Add CTR-DRBG.

This isn't actually used yet, but implements CTR-DRBG from SP 800-90Ar1.
Specifically, it always uses AES-256 and no derivation function.

Change-Id: Ie82b829590226addd7c165eac410a5d584858bfd
Reviewed-on: https://boringssl-review.googlesource.com/14891
Reviewed-by: Adam Langley <agl@google.com>

crypto/CMakeLists.txt

@@ -245,6 +245,7 @@ add_executable(
   ec/ec_test.cc
   err/err_test.cc
   evp/evp_extra_test.cc
+  rand/ctrdrbg_test.cc
   rsa/rsa_test.cc
 
   $<TARGET_OBJECTS:gtest_main>

crypto/rand/CMakeLists.txt

@@ -13,6 +13,7 @@ add_library(
 
   OBJECT
 
+  ctrdrbg.c
   deterministic.c
   fuchsia.c
   rand.c
@@ -23,3 +24,14 @@ add_library(
 )
 
 perlasm(rdrand-x86_64.${ASM_EXT} asm/rdrand-x86_64.pl)
+
+add_executable(
+  ctrdrbg_vector_test
+
+  ctrdrbg_vector_test.cc
+
+  $<TARGET_OBJECTS:test_support>
+)
+
+target_link_libraries(ctrdrbg_vector_test crypto)
+add_dependencies(all_tests ctrdrbg_vector_test)

