-/*
- * PDKIM - a RFC4871 (DKIM) implementation
- *
- * Copyright (C) 1995 - 2018 Exim maintainers
- *
- * signing/verification interface
- */
-
-#include "../exim.h"
-#include "crypt_ver.h"
-#include "signing.h"
-
-
-#ifdef MACRO_PREDEF
-# include "../macro_predef.h"
-
-void
-features_crypto(void)
-{
-# ifdef SIGN_HAVE_ED25519
- builtin_macro_create(US"_CRYPTO_SIGN_ED25519");
-# endif
-# ifdef EXIM_HAVE_SHA3
- builtin_macro_create(US"_CRYPTO_HASH_SHA3");
-# endif
-}
-#else
-
-#ifndef DISABLE_DKIM /* rest of file */
-
-#ifdef DISABLE_TLS
-# error Must no DISABLE_TLS, for DKIM
-#endif
-
-
-/******************************************************************************/
-#ifdef SIGN_GNUTLS
-# define EXIM_GNUTLS_LIBRARY_LOG_LEVEL 3
-
-
-/* Logging function which can be registered with
- * gnutls_global_set_log_function()
- * gnutls_global_set_log_level() 0..9
- */
-#if EXIM_GNUTLS_LIBRARY_LOG_LEVEL >= 0
-static void
-exim_gnutls_logger_cb(int level, const char *message)
-{
-size_t len = strlen(message);
-if (len < 1)
- {
- DEBUG(D_tls) debug_printf("GnuTLS<%d> empty debug message\n", level);
- return;
- }
-DEBUG(D_tls) debug_printf("GnuTLS<%d>: %s%s", level, message,
- message[len-1] == '\n' ? "" : "\n");
-}
-#endif
-
-
-
-void
-exim_dkim_init(void)
-{
-#if EXIM_GNUTLS_LIBRARY_LOG_LEVEL >= 0
-DEBUG(D_tls)
- {
- gnutls_global_set_log_function(exim_gnutls_logger_cb);
- /* arbitrarily chosen level; bump upto 9 for more */
- gnutls_global_set_log_level(EXIM_GNUTLS_LIBRARY_LOG_LEVEL);
- }
-#endif
-}
-
-
-/* accumulate data (gnutls-only). String to be appended must be nul-terminated. */
-gstring *
-exim_dkim_data_append(gstring * g, uschar * s)
-{
-return string_cat(g, s);
-}
-
-
-
-/* import private key from PEM string in memory.
-Return: NULL for success, or an error string */
-
-const uschar *
-exim_dkim_signing_init(const uschar * privkey_pem, es_ctx * sign_ctx)
-{
-gnutls_datum_t k = { .data = (void *)privkey_pem, .size = Ustrlen(privkey_pem) };
-gnutls_x509_privkey_t x509_key;
-const uschar * where;
-int rc;
-
-if ( (where = US"internal init", rc = gnutls_x509_privkey_init(&x509_key))
- || (rc = gnutls_privkey_init(&sign_ctx->key))
- || (where = US"privkey PEM-block import",
- rc = gnutls_x509_privkey_import(x509_key, &k, GNUTLS_X509_FMT_PEM))
- || (where = US"internal privkey transfer",
- rc = gnutls_privkey_import_x509(sign_ctx->key, x509_key, 0))
- )
- return string_sprintf("%s: %s", where, gnutls_strerror(rc));
-
-switch (rc = gnutls_privkey_get_pk_algorithm(sign_ctx->key, NULL))
- {
- case GNUTLS_PK_RSA: sign_ctx->keytype = KEYTYPE_RSA; break;
-#ifdef SIGN_HAVE_ED25519
- case GNUTLS_PK_EDDSA_ED25519: sign_ctx->keytype = KEYTYPE_ED25519; break;
-#endif
- default: return rc < 0
- ? CUS gnutls_strerror(rc)
- : string_sprintf("Unhandled key type: %d '%s'", rc, gnutls_pk_get_name(rc));
- }
-
-return NULL;
-}
-
-
-
-/* allocate mem for signature (when signing) */
-/* hash & sign data. No way to do incremental.
