/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com) * All rights reserved. * * This package is an SSL implementation written * by Eric Young (eay@cryptsoft.com). * The implementation was written so as to conform with Netscapes SSL. * * This library is free for commercial and non-commercial use as long as * the following conditions are aheared to. The following conditions * apply to all code found in this distribution, be it the RC4, RSA, * lhash, DES, etc., code; not just the SSL code. The SSL documentation * included with this distribution is covered by the same copyright terms * except that the holder is Tim Hudson (tjh@cryptsoft.com). * * Copyright remains Eric Young's, and as such any Copyright notices in * the code are not to be removed. * If this package is used in a product, Eric Young should be given attribution * as the author of the parts of the library used. * This can be in the form of a textual message at program startup or * in documentation (online or textual) provided with the package. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * "This product includes cryptographic software written by * Eric Young (eay@cryptsoft.com)" * The word 'cryptographic' can be left out if the rouines from the library * being used are not cryptographic related :-). * 4. If you include any Windows specific code (or a derivative thereof) from * the apps directory (application code) you must include an acknowledgement: * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)" * * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * The licence and distribution terms for any publically available version or * derivative of this code cannot be changed. i.e. this code cannot simply be * copied and put under another distribution licence * [including the GNU Public Licence.] */ #include #include #include #include #include #include #include #include #include "internal.h" #include "../crypto/internal.h" BSSL_NAMESPACE_BEGIN bool ssl_is_key_type_supported(int key_type) { return key_type == EVP_PKEY_RSA || key_type == EVP_PKEY_EC || key_type == EVP_PKEY_ED25519; } static bool ssl_set_pkey(CERT *cert, EVP_PKEY *pkey) { if (!ssl_is_key_type_supported(pkey->type)) { OPENSSL_PUT_ERROR(SSL, SSL_R_UNKNOWN_CERTIFICATE_TYPE); return false; } if (cert->chain != nullptr && sk_CRYPTO_BUFFER_value(cert->chain.get(), 0) != nullptr && // Sanity-check that the private key and the certificate match. !ssl_cert_check_private_key(cert, pkey)) { return false; } cert->privatekey = UpRef(pkey); return true; } typedef struct { uint16_t sigalg; int pkey_type; int curve; const EVP_MD *(*digest_func)(void); bool is_rsa_pss; } SSL_SIGNATURE_ALGORITHM; static const SSL_SIGNATURE_ALGORITHM