X-Git-Url: https://vcs.fsf.org/?a=blobdiff_plain;f=src%2Fsrc%2Fpdkim%2Frsa.c;h=950c617c78171b2561a4dc00ede001ca811fdf7b;hb=6e4aaa853615d40316858a5ca08da784350cb142;hp=726e65a51add0f0cdb996cd2143d7830c7884779;hpb=ac3ad4262e3fe4b6ca02532c706069251c32106e;p=exim.git diff --git a/src/src/pdkim/rsa.c b/src/src/pdkim/rsa.c index 726e65a51..950c617c7 100644 --- a/src/src/pdkim/rsa.c +++ b/src/src/pdkim/rsa.c @@ -1,823 +1,679 @@ /* - * The RSA public-key cryptosystem + * PDKIM - a RFC4871 (DKIM) implementation * - * Copyright (C) 2006-2010, Brainspark B.V. + * Copyright (C) 2016 Exim maintainers * - * This file is part of PolarSSL (http://www.polarssl.org) - * Lead Maintainer: Paul Bakker - * - * All rights reserved. - * - * This program is free software; you can redistribute it and/or modify - * it under the terms of the GNU General Public License as published by - * the Free Software Foundation; either version 2 of the License, or - * (at your option) any later version. - * - * This program is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - * GNU General Public License for more details. - * - * You should have received a copy of the GNU General Public License along - * with this program; if not, write to the Free Software Foundation, Inc., - * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. - */ -/* - * RSA was designed by Ron Rivest, Adi Shamir and Len Adleman. - * - * http://theory.lcs.mit.edu/~rivest/rsapaper.pdf - * http://www.cacr.math.uwaterloo.ca/hac/about/chap8.pdf + * RSA signing/verification interface */ -#include "polarssl/config.h" +#include "../exim.h" -#if defined(POLARSSL_RSA_C) +#ifndef DISABLE_DKIM /* entire file */ -#include "polarssl/rsa.h" +#ifndef SUPPORT_TLS +# error Need SUPPORT_TLS for DKIM +#endif -#include -#include -#include +#include "crypt_ver.h" +#include "rsa.h" -/* - * Initialize an RSA context - */ -void rsa_init( rsa_context *ctx, - int padding, - int hash_id ) -{ - memset( ctx, 0, sizeof( rsa_context ) ); - ctx->padding = padding; - ctx->hash_id = hash_id; +/******************************************************************************/ +#ifdef RSA_GNUTLS + +void +exim_rsa_init(void) +{ } -#if defined(POLARSSL_GENPRIME) -/* - * Generate an RSA keypair - */ -int rsa_gen_key( rsa_context *ctx, - int (*f_rng)(void *), - void *p_rng, - int nbits, int exponent ) +/* accumulate data (gnutls-only). String to be appended must be nul-terminated. */ +blob * +exim_rsa_data_append(blob * b, int * alloc, uschar * s) { - int ret; - mpi P1, Q1, H, G; +int len = b->len; +b->data = string_append(b->data, alloc, &len, 1, s); +b->len = len; +return b; +} - if( f_rng == NULL || nbits < 128 || exponent < 3 ) - return( POLARSSL_ERR_RSA_BAD_INPUT_DATA ); - mpi_init( &P1, &Q1, &H, &G, NULL ); - /* - * find primes P and Q with Q < P so that: - * GCD( E, (P-1)*(Q-1) ) == 1 - */ - MPI_CHK( mpi_lset( &ctx->E, exponent ) ); +/* import private key from PEM string in memory. +Return: NULL for success, or an