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  * DSA signing and verification
  6 fa325e9b 2020-01-10 cross  *
  7 6e527fbc 2005-02-13 devnull  * Sign:
  8 6e527fbc 2005-02-13 devnull  *	start p=xxx q=xxx alpha=xxx key=xxx
  9 6e527fbc 2005-02-13 devnull  *	write msg
 10 6e527fbc 2005-02-13 devnull  *	read signature(msg)
 11 6e527fbc 2005-02-13 devnull  *
 12 6e527fbc 2005-02-13 devnull  * Verify: (not implemented)
 13 6e527fbc 2005-02-13 devnull  *	start p=xxx q=xxx alpha=xxx key=xxx
 14 6e527fbc 2005-02-13 devnull  *	write msg
 15 6e527fbc 2005-02-13 devnull  *	write signature(msg)
 16 6e527fbc 2005-02-13 devnull  *	read ok or fail
 17 fa325e9b 2020-01-10 cross  *
 18 6e527fbc 2005-02-13 devnull  * all numbers are hexadecimal bigints parsable with strtomp.
 19 6e527fbc 2005-02-13 devnull  */
 20 fa325e9b 2020-01-10 cross 
 21 6e527fbc 2005-02-13 devnull static int
 22 6e527fbc 2005-02-13 devnull xdsasign(Conv *c)
 23 6e527fbc 2005-02-13 devnull {
 24 6e527fbc 2005-02-13 devnull 	int n;
 25 6e527fbc 2005-02-13 devnull 	mpint *m;
 26 ce94dbe6 2005-02-13 devnull 	uchar digest[SHA1dlen], sigblob[20+20];
 27 6e527fbc 2005-02-13 devnull 	DSAsig *sig;
 28 6e527fbc 2005-02-13 devnull 	Key *k;
 29 6e527fbc 2005-02-13 devnull 
 30 6e527fbc 2005-02-13 devnull 	k = keylookup("%A", c->attr);
 31 6e527fbc 2005-02-13 devnull 	if(k == nil)
 32 6e527fbc 2005-02-13 devnull 		return -1;
 33 6e527fbc 2005-02-13 devnull 
 34 6e527fbc 2005-02-13 devnull 	c->state = "read data";
 35 6e527fbc 2005-02-13 devnull 	if((n=convread(c, digest, SHA1dlen)) < 0){
 36 6e527fbc 2005-02-13 devnull 		keyclose(k);
 37 6e527fbc 2005-02-13 devnull 		return -1;
 38 6e527fbc 2005-02-13 devnull 	}
 39 6e527fbc 2005-02-13 devnull 	m = betomp(digest, SHA1dlen, nil);
 40 6e527fbc 2005-02-13 devnull 	if(m == nil){
 41 6e527fbc 2005-02-13 devnull 		keyclose(k);
 42 6e527fbc 2005-02-13 devnull 		return -1;
 43 6e527fbc 2005-02-13 devnull 	}
 44 6e527fbc 2005-02-13 devnull 	sig = dsasign(k->priv, m);
 45 6e527fbc 2005-02-13 devnull 	keyclose(k);
 46 6e527fbc 2005-02-13 devnull 	mpfree(m);
 47 6e527fbc 2005-02-13 devnull 	if(sig == nil)
 48 6e527fbc 2005-02-13 devnull 		return -1;
 49 ce94dbe6 2005-02-13 devnull 	if(mpsignif(sig->r) > 20*8 || mpsignif(sig->s) > 20*8){
 50 ce94dbe6 2005-02-13 devnull 		werrstr("signature too long");
 51 ce94dbe6 2005-02-13 devnull 		return -1;
 52 ce94dbe6 2005-02-13 devnull 	}
 53 ce94dbe6 2005-02-13 devnull 	mptoberjust(sig->r, sigblob, 20);
 54 ce94dbe6 2005-02-13 devnull 	mptoberjust(sig->s, sigblob+20, 20);
 55 ce94dbe6 2005-02-13 devnull 	convwrite(c, sigblob, sizeof sigblob);
 56 6e527fbc 2005-02-13 devnull 	dsasigfree(sig);
 57 6e527fbc 2005-02-13 devnull 	return 0;
 58 6e527fbc 2005-02-13 devnull }
 59 6e527fbc 2005-02-13 devnull 
 60 6e527fbc 2005-02-13 devnull /*
 61 fa325e9b 2020-01-10 cross  * convert to canonical form (lower case)
 62 6e527fbc 2005-02-13 devnull  * for use in attribute matches.