-
-Return: NULL for success, or an error string */
-
-const uschar *
-exim_dkim_sign(es_ctx * sign_ctx, hashmethod hash, blob * data, blob * sig)
-{
-gnutls_datum_t k_data = { .data = data->data, .size = data->len };
-gnutls_digest_algorithm_t dig;
-gnutls_datum_t k_sig;
-int rc;
-
-switch (hash)
- {
- case HASH_SHA1: dig = GNUTLS_DIG_SHA1; break;
- case HASH_SHA2_256: dig = GNUTLS_DIG_SHA256; break;
- case HASH_SHA2_512: dig = GNUTLS_DIG_SHA512; break;
- default: return US"nonhandled hash type";
- }
-
-if ((rc = gnutls_privkey_sign_data(sign_ctx->key, dig, 0, &k_data, &k_sig)))
- return CUS gnutls_strerror(rc);
-
-/* Don't care about deinit for the key; shortlived process */
-
-sig->data = k_sig.data;
-sig->len = k_sig.size;
-return NULL;
-}
-
-
-
-/* import public key (from blob in memory)
-Return: NULL for success, or an error string */
-
-const uschar *
-exim_dkim_verify_init(blob * pubkey, keyformat fmt, ev_ctx * verify_ctx)
-{
-gnutls_datum_t k;
-int rc;
-const uschar * ret = NULL;
-
-gnutls_pubkey_init(&verify_ctx->key);
-k.data = pubkey->data;
-k.size = pubkey->len;
-
-switch(fmt)
- {
- case KEYFMT_DER:
- if ((rc = gnutls_pubkey_import(verify_ctx->key, &k, GNUTLS_X509_FMT_DER)))
- ret = US gnutls_strerror(rc);
- break;
-#ifdef SIGN_HAVE_ED25519
- case KEYFMT_ED25519_BARE:
- if ((rc = gnutls_pubkey_import_ecc_raw(verify_ctx->key,
- GNUTLS_ECC_CURVE_ED25519, &k, NULL)))
- ret = US gnutls_strerror(rc);
- break;
-#endif
- default:
- ret = US"pubkey format not handled";
- break;
- }
-return ret;
-}
-
-
-/* verify signature (of hash if RSA sig, of data if EC sig. No way to do incremental)
-(given pubkey & alleged sig)
-Return: NULL for success, or an error string */
-
-const uschar *
-exim_dkim_verify(ev_ctx * verify_ctx, hashmethod hash, blob * data_hash, blob * sig)
-{
-gnutls_datum_t k = { .data = data_hash->data, .size = data_hash->len };
-gnutls_datum_t s = { .data = sig->data, .size = sig->len };
-int rc;
-const uschar * ret = NULL;
-
-#ifdef SIGN_HAVE_ED25519
-if (verify_ctx->keytype == KEYTYPE_ED25519)
- {
- if ((rc = gnutls_pubkey_verify_data2(verify_ctx->key,
- GNUTLS_SIGN_EDDSA_ED25519, 0, &k, &s)) < 0)
- ret = US gnutls_strerror(rc);
- }
-else
-#endif
- {
- gnutls_sign_algorithm_t algo;
- switch (hash)
- {
- case HASH_SHA1: algo = GNUTLS_SIGN_RSA_SHA1; break;
- case HASH_SHA2_256: algo = GNUTLS_SIGN_RSA_SHA256; break;
- case HASH_SHA2_512: algo = GNUTLS_SIGN_RSA_SHA512; break;
- default: return US"nonhandled hash type";
- }
-
- if ((rc = gnutls_pubkey_verify_hash2(verify_ctx->key, algo, 0, &k, &s)) < 0)
- ret = US gnutls_strerror(rc);
- }
-
-gnutls_pubkey_deinit(verify_ctx->key);
-return ret;
-}
-
-
-
-
-#elif defined(SIGN_GCRYPT)
-/******************************************************************************/
-/* This variant is used under pre-3.0.0 GnuTLS. Only rsa-sha1 and rsa-sha256 */
-
-
-/* Internal service routine:
-Read and move past an asn.1 header, checking class & tag,
-optionally returning the data-length */
-
-static int
-as_tag(blob * der, uschar req_cls, long req_tag, long * alen)
-{
-int rc;
-uschar tag_class;
-int taglen;
-long tag, len;
-
-debug_printf_indent("as_tag: %02x %02x %02x %02x\n",
