1 // Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved.
2 //
3 // Licensed under the Apache License, Version 2.0 (the "License");
4 // you may not use this file except in compliance with the License.
5 // You may obtain a copy of the License at
6 //
7 //     https://www.apache.org/licenses/LICENSE-2.0
8 //
9 // Unless required by applicable law or agreed to in writing, software
10 // distributed under the License is distributed on an "AS IS" BASIS,
11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 // See the License for the specific language governing permissions and
13 // limitations under the License.
14 
15 #include <openssl/ssl.h>
16 
17 #include <assert.h>
18 #include <limits.h>
19 
20 #include <algorithm>
21 
22 #include <openssl/ec.h>
23 #include <openssl/ec_key.h>
24 #include <openssl/err.h>
25 #include <openssl/evp.h>
26 #include <openssl/mem.h>
27 #include <openssl/span.h>
28 
29 #include "../crypto/internal.h"
30 #include "internal.h"
31 
32 
33 BSSL_NAMESPACE_BEGIN
34 
ssl_is_key_type_supported(int key_type)35 bool ssl_is_key_type_supported(int key_type) {
36   return key_type == EVP_PKEY_RSA || key_type == EVP_PKEY_EC ||
37          key_type == EVP_PKEY_ED25519;
38 }
39 
40 typedef struct {
41   uint16_t sigalg;
42   int pkey_type;
43   int curve;
44   const EVP_MD *(*digest_func)(void);
45   bool is_rsa_pss;
46   bool tls12_ok;
47   bool tls13_ok;
48   bool client_only;
49 } SSL_SIGNATURE_ALGORITHM;
50 
51 static const SSL_SIGNATURE_ALGORITHM kSignatureAlgorithms[] = {
52     // PKCS#1 v1.5 code points are only allowed in TLS 1.2.
53     {SSL_SIGN_RSA_PKCS1_MD5_SHA1, EVP_PKEY_RSA, NID_undef, &EVP_md5_sha1,
54      /*is_rsa_pss=*/false, /*tls12_ok=*/true, /*tls13_ok=*/false,
55      /*client_only=*/false},
56     {SSL_SIGN_RSA_PKCS1_SHA1, EVP_PKEY_RSA, NID_undef, &EVP_sha1,
57      /*is_rsa_pss=*/false, /*tls12_ok=*/true, /*tls13_ok=*/false,
58      /*client_only=*/false},
59     {SSL_SIGN_RSA_PKCS1_SHA256, EVP_PKEY_RSA, NID_undef, &EVP_sha256,
60      /*is_rsa_pss=*/false, /*tls12_ok=*/true, /*tls13_ok=*/false,
61      /*client_only=*/false},
62     {SSL_SIGN_RSA_PKCS1_SHA384, EVP_PKEY_RSA, NID_undef, &EVP_sha384,
63      /*is_rsa_pss=*/false, /*tls12_ok=*/true, /*tls13_ok=*/false,
64      /*client_only=*/false},
65     {SSL_SIGN_RSA_PKCS1_SHA512, EVP_PKEY_RSA, NID_undef, &EVP_sha512,
66      /*is_rsa_pss=*/false, /*tls12_ok=*/true, /*tls13_ok=*/false,
67      /*client_only=*/false},
68 
69     // Legacy PKCS#1 v1.5 code points are only allowed in TLS 1.3 and
70     // client-only. See draft-ietf-tls-tls13-pkcs1-00.
71     {SSL_SIGN_RSA_PKCS1_SHA256_LEGACY, EVP_PKEY_RSA, NID_undef, &EVP_sha256,
72      /*is_rsa_pss=*/false, /*tls12_ok=*/false, /*tls13_ok=*/true,
73      /*client_only=*/true},
74 
75     {SSL_SIGN_RSA_PSS_RSAE_SHA256, EVP_PKEY_RSA, NID_undef, &EVP_sha256,
76      /*is_rsa_pss=*/true, /*tls12_ok=*/true, /*tls13_ok=*/true,
77      /*client_only=*/false},
78     {SSL_SIGN_RSA_PSS_RSAE_SHA384, EVP_PKEY_RSA, NID_undef, &EVP_sha384,
79      /*is_rsa_pss=*/true, /*tls12_ok=*/true, /*tls13_ok=*/true,
80      /*client_only=*/false},
81     {SSL_SIGN_RSA_PSS_RSAE_SHA512, EVP_PKEY_RSA, NID_undef, &EVP_sha512,
82      /*is_rsa_pss=*/true, /*tls12_ok=*/true, /*tls13_ok=*/true,
83      /*client_only=*/false},
84 
85     {SSL_SIGN_ECDSA_SHA1, EVP_PKEY_EC, NID_undef, &EVP_sha1,
86      /*is_rsa_pss=*/false, /*tls12_ok=*/true, /*tls13_ok=*/false,
87      /*client_only=*/false},
88     {SSL_SIGN_ECDSA_SECP256R1_SHA256, EVP_PKEY_EC, NID_X9_62_prime256v1,
89      &EVP_sha256, /*is_rsa_pss=*/false, /*tls12_ok=*/true, /*tls13_ok=*/true,
90      /*client_only=*/false},
91     {SSL_SIGN_ECDSA_SECP384R1_SHA384, EVP_PKEY_EC, NID_secp384r1, &EVP_sha384,
92      /*is_rsa_pss=*/false, /*tls12_ok=*/true, /*tls13_ok=*/true,
93      /*client_only=*/false},
94     {SSL_SIGN_ECDSA_SECP521R1_SHA512, EVP_PKEY_EC, NID_secp521r1, &EVP_sha512,
95      /*is_rsa_pss=*/false, /*tls12_ok=*/true, /*tls13_ok=*/true,
96      /*client_only=*/false},
97 
98     {SSL_SIGN_ED25519, EVP_PKEY_ED25519, NID_undef, nullptr,
99      /*is_rsa_pss=*/false, /*tls12_ok=*/true, /*tls13_ok=*/true,
100      /*client_only=*/false},
101 };
102 
get_signature_algorithm(uint16_t sigalg)103 static const SSL_SIGNATURE_ALGORITHM *get_signature_algorithm(uint16_t sigalg) {
