_ED25519
106 case GNUTLS_PK_EDDSA_ED25519
: sign_ctx
->keytype
= KEYTYPE_ED25519
; break;
108 default: return rc
< 0
109 ? CUS
gnutls_strerror(rc
)
110 : string_sprintf("Unhandled key type: %d '%s'", rc
, gnutls_pk_get_name(rc
));
118 /* allocate mem for signature (when signing) */
119 /* hash & sign data. No way to do incremental.
121 Return: NULL for success, or an error string */
124 exim_dkim_sign(es_ctx
* sign_ctx
, hashmethod hash
, blob
* data
, blob
* sig
)
126 gnutls_datum_t k_data
= { .data
= data
->data
, .size
= data
->len
};
127 gnutls_digest_algorithm_t dig
;
128 gnutls_datum_t k_sig
;
133 case HASH_SHA1
: dig
= GNUTLS_DIG_SHA1
; break;
134 case HASH_SHA2_256
: dig
= GNUTLS_DIG_SHA256
; break;
135 case HASH_SHA2_512
: dig
= GNUTLS_DIG_SHA512
; break;
136 default: return US
"nonhandled hash type";
139 if ((rc
= gnutls_privkey_sign_data(sign_ctx
->key
, dig
, 0, &k_data
, &k_sig
)))
140 return CUS
gnutls_strerror(rc
);
142 /* Don't care about deinit for the key; shortlived process */
144 sig
->data
= k_sig
.data
;
145 sig
->len
= k_sig
.size
;
151 /* import public key (from blob in memory)
152 Return: NULL for success, or an error string */
155 exim_dkim_verify_init(blob
* pubkey
, keyformat fmt
, ev_ctx
* verify_ctx
)
159 const uschar
* ret
= NULL
;
161 gnutls_pubkey_init(&verify_ctx
->key
);
162 k
.data
= pubkey
->data
;
163 k
.size
= pubkey
->len
;
168 if ((rc
= gnutls_pubkey_import(verify_ctx
->key
, &k
, GNUTLS_X509_FMT_DER
)))
169 ret
= gnutls_strerror(rc
);
171 #ifdef SIGN_HAVE_ED25519
172 case KEYFMT_ED25519_BARE
:
173 if ((rc
= gnutls_pubkey_import_ecc_raw(verify_ctx
->key
,
174 GNUTLS_ECC_CURVE_ED25519
, &k
, NULL
)))
175 ret
= gnutls_strerror(rc
);
179 ret
= US
"pubkey format not handled";
186 /* verify signature (of hash if RSA sig, of data if EC sig. No way to do incremental)
187 (given pubkey & alleged sig)
188 Return: NULL for success, or an error string */
191 exim_dkim_verify(ev_ctx
* verify_ctx
, hashmethod hash
, blob
* data_hash
, blob
* sig
)
193 gnutls_datum_t k
= { .data
= data_hash
->data
, .size
= data_hash
->len
};
194 gnutls_datum_t s
= { .data
= sig
->data
, .size
= sig
->len
};
196 const uschar
* ret
= NULL
;
198 #ifdef SIGN_HAVE_ED25519
199 if (verify_ctx
->keytype
== KEYTYPE_ED25519
)
201 if ((rc
= gnutls_pubkey_verify_data2(verify_ctx
->key
,
202 GNUTLS_SIGN_EDDSA_ED25519
, 0, &k
, &s
)) < 0)
203 ret
= gnutls_strerror(rc
);
208 gnutls_sign_algorithm_t algo
;
211 case HASH_SHA1
: algo
= GNUTLS_SIGN_RSA_SHA1
; break;
212 case HASH_SHA2_256
: algo
= GNUTLS_SIGN_RSA_SHA256
; break;
213 case HASH_SHA2_512
: algo
= GNUTLS_SIGN_RSA_SHA512
; break;
214 default: return US
"nonhandled hash type";
217 if ((rc
= gnutls_pubkey_verify_hash2(verify_ctx
->key
, algo
, 0, &k
, &s
)) < 0)
218 ret
= gnutls_strerror(rc
);
221 gnutls_pubkey_deinit(verify_ctx
->key
);
228 #elif defined(SIGN_GCRYPT)
229 /******************************************************************************/
