/* 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_grpc/mem.h> #include <openssl_grpc/bytestring.h> #include <assert.h> #include <inttypes.h> #include <string.h> #include "internal.h" #include "../internal.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) { OPENSSL_free(*out_ptr); *out_ptr = NULL; *out_len = 0; if (cbs->len == 0) { return 1; } *out_ptr = OPENSSL_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) { OPENSSL_free(*out_ptr); } *out_ptr = OPENSSL_strndup((const char*)cbs->data, cbs->len); return (*out_ptr != NULL); } int CBS_contains_zero_byte(const CBS *cbs) { return OPENSSL_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, uint64_t *out, size_t len) { uint64_t result = 0; const uint8_t *data; if (!cbs_get(cbs, &data, len)) { return 0; } for (size_t 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) { uint64_t v; if (!cbs_get_u(cbs, &v, 2)) { return 0; } *out = v; return 1; } int CBS_get_u16le(CBS *cbs, uint16_t *out) { if (!CBS_get_u16(cbs, out)) { return 0; } *out = CRYPTO_bswap2(*out); return 1; } int CBS_get_u24(CBS *cbs, uint32_t *out) { uint64_t v; if (!cbs_get_u(cbs, &v, 3)) { return 0; } *out = v; return 1; } int CBS_get_u32(CBS *cbs, uint32_t *out) { uint64_t v; if (!cbs_get_u(cbs, &v, 4)) { return 0; } *out = v; return 1; } int CBS_get_u32le(CBS *cbs, uint32_t *out) { if (!CBS_get_u32(cbs, out)) { return 0; } *out = CRYPTO_bswap4(*out); return 1; } int CBS_get_u64(CBS *cbs, uint64_t *out) { return cbs_get_u(cbs, out, 8); } int CBS_get_u64le(CBS *cbs, uint64_t *out) { if (!cbs_get_u(cbs, out, 8)) { return 0; } *out = CRYPTO_bswap8(*out); return 1; } int CBS_get_last_u8(CBS *cbs, uint8_t *out) { if (cbs->len == 0) { return 0; } *out = cbs->data[cbs->len - 1]; cbs->len--; return 1; } 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; } int CBS_copy_bytes(CBS *cbs, uint8_t *out, size_t len) { const uint8_t *v; if (!cbs_get(cbs, &v, len)) { return 0; } OPENSSL_memcpy(out, v, len); return 1; } static int cbs_get_length_prefixed(CBS *cbs, CBS *out, size_t len_len) { uint64_t len; if (!cbs_get_u(cbs, &len, len_len)) { return 0; } // If |len_len| <= 3 then we know that |len| will fit into a |size_t|, even on // 32-bit systems. assert(len_len <= 3); 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_until_first(CBS *cbs, CBS *out, uint8_t c) { const uint8_t *split = OPENSSL_memchr(CBS_data(cbs), c, CBS_len(cbs)); if (split == NULL) { return 0; } return CBS_get_bytes(cbs, out, split - CBS_data(cbs)); } // parse_base128_integer reads a big-endian base-128 integer from |cbs| and sets // |*out| to the result. This is the encoding used in DER for both high tag // number form and OID components. static int parse_base128_integer(CBS *cbs, uint64_t *out) { uint64_t v = 0; uint8_t b; do { if (!CBS_get_u8(cbs, &b)) { return 0; } if ((v >> (64 - 7)) != 0) { // The value is too large. return 0; } if (v == 0 && b == 0x80) { // The value must be minimally encoded. return 0; } v = (v << 7) | (b & 0x7f); // Values end at an octet with the high bit cleared. } while (b & 0x80); *out = v; return 1; } static int parse_asn1_tag(CBS *cbs, unsigned *out) { uint8_t tag_byte; if (!CBS_get_u8(cbs, &tag_byte)) { return 0; } // ITU-T X.690 section 8.1.2.3 specifies the format for identifiers with a tag // number no greater than 30. // // If the number portion is 31 (0x1f, the largest value that fits in the // allotted bits), then the tag is more than one byte long and the // continuation bytes contain the tag number. unsigned tag = ((unsigned)tag_byte & 0xe0) << CBS_ASN1_TAG_SHIFT; unsigned tag_number = tag_byte & 0x1f; if (tag_number == 0x1f) { uint64_t v; if (!parse_base128_integer(cbs, &v) || // Check the tag number