- der->data[0], der->data[1], der->data[2], der->data[3]);
-
-if ((rc = asn1_get_tag_der(der->data++, der->len--, &tag_class, &taglen, &tag))
- != ASN1_SUCCESS)
- return rc;
-
-if (tag_class != req_cls || tag != req_tag) return ASN1_ELEMENT_NOT_FOUND;
-
-if ((len = asn1_get_length_der(der->data, der->len, &taglen)) < 0)
- return ASN1_DER_ERROR;
-if (alen) *alen = len;
-
-/* debug_printf_indent("as_tag: tlen %d dlen %d\n", taglen, (int)len); */
-
-der->data += taglen;
-der->len -= taglen;
-return rc;
-}
-
-/* Internal service routine:
-Read and move over an asn.1 integer, setting an MPI to the value
-*/
-
-static uschar *
-as_mpi(blob * der, gcry_mpi_t * mpi)
-{
-long alen;
-int rc;
-gcry_error_t gerr;
-
-debug_printf_indent("%s\n", __FUNCTION__);
-
-/* integer; move past the header */
-if ((rc = as_tag(der, 0, ASN1_TAG_INTEGER, &alen)) != ASN1_SUCCESS)
- return US asn1_strerror(rc);
-
-/* read to an MPI */
-if ((gerr = gcry_mpi_scan(mpi, GCRYMPI_FMT_STD, der->data, alen, NULL)))
- return US gcry_strerror(gerr);
-
-/* move over the data */
-der->data += alen; der->len -= alen;
-return NULL;
-}
-
-
-
-void
-exim_dkim_init(void)
-{
-/* Version check should be the very first call because it
-makes sure that important subsystems are initialized. */
-if (!gcry_check_version (GCRYPT_VERSION))
- {
- fputs ("libgcrypt version mismatch\n", stderr);
- exit (2);
- }
-
-/* We don't want to see any warnings, e.g. because we have not yet
-parsed program options which might be used to suppress such
-warnings. */
-gcry_control (GCRYCTL_SUSPEND_SECMEM_WARN);
-
-/* ... If required, other initialization goes here. Note that the
-process might still be running with increased privileges and that
-the secure memory has not been initialized. */
-
-/* Allocate a pool of 16k secure memory. This make the secure memory
-available and also drops privileges where needed. */
-gcry_control (GCRYCTL_INIT_SECMEM, 16384, 0);
-
-/* It is now okay to let Libgcrypt complain when there was/is
-a problem with the secure memory. */
-gcry_control (GCRYCTL_RESUME_SECMEM_WARN);
-
-/* ... If required, other initialization goes here. */
-
-/* Tell Libgcrypt that initialization has completed. */
-gcry_control (GCRYCTL_INITIALIZATION_FINISHED, 0);
-
-return;
-}
-
-
-
-
-/* Accumulate data (gnutls-only).
-String to be appended must be nul-terminated. */
-
-gstring *
-exim_dkim_data_append(gstring * g, uschar * s)
-{
-return g; /*dummy*/
-}
-
-
-
-/* import private key from PEM string in memory.
-Only handles RSA keys.
-Return: NULL for success, or an error string */
-
-const uschar *
-exim_dkim_signing_init(const uschar * privkey_pem, es_ctx * sign_ctx)
-{
-uschar * s1, * s2;
-blob der;
-long alen;
-int rc;
-
-/*XXX will need extension to _spot_ as well as handle a
-non-RSA key? I think...
-So... this is not a PrivateKeyInfo - which would have a field
-identifying the keytype - PrivateKeyAlgorithmIdentifier -
-but a plain RSAPrivateKey (wrapped in PEM-headers. Can we
-use those as a type tag? What forms are there? "BEGIN EC PRIVATE KEY" (cf. ec(1ssl))
-
-How does OpenSSL PEM_read_bio_PrivateKey() deal with it?
-gnutls_x509_privkey_import() ?