230 /* This variant is used under pre-3.0.0 GnuTLS. Only rsa-sha1 and rsa-sha256 */
233 /* Internal service routine:
234 Read and move past an asn.1 header, checking class & tag,
235 optionally returning the data-length */
238 as_tag(blob
* der
, uschar req_cls
, long req_tag
, long * alen
)
245 debug_printf_indent("as_tag: %02x %02x %02x %02x\n",
246 der
->data
[0], der
->data
[1], der
->data
[2], der
->data
[3]);
248 if ((rc
= asn1_get_tag_der(der
->data
++, der
->len
--, &tag_class
, &taglen
, &tag
))
252 if (tag_class
!= req_cls
|| tag
!= req_tag
) return ASN1_ELEMENT_NOT_FOUND
;
254 if ((len
= asn1_get_length_der(der
->data
, der
->len
, &taglen
)) < 0)
255 return ASN1_DER_ERROR
;
256 if (alen
) *alen
= len
;
258 /* debug_printf_indent("as_tag: tlen %d dlen %d\n", taglen, (int)len); */
265 /* Internal service routine:
266 Read and move over an asn.1 integer, setting an MPI to the value
270 as_mpi(blob
* der
, gcry_mpi_t
* mpi
)
276 debug_printf_indent("%s\n", __FUNCTION__
);
278 /* integer; move past the header */
279 if ((rc
= as_tag(der
, 0, ASN1_TAG_INTEGER
, &alen
)) != ASN1_SUCCESS
)
280 return US
asn1_strerror(rc
);
283 if ((gerr
= gcry_mpi_scan(mpi
, GCRYMPI_FMT_STD
, der
->data
, alen
, NULL
)))
284 return US
gcry_strerror(gerr
);
286 /* move over the data */
287 der
->data
+= alen
; der
->len
-= alen
;
296 /* Version check should be the very first call because it
297 makes sure that important subsystems are initialized. */
298 if (!gcry_check_version (GCRYPT_VERSION
))
300 fputs ("libgcrypt version mismatch\n", stderr
);
304 /* We don't want to see any warnings, e.g. because we have not yet
305 parsed program options which might be used to suppress such
307 gcry_control (GCRYCTL_SUSPEND_SECMEM_WARN
);
309 /* ... If required, other initialization goes here. Note that the
310 process might still be running with increased privileges and that
311 the secure memory has not been initialized. */
313 /* Allocate a pool of 16k secure memory. This make the secure memory
314 available and also drops privileges where needed. */
315 gcry_control (GCRYCTL_INIT_SECMEM
, 16384, 0);
317 /* It is now okay to let Libgcrypt complain when there was/is
318 a problem with the secure memory. */
319 gcry_control (GCRYCTL_RESUME_SECMEM_WARN
);
321 /* ... If required, other initialization goes here. */
323 /* Tell Libgcrypt that initialization has completed. */
324 gcry_control (GCRYCTL_INITIALIZATION_FINISHED
, 0);
332 /* Accumulate data (gnutls-only).
333 String to be appended must be nul-terminated. */
336 exim_dkim_data_append(gstring
* g
, uschar
* s
)
343 /* import private key from PEM string in memory.
344 Only handles RSA keys.
345 Return: NULL for success, or an error string */
348 exim_dkim_signing_init(const uschar
* privkey_pem
, es_ctx
* sign_ctx
)
355 /*XXX will need extension to _spot_ as well as handle a
356 non-RSA key? I think...