104   for (size_t i = 0; i < OPENSSL_ARRAY_SIZE(kSignatureAlgorithms); i++) {
105     if (kSignatureAlgorithms[i].sigalg == sigalg) {
106       return &kSignatureAlgorithms[i];
107     }
108   }
109   return NULL;
110 }
111 
ssl_pkey_supports_algorithm(const SSL * ssl,EVP_PKEY * pkey,uint16_t sigalg,bool is_verify)112 bool ssl_pkey_supports_algorithm(const SSL *ssl, EVP_PKEY *pkey,
113                                  uint16_t sigalg, bool is_verify) {
114   const SSL_SIGNATURE_ALGORITHM *alg = get_signature_algorithm(sigalg);
115   if (alg == NULL || EVP_PKEY_id(pkey) != alg->pkey_type) {
116     return false;
117   }
118 
119   // Ensure the RSA key is large enough for the hash. RSASSA-PSS requires that
120   // emLen be at least hLen + sLen + 2. Both hLen and sLen are the size of the
121   // hash in TLS. Reasonable RSA key sizes are large enough for the largest
122   // defined RSASSA-PSS algorithm, but 1024-bit RSA is slightly too small for
123   // SHA-512. 1024-bit RSA is sometimes used for test credentials, so check the
124   // size so that we can fall back to another algorithm in that case.
125   if (alg->is_rsa_pss &&
126       (size_t)EVP_PKEY_size(pkey) < 2 * EVP_MD_size(alg->digest_func()) + 2) {
127     return false;
128   }
129 
130   if (ssl_protocol_version(ssl) < TLS1_2_VERSION) {
131     // TLS 1.0 and 1.1 do not negotiate algorithms and always sign one of two
132     // hardcoded algorithms.
133     return sigalg == SSL_SIGN_RSA_PKCS1_MD5_SHA1 ||
134            sigalg == SSL_SIGN_ECDSA_SHA1;
135   }
136 
137   // |SSL_SIGN_RSA_PKCS1_MD5_SHA1| is not a real SignatureScheme for TLS 1.2 and
138   // higher. It is an internal value we use to represent TLS 1.0/1.1's MD5/SHA1
139   // concatenation.
140   if (sigalg == SSL_SIGN_RSA_PKCS1_MD5_SHA1) {
141     return false;
142   }
143 
144   if (ssl_protocol_version(ssl) >= TLS1_3_VERSION) {
145     if (!alg->tls13_ok) {
146       return false;
147     }
148 
149     bool is_client_sign = ssl->server == is_verify;
150     if (alg->client_only && !is_client_sign) {
151       return false;
152     }
153 
154     // EC keys have a curve requirement.
155     if (alg->pkey_type == EVP_PKEY_EC &&
156         (alg->curve == NID_undef ||
157          EVP_PKEY_get_ec_curve_nid(pkey) != alg->curve)) {
158       return false;
159     }
160   } else if (!alg->tls12_ok) {
161     return false;
162   }
163 
164   return true;
165 }
166 
setup_ctx(SSL * ssl,EVP_MD_CTX * ctx,EVP_PKEY * pkey,uint16_t sigalg,bool is_verify)167 static bool setup_ctx(SSL *ssl, EVP_MD_CTX *ctx, EVP_PKEY *pkey,
168                       uint16_t sigalg, bool is_verify) {
169   if (!ssl_pkey_supports_algorithm(ssl, pkey, sigalg, is_verify)) {
170     OPENSSL_PUT_ERROR(SSL, SSL_R_WRONG_SIGNATURE_TYPE);
171     return false;
172   }
173 
174   const SSL_SIGNATURE_ALGORITHM *alg = get_signature_algorithm(sigalg);
175   const EVP_MD *digest = alg->digest_func != NULL ? alg->digest_func() : NULL;
176   EVP_PKEY_CTX *pctx;
177   if (is_verify) {
178     if (!EVP_DigestVerifyInit(ctx, &pctx, digest, NULL, pkey)) {
179       return false;
180     }
181   } else if (!EVP_DigestSignInit(ctx, &pctx, digest, NULL, pkey)) {
182     return false;
183   }
184 
185   if (alg->is_rsa_pss) {
186     if (!EVP_PKEY_CTX_set_rsa_padding(pctx, RSA_PKCS1_PSS_PADDING) ||
187         !EVP_PKEY_CTX_set_rsa_pss_saltlen(pctx, RSA_PSS_SALTLEN_DIGEST)) {
188       return false;
189     }
190   }
191 
192   return true;
193 }
194 
ssl_private_key_sign(SSL_HANDSHAKE * hs,uint8_t * out,size_t * out_len,size_t max_out,uint16_t sigalg,Span<const uint8_t> in)195 enum ssl_private_key_result_t ssl_private_key_sign(
196     SSL_HANDSHAKE *hs, uint8_t *out, size_t *out_len, size_t max_out,
197     uint16_t sigalg, Span<const uint8_t> in) {
198   SSL *const ssl = hs->ssl;
199   const SSL_CREDENTIAL *const cred = hs->credential.get();
200   SSL_HANDSHAKE_HINTS *const hints = hs->hints.get();
201   Array<uint8_t> spki;
202   if (hints) {
203     ScopedCBB spki_cbb;
204     if (!CBB_init(spki_cbb.get(), 64) ||
205         !EVP_marshal_public_key(spki_cbb.get(), cred->pubkey.get()) ||
206         !CBBFinishArray(spki_cbb.get(), &spki)) {
207       ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
208       return ssl_private_key_failure;
209     }
210   }
211 
212   // Replay the signature from handshake hints if available.
