1 2277c5d7 2004-03-21 devnull /*
  2 2277c5d7 2004-03-21 devnull  * SSH RSA authentication.
  3 2277c5d7 2004-03-21 devnull  * 
  4 2277c5d7 2004-03-21 devnull  * Client protocol:
  5 2277c5d7 2004-03-21 devnull  *	read public key
  6 2277c5d7 2004-03-21 devnull  *		if you don't like it, read another, repeat
  7 2277c5d7 2004-03-21 devnull  *	write challenge
  8 2277c5d7 2004-03-21 devnull  *	read response
  9 2277c5d7 2004-03-21 devnull  * all numbers are hexadecimal biginits parsable with strtomp.
 10 2277c5d7 2004-03-21 devnull  */
 11 2277c5d7 2004-03-21 devnull 
 12 2277c5d7 2004-03-21 devnull #include "dat.h"
 13 2277c5d7 2004-03-21 devnull 
 14 2277c5d7 2004-03-21 devnull enum {
 15 2277c5d7 2004-03-21 devnull 	CHavePub,
 16 2277c5d7 2004-03-21 devnull 	CHaveResp,
 17 2277c5d7 2004-03-21 devnull 
 18 2277c5d7 2004-03-21 devnull 	Maxphase,
 19 2277c5d7 2004-03-21 devnull };
 20 2277c5d7 2004-03-21 devnull 
 21 2277c5d7 2004-03-21 devnull static char *phasenames[] = {
 22 2277c5d7 2004-03-21 devnull [CHavePub]	"CHavePub",
 23 2277c5d7 2004-03-21 devnull [CHaveResp]	"CHaveResp",
 24 2277c5d7 2004-03-21 devnull };
 25 2277c5d7 2004-03-21 devnull 
 26 2277c5d7 2004-03-21 devnull struct State
 27 2277c5d7 2004-03-21 devnull {
 28 2277c5d7 2004-03-21 devnull 	RSApriv *priv;
 29 2277c5d7 2004-03-21 devnull 	mpint *resp;
 30 2277c5d7 2004-03-21 devnull 	int off;
 31 2277c5d7 2004-03-21 devnull 	Key *key;
 32 2277c5d7 2004-03-21 devnull };
 33 2277c5d7 2004-03-21 devnull 
 34 2277c5d7 2004-03-21 devnull static RSApriv*
 35 2277c5d7 2004-03-21 devnull readrsapriv(Key *k)
 36 2277c5d7 2004-03-21 devnull {
 37 2277c5d7 2004-03-21 devnull 	char *a;
 38 2277c5d7 2004-03-21 devnull 	RSApriv *priv;
 39 2277c5d7 2004-03-21 devnull 
 40 2277c5d7 2004-03-21 devnull 	priv = rsaprivalloc();
 41 2277c5d7 2004-03-21 devnull 
 42 2277c5d7 2004-03-21 devnull 	if((a=strfindattr(k->attr, "ek"))==nil || (priv->pub.ek=strtomp(a, nil, 16, nil))==nil)
 43 2277c5d7 2004-03-21 devnull 		goto Error;
 44 2277c5d7 2004-03-21 devnull 	if((a=strfindattr(k->attr, "n"))==nil || (priv->pub.n=strtomp(a, nil, 16, nil))==nil)
 45 2277c5d7 2004-03-21 devnull 		goto Error;
 46 2277c5d7 2004-03-21 devnull 	if((a=strfindattr(k->privattr, "!p"))==nil || (priv->p=strtomp(a, nil, 16, nil))==nil)
 47 2277c5d7 2004-03-21 devnull 		goto Error;
 48 2277c5d7 2004-03-21 devnull 	if((a=strfindattr(k->privattr, "!q"))==nil || (priv->q=strtomp(a, nil, 16, nil))==nil)
 49 2277c5d7 2004-03-21 devnull 		goto Error;
 50 2277c5d7 2004-03-21 devnull 	if((a=strfindattr(k->privattr, "!kp"))==nil || (priv->kp=strtomp(a, nil, 16, nil))==nil)
 51 2277c5d7 2004-03-21 devnull 		goto Error;
 52 2277c5d7 2004-03-21 devnull 	if((a=strfindattr(k->privattr, "!kq"))==nil || (priv->kq=strtomp(a, nil, 16, nil))==nil)
 53 2277c5d7 2004-03-21 devnull 		goto Error;
 54 2277c5d7 2004-03-21 devnull 	if((a=strfindattr(k->privattr, "!c2"))==nil || (priv->c2=strtomp(a, nil, 16, nil))==nil)
