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iso-sm: avoid allocation of big chunk of data 

Use unencrypted APDU's resplen to estimate the size of the required SM
response buffer
This commit is contained in:
Frank Morgner 2018-12-12 21:25:52 +01:00
parent 6f0f42c506
commit aa940e8619
1 changed files with 9 additions and 24 deletions
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33
src/sm/sm-iso.c
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@ -279,7 +279,7 @@ static int sm_encrypt(const struct iso_sm_ctx *ctx, sc_card_t *card,
u8 *p, *le = NULL, *sm_data = NULL, *fdata = NULL, *mac_data = NULL,
*asn1 = NULL, *mac = NULL, *resp_data = NULL;
size_t sm_data_len, fdata_len, mac_data_len, asn1_len, mac_len, le_len;
int r, cse;
int r;
sc_apdu_t *sm_apdu = NULL;
if (!apdu || !ctx || !card || !card->reader || !psm_apdu) {
@ -313,17 +313,7 @@ static int sm_encrypt(const struct iso_sm_ctx *ctx, sc_card_t *card,
}
mac_data_len = r;
/* get le and data depending on the case of the insecure command */
cse = apdu->cse;
if ((apdu->le/ctx->block_length + 1)*ctx->block_length + 18 > 0xff+1)
/* for encrypted APDUs we usually get authenticated status bytes (4B),
* a MAC (11B) and a cryptogram with padding indicator (3B without
* data). The cryptogram is always padded to the block size. */
/*cse |= SC_APDU_EXT;*/
sc_debug(card->ctx, SC_LOG_DEBUG_VERBOSE,
"Response data may be truncated, because it doesn't fit into a short length APDU.");
switch (cse) {
switch (apdu->cse) {
case SC_APDU_CASE_1:
break;
case SC_APDU_CASE_2_SHORT:
@ -476,22 +466,17 @@ static int sm_encrypt(const struct iso_sm_ctx *ctx, sc_card_t *card,
sm_apdu->datalen = sm_data_len;
sm_apdu->lc = sm_data_len;
sm_apdu->le = 0;
if (cse & SC_APDU_EXT) {
if (apdu->cse & SC_APDU_EXT) {
sm_apdu->cse = SC_APDU_CASE_4_EXT;
#if OPENSC_NOT_BOGUS_ANYMORE
sm_apdu->resplen = 0xffff+1;
#else
sm_apdu->resplen = SC_MAX_EXT_APDU_BUFFER_SIZE;
#endif
} else {
sm_apdu->cse = SC_APDU_CASE_4_SHORT;
#if OPENSC_NOT_BOGUS_ANYMORE
sm_apdu->resplen = 0xff+1;
#else
sm_apdu->resplen = SC_MAX_APDU_BUFFER_SIZE;
#endif
}
resp_data = calloc(sm_apdu->resplen);
/* for encrypted APDUs we usually get authenticated status bytes
* (4B), a MAC (2B without data) and a cryptogram with padding
* indicator (3B without data). The cryptogram is always padded to
* the block size. */
sm_apdu->resplen = 9 + mac_len + (apdu->resplen/ctx->block_length + 1)*ctx->block_length;
resp_data = calloc(sm_apdu->resplen, 1);
if (!resp_data) {
r = SC_ERROR_OUT_OF_MEMORY;
goto err;