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openpgp: Rewrite decipher/derive to use asn1 functions

This commit is contained in:
Jakub Jelen 2020-05-22 11:55:22 +02:00
parent cb8c7647ca
commit ae771a135f
1 changed files with 42 additions and 24 deletions
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66
src/libopensc/card-openpgp.c
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@ -2231,14 +2231,16 @@ pgp_decipher(sc_card_t *card, const u8 *in, size_t inlen,
sc_security_env_t *env = &priv->sec_env;
sc_apdu_t apdu;
u8 apdu_case = SC_APDU_CASE_4;
u8 *temp = NULL;
int r, extlen = 0;
u8 *temp = NULL, *p = NULL;
size_t templen, pklen, dolen;
int r;
LOG_FUNC_CALLED(card->ctx);
/* padding according to OpenPGP card spec 1.1 & 2.x section 7.2.9 / 3.x section 7.2.11
* The longest possible prefix is 10 bytes for ECDH */
if (!(temp = malloc(inlen + 10)))
templen = inlen + 10;
if (!(temp = malloc(templen)))
LOG_FUNC_RETURN(card->ctx, SC_ERROR_OUT_OF_MEMORY);
/* padding byte: 0xa6 = ECC; 0x00 = RSA; 0x02 = AES */
@ -2248,48 +2250,64 @@ pgp_decipher(sc_card_t *card, const u8 *in, size_t inlen,
* provided by the padding routines. But it lets put it here
* to make sure it does not conflict with following indicators */
temp[0] = 0x00;
extlen = 1;
memcpy(temp + 1, in, inlen);
inlen += 1;
break;
case SC_ALGORITHM_EC:
case SC_ALGORITHM_XEDDSA:
/* Calculate length of External Public Key (0x86) */
r = sc_asn1_put_tag(0x86, NULL, inlen, NULL, 0, NULL);
if (r <= 0) {
free(temp);
LOG_FUNC_RETURN(card->ctx, r);
}
pklen = r;
/* Calculate lenght of Public Key DO (0x7F49) */
r = sc_asn1_put_tag(0x7f49, NULL, pklen, NULL, 0, NULL);
if (r <= 0) {
free(temp);
LOG_FUNC_RETURN(card->ctx, r);
}
dolen = r;
p = temp;
/* This is 0xA6 Cipher DO with associated length field */
temp[extlen++] = 0xa6;
if (inlen >= 128) {
temp[extlen++] = 0x81;
temp[extlen++] = inlen + 7;
} else {
temp[extlen++] = inlen + 5;
r = sc_asn1_put_tag(0xA6, NULL, dolen, p, templen - (p - temp), &p);
if (r != SC_SUCCESS) {
free(temp);
LOG_FUNC_RETURN(card->ctx, r);
}
/* Public Key DO (0x7F49) with associated length field */
temp[extlen++] = 0x7f;
temp[extlen++] = 0x49;
if (inlen >= 128) {
temp[extlen++] = 0x81;
temp[extlen++] = inlen + 3;
} else {
temp[extlen++] = inlen + 2;
r = sc_asn1_put_tag(0x7F49, NULL, pklen, p, templen - (p - temp), &p);
if (r != SC_SUCCESS) {
free(temp);
LOG_FUNC_RETURN(card->ctx, r);
}
/* External Public Key (0x86) with associated length */
temp[extlen++] = 0x86;
if (inlen >= 128) {
temp[extlen++] = 0x81;
r = sc_asn1_put_tag(0x86, in, inlen, p, templen - (p - temp), &p);
if (r != SC_SUCCESS) {
free(temp);
LOG_FUNC_RETURN(card->ctx, r);
}
temp[extlen++] = inlen;
inlen = (p - temp);
break;
case SC_ALGORITHM_AES:
/* not supported yet */
/*
temp[0] = 0x02;
extlen = 1;
memcpy(temp + 1, in, inlen);
inlen += 1;
*/
/* fall through */
default:
LOG_FUNC_RETURN(card->ctx, SC_ERROR_INVALID_ARGUMENTS);
}
memcpy(temp + extlen, in, inlen);
in = temp;
inlen += extlen;
if (env->operation != SC_SEC_OPERATION_DECIPHER &&
env->operation != SC_SEC_OPERATION_DERIVE) {