third_party/boringssl/src/crypto/bytestring/ber.c - cobalt - Git at Google

 /* 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 <openssl/opensslconf.h>
 #if !defined(OPENSSL_SYS_STARBOARD)
 #include <assert.h>
 #include <string.h>
 #endif  // !defined(OPENSSL_SYS_STARBOARD)

 #include <openssl/mem.h>
 #include <openssl/bytestring.h>

 #include "internal.h"
 #include "../internal.h"


 // kMaxDepth is a just a sanity limit. The code should be such that the length
 // of the input being processes always decreases. None the less, a very large
 // input could otherwise cause the stack to overflow.
 static const unsigned kMaxDepth = 2048;

 // is_string_type returns one if |tag| is a string type and zero otherwise. It
 // ignores the constructed bit.
 static int is_string_type(unsigned tag) {
   switch (tag & ~CBS_ASN1_CONSTRUCTED) {
     case CBS_ASN1_BITSTRING:
     case CBS_ASN1_OCTETSTRING:
     case CBS_ASN1_UTF8STRING:
     case CBS_ASN1_NUMERICSTRING:
     case CBS_ASN1_PRINTABLESTRING:
     case CBS_ASN1_T61STRING:
     case CBS_ASN1_VIDEOTEXSTRING:
     case CBS_ASN1_IA5STRING:
     case CBS_ASN1_GRAPHICSTRING:
     case CBS_ASN1_VISIBLESTRING:
     case CBS_ASN1_GENERALSTRING:
     case CBS_ASN1_UNIVERSALSTRING:
     case CBS_ASN1_BMPSTRING:
       return 1;
     default:
       return 0;
   }
 }

 // cbs_find_ber walks an ASN.1 structure in |orig_in| and sets |*ber_found|
 // depending on whether an indefinite length element or constructed string was
 // found. The value of |orig_in| is not changed. It returns one on success (i.e.
 // |*ber_found| was set) and zero on error.
 static int cbs_find_ber(const CBS *orig_in, char *ber_found, unsigned depth) {
   CBS in;

   if (depth > kMaxDepth) {
     return 0;
   }

   CBS_init(&in, CBS_data(orig_in), CBS_len(orig_in));
   *ber_found = 0;

   while (CBS_len(&in) > 0) {
     CBS contents;
     unsigned tag;
     size_t header_len;

     if (!CBS_get_any_ber_asn1_element(&in, &contents, &tag, &header_len)) {
       return 0;
     }
     if (CBS_len(&contents) == header_len &&
         header_len > 0 &&
         CBS_data(&contents)[header_len-1] == 0x80) {
       // Found an indefinite-length element.
       *ber_found = 1;
       return 1;
     }
     if (tag & CBS_ASN1_CONSTRUCTED) {
       if (is_string_type(tag)) {
         // Constructed strings are only legal in BER and require conversion.
         *ber_found = 1;
         return 1;
       }
       if (!CBS_skip(&contents, header_len) ||
           !cbs_find_ber(&contents, ber_found, depth + 1)) {
         return 0;
       }
     }
   }

   return 1;
 }

 // is_eoc returns true if |header_len| and |contents|, as returned by
 // |CBS_get_any_ber_asn1_element|, indicate an "end of contents" (EOC) value.
 static char is_eoc(size_t header_len, CBS *contents) {
   return header_len == 2 && CBS_len(contents) == 2 &&
          OPENSSL_memcmp(CBS_data(contents), "\x00\x00", 2) == 0;
 }

 // cbs_convert_ber reads BER data from |in| and writes DER data to |out|. If
 // |string_tag| is non-zero, then all elements must match |string_tag| up to the
 // constructed bit and primitive element bodies are written to |out| without
 // element headers. This is used when concatenating the fragments of a
 // constructed string. If |looking_for_eoc| is set then any EOC elements found
 // will cause the function to return after consuming it. It returns one on
 // success and zero on error.
 static int cbs_convert_ber(CBS *in, CBB *out, unsigned string_tag,
                            char looking_for_eoc, unsigned depth) {
   assert(!(string_tag & CBS_ASN1_CONSTRUCTED));

   if (depth > kMaxDepth) {
     return 0;
   }

   while (CBS_len(in) > 0) {
     CBS contents;
     unsigned tag, child_string_tag = string_tag;
     size_t header_len;
     CBB *out_contents, out_contents_storage;

