+/*
+ * 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.
+ */
+
+
#include <stdio.h>
+#include <string.h>
#include <gmp.h>
#include "secnet.h"
#include "util.h"
+#include "unaligned.h"
#define AUTHFILE_ID_STRING "SSH PRIVATE KEY FILE FORMAT 1.1\n"
+#define mpp(s,n) do { char *p = mpz_get_str(NULL,16,n); printf("%s 0x%sL\n", s, p); free(p); } while (0)
+
+struct rsacommon {
+ uint8_t *hashbuf;
+};
+
+#define FREE(b) ({ free((b)); (b)=0; })
+
+struct load_ctx {
+ void (*verror)(struct load_ctx *l, struct cloc loc,
+ FILE *maybe_f,
+ const char *message, va_list args);
+ bool_t (*postreadcheck)(struct load_ctx *l, FILE *f);
+ const char *what;
+ dict_t *deprdict; /* used only to look up hash */
+ struct cloc loc;
+ union {
+ struct {
+ struct log_if *log;
+ } tryload;
+ } u;
+};
+
+static void load_err(struct load_ctx *l,
+ const struct cloc *maybe_loc, FILE *maybe_f,
+ const char *fmt, ...)
+{
+ va_list al;
+ va_start(al,fmt);
+ l->verror(l, maybe_loc ? *maybe_loc : l->loc, maybe_f,fmt,al);
+ va_end(al);
+}
+
+FORMAT(printf,4,0)
+static void verror_tryload(struct load_ctx *l, struct cloc loc,
+ FILE *maybe_f,
+ const char *message, va_list args)
+{
+ int class=M_ERR;
+ slilog_part(l->u.tryload.log,class,"%s: ",l->what);
+ vslilog(l->u.tryload.log,class,message,args);
+}
+
+static void verror_cfgfatal(struct load_ctx *l, struct cloc loc,
+ FILE *maybe_f,
+ const char *message, va_list args)
+{
+ vcfgfatal_maybefile(maybe_f,l->loc,l->what,message,args,"");
+}
+
struct rsapriv {
closure_t cl;
- struct rsaprivkey_if ops;
+ struct sigprivkey_if ops;
struct cloc loc;
- MP_INT d;
+ struct rsacommon common;
MP_INT n;
+ MP_INT p, dp;
+ MP_INT q, dq;
+ MP_INT w;
};
+
+#define RSAPUB_BNS(each) \
+ each(0,e,"public exponent") \
+ each(1,n,"modulus")
+
+#define RSAPUB_LOADCORE_PASSBN(ix,en,what) \
+ en##s, en##_loc,
+
+#define RSAPUB_INIT_ST_BN( ix,en,what) mpz_init (&st->en);
+#define RSAPUB_CLEAR_ST_BN(ix,en,what) mpz_clear(&st->en);
+
struct rsapub {
closure_t cl;
- struct rsapubkey_if ops;
+ struct sigpubkey_if ops;
struct cloc loc;
+ struct rsacommon common;
MP_INT e;
MP_INT n;
};
/* Sign data. NB data must be smaller than modulus */
-static char *hexchars="0123456789abcdef";
+#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 string_t rsa_sign(void *sst, uint8_t *data, uint32_t datalen)
+static void rsa_sethash(struct load_ctx *l,
+ struct rsacommon *c,
+ const struct hash_if **in_ops)
{
- struct rsapriv *st=sst;
- MP_INT a, b;
- char buff[2048];
- int msize, i;
- string_t signature;
+ struct hash_if *hash=0;
+ if (l->deprdict)
+ hash=find_cl_if(l->deprdict,"hash",CL_HASH,False,"site",l->loc);
+ if (!hash)
+ hash=sha1_hash_if;
+ c->hashbuf=safe_malloc(hash->hlen, "generate_msg");
+ *in_ops=hash;
+}
- mpz_init(&a);
- mpz_init(&b);
+static void rsacommon_dispose(struct rsacommon *c)
+{
+ free(c->hashbuf);
+}
- msize=mpz_sizeinbase(&st->n, 16);
+static void emsa_pkcs1(MP_INT *n, MP_INT *m,
+ const uint8_t *data, int32_t datalen)
+{
+ char buff[2*RSA_MAX_MODBYTES + 1];
+ int msize, i;
- if (datalen*2+4>=msize) {
- fatal("rsa_sign: message too big\n");
+ /* RSA PKCS#1 v1.5 signature padding:
+ *
+ * <------------ msize hex digits ---------->
+ *
+ * 00 01 ff ff .... ff ff 00 vv vv vv .... vv
+ *
+ * <--- datalen -->
+ * bytes
+ * = datalen*2 hex digits
+ *
+ * NB that according to PKCS#1 v1.5 we're supposed to include a
+ * hash function OID in the data. We don't do that (because we
+ * don't have the hash function OID to hand here), thus violating
+ * the spec in a way that affects interop but not security.
