Import BoringSSL's crypto bytestring and crypto bytebuilder APIs.

This is imported with as few changes as possible for the initial commit.
I removed OPENSSL_EXPORT, replaced OPENSSL_malloc() etc with malloc()
and changed a few header includes.

BoringSSL has this as part of their public API.  We're leaving it internal
to libssl for now.

Based on BoringSSL's CBB/CBS API as of commit
c5cc15b4f5b1d6e9b9112cb8d30205a638aa2c54.

input + ok jsing@, miod@

1 files changed, 390 insertions, 0 deletions

diff --git a/lib/libssl/bs_cbs.c b/lib/libssl/bs_cbs.c
new file mode 100644
index 00000000000..7edfe652885
--- /dev/null
+++ b/lib/libssl/bs_cbs.c
@@ -0,0 +1,390 @@
+/*	$OpenBSD: bs_cbs.c,v 1.1 2015/02/06 09:36:16 doug Exp $	*/
+/*
+ * Copyright (c) 2014, 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 <assert.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <openssl/opensslconf.h>
+#include <openssl/buffer.h>
+#include <openssl/crypto.h>
+
+#include "bytestring.h"
+
+void CBS_init(CBS *cbs, const uint8_t *data, size_t len) {
+  cbs->data = data;
+  cbs->len = len;
+}
+
+static int cbs_get(CBS *cbs, const uint8_t **p, size_t n) {
+  if (cbs->len < n) {
+    return 0;
+  }
+
+  *p = cbs->data;
+  cbs->data += n;
+  cbs->len -= n;
+  return 1;
+}
+
+int CBS_skip(CBS *cbs, size_t len) {
+  const uint8_t *dummy;
+  return cbs_get(cbs, &dummy, len);
+}
+
+const uint8_t *CBS_data(const CBS *cbs) {
+  return cbs->data;
+}
+
+size_t CBS_len(const CBS *cbs) {
+  return cbs->len;
+}
+
+int CBS_stow(const CBS *cbs, uint8_t **out_ptr, size_t *out_len) {
+  if (*out_ptr != NULL) {
+    free(*out_ptr);
+    *out_ptr = NULL;
+  }
+  *out_len = 0;
+
+  if (cbs->len == 0) {
+    return 1;
+  }
+  *out_ptr = BUF_memdup(cbs->data, cbs->len);
+  if (*out_ptr == NULL) {
+    return 0;
+  }
+  *out_len = cbs->len;
+  return 1;
+}
+
+int CBS_strdup(const CBS *cbs, char **out_ptr) {
+  if (*out_ptr != NULL) {
+    free(*out_ptr);
+  }
+  *out_ptr = strndup((const char*)cbs->data, cbs->len);
+  return (*out_ptr != NULL);
+}
+
+int CBS_contains_zero_byte(const CBS *cbs) {
+  return memchr(cbs->data, 0, cbs->len) != NULL;
+}
+
+int CBS_mem_equal(const CBS *cbs, const uint8_t *data, size_t len) {
+  if (len != cbs->len)
+    return 0;
+  return CRYPTO_memcmp(cbs->data, data, len) == 0;
+}
+
+static int cbs_get_u(CBS *cbs, uint32_t *out, size_t len) {
+  uint32_t result = 0;
+  size_t i;
+  const uint8_t *data;
+
+  if (!cbs_get(cbs, &data, len)) {
+    return 0;
+  }
+  for (i = 0; i < len; i++) {
+    result <<= 8;
+    result |= data[i];
+  }
+  *out = result;
+  return 1;
+}
+
+int CBS_get_u8(CBS *cbs, uint8_t *out) {
+  const uint8_t *v;
+  if (!cbs_get(cbs, &v, 1)) {
+    return 0;
+  }
+  *out = *v;
+  return 1;
+}
+
+int CBS_get_u16(CBS *cbs, uint16_t *out) {
+  uint32_t v;
+  if (!cbs_get_u(cbs, &v, 2)) {
+    return 0;
+  }
+  *out = v;
+  return 1;
+}
+
+int CBS_get_u24(CBS *cbs, uint32_t *out) {
+  return cbs_get_u(cbs, out, 3);
+}
+
