-/* This file is part of secnet, and is distributed under the terms of
- the GNU General Public License version 2 or later.
+/*
+ * rsa.c: implementation of RSA with PKCS#1 padding
+ */
+/*
+ * This file is Free Software. It was originally written for secnet.
+ *
+ * Copyright 1995-2003 Stephen Early
+ * Copyright 2002-2014 Ian Jackson
+ * Copyright 2001 Simon Tatham
+ * Copyright 2013 Mark Wooding
+ *
+ * You may redistribute secnet as a whole and/or modify it under the
+ * terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 3, or (at your option) any
+ * later version.
+ *
+ * You may redistribute this file and/or modify it under the terms of
+ * the GNU General Public License as published by the Free Software
+ * Foundation; either version 2, or (at your option) any later
+ * version.
+ *
+ * This software 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this software; if not, see
+ * https://www.gnu.org/licenses/gpl.html.
+ */
- Copyright (C) 1995-2002 Stephen Early
- Copyright (C) 2001 Simon Tatham
- Copyright (C) 2002 Ian Jackson
- */
#include <stdio.h>
#include <string.h>
};
/* Sign data. NB data must be smaller than modulus */
+#define RSA_MAX_MODBYTES 2048
+/* The largest modulus I've seen is 15360 bits, which works out at 1920
+ * bytes. Using keys this big is quite implausible, but it doesn't cost us
+ * much to support them.
+ */
+
static const char *hexchars="0123456789abcdef";
static void emsa_pkcs1(MP_INT *n, MP_INT *m,
const uint8_t *data, int32_t datalen)
{
- char buff[2048];
+ char buff[2*RSA_MAX_MODBYTES + 1];
int msize, i;
/* RSA PKCS#1 v1.5 signature padding:
mpz_init(&u);
mpz_init(&v);
- mpz_powm(&u, &a, &st->dp, &st->p);
- mpz_powm(&v, &a, &st->dq, &st->q);
+ mpz_powm_sec(&u, &a, &st->dp, &st->p);
+ mpz_powm_sec(&v, &a, &st->dq, &st->q);
mpz_sub(&tmp, &u, &v);
mpz_mul(&tmp2, &tmp, &st->w);
mpz_add(&tmp, &tmp2, &v);
item_t *i;
string_t e,n;
- st=safe_malloc(sizeof(*st),"rsapub_apply");
+ NEW(st);
st->cl.description="rsapub";
st->cl.type=CL_RSAPUBKEY;
st->cl.apply=NULL;
} else {
cfgfatal(loc,"rsa-public","you must provide an encryption key\n");
}
+ if (mpz_sizeinbase(&st->e, 256) > RSA_MAX_MODBYTES) {
+ cfgfatal(loc, "rsa-public", "implausibly large public exponent\n");
+ }
i=list_elem(args,1);
if (i) {
} else {
cfgfatal(loc,"rsa-public","you must provide a modulus\n");
}
+ if (mpz_sizeinbase(&st->n, 256) > RSA_MAX_MODBYTES) {
+ cfgfatal(loc, "rsa-public", "implausibly large modulus\n");
+ }
return new_closure(&st->cl);
}
MP_INT e,d,iqmp,tmp,tmp2,tmp3;
bool_t valid;
- st=safe_malloc(sizeof(*st),"rsapriv_apply");
+ NEW(st);
st->cl.description="rsapriv";
st->cl.type=CL_RSAPRIVKEY;
st->cl.apply=NULL;
i=list_elem(args,0);
if (i) {
if (i->type!=t_string) {
- cfgfatal(i->loc,"rsa-public","first argument must be a string\n");
+ cfgfatal(i->loc,"rsa-private","first argument must be a string\n");
}
filename=i->data.string;
} else {
/* Read the public key */
keyfile_get_int(loc,f); /* Not sure what this is */
length=(keyfile_get_short(loc,f)+7)/8;
- if (length>1024) {
+ if (length>RSA_MAX_MODBYTES) {
cfgfatal(loc,"rsa-private","implausible length %ld for modulus\n",
length);
}
read_mpbin(&st->n,b,length);
free(b);
length=(keyfile_get_short(loc,f)+7)/8;
- if (length>1024) {
+ if (length>RSA_MAX_MODBYTES) {
cfgfatal(loc,"rsa-private","implausible length %ld for e\n",length);
}
b=safe_malloc(length,"rsapriv_apply");
/* Read d */
length=(keyfile_get_short(loc,f)+7)/8;
- if (length>1024) {
+ if (length>RSA_MAX_MODBYTES) {
cfgfatal(loc,"rsa-private","implausibly long (%ld) decryption key\n",
length);
}
free(b);
/* Read iqmp (inverse of q mod p) */
length=(keyfile_get_short(loc,f)+7)/8;
- if (length>1024) {
+ if (length>RSA_MAX_MODBYTES) {
cfgfatal(loc,"rsa-private","implausibly long (%ld)"
" iqmp auxiliary value\n", length);
}
free(b);
/* Read q (the smaller of the two primes) */
length=(keyfile_get_short(loc,f)+7)/8;
- if (length>1024) {
+ if (length>RSA_MAX_MODBYTES) {
cfgfatal(loc,"rsa-private","implausibly long (%ld) q value\n",
length);
}
free(b);
/* Read p (the larger of the two primes) */
length=(keyfile_get_short(loc,f)+7)/8;
- if (length>1024) {
+ if (length>RSA_MAX_MODBYTES) {
cfgfatal(loc,"rsa-private","implausibly long (%ld) p value\n",
length);
}