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scd:openpgp: Fix writing ECC key to card. 

* scd/app-openpgp.c (build_privkey_template): Adding another argument
of ecc_d_fixed_len to handle variable-size MPI.

--

GnuPG-bug-id: 5163
Signed-off-by: NIIBE Yutaka <gniibe@fsij.org>
This commit is contained in:
NIIBE Yutaka 2020-12-03 15:04:14 +09:00
parent 63ed2054a1
commit a25c99b156
1 changed files with 27 additions and 6 deletions
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33
scd/app-openpgp.c
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@ -3711,6 +3711,7 @@ build_privkey_template (app_t app, int keyno,
static gpg_error_t
build_ecc_privkey_template (app_t app, int keyno,
const unsigned char *ecc_d, size_t ecc_d_len,
size_t ecc_d_fixed_len,
const unsigned char *ecc_q, size_t ecc_q_len,
unsigned char **result, size_t *resultlen)
{
@ -3726,6 +3727,18 @@ build_ecc_privkey_template (app_t app, int keyno,
size_t template_size;
int pubkey_required;
/* This case doesn't occur in GnuPG 2.3 or later, because
agent/sexp-secret.c does the fixup. */
if (ecc_d_fixed_len < ecc_d_len)
{
if (ecc_d_fixed_len != ecc_d_len - 1 || *ecc_d)
return gpg_error (GPG_ERR_INV_OBJ);
/* Remove the additional zero. */
ecc_d_len--;
ecc_d++;
}
pubkey_required = !!(app->app_local->keyattr[keyno].ecc.flags
& ECC_FLAG_PUBKEY);
@ -3736,8 +3749,8 @@ build_ecc_privkey_template (app_t app, int keyno,
datalen = 0;
tp = privkey;
tp += add_tlv (tp, 0x92, ecc_d_len);
datalen += ecc_d_len;
tp += add_tlv (tp, 0x92, ecc_d_fixed_len);
datalen += ecc_d_fixed_len;
if (pubkey_required)
{
@ -3780,8 +3793,14 @@ build_ecc_privkey_template (app_t app, int keyno,
memcpy (tp, suffix, suffix_len);
tp += suffix_len;
memcpy (tp, ecc_d, ecc_d_len);
tp += ecc_d_len;
if (ecc_d_fixed_len > ecc_d_len)
{
memset (tp, 0, ecc_d_fixed_len - ecc_d_len);
memcpy (tp + ecc_d_fixed_len - ecc_d_len, ecc_d, ecc_d_len);
}
else
memcpy (tp, ecc_d, ecc_d_len);
tp += ecc_d_fixed_len;
if (pubkey_required)
{
@ -4406,6 +4425,7 @@ ecc_writekey (app_t app, ctrl_t ctrl,
unsigned int n;
size_t oid_len;
unsigned char fprbuf[20];
size_t ecc_d_fixed_len;
/* (private-key(ecc(curve%s)(q%m)(d%m))(created-at%d)):
curve = "NIST P-256" */
@ -4548,7 +4568,8 @@ ecc_writekey (app_t app, ctrl_t ctrl,
else
algo = PUBKEY_ALGO_ECDSA;
oidstr = openpgp_curve_to_oid (curve, NULL, NULL);
oidstr = openpgp_curve_to_oid (curve, &n, NULL);
ecc_d_fixed_len = (n+7)/8;
err = openpgp_oid_from_str (oidstr, &oid);
if (err)
goto leave;
@ -4614,7 +4635,7 @@ ecc_writekey (app_t app, ctrl_t ctrl,
int exmode;
err = build_ecc_privkey_template (app, keyno,
ecc_d, ecc_d_len,
ecc_d, ecc_d_len, ecc_d_fixed_len,
ecc_q, ecc_q_len,
&template, &template_len);
if (err)