     if (!CBS_get_any_ber_asn1_element(in, &contents, &tag, &header_len)) {
       return 0;
     }

     if (is_eoc(header_len, &contents)) {
       return looking_for_eoc;
     }

     if (string_tag != 0) {
       // This is part of a constructed string. All elements must match
       // |string_tag| up to the constructed bit and get appended to |out|
       // without a child element.
       if ((tag & ~CBS_ASN1_CONSTRUCTED) != string_tag) {
         return 0;
       }
       out_contents = out;
     } else {
       unsigned out_tag = tag;
       if ((tag & CBS_ASN1_CONSTRUCTED) && is_string_type(tag)) {
         // If a constructed string, clear the constructed bit and inform
         // children to concatenate bodies.
         out_tag &= ~CBS_ASN1_CONSTRUCTED;
         child_string_tag = out_tag;
       }
       if (!CBB_add_asn1(out, &out_contents_storage, out_tag)) {
         return 0;
       }
       out_contents = &out_contents_storage;
     }

     if (CBS_len(&contents) == header_len && header_len > 0 &&
         CBS_data(&contents)[header_len - 1] == 0x80) {
       // This is an indefinite length element.
       if (!cbs_convert_ber(in, out_contents, child_string_tag,
                            1 /* looking for eoc */, depth + 1) ||
           !CBB_flush(out)) {
         return 0;
       }
       continue;
     }

     if (!CBS_skip(&contents, header_len)) {
       return 0;
     }

     if (tag & CBS_ASN1_CONSTRUCTED) {
       // Recurse into children.
       if (!cbs_convert_ber(&contents, out_contents, child_string_tag,
                            0 /* not looking for eoc */, depth + 1)) {
         return 0;
       }
     } else {
       // Copy primitive contents as-is.
       if (!CBB_add_bytes(out_contents, CBS_data(&contents),
                          CBS_len(&contents))) {
         return 0;
       }
     }

     if (!CBB_flush(out)) {
       return 0;
     }
   }

   return looking_for_eoc == 0;
 }

 int CBS_asn1_ber_to_der(CBS *in, CBS *out, uint8_t **out_storage) {
   CBB cbb;

   // First, do a quick walk to find any indefinite-length elements. Most of the
   // time we hope that there aren't any and thus we can quickly return.
   char conversion_needed;
   if (!cbs_find_ber(in, &conversion_needed, 0)) {
     return 0;
   }

   if (!conversion_needed) {
     if (!CBS_get_any_asn1_element(in, out, NULL, NULL)) {
       return 0;
     }
     *out_storage = NULL;
     return 1;
   }

   size_t len;
   if (!CBB_init(&cbb, CBS_len(in)) ||
       !cbs_convert_ber(in, &cbb, 0, 0, 0) ||
       !CBB_finish(&cbb, out_storage, &len)) {
     CBB_cleanup(&cbb);
     return 0;
   }

   CBS_init(out, *out_storage, len);
   return 1;
 }

 int CBS_get_asn1_implicit_string(CBS *in, CBS *out, uint8_t **out_storage,
                                  unsigned outer_tag, unsigned inner_tag) {
   assert(!(outer_tag & CBS_ASN1_CONSTRUCTED));
   assert(!(inner_tag & CBS_ASN1_CONSTRUCTED));
   assert(is_string_type(inner_tag));

   if (CBS_peek_asn1_tag(in, outer_tag)) {
     // Normal implicitly-tagged string.
     *out_storage = NULL;
     return CBS_get_asn1(in, out, outer_tag);
   }

   // Otherwise, try to parse an implicitly-tagged constructed string.
   // |CBS_asn1_ber_to_der| is assumed to have run, so only allow one level deep
   // of nesting.
   CBB result;
   CBS child;
   if (!CBB_init(&result, CBS_len(in)) ||
       !CBS_get_asn1(in, &child, outer_tag | CBS_ASN1_CONSTRUCTED)) {
     goto err;
   }

   while (CBS_len(&child) > 0) {
     CBS chunk;
     if (!CBS_get_asn1(&child, &chunk, inner_tag) ||
         !CBB_add_bytes(&result, CBS_data(&chunk), CBS_len(&chunk))) {
       goto err;
     }
   }

   uint8_t *data;
   size_t len;
   if (!CBB_finish(&result, &data, &len)) {
     goto err;
   }