213   if (hints && !hs->hints_requested &&         //
214       sigalg == hints->signature_algorithm &&  //
215       in == hints->signature_input &&          //
216       Span(spki) == hints->signature_spki &&   //
217       !hints->signature.empty() &&             //
218       hints->signature.size() <= max_out) {
219     // Signature algorithm and input both match. Reuse the signature from hints.
220     *out_len = hints->signature.size();
221     OPENSSL_memcpy(out, hints->signature.data(), hints->signature.size());
222     return ssl_private_key_success;
223   }
224 
225   const SSL_PRIVATE_KEY_METHOD *key_method = cred->key_method;
226   EVP_PKEY *privkey = cred->privkey.get();
227   assert(!hs->can_release_private_key);
228 
229   if (key_method != NULL) {
230     enum ssl_private_key_result_t ret;
231     if (hs->pending_private_key_op) {
232       ret = key_method->complete(ssl, out, out_len, max_out);
233     } else {
234       ret = key_method->sign(ssl, out, out_len, max_out, sigalg, in.data(),
235                              in.size());
236     }
237     if (ret == ssl_private_key_failure) {
238       OPENSSL_PUT_ERROR(SSL, SSL_R_PRIVATE_KEY_OPERATION_FAILED);
239     }
240     hs->pending_private_key_op = ret == ssl_private_key_retry;
241     if (ret != ssl_private_key_success) {
242       return ret;
243     }
244   } else {
245     *out_len = max_out;
246     ScopedEVP_MD_CTX ctx;
247     if (!setup_ctx(ssl, ctx.get(), privkey, sigalg, false /* sign */) ||
248         !EVP_DigestSign(ctx.get(), out, out_len, in.data(), in.size())) {
249       return ssl_private_key_failure;
250     }
251   }
252 
253   // Save the hint if applicable.
254   if (hints && hs->hints_requested) {
255     hints->signature_algorithm = sigalg;
256     hints->signature_spki = std::move(spki);
257     if (!hints->signature_input.CopyFrom(in) ||
258         !hints->signature.CopyFrom(Span(out, *out_len))) {
259       return ssl_private_key_failure;
260     }
261   }
262   return ssl_private_key_success;
263 }
264 
ssl_public_key_verify(SSL * ssl,Span<const uint8_t> signature,uint16_t sigalg,EVP_PKEY * pkey,Span<const uint8_t> in)265 bool ssl_public_key_verify(SSL *ssl, Span<const uint8_t> signature,
266                            uint16_t sigalg, EVP_PKEY *pkey,
267                            Span<const uint8_t> in) {
268   ScopedEVP_MD_CTX ctx;
269   if (!setup_ctx(ssl, ctx.get(), pkey, sigalg, true /* verify */)) {
270     return false;
271   }
272   bool ok = EVP_DigestVerify(ctx.get(), signature.data(), signature.size(),
273                              in.data(), in.size());
274   if (CRYPTO_fuzzer_mode_enabled()) {
275     ok = true;
276     ERR_clear_error();
277   }
278   return ok;
279 }
280 
ssl_private_key_decrypt(SSL_HANDSHAKE * hs,uint8_t * out,size_t * out_len,size_t max_out,Span<const uint8_t> in)281 enum ssl_private_key_result_t ssl_private_key_decrypt(SSL_HANDSHAKE *hs,
282                                                       uint8_t *out,
283                                                       size_t *out_len,
284                                                       size_t max_out,
285                                                       Span<const uint8_t> in) {
286   SSL *const ssl = hs->ssl;
287   const SSL_CREDENTIAL *const cred = hs->credential.get();
288   assert(!hs->can_release_private_key);
289   if (cred->key_method != NULL) {
290     enum ssl_private_key_result_t ret;
291     if (hs->pending_private_key_op) {
292       ret = cred->key_method->complete(ssl, out, out_len, max_out);
293     } else {
294       ret = cred->key_method->decrypt(ssl, out, out_len, max_out, in.data(),
295                                       in.size());
296     }
297     if (ret == ssl_private_key_failure) {
298       OPENSSL_PUT_ERROR(SSL, SSL_R_PRIVATE_KEY_OPERATION_FAILED);
299     }
300     hs->pending_private_key_op = ret == ssl_private_key_retry;
301     return ret;
302   }
303 
304   RSA *rsa = EVP_PKEY_get0_RSA(cred->privkey.get());
305   if (rsa == NULL) {
306     // Decrypt operations are only supported for RSA keys.
307     OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
308     return ssl_private_key_failure;
309   }
310 
311   // Decrypt with no padding. PKCS#1 padding will be removed as part of the
312   // timing-sensitive code by the caller.
