external/boringssl: Sync to faa539f877432814d0f2de19846eb99f2ea1e207.

This includes the following changes:

https://boringssl.googlesource.com/boringssl/+log/bbfe603519bc54fbc4c8dd87efe1ed385df550b4..faa539f877432814d0f2de19846eb99f2ea1e207

Test: BoringSSL CTS Presubmits
Change-Id: I3ea66c6a16d30b31f9a51e8154fa581a7d386918
diff --git a/src/crypto/cipher/tls_cbc.c b/src/crypto/cipher/tls_cbc.c
index 52880b0..a825c1c 100644
--- a/src/crypto/cipher/tls_cbc.c
+++ b/src/crypto/cipher/tls_cbc.c
@@ -73,20 +73,19 @@
  * supported by TLS.) */
 #define MAX_HASH_BLOCK_SIZE 128
 
-int EVP_tls_cbc_remove_padding(unsigned *out_padding_ok, unsigned *out_len,
-                               const uint8_t *in, unsigned in_len,
-                               unsigned block_size, unsigned mac_size) {
-  unsigned padding_length, good, to_check, i;
-  const unsigned overhead = 1 /* padding length byte */ + mac_size;
+int EVP_tls_cbc_remove_padding(size_t *out_padding_ok, size_t *out_len,
+                               const uint8_t *in, size_t in_len,
+                               size_t block_size, size_t mac_size) {
+  const size_t overhead = 1 /* padding length byte */ + mac_size;
 
   /* These lengths are all public so we can test them in non-constant time. */
   if (overhead > in_len) {
     return 0;
   }
 
-  padding_length = in[in_len - 1];
+  size_t padding_length = in[in_len - 1];
 
-  good = constant_time_ge(in_len, overhead + padding_length);
+  size_t good = constant_time_ge_s(in_len, overhead + padding_length);
   /* The padding consists of a length byte at the end of the record and
    * then that many bytes of padding, all with the same value as the
    * length byte. Thus, with the length byte included, there are i+1
@@ -96,12 +95,12 @@
    * decrypted information. Therefore we always have to check the maximum
    * amount of padding possible. (Again, the length of the record is
    * public information so we can use it.) */
-  to_check = 256; /* maximum amount of padding, inc length byte. */
+  size_t to_check = 256; /* maximum amount of padding, inc length byte. */
   if (to_check > in_len) {
     to_check = in_len;
   }
 
-  for (i = 0; i < to_check; i++) {
+  for (size_t i = 0; i < to_check; i++) {
     uint8_t mask = constant_time_ge_8(padding_length, i);
     uint8_t b = in[in_len - 1 - i];
     /* The final |padding_length+1| bytes should all have the value
@@ -111,7 +110,7 @@
 
   /* If any of the final |padding_length+1| bytes had the wrong value,
    * one or more of the lower eight bits of |good| will be cleared. */
-  good = constant_time_eq(0xff, good & 0xff);
+  good = constant_time_eq_s(0xff, good & 0xff);
 
   /* Always treat |padding_length| as zero on error. If, assuming block size of
    * 16, a padding of [<15 arbitrary bytes> 15] treated |padding_length| as 16
@@ -123,16 +122,15 @@
   return 1;
 }
 
-void EVP_tls_cbc_copy_mac(uint8_t *out, unsigned md_size,
-                          const uint8_t *in, unsigned in_len,
-                          unsigned orig_len) {
+void EVP_tls_cbc_copy_mac(uint8_t *out, size_t md_size, const uint8_t *in,
+                          size_t in_len, size_t orig_len) {
   uint8_t rotated_mac1[EVP_MAX_MD_SIZE], rotated_mac2[EVP_MAX_MD_SIZE];
   uint8_t *rotated_mac = rotated_mac1;
   uint8_t *rotated_mac_tmp = rotated_mac2;
 