-*/
-
-/*
- * RSAPrivateKey ::= SEQUENCE
- * version Version,
- * modulus INTEGER, -- n
- * publicExponent INTEGER, -- e
- * privateExponent INTEGER, -- d
- * prime1 INTEGER, -- p
- * prime2 INTEGER, -- q
- * exponent1 INTEGER, -- d mod (p-1)
- * exponent2 INTEGER, -- d mod (q-1)
- * coefficient INTEGER, -- (inverse of q) mod p
- * otherPrimeInfos OtherPrimeInfos OPTIONAL
-
- * ECPrivateKey ::= SEQUENCE {
- * version INTEGER { ecPrivkeyVer1(1) } (ecPrivkeyVer1),
- * privateKey OCTET STRING,
- * parameters [0] ECParameters {{ NamedCurve }} OPTIONAL,
- * publicKey [1] BIT STRING OPTIONAL
- * }
- * Hmm, only 1 useful item, and not even an integer? Wonder how we might use it...
-
-- actually, gnutls_x509_privkey_import() appears to require a curve name parameter
- value for that is an OID? a local-only integer (it's an enum in GnuTLS)?
-
-
-Useful cmds:
- ssh-keygen -t ecdsa -f foo.privkey
- ssh-keygen -t ecdsa -b384 -f foo.privkey
- ssh-keygen -t ecdsa -b521 -f foo.privkey
- ssh-keygen -t ed25519 -f foo.privkey
-
- < foo openssl pkcs8 -in /dev/stdin -inform PEM -nocrypt -topk8 -outform DER | od -x
-
- openssl asn1parse -in foo -inform PEM -dump
- openssl asn1parse -in foo -inform PEM -dump -stroffset 24 (??)
-(not good for ed25519)
-
- */
-
-if ( !(s1 = Ustrstr(CS privkey_pem, "-----BEGIN RSA PRIVATE KEY-----"))
- || !(s2 = Ustrstr(CS (s1+=31), "-----END RSA PRIVATE KEY-----" ))
- )
- return US"Bad PEM wrapper";
-
-*s2 = '\0';
-
-if ((der.len = b64decode(s1, &der.data)) < 0)
- return US"Bad PEM-DER b64 decode";
-
-/* untangle asn.1 */
-
-/* sequence; just move past the header */
-if ((rc = as_tag(&der, ASN1_CLASS_STRUCTURED, ASN1_TAG_SEQUENCE, NULL))
- != ASN1_SUCCESS) goto asn_err;
-
-/* integer version; move past the header, check is zero */
-if ((rc = as_tag(&der, 0, ASN1_TAG_INTEGER, &alen)) != ASN1_SUCCESS)
- goto asn_err;
-if (alen != 1 || *der.data != 0)
- return US"Bad version number";
-der.data++; der.len--;
-
-if ( (s1 = as_mpi(&der, &sign_ctx->n))
- || (s1 = as_mpi(&der, &sign_ctx->e))
- || (s1 = as_mpi(&der, &sign_ctx->d))
- || (s1 = as_mpi(&der, &sign_ctx->p))
- || (s1 = as_mpi(&der, &sign_ctx->q))
- || (s1 = as_mpi(&der, &sign_ctx->dp))
- || (s1 = as_mpi(&der, &sign_ctx->dq))
- || (s1 = as_mpi(&der, &sign_ctx->qp))
- )
- return s1;
-
-#ifdef extreme_debug
-DEBUG(D_acl) debug_printf_indent("rsa_signing_init:\n");
- {
- uschar * s;
- gcry_mpi_aprint (GCRYMPI_FMT_HEX, &s, NULL, sign_ctx->n);
- debug_printf_indent(" N : %s\n", s);
- gcry_mpi_aprint (GCRYMPI_FMT_HEX, &s, NULL, sign_ctx->e);
- debug_printf_indent(" E : %s\n", s);
- gcry_mpi_aprint (GCRYMPI_FMT_HEX, &s, NULL, sign_ctx->d);
- debug_printf_indent(" D : %s\n", s);
- gcry_mpi_aprint (GCRYMPI_FMT_HEX, &s, NULL, sign_ctx->p);
- debug_printf_indent(" P : %s\n", s);
- gcry_mpi_aprint (GCRYMPI_FMT_HEX, &s, NULL, sign_ctx->q);
- debug_printf_indent(" Q : %s\n", s);
- gcry_mpi_aprint (GCRYMPI_FMT_HEX, &s, NULL, sign_ctx->dp);
- debug_printf_indent(" DP: %s\n", s);
- gcry_mpi_aprint (GCRYMPI_FMT_HEX, &s, NULL, sign_ctx->dq);
- debug_printf_indent(" DQ: %s\n", s);
- gcry_mpi_aprint (GCRYMPI_FMT_HEX, &s, NULL, sign_ctx->qp);
- debug_printf_indent(" QP: %s\n", s);
- }
-#endif
-
-sign_ctx->keytype = KEYTYPE_RSA;
-return NULL;
-
-asn_err: return US asn1_strerror(rc);
-}
-
-
-
-/* allocate mem for signature (when signing) */
-/* sign already-hashed data.
