mirror of
git://git.gnupg.org/gnupg.git
synced 2024-11-04 20:38:50 +01:00
bdb9c2b314
* kbx/keybox-openpgp.c (parse_key): Use algo constants and add experimental support for EdDSA.
519 lines
15 KiB
C
519 lines
15 KiB
C
/* keybox-openpgp.c - OpenPGP key parsing
|
|
* Copyright (C) 2001, 2003, 2011 Free Software Foundation, Inc.
|
|
*
|
|
* This file is part of GnuPG.
|
|
*
|
|
* GnuPG is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License as published by
|
|
* the Free Software Foundation; either version 3 of the License, or
|
|
* (at your option) any later version.
|
|
*
|
|
* GnuPG is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License
|
|
* along with this program; if not, see <http://www.gnu.org/licenses/>.
|
|
*/
|
|
|
|
/* This is a simple OpenPGP parser suitable for all OpenPGP key
|
|
material. It just provides the functionality required to build and
|
|
parse an KBX OpenPGP key blob. Thus it is not a complete parser.
|
|
However it is self-contained and optimized for fast in-memory
|
|
parsing. Note that we don't support old ElGamal v3 keys
|
|
anymore. */
|
|
|
|
#include <config.h>
|
|
#include <stdlib.h>
|
|
#include <stdio.h>
|
|
#include <string.h>
|
|
#include <errno.h>
|
|
#include <assert.h>
|
|
|
|
#include "keybox-defs.h"
|
|
|
|
#include <gcrypt.h>
|
|
|
|
#include "../common/openpgpdefs.h"
|
|
|
|
|
|
/* Assume a valid OpenPGP packet at the address pointed to by BUFBTR
|
|
which has a maximum length as stored at BUFLEN. Return the header
|
|
information of that packet and advance the pointer stored at BUFPTR
|
|
to the next packet; also adjust the length stored at BUFLEN to
|
|
match the remaining bytes. If there are no more packets, store NULL
|
|
at BUFPTR. Return an non-zero error code on failure or the
|
|
following data on success:
|
|
|
|
R_DATAPKT = Pointer to the begin of the packet data.
|
|
R_DATALEN = Length of this data. This has already been checked to fit
|
|
into the buffer.
|
|
R_PKTTYPE = The packet type.
|
|
R_NTOTAL = The total number of bytes of this packet
|
|
|
|
Note that these values are only updated on success.
|
|
*/
|
|
static gpg_error_t
|
|
next_packet (unsigned char const **bufptr, size_t *buflen,
|
|
unsigned char const **r_data, size_t *r_datalen, int *r_pkttype,
|
|
size_t *r_ntotal)
|
|
{
|
|
const unsigned char *buf = *bufptr;
|
|
size_t len = *buflen;
|
|
int c, ctb, pkttype;
|
|
unsigned long pktlen;
|
|
|
|
if (!len)
|
|
return gpg_error (GPG_ERR_NO_DATA);
|
|
|
|
ctb = *buf++; len--;
|
|
if ( !(ctb & 0x80) )
|
|
return gpg_error (GPG_ERR_INV_PACKET); /* Invalid CTB. */
|
|
|
|
pktlen = 0;
|
|
if ((ctb & 0x40)) /* New style (OpenPGP) CTB. */
|
|
{
|
|
pkttype = (ctb & 0x3f);
|
|
if (!len)
|
|