313   if (!RSA_decrypt(rsa, out_len, out, max_out, in.data(), in.size(),
314                    RSA_NO_PADDING)) {
315     return ssl_private_key_failure;
316   }
317   return ssl_private_key_success;
318 }
319 
320 BSSL_NAMESPACE_END
321 
322 using namespace bssl;
323 
SSL_use_RSAPrivateKey(SSL * ssl,RSA * rsa)324 int SSL_use_RSAPrivateKey(SSL *ssl, RSA *rsa) {
325   if (rsa == NULL || ssl->config == NULL) {
326     OPENSSL_PUT_ERROR(SSL, ERR_R_PASSED_NULL_PARAMETER);
327     return 0;
328   }
329 
330   UniquePtr<EVP_PKEY> pkey(EVP_PKEY_new());
331   if (!pkey ||  //
332       !EVP_PKEY_set1_RSA(pkey.get(), rsa)) {
333     OPENSSL_PUT_ERROR(SSL, ERR_R_EVP_LIB);
334     return 0;
335   }
336 
337   return SSL_use_PrivateKey(ssl, pkey.get());
338 }
339 
SSL_use_RSAPrivateKey_ASN1(SSL * ssl,const uint8_t * der,size_t der_len)340 int SSL_use_RSAPrivateKey_ASN1(SSL *ssl, const uint8_t *der, size_t der_len) {
341   UniquePtr<RSA> rsa(RSA_private_key_from_bytes(der, der_len));
342   if (!rsa) {
343     OPENSSL_PUT_ERROR(SSL, ERR_R_ASN1_LIB);
344     return 0;
345   }
346 
347   return SSL_use_RSAPrivateKey(ssl, rsa.get());
348 }
349 
SSL_use_PrivateKey(SSL * ssl,EVP_PKEY * pkey)350 int SSL_use_PrivateKey(SSL *ssl, EVP_PKEY *pkey) {
351   if (pkey == NULL || ssl->config == NULL) {
352     OPENSSL_PUT_ERROR(SSL, ERR_R_PASSED_NULL_PARAMETER);
353     return 0;
354   }
355 
356   return SSL_CREDENTIAL_set1_private_key(
357       ssl->config->cert->legacy_credential.get(), pkey);
358 }
359 
SSL_use_PrivateKey_ASN1(int type,SSL * ssl,const uint8_t * der,size_t der_len)360 int SSL_use_PrivateKey_ASN1(int type, SSL *ssl, const uint8_t *der,
361                             size_t der_len) {
362   if (der_len > LONG_MAX) {
363     OPENSSL_PUT_ERROR(SSL, ERR_R_OVERFLOW);
364     return 0;
365   }
366 
367   const uint8_t *p = der;
368   UniquePtr<EVP_PKEY> pkey(d2i_PrivateKey(type, NULL, &p, (long)der_len));
369   if (!pkey || p != der + der_len) {
370     OPENSSL_PUT_ERROR(SSL, ERR_R_ASN1_LIB);
371     return 0;
372   }
373 
374   return SSL_use_PrivateKey(ssl, pkey.get());
375 }
376 
SSL_CTX_use_RSAPrivateKey(SSL_CTX * ctx,RSA * rsa)377 int SSL_CTX_use_RSAPrivateKey(SSL_CTX *ctx, RSA *rsa) {
378   if (rsa == NULL) {
379     OPENSSL_PUT_ERROR(SSL, ERR_R_PASSED_NULL_PARAMETER);
380     return 0;
381   }
382 
383   UniquePtr<EVP_PKEY> pkey(EVP_PKEY_new());
384   if (!pkey || !EVP_PKEY_set1_RSA(pkey.get(), rsa)) {
385     OPENSSL_PUT_ERROR(SSL, ERR_R_EVP_LIB);
386     return 0;
387   }
388 
389   return SSL_CTX_use_PrivateKey(ctx, pkey.get());
390 }
391 
SSL_CTX_use_RSAPrivateKey_ASN1(SSL_CTX * ctx,const uint8_t * der,size_t der_len)392 int SSL_CTX_use_RSAPrivateKey_ASN1(SSL_CTX *ctx, const uint8_t *der,
393                                    size_t der_len) {
394   UniquePtr<RSA> rsa(RSA_private_key_from_bytes(der, der_len));
395   if (!rsa) {
396     OPENSSL_PUT_ERROR(SSL, ERR_R_ASN1_LIB);
397     return 0;
398   }
399 
400   return SSL_CTX_use_RSAPrivateKey(ctx, rsa.get());
401 }
402 
SSL_CTX_use_PrivateKey(SSL_CTX * ctx,EVP_PKEY * pkey)403 int SSL_CTX_use_PrivateKey(SSL_CTX *ctx, EVP_PKEY *pkey) {
404   if (pkey == NULL) {
405     OPENSSL_PUT_ERROR(SSL, ERR_R_PASSED_NULL_PARAMETER);
406     return 0;
407   }
408 
409   return SSL_CREDENTIAL_set1_private_key(ctx->cert->legacy_credential.get(),
410                                          pkey);
411 }
412 
SSL_CTX_use_PrivateKey_ASN1(int type,SSL_CTX * ctx,const uint8_t * der,size_t der_len)413 int SSL_CTX_use_PrivateKey_ASN1(int type, SSL_CTX *ctx, const uint8_t *der,
414                                 size_t der_len) {
415   if (der_len > LONG_MAX) {
416     OPENSSL_PUT_ERROR(SSL, ERR_R_OVERFLOW);
417     return 0;
418   }
419 
420   const uint8_t *p = der;
421   UniquePtr<EVP_PKEY> pkey(d2i_PrivateKey(type, NULL, &p, (long)der_len));
422   if (!pkey || p != der + der_len) {
423     OPENSSL_PUT_ERROR(SSL, ERR_R_ASN1_LIB);
424     return 0;
425   }
426 
427   return SSL_CTX_use_PrivateKey(ctx, pkey.get());
428 }
429 
SSL_set_private_key_method(SSL * ssl,const SSL_PRIVATE_KEY_METHOD * key_method)430 void SSL_set_private_key_method(SSL *ssl,
431                                 const SSL_PRIVATE_KEY_METHOD *key_method) {
432   if (!ssl->config) {
433     return;
434   }
435   BSSL_CHECK(SSL_CREDENTIAL_set_private_key_method(
436       ssl->config->cert->legacy_credential.get(), key_method));
437 }
438 
SSL_CTX_set_private_key_method(SSL_CTX * ctx,const SSL_PRIVATE_KEY_METHOD * key_method)439 void SSL_CTX_set_private_key_method(SSL_CTX *ctx,
440                                     const SSL_PRIVATE_KEY_METHOD *key_method) {
441   BSSL_CHECK(SSL_CREDENTIAL_set_private_key_method(
442       ctx->cert->legacy_credential.get(), key_method));
443 }
444 
445 static constexpr size_t kMaxSignatureAlgorithmNameLen = 24;
446 
447 struct SignatureAlgorithmName {
448   uint16_t signature_algorithm;
449   const char name[kMaxSignatureAlgorithmNameLen];
450 };
451 
452 // This was "constexpr" rather than "const", but that triggered a bug in MSVC
453 // where it didn't pad the strings to the correct length.
