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New helper function factored out of ../scd and equipped with test code.

This commit is contained in:
Werner Koch 2009-05-07 15:01:47 +00:00
parent 6adb13b079
commit 03aae15a56
4 changed files with 288 additions and 0 deletions
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10
common/ChangeLog
View File

@ -1,3 +1,13 @@
2009-05-07 Werner Koch <wk@g10code.com>
* sexputil.c (get_rsa_pk_from_canon_sexp): New.
* t-sexputil.c (test_make_canon_sexp_from_rsa_pk): Extend the test.
2009-04-28 Werner Koch <wk@g10code.com>
* sexputil.c (make_canon_sexp_from_rsa_pk): New.
* t-sexputil.c (test_make_canon_sexp_from_rsa_pk): New.
2009-04-01 Werner Koch <wk@g10code.com>
* iobuf.c: Port David's changes from 1.4:

161
common/sexputil.c
View File

@ -32,6 +32,7 @@
#endif
#include "util.h"
#include "tlv.h"
#include "sexp-parse.h"
@ -225,3 +226,163 @@ hash_algo_from_sigval (const unsigned char *sigval)
return gcry_md_map_name (buffer);
}
/* Create a public key S-expression for an RSA public key from the
modulus M with length MLEN and the public exponent E with length
ELEN. Returns a newly allocated buffer of NULL in case of a memory
allocation problem. If R_LEN is not NULL, the length of the
canonical S-expression is stored there. */
unsigned char *
make_canon_sexp_from_rsa_pk (const void *m_arg, size_t mlen,
const void *e_arg, size_t elen,
size_t *r_len)
{
const unsigned char *m = m_arg;
const unsigned char *e = e_arg;
int m_extra = 0;
int e_extra = 0;
char mlen_str[35];
char elen_str[35];
unsigned char *keybuf, *p;
const char const part1[] = "(10:public-key(3:rsa(1:n";
const char const part2[] = ")(1:e";
const char const part3[] = ")))";
/* Remove leading zeroes. */
for (; mlen && !*m; mlen--, m++)
;
for (; elen && !*e; elen--, e++)
;
/* Insert a leading zero if the number would be zero or interpreted
as negative. */
if (!mlen || (m[0] & 0x80))
m_extra = 1;
if (!elen || (e[0] & 0x80))
e_extra = 1;
/* Build the S-expression. */
snprintf (mlen_str, sizeof mlen_str, "%u:", (unsigned int)mlen+m_extra);
snprintf (elen_str, sizeof elen_str, "%u:", (unsigned int)elen+e_extra);
keybuf = xtrymalloc (strlen (part1) + strlen (mlen_str) + mlen + m_extra
+ strlen (part2) + strlen (elen_str) + elen + e_extra
+ strlen (part3) + 1);
if (!keybuf)
return NULL;
p = stpcpy (keybuf, part1);
p = stpcpy (p, mlen_str);
if (m_extra)
*p++ = 0;
memcpy (p, m, mlen);
p += mlen;
p = stpcpy (p, part2);
p = stpcpy (p, elen_str);
if (e_extra)
*p++ = 0;
memcpy (p, e, elen);
p += elen;
p = stpcpy (p, part3);
if (r_len)
*r_len = p - keybuf;
return keybuf;
}
/* Return the so called "keygrip" which is the SHA-1 hash of the
public key parameters expressed in a way depended on the algorithm.
KEY is expected to be an canonical encoded S-expression with a
public or private key. KEYLEN is the length of that buffer.
GRIP must be at least 20 bytes long. On success 0 is returned, on
error an error code. */
gpg_error_t
get_rsa_pk_from_canon_sexp (const unsigned char *keydata, size_t keydatalen,
unsigned char const **r_n, size_t *r_nlen,
unsigned char const **r_e, size_t *r_elen)
{
gpg_error_t err;
const unsigned char *buf, *tok;
size_t buflen, toklen;
int depth, last_depth1, last_depth2;
const unsigned char *rsa_n = NULL;
const unsigned char *rsa_e = NULL;
size_t rsa_n_len, rsa_e_len;
*r_n = NULL;
*r_nlen = 0;
*r_e = NULL;
*r_elen = 0;
buf = keydata;
buflen = keydatalen;
depth = 0;
if ((err = parse_sexp (&buf, &buflen, &depth, &tok, &toklen)))
return err;
if ((err = parse_sexp (&buf, &buflen, &depth, &tok, &toklen)))
return err;
if (!tok || toklen != 10 || memcmp ("public-key", tok, toklen))
return gpg_error (GPG_ERR_BAD_PUBKEY);
if ((err = parse_sexp (&buf, &buflen, &depth, &tok, &toklen)))
return err;
if ((err = parse_sexp (&buf, &buflen, &depth, &tok, &toklen)))
return err;
if (!tok || toklen != 3 || memcmp ("rsa", tok, toklen))
return gpg_error (GPG_ERR_WRONG_PUBKEY_ALGO);
last_depth1 = depth;
while (!(err = parse_sexp (&buf, &buflen, &depth, &tok, &toklen))
&& depth && depth >= last_depth1)
{
if (tok)
return gpg_error (GPG_ERR_UNKNOWN_SEXP);
if ((err = parse_sexp (&buf, &buflen, &depth, &tok, &toklen)))
return err;
if (tok && toklen == 1)
{
const unsigned char **mpi;
size_t *mpi_len;
switch (*tok)
{
case 'n': mpi = &rsa_n; mpi_len = &rsa_n_len; break;
case 'e': mpi = &rsa_e; mpi_len = &rsa_e_len; 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)))
return err;
if (tok && mpi)
{
/* Strip off leading zero bytes and save. */
for (;toklen && !*tok; toklen--, tok++)
;
*mpi = tok;
*mpi_len = toklen;
}
}
/* Skip to the end of the list. */
last_depth2 = depth;
while (!(err = parse_sexp (&buf, &buflen, &depth, &tok, &toklen))
&& depth && depth >= last_depth2)
;
if (err)
return err;
}
if (!rsa_n || !rsa_n_len || !rsa_e || !rsa_e_len)
return gpg_error (GPG_ERR_BAD_PUBKEY);
*r_n = rsa_n;
*r_nlen = rsa_n_len;
*r_e = rsa_e;
*r_elen = rsa_e_len;
return 0;
}