   /* mac_end is the index of |in| just after the end of the MAC. */
-  unsigned mac_end = in_len;
-  unsigned mac_start = mac_end - md_size;
+  size_t mac_end = in_len;
+  size_t mac_start = mac_end - md_size;
 
   assert(orig_len >= in_len);
   assert(in_len >= md_size);
@@ -140,20 +138,20 @@
 
   /* scan_start contains the number of bytes that we can ignore because
    * the MAC's position can only vary by 255 bytes. */
-  unsigned scan_start = 0;
+  size_t scan_start = 0;
   /* This information is public so it's safe to branch based on it. */
   if (orig_len > md_size + 255 + 1) {
     scan_start = orig_len - (md_size + 255 + 1);
   }
 
-  unsigned rotate_offset = 0;
+  size_t rotate_offset = 0;
   uint8_t mac_started = 0;
   OPENSSL_memset(rotated_mac, 0, md_size);
-  for (unsigned i = scan_start, j = 0; i < orig_len; i++, j++) {
+  for (size_t i = scan_start, j = 0; i < orig_len; i++, j++) {
     if (j >= md_size) {
       j -= md_size;
     }
-    unsigned is_mac_start = constant_time_eq(i, mac_start);
+    size_t is_mac_start = constant_time_eq_s(i, mac_start);
     mac_started |= is_mac_start;
     uint8_t mac_ended = constant_time_ge_8(i, mac_end);
     rotated_mac[j] |= in[i] & mac_started & ~mac_ended;
@@ -163,12 +161,11 @@
 
   /* Now rotate the MAC. We rotate in log(md_size) steps, one for each bit
    * position. */
-  for (unsigned offset = 1; offset < md_size;
-       offset <<= 1, rotate_offset >>= 1) {
+  for (size_t offset = 1; offset < md_size; offset <<= 1, rotate_offset >>= 1) {
     /* Rotate by |offset| iff the corresponding bit is set in
      * |rotate_offset|, placing the result in |rotated_mac_tmp|. */
     const uint8_t skip_rotate = (rotate_offset & 1) - 1;
-    for (unsigned i = 0, j = offset; i < md_size; i++, j++) {
+    for (size_t i = 0, j = offset; i < md_size; i++, j++) {
       if (j >= md_size) {
         j -= md_size;
       }
@@ -211,40 +208,49 @@
     *((p)++) = (uint8_t)((n));       \
   } while (0)
 
+typedef union {
+  SHA_CTX sha1;
+  SHA256_CTX sha256;
+  SHA512_CTX sha512;
+} HASH_CTX;
+
+static void tls1_sha1_transform(HASH_CTX *ctx, const uint8_t *block) {
+  SHA1_Transform(&ctx->sha1, block);
+}
+
+static void tls1_sha256_transform(HASH_CTX *ctx, const uint8_t *block) {
+  SHA256_Transform(&ctx->sha256, block);
+}
+
+static void tls1_sha512_transform(HASH_CTX *ctx, const uint8_t *block) {
+  SHA512_Transform(&ctx->sha512, block);
+}
+
 /* These functions serialize the state of a hash and thus perform the standard
  * "final" operation without adding the padding and length that such a function
  * typically does. */
-static void tls1_sha1_final_raw(void *ctx, uint8_t *md_out) {
-  SHA_CTX *sha1 = ctx;
+static void tls1_sha1_final_raw(HASH_CTX *ctx, uint8_t *md_out) {
+  SHA_CTX *sha1 = &ctx->sha1;
   u32toBE(sha1->h[0], md_out);
   u32toBE(sha1->h[1], md_out);
   u32toBE(sha1->h[2], md_out);
   u32toBE(sha1->h[3], md_out);
   u32toBE(sha1->h[4], md_out);
 }
-#define LARGEST_DIGEST_CTX SHA_CTX
 
-static void tls1_sha256_final_raw(void *ctx, uint8_t *md_out) {
-  SHA256_CTX *sha256 = ctx;
-  unsigned i;
-
-  for (i = 0; i < 8; i++) {
+static void tls1_sha256_final_raw(HASH_CTX *ctx, uint8_t *md_out) {
+  SHA256_CTX *sha256 = &ctx->sha256;
+  for (unsigned i = 0; i < 8; i++) {
     u32toBE(sha256->h[i], md_out);
   }
 }
-#undef  LARGEST_DIGEST_CTX
-#define LARGEST_DIGEST_CTX SHA256_CTX
 