return gpg_error (GPG_ERR_INV_PACKET); /* No 1st length byte. */
|
|
c = *buf++; len--;
|
|
if (pkttype == PKT_COMPRESSED)
|
|
return gpg_error (GPG_ERR_UNEXPECTED); /* ... packet in a keyblock. */
|
|
if ( c < 192 )
|
|
pktlen = c;
|
|
else if ( c < 224 )
|
|
{
|
|
pktlen = (c - 192) * 256;
|
|
if (!len)
|
|
return gpg_error (GPG_ERR_INV_PACKET); /* No 2nd length byte. */
|
|
c = *buf++; len--;
|
|
pktlen += c + 192;
|
|
}
|
|
else if (c == 255)
|
|
{
|
|
if (len <4 )
|
|
return gpg_error (GPG_ERR_INV_PACKET); /* No length bytes. */
|
|
pktlen = (*buf++) << 24;
|
|
pktlen |= (*buf++) << 16;
|
|
pktlen |= (*buf++) << 8;
|
|
pktlen |= (*buf++);
|
|
len -= 4;
|
|
}
|
|
else /* Partial length encoding is not allowed for key packets. */
|
|
return gpg_error (GPG_ERR_UNEXPECTED);
|
|
}
|
|
else /* Old style CTB. */
|
|
{
|
|
int lenbytes;
|
|
|
|
pktlen = 0;
|
|
pkttype = (ctb>>2)&0xf;
|
|
lenbytes = ((ctb&3)==3)? 0 : (1<<(ctb & 3));
|
|
if (!lenbytes) /* Not allowed in key packets. */
|
|
return gpg_error (GPG_ERR_UNEXPECTED);
|
|
if (len < lenbytes)
|
|
return gpg_error (GPG_ERR_INV_PACKET); /* Not enough length bytes. */
|
|
for (; lenbytes; lenbytes--)
|
|
{
|
|
pktlen <<= 8;
|
|
pktlen |= *buf++; len--;
|
|
}
|
|
}
|
|
|
|
/* Do some basic sanity check. */
|
|
switch (pkttype)
|
|
{
|
|
case PKT_SIGNATURE:
|
|
case PKT_SECRET_KEY:
|
|
case PKT_PUBLIC_KEY:
|
|
case PKT_SECRET_SUBKEY:
|
|
case PKT_MARKER:
|
|
case PKT_RING_TRUST:
|
|
case PKT_USER_ID:
|
|
case PKT_PUBLIC_SUBKEY:
|
|
case PKT_OLD_COMMENT:
|
|
case PKT_ATTRIBUTE:
|
|
case PKT_COMMENT:
|
|
case PKT_GPG_CONTROL:
|
|
break; /* Okay these are allowed packets. */
|
|
default:
|
|
return gpg_error (GPG_ERR_UNEXPECTED);
|
|
}
|
|
|
|
if (pktlen == (unsigned long)(-1))
|
|
return gpg_error (GPG_ERR_INV_PACKET);
|
|
|
|
if (pktlen > len)
|
|
return gpg_error (GPG_ERR_INV_PACKET); /* Packet length header too long. */
|
|
|
|
*r_data = buf;
|
|
*r_datalen = pktlen;
|
|
*r_pkttype = pkttype;
|
|
*r_ntotal = (buf - *bufptr) + pktlen;
|
|
|
|
*bufptr = buf + pktlen;
|
|
*buflen = len - pktlen;
|
|
if (!*buflen)
|
|
*bufptr = NULL;
|
|
|
|
return 0;
|
|
}
|
|
|
|
|
|
/* Parse a key packet and store the information in KI. */
|
|
static gpg_error_t
|
|
parse_key (const unsigned char *data, size_t datalen,
|
|
struct _keybox_openpgp_key_info *ki)
|
|
{
|
|
gpg_error_t err;
|
|
const unsigned char *data_start = data;
|
|
int i, version, algorithm;
|
|
size_t n;
|
|
int npkey;
|
|
unsigned char hashbuffer[768];
|
|
const unsigned char *mpi_n = NULL;
|
|
size_t mpi_n_len = 0, mpi_e_len = 0;
|
|
gcry_md_hd_t md;
|
|
int is_ecc = 0;
|
|
|
|
if (datalen < 5)
|
|
return gpg_error (GPG_ERR_INV_PACKET);
|
|
version = *data++; datalen--;
|
|
if (version < 2 || version > 4 )