454 static const SignatureAlgorithmName kSignatureAlgorithmNames[] = {
455     {SSL_SIGN_RSA_PKCS1_MD5_SHA1, "rsa_pkcs1_md5_sha1"},
456     {SSL_SIGN_RSA_PKCS1_SHA1, "rsa_pkcs1_sha1"},
457     {SSL_SIGN_RSA_PKCS1_SHA256, "rsa_pkcs1_sha256"},
458     {SSL_SIGN_RSA_PKCS1_SHA256_LEGACY, "rsa_pkcs1_sha256_legacy"},
459     {SSL_SIGN_RSA_PKCS1_SHA384, "rsa_pkcs1_sha384"},
460     {SSL_SIGN_RSA_PKCS1_SHA512, "rsa_pkcs1_sha512"},
461     {SSL_SIGN_ECDSA_SHA1, "ecdsa_sha1"},
462     {SSL_SIGN_ECDSA_SECP256R1_SHA256, "ecdsa_secp256r1_sha256"},
463     {SSL_SIGN_ECDSA_SECP384R1_SHA384, "ecdsa_secp384r1_sha384"},
464     {SSL_SIGN_ECDSA_SECP521R1_SHA512, "ecdsa_secp521r1_sha512"},
465     {SSL_SIGN_RSA_PSS_RSAE_SHA256, "rsa_pss_rsae_sha256"},
466     {SSL_SIGN_RSA_PSS_RSAE_SHA384, "rsa_pss_rsae_sha384"},
467     {SSL_SIGN_RSA_PSS_RSAE_SHA512, "rsa_pss_rsae_sha512"},
468     {SSL_SIGN_ED25519, "ed25519"},
469 };
470 
SSL_get_signature_algorithm_name(uint16_t sigalg,int include_curve)471 const char *SSL_get_signature_algorithm_name(uint16_t sigalg,
472                                              int include_curve) {
473   if (!include_curve) {
474     switch (sigalg) {
475       case SSL_SIGN_ECDSA_SECP256R1_SHA256:
476         return "ecdsa_sha256";
477       case SSL_SIGN_ECDSA_SECP384R1_SHA384:
478         return "ecdsa_sha384";
479       case SSL_SIGN_ECDSA_SECP521R1_SHA512:
480         return "ecdsa_sha512";
481         // If adding more here, also update
482         // |SSL_get_all_signature_algorithm_names|.
483     }
484   }
485 
486   for (const auto &candidate : kSignatureAlgorithmNames) {
487     if (candidate.signature_algorithm == sigalg) {
488       return candidate.name;
489     }
490   }
491 
492   return NULL;
493 }
494 
SSL_get_all_signature_algorithm_names(const char ** out,size_t max_out)495 size_t SSL_get_all_signature_algorithm_names(const char **out, size_t max_out) {
496   const char *kPredefinedNames[] = {"ecdsa_sha256", "ecdsa_sha384",
497                                     "ecdsa_sha512"};
498   return GetAllNames(out, max_out, kPredefinedNames,
499                      &SignatureAlgorithmName::name,
500                      Span(kSignatureAlgorithmNames));
501 }
502 
SSL_get_signature_algorithm_key_type(uint16_t sigalg)503 int SSL_get_signature_algorithm_key_type(uint16_t sigalg) {
504   const SSL_SIGNATURE_ALGORITHM *alg = get_signature_algorithm(sigalg);
505   return alg != nullptr ? alg->pkey_type : EVP_PKEY_NONE;
506 }
507 
SSL_get_signature_algorithm_digest(uint16_t sigalg)508 const EVP_MD *SSL_get_signature_algorithm_digest(uint16_t sigalg) {
509   const SSL_SIGNATURE_ALGORITHM *alg = get_signature_algorithm(sigalg);
510   if (alg == nullptr || alg->digest_func == nullptr) {
511     return nullptr;
512   }
513   return alg->digest_func();
514 }
515 
SSL_is_signature_algorithm_rsa_pss(uint16_t sigalg)516 int SSL_is_signature_algorithm_rsa_pss(uint16_t sigalg) {
517   const SSL_SIGNATURE_ALGORITHM *alg = get_signature_algorithm(sigalg);
518   return alg != nullptr && alg->is_rsa_pss;
519 }
520 
sigalgs_unique(Span<const uint16_t> in_sigalgs)521 static bool sigalgs_unique(Span<const uint16_t> in_sigalgs) {
522   if (in_sigalgs.size() < 2) {
523     return true;
524   }
525 
526   Array<uint16_t> sigalgs;
527   if (!sigalgs.CopyFrom(in_sigalgs)) {
528     return false;
529   }
530 
531   std::sort(sigalgs.begin(), sigalgs.end());
532   for (size_t i = 1; i < sigalgs.size(); i++) {
533     if (sigalgs[i - 1] == sigalgs[i]) {
534       OPENSSL_PUT_ERROR(SSL, SSL_R_DUPLICATE_SIGNATURE_ALGORITHM);
535       return false;
536     }
537   }
538 
539   return true;
540 }
541 
set_sigalg_prefs(Array<uint16_t> * out,Span<const uint16_t> prefs)542 static bool set_sigalg_prefs(Array<uint16_t> *out, Span<const uint16_t> prefs) {
543   if (!sigalgs_unique(prefs)) {
544     return false;
545   }
546 
547   // Check for invalid algorithms, and filter out |SSL_SIGN_RSA_PKCS1_MD5_SHA1|.