+ *
+ * -iwj 17.9.2002
+ */
+
+ msize=mpz_sizeinbase(n, 16);
+
+ if (datalen*2+6>=msize) {
+ fatal("rsa: message too big");
}
strcpy(buff,"0001");
for (i=0; i<datalen; i++) {
- buff[4+i*2]=hexchars[(data[i]&0xf0)>>4];
- buff[5+i*2]=hexchars[data[i]&0xf];
+ buff[msize+(-datalen+i)*2]=hexchars[(data[i]&0xf0)>>4];
+ buff[msize+(-datalen+i)*2+1]=hexchars[data[i]&0xf];
}
- buff[4+datalen*2]=0;
- for (i=datalen*2+4; i<msize; i++)
- buff[i]='f';
+ buff[msize-datalen*2-2]= '0';
+ buff[msize-datalen*2-1]= '0';
+
+ for (i=4; i<msize-datalen*2-2; i++)
+ buff[i]='f';
buff[msize]=0;
- mpz_set_str(&a, buff, 16);
+ mpz_set_str(m, buff, 16);
+}
+
+static bool_t rsa_sign(void *sst, uint8_t *data, int32_t datalen,
+ struct buffer_if *msg)
+{
+ struct rsapriv *st=sst;
+ MP_INT a, b, u, v, tmp, tmp2;
+ string_t signature = 0;
+ bool_t ok;
+
+ mpz_init(&a);
+ mpz_init(&b);
- mpz_powm(&b, &a, &st->d, &st->n);
+ hash_hash(st->ops.hash,data,datalen,st->common.hashbuf);
+ /* Construct the message representative. */
+ emsa_pkcs1(&st->n, &a, st->common.hashbuf, st->ops.hash->hlen);
+
+ /*
+ * Produce an RSA signature (a^d mod n) using the Chinese
+ * Remainder Theorem. We compute:
+ *
+ * u = a^dp mod p (== a^d mod p, since dp == d mod (p-1))
+ * v = a^dq mod q (== a^d mod q, similarly)
+ *
+ * We also know w == iqmp * q, which has the property that w ==
+ * 0 mod q and w == 1 mod p. So (1-w) has the reverse property
+ * (congruent to 0 mod p and to 1 mod q). Hence we now compute
+ *
+ * b = w * u + (1-w) * v
+ * = w * (u-v) + v
+ *
+ * so that b is congruent to a^d both mod p and mod q. Hence b,
+ * reduced mod n, is the required signature.
+ */
+ mpz_init(&tmp);
+ mpz_init(&tmp2);
+ mpz_init(&u);
+ mpz_init(&v);
+
+ 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);
+ mpz_mod(&b, &tmp, &st->n);
+
+ mpz_clear(&tmp);
+ mpz_clear(&tmp2);
+ mpz_clear(&u);
+ mpz_clear(&v);
signature=write_mpstring(&b);
+ uint8_t *op = buf_append(msg,2);
+ if (!op) { ok=False; goto out; }
+ size_t l = strlen(signature);
+ assert(l < 65536);
+ put_uint16(op, l);
+ op = buf_append(msg,l);
+ if (!op) { ok=False; goto out; }
+ memcpy(op, signature, l);
+
+ ok = True;
+
+ out:
+ free(signature);
mpz_clear(&b);
mpz_clear(&a);
- return signature;
+ return ok;
}
-static bool_t rsa_sig_check(void *sst, uint8_t *data, uint32_t datalen,
- string_t signature)
+static bool_t rsa_sig_unpick(void *sst, struct buffer_if *msg,
+ struct alg_msg_data *sig)
+{
+ uint8_t *lp = buf_unprepend(msg, 2);
+ if (!lp) return False;
+ sig->len = get_uint16(lp);
+ sig->start = buf_unprepend(msg, sig->len);
+ if (!sig->start) return False;
+
+ /* In `rsa_sig_check' below, we assume that we can write a nul
+ * terminator following the signature. Make sure there's enough space.