crypto/rand/ctrdrbg.c

@@ -0,0 +1,200 @@
+/* Copyright (c) 2017, Google Inc.
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
+ * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
+ * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+ * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
+
+#include <openssl/rand.h>
+
+#include <openssl/type_check.h>
+#include <openssl/mem.h>
+
+#include "internal.h"
+#include "../cipher/internal.h"
+
+
+/* Section references in this file refer to SP 800-90Ar1:
+ * http://nvlpubs.nist.gov/nistpubs/SpecialPublications/NIST.SP.800-90Ar1.pdf */
+
+/* See table 3. */
+static const uint64_t kMaxReseedCount = UINT64_C(1) << 48;
+
+int CTR_DRBG_init(CTR_DRBG_STATE *drbg,
+                  const uint8_t entropy[CTR_DRBG_ENTROPY_LEN],
+                  const uint8_t *personalization, size_t personalization_len) {
+  /* Section 10.2.1.3.1 */
+  if (personalization_len > CTR_DRBG_ENTROPY_LEN) {
+    return 0;
+  }
+
+  uint8_t seed_material[CTR_DRBG_ENTROPY_LEN];
+  OPENSSL_memcpy(seed_material, entropy, CTR_DRBG_ENTROPY_LEN);
+
+  for (size_t i = 0; i < personalization_len; i++) {
+    seed_material[i] ^= personalization[i];
+  }
+
+  /* Section 10.2.1.2 */
+
+  /* kInitMask is the result of encrypting blocks with big-endian value 1, 2
+   * and 3 with the all-zero AES-256 key. */
+  static const uint8_t kInitMask[CTR_DRBG_ENTROPY_LEN] = {
+      0x53, 0x0f, 0x8a, 0xfb, 0xc7, 0x45, 0x36, 0xb9, 0xa9, 0x63, 0xb4, 0xf1,
+      0xc4, 0xcb, 0x73, 0x8b, 0xce, 0xa7, 0x40, 0x3d, 0x4d, 0x60, 0x6b, 0x6e,
+      0x07, 0x4e, 0xc5, 0xd3, 0xba, 0xf3, 0x9d, 0x18, 0x72, 0x60, 0x03, 0xca,
+      0x37, 0xa6, 0x2a, 0x74, 0xd1, 0xa2, 0xf5, 0x8e, 0x75, 0x06, 0x35, 0x8e,
+  };
+
+  for (size_t i = 0; i < sizeof(kInitMask); i++) {
+    seed_material[i] ^= kInitMask[i];
+  }
+
+  drbg->ctr = aes_ctr_set_key(&drbg->ks, NULL, &drbg->block, seed_material, 32);
+  OPENSSL_memcpy(drbg->counter.bytes, seed_material + 32, 16);
+  drbg->reseed_counter = 1;
+
+  return 1;
+}
+
+OPENSSL_COMPILE_ASSERT(CTR_DRBG_ENTROPY_LEN % AES_BLOCK_SIZE == 0,
+                       not_a_multiple_of_block_size);
+
+/* ctr_inc adds |n| to the last four bytes of |drbg->counter|, treated as a
+ * big-endian number. */
+static void ctr32_add(CTR_DRBG_STATE *drbg, uint32_t n) {
+  drbg->counter.words[3] =
+      CRYPTO_bswap4(CRYPTO_bswap4(drbg->counter.words[3]) + n);
+}
+
+static int CTR_DRBG_update(CTR_DRBG_STATE *drbg, const uint8_t *data,
+                           size_t data_len) {
+  /* Section 10.2.1.2. A value of |data_len| which less than
+   * |CTR_DRBG_ENTROPY_LEN| is permitted and acts the same as right-padding
+   * with zeros. This can save a copy. */
+  if (data_len > CTR_DRBG_ENTROPY_LEN) {
+    return 0;
+  }
+
+  uint8_t temp[CTR_DRBG_ENTROPY_LEN];
+  for (size_t i = 0; i < CTR_DRBG_ENTROPY_LEN; i += AES_BLOCK_SIZE) {
+    ctr32_add(drbg, 1);
+    drbg->block(drbg->counter.bytes, temp + i, &drbg->ks);
+  }
+
+  for (size_t i = 0; i < data_len; i++) {
+    temp[i] ^= data[i];
+  }
+
+  drbg->ctr = aes_ctr_set_key(&drbg->ks, NULL, &drbg->block, temp, 32);
+  OPENSSL_memcpy(drbg->counter.bytes, temp + 32, 16);
+
+  return 1;
+}
+
+int CTR_DRBG_reseed(CTR_DRBG_STATE *drbg,
+                    const uint8_t entropy[CTR_DRBG_ENTROPY_LEN],
+                    const uint8_t *additional_data,
+                    size_t additional_data_len) {
+  /* Section 10.2.1.4 */
+  uint8_t entropy_copy[CTR_DRBG_ENTROPY_LEN];
+
+  if (additional_data_len > 0) {
+    if (additional_data_len > CTR_DRBG_ENTROPY_LEN) {
+      return 0;
+    }
+
+    OPENSSL_memcpy(entropy_copy, entropy, CTR_DRBG_ENTROPY_LEN);
+    for (size_t i = 0; i < additional_data_len; i++) {
+      entropy_copy[i] ^= additional_data[i];
+    }
+
+    entropy = entropy_copy;
+  }
+
+  if (!CTR_DRBG_update(drbg, entropy, CTR_DRBG_ENTROPY_LEN)) {
+    return 0;
+  }
+
+  drbg->reseed_counter = 1;
+
+  return 1;
+}
+
+int CTR_DRBG_generate(CTR_DRBG_STATE *drbg, uint8_t *out, size_t out_len,
+                      const uint8_t *additional_data,
+                      size_t additional_data_len) {
+  /* See 9.3.1 */
+  if (out_len > CTR_DRBG_MAX_GENERATE_LENGTH) {
+    return 0;
+  }
+
+  /* See 10.2.1.5.1 */
+  if (drbg->reseed_counter > kMaxReseedCount) {
+    return 0;
+  }
+
+  if (additional_data_len != 0 &&
+      !CTR_DRBG_update(drbg, additional_data, additional_data_len)) {
+    return 0;
+  }
+
+  /* kChunkSize is used to interact better with the cache. Since the AES-CTR
+   * code assumes that it's encrypting rather than just writing keystream, the
+   * buffer has to be zeroed first. Without chunking, large reads would zero
+   * the whole buffer, flushing the L1 cache, and then do another pass (missing
+   * the cache every time) to “encrypt” it. The code can avoid this by
+   * chunking. */
+  static const size_t kChunkSize = 8 * 1024;
+
+  while (out_len >= AES_BLOCK_SIZE) {
+    size_t todo = kChunkSize;
+    if (todo > out_len) {
+      todo = out_len;
+    }
+
+    todo &= ~(AES_BLOCK_SIZE-1);
+    const size_t num_blocks = todo / AES_BLOCK_SIZE;
+
+    if (drbg->ctr) {
+      OPENSSL_memset(out, 0, todo);
+      ctr32_add(drbg, 1);
+      drbg->ctr(out, out, num_blocks, &drbg->ks, drbg->counter.bytes);
+      ctr32_add(drbg, num_blocks - 1);
+    } else {
+      for (size_t i = 0; i < todo; i += AES_BLOCK_SIZE) {
+        ctr32_add(drbg, 1);
+        drbg->block(drbg->counter.bytes, out + i, &drbg->ks);
+      }
+    }
+
+    out += todo;
+    out_len -= todo;
+  }
+
+  if (out_len > 0) {
+    uint8_t block[AES_BLOCK_SIZE];
+    ctr32_add(drbg, 1);
+    drbg->block(drbg->counter.bytes, block, &drbg->ks);
+
+    OPENSSL_memcpy(out, block, out_len);
+  }
+
+  if (!CTR_DRBG_update(drbg, additional_data, additional_data_len)) {
+    return 0;
+  }
+
+  drbg->reseed_counter++;
+  return 1;
+}
+
+void CTR_DRBG_clear(CTR_DRBG_STATE *drbg) {
+  OPENSSL_cleanse(drbg, sizeof(CTR_DRBG_STATE));
+}