|
|
return gpg_error (GPG_ERR_INV_PACKET); /* Invalid version. */
|
|
|
|
/*timestamp = ((data[0]<<24)|(data[1]<<16)|(data[2]<<8)|(data[3]));*/
|
|
data +=4; datalen -=4;
|
|
|
|
if (version < 4)
|
|
{
|
|
if (datalen < 2)
|
|
return gpg_error (GPG_ERR_INV_PACKET);
|
|
data +=2; datalen -= 2;
|
|
}
|
|
|
|
if (!datalen)
|
|
return gpg_error (GPG_ERR_INV_PACKET);
|
|
algorithm = *data++; datalen--;
|
|
|
|
switch (algorithm)
|
|
{
|
|
case PUBKEY_ALGO_RSA:
|
|
case PUBKEY_ALGO_RSA_E:
|
|
case PUBKEY_ALGO_RSA_S:
|
|
npkey = 2;
|
|
break;
|
|
case PUBKEY_ALGO_ELGAMAL_E:
|
|
case PUBKEY_ALGO_ELGAMAL:
|
|
npkey = 3;
|
|
break;
|
|
case PUBKEY_ALGO_DSA:
|
|
npkey = 4;
|
|
break;
|
|
case PUBKEY_ALGO_ECDH:
|
|
npkey = 3;
|
|
is_ecc = 1;
|
|
break;
|
|
case PUBKEY_ALGO_ECDSA:
|
|
case PUBKEY_ALGO_EDDSA:
|
|
npkey = 2;
|
|
is_ecc = 1;
|
|
break;
|
|
default: /* Unknown algorithm. */
|
|
return gpg_error (GPG_ERR_UNKNOWN_ALGORITHM);
|
|
}
|
|
|
|
ki->algo = algorithm;
|
|
|
|
for (i=0; i < npkey; i++ )
|
|
{
|
|
unsigned int nbits, nbytes;
|
|
|
|
if (datalen < 2)
|
|
return gpg_error (GPG_ERR_INV_PACKET);
|
|
|
|
if (is_ecc && (i == 0 || i == 2))
|
|
{
|
|
nbytes = data[0];
|
|
if (nbytes < 2 || nbytes > 254)
|
|
return gpg_error (GPG_ERR_INV_PACKET);
|
|
nbytes++; /* The size byte itself. */
|
|
if (datalen < nbytes)
|
|
return gpg_error (GPG_ERR_INV_PACKET);
|
|
}
|
|
else
|
|
{
|
|
nbits = ((data[0]<<8)|(data[1]));
|
|
data += 2;
|
|
datalen -= 2;
|
|
nbytes = (nbits+7) / 8;
|
|
if (datalen < nbytes)
|
|
return gpg_error (GPG_ERR_INV_PACKET);
|
|
/* For use by v3 fingerprint calculation we need to know the RSA
|
|
modulus and exponent. */
|
|
if (i==0)
|
|
{
|
|
mpi_n = data;
|
|
mpi_n_len = nbytes;
|
|
}
|
|
else if (i==1)
|
|
mpi_e_len = nbytes;
|
|
}
|
|
|
|
data += nbytes; datalen -= nbytes;
|
|
}
|
|
n = data - data_start;
|
|
|
|
if (version < 4)
|
|
{
|
|
/* We do not support any other algorithm than RSA in v3
|
|
packets. */
|
|
if (algorithm < 1 || algorithm > 3)
|
|
return gpg_error (GPG_ERR_UNSUPPORTED_ALGORITHM);
|
|
|
|
err = gcry_md_open (&md, GCRY_MD_MD5, 0);
|
|
if (err)
|
|
return err; /* Oops */
|
|
gcry_md_write (md, mpi_n, mpi_n_len);
|
|
gcry_md_write (md, mpi_n+mpi_n_len+2, mpi_e_len);
|
|
memcpy (ki->fpr, gcry_md_read (md, 0), 16);
|
|
gcry_md_close (md);
|
|
ki->fprlen = 16;
|
|
|
|
if (mpi_n_len < 8)
|
|
{
|
|
/* Moduli less than 64 bit are out of the specs scope. Zero
|
|
them out because this is what gpg does too. */
|
|
memset (ki->keyid, 0, 8);
|
|
}
|
|
else
|
|
memcpy (ki->keyid, mpi_n + mpi_n_len - 8, 8);
|
|
}
|
|
else
|
|
{
|
|
/* Its a pitty that we need to prefix the buffer with the tag
|
|
and a length header: We can't simply pass it to the fast