357 So... this is not a PrivateKeyInfo - which would have a field
358 identifying the keytype - PrivateKeyAlgorithmIdentifier -
359 but a plain RSAPrivateKey (wrapped in PEM-headers. Can we
360 use those as a type tag? What forms are there? "BEGIN EC PRIVATE KEY" (cf. ec(1ssl))
362 How does OpenSSL PEM_read_bio_PrivateKey() deal with it?
363 gnutls_x509_privkey_import() ?
367 * RSAPrivateKey ::= SEQUENCE
369 * modulus INTEGER, -- n
370 * publicExponent INTEGER, -- e
371 * privateExponent INTEGER, -- d
372 * prime1 INTEGER, -- p
373 * prime2 INTEGER, -- q
374 * exponent1 INTEGER, -- d mod (p-1)
375 * exponent2 INTEGER, -- d mod (q-1)
376 * coefficient INTEGER, -- (inverse of q) mod p
377 * otherPrimeInfos OtherPrimeInfos OPTIONAL
379 * ECPrivateKey ::= SEQUENCE {
380 * version INTEGER { ecPrivkeyVer1(1) } (ecPrivkeyVer1),
381 * privateKey OCTET STRING,
382 * parameters [0] ECParameters {{ NamedCurve }} OPTIONAL,
383 * publicKey [1] BIT STRING OPTIONAL
385 * Hmm, only 1 useful item, and not even an integer? Wonder how we might use it...
387 - actually, gnutls_x509_privkey_import() appears to require a curve name parameter
388 value for that is an OID? a local-only integer (it's an enum in GnuTLS)?
392 ssh-keygen -t ecdsa -f foo.privkey
393 ssh-keygen -t ecdsa -b384 -f foo.privkey
394 ssh-keygen -t ecdsa -b521 -f foo.privkey
395 ssh-keygen -t ed25519 -f foo.privkey
397 < foo openssl pkcs8 -in /dev/stdin -inform PEM -nocrypt -topk8 -outform DER | od -x
399 openssl asn1parse -in foo -inform PEM -dump
400 openssl asn1parse -in foo -inform PEM -dump -stroffset 24 (??)
401 (not good for ed25519)
405 if ( !(s1
= Ustrstr(CS privkey_pem
, "-----BEGIN RSA PRIVATE KEY-----"))
406 || !(s2
= Ustrstr(CS (s1
+=31), "-----END RSA PRIVATE KEY-----" ))
408 return US
"Bad PEM wrapper";
412 if ((der
.len
= b64decode(s1
, &der
.data
)) < 0)
413 return US
"Bad PEM-DER b64 decode";
417 /* sequence; just move past the header */
418 if ((rc
= as_tag(&der
, ASN1_CLASS_STRUCTURED
, ASN1_TAG_SEQUENCE
, NULL
))
419 != ASN1_SUCCESS
) goto asn_err
;
421 /* integer version; move past the header, check is zero */
422 if ((rc
= as_tag(&der
, 0, ASN1_TAG_INTEGER
, &alen
)) != ASN1_SUCCESS
)
424 if (alen
!= 1 || *der
.data
!= 0)
425 return US
"Bad version number";
426 der
.data
++; der
.len
--;
428 if ( (s1
= as_mpi(&der
, &sign_ctx
->n
))
429 || (s1
= as_mpi(&der
, &sign_ctx
->e
))
430 || (s1
= as_mpi(&der
, &sign_ctx
->d
))
431 || (s1
= as_mpi(&der
, &sign_ctx
->p
))
432 || (s1
= as_mpi(&der
, &sign_ctx
->q
))
433 || (s1
= as_mpi(&der
, &sign_ctx
->dp
))
434 || (s1