kSignatureAlgorithms[] = { {SSL_SIGN_RSA_PKCS1_MD5_SHA1, EVP_PKEY_RSA, NID_undef, &EVP_md5_sha1, false}, {SSL_SIGN_RSA_PKCS1_SHA1, EVP_PKEY_RSA, NID_undef, &EVP_sha1, false}, {SSL_SIGN_RSA_PKCS1_SHA256, EVP_PKEY_RSA, NID_undef, &EVP_sha256, false}, {SSL_SIGN_RSA_PKCS1_SHA384, EVP_PKEY_RSA, NID_undef, &EVP_sha384, false}, {SSL_SIGN_RSA_PKCS1_SHA512, EVP_PKEY_RSA, NID_undef, &EVP_sha512, false}, {SSL_SIGN_RSA_PSS_RSAE_SHA256, EVP_PKEY_RSA, NID_undef, &EVP_sha256, true}, {SSL_SIGN_RSA_PSS_RSAE_SHA384, EVP_PKEY_RSA, NID_undef, &EVP_sha384, true}, {SSL_SIGN_RSA_PSS_RSAE_SHA512, EVP_PKEY_RSA, NID_undef, &EVP_sha512, true}, {SSL_SIGN_ECDSA_SHA1, EVP_PKEY_EC, NID_undef, &EVP_sha1, false}, {SSL_SIGN_ECDSA_SECP256R1_SHA256, EVP_PKEY_EC, NID_X9_62_prime256v1, &EVP_sha256, false}, {SSL_SIGN_ECDSA_SECP384R1_SHA384, EVP_PKEY_EC, NID_secp384r1, &EVP_sha384, false}, {SSL_SIGN_ECDSA_SECP521R1_SHA512, EVP_PKEY_EC, NID_secp521r1, &EVP_sha512, false}, {SSL_SIGN_ED25519, EVP_PKEY_ED25519, NID_undef, nullptr, false}, }; static const SSL_SIGNATURE_ALGORITHM *get_signature_algorithm(uint16_t sigalg) { for (size_t i = 0; i < OPENSSL_ARRAY_SIZE(kSignatureAlgorithms); i++) { if (kSignatureAlgorithms[i].sigalg == sigalg) { return &kSignatureAlgorithms[i]; } } return NULL; } bool ssl_has_private_key(const SSL_HANDSHAKE *hs) { if (hs->config->cert->privatekey != nullptr || hs->config->cert->key_method != nullptr || ssl_signing_with_dc(hs)) { return true; } return false; } static bool pkey_supports_algorithm(const SSL *ssl, EVP_PKEY *pkey, uint16_t sigalg) { const SSL_SIGNATURE_ALGORITHM *alg = get_signature_algorithm(sigalg); if (alg == NULL || EVP_PKEY_id(pkey) != alg->pkey_type) { return false; } if (ssl_protocol_version(ssl) >= TLS1_3_VERSION) { // RSA keys may only be used with RSA-PSS. if (alg->pkey_type == EVP_PKEY_RSA && !alg->is_rsa_pss) { return false; } // EC keys have a curve requirement. if (alg->pkey_type == EVP_PKEY_EC && (alg->curve == NID_undef || EC_GROUP_get_curve_name( EC_KEY_get0_group(EVP_PKEY_get0_EC_KEY(pkey))) != alg->curve)) { return false; } } return true; } static bool setup_ctx(SSL *ssl, EVP_MD_CTX *ctx, EVP_PKEY *pkey, uint16_t sigalg, bool is_verify) { if (!pkey_supports_algorithm(ssl, pkey, sigalg)) { OPENSSL_PUT_ERROR(SSL, SSL_R_WRONG_SIGNATURE_TYPE); return false; } const SSL_SIGNATURE_ALGORITHM *alg = get_signature_algorithm(sigalg); const EVP_MD *digest = alg->digest_func != NULL ? alg->digest_func() : NULL; EVP_PKEY_CTX *pctx; if (is_verify) { if (!EVP_DigestVerifyInit(ctx, &pctx, digest, NULL, pkey)) { return false; } } else if (!EVP_DigestSignInit(ctx, &pctx, digest, NULL, pkey)) { return false; } if (alg->is_rsa_pss) { if (!EVP_PKEY_CTX_set_rsa_padding(pctx, RSA_PKCS1_PSS_PADDING) || !EVP_PKEY_CTX_set_rsa_pss_saltlen(pctx, -1 /* salt len = hash len */)) { return false; } } return true; } enum ssl_private_key_result_t ssl_private_key_sign( SSL_HANDSHAKE *hs, uint8_t *out, size_t *out_len, size_t max_out, uint16_t sigalg, Span in) { SSL *const ssl = hs->ssl; const SSL_PRIVATE_KEY_METHOD *key_method = hs->config->cert->key_method; EVP_PKEY *privatekey = hs->config->cert->privatekey.get(); if (ssl_signing_with_dc(hs)) { key_method = hs->config->cert->dc_key_method; privatekey = hs->config->cert->dc_privatekey.get(); } if (key_method != NULL) { enum ssl_private_key_result_t ret; if (hs->pending_private_key_op) { ret = key_method->complete(ssl, out, out_len, max_out); } else { ret = key_method->sign(ssl, out, out_len, max_out, sigalg, in.data(), in.size()); } if (ret == ssl_private_key_failure) { OPENSSL_PUT_ERROR(SSL, SSL_R_PRIVATE_KEY_OPERATION_FAILED); } hs->pending_private_key_op = ret == ssl_private_key_retry; return ret; } *out_len = max_out; ScopedEVP_MD_CTX ctx; if (!setup_ctx(ssl, ctx.get(), privatekey, sigalg, false /* sign */) || !EVP_DigestSign(ctx.get(), out, out_len, in.data(), in.size())) { return ssl_private_key_failure; } return ssl_private_key_success; } bool ssl_public_key_verify(SSL *ssl, Span signature, uint16_t sigalg, EVP_PKEY *pkey, Span in) { ScopedEVP_MD_CTX ctx; return setup_ctx(ssl, ctx.get(), pkey, sigalg, true /* verify */) && EVP_DigestVerify(ctx.get(), signature.data(), signature.size(), in.data(), in.size()); } enum ssl_private_key_result_t ssl_private_key_decrypt(SSL_HANDSHAKE *hs, uint8_t *out, size_t *out_len, size_t max_out, Span in) { SSL *const ssl = hs->ssl; if (hs->config->cert->key_method != NULL) { enum ssl_private_key_result_t ret; if (hs->pending_private_key_op) { ret = hs->config->cert->key_method->complete(ssl, out, out_len, max_out); } else { ret = hs->config->cert->key_method->decrypt(ssl, out, out_len, max_out, in.data(), in.size()); } if (ret == ssl_private_key_failure) { OPENSSL_PUT_ERROR(SSL, SSL_R_PRIVATE_KEY_OPERATION_FAILED); } hs->pending_private_key_op = ret == ssl_private_key_retry; return ret; } RSA *rsa = EVP_PKEY_get0_RSA(hs->config->cert->privatekey.get()); if (rsa == NULL) { // Decrypt operations are only supported for RSA keys. OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR); return ssl_private_key_failure; } // Decrypt with no padding. PKCS#1 padding will be removed as part of the // timing-sensitive code by the caller. if (!RSA_decrypt(rsa, out_len, out, max_out, in.data(), in.size(), RSA_NO_PADDING)) { return ssl_private_key_failure; } return ssl_private_key_success; } bool ssl_private_key_supports_signature_algorithm(SSL_HANDSHAKE *hs, uint16_t sigalg) { SSL *const ssl = hs->ssl; if (!pkey_supports_algorithm(ssl, hs->local_pubkey.get(), sigalg)) { return false; } // Ensure the RSA key is large enough for the hash. RSASSA-PSS requires that // emLen be at least hLen + sLen + 2. Both hLen and sLen are the size of the // hash in TLS. Reasonable RSA key sizes are large enough for the largest // defined RSASSA-PSS algorithm, but 1024-bit RSA is slightly too small for // SHA-512. 1024-bit RSA is sometimes used for test credentials, so check the // size so that we can fall back to another algorithm in that case. const SSL_SIGNATURE_ALGORITHM *alg = get_signature_algorithm(sigalg); if (alg->is_rsa_pss && (size_t)EVP_PKEY_size(hs->local_pubkey.get()) < 2 * EVP_MD_size(alg->digest_func()) + 2) { return false; } return true; } BSSL_NAMESPACE_END using namespace bssl; int SSL_use_RSAPrivateKey(SSL *ssl, RSA *rsa) { if (rsa == NULL || ssl->config == NULL) { OPENSSL_PUT_ERROR(SSL, ERR_R_PASSED_NULL_PARAMETER); return 0; } UniquePtr pkey(EVP_PKEY_new()); if (!pkey || !EVP_PKEY_set1_RSA(pkey.get(), rsa)) { OPENSSL_PUT_ERROR(SSL, ERR_R_EVP_LIB); return 