+ */
+ if (msg->start >= msg->base + msg->alloclen)
+ return False;
+
+ return True;
+}
+
+static sig_checksig_fn rsa_sig_check;
+static bool_t rsa_sig_check(void *sst, uint8_t *data, int32_t datalen,
+ const struct alg_msg_data *sig)
{
struct rsapub *st=sst;
MP_INT a, b, c;
- char buff[2048];
- int msize, i;
bool_t ok;
mpz_init(&a);
mpz_init(&b);
mpz_init(&c);
- msize=mpz_sizeinbase(&st->n, 16);
-
- strcpy(buff,"0001");
-
- for (i=0; i<datalen; i++) {
- buff[4+i*2]=hexchars[(data[i]&0xf0)>>4];
- buff[5+i*2]=hexchars[data[i]&0xf];
- }
- buff[4+datalen*2]=0;
-
- for (i=datalen*2+4; i<msize; i++)
- buff[i]='f';
+ hash_hash(st->ops.hash,data,datalen,st->common.hashbuf);
+ emsa_pkcs1(&st->n, &a, st->common.hashbuf, st->ops.hash->hlen);
- buff[msize]=0;
-
- mpz_set_str(&a, buff, 16);
-
- mpz_set_str(&b, signature, 16);
+ /* Terminate signature with a '0' - already checked that this will fit */
+ int save = sig->start[sig->len];
+ sig->start[sig->len] = 0;
+ mpz_set_str(&b, sig->start, 16);
+ sig->start[sig->len] = save;
mpz_powm(&c, &b, &st->e, &st->n);
return ok;
}
-static list_t *rsapub_apply(closure_t *self, struct cloc loc, dict_t *context,
- list_t *args)
+static void rsapub_dispose(void *sst) {
+ struct rsapub *st=sst;
+
+ if (!st) return;
+ RSAPUB_BNS(RSAPUB_CLEAR_ST_BN)
+ rsacommon_dispose(&st->common);
+ free(st);
+}
+
+#define RSAPUB_LOADCORE_DEFBN(ix,en,what) \
+ const char *en##s, struct cloc en##_loc,
+
+#define LDPUBFATAL(lc,...) ({ \
+ load_err(l,(lc),0,__VA_ARGS__); \
+ goto error_out; \
+ })
+
+static struct rsapub *rsa_loadpub_core(RSAPUB_BNS(RSAPUB_LOADCORE_DEFBN)
+ struct load_ctx *l)
{
struct rsapub *st;
- 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.type=CL_SIGPUBKEY;
st->cl.apply=NULL;
st->cl.interface=&st->ops;
st->ops.st=st;
+ st->common.hashbuf=NULL;
+ st->ops.unpick=rsa_sig_unpick;
st->ops.check=rsa_sig_check;
- st->loc=loc;
-
- i=list_elem(args,0);
- if (i) {
- if (i->type!=t_string) {
- cfgfatal(i->loc,"rsa-public","first argument must be a string");
- }
- e=i->data.string;
- if (mpz_init_set_str(&st->e,e,10)!=0) {
- cfgfatal(i->loc,"rsa-public","encryption key \"%s\" is not a "
- "decimal number string\n",e);
- }
- } else {
- cfgfatal(loc,"rsa-public","you must provide an encryption key\n");
- }
-
- i=list_elem(args,1);
- if (i) {
- if (i->type!=t_string) {
- cfgfatal(i->loc,"rsa-public","second argument must be a string");
- }
- n=i->data.string;
- if (mpz_init_set_str(&st->n,n,10)!=0) {
- cfgfatal(i->loc,"rsa-public","modulus \"%s\" is not a decimal "
- "number string\n",n);
- }
- } else {
- cfgfatal(loc,"rsa-public","you must provide a modulus\n");
