X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ian/git?p=secnet.git;a=blobdiff_plain;f=rsa.c;h=f7dd69db6f69115e03c94779a2529468b642619f;hp=2b4c7293f48071806a7ce4bcde40349a029a823e;hb=HEAD;hpb=ff05a229397c75142725f45cad191ce4a00625ce diff --git a/rsa.c b/rsa.c index 2b4c729..6a89b21 100644 --- a/rsa.c +++ b/rsa.c @@ -1,100 +1,306 @@ +/* + * 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 +#include #include #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>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; id, &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>4]; - buff[5+i*2]=hexchars[data[i]&0xf]; - } - buff[4+datalen*2]=0; - - for (i=datalen*2+4; iops.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); @@ -107,53 +313,145 @@ static bool_t rsa_sig_check(void *sst, uint8_t *data, uint32_t datalen, 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; @@ -163,7 +461,7 @@ static uint32_t keyfile_get_int(FILE *f) 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; @@ -171,158 +469,349 @@ static uint16_t keyfile_get_short(FILE *f) 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);