1 6e527fbc 2005-02-13 devnull #include "std.h"
  2 6e527fbc 2005-02-13 devnull #include "dat.h"
  3 6e527fbc 2005-02-13 devnull 
  4 6e527fbc 2005-02-13 devnull /*
  5 6e527fbc 2005-02-13 devnull  * RSA authentication.
  6 fa325e9b 2020-01-10 cross  *
  7 ce94dbe6 2005-02-13 devnull  * Encrypt/Decrypt:
  8 6e527fbc 2005-02-13 devnull  *	start n=xxx ek=xxx
  9 6e527fbc 2005-02-13 devnull  *	write msg
 10 ce94dbe6 2005-02-13 devnull  *	read encrypt/decrypt(msg)
 11 6e527fbc 2005-02-13 devnull  *
 12 6e527fbc 2005-02-13 devnull  * Sign (PKCS #1 using hash=sha1 or hash=md5)
 13 6e527fbc 2005-02-13 devnull  *	start n=xxx ek=xxx
 14 6e527fbc 2005-02-13 devnull  *	write hash(msg)
 15 6e527fbc 2005-02-13 devnull  *	read signature(hash(msg))
 16 fa325e9b 2020-01-10 cross  *
 17 ce94dbe6 2005-02-13 devnull  * Verify:
 18 ce94dbe6 2005-02-13 devnull  *	start n=xxx ek=xxx
 19 ce94dbe6 2005-02-13 devnull  *	write hash(msg)
 20 ce94dbe6 2005-02-13 devnull  *	write signature(hash(msg))
 21 ce94dbe6 2005-02-13 devnull  *	read ok or fail
 22 ce94dbe6 2005-02-13 devnull  *
 23 6e527fbc 2005-02-13 devnull  * all numbers are hexadecimal biginits parsable with strtomp.
 24 6e527fbc 2005-02-13 devnull  * must be lower case for attribute matching in start.
 25 6e527fbc 2005-02-13 devnull  */
 26 6e527fbc 2005-02-13 devnull 
 27 6e527fbc 2005-02-13 devnull static int
 28 ce94dbe6 2005-02-13 devnull xrsadecrypt(Conv *c)
 29 6e527fbc 2005-02-13 devnull {
 30 ce94dbe6 2005-02-13 devnull 	char *txt, buf[4096], *role;
 31 ce94dbe6 2005-02-13 devnull 	int n, ret;
 32 ce94dbe6 2005-02-13 devnull 	mpint *m, *mm;
 33 6e527fbc 2005-02-13 devnull 	Key *k;
 34 ce94dbe6 2005-02-13 devnull 	RSApriv *key;
 35 6e527fbc 2005-02-13 devnull 
 36 ce94dbe6 2005-02-13 devnull 	ret = -1;
 37 ce94dbe6 2005-02-13 devnull 	txt = nil;
 38 ce94dbe6 2005-02-13 devnull 	m = nil;
 39 ce94dbe6 2005-02-13 devnull 	mm = nil;
 40 ce94dbe6 2005-02-13 devnull 
 41 ce94dbe6 2005-02-13 devnull 	/* fetch key */
 42 ce94dbe6 2005-02-13 devnull 	c->state = "keylookup";
 43 6e527fbc 2005-02-13 devnull 	k = keylookup("%A", c->attr);
 44 6e527fbc 2005-02-13 devnull 	if(k == nil)
 45 ce94dbe6 2005-02-13 devnull 		goto out;
 46 ce94dbe6 2005-02-13 devnull 	key = k->priv;
 47 fa325e9b 2020-01-10 cross 
 48 ce94dbe6 2005-02-13 devnull 	/* make sure have private half if needed */
 49 ce94dbe6 2005-02-13 devnull 	role = strfindattr(c->attr, "role");
 50 ce94dbe6 2005-02-13 devnull 	if(strcmp(role, "decrypt") == 0 && !key->c2){
 51 ce94dbe6 2005-02-13 devnull 		werrstr("missing private half of key -- cannot decrypt");
 52 ce94dbe6 2005-02-13 devnull 		goto out;
 53 6e527fbc 2005-02-13 devnull 	}
 54 fa325e9b 2020-01-10 cross 
 55 ce94dbe6 2005-02-13 devnull 	/* read text */
