X-Git-Url: https://git.distorted.org.uk/u/mdw/catacomb/blobdiff_plain/ba6e6b64033b1f9de49feccb5c9cd438354481f7..0f00dc4c8eb47e67bc0f148c2dd109f73a451e0a:/key/key-binary.c?ds=sidebyside diff --git a/key/key-binary.c b/key/key-binary.c new file mode 100644 index 0000000..046819a --- /dev/null +++ b/key/key-binary.c @@ -0,0 +1,314 @@ +/* -*-c-*- + * + * Key binary encoding + * + * (c) 1999 Straylight/Edgeware + */ + +/*----- Licensing notice --------------------------------------------------* + * + * This file is part of Catacomb. + * + * Catacomb is free software; you can redistribute it and/or modify + * it under the terms of the GNU Library General Public License as + * published by the Free Software Foundation; either version 2 of the + * License, or (at your option) any later version. + * + * Catacomb is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU Library General Public License for more details. + * + * You should have received a copy of the GNU Library General Public + * License along with Catacomb; if not, write to the Free + * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, + * MA 02111-1307, USA. + */ + +/*----- Header files ------------------------------------------------------*/ + +#include +#include + +#include +#include +#include +#include + +#include "key-data.h" +#include "mp.h" +#include "mptext.h" + +/*----- Main code ---------------------------------------------------------*/ + +/* --- @key_decode@ --- * + * + * Arguments: @const void *p@ = pointer to buffer to read + * @size_t sz@ = size of the buffer + * + * Returns: The newly-read key data, or null if it failed. + * + * Use: Decodes a binary representation of a key. + */ + +key_data *key_decode(const void *p, size_t sz) +{ + const octet *q = p; + size_t psz; + key_data *kd; + unsigned e; + + /* --- Parse the header information --- * + * + * Make sure the size matches external reality. Security holes have been + * known to creep in without this sort of check. (No, this isn't an after- + * the-fact patch-up.) + */ + + e = LOAD16(q); + psz = LOAD16(q + 2); + if (psz + 4 > sz) + return (0); + + /* --- Now decide what to do --- */ + + switch (e & KF_ENCMASK) { + + /* --- Plain binary data --- */ + + case KENC_BINARY: + case KENC_ENCRYPT: + kd = key_newbinary(e, q + 4, psz); + break; + + /* --- Multiprecision integer data --- */ + + case KENC_MP: + kd = key_newmp(e, mp_loadb(e & KF_BURN ? MP_NEWSEC : MP_NEW, + q + 4, psz)); + break; + + /* --- String data --- */ + + case KENC_STRING: + kd = key_newraw(e); + kd->u.p = xmalloc(sz + 1); + memcpy(kd->u.p, q + 4, sz); + kd->u.p[sz] = 0; + break; + + /* --- Elliptic curve point data --- */ + + case KENC_EC: { + size_t xsz, ysz; + kd = key_newraw(e); + EC_CREATE(&kd->u.e); + if (!sz) break; + if (sz < 2) return (0); + xsz = LOAD16(q + 4); + if (sz < xsz + 4) return (0); + ysz = LOAD16(q + 6 + xsz); + if (sz < xsz + ysz + 4) return (0); + kd->u.e.x = mp_loadb(MP_NEW, q + 6, xsz); + kd->u.e.y = mp_loadb(MP_NEW, q + 8 + xsz, ysz); + } break; + + /* --- Structured key data --- */ + + case KENC_STRUCT: { + dstr d = DSTR_INIT; + key_data *nkd; + + if ((e & ~KF_ENCMASK) || (psz & 3)) + return (0); + q += 4; + kd = key_newstruct(); + + while (psz) { + + /* --- Read the tag string --- */ + + DRESET(&d); + sz = LOAD8(q); + if (sz >= psz) + goto fail; + DPUTM(&d, q + 1, sz); + DPUTZ(&d); + sz = (sz + 