error string */ - do - { - MPI_CHK( mpi_gen_prime( &ctx->P, ( nbits + 1 ) >> 1, 0, - f_rng, p_rng ) ); +const uschar * +exim_rsa_signing_init(uschar * privkey_pem, es_ctx * sign_ctx) +{ +gnutls_datum_t k; +int rc; - MPI_CHK( mpi_gen_prime( &ctx->Q, ( nbits + 1 ) >> 1, 0, - f_rng, p_rng ) ); +k.data = privkey_pem; +k.size = strlen(privkey_pem); - if( mpi_cmp_mpi( &ctx->P, &ctx->Q ) < 0 ) - mpi_swap( &ctx->P, &ctx->Q ); +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( mpi_cmp_mpi( &ctx->P, &ctx->Q ) == 0 ) - continue; +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); - MPI_CHK( mpi_mul_mpi( &ctx->N, &ctx->P, &ctx->Q ) ); - if( mpi_msb( &ctx->N ) != nbits ) - continue; +return NULL; +} - MPI_CHK( mpi_sub_int( &P1, &ctx->P, 1 ) ); - MPI_CHK( mpi_sub_int( &Q1, &ctx->Q, 1 ) ); - MPI_CHK( mpi_mul_mpi( &H, &P1, &Q1 ) ); - MPI_CHK( mpi_gcd( &G, &ctx->E, &H ) ); - } - while( mpi_cmp_int( &G, 1 ) != 0 ); - /* - * D = E^-1 mod ((P-1)*(Q-1)) - * DP = D mod (P - 1) - * DQ = D mod (Q - 1) - * QP = Q^-1 mod P - */ - MPI_CHK( mpi_inv_mod( &ctx->D , &ctx->E, &H ) ); - MPI_CHK( mpi_mod_mpi( &ctx->DP, &ctx->D, &P1 ) ); - MPI_CHK( mpi_mod_mpi( &ctx->DQ, &ctx->D, &Q1 ) ); - MPI_CHK( mpi_inv_mod( &ctx->QP, &ctx->Q, &ctx->P ) ); - ctx->len = ( mpi_msb( &ctx->N ) + 7 ) >> 3; +/* allocate mem for signature (when signing) */ +/* sign data (gnutls_only) +OR +sign hash. -cleanup: +Return: NULL for success, or an error string */ - mpi_free( &G, &H, &Q1, &P1, NULL ); +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; +} - if( ret != 0 ) - { - rsa_free( ctx ); - return( POLARSSL_ERR_RSA_KEY_GEN_FAILED | ret ); - } - return( 0 ); -} -#endif +/* import public key (from DER in memory) +Return: NULL for success, or an error string */ -/* - * Check a public RSA key - */ -int rsa_check_pubkey( const rsa_context *ctx ) +const uschar * +exim_rsa_verify_init(blob * pubkey_der, ev_ctx * verify_ctx) { - if( !ctx->N.p || !ctx->E.p ) - return( POLARSSL_ERR_RSA_KEY_CHECK_FAILED ); - - if( ( ctx->N.p[0] & 1 ) == 0 || - ( ctx->E.p[0] & 1 ) == 0 ) - return( POLARSSL_ERR_RSA_KEY_CHECK_FAILED ); +gnutls_datum_t k; +int rc; +const uschar * ret = NULL; - if( mpi_msb( &ctx->N ) < 128 || - mpi_msb( &ctx->N ) > 4096 ) - return( POLARSSL_ERR_RSA_KEY_CHECK_FAILED ); +gnutls_pubkey_init(&verify_ctx->rsa); - if( mpi_msb( &ctx->E ) < 2 || - mpi_msb( &ctx->E ) > 64 ) - return( POLARSSL_ERR_RSA_KEY_CHECK_FAILED ); +k.data = pubkey_der->data; +k.size = pubkey_der->len; - return( 0 ); +if ((rc = gnutls_pubkey_import(verify_ctx->rsa, &k, GNUTLS_X509_FMT_DER)) + != GNUTLS_E_SUCCESS) + ret = gnutls_strerror(rc); +return ret; } -/* - * Check a private RSA key - */ -int rsa_check_privkey( const rsa_context *ctx ) -{ - int ret; - mpi PQ, DE, P1, Q1, H, I, G, G2, L1, L2; - if( ( ret = rsa_check_pubkey( ctx ) ) != 0 ) - return( ret ); +/* verify signature (of hash) (given pubkey & alleged sig) +Return: NULL for success, or an error string */ - if( !ctx->P.p || !ctx->Q.p || !ctx->D.p ) - return( POLARSSL_ERR_RSA_KEY_CHECK_FAILED ); +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; +} - mpi_init( &PQ, &DE, &P1, &Q1, &H, &I, &G, &G2, &L1, &L2, NULL ); - MPI_CHK( mpi_mul_mpi( &PQ, &ctx->P, &ctx->Q ) ); - MPI_CHK( mpi_mul_mpi( &DE, &ctx->D, &ctx->E ) ); - MPI_CHK( mpi_sub_int( &P1, &ctx->P, 1 ) ); - MPI_CHK( mpi_sub_int( &Q1, &ctx->Q, 1 ) ); - MPI_CHK( mpi_mul_mpi( &H, &P1, &Q1 ) ); - MPI_CHK( mpi_gcd( &G, &ctx->E, &H ) ); - MPI_CHK( mpi_gcd( &G2, &P1, &Q1 ) ); - MPI_CHK( mpi_div_mpi( &L1, &L2, &H, &G2 ) ); - MPI_CHK( mpi_mod_mpi( &I, &DE, &L1 ) ); - /* - * Check for a valid PKCS1v2 private key - */ - if( mpi_cmp_mpi( &PQ, &ctx->N ) == 0 && - mpi_cmp_int( &L2, 0 ) == 0 && - mpi_cmp_int( &I, 1 ) == 0 && - mpi_cmp_int( &G, 1 ) == 0 ) - { - mpi_free( &G, &I, &H, &Q1, &P1, &DE, &PQ, &G2, &L1, &L2, NULL ); - return( 0 ); - } +#elif defined(RSA_GCRYPT) +/******************************************************************************/ -cleanup: +/* Internal service routine: +Read and move past an asn.1 header, checking class & tag, +optionally returning the data-length */ - mpi_free( &G, &I, &H, &Q1, &P1, &DE, &PQ, &G2, &L1, &L2, NULL ); - return( POLARSSL_ERR_RSA_KEY_CHECK_FAILED | ret ); -} - -/* - * Do an RSA public key operation - */ -int rsa_public( rsa_context *ctx, - const unsigned char *input, - unsigned char *output ) +static int +as_tag(blob * der, uschar req_cls, long req_tag, long * alen) { - int ret, olen; - mpi T; - - mpi_init( &T, NULL ); - - MPI_CHK( mpi_read_binary( &T, input, ctx->len ) ); +int rc; +uschar tag_class; +int taglen; +long tag, len; - if( mpi_cmp_mpi( &T, &ctx->N ) >= 0 ) - { - mpi_free( &T, NULL ); - return( POLARSSL_ERR_RSA_BAD_INPUT_DATA ); - } +/* debug_printf_indent("as_tag: %02x %02x %02x %02x\n", + der->data[0], der->data[1], der->data[2], der->data[3]); */ - olen = ctx->len; - MPI_CHK( mpi_exp_mod( &T, &T, &ctx->E, &ctx->N, &ctx->RN ) ); - MPI_CHK( mpi_write_binary( &T, output, olen ) ); +if ((rc = asn1_get_tag_der(der->data++, der->len--, &tag_class, &taglen, &tag)) + != ASN1_SUCCESS) + return rc; -cleanup: +if (tag_class != req_cls || tag != req_tag) return ASN1_ELEMENT_NOT_FOUND; - mpi_free( &T, NULL ); +if ((len = asn1_get_length_der(der->data, der->len, &taglen)) < 0) + return ASN1_DER_ERROR; +if (alen) *alen = len; - if( ret != 0 ) - return( POLARSSL_ERR_RSA_PUBLIC_FAILED | ret ); +/* debug_printf_indent("as_tag: tlen %d dlen %d\n", taglen, (int)len); */ - return( 0 ); +der->data += taglen; +der->len -= taglen; +return rc; } -/* - * Do an RSA private key operation - */ -int rsa_private( rsa_context *ctx, - const unsigned char *input, - unsigned char *output ) +/* 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) { - int ret, olen; - mpi T, T1, T2; - - mpi_init( &T, &T1, &T2, NULL ); - - MPI_CHK( mpi_read_binary( &T, input, ctx->len ) ); - - if( mpi_cmp_mpi( &T, &ctx->N ) >= 0 ) - { - mpi_free( &T, NULL ); - return( POLARSSL_ERR_RSA_BAD_INPUT_DATA ); - } - -#if 0 - MPI_CHK( mpi_exp_mod( &T, &T, &ctx->D, &ctx->N, &ctx->RN ) ); -#else - /* - * faster decryption using the CRT - * - * T1 = input ^ dP mod P - * T2 = input ^ dQ mod Q - */ - MPI_CHK( mpi_exp_mod( &T1, &T, &ctx->DP, &ctx->P, &ctx->RP ) ); - MPI_CHK( mpi_exp_mod( &T2, &T, &ctx->DQ, &ctx->Q, &ctx->RQ ) ); - - /* - * T = (T1 - T2) * (Q^-1 mod P) mod P - */ - MPI_CHK( mpi_sub_mpi( &T, &T1, &T2 ) ); - MPI_CHK( mpi_mul_mpi( &T1, &T, &ctx->QP ) ); - MPI_CHK( mpi_mod_mpi( &T, &T1, &ctx->P ) ); - - /* - * output = T2 + T * Q - */ - MPI_CHK( mpi_mul_mpi( &T1, &T, &ctx->Q ) ); - MPI_CHK( mpi_add_mpi( &T, &T2, &T1 ) ); -#endif +long alen; +int rc; +gcry_error_t gerr; - olen = ctx->len; - MPI_CHK( mpi_write_binary( &T, output, olen ) ); +/* integer; move past the header */ +if ((rc = as_tag(der, 0, ASN1_TAG_INTEGER, &alen)) != ASN1_SUCCESS) + return US asn1_strerror(rc); -cleanup: +/* read to an MPI */ +if ((gerr = gcry_mpi_scan(mpi, GCRYMPI_FMT_STD, der->data, alen, NULL))) + return US gcry_strerror(gerr); - mpi_free( &T, &T1, &T2, NULL ); +/* move over the data */ +der->data += alen; der->len -= alen; +return NULL; +} - if( ret != 0 ) - return( POLARSSL_ERR_RSA_PRIVATE_FAILED | ret ); - return( 0 ); -} -/* - * Add the message padding, then do an RSA operation - */ -int rsa_pkcs1_encrypt( rsa_context *ctx, - int (*f_rng)(void *), - void *p_rng, - int mode, int ilen, - const unsigned char *input, - unsigned char *output ) +void +exim_rsa_init(void) { - int nb_pad, olen; - unsigned char *p = output; +/* 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); + } - olen = ctx->len; +/* 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); - switch( ctx->padding ) - { - case RSA_PKCS_V15: +/* ... 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. */ - if( ilen < 0 || olen < ilen + 11 || f_rng == NULL ) - return( POLARSSL_ERR_RSA_BAD_INPUT_DATA ); +/* 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); - nb_pad = olen - 3 - ilen; +/* It is now okay to let Libgcrypt complain when there was/is +a problem with the secure memory. */ +gcry_control (GCRYCTL_RESUME_SECMEM_WARN); - *p++ = 0; - *p++ = RSA_CRYPT; +/* ... If required, other initialization goes here. */ - while( nb_pad-- > 0 ) - { - int rng_dl = 100; +/* Tell Libgcrypt that initialization has completed. */ +gcry_control (GCRYCTL_INITIALIZATION_FINISHED, 0); - do { - *p = (unsigned char) f_rng( p_rng ); - } while( *p == 0 && --rng_dl ); - - // Check if RNG failed to generate data - // - if( rng_dl == 0 ) - return POLARSSL_ERR_RSA_RNG_FAILED; +return; +} - p++; - } - *p++ = 0; - memcpy( p, input, ilen ); - break; - default: - return( POLARSSL_ERR_RSA_INVALID_PADDING ); - } - return( ( mode == RSA_PUBLIC ) - ? rsa_public( ctx, output, output ) - : rsa_private( ctx, output, output ) ); -} +/* Accumulate data (gnutls-only). +String to be appended must be nul-terminated. */ -/* - * Do an RSA operation, then remove the message padding - */ -int