+int CBS_get_u32(CBS *cbs, uint32_t *out) {
+  return cbs_get_u(cbs, out, 4);
+}
+
+int CBS_get_bytes(CBS *cbs, CBS *out, size_t len) {
+  const uint8_t *v;
+  if (!cbs_get(cbs, &v, len)) {
+    return 0;
+  }
+  CBS_init(out, v, len);
+  return 1;
+}
+
+static int cbs_get_length_prefixed(CBS *cbs, CBS *out, size_t len_len) {
+  uint32_t len;
+  if (!cbs_get_u(cbs, &len, len_len)) {
+    return 0;
+  }
+  return CBS_get_bytes(cbs, out, len);
+}
+
+int CBS_get_u8_length_prefixed(CBS *cbs, CBS *out) {
+  return cbs_get_length_prefixed(cbs, out, 1);
+}
+
+int CBS_get_u16_length_prefixed(CBS *cbs, CBS *out) {
+  return cbs_get_length_prefixed(cbs, out, 2);
+}
+
+int CBS_get_u24_length_prefixed(CBS *cbs, CBS *out) {
+  return cbs_get_length_prefixed(cbs, out, 3);
+}
+
+int CBS_get_any_asn1_element(CBS *cbs, CBS *out, unsigned *out_tag,
+                             size_t *out_header_len) {
+  uint8_t tag, length_byte;
+  CBS header = *cbs;
+  CBS throwaway;
+
+  if (out == NULL) {
+    out = &throwaway;
+  }
+
+  if (!CBS_get_u8(&header, &tag) ||
+      !CBS_get_u8(&header, &length_byte)) {
+    return 0;
+  }
+
+  if ((tag & 0x1f) == 0x1f) {
+    /* Long form tags are not supported. */
+    return 0;
+  }
+
+  if (out_tag != NULL) {
+    *out_tag = tag;
+  }
+
+  size_t len;
+  if ((length_byte & 0x80) == 0) {
+    /* Short form length. */
+    len = ((size_t) length_byte) + 2;
+    if (out_header_len != NULL) {
+      *out_header_len = 2;
+    }
+  } else {
+    /* Long form length. */
+    const size_t num_bytes = length_byte & 0x7f;
+    uint32_t len32;
+
+    if ((tag & CBS_ASN1_CONSTRUCTED) != 0 && num_bytes == 0) {
+      /* indefinite length */
+      *out_header_len = 2;
+      return CBS_get_bytes(cbs, out, 2);
+    }
+
+    if (num_bytes == 0 || num_bytes > 4) {
+      return 0;
+    }
+    if (!cbs_get_u(&header, &len32, num_bytes)) {
+      return 0;
+    }
+    if (len32 < 128) {
+      /* Length should have used short-form encoding. */
+      return 0;
+    }
+    if ((len32 >> ((num_bytes-1)*8)) == 0) {
+      /* Length should have been at least one byte shorter. */
+      return 0;
+    }
+    len = len32;
+    if (len + 2 + num_bytes < len) {
+      /* Overflow. */
+      return 0;
+    }
+    len += 2 + num_bytes;
+    if (out_header_len != NULL) {
+      *out_header_len = 2 + num_bytes;
+    }
+  }
+
+  return CBS_get_bytes(cbs, out, len);
+}
+
+static int cbs_get_asn1(CBS *cbs, CBS *out, unsigned tag_value,
+                        int skip_header) {
+  size_t header_len;
+  unsigned tag;
+  CBS throwaway;
+
+  if (out == NULL) {
+    out = &throwaway;
+  }
+
+  if (!CBS_get_any_asn1_element(cbs, out, &tag, &header_len) ||
+      tag != tag_value ||
+      (header_len > 0 &&
+       /* This ensures that the tag is either zero length or
+        * indefinite-length. */
+       CBS_len(out) == header_len &&
+       CBS_data(out)[header_len - 1] == 0x80)) {
+    return 0;
+  }
+
+  if (skip_header && !CBS_skip(out, header_len)) {
