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sm: Support generation of card-based ECDSA CSR.

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* sm/call-agent.c (gpgsm_scd_pksign): Identify type of signing key
and format resulting S-expression accordingly.
* sm/misc.c (transform_sigval): Support ECDSA signatures.
--

Current GpgSM implementation assumes card-based keys are RSA keys.
This patch introduces support for ECDSA keys.

By itself this patch is not sufficient, we also need support
from libksba.

GnuPG-bug-id: 4092
Signed-off-by: Damien Goutte-Gattat <dgouttegattat@incenp.org>
This commit is contained in:
Damien Goutte-Gattat via Gnupg-devel 2018-11-16 01:27:37 +00:00 committed by NIIBE Yutaka
parent b89f1790e0
commit 74e9b579ca
2 changed files with 98 additions and 34 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

57
sm/call-agent.c
View File

@ -334,7 +334,7 @@ gpgsm_scd_pksign (ctrl_t ctrl, const char *keyid, const char *desc,
unsigned char *digest, size_t digestlen, int digestalgo, unsigned char *digest, size_t digestlen, int digestalgo,
unsigned char **r_buf, size_t *r_buflen ) unsigned char **r_buf, size_t *r_buflen )
{ {
int rc, i; int rc, i, pkalgo;
char *p, line[ASSUAN_LINELENGTH]; char *p, line[ASSUAN_LINELENGTH];
membuf_t data; membuf_t data;
size_t len; size_t len;
@ -342,6 +342,7 @@ gpgsm_scd_pksign (ctrl_t ctrl, const char *keyid, const char *desc,
unsigned char *sigbuf; unsigned char *sigbuf;
size_t sigbuflen; size_t sigbuflen;
struct default_inq_parm_s inq_parm; struct default_inq_parm_s inq_parm;
gcry_sexp_t sig;
(void)desc; (void)desc;
@ -366,6 +367,23 @@ gpgsm_scd_pksign (ctrl_t ctrl, const char *keyid, const char *desc,
if (digestlen*2 + 50 > DIM(line)) if (digestlen*2 + 50 > DIM(line))
return gpg_error (GPG_ERR_GENERAL); return gpg_error (GPG_ERR_GENERAL);
/* Get the key type from the scdaemon. */
snprintf (line, DIM(line), "SCD READKEY %s", keyid);
init_membuf (&data, 1024);
rc = assuan_transact (agent_ctx, line,
put_membuf_cb, &data, NULL, NULL, NULL, NULL);
if (rc)
{
xfree (get_membuf (&data, &len));
return rc;
}
p = get_membuf (&data, &len);
pkalgo = get_pk_algo_from_canon_sexp (p, len);
xfree (p);
if (!pkalgo)
return gpg_error (GPG_ERR_WRONG_PUBKEY_ALGO);
p = stpcpy (line, "SCD SETDATA " ); p = stpcpy (line, "SCD SETDATA " );
for (i=0; i < digestlen ; i++, p += 2 ) for (i=0; i < digestlen ; i++, p += 2 )
sprintf (p, "%02X", digest[i]); sprintf (p, "%02X", digest[i]);
@ -386,24 +404,31 @@ gpgsm_scd_pksign (ctrl_t ctrl, const char *keyid, const char *desc,
} }
sigbuf = get_membuf (&data, &sigbuflen); sigbuf = get_membuf (&data, &sigbuflen);
/* Create an S-expression from it which is formatted like this: switch(pkalgo)
"(7:sig-val(3:rsa(1:sSIGBUFLEN:SIGBUF)))" Fixme: If a card ever
creates non-RSA keys we need to change things. */
*r_buflen = 21 + 11 + sigbuflen + 4;
p = xtrymalloc (*r_buflen);
*r_buf = (unsigned char*)p;
if (!p)
{ {
xfree (sigbuf); case GCRY_PK_RSA:
return 0; rc = gcry_sexp_build (&sig, NULL, "(sig-val(rsa(s%b)))",
sigbuflen, sigbuf);
break;
case GCRY_PK_ECC:
rc = gcry_sexp_build (&sig, NULL, "(sig-val(ecdsa(r%b)(s%b)))",
sigbuflen/2, sigbuf,
sigbuflen/2, sigbuf + sigbuflen/2);
break;
default:
rc = gpg_error (GPG_ERR_WRONG_PUBKEY_ALGO);
break;
} }
p = stpcpy (p, "(7:sig-val(3:rsa(1:s" );
sprintf (p, "%u:", (unsigned int)sigbuflen);
p += strlen (p);
memcpy (p, sigbuf, sigbuflen);
p += sigbuflen;
strcpy (p, ")))");
xfree (sigbuf); xfree (sigbuf);
if (rc)
return rc;
rc = make_canon_sexp (sig, r_buf, r_buflen);
gcry_sexp_release (sig);
if (rc)
return rc;
assert (gcry_sexp_canon_len (*r_buf, *r_buflen, NULL, NULL)); assert (gcry_sexp_canon_len (*r_buf, *r_buflen, NULL, NULL));
return 0; return 0;