 56 ce94dbe6 2005-02-13 devnull 	c->state = "read";
 57 ce94dbe6 2005-02-13 devnull 	if((n=convreadm(c, &txt)) < 0)
 58 ce94dbe6 2005-02-13 devnull 		goto out;
 59 ce94dbe6 2005-02-13 devnull 	if(n < 32){
 60 ce94dbe6 2005-02-13 devnull 		convprint(c, "data too short");
 61 ce94dbe6 2005-02-13 devnull 		goto out;
 62 6e527fbc 2005-02-13 devnull 	}
 63 fa325e9b 2020-01-10 cross 
 64 ce94dbe6 2005-02-13 devnull 	/* encrypt/decrypt */
 65 1f8a8072 2005-03-15 devnull 	m = betomp((uchar*)txt, n, nil);
 66 6e527fbc 2005-02-13 devnull 	if(m == nil)
 67 ce94dbe6 2005-02-13 devnull 		goto out;
 68 ce94dbe6 2005-02-13 devnull 	if(strcmp(role, "decrypt") == 0)
 69 e1a22963 2005-02-13 devnull 		mm = rsadecrypt(key, m, nil);
 70 ce94dbe6 2005-02-13 devnull 	else
 71 ce94dbe6 2005-02-13 devnull 		mm = rsaencrypt(&key->pub, m, nil);
 72 ce94dbe6 2005-02-13 devnull 	if(mm == nil)
 73 ce94dbe6 2005-02-13 devnull 		goto out;
 74 1f8a8072 2005-03-15 devnull 	n = mptobe(mm, (uchar*)buf, sizeof buf, nil);
 75 fa325e9b 2020-01-10 cross 
 76 ce94dbe6 2005-02-13 devnull 	/* send response */
 77 ce94dbe6 2005-02-13 devnull 	c->state = "write";
 78 ce94dbe6 2005-02-13 devnull 	convwrite(c, buf, n);
 79 ce94dbe6 2005-02-13 devnull 	ret = 0;
 80 ce94dbe6 2005-02-13 devnull 
 81 ce94dbe6 2005-02-13 devnull out:
 82 6e527fbc 2005-02-13 devnull 	mpfree(m);
 83 ce94dbe6 2005-02-13 devnull 	mpfree(mm);
 84 6e527fbc 2005-02-13 devnull 	keyclose(k);
 85 ce94dbe6 2005-02-13 devnull 	free(txt);
 86 ce94dbe6 2005-02-13 devnull 	return ret;
 87 6e527fbc 2005-02-13 devnull }
 88 6e527fbc 2005-02-13 devnull 
 89 6e527fbc 2005-02-13 devnull static int
 90 6e527fbc 2005-02-13 devnull xrsasign(Conv *c)
 91 6e527fbc 2005-02-13 devnull {
 92 ce94dbe6 2005-02-13 devnull 	char *hash, *role;
 93 ce94dbe6 2005-02-13 devnull 	int dlen, n, ret;
 94 6e527fbc 2005-02-13 devnull 	DigestAlg *hashfn;
 95 6e527fbc 2005-02-13 devnull 	Key *k;
 96 ce94dbe6 2005-02-13 devnull 	RSApriv *key;
 97 6e527fbc 2005-02-13 devnull 	uchar sig[1024], digest[64];
 98 ce94dbe6 2005-02-13 devnull 	char *sig2;
 99 6e527fbc 2005-02-13 devnull 
100 ce94dbe6 2005-02-13 devnull 	ret = -1;
101 fa325e9b 2020-01-10 cross 
102 ce94dbe6 2005-02-13 devnull 	/* fetch key */
103 ce94dbe6 2005-02-13 devnull 	c->state = "keylookup";
104 6e527fbc 2005-02-13 devnull 	k = keylookup("%A", c->attr);
105 6e527fbc 2005-02-13 devnull 	if(k == nil)
106 ce94dbe6 2005-02-13 devnull 		goto out;
107 ce94dbe6 2005-02-13 devnull 
108 ce94dbe6 2005-02-13 devnull 	/* make sure have private half if needed */
109 ce94dbe6 2005-02-13 devnull 	key = k->priv;
110 ce94dbe6 2005-02-13 devnull 	role = strfindattr(c->attr, "role");
111 ce94dbe6 2005-02-13 devnull 	if(strcmp(role, "sign") == 0 && !key->c2){