+ st->ops.hash=0;
+ st->ops.dispose=rsapub_dispose;
+ st->loc=l->loc;
+ RSAPUB_BNS(RSAPUB_INIT_ST_BN)
+
+#define RSAPUB_LOADCORE_GETBN(ix,en,what) \
+ if (mpz_init_set_str(&st->en,en##s,10)!=0) { \
+ LDPUBFATAL(&en##_loc, what " \"%s\" is not a " \
+ "decimal number string",en##s); \
+ } \
+ if (mpz_sizeinbase(&st->en, 256) > RSA_MAX_MODBYTES) { \
+ LDPUBFATAL(&en##_loc, "implausibly large " what); \
}
+
+ RSAPUB_BNS(RSAPUB_LOADCORE_GETBN)
+
+ rsa_sethash(l,&st->common,&st->ops.hash);
+
+ return st;
+
+ error_out:
+ rsapub_dispose(st);
+ return 0;
+}
+
+static list_t *rsapub_apply(closure_t *self, struct cloc loc, dict_t *context,
+ list_t *args)
+{
+ struct load_ctx l[1];
+ l->verror=verror_cfgfatal;
+ l->postreadcheck=0;
+ l->what="rsa-public";
+ l->deprdict=context;
+ l->loc=loc;
+
+#define RSAPUB_APPLY_GETBN(ix,en,what) \
+ item_t *en##i; \
+ const char *en##s; \
+ en##i=list_elem(args,ix); \
+ if (!en##i) \
+ cfgfatal(loc,"rsa-public", \
+ "you must provide an encryption key\n"); \
+ struct cloc en##_loc=en##i->loc; \
+ if (en##i->type!=t_string) \
+ cfgfatal(en##_loc,"rsa-public", \
+ "first argument must be a string\n"); \
+ en##s=en##i->data.string;
+
+ RSAPUB_BNS(RSAPUB_APPLY_GETBN)
+
+ struct rsapub *st=rsa_loadpub_core(RSAPUB_BNS(RSAPUB_LOADCORE_PASSBN)
+ l);
+
return new_closure(&st->cl);
}
-static uint32_t keyfile_get_int(FILE *f)
+bool_t rsa1_loadpub(const struct sigscheme_info *algo,
+ struct buffer_if *pubkeydata,
+ struct sigpubkey_if **sigpub_r,
+ closure_t **closure_r,
+ struct log_if *log, struct cloc loc)
+{
+ struct rsapub *st=0;
+
+ struct load_ctx l[1];
+ l->verror=verror_tryload;
+ l->postreadcheck=0;
+ l->what="rsa1_loadpub";
+ l->deprdict=0;
+ l->loc=loc;
+ l->u.tryload.log=log;
+
+ char *nul=buf_append(pubkeydata,1);
+ if (!nul) LDPUBFATAL(0,"rsa1 public key data too long for extra nul");
+ *nul=0;
+
+ const char *delim=" \t\n";
+ char *saveptr;
+ /*unused*/ strtok_r(pubkeydata->start,delim,&saveptr);
+
+#define RSAPUB_TRYLOAD_GETBN(ix,en,what) \
+ struct cloc en##_loc=loc; \
+ const char *en##s=strtok_r(0,delim,&saveptr); \
+ if (!en##s) LDPUBFATAL(0,"end of pubkey data looking for " what);
+
+ RSAPUB_BNS(RSAPUB_TRYLOAD_GETBN);
+
+ st=rsa_loadpub_core(RSAPUB_BNS(RSAPUB_LOADCORE_PASSBN) l);
+ if (!st) goto error_out;
+
+ *sigpub_r=&st->ops;
+ *closure_r=&st->cl;
+ return True;
+
+ error_out:
+ rsapub_dispose(st);
+ return False;
+}
+
+#define LDFATAL(...) ({ load_err(l,0,0,__VA_ARGS__); goto error_out; })
+#define LDFATAL_FILE(...) ({ load_err(l,0,f,__VA_ARGS__); goto error_out; })
+#define KEYFILE_GET(is) ({ \
