+++ /dev/null
-/*
- * PDKIM - a RFC4871 (DKIM) implementation
- *
- * Copyright (C) 2016 Exim maintainers
- *
- * RSA signing/verification interface
- */
-
-#include "../exim.h"
-
-#ifndef DISABLE_DKIM /* entire file */
-
-#ifndef SUPPORT_TLS
-# error Need SUPPORT_TLS for DKIM
-#endif
-
-#include "crypt_ver.h"
-#include "rsa.h"
-
-
-/******************************************************************************/
-#ifdef RSA_GNUTLS
-
-void
-exim_rsa_init(void)
-{
-}
-
-
-/* accumulate data (gnutls-only). String to be appended must be nul-terminated. */
-blob *
-exim_rsa_data_append(blob * b, int * alloc, uschar * s)
-{
-int len = b->len;
-b->data = string_append(b->data, alloc, &len, 1, s);
-b->len = len;
-return b;
-}
-
-
-
-/* import private key from PEM string in memory.
-Return: NULL for success, or an error string */
-
-const uschar *
-exim_rsa_signing_init(uschar * privkey_pem, es_ctx * sign_ctx)
-{
-gnutls_datum_t k;
-int rc;
-
-k.data = privkey_pem;
-k.size = strlen(privkey_pem);
-
-if ( (rc = gnutls_x509_privkey_init(&sign_ctx->rsa)) != GNUTLS_E_SUCCESS
- /*|| (rc = gnutls_x509_privkey_import(sign_ctx->rsa, &k,
- GNUTLS_X509_FMT_PEM)) != GNUTLS_E_SUCCESS */
- )
- return gnutls_strerror(rc);
-
-if ( /* (rc = gnutls_x509_privkey_init(&sign_ctx->rsa)) != GNUTLS_E_SUCCESS
- ||*/ (rc = gnutls_x509_privkey_import(sign_ctx->rsa, &k,
- GNUTLS_X509_FMT_PEM)) != GNUTLS_E_SUCCESS
- )
- return gnutls_strerror(rc);
-
-return NULL;
-}
-
-
-
-/* allocate mem for signature (when signing) */
-/* sign data (gnutls_only)
-OR
-sign hash.
-
-Return: NULL for success, or an error string */
-
-const uschar *
-exim_rsa_sign(es_ctx * sign_ctx, BOOL is_sha1, blob * data, blob * sig)
-{
-gnutls_datum_t k;
-size_t sigsize = 0;
-int rc;
-const uschar * ret = NULL;
-
-/* Allocate mem for signature */
-k.data = data->data;
-k.size = data->len;
-(void) gnutls_x509_privkey_sign_data(sign_ctx->rsa,
- is_sha1 ? GNUTLS_DIG_SHA1 : GNUTLS_DIG_SHA256,
- 0, &k, NULL, &sigsize);
-
-sig->data = store_get(sigsize);
-sig->len = sigsize;
-
-/* Do signing */
-if ((rc = gnutls_x509_privkey_sign_data(sign_ctx->rsa,
- is_sha1 ? GNUTLS_DIG_SHA1 : GNUTLS_DIG_SHA256,
- 0, &k, sig->data, &sigsize)) != GNUTLS_E_SUCCESS
- )
- ret = gnutls_strerror(rc);
-
-gnutls_x509_privkey_deinit(sign_ctx->rsa);
-return ret;
-}
-
-
-
-/* import public key (from DER in memory)
-Return: NULL for success, or an error string */
-
-const uschar *
-exim_rsa_verify_init(blob * pubkey_der, ev_ctx * verify_ctx)
-{
-gnutls_datum_t k;
-int rc;
-const uschar * ret = NULL;
-
-gnutls_pubkey_init(&verify_ctx->rsa);
-
-k.data = pubkey_der->data;
-k.size = pubkey_der->len;
-
-if ((rc = gnutls_pubkey_import(verify_ctx->rsa, &k, GNUTLS_X509_FMT_DER))
- != GNUTLS_E_SUCCESS)
- ret = gnutls_strerror(rc);
-return ret;
-}
-
-
-/* verify signature (of hash) (given pubkey & alleged sig)
-Return: NULL for success, or an error string */
-
-const uschar *
-exim_rsa_verify(ev_ctx * verify_ctx, BOOL is_sha1, blob * data_hash, blob * sig)
-{
-gnutls_datum_t k, s;
-int rc;
-const uschar * ret = NULL;
-
-k.data = data_hash->data;
-k.size = data_hash->len;
-s.data = sig->data;
-s.size = sig->len;
-if ((rc = gnutls_pubkey_verify_hash2(verify_ctx->rsa,
- is_sha1 ? GNUTLS_SIGN_RSA_SHA1 : GNUTLS_SIGN_RSA_SHA256,
- 0, &k, &s)) < 0)
- ret = gnutls_strerror(rc);
-
-gnutls_pubkey_deinit(verify_ctx->rsa);
-return ret;
-}
-
-
-
-
-#elif defined(RSA_GCRYPT)
-/******************************************************************************/
-
-
-/* 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;
-
-/* 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_rsa_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. */
-
-blob *
-exim_rsa_data_append(blob * b, int * alloc, uschar * s)
-{
-return b; /*dummy*/
-}
-
-
-
-/* import private key from PEM string in memory.
