Message ID | 1519534935-16053-1-git-send-email-selva.nair@gmail.com |
---|---|
State | Accepted |
Headers | show |
Series | None | expand |
Hi, On 25-02-18 06:02, selva.nair@gmail.com wrote: > From: Selva Nair <selva.nair@gmail.com> > > Requires openssl 1.1.0 or higher > > Signed-off-by: Selva Nair <selva.nair@gmail.com> > --- > v3 changes: > - check return value of ECDSA_SIG_set0 > - ensure buffer size needed by i2d_ECDSA_SIG does not exceed the expected > capacity of the sig buffer > - Fix a typo and add contextual info to a debug message > - Remove an superflous cast leftover from an older version > v4 changes: > - Add ECDSA_SIG_free() cleanup calls missed in v3 (2 places). > > src/openvpn/cryptoapi.c | 210 +++++++++++++++++++++++++++++++++++++++++++++++- > 1 file changed, 209 insertions(+), 1 deletion(-) > > diff --git a/src/openvpn/cryptoapi.c b/src/openvpn/cryptoapi.c > index 1097286..7e211f0 100644 > --- a/src/openvpn/cryptoapi.c > +++ b/src/openvpn/cryptoapi.c > @@ -1,5 +1,6 @@ > /* > * Copyright (c) 2004 Peter 'Luna' Runestig <peter@runestig.com> > + * Copyright (c) 2018 Selva Nair <selva.nair@gmail.com> > * All rights reserved. > * > * Redistribution and use in source and binary forms, with or without modifi- > @@ -101,6 +102,9 @@ static ERR_STRING_DATA CRYPTOAPI_str_functs[] = { > { 0, NULL } > }; > > +/* index for storing external data in EC_KEY: < 0 means uninitialized */ > +static int ec_data_idx = -1; > + > typedef struct _CAPI_DATA { > const CERT_CONTEXT *cert_context; > HCRYPTPROV_OR_NCRYPT_KEY_HANDLE crypt_prov; > @@ -394,6 +398,201 @@ finish(RSA *rsa) > return 1; > } > > +#if (OPENSSL_VERSION_NUMBER >= 0x10100000L) && !defined(OPENSSL_NO_EC) > + > +static EC_KEY_METHOD *ec_method = NULL; > + > +/** EC_KEY_METHOD callback: called when the key is freed */ > +static void > +ec_finish(EC_KEY *ec) > +{ > + EC_KEY_METHOD_free(ec_method); > + ec_method = NULL; > + CAPI_DATA *cd = EC_KEY_get_ex_data(ec, ec_data_idx); > + CAPI_DATA_free(cd); > + EC_KEY_set_ex_data(ec, ec_data_idx, NULL); > +} > + > +/** EC_KEY_METHOD callback sign_setup(): we do nothing here */ > +static int > +ecdsa_sign_setup(EC_KEY *eckey, BN_CTX *ctx_in, BIGNUM **kinvp, BIGNUM **rp) > +{ > + return 1; > +} > + > +/** > + * Helper to convert ECDSA signature returned by NCryptSignHash > + * to an ECDSA_SIG structure. > + * On entry 'buf[]' of length len contains r and s concatenated. > + * Returns a newly allocated ECDSA_SIG or NULL (on error). > + */ > +static ECDSA_SIG * > +ecdsa_bin2sig(unsigned char *buf, int len) > +{ > + ECDSA_SIG *ecsig = NULL; > + DWORD rlen = len/2; > + BIGNUM *r = BN_bin2bn(buf, rlen, NULL); > + BIGNUM *s = BN_bin2bn(buf+rlen, rlen, NULL); > + if (!r || !s) > + { > + goto err; > + } > + ecsig = ECDSA_SIG_new(); /* in openssl 1.1 this does not allocate r, s */ > + if (!ecsig) > + { > + goto err; > + } > + if (!ECDSA_SIG_set0(ecsig, r, s)) /* ecsig takes ownership of