= as_mpi(&der
, &sign_ctx
->dq
))
435 || (s1
= as_mpi(&der
, &sign_ctx
->qp
))
440 DEBUG(D_acl
) debug_printf_indent("rsa_signing_init:\n");
443 gcry_mpi_aprint (GCRYMPI_FMT_HEX
, &s
, NULL
, sign_ctx
->n
);
444 debug_printf_indent(" N : %s\n", s
);
445 gcry_mpi_aprint (GCRYMPI_FMT_HEX
, &s
, NULL
, sign_ctx
->e
);
446 debug_printf_indent(" E : %s\n", s
);
447 gcry_mpi_aprint (GCRYMPI_FMT_HEX
, &s
, NULL
, sign_ctx
->d
);
448 debug_printf_indent(" D : %s\n", s
);
449 gcry_mpi_aprint (GCRYMPI_FMT_HEX
, &s
, NULL
, sign_ctx
->p
);
450 debug_printf_indent(" P : %s\n", s
);
451 gcry_mpi_aprint (GCRYMPI_FMT_HEX
, &s
, NULL
, sign_ctx
->q
);
452 debug_printf_indent(" Q : %s\n", s
);
453 gcry_mpi_aprint (GCRYMPI_FMT_HEX
, &s
, NULL
, sign_ctx
->dp
);
454 debug_printf_indent(" DP: %s\n", s
);
455 gcry_mpi_aprint (GCRYMPI_FMT_HEX
, &s
, NULL
, sign_ctx
->dq
);
456 debug_printf_indent(" DQ: %s\n", s
);
457 gcry_mpi_aprint (GCRYMPI_FMT_HEX
, &s
, NULL
, sign_ctx
->qp
);
458 debug_printf_indent(" QP: %s\n", s
);
462 sign_ctx
->keytype
= KEYTYPE_RSA
;
465 asn_err
: return US
asn1_strerror(rc
);
470 /* allocate mem for signature (when signing) */
471 /* sign already-hashed data.
473 Return: NULL for success, or an error string */
476 exim_dkim_sign(es_ctx
* sign_ctx
, hashmethod hash
, blob
* data
, blob
* sig
)
479 gcry_sexp_t s_hash
= NULL
, s_key
= NULL
, s_sig
= NULL
;
484 /*XXX will need extension for hash types (though, possibly, should
485 be re-specced to not rehash but take an already-hashed value? Actually
486 current impl looks WRONG - it _is_ given a hash so should not be
487 re-hashing. Has this been tested?
489 Will need extension for non-RSA sugning algos. */
493 case HASH_SHA1
: sexp_hash
= "(data(flags pkcs1)(hash sha1 %b))"; break;
494 case HASH_SHA2_256
: sexp_hash
= "(data(flags pkcs1)(hash sha256 %b))"; break;
495 default: return US
"nonhandled hash type";
499 sig
->data
= store_get(SIGSPACE
);
501 if (gcry_mpi_cmp (sign_ctx
->p
, sign_ctx
->q
) > 0)
503 gcry_mpi_swap (sign_ctx
->p
, sign_ctx
->q
);
504 gcry_mpi_invm (sign_ctx
->qp
, sign_ctx
->p
, sign_ctx
->q
);
507 if ( (gerr
= gcry_sexp_build (&s_key
, NULL
,
508 "(private-key (rsa (n%m)(e%m)(d%m)(p%m)(q%m)(u%m)))",
509 sign_ctx
->n
, sign_ctx
->e
,
510 sign_ctx
->d
, sign_ctx
->p
,
511 sign_ctx
->q
, sign_ctx
->qp
))
512 || (gerr
= gcry_sexp_build (&s_hash
, NULL
, sexp_hash
,
513 (int) data
->len
, CS data
->data
))
514 || (gerr
= gcry_pk_sign (&s_sig
, s_hash
, s_key
))
516 return US
gcry_strerror(gerr
);
518 /* gcry_sexp_dump(s_sig); */
520 if ( !(s_sig
= gcry_sexp_find_token(s_sig