108
common/t-sexputil.c
View File

@ -69,6 +69,113 @@ test_hash_algo_from_sigval (void)
}
static void
test_make_canon_sexp_from_rsa_pk (void)
{
struct {
unsigned char *m;
size_t mlen;
unsigned char *e;
size_t elen;
unsigned char *result;
size_t resultlen;
gpg_err_code_t reverr; /* Expected error from the reverse fucntion. */
} tests[] = {
{
"\x82\xB4\x12\x48\x08\x48\xC0\x76\xAA\x8E\xF1\xF8\x7F\x5E\x9B\x89"
"\xA9\x62\x92\xA2\x16\x1B\xF5\x9F\xE1\x41\xF3\xF0\x42\xB5\x5C\x46"
"\xB8\x83\x9F\x39\x97\x73\xFF\xC5\xB2\xF4\x59\x5F\xBA\xC7\x0E\x03"
"\x9D\x27\xC0\x86\x37\x31\x46\xE0\xA1\xFE\xA1\x41\xD4\xE3\xE9\xB3"
"\x9B\xD5\x84\x65\xA5\x37\x35\x34\x07\x58\xB6\xBA\x21\xCA\x21\x72"
"\x4C\xF3\xFC\x91\x47\xD1\x3C\x1D\xA5\x9C\x38\x4D\x58\x39\x92\x16"
"\xB1\xE5\x43\xFE\xB5\x46\x4B\x43\xD1\x47\xB0\xE8\x2A\xDB\xF8\x34"
"\xB0\x5A\x22\x3D\x14\xBB\xEA\x63\x65\xA7\xF1\xF2\xF8\x97\x74\xA7",
128,
"\x40\x00\x00\x81",
4,
"\x28\x31\x30\x3a\x70\x75\x62\x6c\x69\x63\x2d\x6b\x65\x79\x28\x33"
"\x3a\x72\x73\x61\x28\x31\x3a\x6e\x31\x32\x39\x3a\x00\x82\xb4\x12"
"\x48\x08\x48\xc0\x76\xaa\x8e\xf1\xf8\x7f\x5e\x9b\x89\xa9\x62\x92"
"\xa2\x16\x1b\xf5\x9f\xe1\x41\xf3\xf0\x42\xb5\x5c\x46\xb8\x83\x9f"
"\x39\x97\x73\xff\xc5\xb2\xf4\x59\x5f\xba\xc7\x0e\x03\x9d\x27\xc0"
"\x86\x37\x31\x46\xe0\xa1\xfe\xa1\x41\xd4\xe3\xe9\xb3\x9b\xd5\x84"
"\x65\xa5\x37\x35\x34\x07\x58\xb6\xba\x21\xca\x21\x72\x4c\xf3\xfc"
"\x91\x47\xd1\x3c\x1d\xa5\x9c\x38\x4d\x58\x39\x92\x16\xb1\xe5\x43"
"\xfe\xb5\x46\x4b\x43\xd1\x47\xb0\xe8\x2a\xdb\xf8\x34\xb0\x5a\x22"
"\x3d\x14\xbb\xea\x63\x65\xa7\xf1\xf2\xf8\x97\x74\xa7\x29\x28\x31"
"\x3a\x65\x34\x3a\x40\x00\x00\x81\x29\x29\x29",
171
},
{
"\x63\xB4\x12\x48\x08\x48\xC0\x76\xAA\x8E\xF1\xF8\x7F\x5E\x9B\x89",
16,
"\x03",
1,
"\x28\x31\x30\x3a\x70\x75\x62\x6c\x69\x63\x2d\x6b\x65\x79\x28\x33"
"\x3a\x72\x73\x61\x28\x31\x3a\x6e\x31\x36\x3a\x63\xb4\x12\x48\x08"
"\x48\xc0\x76\xaa\x8e\xf1\xf8\x7f\x5e\x9b\x89\x29\x28\x31\x3a\x65"