-static void tls1_sha512_final_raw(void *ctx, uint8_t *md_out) {
-  SHA512_CTX *sha512 = ctx;
-  unsigned i;
-
-  for (i = 0; i < 8; i++) {
+static void tls1_sha512_final_raw(HASH_CTX *ctx, uint8_t *md_out) {
+  SHA512_CTX *sha512 = &ctx->sha512;
+  for (unsigned i = 0; i < 8; i++) {
     u64toBE(sha512->h[i], md_out);
   }
 }
-#undef  LARGEST_DIGEST_CTX
-#define LARGEST_DIGEST_CTX SHA512_CTX
 
 int EVP_tls_cbc_record_digest_supported(const EVP_MD *md) {
   switch (EVP_MD_type(md)) {
@@ -264,54 +270,42 @@
                               size_t data_plus_mac_plus_padding_size,
                               const uint8_t *mac_secret,
                               unsigned mac_secret_length) {
-  union {
-    double align;
-    uint8_t c[sizeof(LARGEST_DIGEST_CTX)];
-  } md_state;
-  void (*md_final_raw)(void *ctx, uint8_t *md_out);
-  void (*md_transform)(void *ctx, const uint8_t *block);
+  HASH_CTX md_state;
+  void (*md_final_raw)(HASH_CTX *ctx, uint8_t *md_out);
+  void (*md_transform)(HASH_CTX *ctx, const uint8_t *block);
   unsigned md_size, md_block_size = 64;
-  unsigned len, max_mac_bytes, num_blocks, num_starting_blocks, k,
-           mac_end_offset, c, index_a, index_b;
-  unsigned int bits; /* at most 18 bits */
-  uint8_t length_bytes[MAX_HASH_BIT_COUNT_BYTES];
-  /* hmac_pad is the masked HMAC key. */
-  uint8_t hmac_pad[MAX_HASH_BLOCK_SIZE];
-  uint8_t first_block[MAX_HASH_BLOCK_SIZE];
-  uint8_t mac_out[EVP_MAX_MD_SIZE];
-  unsigned i, j, md_out_size_u;
-  EVP_MD_CTX md_ctx;
-  /* mdLengthSize is the number of bytes in the length field that terminates
-  * the hash. */
+  /* md_length_size is the number of bytes in the length field that terminates
+   * the hash. */
   unsigned md_length_size = 8;
 
-  /* This is a, hopefully redundant, check that allows us to forget about
-   * many possible overflows later in this function. */
-  assert(data_plus_mac_plus_padding_size < 1024 * 1024);
+  /* Bound the acceptable input so we can forget about many possible overflows
+   * later in this function. This is redundant with the record size limits in
+   * TLS. */
+  if (data_plus_mac_plus_padding_size >= 1024 * 1024) {
+    assert(0);
+    return 0;
+  }
 
   switch (EVP_MD_type(md)) {
     case NID_sha1:
-      SHA1_Init((SHA_CTX *)md_state.c);
+      SHA1_Init(&md_state.sha1);
       md_final_raw = tls1_sha1_final_raw;
-      md_transform =
-          (void (*)(void *ctx, const uint8_t *block))SHA1_Transform;
-      md_size = 20;
+      md_transform = tls1_sha1_transform;
+      md_size = SHA_DIGEST_LENGTH;
       break;
 
     case NID_sha256:
-      SHA256_Init((SHA256_CTX *)md_state.c);
+      SHA256_Init(&md_state.sha256);
       md_final_raw = tls1_sha256_final_raw;
-      md_transform =
-          (void (*)(void *ctx, const uint8_t *block))SHA256_Transform;
-      md_size = 32;
+      md_transform = tls1_sha256_transform;
+      md_size = SHA256_DIGEST_LENGTH;
       break;
 
     case NID_sha384:
-      SHA384_Init((SHA512_CTX *)md_state.c);
+      SHA384_Init(&md_state.sha512);
       md_final_raw = tls1_sha512_final_raw;
-      md_transform =
-          (void (*)(void *ctx, const uint8_t *block))SHA512_Transform;
-      md_size = 384 / 8;
+      md_transform = tls1_sha512_transform;
+      md_size = SHA384_DIGEST_LENGTH;
       md_block_size = 128;
       md_length_size = 16;
       break;
@@ -328,7 +322,7 @@
   assert(md_block_size <= MAX_HASH_BLOCK_SIZE);
   assert(md_size <= EVP_MAX_MD_SIZE);
 