-Return: NULL for success, or an error string */
-
-const uschar *
-exim_rsa_signing_init(uschar * privkey_pem, es_ctx * sign_ctx)
-{
-uschar * s1, * s2;
-blob der;
-long alen;
-int rc;
-
-/*
- * 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
- */
-
-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;
-
-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);
- }
-return NULL;
-
-asn_err: return US asn1_strerror(rc);
-}
-
-
-
-/* allocate mem for signature (when signing) */
-/* sign data (gnutls_only)
-OR
-sign hash.
-
-Return: NULL for success, or an error string */
-
-const uschar *
-exim_rsa_sign(es_ctx * sign_ctx, BOOL is_sha1, blob * data, blob * sig)
-{
-gcry_sexp_t s_hash = NULL, s_key = NULL, s_sig = NULL;
-gcry_mpi_t m_sig;
-uschar * errstr;
-gcry_error_t gerr;
-
-#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,
- is_sha1
- ? "(data(flags pkcs1)(hash sha1 %b))"
- : "(data(flags pkcs1)(hash sha256 %b))",
- (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);
-
-DEBUG(D_acl)
- {
- uschar * s;
- gcry_mpi_aprint (GCRYMPI_FMT_HEX, &s, NULL, m_sig);
- debug_printf_indent(" SG: %s\n", s);
- }
-
-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 DER in memory)
-Return: NULL for success, or an error string */
-
-const uschar *
-exim_rsa_verify_init(blob * pubkey_der, 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";
-
-/*
-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_der, 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_der, ASN1_CLASS_STRUCTURED, ASN1_TAG_SEQUENCE, &alen))
- != ASN1_SUCCESS) goto asn_err;
-pubkey_der->data += alen; pubkey_der->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_der, 0, ASN1_TAG_BIT_STRING, &alen)) != ASN1_SUCCESS)
- goto asn_err;
-pubkey_der->len = alen;
-pubkey_der->data++; pubkey_der->len--;
-
-/* sequence; just move past the header */
-DEBUG(D_acl) stage = US"S3";
-if ((rc = as_tag(pubkey_der, 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_der, &verify_ctx->n))
- || (errstr = as_mpi(pubkey_der, &verify_ctx->e))
- )
- return errstr;
-
-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);
- }
-
-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) (given pubkey & alleged sig)
-Return: NULL for success, or an error string */
-
-const uschar *
-exim_rsa_verify(ev_ctx * verify_ctx, BOOL is_sha1, blob * data_hash, blob * sig)
-{
-/*
-cf. libgnutls 2.8.5 _wrap_gcry_pk_verify()
-*/
-gcry_mpi_t m_sig;
-gcry_sexp_t s_sig = NULL, s_hash = NULL, s_pkey = NULL;
-gcry_error_t gerr;
-uschar * stage;
-
-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,
- is_sha1
- ? "(data(flags pkcs1)(hash sha1 %b))"
- : "(data(flags pkcs1)(hash sha256 %b))",
- (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(RSA_OPENSSL)
-/******************************************************************************/
-
-void
-exim_rsa_init(void)
-{
-}
-
-
-/* accumulate data (gnutls-only) */
-blob *
-exim_rsa_data_append(blob * b, int * alloc, uschar * s)
-{
-return b; /*dummy*/
-}
-
-
-/* import private key from PEM string in memory.