+ uint##is##_t keyfile_get_tmp=keyfile_get_##is(l,f); \
+ if (!l->postreadcheck(l,f)) goto error_out; \
+ keyfile_get_tmp; \
+ })
+
+static uint32_t keyfile_get_32(struct load_ctx *l, FILE *f)
{
uint32_t r;
r=fgetc(f)<<24;
return r;
}
-static uint16_t keyfile_get_short(FILE *f)
+static uint16_t keyfile_get_16(struct load_ctx *l, FILE *f)
{
uint16_t r;
r=fgetc(f)<<8;
return r;
}
-static list_t *rsapriv_apply(closure_t *self, struct cloc loc, dict_t *context,
- list_t *args)
+static void rsapriv_dispose(void *sst)
{
- struct rsapriv *st;
- FILE *f;
- string_t filename;
- item_t *i;
+ struct rsapriv *st=sst;
+ mpz_clear(&st->n);
+ mpz_clear(&st->p); mpz_clear(&st->dp);
+ mpz_clear(&st->q); mpz_clear(&st->dq);
+ mpz_clear(&st->w);
+ rsacommon_dispose(&st->common);
+ free(st);
+}
+
+static struct rsapriv *rsa_loadpriv_core(struct load_ctx *l,
+ FILE *f, struct cloc loc,
+ bool_t do_validity_check)
+{
+ struct rsapriv *st=0;
long length;
- uint8_t *b, *c;
+ uint8_t *b=0, *c=0;
int cipher_type;
- MP_INT e,sig,plain,check;
+ MP_INT e,d,iqmp,tmp,tmp2,tmp3;
+ bool_t valid;
+
+ mpz_init(&e);
+ mpz_init(&d);
+ mpz_init(&iqmp);
+ mpz_init(&tmp);
+ mpz_init(&tmp2);
+ mpz_init(&tmp3);
- st=safe_malloc(sizeof(*st),"rsapriv_apply");
+ NEW(st);
st->cl.description="rsapriv";
- st->cl.type=CL_RSAPRIVKEY;
+ st->cl.type=CL_SIGPRIVKEY;
st->cl.apply=NULL;
st->cl.interface=&st->ops;
st->ops.st=st;
+ st->common.hashbuf=NULL;
st->ops.sign=rsa_sign;
+ st->ops.hash=0;
+ st->ops.dispose=rsapriv_dispose;
st->loc=loc;
+ mpz_init(&st->n);
+ mpz_init(&st->q);
+ mpz_init(&st->p);
+ mpz_init(&st->dp);
+ mpz_init(&st->dq);
+ mpz_init(&st->w);
- /* Argument is filename pointing to SSH1 private key file */
- i=list_elem(args,0);
- if (i) {
- if (i->type!=t_string) {
- cfgfatal(i->loc,"rsa-public","first argument must be a string");
- }
- filename=i->data.string;
- } else {
- filename=""; /* Make compiler happy */
- cfgfatal(loc,"rsa-private","you must provide a filename\n");
- }
-
- f=fopen(filename,"rb");
if (!f) {
- if (just_check_config) {
- Message(M_WARNING,"rsa-private (%s:%d): cannot open keyfile "
- "\"%s\"; assuming it's valid while we check the "
- "rest of the configuration\n",loc.file,loc.line,filename);
- goto assume_valid;
- } else {
- fatal_perror("rsa-private (%s:%d): cannot open file \"%s\"",
- loc.file,loc.line,filename);
- }
+ assert(just_check_config);
+ goto assume_valid;
}
/* Check that the ID string is correct */
length=strlen(AUTHFILE_ID_STRING)+1;
b=safe_malloc(length,"rsapriv_apply");
if (fread(b,length,1,f)!=1 || memcmp(b,AUTHFILE_ID_STRING,length)!=0) {
