X-Git-Url: https://git.exim.org/exim.git/blobdiff_plain/80a47a2c9633437d4ceebd214cd44abfbd4f4543..e1d04f48a45c9f8e8ff75610003048f8ead73219:/src/src/pdkim/rsa.c diff --git a/src/src/pdkim/rsa.c b/src/src/pdkim/rsa.c index 992a396aa..548bae6be 100644 --- a/src/src/pdkim/rsa.c +++ b/src/src/pdkim/rsa.c @@ -1,822 +1,679 @@ /* - * The RSA public-key cryptosystem + * PDKIM - a RFC4871 (DKIM) implementation * - * Based on XySSL: Copyright (C) 2006-2008 Christophe Devine + * Copyright (C) 2016 Exim maintainers * - * Copyright (C) 2009 Paul Bakker - * - * 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 */ -/* $Cambridge: exim/src/src/pdkim/rsa.c,v 1.2 2009/06/10 07:34:05 tom Exp $ */ +#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" -#include "base64.h" -#include -#include -#include +/******************************************************************************/ +#ifdef RSA_GNUTLS -/* - * ASN.1 DER decoding routines - */ -static int asn1_get_len( unsigned char **p, - unsigned char *end, - int *len ) +void +exim_rsa_init(void) { - if( ( end - *p ) < 1 ) - return( POLARSSL_ERR_ASN1_OUT_OF_DATA ); - - if( ( **p & 0x80 ) == 0 ) - *len = *(*p)++; - else - { - switch( **p & 0x7F ) - { - case 1: - if( ( end - *p ) < 2 ) - return( POLARSSL_ERR_ASN1_OUT_OF_DATA ); - - *len = (*p)[1]; - (*p) += 2; - break; - - case 2: - if( ( end - *p ) < 3 ) - return( POLARSSL_ERR_ASN1_OUT_OF_DATA ); - - *len = ( (*p)[1] << 8 ) | (*p)[2]; - (*p) += 3; - break; - - default: - return( POLARSSL_ERR_ASN1_INVALID_LENGTH ); - break; - } - } - - if( *len > (int) ( end - *p ) ) - return( POLARSSL_ERR_ASN1_OUT_OF_DATA ); - - return( 0 ); } -static int asn1_get_tag( unsigned char **p, - unsigned char *end, - int *len, int tag ) + +/* accumulate data (gnutls-only). String to be appended must be nul-terminated. */ +blob * +exim_rsa_data_append(blob * b, int * alloc, uschar * s) { - if( ( end - *p ) < 1 ) - return( POLARSSL_ERR_ASN1_OUT_OF_DATA ); +int len = b->len; +b->data = string_append(b->data, alloc, &len, 1, s); +b->len = len; +return b; +} - if( **p != tag ) - return( POLARSSL_ERR_ASN1_UNEXPECTED_TAG ); - (*p)++; - return( asn1_get_len( p, end, len ) ); -} +/* import private key from PEM string in memory. +Return: NULL for success, or an error string */ -static int asn1_get_int( unsigned char **p, - unsigned char *end, - int *val ) +const uschar * +exim_rsa_signing_init(uschar * privkey_pem, es_ctx * sign_ctx) { - int ret, len; - - if( ( ret = asn1_get_tag( p, end, &len, ASN1_INTEGER ) ) != 0 ) - return( ret ); +gnutls_datum_t k; +int rc; - if( len > (int) sizeof( int ) || ( **p & 0x80 ) != 0 ) - return( POLARSSL_ERR_ASN1_INVALID_LENGTH ); +k.data = privkey_pem; +k.size = strlen(privkey_pem); - *val = 0; +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); - while( len-- > 0 ) - { - *val = ( *val << 8 ) | **p; - (*p)++; - } +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( 0 ); +return NULL; } -static int asn1_get_mpi( unsigned char **p, - unsigned char *end, - mpi *X ) -{ - int ret, len; - if( ( ret = asn1_get_tag( p, end, &len, ASN1_INTEGER ) ) != 0 ) - return( ret ); - ret = mpi_read_binary( X, *p, len ); +/* allocate mem for signature (when signing) */ +/* sign data (gnutls_only) +OR +sign hash. - *p += len; +Return: NULL for success, or an error string */ - return( ret ); +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; } -/* - * Initialize an RSA context - */ -void rsa_init( rsa_context *ctx, - int padding, - int hash_id, - int (*f_rng)(void *), - void *p_rng ) + +/* 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) { - memset( ctx, 0, sizeof( rsa_context ) ); +gnutls_datum_t k; +int rc; +const uschar * ret = NULL; + +gnutls_pubkey_init(&verify_ctx->rsa); - ctx->padding = padding; - ctx->hash_id = hash_id; +k.data = pubkey_der->data; +k.size = pubkey_der->len; - ctx->f_rng = f_rng; - ctx->p_rng = p_rng; +if ((rc = gnutls_pubkey_import(verify_ctx->rsa, &k, GNUTLS_X509_FMT_DER)) + != GNUTLS_E_SUCCESS) + ret = gnutls_strerror(rc); +return ret; } -/* - * Check a public RSA key - */ -int rsa_check_pubkey( rsa_context *ctx ) +/* 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) { - if( ( ctx->N.p[0] & 1 ) == 0 || - ( ctx->E.p[0] & 1 ) == 0 ) - return( POLARSSL_ERR_RSA_KEY_CHECK_FAILED ); +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; +} - if( mpi_msb( &ctx->N ) < 128 || - mpi_msb( &ctx->N ) > 4096 ) - return( POLARSSL_ERR_RSA_KEY_CHECK_FAILED ); - if( mpi_msb( &ctx->E ) < 2 || - mpi_msb( &ctx->E ) > 64 ) - return( POLARSSL_ERR_RSA_KEY_CHECK_FAILED ); - return( 0 ); -} -/* - * Check a private RSA key - */ -int rsa_check_privkey( rsa_context *ctx ) -{ - int ret; - mpi PQ, DE, P1, Q1, H, I, G; - - if( ( ret = rsa_check_pubkey( ctx ) ) != 0 ) - return( ret ); - - mpi_init( &PQ, &DE, &P1, &Q1, &H, &I, &G, 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_mod_mpi( &I, &DE, &H ) ); - MPI_CHK( mpi_gcd( &G, &ctx->E, &H ) ); - - if( mpi_cmp_mpi( &PQ, &ctx->N ) == 0 && - mpi_cmp_int( &I, 1 ) == 0 && - mpi_cmp_int( &G, 1 ) == 0 ) - { - mpi_free( &G, &I, &H, &Q1, &P1, &DE, &PQ, NULL ); - return( 0 ); - } - -cleanup: - - mpi_free( &G, &I, &H, &Q1, &P1, &DE, &PQ, NULL ); - return( POLARSSL_ERR_RSA_KEY_CHECK_FAILED | ret ); -} +#elif defined(RSA_GCRYPT) +/******************************************************************************/ -/* - * Do an RSA public key operation - */ -int rsa_public( rsa_context *ctx, - unsigned char *input, - unsigned char *output ) -{ - int ret, olen; - mpi T; - mpi_init( &T, NULL ); +/* Internal service routine: +Read and move past an asn.1 header, checking class & tag, +optionally returning the data-length */ - MPI_CHK( mpi_read_binary( &T, input, ctx->len ) ); +static int +as_tag(blob * der, uschar req_cls, long req_tag, long * alen) +{ +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 ); - } +/* acl_debug_printf("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 ); +/* acl_debug_printf("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, - 