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/*
* keyid.c - Routines to calculate key IDs.
*
* Jonathan McDowell <noodles@earth.li>
*
* Copyright 2002 Project Purple
*/
#include <sys/types.h>
#include "keyid.h"
#include "keystructs.h"
#include "log.h"
#include "md5.h"
#include "sha1.h"
/**
* get_keyid - Given a public key returns the keyid.
* @publickey: The key to calculate the id for.
*/
uint64_t get_keyid(struct openpgp_publickey *publickey)
{
return (get_packetid(publickey->publickey));
}
/**
* get_fingerprint - Given a public key returns the fingerprint.
* @publickey: The key to calculate the id for.
* @fingerprint: The fingerprint (must be at least 20 bytes of space).
* @len: The length of the returned fingerprint.
*
* This function returns the fingerprint for a given public key. As Type 3
* fingerprints are 16 bytes and Type 4 are 20 the len field indicates
* which we've returned.
*/
unsigned char *get_fingerprint(struct openpgp_packet *packet,
unsigned char *fingerprint,
size_t *len)
{
SHA1_CTX sha_ctx;
struct md5_ctx md5_context;
unsigned char c;
size_t modlen, explen;
log_assert(fingerprint != NULL);
log_assert(len != NULL);
*len = 0;
switch (packet->data[0]) {
case 2:
case 3:
md5_init_ctx(&md5_context);
/*
* MD5 the modulus and exponent.
*/
modlen = ((packet->data[8] << 8) +
packet->data[9] + 7) >> 3;
md5_process_bytes(&packet->data[10], modlen, &md5_context);
explen = ((packet->data[10+modlen] << 8) +
packet->data[11+modlen] + 7) >> 3;
md5_process_bytes(&packet->data[12 + modlen], explen,
&md5_context);
md5_finish_ctx(&md5_context, fingerprint);
*len = 16;
break;
case 4:
SHA1Init(&sha_ctx);
/*
* TODO: Can this be 0x99? Are all public key packets old
* format with 2 bytes of length data?
*/
c = 0x99;
SHA1Update(&sha_ctx, &c, sizeof(c));
c = packet->length >> 8;
SHA1Update(&sha_ctx, &c, sizeof(c));
c = packet->length & 0xFF;
SHA1Update(&sha_ctx, &c, sizeof(c));
SHA1Update(&sha_ctx, packet->data,
packet->length);
SHA1Final(fingerprint, &sha_ctx);
*len = 20;
break;
default:
logthing(LOGTHING_ERROR, "Unknown key type: %d",
packet->data[0]);
}
return fingerprint;
}
/**
* get_packetid - Given a PGP packet returns the keyid.
* @packet: The packet to calculate the id for.
*/
uint64_t get_packetid(struct openpgp_packet *packet)
{
uint64_t keyid = 0;
int offset = 0;
int i = 0;
size_t length = 0;
unsigned char buff[20];
log_assert(packet != NULL);
switch (packet->data[0]) {
case 2:
case 3:
/*
* For a type 2 or 3 key the keyid is the last 64 bits of the
* public modulus n, which is stored as an MPI from offset 8
* onwards.
*/
offset = (packet->data[8] << 8) +
packet->data[9];
offset = ((offset + 7) / 8) + 2;
for (keyid = 0, i = 0; i < 8; i++) {
keyid <<= 8;
keyid += packet->data[offset++];
}
/*
* Check for an RSA key; if not then log but accept anyway.
* 1 == RSA
* 2 == RSA Encrypt-Only
* 3 == RSA Sign-Only
*/
if (packet->data[7] < 1 || packet->data[7] > 3) {
logthing(LOGTHING_NOTICE,
"Type 2 or 3 key, but not RSA: %llx (type %d)",
keyid,
packet->data[7]);
}
break;
case 4:
get_fingerprint(packet, buff, &length);
for (keyid = 0, i = 12; i < 20; i++) {
keyid <<= 8;
keyid += buff[i];
}
break;
default:
logthing(LOGTHING_ERROR, "Unknown key type: %d",
packet->data[0]);
}
return keyid;
}
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