   CBS_init(out, data, len);
   *out_storage = data;
   return 1;

 err:
   CBB_cleanup(&result);
   return 0;
 }
	/* 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 <openssl/opensslconf.h>
	#if !defined(OPENSSL_SYS_STARBOARD)
	#include <assert.h>
	#include <string.h>
	#endif // !defined(OPENSSL_SYS_STARBOARD)

	#include <openssl/mem.h>
	#include <openssl/bytestring.h>

	#include "internal.h"
	#include "../internal.h"


	// kMaxDepth is a just a sanity limit. The code should be such that the length
	// of the input being processes always decreases. None the less, a very large
	// input could otherwise cause the stack to overflow.
	static const unsigned kMaxDepth = 2048;

	// is_string_type returns one if \|tag\| is a string type and zero otherwise. It
	// ignores the constructed bit.
	static int is_string_type(unsigned tag) {
	switch (tag & ~CBS_ASN1_CONSTRUCTED) {
	case CBS_ASN1_BITSTRING:
	case CBS_ASN1_OCTETSTRING:
	case CBS_ASN1_UTF8STRING:
	case CBS_ASN1_NUMERICSTRING:
	case CBS_ASN1_PRINTABLESTRING:
	case CBS_ASN1_T61STRING:
	case CBS_ASN1_VIDEOTEXSTRING:
	case CBS_ASN1_IA5STRING:
	case CBS_ASN1_GRAPHICSTRING:
	case CBS_ASN1_VISIBLESTRING:
	case CBS_ASN1_GENERALSTRING:
	case CBS_ASN1_UNIVERSALSTRING:
	case CBS_ASN1_BMPSTRING:
	return 1;
	default:
	return 0;
	}
	}

	// cbs_find_ber walks an ASN.1 structure in \|orig_in\| and sets \|*ber_found\|
	// depending on whether an indefinite length element or constructed string was
	// found. The value of \|orig_in\| is not changed. It returns one on success (i.e.
	// \|*ber_found\| was set) and zero on error.
	static int cbs_find_ber(const CBS orig_in, char ber_found, unsigned depth) {
	CBS in;

	if (depth > kMaxDepth) {
	return 0;
	}

	CBS_init(&in, CBS_data(orig_in), CBS_len(orig_in));
	*ber_found = 0;

	while (CBS_len(&in) > 0) {
	CBS contents;
	unsigned tag;
	size_t header_len;

	if (!CBS_get_any_ber_asn1_element(&in, &contents, &tag, &header_len)) {
	return 0;
	}
	if (CBS_len(&contents) == header_len &&
	header_len > 0 &&
	CBS_data(&contents)[header_len-1] == 0x80) {
	// Found an indefinite-length element.
	*ber_found = 1;
	return 1;
	}
	if (tag & CBS_ASN1_CONSTRUCTED) {
	if (is_string_type(tag)) {
	// Constructed strings are only legal in BER and require conversion.
	*ber_found = 1;
	return 1;
	}
	if (!CBS_skip(&contents, header_len) \|\|
	!cbs_find_ber(&contents, ber_found, depth + 1)) {
	return 0;
	}
	}
	}

	return 1;
	}

	// is_eoc returns true if \|header_len\| and \|contents\|, as returned by
	// \|CBS_get_any_ber_asn1_element\|, indicate an "end of contents" (EOC) value.
	static char is_eoc(size_t header_len, CBS *contents) {
	return header_len == 2 && CBS_len(contents) == 2 &&
	OPENSSL_memcmp(CBS_data(contents), "\x00\x00", 2) == 0;
	}

	// cbs_convert_ber reads BER data from \|in\| and writes DER data to \|out\|. If
	// \|string_tag\| is non-zero, then all elements must match \|string_tag\| up to the
	// constructed bit and primitive element bodies are written to \|out\| without
	// element headers. This is used when concatenating the fragments of a
	// constructed string. If \|looking_for_eoc\| is set then any EOC elements found
	// will cause the function to return after consuming it. It returns one on
	// success and zero on error.
	static int cbs_convert_ber(CBS in, CBB out, unsigned string_tag,
	char looking_for_eoc, unsigned depth) {
	assert(!(string_tag & CBS_ASN1_CONSTRUCTED));

	if (depth > kMaxDepth) {
	return 0;
	}

	while (CBS_len(in) > 0) {
	CBS contents;
	unsigned tag, child_string_tag = string_tag;
	size_t header_len;
	CBB *out_contents, out_contents_storage;

	if (!CBS_get_any_ber_asn1_element(in, &contents, &tag, &header_len)) {
	return 0;
	}