+    assert(0);
+    return 0;
+  }
+
+  return 1;
+}
+
+int CBS_get_asn1(CBS *cbs, CBS *out, unsigned tag_value) {
+  return cbs_get_asn1(cbs, out, tag_value, 1 /* skip header */);
+}
+
+int CBS_get_asn1_element(CBS *cbs, CBS *out, unsigned tag_value) {
+  return cbs_get_asn1(cbs, out, tag_value, 0 /* include header */);
+}
+
+int CBS_peek_asn1_tag(const CBS *cbs, unsigned tag_value) {
+  if (CBS_len(cbs) < 1) {
+    return 0;
+  }
+  return CBS_data(cbs)[0] == tag_value;
+}
+
+int CBS_get_asn1_uint64(CBS *cbs, uint64_t *out) {
+  CBS bytes;
+  const uint8_t *data;
+  size_t i, len;
+
+  if (!CBS_get_asn1(cbs, &bytes, CBS_ASN1_INTEGER)) {
+    return 0;
+  }
+
+  *out = 0;
+  data = CBS_data(&bytes);
+  len = CBS_len(&bytes);
+
+  if (len == 0) {
+    /* An INTEGER is encoded with at least one octet. */
+    return 0;
+  }
+
+  if ((data[0] & 0x80) != 0) {
+    /* negative number */
+    return 0;
+  }
+
+  for (i = 0; i < len; i++) {
+    if ((*out >> 56) != 0) {
+      /* Too large to represent as a uint64_t. */
+      return 0;
+    }
+    *out <<= 8;
+    *out |= data[i];
+  }
+
+  return 1;
+}
+
+int CBS_get_optional_asn1(CBS *cbs, CBS *out, int *out_present, unsigned tag) {
+  if (CBS_peek_asn1_tag(cbs, tag)) {
+    if (!CBS_get_asn1(cbs, out, tag)) {
+      return 0;
+    }
+    *out_present = 1;
+  } else {
+    *out_present = 0;
+  }
+  return 1;
+}
+
+int CBS_get_optional_asn1_octet_string(CBS *cbs, CBS *out, int *out_present,
+                                       unsigned tag) {
+  CBS child;
+  int present;
+  if (!CBS_get_optional_asn1(cbs, &child, &present, tag)) {
+    return 0;
+  }
+  if (present) {
+    if (!CBS_get_asn1(&child, out, CBS_ASN1_OCTETSTRING) ||
+        CBS_len(&child) != 0) {
+      return 0;
+    }
+  } else {
+    CBS_init(out, NULL, 0);
+  }
+  if (out_present) {
+    *out_present = present;
+  }
+  return 1;
+}
+
+int CBS_get_optional_asn1_uint64(CBS *cbs, uint64_t *out, unsigned tag,
+                                 uint64_t default_value) {
+  CBS child;
+  int present;
+  if (!CBS_get_optional_asn1(cbs, &child, &present, tag)) {
+    return 0;
+  }
+  if (present) {
+    if (!CBS_get_asn1_uint64(&child, out) ||
+        CBS_len(&child) != 0) {
+      return 0;
+    }
+  } else {
+    *out = default_value;
+  }
+  return 1;
+}
+
+int CBS_get_optional_asn1_bool(CBS *cbs, int *out, unsigned tag,
+                               int default_value) {
+  CBS child, child2;
+  int present;
+  if (!CBS_get_optional_asn1(cbs, &child, &present, tag)) {
+    return 0;
+  }
+  if (present) {
+    uint8_t boolean;
+
+    if (!CBS_get_asn1(&child, &child2, CBS_ASN1_BOOLEAN) ||
+        CBS_len(&child2) != 1 ||
+        CBS_len(&child) != 0) {
+      return 0;
+    }
+
+    boolean = CBS_data(&child2)[0];
+    if (boolean == 0) {
+      *out = 0;
+    } else if (boolean == 0xff) {
+      *out = 1;
+    } else {
+      return 0;
+    }
+  } else {
+    *out = default_value;
+  }
+  return 1;
+}