- cfgfatal(loc,"rsa-private","file \"%s\" is not a "
- "SSH1 private keyfile\n",filename);
+ LDFATAL_FILE("failed to read magic ID"
+ " string from SSH1 private keyfile\n");
}
- free(b);
+ FREE(b);
cipher_type=fgetc(f);
- keyfile_get_int(f); /* "Reserved data" */
+ KEYFILE_GET(32); /* "Reserved data" */
if (cipher_type != 0) {
- cfgfatal(loc,"rsa-private","we don't support encrypted keyfiles\n");
+ LDFATAL("we don't support encrypted keyfiles\n");
}
/* Read the public key */
- keyfile_get_int(f); /* Not sure what this is */
- length=(keyfile_get_short(f)+7)/8;
- if (length>1024) {
- cfgfatal(loc,"rsa-private","implausible length %ld for modulus\n",
+ KEYFILE_GET(32); /* Not sure what this is */
+ length=(KEYFILE_GET(16)+7)/8;
+ if (length>RSA_MAX_MODBYTES) {
+ LDFATAL("implausible length %ld for modulus\n",
length);
}
b=safe_malloc(length,"rsapriv_apply");
if (fread(b,length,1,f) != 1) {
- cfgfatal(loc,"rsa-private","error reading modulus\n");
+ LDFATAL_FILE("error reading modulus\n");
}
- mpz_init(&st->n);
read_mpbin(&st->n,b,length);
- free(b);
- length=(keyfile_get_short(f)+7)/8;
- if (length>1024) {
- cfgfatal(loc,"rsa-private","implausible length %ld for e\n",length);
+ FREE(b);
+ length=(KEYFILE_GET(16)+7)/8;
+ if (length>RSA_MAX_MODBYTES) {
+ LDFATAL("implausible length %ld for e\n",length);
}
b=safe_malloc(length,"rsapriv_apply");
if (fread(b,length,1,f)!=1) {
- cfgfatal(loc,"rsa-private","error reading e\n");
+ LDFATAL_FILE("error reading e\n");
}
- mpz_init(&e);
read_mpbin(&e,b,length);
- free(b);
+ FREE(b);
- length=keyfile_get_int(f);
+ length=KEYFILE_GET(32);
if (length>1024) {
- cfgfatal(loc,"rsa-private","implausibly long (%ld) key comment\n",
+ LDFATAL("implausibly long (%ld) key comment\n",
length);
}
c=safe_malloc(length+1,"rsapriv_apply");
if (fread(c,length,1,f)!=1) {
- cfgfatal(loc,"rsa-private","error reading key comment\n");
+ LDFATAL_FILE("error reading key comment\n");
}
c[length]=0;
/* Check that the next two pairs of characters are identical - the
keyfile is not encrypted, so they should be */
- if (keyfile_get_short(f) != keyfile_get_short(f)) {
- cfgfatal(loc,"rsa-private","corrupt keyfile\n");
+
+ if (KEYFILE_GET(16) != KEYFILE_GET(16)) {
+ LDFATAL("corrupt keyfile\n");
}
/* Read d */
- length=(keyfile_get_short(f)+7)/8;
- if (length>1024) {
- cfgfatal(loc,"rsa-private","implausibly long (%ld) decryption key\n",
+ length=(KEYFILE_GET(16)+7)/8;
+ if (length>RSA_MAX_MODBYTES) {
+ LDFATAL("implausibly long (%ld) decryption key\n",
+ length);
+ }
+ b=safe_malloc(length,"rsapriv_apply");
+ if (fread(b,length,1,f)!=1) {