548   Array<uint16_t> filtered;
549   if (!filtered.InitForOverwrite(prefs.size())) {
550     return false;
551   }
552   size_t added = 0;
553   for (uint16_t pref : prefs) {
554     if (pref == SSL_SIGN_RSA_PKCS1_MD5_SHA1) {
555       // Though not intended to be used with this API, we treat
556       // |SSL_SIGN_RSA_PKCS1_MD5_SHA1| as a real signature algorithm in
557       // |SSL_PRIVATE_KEY_METHOD|. Not accepting it here makes for a confusing
558       // abstraction.
559       continue;
560     }
561     if (get_signature_algorithm(pref) == nullptr) {
562       OPENSSL_PUT_ERROR(SSL, SSL_R_INVALID_SIGNATURE_ALGORITHM);
563       return false;
564     }
565     filtered[added] = pref;
566     added++;
567   }
568   filtered.Shrink(added);
569 
570   // This can happen if |prefs| contained only |SSL_SIGN_RSA_PKCS1_MD5_SHA1|.
571   // Leaving it empty would revert to the default, so treat this as an error
572   // condition.
573   if (!prefs.empty() && filtered.empty()) {
574     OPENSSL_PUT_ERROR(SSL, SSL_R_INVALID_SIGNATURE_ALGORITHM);
575     return false;
576   }
577 
578   *out = std::move(filtered);
579   return true;
580 }
581 
SSL_CREDENTIAL_set1_signing_algorithm_prefs(SSL_CREDENTIAL * cred,const uint16_t * prefs,size_t num_prefs)582 int SSL_CREDENTIAL_set1_signing_algorithm_prefs(SSL_CREDENTIAL *cred,
583                                                 const uint16_t *prefs,
584                                                 size_t num_prefs) {
585   if (!cred->UsesPrivateKey()) {
586     OPENSSL_PUT_ERROR(SSL, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
587     return 0;
588   }
589 
590   // Delegated credentials are constrained to a single algorithm, so there is no
591   // need to configure this.
592   if (cred->type == SSLCredentialType::kDelegated) {
593     OPENSSL_PUT_ERROR(SSL, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
594     return 0;
595   }
596 
597   return set_sigalg_prefs(&cred->sigalgs, Span(prefs, num_prefs));
598 }
599 
SSL_CTX_set_signing_algorithm_prefs(SSL_CTX * ctx,const uint16_t * prefs,size_t num_prefs)600 int SSL_CTX_set_signing_algorithm_prefs(SSL_CTX *ctx, const uint16_t *prefs,
601                                         size_t num_prefs) {
602   return SSL_CREDENTIAL_set1_signing_algorithm_prefs(
603       ctx->cert->legacy_credential.get(), prefs, num_prefs);
604 }
605 
SSL_set_signing_algorithm_prefs(SSL * ssl,const uint16_t * prefs,size_t num_prefs)606 int SSL_set_signing_algorithm_prefs(SSL *ssl, const uint16_t *prefs,
607                                     size_t num_prefs) {
608   if (!ssl->config) {
609     return 0;
610   }
611   return SSL_CREDENTIAL_set1_signing_algorithm_prefs(
612       ssl->config->cert->legacy_credential.get(), prefs, num_prefs);
613 }
614 
615 static constexpr struct {
616   int pkey_type;
617   int hash_nid;
618   uint16_t signature_algorithm;
619 } kSignatureAlgorithmsMapping[] = {
620     {EVP_PKEY_RSA, NID_sha1, SSL_SIGN_RSA_PKCS1_SHA1},
621     {EVP_PKEY_RSA, NID_sha256, SSL_SIGN_RSA_PKCS1_SHA256},
622     {EVP_PKEY_RSA, NID_sha384, SSL_SIGN_RSA_PKCS1_SHA384},
623     {EVP_PKEY_RSA, NID_sha512, SSL_SIGN_RSA_PKCS1_SHA512},
624     {EVP_PKEY_RSA_PSS, NID_sha256, SSL_SIGN_RSA_PSS_RSAE_SHA256},
625     {EVP_PKEY_RSA_PSS, NID_sha384, SSL_SIGN_RSA_PSS_RSAE_SHA384},
626     {EVP_PKEY_RSA_PSS, NID_sha512, SSL_SIGN_RSA_PSS_RSAE_SHA512},
627     {EVP_PKEY_EC, NID_sha1, SSL_SIGN_ECDSA_SHA1},
628     {EVP_PKEY_EC, NID_sha256, SSL_SIGN_ECDSA_SECP256R1_SHA256},
629     {EVP_PKEY_EC, NID_sha384, SSL_SIGN_ECDSA_SECP384R1_SHA384},
630     {EVP_PKEY_EC, NID_sha512, SSL_SIGN_ECDSA_SECP521R1_SHA512},
631     {EVP_PKEY_ED25519, NID_undef, SSL_SIGN_ED25519},
632 };
633 
parse_sigalg_pairs(Array<uint16_t> * out,const int * values,size_t num_values)634 static bool parse_sigalg_pairs(Array<uint16_t> *out, const int *values,
635                                size_t num_values) {
636   if ((num_values & 1) == 1) {
637     return false;
638   }
639 
640   const size_t num_pairs = num_values / 2;
641   if (!out->InitForOverwrite(num_pairs)) {
642     return false;
643   }
644 
645   for (size_t i = 0; i < num_values; i += 2) {
646     const int hash_nid = values[i];
647     const int pkey_type = values[i + 1];
648 
649     bool found = false;
650     for (const auto &candidate : kSignatureAlgorithmsMapping) {