112 ce94dbe6 2005-02-13 devnull 		werrstr("missing private half of key -- cannot sign");
113 ce94dbe6 2005-02-13 devnull 		goto out;
114 ce94dbe6 2005-02-13 devnull 	}
115 fa325e9b 2020-01-10 cross 
116 ce94dbe6 2005-02-13 devnull 	/* get hash type from key */
117 6e527fbc 2005-02-13 devnull 	hash = strfindattr(k->attr, "hash");
118 6e527fbc 2005-02-13 devnull 	if(hash == nil)
119 6e527fbc 2005-02-13 devnull 		hash = "sha1";
120 6e527fbc 2005-02-13 devnull 	if(strcmp(hash, "sha1") == 0){
121 6e527fbc 2005-02-13 devnull 		hashfn = sha1;
122 6e527fbc 2005-02-13 devnull 		dlen = SHA1dlen;
123 6e527fbc 2005-02-13 devnull 	}else if(strcmp(hash, "md5") == 0){
124 6e527fbc 2005-02-13 devnull 		hashfn = md5;
125 6e527fbc 2005-02-13 devnull 		dlen = MD5dlen;
126 6e527fbc 2005-02-13 devnull 	}else{
127 6e527fbc 2005-02-13 devnull 		werrstr("unknown hash function %s", hash);
128 ce94dbe6 2005-02-13 devnull 		goto out;
129 6e527fbc 2005-02-13 devnull 	}
130 ce94dbe6 2005-02-13 devnull 
131 ce94dbe6 2005-02-13 devnull 	/* read hash */
132 ce94dbe6 2005-02-13 devnull 	c->state = "read hash";
133 ce94dbe6 2005-02-13 devnull 	if((n=convread(c, digest, dlen)) < 0)
134 ce94dbe6 2005-02-13 devnull 		goto out;
135 ce94dbe6 2005-02-13 devnull 
136 ce94dbe6 2005-02-13 devnull 	if(strcmp(role, "sign") == 0){
137 ce94dbe6 2005-02-13 devnull 		/* sign */
138 ce94dbe6 2005-02-13 devnull 		if((n=rsasign(key, hashfn, digest, dlen, sig, sizeof sig)) < 0)
139 ce94dbe6 2005-02-13 devnull 			goto out;
140 ce94dbe6 2005-02-13 devnull 
141 ce94dbe6 2005-02-13 devnull 		/* write */
142 ce94dbe6 2005-02-13 devnull 		convwrite(c, sig, n);
143 ce94dbe6 2005-02-13 devnull 	}else{
144 ce94dbe6 2005-02-13 devnull 		/* read signature */
145 ce94dbe6 2005-02-13 devnull 		if((n = convreadm(c, &sig2)) < 0)
146 ce94dbe6 2005-02-13 devnull 			goto out;
147 fa325e9b 2020-01-10 cross 
148 ce94dbe6 2005-02-13 devnull 		/* verify */
149 ce94dbe6 2005-02-13 devnull 		if(rsaverify(&key->pub, hashfn, digest, dlen, (uchar*)sig2, n) == 0)
150 ce94dbe6 2005-02-13 devnull 			convprint(c, "ok");
151 ce94dbe6 2005-02-13 devnull 		else
152 ce94dbe6 2005-02-13 devnull 			convprint(c, "signature does not verify");
153 ce94dbe6 2005-02-13 devnull 		free(sig2);
154 6e527fbc 2005-02-13 devnull 	}
155 ce94dbe6 2005-02-13 devnull 	ret = 0;
156 ce94dbe6 2005-02-13 devnull 
157 ce94dbe6 2005-02-13 devnull out:
158 6e527fbc 2005-02-13 devnull 	keyclose(k);
159 ce94dbe6 2005-02-13 devnull 	return ret;
160 6e527fbc 2005-02-13 devnull }
161 6e527fbc 2005-02-13 devnull 
162 6e527fbc 2005-02-13 devnull /*
163 fa325e9b 2020-01-10 cross  * convert to canonical form (lower case)
164 6e527fbc 2005-02-13 devnull  * for use in attribute matches.