crypto/rand/ctrdrbg_test.cc

@@ -0,0 +1,83 @@
+/* Copyright (c) 2017, Google Inc.
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
+ * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
+ * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+ * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
+
+#include <gtest/gtest.h>
+
+#include <openssl/rand.h>
+#include <openssl/sha.h>
+
+#include "internal.h"
+#include "../test/test_util.h"
+
+
+TEST(CTRDRBGTest, Basic) {
+  const uint8_t kSeed[CTR_DRBG_ENTROPY_LEN] = {
+      0xe4, 0xbc, 0x23, 0xc5, 0x08, 0x9a, 0x19, 0xd8, 0x6f, 0x41, 0x19, 0xcb,
+      0x3f, 0xa0, 0x8c, 0x0a, 0x49, 0x91, 0xe0, 0xa1, 0xde, 0xf1, 0x7e, 0x10,
+      0x1e, 0x4c, 0x14, 0xd9, 0xc3, 0x23, 0x46, 0x0a, 0x7c, 0x2f, 0xb5, 0x8e,
+      0x0b, 0x08, 0x6c, 0x6c, 0x57, 0xb5, 0x5f, 0x56, 0xca, 0xe2, 0x5b, 0xad,
+  };
+
+  CTR_DRBG_STATE drbg;
+  ASSERT_TRUE(CTR_DRBG_init(&drbg, kSeed, nullptr, 0));
+
+  const uint8_t kReseed[CTR_DRBG_ENTROPY_LEN] = {
+      0xfd, 0x85, 0xa8, 0x36, 0xbb, 0xa8, 0x50, 0x19, 0x88, 0x1e, 0x8c, 0x6b,
+      0xad, 0x23, 0xc9, 0x06, 0x1a, 0xdc, 0x75, 0x47, 0x76, 0x59, 0xac, 0xae,
+      0xa8, 0xe4, 0xa0, 0x1d, 0xfe, 0x07, 0xa1, 0x83, 0x2d, 0xad, 0x1c, 0x13,
+      0x6f, 0x59, 0xd7, 0x0f, 0x86, 0x53, 0xa5, 0xdc, 0x11, 0x86, 0x63, 0xd6,
+  };
+
+  ASSERT_TRUE(CTR_DRBG_reseed(&drbg, kReseed, nullptr, 0));
+
+  uint8_t out[64];
+  ASSERT_TRUE(CTR_DRBG_generate(&drbg, out, sizeof(out), nullptr, 0));
+  ASSERT_TRUE(CTR_DRBG_generate(&drbg, out, sizeof(out), nullptr, 0));
+
+  const uint8_t kExpected[64] = {
+      0xb2, 0xcb, 0x89, 0x05, 0xc0, 0x5e, 0x59, 0x50, 0xca, 0x31, 0x89,
+      0x50, 0x96, 0xbe, 0x29, 0xea, 0x3d, 0x5a, 0x3b, 0x82, 0xb2, 0x69,
+      0x49, 0x55, 0x54, 0xeb, 0x80, 0xfe, 0x07, 0xde, 0x43, 0xe1, 0x93,
+      0xb9, 0xe7, 0xc3, 0xec, 0xe7, 0x3b, 0x80, 0xe0, 0x62, 0xb1, 0xc1,
+      0xf6, 0x82, 0x02, 0xfb, 0xb1, 0xc5, 0x2a, 0x04, 0x0e, 0xa2, 0x47,
+      0x88, 0x64, 0x29, 0x52, 0x82, 0x23, 0x4a, 0xaa, 0xda,
+  };
+
+  EXPECT_EQ(Bytes(kExpected), Bytes(out));
+
+  CTR_DRBG_clear(&drbg);
+}
+
+TEST(CTRDRBGTest, Large) {
+  const uint8_t kSeed[CTR_DRBG_ENTROPY_LEN] = {0};
+
+  CTR_DRBG_STATE drbg;
+  ASSERT_TRUE(CTR_DRBG_init(&drbg, kSeed, nullptr, 0));
+
+  std::unique_ptr<uint8_t[]> buf(new uint8_t[CTR_DRBG_MAX_GENERATE_LENGTH]);
+  ASSERT_TRUE(CTR_DRBG_generate(&drbg, buf.get(), CTR_DRBG_MAX_GENERATE_LENGTH,
+                                nullptr, 0));
+
+  uint8_t digest[SHA256_DIGEST_LENGTH];
+  SHA256(buf.get(), CTR_DRBG_MAX_GENERATE_LENGTH, digest);
+
+  const uint8_t kExpected[SHA256_DIGEST_LENGTH] = {
+      0x69, 0x78, 0x15, 0x96, 0xca, 0xc0, 0x3f, 0x6a, 0x6d, 0xed, 0x22,
+      0x1e, 0x26, 0xd0, 0x75, 0x49, 0xa0, 0x4b, 0x91, 0x58, 0x3c, 0xf4,
+      0xe3, 0x6d, 0xff, 0x41, 0xbf, 0xb9, 0xf8, 0xa8, 0x1c, 0x2b,
+  };
+  EXPECT_EQ(Bytes(kExpected), Bytes(digest));
+
+  CTR_DRBG_clear(&drbg);
+}