r and s */ > + { > + ECDSA_SIG_free(ecsig); > + goto err; > + } > + return ecsig; > +err: > + BN_free(r); /* it is ok to free NULL BN */ > + BN_free(s); > + return NULL; > +} > + > +/** EC_KEY_METHOD callback sign_sig(): sign and return an ECDSA_SIG pointer. */ > +static ECDSA_SIG * > +ecdsa_sign_sig(const unsigned char *dgst, int dgstlen, > + const BIGNUM *in_kinv, const BIGNUM *in_r, EC_KEY *ec) > +{ > + ECDSA_SIG *ecsig = NULL; > + CAPI_DATA *cd = (CAPI_DATA *)EC_KEY_get_ex_data(ec, ec_data_idx); > + > + ASSERT(cd->key_spec == CERT_NCRYPT_KEY_SPEC); > + > + NCRYPT_KEY_HANDLE hkey = cd->crypt_prov; > + BYTE buf[512]; /* large enough buffer for signature to avoid malloc */ > + DWORD len = _countof(buf); > + > + msg(D_LOW, "Cryptoapi: signing hash using EC key: data size = %d", dgstlen); > + > + DWORD status = NCryptSignHash(hkey, NULL, (BYTE *)dgst, dgstlen, (BYTE *)buf, len, &len, 0); > + if (status != ERROR_SUCCESS) > + { > + SetLastError(status); > + CRYPTOAPIerr(CRYPTOAPI_F_NCRYPT_SIGN_HASH); > + } > + else > + { > + /* NCryptSignHash returns r, s concatenated in buf[] */ > + ecsig = ecdsa_bin2sig(buf, len); > + } > + return ecsig; > +} > + > +/** EC_KEY_METHOD callback sign(): sign and return a DER encoded signature */ > +static int > +ecdsa_sign(int type, const unsigned char *dgst, int dgstlen, unsigned char *sig, > + unsigned int *siglen, const BIGNUM *kinv, const BIGNUM *r, EC_KEY *ec) > +{ > + ECDSA_SIG *s; > + > + *siglen = 0; > + s = ecdsa_sign_sig(dgst, dgstlen, NULL, NULL, ec); > + if (s == NULL) > + { > + return 0; > + } > + > + /* convert internal signature structure 's' to DER encoded byte array in sig */ > + int len = i2d_ECDSA_SIG(s, NULL); > + if (len > ECDSA_size(ec)) > + { > + ECDSA_SIG_free(s); > + msg(M_NONFATAL,"Error: DER encoded ECDSA signature is too long (%d bytes)", len); > + return 0; > + } > + *siglen = i2d_ECDSA_SIG(s, &sig); > + ECDSA_SIG_free(s); > + > + return 1; > +} > + > +static int > +ssl_ctx_set_eckey(SSL_CTX *ssl_ctx, CAPI_DATA *cd, EVP_PKEY *pkey) > +{ > + EC_KEY *ec = NULL; > + EVP_PKEY *privkey = NULL; > + > + if (cd->key_spec != CERT_NCRYPT_KEY_SPEC) > + { > + msg(M_NONFATAL, "ERROR: cryptoapicert with only legacy private key handle available." > + " EC certificate not supported."); > + goto err; > + } > + /* create a method struct with default callbacks filled in */ > + ec_method = EC_KEY_METHOD_new(EC_KEY_OpenSSL()); > + if (!ec_method) > + { > + goto err; > + } > + > + /* We only need to set finish among init methods, and sign methods */ > + EC_KEY_METHOD_set_init(ec_method, NULL, ec_finish, NULL, NULL, NULL, NULL); > + EC_KEY_METHOD_set_sign(ec_method, ecdsa_sign, ecdsa_sign_setup, ecdsa_sign_sig); > + > + ec = EC_KEY_dup(EVP_PKEY_get0_EC_KEY(pkey)); > + if (!ec) > + { > + goto err; > + } > + if (!EC_KEY_set_method(ec, ec_method)) > + { > + goto err; > + } > + > + /* get an index to store cd as external data */ > + if (ec_data_idx < 0) > + { > + ec_data_idx = EC_KEY_get_ex_new_index(0, "cryptapicert ec key", NULL, NULL, NULL); > + if (ec_data_idx < 0) > + { > + goto err; > + } > + } > + EC_KEY_set_ex_data(ec, ec_data_idx, cd); > + > + /* cd assigned to ec as ex_data, increase its refcount */ > + cd->ref_count++; > + > + privkey = EVP_PKEY_new(); > + if (!EVP_PKEY_assign_EC_KEY(privkey, ec)) > + { > + EC_KEY_free(ec); > + goto err; > + } > + /* from here on ec will get freed with privkey */ > + > + if (!SSL_CTX_use_PrivateKey(ssl_ctx, privkey)) > + { > + goto err; > + } > + EVP_PKEY_free(privkey); /* this will dn_ref or free ec as well */ > + return 1; > + > +err: > + if (privkey) > + { > + EVP_PKEY_free(privkey); > + } > + else if (ec) > + { > + EC_KEY_free(ec); > + } > + if (ec_method) /* do always set ec_method = NULL after freeing it */ > + { > + EC_KEY_METHOD_free(ec_method); > + ec_method = NULL; > + } > + return 0; > +} > + > +#endif /* OPENSSL_VERSION_NUMBER >= 1.1.0 */ > + > static const CERT_CONTEXT * > find_certificate_in_store(const char *cert_prop, HCERTSTORE cert_store) > { > @@ -642,9 +841,18 @@ SSL_CTX_use_CryptoAPI_certificate(SSL_CTX *ssl_ctx, const char *cert_prop) > goto err; > } > } > +#if (OPENSSL_VERSION_NUMBER >= 0x10100000L) && !defined(OPENSSL_NO_EC) > + else if (EVP_PKEY_id(pkey) == EVP_PKEY_EC) > + { > + if (!ssl_ctx_set_eckey(ssl_ctx, cd, pkey)) > + { > + goto err; > + } > + } > +#endif /* OPENSSL_VERSION_NUMBER >= 1.1.0 */ > else > { > - msg(M_WARN, "cryptoapicert requires an RSA certificate"); > + msg(M_WARN, "WARNING: cryptoapicert: certificate type not supported"); > goto err; > } > CAPI_DATA_free(cd); /* this will do a ref_count-- */ > Thanks, changes wrt v2 look good, so: Acked-by: Steffan Karger <steffan@karger.me> -Steffan ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot
Compile-tested on OpenBSD 6.0 (no EC/LibreSSL hickup, good :-) ) and mingw / ubuntu 16.04. All well. Your patch has been applied to the master branch. (Is there a strong case for including it in 2.4?) commit a6f38bafbbbd291d57ecb3610c2844e7f7e01412 Author: Selva Nair Date: Sun Feb 25 00:02:15 2018 -0500 Support EC certificates with cryptoapicert Signed-off-by: Selva Nair <selva.nair@gmail.com> Acked-by: Steffan Karger <steffan.karger@fox-it.com> Message-Id: <1519534935-16053-1-git-send-email-selva.nair@gmail.com> URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg16553.html Signed-off-by: Gert Doering <gert@greenie.muc.de> -- kind regards, Gert Doering ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot
diff --git a/src/openvpn/cryptoapi.c b/src/openvpn/cryptoapi.c index 1097286..7e211f0 100644 --- a/src/openvpn/cryptoapi.c +++ b/src/openvpn/cryptoapi.c @@ -1,5 +1,6 @@ /* * Copyright (c) 2004 Peter 'Luna' Runestig <peter@runestig.com> + * Copyright (c) 2018 Selva Nair <selva.nair@gmail.com> * All rights reserved. * * Redistribution and use in source and binary forms, with or without modifi- @@ -101,6 +102,9 @@ static ERR_STRING_DATA CRYPTOAPI_str_functs[] = { { 0, NULL } }; +/* index for storing external data in EC_KEY: < 0 means uninitialized */ +static int ec_data_idx = -1; + typedef struct _CAPI_DATA { const CERT_CONTEXT *cert_context; HCRYPTPROV_OR_NCRYPT_KEY_HANDLE crypt_prov; @@ -394,6 +398,201 @@ finish(RSA *rsa) return 1; } +#if (OPENSSL_VERSION_NUMBER >= 0x10100000L) && !defined(OPENSSL_NO_EC) + +static EC_KEY_METHOD *ec_method = NULL; + +/** EC_KEY_METHOD callback: called when the key is freed */ +static void +ec_finish(EC_KEY *ec) +{ + EC_KEY_METHOD_free(ec_method); + ec_method = NULL; + CAPI_DATA *cd = EC_KEY_get_ex_data(ec, ec_data_idx); + CAPI_DATA_free(cd); + EC_KEY_set_ex_data(ec, ec_data_idx, NULL); +} + +/** EC_KEY_METHOD callback sign_setup(): we do nothing here */ +static int +ecdsa_sign_setup(EC_KEY *eckey, BN_CTX *ctx_in, BIGNUM **kinvp, BIGNUM **rp) +{ + return 1; +} + +/** + * Helper to convert ECDSA signature returned by NCryptSignHash + * to an ECDSA_SIG structure. + * On entry 'buf[]' of length len contains r and s concatenated. + * Returns a newly allocated ECDSA_SIG or NULL (on error). + */ +static ECDSA_SIG * +ecdsa_bin2sig(unsigned char *buf, int len) +{ + ECDSA_SIG *ecsig = NULL; + DWORD rlen = len/2; + BIGNUM *r = BN_bin2bn(buf, rlen, NULL); + BIGNUM *s = BN_bin2bn(buf+rlen, rlen, NULL); + if (!r || !s) + { + goto err; + } + ecsig = ECDSA_SIG_new(); /* in openssl 1.1 this does not allocate r, s */ + if (!ecsig) + { + goto err; + } + if (!ECDSA_SIG_set0(ecsig, r, s)) /* ecsig takes ownership of r and s */ + { + ECDSA_SIG_free(ecsig); + goto err; + } + return ecsig; +err: + BN_free(r); /* it is ok to free NULL BN */ + BN_free(s); + return NULL; +} + +/** EC_KEY_METHOD callback sign_sig(): sign and return an ECDSA_SIG pointer. */ +static ECDSA_SIG * +ecdsa_sign_sig(const unsigned char *dgst, int dgstlen, + const BIGNUM *in_kinv, const BIGNUM *in_r, EC_KEY *ec) +{ + ECDSA_SIG *ecsig = NULL; + CAPI_DATA *cd = (CAPI_DATA *)EC_KEY_get_ex_data(ec, ec_data_idx); + + ASSERT(cd->key_spec == CERT_NCRYPT_KEY_SPEC); + + NCRYPT_KEY_HANDLE hkey = cd->crypt_prov; + BYTE buf[512]; /* large enough buffer for signature to avoid malloc */ + DWORD len = _countof(buf); + + msg(D_LOW, "Cryptoapi: signing hash using EC key: data size = %d", dgstlen); + + DWORD status = NCryptSignHash(hkey, NULL, (BYTE *)dgst, dgstlen, (BYTE *)buf, len, &len, 0); + if (status != ERROR_SUCCESS) + { + SetLastError(status); + CRYPTOAPIerr(CRYPTOAPI_F_NCRYPT_SIGN_HASH); + } + else + { + /* NCryptSignHash returns r, s concatenated in buf[] */ + ecsig = ecdsa_bin2sig(buf, len); + } + return ecsig; +} + +/** EC_KEY_METHOD callback sign(): sign and return a DER encoded signature */ +static int +ecdsa_sign(int type, const unsigned char *dgst, int dgstlen, unsigned char *sig, + unsigned int *siglen, const BIGNUM *kinv, const BIGNUM *r, EC_KEY *ec) +{ + ECDSA_SIG *s; + + *siglen = 0; + s = ecdsa_sign_sig(dgst, dgstlen, NULL, NULL, ec); + if (s == NULL) + { + return 0; + } + + /* convert internal signature structure 's' to DER encoded byte array in sig */ + int len = i2d_ECDSA_SIG(s, NULL); + if (len > ECDSA_size(ec)) + { + ECDSA_SIG_free(s); + msg(M_NONFATAL,"Error: DER encoded ECDSA signature is too long (%d bytes)", len); + return 0; + } + *siglen = i2d_ECDSA_SIG(s, &sig); + ECDSA_SIG_free(s); + + return 1; +} + +static int +ssl_ctx_set_eckey(SSL_CTX *ssl_ctx, CAPI_DATA *cd, EVP_PKEY *pkey) +{ + EC_KEY *ec = NULL; + EVP_PKEY *privkey = NULL; + + if (cd->key_spec != CERT_NCRYPT_KEY_SPEC) + { + msg(M_NONFATAL, "ERROR: cryptoapicert with only legacy private key handle available." + " EC certificate not supported."); + goto err; + } + /* create a method struct with default callbacks filled in */ + ec_method = EC_KEY_METHOD_new(EC_KEY_OpenSSL()); + if (!ec_method) + { + goto err; + } + + /* We only need to set finish among init methods, and sign methods */ + EC_KEY_METHOD_set_init(ec_method, NULL, ec_finish, NULL, NULL, NULL, NULL); + EC_KEY_METHOD_set_sign(ec_method, ecdsa_sign, ecdsa_sign_setup, ecdsa_sign_sig); + + ec = EC_KEY_dup(EVP_PKEY_get0_EC_KEY(pkey)); + if (!ec) + { + goto err; + } + if (!EC_KEY_set_method(ec, ec_method)) + { + goto err; + } + + /* get an index to store cd as external data */ + if (ec_data_idx < 0) + { + ec_data_idx = EC_KEY_get_ex_new_index(0, "cryptapicert ec key", NULL, NULL, NULL); + if (ec_data_idx < 0) + { + goto err; + } + } + EC_KEY_set_ex_data(ec, ec_data_idx, cd); + + /* cd assigned to ec as ex_data, increase its refcount */ + cd->ref_count++; + + privkey = EVP_PKEY_new(); + if (!EVP_PKEY_assign_EC_KEY(privkey, ec)) + { + EC_KEY_free(ec); + goto err; + } + /* from here on ec will get freed with privkey */ + + if (!SSL_CTX_use_PrivateKey(ssl_ctx, privkey)) + { + goto err; + } + EVP_PKEY_free(privkey); /* this will dn_ref or free ec as well */ + return 1; + +err: + if (privkey) + { + EVP_PKEY_free(privkey); + } + else if (ec) + { + EC_KEY_free(ec); + } + if (ec_method) /* do always set ec_method = NULL after freeing it */ + { + EC_KEY_METHOD_free(ec_method); + ec_method = NULL; + } + return 0; +} + +#endif /* OPENSSL_VERSION_NUMBER >= 1.1.0 */ + static const CERT_CONTEXT * find_certificate_in_store(const char *cert_prop, HCERTSTORE cert_store) { @@ -642,9 +841,18 @@ SSL_CTX_use_CryptoAPI_certificate(SSL_CTX *ssl_ctx, const char *cert_prop) goto err; } } +#if (OPENSSL_VERSION_NUMBER >= 0x10100000L) && !defined(OPENSSL_NO_EC) + else if (EVP_PKEY_id(pkey) == EVP_PKEY_EC) + { + if (!ssl_ctx_set_eckey(ssl_ctx, cd, pkey)) + { + goto err; + } + } +#endif /* OPENSSL_VERSION_NUMBER >= 1.1.0 */ else { - msg(M_WARN, "cryptoapicert requires an RSA certificate"); + msg(M_WARN, "WARNING: cryptoapicert: certificate type not supported"); goto err; } CAPI_DATA_free(cd); /* this will do a ref_count-- */