is within our supported bounds. v > CBS_ASN1_TAG_NUMBER_MASK || // Small tag numbers should have used low tag number form, even in BER. v < 0x1f) { return 0; } tag_number = (unsigned)v; } tag |= tag_number; *out = tag; return 1; } static int cbs_get_any_asn1_element(CBS *cbs, CBS *out, unsigned *out_tag, size_t *out_header_len, int *out_ber_found, int ber_ok) { CBS header = *cbs; CBS throwaway; if (out == NULL) { out = &throwaway; } if (ber_ok) { *out_ber_found = 0; } unsigned tag; if (!parse_asn1_tag(&header, &tag)) { return 0; } if (out_tag != NULL) { *out_tag = tag; } uint8_t length_byte; if (!CBS_get_u8(&header, &length_byte)) { return 0; } size_t header_len = CBS_len(cbs) - CBS_len(&header); size_t len; // The format for the length encoding is specified in ITU-T X.690 section // 8.1.3. if ((length_byte & 0x80) == 0) { // Short form length. len = ((size_t) length_byte) + header_len; if (out_header_len != NULL) { *out_header_len = header_len; } } else { // The high bit indicate that this is the long form, while the next 7 bits // encode the number of subsequent octets used to encode the length (ITU-T // X.690 clause 8.1.3.5.b). const size_t num_bytes = length_byte & 0x7f; uint64_t len64; if (ber_ok && (tag & CBS_ASN1_CONSTRUCTED) != 0 && num_bytes == 0) { // indefinite length if (out_header_len != NULL) { *out_header_len = header_len; } *out_ber_found = 1; return CBS_get_bytes(cbs, out, header_len); } // ITU-T X.690 clause 8.1.3.5.c specifies that the value 0xff shall not be // used as the first byte of the length. If this parser encounters that // value, num_bytes will be parsed as 127, which will fail this check. if (num_bytes == 0 || num_bytes > 4) { return 0; } if (!cbs_get_u(&header, &len64, num_bytes)) { return 0; } // ITU-T X.690 section 10.1 (DER length forms) requires encoding the // length with the minimum number of octets. BER could, technically, have // 125 superfluous zero bytes. We do not attempt to handle that and still // require that the length fit in a |uint32_t| for BER. if (len64 < 128) { // Length should have used short-form encoding. if (ber_ok) { *out_ber_found = 1; } else { return 0; } } if ((len64 >> ((num_bytes - 1) * 8)) == 0) { // Length should have been at least one byte shorter. if (ber_ok) { *out_ber_found = 1; } else { return 0; } } len = len64; if (len + header_len + num_bytes < len) { // Overflow. return 0; } len += header_len + num_bytes; if (out_header_len != NULL) { *out_header_len = header_len + num_bytes; } } return CBS_get_bytes(cbs, out, len); } int CBS_get_any_asn1(CBS *cbs, CBS *out, unsigned *out_tag) { size_t header_len; if (!CBS_get_any_asn1_element(cbs, out, out_tag, &header_len)) { return 0; } if (!CBS_skip(out, header_len)) { assert(0); return 0; } return 1; } int CBS_get_any_asn1_element(CBS *cbs, CBS *out, unsigned *out_tag, size_t *out_header_len) { return cbs_get_any_asn1_element(cbs, out, out_tag, out_header_len, NULL, 0 /* DER only */); } int CBS_get_any_ber_asn1_element(CBS *cbs, CBS *out, unsigned *out_tag, size_t *out_header_len, int *out_ber_found) { int ber_found_temp; return cbs_get_any_asn1_element( cbs, out, out_tag, out_header_len, out_ber_found ? out_ber_found : &ber_found_temp, 1 /* BER allowed */); } 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) { 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; } CBS copy = *cbs; unsigned actual_tag; return parse_asn1_tag(©, &actual_tag) && tag_value == actual_tag; } int CBS_get_asn1_uint64(CBS *cbs, uint64_t *out) { CBS bytes; if (!CBS_get_asn1(cbs, &bytes, CBS_ASN1_INTEGER) || !CBS_is_unsigned_asn1_integer(&bytes)) { return 0; } *out = 0; const uint8_t *data = CBS_data(&bytes); size_t len = CBS_len(&bytes); for (size_t 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_asn1_int64(CBS *cbs, int64_t *out) { int is_negative; CBS bytes; if (!CBS_get_asn1(cbs, &bytes, CBS_ASN1_INTEGER) || !CBS_is_valid_asn1_integer(&bytes, &is_negative)) { return 0; } const uint8_t *data = CBS_data(&bytes); const size_t len = CBS_len(&bytes); if (len > sizeof(int64_t)) { return 0; } union { int64_t i; uint8_t bytes[sizeof(int64_t)]; } u; memset(u.bytes, is_negative ? 