crypto/rand/ctrdrbg_vector_test.cc

@@ -0,0 +1,73 @@
+/* Copyright (c) 2017, Google Inc.
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
+ * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
+ * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+ * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
+
+#include <openssl/rand.h>
+
+#include <openssl/crypto.h>
+
+#include "internal.h"
+#include "../test/test_util.h"
+#include "../test/file_test.h"
+
+
+static bool TestCTRDRBG(FileTest *t, void *arg) {
+  std::vector<uint8_t> seed, personalisation, reseed, ai_reseed, ai1, ai2,
+    expected;
+  if (!t->GetBytes(&seed, "EntropyInput") ||
+      !t->GetBytes(&personalisation, "PersonalizationString") ||
+      !t->GetBytes(&reseed, "EntropyInputReseed") ||
+      !t->GetBytes(&ai_reseed, "AdditionalInputReseed") ||
+      !t->GetBytes(&ai1, "AdditionalInput1") ||
+      !t->GetBytes(&ai2, "AdditionalInput2") ||
+      !t->GetBytes(&expected, "ReturnedBits")) {
+    t->PrintLine("missing value");
+    return false;
+  }
+
+  if (seed.size() != CTR_DRBG_ENTROPY_LEN ||
+      reseed.size() != CTR_DRBG_ENTROPY_LEN) {
+    t->PrintLine("bad seed length");
+    return false;
+  }
+
+  CTR_DRBG_STATE drbg;
+  CTR_DRBG_init(&drbg, seed.data(),
+                personalisation.size() > 0 ? personalisation.data() : nullptr,
+                personalisation.size());
+  CTR_DRBG_reseed(&drbg, reseed.data(),
+                  ai_reseed.size() > 0 ? ai_reseed.data() : nullptr,
+                  ai_reseed.size());
+
+  std::vector<uint8_t> out;
+  out.resize(expected.size());
+
+  CTR_DRBG_generate(&drbg, out.data(), out.size(),
+                    ai1.size() > 0 ? ai1.data() : nullptr, ai1.size());
+  CTR_DRBG_generate(&drbg, out.data(), out.size(),
+                    ai2.size() > 0 ? ai2.data() : nullptr, ai2.size());
+
+  return t->ExpectBytesEqual(expected.data(), expected.size(), out.data(),
+                             out.size());
+}
+
+int main(int argc, char **argv) {
+  CRYPTO_library_init();
+
+  if (argc != 2) {
+    fprintf(stderr, "%s <test file>\n", argv[0]);
+    return 1;
+  }
+
+  return FileTestMain(TestCTRDRBG, nullptr, argv[1]);
+}

crypto/rand/internal.h

@@ -15,6 +15,11 @@
 #ifndef OPENSSL_HEADER_CRYPTO_RAND_INTERNAL_H
 #define OPENSSL_HEADER_CRYPTO_RAND_INTERNAL_H
 
+#include <openssl/aes.h>
+
+#include "../internal.h"
+#include "../modes/internal.h"
+
 #if defined(__cplusplus)
 extern "C" {
 #endif
@@ -24,6 +29,52 @@ extern "C" {
  * system. */
 void CRYPTO_sysrand(uint8_t *buf, size_t len);
 