651       if (candidate.pkey_type == pkey_type && candidate.hash_nid == hash_nid) {
652         (*out)[i / 2] = candidate.signature_algorithm;
653         found = true;
654         break;
655       }
656     }
657 
658     if (!found) {
659       OPENSSL_PUT_ERROR(SSL, SSL_R_INVALID_SIGNATURE_ALGORITHM);
660       ERR_add_error_dataf("unknown hash:%d pkey:%d", hash_nid, pkey_type);
661       return false;
662     }
663   }
664 
665   return true;
666 }
667 
SSL_CTX_set1_sigalgs(SSL_CTX * ctx,const int * values,size_t num_values)668 int SSL_CTX_set1_sigalgs(SSL_CTX *ctx, const int *values, size_t num_values) {
669   Array<uint16_t> sigalgs;
670   if (!parse_sigalg_pairs(&sigalgs, values, num_values)) {
671     return 0;
672   }
673 
674   if (!SSL_CTX_set_signing_algorithm_prefs(ctx, sigalgs.data(),
675                                            sigalgs.size()) ||
676       !SSL_CTX_set_verify_algorithm_prefs(ctx, sigalgs.data(),
677                                           sigalgs.size())) {
678     return 0;
679   }
680 
681   return 1;
682 }
683 
SSL_set1_sigalgs(SSL * ssl,const int * values,size_t num_values)684 int SSL_set1_sigalgs(SSL *ssl, const int *values, size_t num_values) {
685   if (!ssl->config) {
686     OPENSSL_PUT_ERROR(SSL, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
687     return 0;
688   }
689 
690   Array<uint16_t> sigalgs;
691   if (!parse_sigalg_pairs(&sigalgs, values, num_values)) {
692     return 0;
693   }
694 
695   if (!SSL_set_signing_algorithm_prefs(ssl, sigalgs.data(), sigalgs.size()) ||
696       !SSL_set_verify_algorithm_prefs(ssl, sigalgs.data(), sigalgs.size())) {
697     return 0;
698   }
699 
700   return 1;
701 }
702 
parse_sigalgs_list(Array<uint16_t> * out,const char * str)703 static bool parse_sigalgs_list(Array<uint16_t> *out, const char *str) {
704   // str looks like "RSA+SHA1:ECDSA+SHA256:ecdsa_secp256r1_sha256".
705 
706   // Count colons to give the number of output elements from any successful
707   // parse.
708   size_t num_elements = 1;
709   size_t len = 0;
710   for (const char *p = str; *p; p++) {
711     len++;
712     if (*p == ':') {
713       num_elements++;
714     }
715   }
716 
717   if (!out->InitForOverwrite(num_elements)) {
718     return false;
719   }
720   size_t out_i = 0;
721 
722   enum {
723     pkey_or_name,
724     hash_name,
725   } state = pkey_or_name;
726 
727   char buf[kMaxSignatureAlgorithmNameLen];
728   // buf_used is always < sizeof(buf). I.e. it's always safe to write
729   // buf[buf_used] = 0.
730   size_t buf_used = 0;
731 
732   int pkey_type = 0, hash_nid = 0;
733 
734   // Note that the loop runs to len+1, i.e. it'll process the terminating NUL.
735   for (size_t offset = 0; offset < len + 1; offset++) {
736     const unsigned char c = str[offset];
737 
738     switch (c) {
739       case '+':
740         if (state == hash_name) {
741           OPENSSL_PUT_ERROR(SSL, SSL_R_INVALID_SIGNATURE_ALGORITHM);
742           ERR_add_error_dataf("+ found in hash name at offset %zu", offset);
743           return false;
744         }
745         if (buf_used == 0) {
746           OPENSSL_PUT_ERROR(SSL, SSL_R_INVALID_SIGNATURE_ALGORITHM);
747           ERR_add_error_dataf("empty public key type at offset %zu", offset);
748           return false;
749         }
750         buf[buf_used] = 0;
751 
752         if (strcmp(buf, "RSA") == 0) {
753           pkey_type = EVP_PKEY_RSA;
754         } else if (strcmp(buf, "RSA-PSS") == 0 ||  //
755                    strcmp(buf, "PSS") == 0) {
756           pkey_type = EVP_PKEY_RSA_PSS;
757         } else if (strcmp(buf, "ECDSA") == 0) {
758           pkey_type = EVP_PKEY_EC;
759         } else {
760           OPENSSL_PUT_ERROR(SSL, SSL_R_INVALID_SIGNATURE_ALGORITHM);
761           ERR_add_error_dataf("unknown public key type '%s'", buf);
762           return false;
763         }
764 
765         state = hash_name;
766         buf_used = 0;
767         break;
768 
769       case ':':
770         [[fallthrough]];
771       case 0:
772         if (buf_used == 0) {
773           OPENSSL_PUT_ERROR(SSL, SSL_R_INVALID_SIGNATURE_ALGORITHM);
774           ERR_add_error_dataf("empty element at offset %zu", offset);
775           return false;
776         }
777 
778         buf[buf_used] = 0;
779 
780         if (state == pkey_or_name) {
781           // No '+' was seen thus this is a TLS 1.3-style name.