-
-Return: NULL for success, or an error string */
-
-const uschar *
-exim_dkim_sign(es_ctx * sign_ctx, hashmethod hash, blob * data, blob * sig)
-{
-char * sexp_hash;
-gcry_sexp_t s_hash = NULL, s_key = NULL, s_sig = NULL;
-gcry_mpi_t m_sig;
-uschar * errstr;
-gcry_error_t gerr;
-
-/*XXX will need extension for hash types (though, possibly, should
-be re-specced to not rehash but take an already-hashed value? Actually
-current impl looks WRONG - it _is_ given a hash so should not be
-re-hashing. Has this been tested?
-
-Will need extension for non-RSA sugning algos. */
-
-switch (hash)
- {
- case HASH_SHA1: sexp_hash = "(data(flags pkcs1)(hash sha1 %b))"; break;
- case HASH_SHA2_256: sexp_hash = "(data(flags pkcs1)(hash sha256 %b))"; break;
- default: return US"nonhandled hash type";
- }
-
-#define SIGSPACE 128
-sig->data = store_get(SIGSPACE);
-
-if (gcry_mpi_cmp (sign_ctx->p, sign_ctx->q) > 0)
- {
- gcry_mpi_swap (sign_ctx->p, sign_ctx->q);
- gcry_mpi_invm (sign_ctx->qp, sign_ctx->p, sign_ctx->q);
- }
-
-if ( (gerr = gcry_sexp_build (&s_key, NULL,
- "(private-key (rsa (n%m)(e%m)(d%m)(p%m)(q%m)(u%m)))",
- sign_ctx->n, sign_ctx->e,
- sign_ctx->d, sign_ctx->p,
- sign_ctx->q, sign_ctx->qp))
- || (gerr = gcry_sexp_build (&s_hash, NULL, sexp_hash,
- (int) data->len, CS data->data))
- || (gerr = gcry_pk_sign (&s_sig, s_hash, s_key))
- )
- return US gcry_strerror(gerr);
-
-/* gcry_sexp_dump(s_sig); */
-
-if ( !(s_sig = gcry_sexp_find_token(s_sig, "s", 0))
- )
- return US"no sig result";
-
-m_sig = gcry_sexp_nth_mpi(s_sig, 1, GCRYMPI_FMT_USG);
-
-#ifdef extreme_debug
-DEBUG(D_acl)
- {
- uschar * s;
- gcry_mpi_aprint (GCRYMPI_FMT_HEX, &s, NULL, m_sig);
- debug_printf_indent(" SG: %s\n", s);
- }
-#endif
-
-gerr = gcry_mpi_print(GCRYMPI_FMT_USG, sig->data, SIGSPACE, &sig->len, m_sig);
-if (gerr)
- {
- debug_printf_indent("signature conversion from MPI to buffer failed\n");
- return US gcry_strerror(gerr);
- }
-#undef SIGSPACE
-
-return NULL;
-}
-
-
-/* import public key (from blob in memory)
-Return: NULL for success, or an error string */
-
-const uschar *
-exim_dkim_verify_init(blob * pubkey, keyformat fmt, ev_ctx * verify_ctx)
-{
-/*