 55 2277c5d7 2004-03-21 devnull 		goto Error;
 56 2277c5d7 2004-03-21 devnull 	if((a=strfindattr(k->privattr, "!dk"))==nil || (priv->dk=strtomp(a, nil, 16, nil))==nil)
 57 2277c5d7 2004-03-21 devnull 		goto Error;
 58 2277c5d7 2004-03-21 devnull 	return priv;
 59 2277c5d7 2004-03-21 devnull 
 60 2277c5d7 2004-03-21 devnull Error:
 61 2277c5d7 2004-03-21 devnull 	rsaprivfree(priv);
 62 2277c5d7 2004-03-21 devnull 	return nil;
 63 2277c5d7 2004-03-21 devnull }
 64 2277c5d7 2004-03-21 devnull 
 65 2277c5d7 2004-03-21 devnull static int
 66 2277c5d7 2004-03-21 devnull sshrsainit(Proto*, Fsstate *fss)
 67 2277c5d7 2004-03-21 devnull {
 68 2277c5d7 2004-03-21 devnull 	int iscli;
 69 2277c5d7 2004-03-21 devnull 	State *s;
 70 2277c5d7 2004-03-21 devnull 
 71 2277c5d7 2004-03-21 devnull 	if((iscli = isclient(strfindattr(fss->attr, "role"))) < 0)
 72 2277c5d7 2004-03-21 devnull 		return failure(fss, nil);
 73 2277c5d7 2004-03-21 devnull 	if(iscli==0)
 74 2277c5d7 2004-03-21 devnull 		return failure(fss, "sshrsa server unimplemented");
 75 2277c5d7 2004-03-21 devnull 
 76 2277c5d7 2004-03-21 devnull 	s = emalloc(sizeof *s);
 77 2277c5d7 2004-03-21 devnull 	fss->phasename = phasenames;
 78 2277c5d7 2004-03-21 devnull 	fss->maxphase = Maxphase;
 79 2277c5d7 2004-03-21 devnull 	fss->phase = CHavePub;
 80 2277c5d7 2004-03-21 devnull 	fss->ps = s;
 81 2277c5d7 2004-03-21 devnull 	return RpcOk;
 82 2277c5d7 2004-03-21 devnull }
 83 2277c5d7 2004-03-21 devnull 
 84 2277c5d7 2004-03-21 devnull static int
 85 2277c5d7 2004-03-21 devnull sshrsaread(Fsstate *fss, void *va, uint *n)
 86 2277c5d7 2004-03-21 devnull {
 87 2277c5d7 2004-03-21 devnull 	RSApriv *priv;
 88 2277c5d7 2004-03-21 devnull 	State *s;
 89 2277c5d7 2004-03-21 devnull 
 90 2277c5d7 2004-03-21 devnull 	s = fss->ps;
 91 2277c5d7 2004-03-21 devnull 	switch(fss->phase){
 92 2277c5d7 2004-03-21 devnull 	default:
 93 2277c5d7 2004-03-21 devnull 		return phaseerror(fss, "read");
 94 2277c5d7 2004-03-21 devnull 	case CHavePub:
 95 2277c5d7 2004-03-21 devnull 		if(s->key){
 96 2277c5d7 2004-03-21 devnull 			closekey(s->key);
 97 2277c5d7 2004-03-21 devnull 			s->key = nil;
 98 2277c5d7 2004-03-21 devnull 		}
 99 2277c5d7 2004-03-21 devnull 		if((s->key = findkey(fss, Kuser, nil, s->off, fss->attr, nil)) == nil)
100 2277c5d7 2004-03-21 devnull 			return failure(fss, nil);
101 2277c5d7 2004-03-21 devnull 		s->off++;
102 2277c5d7 2004-03-21 devnull 		priv = s->key->priv;
103 2277c5d7 2004-03-21 devnull 		*n = snprint(va, *n, "%B", priv->pub.n);
104 2277c5d7 2004-03-21 devnull 		return RpcOk;
105 2277c5d7 2004-03-21 devnull 	case CHaveResp:
106 2277c5d7 2004-03-21 devnull 		*n = snprint(va, *n, "%B", s->resp);
107 2277c5d7 2004-03-21 devnull 		fss->phase = Established;
108 2277c5d7 2004-03-21 devnull 		return RpcOk;
109 2277c5d7 2004-03-21 devnull 	}
110 2277c5d7 2004-03-21 devnull }
