int
pgp_put_uint16(struct nettle_buffer *buffer, unsigned i)
{
uint8_t *p = nettle_buffer_space(buffer, 2);
if (!p)
return 0;
WRITE_UINT16(p, i);
return 1;
}
int
pgp_put_uint32(struct nettle_buffer *buffer, uint32_t i)
{
uint8_t *p = nettle_buffer_space(buffer, 4);
if (!p)
return 0;
WRITE_UINT32(p, i);
return 1;
}
int
pgp_put_mpi(struct nettle_buffer *buffer, const mpz_t x)
{
unsigned bits = mpz_sizeinbase(x, 2);
unsigned octets = (bits + 7) / 8;
uint8_t *p;
/* FIXME: What's the correct representation of zero? */
if (!pgp_put_uint16(buffer, bits))
return 0;
p = nettle_buffer_space(buffer, octets);
if (!p)
return 0;
nettle_mpz_get_str_256(octets, p, x);
return 1;
}
unsigned
sexp_transport_vformat(struct nettle_buffer *buffer,
const char *format, va_list args)
{
unsigned start = 0;
unsigned length;
unsigned base64_length;
if (buffer)
{
if (!NETTLE_BUFFER_PUTC(buffer, '{'))
return 0;
start = buffer->size;
}
length = sexp_vformat(buffer, format, args);
if (!length)
return 0;
base64_length = BASE64_ENCODE_RAW_LENGTH(length);
if (buffer)
{
if (!nettle_buffer_space(buffer, base64_length - length))
return 0;
base64_encode_raw(buffer->contents + start,
length, buffer->contents + start);
if (!NETTLE_BUFFER_PUTC(buffer, '}'))
return 0;
}
return base64_length + 2;
}
int
pgp_armor(struct nettle_buffer *buffer,
const char *tag,
unsigned length,
const uint8_t *data)
{
struct base64_encode_ctx ctx;
unsigned crc = pgp_crc24(length, data);
base64_encode_init(&ctx);
if (! (write_string(buffer, "BEGIN PGP ")
&& write_string(buffer, tag)
&& write_string(buffer, "\nComment: Nettle\n\n")))
return 0;
for (;
length >= BINARY_PER_LINE;
length -= BINARY_PER_LINE, data += BINARY_PER_LINE)
{
unsigned done;
uint8_t *p
= nettle_buffer_space(buffer, TEXT_PER_LINE);
if (!p)
return 0;
done = base64_encode_update(&ctx, p, BINARY_PER_LINE, data);
assert(done <= TEXT_PER_LINE);
/* FIXME: Create some official way to do this */
buffer->size -= (TEXT_PER_LINE - done);
if (!NETTLE_BUFFER_PUTC(buffer, '\n'))
return 0;
}
if (length)
{
unsigned text_size = BASE64_ENCODE_LENGTH(length)
+ BASE64_ENCODE_FINAL_LENGTH;
unsigned done;
uint8_t *p
= nettle_buffer_space(buffer, text_size);
if (!p)
return 0;
done = base64_encode_update(&ctx, p, length, data);
done += base64_encode_final(&ctx, p + done);
/* FIXME: Create some official way to do this */
buffer->size -= (text_size - done);
if (!NETTLE_BUFFER_PUTC(buffer, '\n'))
return 0;
}
/* Checksum */
if (!NETTLE_BUFFER_PUTC(buffer, '='))
return 0;
{
uint8_t *p = nettle_buffer_space(buffer, 4);
if (!p)
return 0;
base64_encode_group(p, crc);
}
return (write_string(buffer, "\nBEGIN PGP ")
&& write_string(buffer, tag)
&& NETTLE_BUFFER_PUTC(buffer, '\n'));
}
int
pgp_put_rsa_sha1_signature(struct nettle_buffer *buffer,
const struct rsa_private_key *key,
const uint8_t *keyid,
unsigned type,
struct sha1_ctx *hash)
{
unsigned signature_start = buffer->size;
unsigned hash_end;
unsigned sub_packet_start;
uint8_t trailer[6];
mpz_t s;
/* Signature packet. The packet could reasonably be both smaller and
* larger than 192, so for simplicity we use the 4 octet header
* form. */
if (! (pgp_put_header(buffer, PGP_TAG_SIGNATURE, PGP_LENGTH_FOUR_OCTETS)
&& NETTLE_BUFFER_PUTC(buffer, 4) /* Version */
&& NETTLE_BUFFER_PUTC(buffer, type)
/* Could also be PGP_RSA_SIGN */
&& NETTLE_BUFFER_PUTC(buffer, PGP_RSA)
&& NETTLE_BUFFER_PUTC(buffer, PGP_SHA1)
&& pgp_put_uint16(buffer, 0))) /* Hashed subpacket length */
return 0;
hash_end = buffer->size;
sha1_update(hash,
hash_end - signature_start,
buffer->contents + signature_start);
trailer[0] = 4; trailer[1] = 0xff;
WRITE_UINT32(trailer + 2, buffer->size - signature_start);
sha1_update(hash, sizeof(trailer), trailer);
{
struct sha1_ctx hcopy = *hash;
uint8_t *p = nettle_buffer_space(buffer, 2);
if (!p)
return 0;
sha1_digest(&hcopy, 2, p);
}
/* One "sub-packet" field with the issuer keyid */
sub_packet_start = pgp_sub_packet_start(buffer);
if (!sub_packet_start)
return 0;
if (pgp_put_sub_packet(buffer, PGP_SUBPACKET_ISSUER_KEY_ID, 8, keyid))
{
pgp_sub_packet_end(buffer, sub_packet_start);
return 0;
}
mpz_init(s);
if (!(rsa_sha1_sign(key, hash, s)
&& pgp_put_mpi(buffer, s)))
{
mpz_clear(s);
return 0;
}
mpz_clear(s);
pgp_put_header_length(buffer, signature_start, 4);
return 1;
}
unsigned
pgp_sub_packet_start(struct nettle_buffer *buffer)
{
return nettle_buffer_space(buffer, 2) ? buffer->size : 0;
}