-Return: NULL for success, or an error string */
-
-const uschar *
-exim_rsa_signing_init(uschar * privkey_pem, es_ctx * sign_ctx)
-{
-uschar * p, * q;
-int len;
-
-/* Convert PEM to DER */
-if ( !(p = Ustrstr(privkey_pem, "-----BEGIN RSA PRIVATE KEY-----"))
- || !(q = Ustrstr(p+=31, "-----END RSA PRIVATE KEY-----"))
- )
- return US"Bad PEM wrapping";
-
-*q = '\0';
-if ((len = b64decode(p, &p)) < 0)
- return US"b64decode failed";
-
-if (!(sign_ctx->rsa = d2i_RSAPrivateKey(NULL, CUSS &p, len)))
- {
- char ssl_errstring[256];
- ERR_load_crypto_strings(); /*XXX move to a startup routine */
- ERR_error_string(ERR_get_error(), ssl_errstring);
- return string_copy(US ssl_errstring);
- }
-
-return NULL;
-}
-
-
-
-/* allocate mem for signature (when signing) */
-/* sign data (gnutls_only)
-OR
-sign hash.
-
-Return: NULL for success, or an error string */
-
-const uschar *
-exim_rsa_sign(es_ctx * sign_ctx, BOOL is_sha1, blob * data, blob * sig)
-{
-uint len;
-const uschar * ret = NULL;
-
-/* Allocate mem for signature */
-len = RSA_size(sign_ctx->rsa);
-sig->data = store_get(len);
-sig->len = len;
-
-/* Do signing */
-if (RSA_sign(is_sha1 ? NID_sha1 : NID_sha256,
- CUS data->data, data->len,
- US sig->data, &len, sign_ctx->rsa) != 1)
- {
- char ssl_errstring[256];
- ERR_load_crypto_strings(); /*XXX move to a startup routine */
- ERR_error_string(ERR_get_error(), ssl_errstring);
- ret = string_copy(US ssl_errstring);
- }
-
-RSA_free(sign_ctx->rsa);
-return ret;;
-}
-
-
-
-/* import public key (from DER in memory)
-Return: nULL for success, or an error string */
-
-const uschar *
-exim_rsa_verify_init(blob * pubkey_der, ev_ctx * verify_ctx)
-{
-const uschar * p = CUS pubkey_der->data;
-const uschar * ret = NULL;
-
-if (!(verify_ctx->rsa = d2i_RSA_PUBKEY(NULL, &p, (long) pubkey_der->len)))
- {
- char ssl_errstring[256];
- ERR_load_crypto_strings(); /*XXX move to a startup routine */
- ERR_error_string(ERR_get_error(), ssl_errstring);
- ret = string_copy(CUS ssl_errstring);
- }
-return ret;
-}
-
-
-
-
-/* verify signature (of hash) (given pubkey & alleged sig)
-Return: NULL for success, or an error string */
-
-const uschar *
-exim_rsa_verify(ev_ctx * verify_ctx, BOOL is_sha1, blob * data_hash, blob * sig)
-{
-const uschar * ret = NULL;
-
-if (RSA_verify(is_sha1 ? NID_sha1 : NID_sha256,
- CUS data_hash->data, data_hash->len,
- US sig->data, (uint) sig->len, verify_ctx->rsa) != 1)
- {
- char ssl_errstring[256];
- ERR_load_crypto_strings(); /*XXX move to a startup routine */
- ERR_error_string(ERR_get_error(), ssl_errstring);
- ret = string_copy(US ssl_errstring);
- }
-return ret;
-}
-
-
-#endif
-/******************************************************************************/
-
-#endif /*DISABLE_DKIM*/
-/* End of File */
HCoop / hcoop / debian / exim4.git / blobdiff