rsa_pkcs1_decrypt( rsa_context *ctx, - int mode, int *olen, - const unsigned char *input, - unsigned char *output, - int output_max_len) +blob * +exim_rsa_data_append(blob * b, int * alloc, uschar * s) { - int ret, ilen; - unsigned char *p; - unsigned char buf[1024]; - - ilen = ctx->len; +return b; /*dummy*/ +} - if( ilen < 16 || ilen > (int) sizeof( buf ) ) - return( POLARSSL_ERR_RSA_BAD_INPUT_DATA ); - ret = ( mode == RSA_PUBLIC ) - ? rsa_public( ctx, input, buf ) - : rsa_private( ctx, input, buf ); - if( ret != 0 ) - return( ret ); +/* import private key from PEM string in memory. +Return: NULL for success, or an error string */ - p = buf; +const uschar * +exim_rsa_signing_init(uschar * privkey_pem, es_ctx * sign_ctx) +{ +uschar * s1, * s2; +blob der; +long alen; +int rc; - switch( ctx->padding ) - { - case RSA_PKCS_V15: +/* + * 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); +} - if( *p++ != 0 || *p++ != RSA_CRYPT ) - return( POLARSSL_ERR_RSA_INVALID_PADDING ); - while( *p != 0 ) - { - if( p >= buf + ilen - 1 ) - return( POLARSSL_ERR_RSA_INVALID_PADDING ); - p++; - } - p++; - break; - default: +/* allocate mem for signature (when signing) */ +/* sign data (gnutls_only) +OR +sign hash. - return( POLARSSL_ERR_RSA_INVALID_PADDING ); - } +Return: NULL for success, or an error string */ - if (ilen - (int)(p - buf) > output_max_len) - return( POLARSSL_ERR_RSA_OUTPUT_TOO_LARGE ); +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; +} - *olen = ilen - (int)(p - buf); - memcpy( output, p, *olen ); - return( 0 ); -} +/* import public key (from DER in memory) +Return: NULL for success, or an error string */ -/* - * Do an RSA operation to sign the message digest - */ -int rsa_pkcs1_sign( rsa_context *ctx, - int mode, - int hash_id, - int hashlen, - const unsigned char *hash, - unsigned char *sig ) +const uschar * +exim_rsa_verify_init(blob * pubkey_der, ev_ctx * verify_ctx) { - int nb_pad, olen; - unsigned char *p = sig; - - olen = ctx->len; - - switch( ctx->padding ) - { - case RSA_PKCS_V15: - - switch( hash_id ) - { - case SIG_RSA_RAW: - nb_pad = olen - 3 - hashlen; - break; - - case SIG_RSA_MD2: - case SIG_RSA_MD4: - case SIG_RSA_MD5: - nb_pad = olen - 3 - 34; - break; - - case SIG_RSA_SHA1: - nb_pad = olen - 3 - 35; - break; - - case SIG_RSA_SHA224: - nb_pad = olen - 3 - 47; - break; - - case SIG_RSA_SHA256: - nb_pad = olen - 3 - 51; - break; - - case SIG_RSA_SHA384: - nb_pad = olen - 3 - 67; - break; - - case SIG_RSA_SHA512: - nb_pad = olen - 3 - 83; - break; - - - default: - return( POLARSSL_ERR_RSA_BAD_INPUT_DATA ); - } - - if( nb_pad < 8 ) - return( POLARSSL_ERR_RSA_BAD_INPUT_DATA ); - - *p++ = 0; - *p++ = RSA_SIGN; - memset( p, 0xFF, nb_pad ); - p += nb_pad; - *p++ = 0; - break; - - default: - - return( POLARSSL_ERR_RSA_INVALID_PADDING ); - } - - switch( hash_id ) - { - case SIG_RSA_RAW: - memcpy( p, hash, hashlen ); - break; - - case SIG_RSA_MD2: - memcpy( p, ASN1_HASH_MDX, 18 ); - memcpy( p + 18, hash, 16 ); - p[13] = 