-  static const unsigned kHeaderLength = 13;
+  static const size_t kHeaderLength = 13;
 
   /* kVarianceBlocks is the number of blocks of the hash that we have to
    * calculate in constant time because they could be altered by the
@@ -337,16 +331,16 @@
    * TLSv1 has MACs up to 48 bytes long (SHA-384) and the padding is not
    * required to be minimal. Therefore we say that the final six blocks
    * can vary based on the padding. */
-  static const unsigned kVarianceBlocks = 6;
+  static const size_t kVarianceBlocks = 6;
 
   /* From now on we're dealing with the MAC, which conceptually has 13
    * bytes of `header' before the start of the data. */
-  len = data_plus_mac_plus_padding_size + kHeaderLength;
+  size_t len = data_plus_mac_plus_padding_size + kHeaderLength;
   /* max_mac_bytes contains the maximum bytes of bytes in the MAC, including
-  * |header|, assuming that there's no padding. */
-  max_mac_bytes = len - md_size - 1;
+   * |header|, assuming that there's no padding. */
+  size_t max_mac_bytes = len - md_size - 1;
   /* num_blocks is the maximum number of hash blocks. */
-  num_blocks =
+  size_t num_blocks =
       (max_mac_bytes + 1 + md_length_size + md_block_size - 1) / md_block_size;
   /* In order to calculate the MAC in constant time we have to handle
    * the final blocks specially because the padding value could cause the
@@ -354,43 +348,47 @@
    * can't leak where. However, |num_starting_blocks| worth of data can
    * be hashed right away because no padding value can affect whether
    * they are plaintext. */
-  num_starting_blocks = 0;
+  size_t num_starting_blocks = 0;
   /* k is the starting byte offset into the conceptual header||data where
    * we start processing. */
-  k = 0;
+  size_t k = 0;
   /* mac_end_offset is the index just past the end of the data to be
    * MACed. */
-  mac_end_offset = data_plus_mac_size + kHeaderLength - md_size;
+  size_t mac_end_offset = data_plus_mac_size + kHeaderLength - md_size;
   /* c is the index of the 0x80 byte in the final hash block that
    * contains application data. */
-  c = mac_end_offset % md_block_size;
+  size_t c = mac_end_offset % md_block_size;
   /* index_a is the hash block number that contains the 0x80 terminating
    * value. */
-  index_a = mac_end_offset / md_block_size;
+  size_t index_a = mac_end_offset / md_block_size;
   /* index_b is the hash block number that contains the 64-bit hash
    * length, in bits. */
-  index_b = (mac_end_offset + md_length_size) / md_block_size;
-  /* bits is the hash-length in bits. It includes the additional hash
-   * block for the masked HMAC key. */
+  size_t index_b = (mac_end_offset + md_length_size) / md_block_size;
 
   if (num_blocks > kVarianceBlocks) {
     num_starting_blocks = num_blocks - kVarianceBlocks;
     k = md_block_size * num_starting_blocks;
   }
 
-  bits = 8 * mac_end_offset;
+  /* bits is the hash-length in bits. It includes the additional hash
+   * block for the masked HMAC key. */
+  size_t bits = 8 * mac_end_offset; /* at most 18 bits to represent */
 
   /* Compute the initial HMAC block. */
   bits += 8 * md_block_size;
+  /* hmac_pad is the masked HMAC key. */
+  uint8_t hmac_pad[MAX_HASH_BLOCK_SIZE];
   OPENSSL_memset(hmac_pad, 0, md_block_size);
   assert(mac_secret_length <= sizeof(hmac_pad));
   OPENSSL_memcpy(hmac_pad, mac_secret, mac_secret_length);
-  for (i = 0; i < md_block_size; i++) {
+  for (size_t i = 0; i < md_block_size; i++) {
     hmac_pad[i] ^= 0x36;
   }
 
-  md_transform(md_state.c, hmac_pad);
+  md_transform(&md_state, hmac_pad);
 