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 mode, int ilen, - 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); + } + +/* 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. */ - olen = ctx->len; +/* 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); - switch( ctx->padding ) - { - case RSA_PKCS_V15: +/* 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( ilen < 0 || olen < ilen + 11 ) - return( POLARSSL_ERR_RSA_BAD_INPUT_DATA ); +/* ... If required, other initialization goes here. */ - nb_pad = olen - 3 - ilen; +/* Tell Libgcrypt that initialization has completed. */ +gcry_control (GCRYCTL_INITIALIZATION_FINISHED, 0); + +return; +} - *p++ = 0; - *p++ = RSA_CRYPT; - while( nb_pad-- > 0 ) - { - do { - *p = (unsigned char) rand(); - } while( *p == 0 ); - p++; - } - *p++ = 0; - memcpy( p, input, ilen ); - break; - default: - return( POLARSSL_ERR_RSA_INVALID_PADDING ); - } +/* Accumulate data (gnutls-only). +String to be appended must be nul-terminated. */ - return( ( mode == RSA_PUBLIC ) - ? rsa_public( ctx, output, output ) - : rsa_private( ctx, output, output ) ); +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; + /* - * Do an RSA operation, then remove the message padding + * 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 */ -int rsa_pkcs1_decrypt( rsa_context *ctx, - int mode, int *olen, - unsigned char *input, - unsigned char *output, - int output_max_len) + +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) acl_debug_printf("rsa_signing_init:\n"); + { + uschar * s; + gcry_mpi_aprint (GCRYMPI_FMT_HEX, &s, NULL, sign_ctx->n); + acl_debug_printf(" N : %s\n", s); + gcry_mpi_aprint (GCRYMPI_FMT_HEX, &s, NULL, sign_ctx->e); + acl_debug_printf(" E : %s\n", s); + gcry_mpi_aprint (GCRYMPI_FMT_HEX, &s, NULL, sign_ctx->d); + acl_debug_printf(" D : %s\n", s); + gcry_mpi_aprint (GCRYMPI_FMT_HEX, &s, NULL, sign_ctx->p); + acl_debug_printf(" P : %s\n", s); + gcry_mpi_aprint (GCRYMPI_FMT_HEX, &s, NULL, sign_ctx->q); + acl_debug_printf(" Q : %s\n", s); + gcry_mpi_aprint (GCRYMPI_FMT_HEX, &s, NULL, sign_ctx->dp); + acl_debug_printf(" DP: %s\n", s); + gcry_mpi_aprint (GCRYMPI_FMT_HEX, &s, NULL, sign_ctx->dq); + acl_debug_printf(" DQ: %s\n", s); + gcry_mpi_aprint (GCRYMPI_FMT_HEX, &s, NULL, sign_ctx->qp); + acl_debug_printf(" 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) { - int ret, ilen; - unsigned char *p; - unsigned char buf[512]; +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); + acl_debug_printf(" SG: %s\n", s); + } + +gerr = gcry_mpi_print(GCRYMPI_FMT_USG, sig->data, SIGSPACE, &sig->len, m_sig); +if (gerr) + { + acl_debug_printf("signature conversion from MPI to buffer failed\n"); + return US gcry_strerror(gerr); + } +#undef SIGSPACE + +return NULL; +} - ilen = ctx->len; - if( ilen < 16 || ilen > (int) sizeof( buf ) ) - return( POLARSSL_ERR_RSA_BAD_INPUT_DATA ); +/* import public key (from DER in memory) +Return: NULL for success, or an error string */ - ret = ( mode == RSA_PUBLIC ) - ? rsa_public( ctx, input, buf ) - : rsa_private( ctx, input, buf ); +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"; - if( ret != 0 ) - return( ret ); +/* +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; +*/ - p = buf; +/* 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) acl_debug_printf("rsa_verify_init:\n"); + { + uschar * s; + gcry_mpi_aprint (GCRYMPI_FMT_HEX, &s, NULL, verify_ctx->n); + acl_debug_printf(" N : %s\n", s); + gcry_mpi_aprint (GCRYMPI_FMT_HEX, &s, NULL, verify_ctx->e); + acl_debug_printf(" 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); +} - switch( ctx->padding ) - { - case RSA_PKCS_V15: - if( *p++ != 0 || *p++ != RSA_CRYPT ) - return( POLARSSL_ERR_RSA_INVALID_PADDING ); +/* verify signature (of hash) (given pubkey & alleged sig) +Return: NULL for success, or an error string */ - while( *p != 0 ) - { - if( p >= buf + ilen - 1 ) - return( POLARSSL_ERR_RSA_INVALID_PADDING ); - p++; - } - p++; - break; +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) acl_debug_printf("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; +} - default: - return( POLARSSL_ERR_RSA_INVALID_PADDING ); - } - if (ilen - (int)(p - buf) > output_max_len) - return( POLARSSL_ERR_RSA_OUTPUT_TO_LARGE ); - *olen = ilen - (int)(p - buf); - memcpy( output, p, *olen ); +#elif defined(RSA_OPENSSL) +/******************************************************************************/ - return( 0 ); +void +exim_rsa_init(void) +{ } -/* - * Do an RSA operation to sign the message digest - */ -int rsa_pkcs1_sign( rsa_context *ctx, - int mode, - int hash_id, - int hashlen, - unsigned char *hash, - unsigned char *sig ) + +/* accumulate data (gnutls-only) */ +blob * +exim_rsa_data_append(blob * b, int * alloc, uschar * s) { - int nb_pad, olen; - unsigned char *p = sig; - - olen = ctx->len; - - switch( ctx->padding ) - { - case RSA_PKCS_V15: - - switch( hash_id ) - { - case RSA_RAW: - nb_pad = olen - 3 - hashlen; - break; - - case RSA_MD2: - case RSA_MD4: - case RSA_MD5: - nb_pad = olen - 3 - 16 - 18; - break; - - case RSA_SHA1: - nb_pad = olen - 3 - 20 - 15; - break; - - case RSA_SHA256: - nb_pad = olen - 3 - 32 - 19; - 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 RSA_RAW: - memcpy( p, hash, hashlen ); - break; - - case RSA_MD2: - memcpy( p, ASN1_HASH_MDX, 18 ); - memcpy( p + 18, hash, 16 ); - p[13] = 2; break; - - case RSA_MD4: - memcpy( p, ASN1_HASH_MDX, 18 ); - memcpy( p + 18, hash, 16 ); - p[13] = 4; break; - - case RSA_MD5: - memcpy( p, ASN1_HASH_MDX, 18 ); - memcpy( p + 18, hash, 16 ); - p[13] = 5; break; - - case RSA_SHA1: - memcpy( p, ASN1_HASH_SHA1, 15 ); - memcpy( p + 15, hash, 20 ); - break; - - case RSA_SHA256: - memcpy( p, ASN1_HASH_SHA256, 19 ); - memcpy( p + 19, hash, 32 ); - break; - - default: - return( POLARSSL_ERR_RSA_BAD_INPUT_DATA ); - } - - return( ( mode == RSA_PUBLIC ) - ? rsa_public( ctx, sig, sig ) - : rsa_private( ctx, sig, sig ) ); +return b; /*dummy*/ } -/* - * Do an RSA operation and check the message digest - */ -int rsa_pkcs1_verify( rsa_context *ctx, - int mode, - int hash_id, - int hashlen, - unsigned char *hash, - unsigned char *sig ) + +/* 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) { - int ret, len, siglen; - unsigned char *p, c; - unsigned char buf[512]; - - 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 == RSA_MD2 ) || - ( c == 4 && hash_id == RSA_MD4 ) || - ( c == 5 && hash_id == RSA_MD5 ) ) - { - if( memcmp( p + 18, hash, 16 ) == 0 ) - return( 0 ); - else - return( POLARSSL_ERR_RSA_VERIFY_FAILED ); - } - } - - if( len == 35 && hash_id == 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 == 51 && hash_id == RSA_SHA256 ) - { - if( memcmp( p, ASN1_HASH_SHA256, 19 ) == 0 && - memcmp( p + 19, hash, 32 ) == 0 ) - return( 0 ); - else - return( POLARSSL_ERR_RSA_VERIFY_FAILED ); - } - - if( len == hashlen && hash_id == RSA_RAW ) - { - if( memcmp( p, hash, hashlen ) == 0 ) - return( 0 ); - else - return( POLARSSL_ERR_RSA_VERIFY_FAILED ); - } - - return( POLARSSL_ERR_RSA_INVALID_PADDING ); +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; } -/* - * Free the components of an RSA key - */ -void rsa_free( rsa_context *ctx ) + + +/* 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) { - 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 ); +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;; } -/* - * Parse a public RSA key - -OpenSSL RSA public key ASN1 container - 0:d=0 hl=3 l= 159 cons: SEQUENCE - 3:d=1 hl=2 l= 13 cons: SEQUENCE - 5:d=2 hl=2 l= 9 prim: OBJECT:rsaEncryption - 16:d=2 hl=2 l= 0 prim: NULL - 18:d=1 hl=3 l= 141 prim: BIT STRING:RSAPublicKey (below) - -RSAPublicKey ASN1 container - 0:d=0 hl=3 l= 137 cons: SEQUENCE - 3:d=1 hl=3 l= 129 prim: INTEGER:Public modulus -135:d=1 hl=2 l= 3 prim: INTEGER:Public exponent -*/ -int rsa_parse_public_key( rsa_context *rsa, unsigned char *buf, int buflen ) +/* 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) { - unsigned char *p, *end; - int ret, len; - - p = buf; - end = buf+buflen; - - if( ( ret = asn1_get_tag( &p, end, &len, - ASN1_CONSTRUCTED | ASN1_SEQUENCE ) ) != 0 ) { - return( POLARSSL_ERR_X509_KEY_INVALID_FORMAT | ret ); - } - - if( ( ret = asn1_get_tag( &p, end, &len, - ASN1_CONSTRUCTED | ASN1_SEQUENCE ) ) == 0 ) { - /* Skip over embedded rsaEncryption Object */ - p+=len; - - /* The RSAPublicKey ASN1 container is wrapped in a BIT STRING */ - if( ( ret = asn1_get_tag( &p, end, &len, - ASN1_BIT_STRING ) ) != 0 ) { - return( POLARSSL_ERR_X509_KEY_INVALID_FORMAT | ret ); - } - - /* Limit range to that BIT STRING */ - end = p + len; - p++; - - if( ( ret = asn1_get_tag( &p, end, &len, - ASN1_CONSTRUCTED | ASN1_SEQUENCE ) ) != 0 ) { - return( POLARSSL_ERR_X509_KEY_INVALID_FORMAT | ret ); - } - } - - if ( ( ( ret = asn1_get_mpi( &p, end, &(rsa->N) ) ) == 0 ) && - ( ( ret = asn1_get_mpi( &p, end, &(rsa->E) ) ) == 0 ) ) { - rsa->len = mpi_size( &rsa->N ); - return 0; - } - - return( POLARSSL_ERR_X509_KEY_INVALID_FORMAT | ret ); +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; } -/* - * Parse