165 6e527fbc 2005-02-13 devnull  */
166 6e527fbc 2005-02-13 devnull static void
167 6e527fbc 2005-02-13 devnull strlwr(char *a)
168 6e527fbc 2005-02-13 devnull {
169 6e527fbc 2005-02-13 devnull 	for(; *a; a++){
170 6e527fbc 2005-02-13 devnull 		if('A' <= *a && *a <= 'Z')
171 6e527fbc 2005-02-13 devnull 			*a += 'a' - 'A';
172 6e527fbc 2005-02-13 devnull 	}
173 6e527fbc 2005-02-13 devnull }
174 6e527fbc 2005-02-13 devnull 
175 6e527fbc 2005-02-13 devnull static RSApriv*
176 6e527fbc 2005-02-13 devnull readrsapriv(Key *k)
177 6e527fbc 2005-02-13 devnull {
178 6e527fbc 2005-02-13 devnull 	char *a;
179 6e527fbc 2005-02-13 devnull 	RSApriv *priv;
180 6e527fbc 2005-02-13 devnull 
181 6e527fbc 2005-02-13 devnull 	priv = rsaprivalloc();
182 6e527fbc 2005-02-13 devnull 
183 fa325e9b 2020-01-10 cross 	if((a=strfindattr(k->attr, "ek"))==nil
184 6e527fbc 2005-02-13 devnull 	|| (priv->pub.ek=strtomp(a, nil, 16, nil))==nil)
185 6e527fbc 2005-02-13 devnull 		goto Error;
186 6e527fbc 2005-02-13 devnull 	strlwr(a);
187 fa325e9b 2020-01-10 cross 	if((a=strfindattr(k->attr, "n"))==nil
188 6e527fbc 2005-02-13 devnull 	|| (priv->pub.n=strtomp(a, nil, 16, nil))==nil)
189 6e527fbc 2005-02-13 devnull 		goto Error;
190 6e527fbc 2005-02-13 devnull 	strlwr(a);
191 ce94dbe6 2005-02-13 devnull 	if(k->privattr == nil)	/* only public half */
192 ce94dbe6 2005-02-13 devnull 		return priv;
193 ce94dbe6 2005-02-13 devnull 
194 fa325e9b 2020-01-10 cross 	if((a=strfindattr(k->privattr, "!p"))==nil
195 6e527fbc 2005-02-13 devnull 	|| (priv->p=strtomp(a, nil, 16, nil))==nil)
196 6e527fbc 2005-02-13 devnull 		goto Error;
197 6e527fbc 2005-02-13 devnull 	strlwr(a);
198 fa325e9b 2020-01-10 cross 	if((a=strfindattr(k->privattr, "!q"))==nil
199 6e527fbc 2005-02-13 devnull 	|| (priv->q=strtomp(a, nil, 16, nil))==nil)
200 6e527fbc 2005-02-13 devnull 		goto Error;
201 6e527fbc 2005-02-13 devnull 	strlwr(a);
202 ddfc031c 2010-03-12 rsc 	if(!probably_prime(priv->p, 20) || !probably_prime(priv->q, 20)) {
203 ddfc031c 2010-03-12 rsc 		werrstr("rsa: p or q not prime");
204 ddfc031c 2010-03-12 rsc 		goto Error;
205 ddfc031c 2010-03-12 rsc 	}
206 fa325e9b 2020-01-10 cross 	if((a=strfindattr(k->privattr, "!kp"))==nil
207 6e527fbc 2005-02-13 devnull 	|| (priv->kp=strtomp(a, nil, 16, nil))==nil)
208 6e527fbc 2005-02-13 devnull 		goto Error;
209 6e527fbc 2005-02-13 devnull 	strlwr(a);
210 fa325e9b 2020-01-10 cross 	if((a=strfindattr(k->privattr, "!kq"))==nil
211 6e527fbc 2005-02-13 devnull 	|| (priv->kq=strtomp(a, nil, 16, nil))==nil)
212 6e527fbc 2005-02-13 devnull 		goto Error;
213 6e527fbc 2005-02-13 devnull 	strlwr(a);