, "s", 0))
522 return US
"no sig result";
524 m_sig
= gcry_sexp_nth_mpi(s_sig
, 1, GCRYMPI_FMT_USG
);
530 gcry_mpi_aprint (GCRYMPI_FMT_HEX
, &s
, NULL
, m_sig
);
531 debug_printf_indent(" SG: %s\n", s
);
535 gerr
= gcry_mpi_print(GCRYMPI_FMT_USG
, sig
->data
, SIGSPACE
, &sig
->len
, m_sig
);
538 debug_printf_indent("signature conversion from MPI to buffer failed\n");
539 return US
gcry_strerror(gerr
);
547 /* import public key (from blob in memory)
548 Return: NULL for success, or an error string */
551 exim_dkim_verify_init(blob
* pubkey
, keyformat fmt
, ev_ctx
* verify_ctx
)
554 in code sequence per b81207d2bfa92 rsa_parse_public_key() and asn1_get_mpi()
562 uschar
* stage
= US
"S1";
564 if (fmt
!= KEYFMT_DER
) return US
"pubkey format not handled";
571 BIT STRING:RSAPublicKey
573 INTEGER:Public modulus
574 INTEGER:Public exponent
576 openssl rsa -in aux-fixed/dkim/dkim.private -pubout -outform DER | od -t x1 | head;
577 openssl rsa -in aux-fixed/dkim/dkim.private -pubout | openssl asn1parse -dump;
578 openssl rsa -in aux-fixed/dkim/dkim.private -pubout | openssl asn1parse -dump -offset 22;
581 /* sequence; just move past the header */
582 if ((rc
= as_tag(pubkey
, ASN1_CLASS_STRUCTURED
, ASN1_TAG_SEQUENCE
, NULL
))
583 != ASN1_SUCCESS
) goto asn_err
;
585 /* sequence; skip the entire thing */
586 DEBUG(D_acl
) stage
= US
"S2";
587 if ((rc
= as_tag(pubkey
, ASN1_CLASS_STRUCTURED
, ASN1_TAG_SEQUENCE
, &alen
))
588 != ASN1_SUCCESS
) goto asn_err
;
589 pubkey
->data
+= alen
; pubkey
->len
-= alen
;
592 /* bitstring: limit range to size of bitstring;
593 move over header + content wrapper */
594 DEBUG(D_acl
) stage
= US
"BS";
595 if ((rc
= as_tag(pubkey
, 0, ASN1_TAG_BIT_STRING
, &alen
)) != ASN1_SUCCESS
)
598 pubkey
->data
++; pubkey
->len
--;
600 /* sequence; just move past the header */
601 DEBUG(D_acl
) stage
= US
"S3";
602 if ((rc
= as_tag(pubkey
, ASN1_CLASS_STRUCTURED
, ASN1_TAG_SEQUENCE
, NULL
))
603 != ASN1_SUCCESS
) goto asn_err
;
605 /* read two integers */
606 DEBUG(D_acl
) stage
= US
"MPI";
607 if ( (errstr
= as_mpi(pubkey
, &verify_ctx
->n
))
608 || (errstr
= as_mpi(pubkey
, &verify_ctx
->e
))
613 DEBUG(D_acl
) debug_printf_indent("rsa_verify_init:\n");
616 gcry_mpi_aprint (GCRYMPI_FMT_HEX
, &s
, NULL
, verify_ctx
->n
);
617 debug_printf_indent(" N : %s\n", s
);
618 gcry_mpi_aprint (GCRYMPI_FMT_HEX
, &s
, NULL
, verify_ctx
->e
);
619 debug_printf_indent(" E : %s\n", s
);
626 DEBUG(D_acl
) return string_sprintf("%s: %s", stage
, asn1_strerror(rc
));
627 return US
asn1_strerror(rc
);
631 /* verify signature (of hash)