2; break; - - case SIG_RSA_MD4: - memcpy( p, ASN1_HASH_MDX, 18 ); - memcpy( p + 18, hash, 16 ); - p[13] = 4; break; - - case SIG_RSA_MD5: - memcpy( p, ASN1_HASH_MDX, 18 ); - memcpy( p + 18, hash, 16 ); - p[13] = 5; break; - - case SIG_RSA_SHA1: - memcpy( p, ASN1_HASH_SHA1, 15 ); - memcpy( p + 15, hash, 20 ); - break; - - case SIG_RSA_SHA224: - memcpy( p, ASN1_HASH_SHA2X, 19 ); - memcpy( p + 19, hash, 28 ); - p[1] += 28; p[14] = 4; p[18] += 28; break; - - case SIG_RSA_SHA256: - memcpy( p, ASN1_HASH_SHA2X, 19 ); - memcpy( p + 19, hash, 32 ); - p[1] += 32; p[14] = 1; p[18] += 32; break; - - case SIG_RSA_SHA384: - memcpy( p, ASN1_HASH_SHA2X, 19 ); - memcpy( p + 19, hash, 48 ); - p[1] += 48; p[14] = 2; p[18] += 48; break; - - case SIG_RSA_SHA512: - memcpy( p, ASN1_HASH_SHA2X, 19 ); - memcpy( p + 19, hash, 64 ); - p[1] += 64; p[14] = 3; p[18] += 64; break; - - default: - return( POLARSSL_ERR_RSA_BAD_INPUT_DATA ); - } - - return( ( mode == RSA_PUBLIC ) - ? rsa_public( ctx, sig, sig ) - : rsa_private( ctx, sig, sig ) ); -} - /* - * Do an RSA operation and check the message digest - */ -int rsa_pkcs1_verify( rsa_context *ctx, - int mode, - int hash_id, - int hashlen, - const unsigned char *hash, - unsigned char *sig ) -{ - int ret, len, siglen; - unsigned char *p, c; - unsigned char buf[1024]; - - siglen = ctx->len; - - if( siglen < 16 || siglen > (int) sizeof( buf ) ) - return( POLARSSL_ERR_RSA_BAD_INPUT_DATA ); - - ret = ( mode == RSA_PUBLIC ) - ? rsa_public( ctx, sig, buf ) - : rsa_private( ctx, sig, buf ); - - if( ret != 0 ) - return( ret ); - - p = buf; - - switch( ctx->padding ) - { - case RSA_PKCS_V15: - - if( *p++ != 0 || *p++ != RSA_SIGN ) - return( POLARSSL_ERR_RSA_INVALID_PADDING ); - - while( *p != 0 ) - { - if( p >= buf + siglen - 1 || *p != 0xFF ) - return( POLARSSL_ERR_RSA_INVALID_PADDING ); - p++; - } - p++; - break; - - default: - - return( POLARSSL_ERR_RSA_INVALID_PADDING ); - } - - len = siglen - (int)( p - buf ); - - if( len == 34 ) - { - c = p[13]; - p[13] = 0; - - if( memcmp( p, ASN1_HASH_MDX, 18 ) != 0 ) - return( POLARSSL_ERR_RSA_VERIFY_FAILED ); - - if( ( c == 2 && hash_id == SIG_RSA_MD2 ) || - ( c == 4 && hash_id == SIG_RSA_MD4 ) || - ( c == 5 && hash_id == SIG_RSA_MD5 ) ) - { - if( memcmp( p + 18, hash, 16 ) == 0 ) - return( 0 ); - else - return( POLARSSL_ERR_RSA_VERIFY_FAILED ); - } - } - - if( len == 35 && hash_id == SIG_RSA_SHA1 ) - { - if( memcmp( p, ASN1_HASH_SHA1, 15 ) == 0 && - memcmp( p + 15, hash, 20 ) == 0 ) - return( 0 ); - else - return( POLARSSL_ERR_RSA_VERIFY_FAILED ); - } - if( ( len == 19 + 28 && p[14] == 4 && hash_id == SIG_RSA_SHA224 ) || - ( len == 19 + 32 && p[14] == 1 && hash_id == SIG_RSA_SHA256 ) || - ( len == 19 + 48 && p[14] == 2 && hash_id == SIG_RSA_SHA384 ) || - ( len == 19 + 64 && p[14] == 3 && hash_id == SIG_RSA_SHA512 ) ) - { - c = p[1] - 17; - p[1] = 17; - p[14] = 0; - - if( p[18] == c && - memcmp( p, ASN1_HASH_SHA2X, 18 ) == 0 && - memcmp( p + 19, hash, c ) == 0 ) - return( 0 ); - else - return( POLARSSL_ERR_RSA_VERIFY_FAILED ); - } - - if( len == hashlen && hash_id == SIG_RSA_RAW ) - { - if( memcmp( p, hash, hashlen ) == 0 ) - return( 0 ); - else - return( POLARSSL_ERR_RSA_VERIFY_FAILED ); - } - - return( POLARSSL_ERR_RSA_INVALID_PADDING ); -} +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"; /* - * Free the components of an RSA key - */ -void rsa_free( rsa_context *ctx ) -{ - mpi_free( &ctx->RQ, &ctx->RP, &ctx->RN, - &ctx->QP, &ctx->DQ, &ctx->DP, - &ctx->Q, &ctx->P, &ctx->D, - &ctx->E, &ctx->N, NULL ); +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); } -#if defined(POLARSSL_SELF_TEST) -#include "polarssl/sha1.h" +/* verify signature (of hash) (given pubkey & alleged sig) +Return: NULL for success, or an error string */ -/* - * Example RSA-1024 keypair, for test purposes - */ -#define KEY_LEN 128 - -#define RSA_N "9292758453063D803DD603D5E777D788" \ - "8ED1D5BF35786190FA2F23EBC0848AEA" \ - "DDA92CA6C3D80B32C4D109BE0F36D6AE" \ - "7130B9CED7ACDF54CFC7555AC14EEBAB" \ - "93A89813FBF3C4F8066D2D800F7C38A8" \ - "1AE31942917403FF4946B0A83D3D3E05" \ - "EE57C6F5F5606FB5D4BC6CD34EE0801A" \ - "5E94BB77B07507233A0BC7BAC8F90F79" - -#define RSA_E "10001" - -#define RSA_D "24BF6185468786FDD303083D25E64EFC" \ - "66CA472BC44D253102F8B4A9D3BFA750" \ - "91386C0077937FE33FA3252D28855837" \ - "AE1B484A8A9A45F7EE8C0C634F99E8CD" \ - "DF79C5CE07EE72C7F123142198164234" \ - "CABB724CF78B8173B9F880FC86322407" \ - "AF1FEDFDDE2BEB674CA15F3E81A1521E" \ - "071513A1E85B5DFA031F21ECAE91A34D" - -#define RSA_P "C36D0EB7FCD285223CFB5AABA5BDA3D8" \ - "2C01CAD19EA484A87EA4377637E75500" \ - "FCB2005C5C7DD6EC4AC023CDA285D796" \ - "C3D9E75E1EFC42488BB4F1D13AC30A57" - -#define RSA_Q "C000DF51A7C77AE8D7C7370C1FF55B69" \ - "E211C2B9E5DB1ED0BF61D0D9899620F4" \ - "910E4168387E3C30AA1E00C339A79508" \ - "8452DD96A9A5EA5D9DCA68DA636032AF" - -#define RSA_DP "C1ACF567564274FB07A0BBAD5D26E298" \ - "3C94D22288ACD763FD8E5600ED4A702D" \ - "F84198A5F06C2E72236AE490C93F07F8" \ - "3CC559CD27BC2D1CA488811730BB5725" - -#define RSA_DQ "4959CBF6F8FEF750AEE6977C155579C7" \ - "D8AAEA56749EA28623272E4F7D0592AF" \ - "7C1F1313CAC9471B5C523BFE592F517B" \ - "407A1BD76C164B93DA2D32A383E58357" - -#define RSA_QP "9AE7FBC99546432DF71896FC239EADAE" \ - "F38D18D2B2F0E2DD275AA977E2BF4411" \ - "F5A3B2A5D33605AEBBCCBA7FEB9F2D2F" \ - "A74206CEC169D74BF5A8C50D6F48EA08" - -#define PT_LEN 24 -#define RSA_PT "\xAA\xBB\xCC\x03\x02\x01\x00\xFF\xFF\xFF\xFF\xFF" \ - "\x11\x22\x33\x0A\x0B\x0C\xCC\xDD\xDD\xDD\xDD\xDD" - -static int myrand( void *rng_state ) +const uschar * +exim_rsa_verify(ev_ctx * verify_ctx, BOOL is_sha1, blob * data_hash, blob * sig) { - if( rng_state != NULL ) - rng_state = NULL; - - return( rand() ); -} - /* - * Checkup routine - */ -int rsa_self_test( int verbose ) -{ - int len; - rsa_context rsa; - unsigned char sha1sum[20]; - unsigned char rsa_plaintext[PT_LEN]; - unsigned char rsa_decrypted[PT_LEN]; - unsigned char