+  /* The length check means |bits| fits in four bytes. */
+  uint8_t length_bytes[MAX_HASH_BIT_COUNT_BYTES];
   OPENSSL_memset(length_bytes, 0, md_length_size - 4);
   length_bytes[md_length_size - 4] = (uint8_t)(bits >> 24);
   length_bytes[md_length_size - 3] = (uint8_t)(bits >> 16);
@@ -399,27 +397,29 @@
 
   if (k > 0) {
     /* k is a multiple of md_block_size. */
+    uint8_t first_block[MAX_HASH_BLOCK_SIZE];
     OPENSSL_memcpy(first_block, header, 13);
     OPENSSL_memcpy(first_block + 13, data, md_block_size - 13);
-    md_transform(md_state.c, first_block);
-    for (i = 1; i < k / md_block_size; i++) {
-      md_transform(md_state.c, data + md_block_size * i - 13);
+    md_transform(&md_state, first_block);
+    for (size_t i = 1; i < k / md_block_size; i++) {
+      md_transform(&md_state, data + md_block_size * i - 13);
     }
   }
 
+  uint8_t mac_out[EVP_MAX_MD_SIZE];
   OPENSSL_memset(mac_out, 0, sizeof(mac_out));
 
   /* We now process the final hash blocks. For each block, we construct
    * it in constant time. If the |i==index_a| then we'll include the 0x80
    * bytes and zero pad etc. For each block we selectively copy it, in
    * constant time, to |mac_out|. */
-  for (i = num_starting_blocks; i <= num_starting_blocks + kVarianceBlocks;
-       i++) {
+  for (size_t i = num_starting_blocks;
+       i <= num_starting_blocks + kVarianceBlocks; i++) {
     uint8_t block[MAX_HASH_BLOCK_SIZE];
     uint8_t is_block_a = constant_time_eq_8(i, index_a);
     uint8_t is_block_b = constant_time_eq_8(i, index_b);
-    for (j = 0; j < md_block_size; j++) {
-      uint8_t b = 0, is_past_c, is_past_cp1;
+    for (size_t j = 0; j < md_block_size; j++) {
+      uint8_t b = 0;
       if (k < kHeaderLength) {
         b = header[k];
       } else if (k < data_plus_mac_plus_padding_size + kHeaderLength) {
@@ -427,8 +427,8 @@
       }
       k++;
 
-      is_past_c = is_block_a & constant_time_ge_8(j, c);
-      is_past_cp1 = is_block_a & constant_time_ge_8(j, c + 1);
+      uint8_t is_past_c = is_block_a & constant_time_ge_8(j, c);
+      uint8_t is_past_cp1 = is_block_a & constant_time_ge_8(j, c + 1);
       /* If this is the block containing the end of the
        * application data, and we are at the offset for the
        * 0x80 value, then overwrite b with 0x80. */
@@ -453,14 +453,15 @@
       block[j] = b;
     }
 
-    md_transform(md_state.c, block);
-    md_final_raw(md_state.c, block);
+    md_transform(&md_state, block);
+    md_final_raw(&md_state, block);
     /* If this is index_b, copy the hash value to |mac_out|. */
-    for (j = 0; j < md_size; j++) {
+    for (size_t j = 0; j < md_size; j++) {
       mac_out[j] |= block[j] & is_block_b;
     }
   }
 
+  EVP_MD_CTX md_ctx;
   EVP_MD_CTX_init(&md_ctx);
   if (!EVP_DigestInit_ex(&md_ctx, md, NULL /* engine */)) {
     EVP_MD_CTX_cleanup(&md_ctx);
@@ -468,12 +469,13 @@
   }
 
   /* Complete the HMAC in the standard manner. */
-  for (i = 0; i < md_block_size; i++) {
+  for (size_t i = 0; i < md_block_size; i++) {
     hmac_pad[i] ^= 0x6a;
   }
 
   EVP_DigestUpdate(&md_ctx, hmac_pad, md_block_size);
   EVP_DigestUpdate(&md_ctx, mac_out, md_size);
+  unsigned md_out_size_u;
   EVP_DigestFinal(&md_ctx, md_out, &md_out_size_u);
   *md_out_size = md_out_size_u;
   EVP_MD_CTX_cleanup(&md_ctx);