0; } return ssl_set_pkey(ssl->config->cert.get(), pkey.get()); } int SSL_use_RSAPrivateKey_ASN1(SSL *ssl, const uint8_t *der, size_t der_len) { UniquePtr rsa(RSA_private_key_from_bytes(der, der_len)); if (!rsa) { OPENSSL_PUT_ERROR(SSL, ERR_R_ASN1_LIB); return 0; } return SSL_use_RSAPrivateKey(ssl, rsa.get()); } int SSL_use_PrivateKey(SSL *ssl, EVP_PKEY *pkey) { if (pkey == NULL || ssl->config == NULL) { OPENSSL_PUT_ERROR(SSL, ERR_R_PASSED_NULL_PARAMETER); return 0; } return ssl_set_pkey(ssl->config->cert.get(), pkey); } int SSL_use_PrivateKey_ASN1(int type, SSL *ssl, const uint8_t *der, size_t der_len) { if (der_len > LONG_MAX) { OPENSSL_PUT_ERROR(SSL, ERR_R_OVERFLOW); return 0; } const uint8_t *p = der; UniquePtr pkey(d2i_PrivateKey(type, NULL, &p, (long)der_len)); if (!pkey || p != der + der_len) { OPENSSL_PUT_ERROR(SSL, ERR_R_ASN1_LIB); return 0; } return SSL_use_PrivateKey(ssl, pkey.get()); } int SSL_CTX_use_RSAPrivateKey(SSL_CTX *ctx, RSA *rsa) { if (rsa == NULL) { OPENSSL_PUT_ERROR(SSL, ERR_R_PASSED_NULL_PARAMETER); return 0; } UniquePtr pkey(EVP_PKEY_new()); if (!pkey || !EVP_PKEY_set1_RSA(pkey.get(), rsa)) { OPENSSL_PUT_ERROR(SSL, ERR_R_EVP_LIB); return 0; } return ssl_set_pkey(ctx->cert.get(), pkey.get()); } int SSL_CTX_use_RSAPrivateKey_ASN1(SSL_CTX *ctx, const uint8_t *der, size_t der_len) { UniquePtr rsa(RSA_private_key_from_bytes(der, der_len)); if (!rsa) { OPENSSL_PUT_ERROR(SSL, ERR_R_ASN1_LIB); return 0; } return SSL_CTX_use_RSAPrivateKey(ctx, rsa.get()); } int SSL_CTX_use_PrivateKey(SSL_CTX *ctx, EVP_PKEY *pkey) { if (pkey == NULL) { OPENSSL_PUT_ERROR(SSL, ERR_R_PASSED_NULL_PARAMETER); return 0; } return ssl_set_pkey(ctx->cert.get(), pkey); } int SSL_CTX_use_PrivateKey_ASN1(int type, SSL_CTX *ctx, const uint8_t *der, size_t der_len) { if (der_len > LONG_MAX) { OPENSSL_PUT_ERROR(SSL, ERR_R_OVERFLOW); return 0; } const uint8_t *p = der; UniquePtr pkey(d2i_PrivateKey(type, NULL, &p, (long)der_len)); if (!pkey || p != der + der_len) { OPENSSL_PUT_ERROR(SSL, ERR_R_ASN1_LIB); return 0; } return SSL_CTX_use_PrivateKey(ctx, pkey.get()); } void SSL_set_private_key_method(SSL *ssl, const SSL_PRIVATE_KEY_METHOD *key_method) { if (!ssl->config) { return; } ssl->config->cert->key_method = key_method; } void SSL_CTX_set_private_key_method(SSL_CTX *ctx, const SSL_PRIVATE_KEY_METHOD *key_method) { ctx->cert->key_method = key_method; } static constexpr size_t kMaxSignatureAlgorithmNameLen = 23; // This was "constexpr" rather than "const", but that triggered a bug in MSVC // where it didn't pad the strings to the correct length. static const struct { uint16_t signature_algorithm; const char name[kMaxSignatureAlgorithmNameLen]; } kSignatureAlgorithmNames[] = { {SSL_SIGN_RSA_PKCS1_MD5_SHA1, "rsa_pkcs1_md5_sha1"}, {SSL_SIGN_RSA_PKCS1_SHA1, "rsa_pkcs1_sha1"}, {SSL_SIGN_RSA_PKCS1_SHA256, "rsa_pkcs1_sha256"}, {SSL_SIGN_RSA_PKCS1_SHA384, "rsa_pkcs1_sha384"}, {SSL_SIGN_RSA_PKCS1_SHA512, "rsa_pkcs1_sha512"}, {SSL_SIGN_ECDSA_SHA1, "ecdsa_sha1"}, {SSL_SIGN_ECDSA_SECP256R1_SHA256, "ecdsa_secp256r1_sha256"}, {SSL_SIGN_ECDSA_SECP384R1_SHA384, "ecdsa_secp384r1_sha384"}, {SSL_SIGN_ECDSA_SECP521R1_SHA512, "ecdsa_secp521r1_sha512"}, {SSL_SIGN_RSA_PSS_RSAE_SHA256, "rsa_pss_rsae_sha256"}, {SSL_SIGN_RSA_PSS_RSAE_SHA384, "rsa_pss_rsae_sha384"}, {SSL_SIGN_RSA_PSS_RSAE_SHA512, "rsa_pss_rsae_sha512"}, {SSL_SIGN_ED25519, "ed25519"}, }; const