	if (is_eoc(header_len, &contents)) {
	return looking_for_eoc;
	}

	if (string_tag != 0) {
	// This is part of a constructed string. All elements must match
	// \|string_tag\| up to the constructed bit and get appended to \|out\|
	// without a child element.
	if ((tag & ~CBS_ASN1_CONSTRUCTED) != string_tag) {
	return 0;
	}
	out_contents = out;
	} else {
	unsigned out_tag = tag;
	if ((tag & CBS_ASN1_CONSTRUCTED) && is_string_type(tag)) {
	// If a constructed string, clear the constructed bit and inform
	// children to concatenate bodies.
	out_tag &= ~CBS_ASN1_CONSTRUCTED;
	child_string_tag = out_tag;
	}
	if (!CBB_add_asn1(out, &out_contents_storage, out_tag)) {
	return 0;
	}
	out_contents = &out_contents_storage;
	}

	if (CBS_len(&contents) == header_len && header_len > 0 &&
	CBS_data(&contents)[header_len - 1] == 0x80) {
	// This is an indefinite length element.
	if (!cbs_convert_ber(in, out_contents, child_string_tag,
	1 /* looking for eoc */, depth + 1) \|\|
	!CBB_flush(out)) {
	return 0;
	}
	continue;
	}

	if (!CBS_skip(&contents, header_len)) {
	return 0;
	}

	if (tag & CBS_ASN1_CONSTRUCTED) {
	// Recurse into children.
	if (!cbs_convert_ber(&contents, out_contents, child_string_tag,
	0 /* not looking for eoc */, depth + 1)) {
	return 0;
	}
	} else {
	// Copy primitive contents as-is.
	if (!CBB_add_bytes(out_contents, CBS_data(&contents),
	CBS_len(&contents))) {
	return 0;
	}
	}

	if (!CBB_flush(out)) {
	return 0;
	}
	}

	return looking_for_eoc == 0;
	}

	int CBS_asn1_ber_to_der(CBS in, CBS out, uint8_t **out_storage) {
	CBB cbb;

	// First, do a quick walk to find any indefinite-length elements. Most of the
	// time we hope that there aren't any and thus we can quickly return.
	char conversion_needed;
	if (!cbs_find_ber(in, &conversion_needed, 0)) {
	return 0;
	}

	if (!conversion_needed) {
	if (!CBS_get_any_asn1_element(in, out, NULL, NULL)) {
	return 0;
	}
	*out_storage = NULL;
	return 1;
	}

	size_t len;
	if (!CBB_init(&cbb, CBS_len(in)) \|\|
	!cbs_convert_ber(in, &cbb, 0, 0, 0) \|\|
	!CBB_finish(&cbb, out_storage, &len)) {
	CBB_cleanup(&cbb);
	return 0;
	}

	CBS_init(out, *out_storage, len);
	return 1;
	}

	int CBS_get_asn1_implicit_string(CBS in, CBS out, uint8_t **out_storage,
	unsigned outer_tag, unsigned inner_tag) {
	assert(!(outer_tag & CBS_ASN1_CONSTRUCTED));
	assert(!(inner_tag & CBS_ASN1_CONSTRUCTED));
	assert(is_string_type(inner_tag));

	if (CBS_peek_asn1_tag(in, outer_tag)) {
	// Normal implicitly-tagged string.
	*out_storage = NULL;
	return CBS_get_asn1(in, out, outer_tag);
	}

	// Otherwise, try to parse an implicitly-tagged constructed string.
	// \|CBS_asn1_ber_to_der\| is assumed to have run, so only allow one level deep
	// of nesting.
	CBB result;
	CBS child;
	if (!CBB_init(&result, CBS_len(in)) \|\|
	!CBS_get_asn1(in, &child, outer_tag \| CBS_ASN1_CONSTRUCTED)) {
	goto err;
	}

	while (CBS_len(&child) > 0) {
	CBS chunk;
	if (!CBS_get_asn1(&child, &chunk, inner_tag) \|\|
	!CBB_add_bytes(&result, CBS_data(&chunk), CBS_len(&chunk))) {
	goto err;
	}
	}

	uint8_t *data;
	size_t len;
	if (!CBB_finish(&result, &data, &len)) {
	goto err;
	}

	CBS_init(out, data, len);
	*out_storage = data;
	return 1;

	err:
	CBB_cleanup(&result);
	return 0;
	}