111 2277c5d7 2004-03-21 devnull 
112 2277c5d7 2004-03-21 devnull static int
113 2277c5d7 2004-03-21 devnull sshrsawrite(Fsstate *fss, void *va, uint)
114 2277c5d7 2004-03-21 devnull {
115 2277c5d7 2004-03-21 devnull 	mpint *m;
116 2277c5d7 2004-03-21 devnull 	State *s;
117 2277c5d7 2004-03-21 devnull 
118 2277c5d7 2004-03-21 devnull 	s = fss->ps;
119 2277c5d7 2004-03-21 devnull 	switch(fss->phase){
120 2277c5d7 2004-03-21 devnull 	default:
121 2277c5d7 2004-03-21 devnull 		return phaseerror(fss, "write");
122 2277c5d7 2004-03-21 devnull 	case CHavePub:
123 2277c5d7 2004-03-21 devnull 		if(s->key == nil)
124 2277c5d7 2004-03-21 devnull 			return failure(fss, "no current key");
125 2277c5d7 2004-03-21 devnull 		m = strtomp(va, nil, 16, nil);
126 2277c5d7 2004-03-21 devnull 		m = rsadecrypt(s->key->priv, m, m);
127 2277c5d7 2004-03-21 devnull 		s->resp = m;
128 2277c5d7 2004-03-21 devnull 		fss->phase = CHaveResp;
129 2277c5d7 2004-03-21 devnull 		return RpcOk;
130 2277c5d7 2004-03-21 devnull 	}
131 2277c5d7 2004-03-21 devnull }
132 2277c5d7 2004-03-21 devnull 
133 2277c5d7 2004-03-21 devnull static void
134 2277c5d7 2004-03-21 devnull sshrsaclose(Fsstate *fss)
135 2277c5d7 2004-03-21 devnull {
136 2277c5d7 2004-03-21 devnull 	State *s;
137 2277c5d7 2004-03-21 devnull 
138 2277c5d7 2004-03-21 devnull 	s = fss->ps;
139 2277c5d7 2004-03-21 devnull 	if(s->key)
140 2277c5d7 2004-03-21 devnull 		closekey(s->key);
141 2277c5d7 2004-03-21 devnull 	if(s->resp)
142 2277c5d7 2004-03-21 devnull 		mpfree(s->resp);
143 2277c5d7 2004-03-21 devnull 	free(s);
144 2277c5d7 2004-03-21 devnull }
145 2277c5d7 2004-03-21 devnull 
146 2277c5d7 2004-03-21 devnull static int
147 2277c5d7 2004-03-21 devnull sshrsaaddkey(Key *k)
148 2277c5d7 2004-03-21 devnull {
149 2277c5d7 2004-03-21 devnull 	fmtinstall('B', mpconv);
150 2277c5d7 2004-03-21 devnull 
151 2277c5d7 2004-03-21 devnull 	if((k->priv = readrsapriv(k)) == nil){
152 2277c5d7 2004-03-21 devnull 		werrstr("malformed key data");
153 2277c5d7 2004-03-21 devnull 		return -1;
154 2277c5d7 2004-03-21 devnull 	}
155 2277c5d7 2004-03-21 devnull 	return replacekey(k);
156 2277c5d7 2004-03-21 devnull }
157 2277c5d7 2004-03-21 devnull 
158 2277c5d7 2004-03-21 devnull static void
159 2277c5d7 2004-03-21 devnull sshrsaclosekey(Key *k)
160 2277c5d7 2004-03-21 devnull {
161 2277c5d7 2004-03-21 devnull 	rsaprivfree(k->priv);
162 2277c5d7 2004-03-21 devnull }
163 2277c5d7 2004-03-21 devnull 
164 2277c5d7 2004-03-21 devnull Proto sshrsa = {
165 2277c5d7 2004-03-21 devnull .name=	"sshrsa",
166 2277c5d7 2004-03-21 devnull .init=		sshrsainit,
167 2277c5d7 2004-03-21 devnull .write=	sshrsawrite,
168 2277c5d7 2004-03-21 devnull .read=	sshrsaread,
169 2277c5d7 2004-03-21 devnull .close=	sshrsaclose,
170 2277c5d7 2004-03-21 devnull .addkey=	sshrsaaddkey,
171 2277c5d7 2004-03-21 devnull .closekey=	sshrsaclosekey,
172 2277c5d7 2004-03-21 devnull };