-in code sequence per b81207d2bfa92 rsa_parse_public_key() and asn1_get_mpi()
-*/
-uschar tag_class;
-int taglen;
-long alen;
-int rc;
-uschar * errstr;
-gcry_error_t gerr;
-uschar * stage = US"S1";
-
-if (fmt != KEYFMT_DER) return US"pubkey format not handled";
-
-/*
-sequence
- sequence
- OBJECT:rsaEncryption
- NULL
- BIT STRING:RSAPublicKey
- sequence
- INTEGER:Public modulus
- INTEGER:Public exponent
-
-openssl rsa -in aux-fixed/dkim/dkim.private -pubout -outform DER | od -t x1 | head;
-openssl rsa -in aux-fixed/dkim/dkim.private -pubout | openssl asn1parse -dump;
-openssl rsa -in aux-fixed/dkim/dkim.private -pubout | openssl asn1parse -dump -offset 22;
-*/
-
-/* sequence; just move past the header */
-if ((rc = as_tag(pubkey, ASN1_CLASS_STRUCTURED, ASN1_TAG_SEQUENCE, NULL))
- != ASN1_SUCCESS) goto asn_err;
-
-/* sequence; skip the entire thing */
-DEBUG(D_acl) stage = US"S2";
-if ((rc = as_tag(pubkey, ASN1_CLASS_STRUCTURED, ASN1_TAG_SEQUENCE, &alen))
- != ASN1_SUCCESS) goto asn_err;
-pubkey->data += alen; pubkey->len -= alen;
-
-
-/* bitstring: limit range to size of bitstring;
-move over header + content wrapper */
-DEBUG(D_acl) stage = US"BS";
-if ((rc = as_tag(pubkey, 0, ASN1_TAG_BIT_STRING, &alen)) != ASN1_SUCCESS)
- goto asn_err;
-pubkey->len = alen;
-pubkey->data++; pubkey->len--;
-
-/* sequence; just move past the header */
-DEBUG(D_acl) stage = US"S3";
-if ((rc = as_tag(pubkey, ASN1_CLASS_STRUCTURED, ASN1_TAG_SEQUENCE, NULL))
- != ASN1_SUCCESS) goto asn_err;
-
-/* read two integers */
-DEBUG(D_acl) stage = US"MPI";
-if ( (errstr = as_mpi(pubkey, &verify_ctx->n))
- || (errstr = as_mpi(pubkey, &verify_ctx->e))
- )
- return errstr;
-
-#ifdef extreme_debug
-DEBUG(D_acl) debug_printf_indent("rsa_verify_init:\n");
- {
- uschar * s;
- gcry_mpi_aprint (GCRYMPI_FMT_HEX, &s, NULL, verify_ctx->n);
- debug_printf_indent(" N : %s\n", s);
- gcry_mpi_aprint (GCRYMPI_FMT_HEX, &s, NULL, verify_ctx->e);
- debug_printf_indent(" E : %s\n", s);
- }
-
-#endif
-return NULL;
-
-asn_err:
-DEBUG(D_acl) return string_sprintf("%s: %s", stage, asn1_strerror(rc));
- return US asn1_strerror(rc);
-}
-
-
-/* verify signature (of hash)
-XXX though we appear to be doing a hash, too!