632 XXX though we appear to be doing a hash, too!
633 (given pubkey & alleged sig)
634 Return: NULL for success, or an error string */
637 exim_dkim_verify(ev_ctx
* verify_ctx
, hashmethod hash
, blob
* data_hash
, blob
* sig
)
640 cf. libgnutls 2.8.5 _wrap_gcry_pk_verify()
644 gcry_sexp_t s_sig
= NULL
, s_hash
= NULL
, s_pkey
= NULL
;
648 /*XXX needs extension for SHA512 */
651 case HASH_SHA1
: sexp_hash
= "(data(flags pkcs1)(hash sha1 %b))"; break;
652 case HASH_SHA2_256
: sexp_hash
= "(data(flags pkcs1)(hash sha256 %b))"; break;
653 default: return US
"nonhandled hash type";
656 if ( (stage
= US
"pkey sexp build",
657 gerr
= gcry_sexp_build (&s_pkey
, NULL
, "(public-key(rsa(n%m)(e%m)))",
658 verify_ctx
->n
, verify_ctx
->e
))
659 || (stage
= US
"data sexp build",
660 gerr
= gcry_sexp_build (&s_hash
, NULL
, sexp_hash
,
661 (int) data_hash
->len
, CS data_hash
->data
))
662 || (stage
= US
"sig mpi scan",
663 gerr
= gcry_mpi_scan(&m_sig
, GCRYMPI_FMT_USG
, sig
->data
, sig
->len
, NULL
))
664 || (stage
= US
"sig sexp build",
665 gerr
= gcry_sexp_build (&s_sig
, NULL
, "(sig-val(rsa(s%m)))", m_sig
))
666 || (stage
= US
"verify",
667 gerr
= gcry_pk_verify (s_sig
, s_hash
, s_pkey
))
670 DEBUG(D_acl
) debug_printf_indent("verify: error in stage '%s'\n", stage
);
671 return US
gcry_strerror(gerr
);
674 if (s_sig
) gcry_sexp_release (s_sig
);
675 if (s_hash
) gcry_sexp_release (s_hash
);
676 if (s_pkey
) gcry_sexp_release (s_pkey
);
677 gcry_mpi_release (m_sig
);
678 gcry_mpi_release (verify_ctx
->n
);
679 gcry_mpi_release (verify_ctx
->e
);
687 #elif defined(SIGN_OPENSSL)
688 /******************************************************************************/
693 ERR_load_crypto_strings();
697 /* accumulate data (was gnutls-only but now needed for OpenSSL non-EC too
698 because now using hash-and-sign interface) */
700 exim_dkim_data_append(gstring
* g
, uschar
* s
)
702 return string_cat(g
, s
);
706 /* import private key from PEM string in memory.
707 Return: NULL for success, or an error string */
710 exim_dkim_signing_init(const uschar
* privkey_pem
, es_ctx
* sign_ctx
)
712 BIO
* bp
= BIO_new_mem_buf(privkey_pem
, -1);
714 if (!(sign_ctx
->key
= PEM_read_bio_PrivateKey(bp
, NULL
, NULL
, NULL
)))
715 return US
ERR_error_string(ERR_get_error(), NULL
);
718 #ifdef SIGN_HAVE_ED25519
719 EVP_PKEY_type(EVP_PKEY_id(sign_ctx
->key
)) == EVP_PKEY_ED25519
720 ? KEYTYPE_ED25519
: KEYTYPE_RSA
;
729 /* allocate mem for signature (when signing) */
730 /* hash & sign data. Incremental not supported.
