diff options
Diffstat (limited to 'agent/pksign.c')
| -rw-r--r-- | agent/pksign.c | 139 |
1 files changed, 136 insertions, 3 deletions
diff --git a/agent/pksign.c b/agent/pksign.c index 69093a07c..f597c8aa2 100644 --- a/agent/pksign.c +++ b/agent/pksign.c @@ -24,16 +24,149 @@ #include <stdlib.h> #include <string.h> #include <ctype.h> +#include <assert.h> #include <unistd.h> #include "agent.h" -/* SIGN whatever information we have accumulated in CTRL and write it back to - OUTFP. */ +static int +do_encode_md (const unsigned char *digest, size_t digestlen, int algo, + unsigned int nbits, GCRY_MPI *r_val) +{ + int nframe = (nbits+7) / 8; + byte *frame; + int i, n; + byte asn[100]; + size_t asnlen; + + asnlen = DIM(asn); + if (gcry_md_algo_info (algo, GCRYCTL_GET_ASNOID, asn, &asnlen)) + { + log_error ("No object identifier for algo %d\n", algo); + return GNUPG_Internal_Error; + } + + if (digestlen + asnlen + 4 > nframe ) + { + log_error ("can't encode a %d bit MD into a %d bits frame\n", + (int)(digestlen*8), (int)nbits); + return GNUPG_Internal_Error; + } + + /* We encode the MD in this way: + * + * 0 A PAD(n bytes) 0 ASN(asnlen bytes) MD(len bytes) + * + * PAD consists of FF bytes. + */ + frame = xtrymalloc (nframe); + if (!frame) + return GNUPG_Out_Of_Core; + n = 0; + frame[n++] = 0; + frame[n++] = 1; /* block type */ + i = nframe - digestlen - asnlen -3 ; + assert ( i > 1 ); + memset ( frame+n, 0xff, i ); n += i; + frame[n++] = 0; + memcpy ( frame+n, asn, asnlen ); n += asnlen; + memcpy ( frame+n, digest, digestlen ); n += digestlen; + assert ( n == nframe ); + if (DBG_CRYPTO) + { + int j; + log_debug ("encoded hash:"); + for (j=0; j < nframe; j++) + log_printf (" %02X", frame[j]); + log_printf ("\n"); + } + + gcry_mpi_scan (r_val, GCRYMPI_FMT_USG, frame, &nframe); + xfree (frame); + return 0; +} + + +/* SIGN whatever information we have accumulated in CTRL and write it + back to OUTFP. */ int agent_pksign (CTRL ctrl, FILE *outfp) { + /* our sample key */ + const char n[] = "#8732A669BB7C5057AD070EFA54E035C86DF474F7A7EBE2435" + "3DADEB86FFE74C32AEEF9E5C6BD7584CB572520167B3E8C89A1FA75C74FF9E938" + "2710F3B270B638EB96E7486491D81C53CA8A50B4E840B1C7458A4A1E52EC18D681" + "8A2805C9165827F77EF90D55014E4B2AF9386AE8F6462F46A547CB593ABD509311" + "4D3D16375F#"; + const char e[] = "#11#"; + const char d[] = "#07F3EBABDDDA22D7FB1E8869140D30571586D9B4370DE02213F" + "DD0DDAC3C24FC6BEFF0950BB0CAAD755F7AA788DA12BCF90987341AC8781CC7115" + "B59A115B05D9D99B3D7AF77854DC2EE6A36154512CC0EAD832601038A88E837112" + "AB2A39FD9FBE05E30D6FFA6F43D71C59F423CA43BC91C254A8C89673AB61F326B0" + "762FBC9#"; + const char p[] = "#B2ABAD4328E66303E206C53CFBED17F18F712B1C47C966EE13DD" + "AA9AD3616A610ADF513F8376FA48BAE12FED64CECC1E73091A77B45119AF0FC1286A" + "85BD9BBD#"; + const char q[] = "#C1B648B294BB9AEE7FEEB77C4F64E9333E4EA9A7C54D521356FB" + "BBB7558A0E7D6331EC7B42E3F0CD7BBBA9B7A013422F615F10DCC1E8462828BF8FC7" + "39C5E34B#"; + const char u[] = "#A9B5EFF9C80A4A356B9A95EB63E381B262071E5CE9C1F32FF03" + "83AD8289BED8BC690555E54411FA2FDB9B49638A21B2046C325F5633B4B1ECABEBFD" + "1B3519072#"; + + GCRY_SEXP s_skey, s_hash, s_sig; + GCRY_MPI frame; + int rc; + char *buf; + size_t len; - return -1; + /* create a secret key as an sexp */ + log_debug ("Using HARDWIRED secret key\n"); + asprintf (&buf, "(private-key(oid.1.2.840.113549.1.1.1" + "(n %s)(e %s)(d %s)(p %s)(q %s)(u %s)))", + n, e, d, p, q, u); + /* asprintf does not use our allocation fucntions, so we can't + use our free */ + rc = gcry_sexp_sscan (&s_skey, NULL, buf, strlen(buf)); + free (buf); + if (rc) + { + log_error ("failed to build S-Exp: %s\n", gcry_strerror (rc)); + return map_gcry_err (rc); + } + + /* put the hash into a sexp */ + rc = do_encode_md (ctrl->digest.value, + ctrl->digest.valuelen, + ctrl->digest.algo, + gcry_pk_get_nbits (s_skey), + &frame); + if (rc) + { + /* fixme: clean up some things */ + return rc; + } + if ( gcry_sexp_build (&s_hash, NULL, "%m", frame) ) + BUG (); + + + /* sign */ + rc = gcry_pk_sign (&s_sig, s_hash, s_skey); + if (rc) + { + log_error ("signing failed: %s\n", gcry_strerror (rc)); + return map_gcry_err (rc); + } + + len = gcry_sexp_sprint (s_sig, GCRYSEXP_FMT_CANON, NULL, 0); + assert (len); + buf = xmalloc (len); + len = gcry_sexp_sprint (s_sig, GCRYSEXP_FMT_CANON, buf, len); + assert (len); + + fwrite (buf, 1, strlen(buf), outfp); + return 0; } + + |