0xff : 0, sizeof(u.bytes)); // Sign-extend. for (size_t i = 0; i < len; i++) { u.bytes[i] = data[len - i - 1]; } *out = u.i; return 1; } int CBS_get_asn1_bool(CBS *cbs, int *out) { CBS bytes; if (!CBS_get_asn1(cbs, &bytes, CBS_ASN1_BOOLEAN) || CBS_len(&bytes) != 1) { return 0; } const uint8_t value = *CBS_data(&bytes); if (value != 0 && value != 0xff) { return 0; } *out = !!value; return 1; } int CBS_get_optional_asn1(CBS *cbs, CBS *out, int *out_present, unsigned tag) { int present = 0; if (CBS_peek_asn1_tag(cbs, tag)) { if (!CBS_get_asn1(cbs, out, tag)) { return 0; } present = 1; } if (out_present != NULL) { *out_present = present; } 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) { assert(out); 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; } int CBS_is_valid_asn1_bitstring(const CBS *cbs) { CBS in = *cbs; uint8_t num_unused_bits; if (!CBS_get_u8(&in, &num_unused_bits) || num_unused_bits > 7) { return 0; } if (num_unused_bits == 0) { return 1; } // All num_unused_bits bits must exist and be zeros. uint8_t last; if (!CBS_get_last_u8(&in, &last) || (last & ((1 << num_unused_bits) - 1)) != 0) { return 0; } return 1; } int CBS_asn1_bitstring_has_bit(const CBS *cbs, unsigned bit) { if (!CBS_is_valid_asn1_bitstring(cbs)) { return 0; } const unsigned byte_num = (bit >> 3) + 1; const unsigned bit_num = 7 - (bit & 7); // Unused bits are zero, and this function does not distinguish between // missing and unset bits. Thus it is sufficient to do a byte-level length // check. return byte_num < CBS_len(cbs) && (CBS_data(cbs)[byte_num] & (1 << bit_num)) != 0; } int CBS_is_valid_asn1_integer(const CBS *cbs, int *out_is_negative) { CBS copy = *cbs; uint8_t first_byte, second_byte; if (!CBS_get_u8(©, &first_byte)) { return 0; // INTEGERs may not be empty. } if (out_is_negative != NULL) { *out_is_negative = (first_byte & 0x80) != 0; } if (!CBS_get_u8(©, &second_byte)) { return 1; // One byte INTEGERs are always minimal. } if ((first_byte == 0x00 && (second_byte & 0x80) == 0) || (first_byte == 0xff && (second_byte & 0x80) != 0)) { return 0; // The value is minimal iff the first 9 bits are not all equal. } return 1; } int CBS_is_unsigned_asn1_integer(const CBS *cbs) { int is_negative; return CBS_is_valid_asn1_integer(cbs, &is_negative) && !is_negative; } static int add_decimal(CBB *out, uint64_t v) { char buf[DECIMAL_SIZE(uint64_t) + 1]; BIO_snprintf(buf, sizeof(buf), "%" PRIu64, v); return CBB_add_bytes(out, (const uint8_t *)buf, strlen(buf)); } char *CBS_asn1_oid_to_text(const CBS *cbs) { CBB cbb; if (!CBB_init(&cbb, 32)) { goto err; } CBS copy = *cbs; // The first component is 40 * value1 + value2, where value1 is 0, 1, or 2. uint64_t v; if (!parse_base128_integer(©, &v)) { goto err; } if (v >= 80) { if (!CBB_add_bytes(&cbb, (const uint8_t *)"2.", 2) || !add_decimal(&cbb, v - 80)) { goto err; } } else if (!add_decimal(&cbb, v / 40) || !CBB_add_u8(&cbb, '.') || !add_decimal(&cbb, v % 40)) { goto err; } while (CBS_len(©) != 0) { if (!parse_base128_integer(©, &v) || !CBB_add_u8(&cbb, '.') || !add_decimal(&cbb, v)) { goto err; } } uint8_t *txt; size_t txt_len; if (!CBB_add_u8(&cbb, '\0') || !CBB_finish(&cbb, &txt, &txt_len)) { goto err; } return (char *)txt; err: CBB_cleanup(&cbb); return NULL; }