75
sm/misc.c
View File

@ -109,13 +109,16 @@ transform_sigval (const unsigned char *sigval, size_t sigvallen, int mdalgo,
gpg_error_t err; gpg_error_t err;
const unsigned char *buf, *tok; const unsigned char *buf, *tok;
size_t buflen, toklen; size_t buflen, toklen;
int depth, last_depth1, last_depth2; int depth, last_depth1, last_depth2, pkalgo;
int is_pubkey = 0; int is_pubkey = 0;
const unsigned char *rsa_s = NULL; const unsigned char *rsa_s, *ecc_r, *ecc_s;
size_t rsa_s_len = 0; size_t rsa_s_len, ecc_r_len, ecc_s_len;
const char *oid; const char *oid;
gcry_sexp_t sexp; gcry_sexp_t sexp;
rsa_s = ecc_r = ecc_s = NULL;
rsa_s_len = ecc_r_len = ecc_s_len = 0;
*r_newsigval = NULL; *r_newsigval = NULL;
if (r_newsigvallen) if (r_newsigvallen)
*r_newsigvallen = 0; *r_newsigvallen = 0;
@ -137,7 +140,13 @@ transform_sigval (const unsigned char *sigval, size_t sigvallen, int mdalgo,
return err; return err;
if ((err = parse_sexp (&buf, &buflen, &depth, &tok, &toklen))) if ((err = parse_sexp (&buf, &buflen, &depth, &tok, &toklen)))
return err; return err;
if (!tok || toklen != 3 || memcmp ("rsa", tok, toklen)) if (!tok)
return gpg_error (GPG_ERR_WRONG_PUBKEY_ALGO);
if (toklen == 3 && !memcmp ("rsa", tok, 3))
pkalgo = GCRY_PK_RSA;
else if (toklen == 5 && !memcmp ("ecdsa", tok, 5))
pkalgo = GCRY_PK_ECC;
else
return gpg_error (GPG_ERR_WRONG_PUBKEY_ALGO); return gpg_error (GPG_ERR_WRONG_PUBKEY_ALGO);
last_depth1 = depth; last_depth1 = depth;
@ -150,16 +159,27 @@ transform_sigval (const unsigned char *sigval, size_t sigvallen, int mdalgo,
return err; return err;
if (tok && toklen == 1) if (tok && toklen == 1)
{ {
const unsigned char **mpi; const unsigned char **mpi = NULL;
size_t *mpi_len; size_t *mpi_len = NULL;
switch (*tok) switch (*tok)
{ {
case 's': mpi = &rsa_s; mpi_len = &rsa_s_len; break; case 's':
if (pkalgo == GCRY_PK_RSA)
{
mpi = &rsa_s;
mpi_len = &rsa_s_len;
}
else if (pkalgo == GCRY_PK_ECC)
{
mpi = &ecc_s;
mpi_len = &ecc_s_len;
}
break;
case 'r': mpi = &ecc_r; mpi_len = &ecc_r_len; break;
default: mpi = NULL; mpi_len = NULL; break; default: mpi = NULL; mpi_len = NULL; break;
} }
if (mpi && *mpi)
return gpg_error (GPG_ERR_DUP_VALUE);
if ((err = parse_sexp (&buf, &buflen, &depth, &tok, &toklen))) if ((err = parse_sexp (&buf, &buflen, &depth, &tok, &toklen)))