|
|
hashing function for that reason. It might be a good idea to
|
|
have a scatter-gather enabled hash function. What we do here
|
|
is to use a static buffer if this one is large enough and
|
|
only use the regular hash functions if this buffer is not
|
|
large enough. */
|
|
if ( 3 + n < sizeof hashbuffer )
|
|
{
|
|
hashbuffer[0] = 0x99; /* CTB */
|
|
hashbuffer[1] = (n >> 8); /* 2 byte length header. */
|
|
hashbuffer[2] = n;
|
|
memcpy (hashbuffer + 3, data_start, n);
|
|
gcry_md_hash_buffer (GCRY_MD_SHA1, ki->fpr, hashbuffer, 3 + n);
|
|
}
|
|
else
|
|
{
|
|
err = gcry_md_open (&md, GCRY_MD_SHA1, 0);
|
|
if (err)
|
|
return err; /* Oops */
|
|
gcry_md_putc (md, 0x99 ); /* CTB */
|
|
gcry_md_putc (md, (n >> 8) ); /* 2 byte length header. */
|
|
gcry_md_putc (md, n );
|
|
gcry_md_write (md, data_start, n);
|
|
memcpy (ki->fpr, gcry_md_read (md, 0), 20);
|
|
gcry_md_close (md);
|
|
}
|
|
ki->fprlen = 20;
|
|
memcpy (ki->keyid, ki->fpr+12, 8);
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
|
|
|
|
/* The caller must pass the address of an INFO structure which will
|
|
get filled on success with information pertaining to the OpenPGP
|
|
keyblock IMAGE of length IMAGELEN. Note that a caller does only
|
|
need to release this INFO structure if the function returns
|
|
success. If NPARSED is not NULL the actual number of bytes parsed
|
|
will be stored at this address. */
|
|
gpg_error_t
|
|
_keybox_parse_openpgp (const unsigned char *image, size_t imagelen,
|
|
size_t *nparsed, keybox_openpgp_info_t info)
|
|
{
|
|
gpg_error_t err = 0;
|
|
const unsigned char *image_start, *data;
|
|
size_t n, datalen;
|
|
int pkttype;
|
|
int first = 1;
|
|
int read_error = 0;
|
|
struct _keybox_openpgp_key_info *k, **ktail = NULL;
|
|
struct _keybox_openpgp_uid_info *u, **utail = NULL;
|
|
|
|
memset (info, 0, sizeof *info);
|
|
if (nparsed)
|
|
*nparsed = 0;
|
|
|
|
image_start = image;
|
|
while (image)
|
|
{
|
|
err = next_packet (&image, &imagelen, &data, &datalen, &pkttype, &n);
|
|
if (err)
|
|
{
|
|
read_error = 1;
|
|
break;
|
|
}
|
|
|
|
if (first)
|
|
{
|
|
if (pkttype == PKT_PUBLIC_KEY)
|
|
;
|
|
else if (pkttype == PKT_SECRET_KEY)
|
|
info->is_secret = 1;
|
|
else
|
|
{
|
|
err = gpg_error (GPG_ERR_UNEXPECTED);
|
|
if (nparsed)
|
|
*nparsed += n;
|
|
break;
|
|
}
|
|
first = 0;
|
|
}
|
|
else if (pkttype == PKT_PUBLIC_KEY || pkttype == PKT_SECRET_KEY)
|
|
break; /* Next keyblock encountered - ready. */
|
|
|
|
if (nparsed)
|
|
*nparsed += n;
|
|
|
|
if (pkttype == PKT_SIGNATURE)
|
|
{
|
|
/* For now we only count the total number of signatures. */
|
|
info->nsigs++;
|
|
}
|
|
else if (pkttype == PKT_USER_ID)
|
|
{
|
|
info->nuids++;
|
|
if (info->nuids == 1)
|
|
{
|
|