rsa_ciphertext[KEY_LEN]; +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; +} - rsa_init( &rsa, RSA_PKCS_V15, 0 ); - rsa.len = KEY_LEN; - mpi_read_string( &rsa.N , 16, RSA_N ); - mpi_read_string( &rsa.E , 16, RSA_E ); - mpi_read_string( &rsa.D , 16, RSA_D ); - mpi_read_string( &rsa.P , 16, RSA_P ); - mpi_read_string( &rsa.Q , 16, RSA_Q ); - mpi_read_string( &rsa.DP, 16, RSA_DP ); - mpi_read_string( &rsa.DQ, 16, RSA_DQ ); - mpi_read_string( &rsa.QP, 16, RSA_QP ); - if( verbose != 0 ) - printf( " RSA key validation: " ); - if( rsa_check_pubkey( &rsa ) != 0 || - rsa_check_privkey( &rsa ) != 0 ) - { - if( verbose != 0 ) - printf( "failed\n" ); +#elif defined(RSA_OPENSSL) +/******************************************************************************/ - return( 1 ); - } +void +exim_rsa_init(void) +{ +} - if( verbose != 0 ) - printf( "passed\n PKCS#1 encryption : " ); - memcpy( rsa_plaintext, RSA_PT, PT_LEN ); +/* accumulate data (gnutls-only) */ +blob * +exim_rsa_data_append(blob * b, int * alloc, uschar * s) +{ +return b; /*dummy*/ +} - if( rsa_pkcs1_encrypt( &rsa, &myrand, NULL, RSA_PUBLIC, PT_LEN, - rsa_plaintext, rsa_ciphertext ) != 0 ) - { - if( verbose != 0 ) - printf( "failed\n" ); - return( 1 ); - } +/* import private key from PEM string in memory. +Return: NULL for success, or an error string */ - if( verbose != 0 ) - printf( "passed\n PKCS#1 decryption : " ); +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; +} - if( rsa_pkcs1_decrypt( &rsa, RSA_PRIVATE, &len, - rsa_ciphertext, rsa_decrypted, - sizeof(rsa_decrypted) ) != 0 ) - { - if( verbose != 0 ) - printf( "failed\n" ); - return( 1 ); - } - if( memcmp( rsa_decrypted, rsa_plaintext, len ) != 0 ) - { - if( verbose != 0 ) - printf( "failed\n" ); +/* allocate mem for signature (when signing) */ +/* sign data (gnutls_only) +OR +sign hash. - return( 1 ); - } +Return: NULL for success, or an error string */ - if( verbose != 0 ) - printf( "passed\n PKCS#1 data sign : " ); +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;; +} - sha1( rsa_plaintext, PT_LEN, sha1sum ); - if( rsa_pkcs1_sign( &rsa, RSA_PRIVATE, SIG_RSA_SHA1, 20, - sha1sum, rsa_ciphertext ) != 0 ) - { - if( verbose != 0 ) - printf( "failed\n" ); - return( 1 ); - } +/* import public key (from DER in memory) +Return: nULL for success, or an error string */ - if( verbose != 0 ) - printf( "passed\n PKCS#1 sig. verify: " ); +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; +} - if( rsa_pkcs1_verify( &rsa, RSA_PUBLIC, SIG_RSA_SHA1, 20, - sha1sum, rsa_ciphertext ) != 0 ) - { - if( verbose != 0 ) - printf( "failed\n" ); - return( 1 ); - } - if( verbose != 0 ) - printf( "passed\n\n" ); - rsa_free( &rsa ); +/* verify signature (of hash) (given pubkey & alleged sig) +Return: NULL for success, or an error string */ - return( 0 ); +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 +/******************************************************************************/ + +#endif /*DISABLE_DKIM*/ +/* End of File */