return err; return err;
@ -182,33 +202,52 @@ transform_sigval (const unsigned char *sigval, size_t sigvallen, int mdalgo,
return err; return err;
/* Map the hash algorithm to an OID. */ /* Map the hash algorithm to an OID. */
switch (mdalgo) switch (mdalgo | (pkalgo << 8))
{ {
case GCRY_MD_SHA1: case GCRY_MD_SHA1 | (GCRY_PK_RSA << 8):
oid = "1.2.840.113549.1.1.5"; /* sha1WithRSAEncryption */ oid = "1.2.840.113549.1.1.5"; /* sha1WithRSAEncryption */
break; break;
case GCRY_MD_SHA256: case GCRY_MD_SHA256 | (GCRY_PK_RSA << 8):
oid = "1.2.840.113549.1.1.11"; /* sha256WithRSAEncryption */ oid = "1.2.840.113549.1.1.11"; /* sha256WithRSAEncryption */
break; break;
case GCRY_MD_SHA384: case GCRY_MD_SHA384 | (GCRY_PK_RSA << 8):
oid = "1.2.840.113549.1.1.12"; /* sha384WithRSAEncryption */ oid = "1.2.840.113549.1.1.12"; /* sha384WithRSAEncryption */
break; break;
case GCRY_MD_SHA512: case GCRY_MD_SHA512 | (GCRY_PK_RSA << 8):
oid = "1.2.840.113549.1.1.13"; /* sha512WithRSAEncryption */ oid = "1.2.840.113549.1.1.13"; /* sha512WithRSAEncryption */
break; break;
case GCRY_MD_SHA224 | (GCRY_PK_ECC << 8):
oid = "1.2.840.10045.4.3.1"; /* ecdsa-with-sha224 */
break;
case GCRY_MD_SHA256 | (GCRY_PK_ECC << 8):
oid = "1.2.840.10045.4.3.2"; /* ecdsa-with-sha256 */
break;
case GCRY_MD_SHA384 | (GCRY_PK_ECC << 8):
oid = "1.2.840.10045.4.3.3"; /* ecdsa-with-sha384 */
break;
case GCRY_MD_SHA512 | (GCRY_PK_ECC << 8):
oid = "1.2.840.10045.4.3.4"; /* ecdsa-with-sha512 */
break;
default: default:
return gpg_error (GPG_ERR_DIGEST_ALGO); return gpg_error (GPG_ERR_DIGEST_ALGO);
} }
if (rsa_s && !is_pubkey) if (is_pubkey)
err = gcry_sexp_build (&sexp, NULL, "(sig-val(%s(s%b)))",
oid, (int)rsa_s_len, rsa_s);
else
err = gcry_sexp_build (&sexp, NULL, "(sig-val(%s))", oid); err = gcry_sexp_build (&sexp, NULL, "(sig-val(%s))", oid);
else if (pkalgo == GCRY_PK_RSA)
err = gcry_sexp_build (&sexp, NULL, "(sig-val(%s(s%b)))", oid,
(int)rsa_s_len, rsa_s);
else if (pkalgo == GCRY_PK_ECC)
err = gcry_sexp_build (&sexp, NULL, "(sig-val(%s(r%b)(s%b)))", oid,
(int)ecc_r_len, ecc_r, (int)ecc_s_len, ecc_s);
if (err) if (err)
return err; return err;
err = make_canon_sexp (sexp, r_newsigval, r_newsigvallen); err = make_canon_sexp (sexp, r_newsigval, r_newsigvallen);