732 Return: NULL for success with the signaature in the sig blob, or an error string */
735 exim_dkim_sign(es_ctx
* sign_ctx
, hashmethod hash
, blob
* data
, blob
* sig
)
743 case HASH_NULL
: md
= NULL
; break; /* Ed25519 signing */
744 case HASH_SHA1
: md
= EVP_sha1(); break;
745 case HASH_SHA2_256
: md
= EVP_sha256(); break;
746 case HASH_SHA2_512
: md
= EVP_sha512(); break;
747 default: return US
"nonhandled hash type";
750 #ifdef SIGN_HAVE_ED25519
751 if ( (ctx
= EVP_MD_CTX_new())
752 && EVP_DigestSignInit(ctx
, NULL
, md
, NULL
, sign_ctx
->key
) > 0
753 && EVP_DigestSign(ctx
, NULL
, &siglen
, NULL
, 0) > 0
754 && (sig
->data
= store_get(siglen
))
756 /* Obtain the signature (slen could change here!) */
757 && EVP_DigestSign(ctx
, sig
->data
, &siglen
, data
->data
, data
->len
) > 0
760 EVP_MD_CTX_destroy(ctx
);
765 /*XXX renamed to EVP_MD_CTX_new() in 1.1.0 */
766 if ( (ctx
= EVP_MD_CTX_create())
767 && EVP_DigestSignInit(ctx
, NULL
, md
, NULL
, sign_ctx
->key
) > 0
768 && EVP_DigestSignUpdate(ctx
, data
->data
, data
->len
) > 0
769 && EVP_DigestSignFinal(ctx
, NULL
, &siglen
) > 0
770 && (sig
->data
= store_get(siglen
))
772 /* Obtain the signature (slen could change here!) */
773 && EVP_DigestSignFinal(ctx
, sig
->data
, &siglen
) > 0
776 EVP_MD_CTX_destroy(ctx
);
782 if (ctx
) EVP_MD_CTX_destroy(ctx
);
783 return US
ERR_error_string(ERR_get_error(), NULL
);
788 /* import public key (from blob in memory)
789 Return: NULL for success, or an error string */
792 exim_dkim_verify_init(blob
* pubkey
, keyformat fmt
, ev_ctx
* verify_ctx
)
794 const uschar
* s
= pubkey
->data
;
800 /*XXX hmm, we never free this */
801 if (!(verify_ctx
->key
= d2i_PUBKEY(NULL
, &s
, pubkey
->len
)))
802 ret
= US
ERR_error_string(ERR_get_error(), NULL
);
804 #ifdef SIGN_HAVE_ED25519
805 case KEYFMT_ED25519_BARE
:
806 if (!(verify_ctx
->key
= EVP_PKEY_new_raw_public_key(EVP_PKEY_ED25519
, NULL
,
808 ret
= US
ERR_error_string(ERR_get_error(), NULL
);
812 ret
= US
"pubkey format not handled";
822 /* verify signature (of hash, except Ed25519 where of-data)
823 (given pubkey & alleged sig)
824 Return: NULL for success, or an error string */
827 exim_dkim_verify(ev_ctx
* verify_ctx
, hashmethod hash
, blob
* data
, blob
* sig
)
833 case HASH_NULL
: md
= NULL
; break;
834 case HASH_SHA1
: md
= EVP_sha1(); break;
835 case HASH_SHA2_256
: md
= EVP_sha256(); break;
836 case HASH_SHA2_512
: md
= EVP_sha512(); break;
837 default: return US
"nonhandled hash type";
840 #ifdef SIGN_HAVE_ED25519
845 if ( (ctx
= EVP_MD_CTX_new())
846 && EVP_DigestVerifyInit(ctx
, NULL
, md
, NULL
, verify_ctx
->key
) > 0
847 && EVP_DigestVerify(ctx
, sig
->data
, sig
->len
, data
->data
, data
->len
) > 0
849 { EVP_MD_CTX_free(ctx
); return NULL
; }
851 if (ctx
) EVP_MD_CTX_free(ctx
);
858 if ( (ctx
= EVP_PKEY_CTX_new(verify_ctx
->key
, NULL
))
859 && EVP_PKEY_verify_init(ctx
) > 0
860 && EVP_PKEY_CTX_set_rsa_padding(ctx
, RSA_PKCS1_PADDING
) > 0
861 && EVP_PKEY_CTX_set_signature_md(ctx
, md
) > 0
862 && EVP_PKEY_verify(ctx
, sig
->data
, sig
->len
,
863 data
->data
, data
->len
) == 1
865 { EVP_PKEY_CTX_free(ctx
); return NULL
; }
867 if (ctx
) EVP_PKEY_CTX_free(ctx
);
869 return US
ERR_error_string(ERR_get_error(), NULL
);
875 /******************************************************************************/
877 #endif /*DISABLE_DKIM*/
878 #endif /*MACRO_PREDEF*/