+/* CTR_DRBG_STATE contains the state of a CTR_DRBG based on AES-256. See SP
+ * 800-90Ar1. */
+typedef struct {
+  alignas(16) AES_KEY ks;
+  block128_f block;
+  ctr128_f ctr;
+  union {
+    uint8_t bytes[16];
+    uint32_t words[4];
+  } counter;
+  uint64_t reseed_counter;
+} CTR_DRBG_STATE;
+
+/* See SP 800-90Ar1, table 3. */
+#define CTR_DRBG_ENTROPY_LEN 48
+#define CTR_DRBG_MAX_GENERATE_LENGTH 65536
+
+/* CTR_DRBG_init initialises |*drbg| given |CTR_DRBG_ENTROPY_LEN| bytes of
+ * entropy in |entropy| and, optionally, a personalization string up to
+ * |CTR_DRBG_ENTROPY_LEN| bytes in length. It returns one on success and zero
+ * on error. */
+OPENSSL_EXPORT int CTR_DRBG_init(CTR_DRBG_STATE *drbg,
+                                 const uint8_t entropy[CTR_DRBG_ENTROPY_LEN],
+                                 const uint8_t *personalization,
+                                 size_t personalization_len);
+
+/* CTR_DRBG_reseed reseeds |drbg| given |CTR_DRBG_ENTROPY_LEN| bytes of entropy
+ * in |entropy| and, optionally, up to |CTR_DRBG_ENTROPY_LEN| bytes of
+ * additional data. It returns one on success or zero on error. */
+OPENSSL_EXPORT int CTR_DRBG_reseed(CTR_DRBG_STATE *drbg,
+                                   const uint8_t entropy[CTR_DRBG_ENTROPY_LEN],
+                                   const uint8_t *additional_data,
+                                   size_t additional_data_len);
+
+/* CTR_DRBG_generate processes to up |CTR_DRBG_ENTROPY_LEN| bytes of additional
+ * data (if any) and then writes |out_len| random bytes to |out|, where
+ * |out_len| <= |CTR_DRBG_MAX_GENERATE_LENGTH|. It returns one on success or
+ * zero on error. */
+OPENSSL_EXPORT int CTR_DRBG_generate(CTR_DRBG_STATE *drbg, uint8_t *out,
+                                     size_t out_len,
+                                     const uint8_t *additional_data,
+                                     size_t additional_data_len);
+
+/* CTR_DRBG_clear zeroises the state of |drbg|. */
+OPENSSL_EXPORT void CTR_DRBG_clear(CTR_DRBG_STATE *drbg);
+
 
 #if defined(__cplusplus)
 }  /* extern C */

include/openssl/base.h

@@ -227,7 +227,6 @@ typedef struct asn1_string_st ASN1_UTCTIME;
 typedef struct asn1_string_st ASN1_UTF8STRING;
 typedef struct asn1_string_st ASN1_VISIBLESTRING;
 typedef struct asn1_type_st ASN1_TYPE;
-
 typedef struct AUTHORITY_KEYID_st AUTHORITY_KEYID;
 typedef struct BASIC_CONSTRAINTS_st BASIC_CONSTRAINTS;
 typedef struct DIST_POINT_st DIST_POINT;

util/all_tests.json

@@ -69,6 +69,7 @@
 	["crypto/pkcs8/pkcs8_test"],
 	["crypto/poly1305/poly1305_test", "crypto/poly1305/poly1305_tests.txt"],
 	["crypto/pool/pool_test"],
+	["crypto/rand/ctrdrbg_vector_test", "crypto/rand/ctrdrbg_vectors.txt"],
 	["crypto/refcount_test"],
 	["crypto/thread_test"],
 	["crypto/x509/pkcs7_test"],