214 fa325e9b 2020-01-10 cross 	if((a=strfindattr(k->privattr, "!c2"))==nil
215 6e527fbc 2005-02-13 devnull 	|| (priv->c2=strtomp(a, nil, 16, nil))==nil)
216 6e527fbc 2005-02-13 devnull 		goto Error;
217 6e527fbc 2005-02-13 devnull 	strlwr(a);
218 fa325e9b 2020-01-10 cross 	if((a=strfindattr(k->privattr, "!dk"))==nil
219 6e527fbc 2005-02-13 devnull 	|| (priv->dk=strtomp(a, nil, 16, nil))==nil)
220 6e527fbc 2005-02-13 devnull 		goto Error;
221 6e527fbc 2005-02-13 devnull 	strlwr(a);
222 6e527fbc 2005-02-13 devnull 	return priv;
223 6e527fbc 2005-02-13 devnull 
224 6e527fbc 2005-02-13 devnull Error:
225 6e527fbc 2005-02-13 devnull 	rsaprivfree(priv);
226 6e527fbc 2005-02-13 devnull 	return nil;
227 6e527fbc 2005-02-13 devnull }
228 6e527fbc 2005-02-13 devnull 
229 6e527fbc 2005-02-13 devnull static int
230 6e527fbc 2005-02-13 devnull rsacheck(Key *k)
231 6e527fbc 2005-02-13 devnull {
232 6e527fbc 2005-02-13 devnull 	static int first = 1;
233 fa325e9b 2020-01-10 cross 
234 6e527fbc 2005-02-13 devnull 	if(first){
235 6e527fbc 2005-02-13 devnull 		fmtinstall('B', mpfmt);
236 6e527fbc 2005-02-13 devnull 		first = 0;
237 6e527fbc 2005-02-13 devnull 	}
238 6e527fbc 2005-02-13 devnull 
239 6e527fbc 2005-02-13 devnull 	if((k->priv = readrsapriv(k)) == nil){
240 6e527fbc 2005-02-13 devnull 		werrstr("malformed key data");
241 6e527fbc 2005-02-13 devnull 		return -1;
242 6e527fbc 2005-02-13 devnull 	}
243 6e527fbc 2005-02-13 devnull 	return 0;
244 6e527fbc 2005-02-13 devnull }
245 6e527fbc 2005-02-13 devnull 
246 6e527fbc 2005-02-13 devnull static void
247 6e527fbc 2005-02-13 devnull rsaclose(Key *k)
248 6e527fbc 2005-02-13 devnull {
249 6e527fbc 2005-02-13 devnull 	rsaprivfree(k->priv);
250 6e527fbc 2005-02-13 devnull 	k->priv = nil;
251 6e527fbc 2005-02-13 devnull }
252 6e527fbc 2005-02-13 devnull 
253 6e527fbc 2005-02-13 devnull static Role
254 fa325e9b 2020-01-10 cross rsaroles[] =
255 6e527fbc 2005-02-13 devnull {
256 6e527fbc 2005-02-13 devnull 	"sign",	xrsasign,
257 ce94dbe6 2005-02-13 devnull 	"verify",	xrsasign,	/* public operation */
258 ce94dbe6 2005-02-13 devnull 	"decrypt",	xrsadecrypt,
259 ce94dbe6 2005-02-13 devnull 	"encrypt",	xrsadecrypt,	/* public operation */
260 6e527fbc 2005-02-13 devnull 	0
261 6e527fbc 2005-02-13 devnull };
262 6e527fbc 2005-02-13 devnull 
263 6e527fbc 2005-02-13 devnull Proto rsa = {
264 6e527fbc 2005-02-13 devnull 	"rsa",
265 6e527fbc 2005-02-13 devnull 	rsaroles,
266 6e527fbc 2005-02-13 devnull 	nil,
267 6e527fbc 2005-02-13 devnull 	rsacheck,
268 6e527fbc 2005-02-13 devnull 	rsaclose
269 6e527fbc 2005-02-13 devnull };