diff options
Diffstat (limited to 'src/libstrongswan/plugins/gmp/gmp_rsa_public_key.c')
| -rw-r--r-- | src/libstrongswan/plugins/gmp/gmp_rsa_public_key.c | 128 |
1 files changed, 125 insertions, 3 deletions
diff --git a/src/libstrongswan/plugins/gmp/gmp_rsa_public_key.c b/src/libstrongswan/plugins/gmp/gmp_rsa_public_key.c index 065c88903..52bc9fb38 100644 --- a/src/libstrongswan/plugins/gmp/gmp_rsa_public_key.c +++ b/src/libstrongswan/plugins/gmp/gmp_rsa_public_key.c @@ -1,7 +1,8 @@ /* + * Copyright (C) 2017 Tobias Brunner * Copyright (C) 2005-2009 Martin Willi * Copyright (C) 2005 Jan Hutter - * Hochschule fuer Technik Rapperswil + * HSR Hochschule fuer Technik Rapperswil * * 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 @@ -27,6 +28,7 @@ #include <asn1/asn1.h> #include <asn1/asn1_parser.h> #include <crypto/hashers/hasher.h> +#include <credentials/keys/signature_params.h> #ifdef HAVE_MPZ_POWM_SEC # undef mpz_powm @@ -126,7 +128,7 @@ static const asn1Object_t digestInfoObjects[] = { #define DIGEST_INFO_DIGEST 2 /** - * Verification of an EMPSA PKCS1 signature described in PKCS#1 + * Verification of an EMSA PKCS1 signature described in PKCS#1 */ static bool verify_emsa_pkcs1_signature(private_gmp_rsa_public_key_t *this, hash_algorithm_t algorithm, @@ -283,6 +285,124 @@ end: return success; } +/** + * Verification of an EMSA PSS signature described in PKCS#1 + */ +static bool verify_emsa_pss_signature(private_gmp_rsa_public_key_t *this, + rsa_pss_params_t *params, chunk_t data, + chunk_t signature) +{ + ext_out_function_t xof; + hasher_t *hasher = NULL; + xof_t *mgf = NULL; + chunk_t em, hash, salt, db, h, dbmask, m; + size_t embits, maskbits; + int i; + bool success = FALSE; + + if (!params) + { + return FALSE; + } + xof = xof_mgf1_from_hash_algorithm(params->mgf1_hash); + if (xof == XOF_UNDEFINED) + { + DBG1(DBG_LIB, "%N is not supported for MGF1", hash_algorithm_names, + params->mgf1_hash); + return FALSE; + } + chunk_skip_zero(signature); + if (signature.len == 0 || signature.len > this->k) + { + return FALSE; + } + /* EM = RSAVP1((n, e), S) */ + em = rsavp1(this, signature); + if (!em.len) + { + goto error; + } + /* emBits = modBits - 1 */ + embits = mpz_sizeinbase(this->n, 2) - 1; + /* mHash = Hash(M) */ + hasher = lib->crypto->create_hasher(lib->crypto, params->hash); + if (!hasher) + { + DBG1(DBG_LIB, "hash algorithm %N not supported", + hash_algorithm_names, params->hash); + goto error; + } + hash = chunk_alloca(hasher->get_hash_size(hasher)); + if (!hasher->get_hash(hasher, data, hash.ptr)) + { + goto error; + } + /* determine salt length */ + salt.len = hash.len; + if (params->salt_len > RSA_PSS_SALT_LEN_DEFAULT) + { + salt.len = params->salt_len; + } + /* verify general structure of EM */ + maskbits = (8 * em.len) - embits; + if (em.len < (hash.len + salt.len + 2) || em.ptr[em.len-1] != 0xbc || + (em.ptr[0] & (0xff << (8-maskbits)))) + { /* inconsistent */ + goto error; + } + /* split EM in maskedDB and H */ + db = chunk_create(em.ptr, em.len - hash.len - 1); + h = chunk_create(em.ptr + db.len, hash.len); + /* dbMask = MGF(H, emLen - hLen - 1) */ + mgf = lib->crypto->create_xof(lib->crypto, xof); + if (!mgf) + { + DBG1(DBG_LIB, "%N not supported", ext_out_function_names, xof); + goto error; + } + dbmask = chunk_alloca(db.len); + if (!mgf->set_seed(mgf, h) || + !mgf->get_bytes(mgf, dbmask.len, dbmask.ptr)) + { + DBG1(DBG_LIB, "%N not supported or failed", ext_out_function_names, xof); + goto error; + } + /* DB = maskedDB xor dbMask */ + memxor(db.ptr, dbmask.ptr, db.len); + if (maskbits) + { + db.ptr[0] &= (0xff >> maskbits); + } + /* check DB = PS | 0x01 | salt */ + for (i = 0; i < (db.len - salt.len - 1); i++) + { + if (db.ptr[i]) + { /* padding not 0 */ + goto error; + } + } + if (db.ptr[i++] != 0x01) + { /* 0x01 not found */ + goto error; + } + salt.ptr = &db.ptr[i]; + /* M' = 0x0000000000000000 | mHash | salt */ + m = chunk_cata("ccc", + chunk_from_chars(0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00), + hash, salt); + if (!hasher->get_hash(hasher, m, hash.ptr)) + { + goto error; + } + success = memeq_const(h.ptr, hash.ptr, hash.len); + +error: + DESTROY_IF(hasher); + DESTROY_IF(mgf); + free(em.ptr); + return success; +} + METHOD(public_key_t, get_type, key_type_t, private_gmp_rsa_public_key_t *this) { @@ -290,7 +410,7 @@ METHOD(public_key_t, get_type, key_type_t, } METHOD(public_key_t, verify, bool, - private_gmp_rsa_public_key_t *this, signature_scheme_t scheme, + private_gmp_rsa_public_key_t *this, signature_scheme_t scheme, void *params, chunk_t data, chunk_t signature) { switch (scheme) @@ -317,6 +437,8 @@ METHOD(public_key_t, verify, bool, return verify_emsa_pkcs1_signature(this, HASH_SHA1, data, signature); case SIGN_RSA_EMSA_PKCS1_MD5: return verify_emsa_pkcs1_signature(this, HASH_MD5, data, signature); + case SIGN_RSA_EMSA_PSS: + return verify_emsa_pss_signature(this, params, data, signature); default: DBG1(DBG_LIB, "signature scheme %N not supported in RSA", signature_scheme_names, scheme); |