+ LDFATAL_FILE("error reading decryption key\n");
+ }
+ read_mpbin(&d,b,length);
+ FREE(b);
+ /* Read iqmp (inverse of q mod p) */
+ length=(KEYFILE_GET(16)+7)/8;
+ if (length>RSA_MAX_MODBYTES) {
+ LDFATAL("implausibly long (%ld)"
+ " iqmp auxiliary value\n", length);
+ }
+ b=safe_malloc(length,"rsapriv_apply");
+ if (fread(b,length,1,f)!=1) {
+ LDFATAL_FILE("error reading decryption key\n");
+ }
+ read_mpbin(&iqmp,b,length);
+ FREE(b);
+ /* Read q (the smaller of the two primes) */
+ length=(KEYFILE_GET(16)+7)/8;
+ if (length>RSA_MAX_MODBYTES) {
+ LDFATAL("implausibly long (%ld) q value\n",
+ length);
+ }
+ b=safe_malloc(length,"rsapriv_apply");
+ if (fread(b,length,1,f)!=1) {
+ LDFATAL_FILE("error reading q value\n");
+ }
+ read_mpbin(&st->q,b,length);
+ FREE(b);
+ /* Read p (the larger of the two primes) */
+ length=(KEYFILE_GET(16)+7)/8;
+ if (length>RSA_MAX_MODBYTES) {
+ LDFATAL("implausibly long (%ld) p value\n",
length);
}
b=safe_malloc(length,"rsapriv_apply");
if (fread(b,length,1,f)!=1) {
- cfgfatal(loc,"rsa-private","error reading decryption key\n");
+ LDFATAL_FILE("error reading p value\n");
}
- mpz_init(&st->d);
- read_mpbin(&st->d,b,length);
- free(b);
+ read_mpbin(&st->p,b,length);
+ FREE(b);
- if (fclose(f)!=0) {
- fatal_perror("rsa-private (%s:%d): fclose",loc.file,loc.line);
+ if (ferror(f)) {
+ fatal_perror("rsa-private (%s:%d): ferror",loc.file,loc.line);
+ }
+
+ rsa_sethash(l,&st->common,&st->ops.hash);
+
+ /*
+ * Now verify the validity of the key, and set up the auxiliary
+ * values for fast CRT signing.
+ */
+ valid=False;
+ if (do_validity_check) {
+ /* Verify that p*q is equal to n. */
+ mpz_mul(&tmp, &st->p, &st->q);
+ if (mpz_cmp(&tmp, &st->n) != 0)
+ goto done_checks;
+
+ /*
+ * Verify that d*e is congruent to 1 mod (p-1), and mod
+ * (q-1). This is equivalent to it being congruent to 1 mod
+ * lambda(n) = lcm(p-1,q-1). The usual `textbook' condition,
+ * that d e == 1 (mod (p-1)(q-1)) is sufficient, but not
+ * actually necessary.
+ */
+ mpz_mul(&tmp, &d, &e);
+ mpz_sub_ui(&tmp2, &st->p, 1);
+ mpz_mod(&tmp3, &tmp, &tmp2);
+ if (mpz_cmp_si(&tmp3, 1) != 0)
+ goto done_checks;
+ mpz_sub_ui(&tmp2, &st->q, 1);
+ mpz_mod(&tmp3, &tmp, &tmp2);
+ if (mpz_cmp_si(&tmp3, 1) != 0)
+ goto done_checks;
+
+ /* Verify that q*iqmp is congruent to 1 mod p. */
+ mpz_mul(&tmp, &st->q, &iqmp);
+ mpz_mod(&tmp2, &tmp, &st->p);
+ if (mpz_cmp_si(&tmp2, 1) != 0)
+ goto done_checks;
+ }
+ /* Now we know the key is valid (or we don't care). */
+ valid = True;
+
+ /*
+ * Now we compute auxiliary values dp, dq and w to allow us
+ * to use the CRT optimisation when signing.