a private RSA key - */ -int rsa_parse_key( rsa_context *rsa, unsigned char *buf, int buflen, - unsigned char *pwd, int pwdlen ) + + + +/* 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) { - int ret, len, enc; - unsigned char *s1, *s2; - unsigned char *p, *end; - - s1 = (unsigned char *) strstr( (char *) buf, - "-----BEGIN RSA PRIVATE KEY-----" ); - - if( s1 != NULL ) - { - s2 = (unsigned char *) strstr( (char *) buf, - "-----END RSA PRIVATE KEY-----" ); - - if( s2 == NULL || s2 <= s1 ) - return( POLARSSL_ERR_X509_KEY_INVALID_PEM ); - - s1 += 31; - if( *s1 == '\r' ) s1++; - if( *s1 == '\n' ) s1++; - else return( POLARSSL_ERR_X509_KEY_INVALID_PEM ); - - enc = 0; - - if( memcmp( s1, "Proc-Type: 4,ENCRYPTED", 22 ) == 0 ) - { - return( POLARSSL_ERR_X509_FEATURE_UNAVAILABLE ); - } - - len = 0; - ret = base64_decode( NULL, &len, s1, s2 - s1 ); - - if( ret == POLARSSL_ERR_BASE64_INVALID_CHARACTER ) - return( ret | POLARSSL_ERR_X509_KEY_INVALID_PEM ); - - if( ( buf = (unsigned char *) malloc( len ) ) == NULL ) - return( 1 ); - - if( ( ret = base64_decode( buf, &len, s1, s2 - s1 ) ) != 0 ) - { - free( buf ); - return( ret | POLARSSL_ERR_X509_KEY_INVALID_PEM ); - } - - buflen = len; - - if( enc != 0 ) - { - return( POLARSSL_ERR_X509_FEATURE_UNAVAILABLE ); - } - } - - memset( rsa, 0, sizeof( rsa_context ) ); - - p = buf; - end = buf + buflen; - - /* - * 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( ( ret = asn1_get_tag( &p, end, &len, - ASN1_CONSTRUCTED | ASN1_SEQUENCE ) ) != 0 ) - { - if( s1 != NULL ) - free( buf ); - - rsa_free( rsa ); - return( POLARSSL_ERR_X509_KEY_INVALID_FORMAT | ret ); - } - - end = p + len; - - if( ( ret = asn1_get_int( &p, end, &rsa->ver ) ) != 0 ) - { - if( s1 != NULL ) - free( buf ); - - rsa_free( rsa ); - return( POLARSSL_ERR_X509_KEY_INVALID_FORMAT | ret ); - } - - if( rsa->ver != 0 ) - { - if( s1 != NULL ) - free( buf ); - - rsa_free( rsa ); - return( ret | POLARSSL_ERR_X509_KEY_INVALID_VERSION ); - } - - if( ( ret = asn1_get_mpi( &p, end, &rsa->N ) ) != 0 || - ( ret = asn1_get_mpi( &p, end, &rsa->E ) ) != 0 || - ( ret = asn1_get_mpi( &p, end, &rsa->D ) ) != 0 || - ( ret = asn1_get_mpi( &p, end, &rsa->P ) ) != 0 || - ( ret = asn1_get_mpi( &p, end, &rsa->Q ) ) != 0 || - ( ret = asn1_get_mpi( &p, end, &rsa->DP ) ) != 0 || - ( ret = asn1_get_mpi( &p, end, &rsa->DQ ) ) != 0 || - ( ret = asn1_get_mpi( &p, end, &rsa->QP ) ) != 0 ) - { - if( s1 != NULL ) - free( buf ); - - rsa_free( rsa ); - return( ret | POLARSSL_ERR_X509_KEY_INVALID_FORMAT ); - } - - rsa->len = mpi_size( &rsa->N ); - - if( p != end ) - { - if( s1 != NULL ) - free( buf ); - - rsa_free( rsa ); - return( POLARSSL_ERR_X509_KEY_INVALID_FORMAT | - POLARSSL_ERR_ASN1_LENGTH_MISMATCH ); - } - - if( ( ret = rsa_check_privkey( rsa ) ) != 0 ) - { - if( s1 != NULL ) - free( buf ); - - rsa_free( rsa ); - return( ret ); - } - - if( s1 != NULL ) - free( buf ); - - return( 0 ); +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 */