char *SSL_get_signature_algorithm_name(uint16_t sigalg, int include_curve) { if (!include_curve) { switch (sigalg) { case SSL_SIGN_ECDSA_SECP256R1_SHA256: return "ecdsa_sha256"; case SSL_SIGN_ECDSA_SECP384R1_SHA384: return "ecdsa_sha384"; case SSL_SIGN_ECDSA_SECP521R1_SHA512: return "ecdsa_sha512"; } } for (const auto &candidate : kSignatureAlgorithmNames) { if (candidate.signature_algorithm == sigalg) { return candidate.name; } } return NULL; } int SSL_get_signature_algorithm_key_type(uint16_t sigalg) { const SSL_SIGNATURE_ALGORITHM *alg = get_signature_algorithm(sigalg); return alg != nullptr ? alg->pkey_type : EVP_PKEY_NONE; } const EVP_MD *SSL_get_signature_algorithm_digest(uint16_t sigalg) { const SSL_SIGNATURE_ALGORITHM *alg = get_signature_algorithm(sigalg); if (alg == nullptr || alg->digest_func == nullptr) { return nullptr; } return alg->digest_func(); } int SSL_is_signature_algorithm_rsa_pss(uint16_t sigalg) { const SSL_SIGNATURE_ALGORITHM *alg = get_signature_algorithm(sigalg); return alg != nullptr && alg->is_rsa_pss; } int SSL_CTX_set_signing_algorithm_prefs(SSL_CTX *ctx, const uint16_t *prefs, size_t num_prefs) { return ctx->cert->sigalgs.CopyFrom(MakeConstSpan(prefs, num_prefs)); } int SSL_set_signing_algorithm_prefs(SSL *ssl, const uint16_t *prefs, size_t num_prefs) { if (!ssl->config) { return 0; } return ssl->config->cert->sigalgs.CopyFrom(MakeConstSpan(prefs, num_prefs)); } static constexpr struct { int pkey_type; int hash_nid; uint16_t signature_algorithm; } kSignatureAlgorithmsMapping[] = { {EVP_PKEY_RSA, NID_sha1, SSL_SIGN_RSA_PKCS1_SHA1}, {EVP_PKEY_RSA, NID_sha256, SSL_SIGN_RSA_PKCS1_SHA256}, {EVP_PKEY_RSA, NID_sha384, SSL_SIGN_RSA_PKCS1_SHA384}, {EVP_PKEY_RSA, NID_sha512, SSL_SIGN_RSA_PKCS1_SHA512}, {EVP_PKEY_RSA_PSS, NID_sha256, SSL_SIGN_RSA_PSS_RSAE_SHA256}, {EVP_PKEY_RSA_PSS, NID_sha384, SSL_SIGN_RSA_PSS_RSAE_SHA384}, {EVP_PKEY_RSA_PSS, NID_sha512, SSL_SIGN_RSA_PSS_RSAE_SHA512}, {EVP_PKEY_EC, NID_sha1, SSL_SIGN_ECDSA_SHA1}, {EVP_PKEY_EC, NID_sha256, SSL_SIGN_ECDSA_SECP256R1_SHA256}, {EVP_PKEY_EC, NID_sha384, SSL_SIGN_ECDSA_SECP384R1_SHA384}, {EVP_PKEY_EC, NID_sha512, SSL_SIGN_ECDSA_SECP521R1_SHA512}, {EVP_PKEY_ED25519, NID_undef, SSL_SIGN_ED25519}, }; static bool parse_sigalg_pairs(Array *out, const int *values, size_t num_values) { if ((num_values & 1) == 1) { return false; } const size_t num_pairs = num_values / 2; if (!out->Init(num_pairs)) { return false; } for (size_t i = 0; i < num_values; i += 2) { const int hash_nid = values[i]; const int pkey_type = values[i+1]; bool found = false; for (const auto &candidate : kSignatureAlgorithmsMapping) { if (candidate.pkey_type == pkey_type && candidate.hash_nid == hash_nid) { (*out)[i / 2] = candidate.signature_algorithm; found = true; break; } } if (!found) { OPENSSL_PUT_ERROR(SSL, SSL_R_INVALID_SIGNATURE_ALGORITHM); ERR_add_error_dataf("unknown hash:%d pkey:%d", hash_nid, pkey_type); return false; } } return true; } static int compare_uint16_t(const void *p1, const void *p2) { uint16_t u1 = *((const uint16_t *)p1); uint16_t u2 = *((const uint16_t *)p2); if (u1 < u2) { return -1; } else if (u1 > u2) { return 1; } else { return 0; } } static bool sigalgs_unique(Span in_sigalgs) { if (in_sigalgs.size() < 2) { return true; } Array sigalgs; if (!sigalgs.CopyFrom(in_sigalgs)) { return false; } qsort(sigalgs.data(), sigalgs.size(), sizeof(uint16_t), compare_uint16_t); for (size_t i = 1; i < sigalgs.size(); i++) { if (sigalgs[i - 1] == sigalgs[i]) { OPENSSL_PUT_ERROR(SSL, SSL_R_DUPLICATE_SIGNATURE_ALGORITHM); return false; } } return true; } int SSL_CTX_set1_sigalgs(SSL_CTX *ctx, const int *values, size_t num_values) { Array sigalgs; if (!parse_sigalg_pairs(&sigalgs, values, num_values) || !sigalgs_unique(sigalgs)) { return 0; } if (!SSL_CTX_set_signing_algorithm_prefs(ctx, sigalgs.data(), sigalgs.size()) || !ctx->verify_sigalgs.CopyFrom(sigalgs)) { return 0; } return 1; } int SSL_set1_sigalgs(SSL *ssl, const int *values, size_t num_values) { if (!ssl->config) { OPENSSL_PUT_ERROR(SSL, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED); return 0; } Array sigalgs; if (!parse_sigalg_pairs(&sigalgs, values, num_values) || !sigalgs_unique(sigalgs)) { return 0; } if (!SSL_set_signing_algorithm_prefs(ssl, sigalgs.data(), sigalgs.size()) || !ssl->config->verify_sigalgs.CopyFrom(sigalgs)) { return 0; } return 1; } static bool parse_sigalgs_list(Array *out, const char *str) { // str looks like "RSA+SHA1:ECDSA+SHA256:ecdsa_secp256r1_sha256". // Count colons to give the number of output elements from any successful // parse. size_t num_elements = 1; size_t len = 0; for (const char *p = str; *p; p++) { len++; if (*p == ':') { num_elements++; } } if (!out->Init(num_elements)) { return false; } size_t out_i = 0; enum { pkey_or_name, hash_name, } state = pkey_or_name; char buf[kMaxSignatureAlgorithmNameLen]; // buf_used is always < sizeof(buf). I.e. it's always safe to write // buf[buf_used] = 0. size_t buf_used = 0; int pkey_type = 0, hash_nid = 0; // Note that the loop runs to len+1, i.e. it'll process the terminating NUL. for (size_t offset = 0; offset < len+1; offset++) { const char c = str[offset]; switch (c) { case '+': if (state == hash_name) { OPENSSL_PUT_ERROR(SSL, SSL_R_INVALID_SIGNATURE_ALGORITHM); ERR_add_error_dataf("+ found in hash name at offset %zu", offset); return false; } if (buf_used == 0) { OPENSSL_PUT_ERROR(SSL, SSL_R_INVALID_SIGNATURE_ALGORITHM); ERR_add_error_dataf("empty public key type at offset %zu", offset); return false; } buf[buf_used] = 0; if (strcmp(buf, "RSA") == 0) { pkey_type = EVP_PKEY_RSA; } else if (strcmp(buf, "RSA-PSS") == 0 || strcmp(buf, "PSS") == 0) { pkey_type = EVP_PKEY_RSA_PSS; } else if (strcmp(buf, "ECDSA") == 0) { pkey_type = EVP_PKEY_EC; } else { OPENSSL_PUT_ERROR(SSL, SSL_R_INVALID_SIGNATURE_ALGORITHM); ERR_add_error_dataf("unknown public key type '%s'", buf); return false; } state = hash_name; buf_used = 0; break; case ':': OPENSSL_FALLTHROUGH; case 0: if (buf_used == 0) { OPENSSL_PUT_ERROR(SSL, SSL_R_INVALID_SIGNATURE_ALGORITHM); ERR_add_error_dataf("empty element at offset %zu", offset); return false; } buf[buf_used] = 0; if (state == pkey_or_name) { // No '+' was seen thus this is a TLS 1.3-style name. bool found = false; for (const auto &candidate : kSignatureAlgorithmNames) { if (strcmp(candidate.name, buf) == 0) { assert(out_i < num_elements); (*out)[out_i++] = candidate.signature_algorithm; found = true; break; } } if (!found) { OPENSSL_PUT_ERROR(SSL, SSL_R_INVALID_SIGNATURE_ALGORITHM); ERR_add_error_dataf("unknown signature algorithm '%s'", buf); return false; } } else { if (strcmp(buf, "SHA1") == 0) { hash_nid = NID_sha1; } else if (strcmp(buf, "SHA256") == 0) { hash_nid = NID_sha256; } else if (strcmp(buf, "SHA384") == 0) { hash_nid = NID_sha384; } else if (strcmp(buf, "SHA512") == 0) { hash_nid = NID_sha512; } else { OPENSSL_PUT_ERROR(SSL, SSL_R_INVALID_SIGNATURE_ALGORITHM); ERR_add_error_dataf("unknown hash function '%s'", buf); return false; } bool found = false; for (const auto &candidate : kSignatureAlgorithmsMapping) { if (candidate.pkey_type == pkey_type && candidate.hash_nid == hash_nid) { assert(out_i < num_elements); (*out)[out_i++] = candidate.signature_algorithm; found = true; break; } } if (!found) { OPENSSL_PUT_ERROR(SSL, SSL_R_INVALID_SIGNATURE_ALGORITHM); ERR_add_error_dataf("unknown pkey:%d hash:%s", pkey_type, buf); return false; } } state = pkey_or_name; buf_used = 0; break; default: if (buf_used == sizeof(buf) - 1) { OPENSSL_PUT_ERROR(SSL, SSL_R_INVALID_SIGNATURE_ALGORITHM); ERR_add_error_dataf("substring too long at offset %zu", offset); return false; } if ((c >= '0' && c <= '9') || (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z') || c == '-' || c == '_') { buf[buf_used++] = c; } else { OPENSSL_PUT_ERROR(SSL, SSL_R_INVALID_SIGNATURE_ALGORITHM); ERR_add_error_dataf("invalid character 0x%02x at offest %zu", c, offset); return false; } } } assert(out_i == out->size()); return true; } int SSL_CTX_set1_sigalgs_list(SSL_CTX *ctx, const char *str) { Array sigalgs; if (!parse_sigalgs_list(&sigalgs, str) || !sigalgs_unique(sigalgs)) { return 0; } if (!SSL_CTX_set_signing_algorithm_prefs(ctx, sigalgs.data(), sigalgs.size()) || !ctx->verify_sigalgs.CopyFrom(sigalgs)) { return 0; } return 1; } int SSL_set1_sigalgs_list(SSL *ssl, const char *str) { if (!ssl->config) { OPENSSL_PUT_ERROR(SSL, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED); return 0; } Array sigalgs; if (!parse_sigalgs_list(&sigalgs, str) || !sigalgs_unique(sigalgs)) { return 0; } if (!SSL_set_signing_algorithm_prefs(ssl, sigalgs.data(), sigalgs.size()) || !ssl->config->verify_sigalgs.CopyFrom(sigalgs)) { return 0; } return 1; } int SSL_CTX_set_verify_algorithm_prefs(SSL_CTX *ctx, const uint16_t *prefs, size_t num_prefs) { return ctx->verify_sigalgs.CopyFrom(MakeConstSpan(prefs, num_prefs)); }