-(given pubkey & alleged sig)
-Return: NULL for success, or an error string */
-
-const uschar *
-exim_dkim_verify(ev_ctx * verify_ctx, hashmethod hash, blob * data_hash, blob * sig)
-{
-/*
-cf. libgnutls 2.8.5 _wrap_gcry_pk_verify()
-*/
-char * sexp_hash;
-gcry_mpi_t m_sig;
-gcry_sexp_t s_sig = NULL, s_hash = NULL, s_pkey = NULL;
-gcry_error_t gerr;
-uschar * stage;
-
-/*XXX needs extension for SHA512 */
-switch (hash)
- {
- case HASH_SHA1: sexp_hash = "(data(flags pkcs1)(hash sha1 %b))"; break;
- case HASH_SHA2_256: sexp_hash = "(data(flags pkcs1)(hash sha256 %b))"; break;
- default: return US"nonhandled hash type";
- }
-
-if ( (stage = US"pkey sexp build",
- gerr = gcry_sexp_build (&s_pkey, NULL, "(public-key(rsa(n%m)(e%m)))",
- verify_ctx->n, verify_ctx->e))
- || (stage = US"data sexp build",
- gerr = gcry_sexp_build (&s_hash, NULL, sexp_hash,
- (int) data_hash->len, CS data_hash->data))
- || (stage = US"sig mpi scan",
- gerr = gcry_mpi_scan(&m_sig, GCRYMPI_FMT_USG, sig->data, sig->len, NULL))
- || (stage = US"sig sexp build",
- gerr = gcry_sexp_build (&s_sig, NULL, "(sig-val(rsa(s%m)))", m_sig))
- || (stage = US"verify",
- gerr = gcry_pk_verify (s_sig, s_hash, s_pkey))
- )
- {
- DEBUG(D_acl) debug_printf_indent("verify: error in stage '%s'\n", stage);
- return US gcry_strerror(gerr);
- }
-
-if (s_sig) gcry_sexp_release (s_sig);
-if (s_hash) gcry_sexp_release (s_hash);
-if (s_pkey) gcry_sexp_release (s_pkey);
-gcry_mpi_release (m_sig);
-gcry_mpi_release (verify_ctx->n);
-gcry_mpi_release (verify_ctx->e);
-
-return NULL;
-}
-
-
-
-
-#elif defined(SIGN_OPENSSL)
-/******************************************************************************/
-
-void
-exim_dkim_init(void)
-{
-ERR_load_crypto_strings();
-}
-
-
-/* accumulate data (was gnutls-only but now needed for OpenSSL non-EC too
-because now using hash-and-sign interface) */
-gstring *
-exim_dkim_data_append(gstring * g, uschar * s)
-{
-return string_cat(g, s);
-}
-
-
-/* import private key from PEM string in memory.
-Return: NULL for success, or an error string */
-
-const uschar *
-exim_dkim_signing_init(const uschar * privkey_pem, es_ctx * sign_ctx)
-{
-BIO * bp = BIO_new_mem_buf(privkey_pem, -1);
-
-if (!(sign_ctx->key = PEM_read_bio_PrivateKey(bp, NULL, NULL, NULL)))
- return string_sprintf("privkey PEM-block import: %s",
- ERR_error_string(ERR_get_error(), NULL));
-
-sign_ctx->keytype =
-#ifdef SIGN_HAVE_ED25519
- EVP_PKEY_type(EVP_PKEY_id(sign_ctx->key)) == EVP_PKEY_ED25519
- ? KEYTYPE_ED25519 : KEYTYPE_RSA;
-#else
- KEYTYPE_RSA;
-#endif
-return NULL;
-}
-
-
-
-/* allocate mem for signature (when signing) */
-/* hash & sign data. Incremental not supported.
-
-Return: NULL for success with the signaature in the sig blob, or an error string */
-
-const uschar *
-exim_dkim_sign(es_ctx * sign_ctx, hashmethod hash, blob * data, blob * sig)
-{
-const EVP_MD * md;
-EVP_MD_CTX * ctx;
-size_t siglen;
-
-switch (hash)
- {
- case HASH_NULL: md = NULL; break; /* Ed25519 signing */
- case HASH_SHA1: md = EVP_sha1(); break;
- case HASH_SHA2_256: md = EVP_sha256(); break;
- case HASH_SHA2_512: md = EVP_sha512(); break;
- default: return US"nonhandled hash type";
- }
-
-#ifdef SIGN_HAVE_ED25519
-if ( (ctx = EVP_MD_CTX_new())
- && EVP_DigestSignInit(ctx, NULL, md, NULL, sign_ctx->key) > 0
- && EVP_DigestSign(ctx, NULL, &siglen, NULL, 0) > 0