782           bool found = false;
783           for (const auto &candidate : kSignatureAlgorithmNames) {
784             if (strcmp(candidate.name, buf) == 0) {
785               assert(out_i < num_elements);
786               (*out)[out_i++] = candidate.signature_algorithm;
787               found = true;
788               break;
789             }
790           }
791 
792           if (!found) {
793             OPENSSL_PUT_ERROR(SSL, SSL_R_INVALID_SIGNATURE_ALGORITHM);
794             ERR_add_error_dataf("unknown signature algorithm '%s'", buf);
795             return false;
796           }
797         } else {
798           if (strcmp(buf, "SHA1") == 0) {
799             hash_nid = NID_sha1;
800           } else if (strcmp(buf, "SHA256") == 0) {
801             hash_nid = NID_sha256;
802           } else if (strcmp(buf, "SHA384") == 0) {
803             hash_nid = NID_sha384;
804           } else if (strcmp(buf, "SHA512") == 0) {
805             hash_nid = NID_sha512;
806           } else {
807             OPENSSL_PUT_ERROR(SSL, SSL_R_INVALID_SIGNATURE_ALGORITHM);
808             ERR_add_error_dataf("unknown hash function '%s'", buf);
809             return false;
810           }
811 
812           bool found = false;
813           for (const auto &candidate : kSignatureAlgorithmsMapping) {
814             if (candidate.pkey_type == pkey_type &&
815                 candidate.hash_nid == hash_nid) {
816               assert(out_i < num_elements);
817               (*out)[out_i++] = candidate.signature_algorithm;
818               found = true;
819               break;
820             }
821           }
822 
823           if (!found) {
824             OPENSSL_PUT_ERROR(SSL, SSL_R_INVALID_SIGNATURE_ALGORITHM);
825             ERR_add_error_dataf("unknown pkey:%d hash:%s", pkey_type, buf);
826             return false;
827           }
828         }
829 
830         state = pkey_or_name;
831         buf_used = 0;
832         break;
833 
834       default:
835         if (buf_used == sizeof(buf) - 1) {
836           OPENSSL_PUT_ERROR(SSL, SSL_R_INVALID_SIGNATURE_ALGORITHM);
837           ERR_add_error_dataf("substring too long at offset %zu", offset);
838           return false;
839         }
840 
841         if (OPENSSL_isalnum(c) || c == '-' || c == '_') {
842           buf[buf_used++] = c;
843         } else {
844           OPENSSL_PUT_ERROR(SSL, SSL_R_INVALID_SIGNATURE_ALGORITHM);
845           ERR_add_error_dataf("invalid character 0x%02x at offest %zu", c,
846                               offset);
847           return false;
848         }
849     }
850   }
851 
852   assert(out_i == out->size());
853   return true;
854 }
855 
SSL_CTX_set1_sigalgs_list(SSL_CTX * ctx,const char * str)856 int SSL_CTX_set1_sigalgs_list(SSL_CTX *ctx, const char *str) {
857   Array<uint16_t> sigalgs;
858   if (!parse_sigalgs_list(&sigalgs, str)) {
859     return 0;
860   }
861 
862   if (!SSL_CTX_set_signing_algorithm_prefs(ctx, sigalgs.data(),
863                                            sigalgs.size()) ||
864       !SSL_CTX_set_verify_algorithm_prefs(ctx, sigalgs.data(),
865                                           sigalgs.size())) {
866     return 0;
867   }
868 
869   return 1;
870 }
871 
SSL_set1_sigalgs_list(SSL * ssl,const char * str)872 int SSL_set1_sigalgs_list(SSL *ssl, const char *str) {
873   if (!ssl->config) {
874     OPENSSL_PUT_ERROR(SSL, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
875     return 0;
876   }
877 
878   Array<uint16_t> sigalgs;
879   if (!parse_sigalgs_list(&sigalgs, str)) {
880     return 0;
881   }
882 
883   if (!SSL_set_signing_algorithm_prefs(ssl, sigalgs.data(), sigalgs.size()) ||
884       !SSL_set_verify_algorithm_prefs(ssl, sigalgs.data(), sigalgs.size())) {
885     return 0;
886   }
887 
888   return 1;
889 }
890 
SSL_CTX_set_verify_algorithm_prefs(SSL_CTX * ctx,const uint16_t * prefs,size_t num_prefs)891 int SSL_CTX_set_verify_algorithm_prefs(SSL_CTX *ctx, const uint16_t *prefs,
892                                        size_t num_prefs) {
893   return set_sigalg_prefs(&ctx->verify_sigalgs, Span(prefs, num_prefs));
894 }
895 
SSL_set_verify_algorithm_prefs(SSL * ssl,const uint16_t * prefs,size_t num_prefs)896 int SSL_set_verify_algorithm_prefs(SSL *ssl, const uint16_t *prefs,
897                                    size_t num_prefs) {
898   if (!ssl->config) {
899     OPENSSL_PUT_ERROR(SSL, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
900     return 0;
901   }
902 
903   return set_sigalg_prefs(&ssl->config->verify_sigalgs, Span(prefs, num_prefs));
904 }
905