"\x31\x3a\x03\x29\x29\x29",
54,
},
{
"",
0,
"",
0,
"\x28\x31\x30\x3a\x70\x75\x62\x6c\x69\x63\x2d\x6b\x65\x79\x28\x33"
"\x3a\x72\x73\x61\x28\x31\x3a\x6e\x31\x3a\x00\x29\x28\x31\x3a\x65"
"\x31\x3a\x00\x29\x29\x29",
38,
GPG_ERR_BAD_PUBKEY
},
{
NULL
}
};
int idx;
gpg_error_t err;
unsigned char *sexp;
size_t length;
const unsigned char *rsa_n, *rsa_e;
size_t rsa_n_len, rsa_e_len;
for (idx=0; tests[idx].m; idx++)
{
sexp = make_canon_sexp_from_rsa_pk (tests[idx].m, tests[idx].mlen,
tests[idx].e, tests[idx].elen,
&length);
if (!sexp)
{
fprintf (stderr, "%s:%d: out of core\n", __FILE__, __LINE__);
exit (1);
}
if (length != tests[idx].resultlen)
fail (idx);
if (memcmp (sexp, tests[idx].result, tests[idx].resultlen))
fail (idx);
/* Test the reverse function. */
err = get_rsa_pk_from_canon_sexp (sexp, length,
&rsa_n, &rsa_n_len,
&rsa_e, &rsa_e_len);
if (gpg_err_code (err) != tests[idx].reverr)
fail (idx);
if (!err)
{
if (tests[idx].mlen != rsa_n_len)
fail (idx);
if (memcmp (tests[idx].m, rsa_n, rsa_n_len))
fail (idx);
if (tests[idx].elen != rsa_e_len)
fail (idx);
if (memcmp (tests[idx].e, rsa_e, rsa_e_len))
fail (idx);
}
xfree (sexp);
}
}
int
@ -78,6 +185,7 @@ main (int argc, char **argv)
(void)argv;
test_hash_algo_from_sigval ();
test_make_canon_sexp_from_rsa_pk ();
return 0;
}

9
common/util.h
View File

@ -192,6 +192,15 @@ int cmp_simple_canon_sexp (const unsigned char *a, const unsigned char *b);
unsigned char *make_simple_sexp_from_hexstr (const char *line,
size_t *nscanned);
int hash_algo_from_sigval (const unsigned char *sigval);
unsigned char *make_canon_sexp_from_rsa_pk (const void *m, size_t mlen,
const void *e, size_t elen,
size_t *r_len);
gpg_error_t get_rsa_pk_from_canon_sexp (const unsigned char *keydata,
size_t keydatalen,
unsigned char const **r_n,
size_t *r_nlen,
unsigned char const **r_e,
size_t *r_elen);
/*-- convert.c --*/
int hex2bin (const char *string, void *buffer, size_t length);