- && (sig->data = store_get(siglen))
-
- /* Obtain the signature (slen could change here!) */
- && EVP_DigestSign(ctx, sig->data, &siglen, data->data, data->len) > 0
- )
- {
- EVP_MD_CTX_destroy(ctx);
- sig->len = siglen;
- return NULL;
- }
-#else
-/*XXX renamed to EVP_MD_CTX_new() in 1.1.0 */
-if ( (ctx = EVP_MD_CTX_create())
- && EVP_DigestSignInit(ctx, NULL, md, NULL, sign_ctx->key) > 0
- && EVP_DigestSignUpdate(ctx, data->data, data->len) > 0
- && EVP_DigestSignFinal(ctx, NULL, &siglen) > 0
- && (sig->data = store_get(siglen))
-
- /* Obtain the signature (slen could change here!) */
- && EVP_DigestSignFinal(ctx, sig->data, &siglen) > 0
- )
- {
- EVP_MD_CTX_destroy(ctx);
- sig->len = siglen;
- return NULL;
- }
-#endif
-
-if (ctx) EVP_MD_CTX_destroy(ctx);
-return US ERR_error_string(ERR_get_error(), NULL);
-}
-
-
-
-/* import public key (from blob in memory)
-Return: NULL for success, or an error string */
-
-const uschar *
-exim_dkim_verify_init(blob * pubkey, keyformat fmt, ev_ctx * verify_ctx)
-{
-const uschar * s = pubkey->data;
-uschar * ret = NULL;
-
-switch(fmt)
- {
- case KEYFMT_DER:
- /*XXX hmm, we never free this */
- if (!(verify_ctx->key = d2i_PUBKEY(NULL, &s, pubkey->len)))
- ret = US ERR_error_string(ERR_get_error(), NULL);
- break;
-#ifdef SIGN_HAVE_ED25519
- case KEYFMT_ED25519_BARE:
- if (!(verify_ctx->key = EVP_PKEY_new_raw_public_key(EVP_PKEY_ED25519, NULL,
- s, pubkey->len)))
- ret = US ERR_error_string(ERR_get_error(), NULL);
- break;
-#endif
- default:
- ret = US"pubkey format not handled";
- break;
- }
-
-return ret;
-}
-
-
-
-
-/* verify signature (of hash, except Ed25519 where of-data)
-(given pubkey & alleged sig)
-Return: NULL for success, or an error string */
-
-const uschar *
-exim_dkim_verify(ev_ctx * verify_ctx, hashmethod hash, blob * data, blob * sig)
-{
-const EVP_MD * md;
-
-switch (hash)
- {
- case HASH_NULL: md = NULL; break;
- case HASH_SHA1: md = EVP_sha1(); break;
- case HASH_SHA2_256: md = EVP_sha256(); break;
- case HASH_SHA2_512: md = EVP_sha512(); break;
- default: return US"nonhandled hash type";
- }
-
-#ifdef SIGN_HAVE_ED25519
-if (!md)
- {
- EVP_MD_CTX * ctx;
-
- if ((ctx = EVP_MD_CTX_new()))
- {
- if ( EVP_DigestVerifyInit(ctx, NULL, md, NULL, verify_ctx->key) > 0
- && EVP_DigestVerify(ctx, sig->data, sig->len, data->data, data->len) > 0
- )
- { EVP_MD_CTX_free(ctx); return NULL; }
- EVP_MD_CTX_free(ctx);
- }
- }
-else
-#endif
- {
- EVP_PKEY_CTX * ctx;
-
- if ((ctx = EVP_PKEY_CTX_new(verify_ctx->key, NULL)))
- {
- if ( EVP_PKEY_verify_init(ctx) > 0
- && EVP_PKEY_CTX_set_rsa_padding(ctx, RSA_PKCS1_PADDING) > 0
- && EVP_PKEY_CTX_set_signature_md(ctx, md) > 0
- && EVP_PKEY_verify(ctx, sig->data, sig->len,
- data->data, data->len) == 1
- )
- { EVP_PKEY_CTX_free(ctx); return NULL; }
- EVP_PKEY_CTX_free(ctx);
-
- DEBUG(D_tls)
- if (Ustrcmp(ERR_reason_error_string(ERR_peek_error()), "wrong signature length") == 0)
- debug_printf("sig len (from msg hdr): %d, expected (from dns pubkey) %d\n",
- (int) sig->len, EVP_PKEY_size(verify_ctx->key));
- }
- }
-
-return US ERR_error_string(ERR_get_error(), NULL);
-}
-
-
-
-#endif
-/******************************************************************************/
-
-#endif /*DISABLE_DKIM*/
-#endif /*MACRO_PREDEF*/
-/* End of File */
git://git.exim.org / exim.git / blobdiff