4) & ~3; + q += sz; psz -= sz; + + /* --- Read the encoding and size --- */ + + sz = (LOAD16(q + 2) + 7) & ~3; + if (sz > psz) + goto fail; + + /* --- Create a table node and fill it in --- */ + + if ((nkd = key_decode(q, sz)) == 0) + goto fail; + key_structsteal(kd, d.buf, nkd); + psz -= sz; + q += sz; + } + dstr_destroy(&d); + break; + + /* --- Tidy up after a failure --- */ + + fail: + dstr_destroy(&d); + key_drop(kd); + return (0); + } break; + + /* --- Everything else --- */ + + default: + return (0); + } + + /* --- OK, that was good --- */ + + kd->e = e; + return (kd); +} + +/* --- @key_encode@ --- * + * + * Arguments: @key_data *k@ = pointer to key data block + * @dstr *d@ = pointer to destination string + * @const key_filter *kf@ = pointer to key selection block + * + * Returns: Nonzero if an item was actually written. + * + * Use: Encodes a key block as binary data. + */ + +static int ksbyname(const void *a, const void *b) { + key_struct *const *x = a, *const *y = b; + return (strcmp(SYM_NAME(*x), SYM_NAME(*y))); +} + +int key_encode(key_data *k, dstr *d, const key_filter *kf) +{ + int rc = 0; + if (!KEY_MATCH(k, kf)) + return (0); + switch (k->e & KF_ENCMASK) { + case KENC_BINARY: + case KENC_ENCRYPT: { + char *p; + + DENSURE(d, (k->u.k.sz + 7) & ~3); + p = d->buf + d->len; + STORE16(p, k->e); + STORE16(p + 2, k->u.k.sz); + d->len += 4; + DPUTM(d, k->u.k.k, k->u.k.sz); + rc = 1; + } break; + + case KENC_MP: { + char *p; + size_t sz = mp_octets(k->u.m); + + DENSURE(d, (sz + 7) & ~3); + p = d->buf + d->len; + STORE16(p, k->e); + STORE16(p + 2, sz); + mp_storeb(k->u.m, p + 4, sz); + d->len += sz + 4; + rc = 1; + } break; + + case KENC_STRING: { + char *p; + size_t sz = strlen(k->u.p); + + DENSURE(d, (sz + 7) & ~3); + p = d->buf + d->len; + STORE16(p, k->e); + STORE16(p + 2, sz); + memcpy(p + 4, k->u.p, sz); + d->len += sz + 4; + rc = 1; + } break; + + case KENC_EC: { + char *p; + size_t xsz = 0, ysz = 0; + size_t sz; + + if (EC_ATINF(&k->u.e)) + sz = 0; + else { + xsz = mp_octets(k->u.e.x); + ysz = mp_octets(k->u.e.y); + sz = xsz + ysz + 4; + } + DENSURE(d, (sz + 7) & ~3); + p = d->buf + d->len; + STORE16(p, k->e); + STORE16(p + 2, sz); + if (!EC_ATINF(&k->u.e)) { + STORE16(p + 4, xsz); + mp_storeb(k->u.e.x, p + 6, xsz); + STORE16(p + 6 + xsz, ysz); + mp_storeb(k->u.e.y, p + 8 + xsz, ysz); + } + d->len += sz + 4; + rc = 1; + } break; + + case KENC_STRUCT: { + size_t n; + char *p; + key_struct *ks, **ksv; + size_t nks, j; + sym_iter i; + + n = d->len; + DENSURE(d, 4); + p = d->buf + n; + STORE16(p, k->e & KF_ENCMASK); + d->len += 4; + + for (nks = 0, sym_mkiter(&i, &k->u.s); + (ks = sym_next(&i)) != 0; + nks++); + if (nks) { + ksv = xmalloc(nks * sizeof(*ksv)); + for (j = 0, sym_mkiter(&i, &k->u.s); (ks = sym_next(&i)) != 0; j++) + ksv[j] = ks; + qsort(ksv, nks, sizeof(*ksv), ksbyname); + for (j = 0; j < nks; j++) { + size_t o = d->len; + ks = ksv[j]; + DENSURE(d, 1); + *(octet *)(d->buf + d->len++) = strlen(SYM_NAME(ks)); + DPUTS(d, SYM_NAME(ks)); + while (d->len & 3) + DPUTC(d, 0); + if (key_encode(ks->k, d, kf)) + rc = 1; + else + d->len = o; + } + xfree(ksv); + } + if (!rc) + d->len = n; + else { + p = d->buf + n + 2; + n = d->len - n - 4; + STORE16(p, n); + } + } break; + } + while (d->len & 3) + DPUTC(d, 0); + return (rc); +} + +/*----- That's all, folks -------------------------------------------------*/