info->uids.off = data - image_start;
|
|
info->uids.len = datalen;
|
|
utail = &info->uids.next;
|
|
}
|
|
else
|
|
{
|
|
u = xtrycalloc (1, sizeof *u);
|
|
if (!u)
|
|
{
|
|
err = gpg_error_from_syserror ();
|
|
break;
|
|
}
|
|
u->off = data - image_start;
|
|
u->len = datalen;
|
|
*utail = u;
|
|
utail = &u->next;
|
|
}
|
|
}
|
|
else if (pkttype == PKT_PUBLIC_KEY || pkttype == PKT_SECRET_KEY)
|
|
{
|
|
err = parse_key (data, datalen, &info->primary);
|
|
if (err)
|
|
break;
|
|
}
|
|
else if( pkttype == PKT_PUBLIC_SUBKEY && datalen && *data == '#' )
|
|
{
|
|
/* Early versions of GnuPG used old PGP comment packets;
|
|
* luckily all those comments are prefixed by a hash
|
|
* sign - ignore these packets. */
|
|
}
|
|
else if (pkttype == PKT_PUBLIC_SUBKEY || pkttype == PKT_SECRET_SUBKEY)
|
|
{
|
|
info->nsubkeys++;
|
|
if (info->nsubkeys == 1)
|
|
{
|
|
err = parse_key (data, datalen, &info->subkeys);
|
|
if (err)
|
|
{
|
|
info->nsubkeys--;
|
|
/* We ignore subkeys with unknown algorithms. */
|
|
if (gpg_err_code (err) == GPG_ERR_UNKNOWN_ALGORITHM
|
|
|| gpg_err_code (err) == GPG_ERR_UNSUPPORTED_ALGORITHM)
|
|
err = 0;
|
|
if (err)
|
|
break;
|
|
}
|
|
else
|
|
ktail = &info->subkeys.next;
|
|
}
|
|
else
|
|
{
|
|
k = xtrycalloc (1, sizeof *k);
|
|
if (!k)
|
|
{
|
|
err = gpg_error_from_syserror ();
|
|
break;
|
|
}
|
|
err = parse_key (data, datalen, k);
|
|
if (err)
|
|
{
|
|
xfree (k);
|
|
info->nsubkeys--;
|
|
/* We ignore subkeys with unknown algorithms. */
|
|
if (gpg_err_code (err) == GPG_ERR_UNKNOWN_ALGORITHM
|
|
|| gpg_err_code (err) == GPG_ERR_UNSUPPORTED_ALGORITHM)
|
|
err = 0;
|
|
if (err)
|
|
break;
|
|
}
|
|
else
|
|
{
|
|
*ktail = k;
|
|
ktail = &k->next;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
if (err)
|
|
{
|
|
_keybox_destroy_openpgp_info (info);
|
|
if (!read_error)
|
|
{
|
|
/* Packet parsing worked, thus we should be able to skip the
|
|
rest of the keyblock. */
|
|
while (image)
|
|
{
|
|
if (next_packet (&image, &imagelen,
|
|
&data, &datalen, &pkttype, &n) )
|
|
break; /* Another error - stop here. */
|
|
|
|
if (pkttype == PKT_PUBLIC_KEY || pkttype == PKT_SECRET_KEY)
|
|
break; /* Next keyblock encountered - ready. */
|
|
|
|
if (nparsed)
|
|
*nparsed += n;
|
|
}
|
|
}
|
|
}
|
|
|
|
return err;
|
|
}
|
|
|
|
|
|
/* Release any malloced data in INFO but not INFO itself! */
|
|
void
|
|
_keybox_destroy_openpgp_info (keybox_openpgp_info_t info)
|
|
{
|
|
struct _keybox_openpgp_key_info *k, *k2;
|
|
struct _keybox_openpgp_uid_info *u, *u2;
|
|
|
|
assert (!info->primary.next);
|
|
for (k=info->subkeys.next; k; k = k2)
|
|
{
|
|
k2 = k->next;
|
|
xfree (k);
|
|
}
|
|
|
|
for (u=info->uids.next; u; u = u2)
|
|
{
|
|
u2 = u->next;
|
|
xfree (u);
|
|
}
|
|
}
|