+ *
+ * dp == d mod (p-1) so that a^dp == a^d mod p, for all a
+ * dq == d mod (q-1) similarly mod q
+ * w == iqmp * q so that w == 0 mod q, and w == 1 mod p
+ */
+ mpz_sub_ui(&tmp, &st->p, 1);
+ mpz_mod(&st->dp, &d, &tmp);
+ mpz_sub_ui(&tmp, &st->q, 1);
+ mpz_mod(&st->dq, &d, &tmp);
+ mpz_mul(&st->w, &iqmp, &st->q);
+
+done_checks:
+ if (!valid) {
+ LDFATAL("file does not contain a "
+ "valid RSA key!\n");
+ }
+
+assume_valid:
+out:
+ mpz_clear(&tmp);
+ mpz_clear(&tmp2);
+ mpz_clear(&tmp3);
+
+ FREE(b);
+ FREE(c);
+ mpz_clear(&e);
+ mpz_clear(&d);
+ mpz_clear(&iqmp);
+
+ return st;
+
+error_out:
+ if (st) rsapriv_dispose(st);
+ st=0;
+ goto out;
+}
+
+static bool_t postreadcheck_tryload(struct load_ctx *l, FILE *f)
+{
+ assert(!ferror(f));
+ if (feof(f)) { load_err(l,0,0,"eof mid-integer"); return False; }
+ return True;
+}
+
+bool_t rsa1_loadpriv(const struct sigscheme_info *algo,
+ struct buffer_if *privkeydata,
+ struct sigprivkey_if **sigpriv_r,
+ closure_t **closure_r,
+ struct log_if *log, struct cloc loc)
+{
+ FILE *f=0;
+ struct rsapriv *st=0;
+
+ f=fmemopen(privkeydata->start,privkeydata->size,"r");
+ if (!f) {
+ slilog(log,M_ERR,"failed to fmemopen private key file\n");
+ goto error_out;
}
- /* Now do trial signature/check to make sure it's a real keypair:
- sign the comment string! */
+ struct load_ctx l[1];
+ l->what="rsa1priv load";
+ l->verror=verror_tryload;
+ l->postreadcheck=postreadcheck_tryload;
+ l->deprdict=0;
+ l->loc=loc;
+ l->u.tryload.log=log;
+
+ st=rsa_loadpriv_core(l,f,loc,False);
+ if (!st) goto error_out;
+ goto out;
+
+ error_out:
+ FREE(st);
+ out:
+ if (f) fclose(f);
+ if (!st) return False;
+ *sigpriv_r=&st->ops;
+ *closure_r=&st->cl;
+ return True;
+}
+
+static bool_t postreadcheck_apply(struct load_ctx *l, FILE *f)
+{
+ cfgfile_postreadcheck(l->loc,f);
+ return True;
+}
+
+static list_t *rsapriv_apply(closure_t *self, struct cloc loc, dict_t *context,
+ list_t *args)
+{
+ struct rsapriv *st;
+ item_t *i;
+ cstring_t filename;
+ FILE *f;
+ struct load_ctx l[1];
+
+ l->what="rsa-private";
+ l->verror=verror_cfgfatal;
+ l->postreadcheck=postreadcheck_apply;
+ l->deprdict=context;
+ l->loc=loc;
+
+ /* Argument is filename pointing to SSH1 private key file */
+ i=list_elem(args,0);
+ if (i) {
+ if (i->type!=t_string) {
+ cfgfatal(i->loc,"rsa-private","first argument must be a string\n");
+ }
+ filename=i->data.string;
+ } else {
+ filename=NULL; /* Make compiler happy */
+ cfgfatal(i->loc,"rsa-private","you must provide a filename\n");
+ }
+
+ f=fopen(filename,"rb");
+ if (!f) {
+ if (just_check_config) {
+ Message(M_WARNING,"rsa-private (%s:%d): cannot open keyfile "
+ "\"%s\"; assuming it's valid while we check the "
+ "rest of the configuration\n",loc.file,loc.line,filename);
+ } else {
+ fatal_perror("rsa-private (%s:%d): cannot open file \"%s\"",
+ loc.file,loc.line,filename);
+ }
+ }
+
+ bool_t do_validity_check=True;
i=list_elem(args,1);
if (i && i->type==t_bool && i->data.bool==False) {
Message(M_INFO,"rsa-private (%s:%d): skipping RSA key validity "
"check\n",loc.file,loc.line);
- } else {
- mpz_init(&sig);
- mpz_init(&plain);
- mpz_init(&check);
- read_mpbin(&plain,c,strlen(c));
- mpz_powm(&sig, &plain, &st->d, &st->n);
- mpz_powm(&check, &sig, &e, &st->n);
- if (mpz_cmp(&plain,&check)!=0) {
- cfgfatal(loc,"rsa-private","file \"%s\" does not contain a "
- "valid RSA key!\n",filename);
- }
- mpz_clear(&sig);
- mpz_clear(&plain);
- mpz_clear(&check);
+ do_validity_check=False;
}
- free(c);
- mpz_clear(&e);
-
-assume_valid:
+ st=rsa_loadpriv_core(l,f,loc,do_validity_check);
+ fclose(f);
return new_closure(&st->cl);
}
-init_module rsa_module;
void rsa_module(dict_t *dict)
{
add_closure(dict,"rsa-private",rsapriv_apply);
~ian / secnet.git / blobdiff