 63 6e527fbc 2005-02-13 devnull  */
 64 6e527fbc 2005-02-13 devnull static void
 65 6e527fbc 2005-02-13 devnull strlwr(char *a)
 66 6e527fbc 2005-02-13 devnull {
 67 6e527fbc 2005-02-13 devnull 	for(; *a; a++){
 68 6e527fbc 2005-02-13 devnull 		if('A' <= *a && *a <= 'Z')
 69 6e527fbc 2005-02-13 devnull 			*a += 'a' - 'A';
 70 6e527fbc 2005-02-13 devnull 	}
 71 6e527fbc 2005-02-13 devnull }
 72 6e527fbc 2005-02-13 devnull 
 73 6e527fbc 2005-02-13 devnull static DSApriv*
 74 6e527fbc 2005-02-13 devnull readdsapriv(Key *k)
 75 6e527fbc 2005-02-13 devnull {
 76 6e527fbc 2005-02-13 devnull 	char *a;
 77 6e527fbc 2005-02-13 devnull 	DSApriv *priv;
 78 6e527fbc 2005-02-13 devnull 
 79 6e527fbc 2005-02-13 devnull 	priv = dsaprivalloc();
 80 6e527fbc 2005-02-13 devnull 
 81 fa325e9b 2020-01-10 cross 	if((a=strfindattr(k->attr, "p"))==nil
 82 6e527fbc 2005-02-13 devnull 	|| (priv->pub.p=strtomp(a, nil, 16, nil))==nil)
 83 6e527fbc 2005-02-13 devnull 		goto Error;
 84 6e527fbc 2005-02-13 devnull 	strlwr(a);
 85 fa325e9b 2020-01-10 cross 	if((a=strfindattr(k->attr, "q"))==nil
 86 6e527fbc 2005-02-13 devnull 	|| (priv->pub.q=strtomp(a, nil, 16, nil))==nil)
 87 6e527fbc 2005-02-13 devnull 		goto Error;
 88 6e527fbc 2005-02-13 devnull 	strlwr(a);
 89 ddfc031c 2010-03-12 rsc 	if(!probably_prime(priv->pub.p, 20) && !probably_prime(priv->pub.q, 20)) {
 90 ddfc031c 2010-03-12 rsc 		werrstr("dsa: p or q not prime");
 91 ddfc031c 2010-03-12 rsc 		goto Error;
 92 ddfc031c 2010-03-12 rsc 	}
 93 fa325e9b 2020-01-10 cross 	if((a=strfindattr(k->attr, "alpha"))==nil
 94 6e527fbc 2005-02-13 devnull 	|| (priv->pub.alpha=strtomp(a, nil, 16, nil))==nil)
 95 6e527fbc 2005-02-13 devnull 		goto Error;
 96 6e527fbc 2005-02-13 devnull 	strlwr(a);
 97 fa325e9b 2020-01-10 cross 	if((a=strfindattr(k->attr, "key"))==nil
 98 6e527fbc 2005-02-13 devnull 	|| (priv->pub.key=strtomp(a, nil, 16, nil))==nil)
 99 6e527fbc 2005-02-13 devnull 		goto Error;
100 6e527fbc 2005-02-13 devnull 	strlwr(a);
101 fa325e9b 2020-01-10 cross 	if((a=strfindattr(k->privattr, "!secret"))==nil
102 6e527fbc 2005-02-13 devnull 	|| (priv->secret=strtomp(a, nil, 16, nil))==nil)
103 6e527fbc 2005-02-13 devnull 		goto Error;
104 6e527fbc 2005-02-13 devnull 	strlwr(a);
105 6e527fbc 2005-02-13 devnull 	return priv;
106 6e527fbc 2005-02-13 devnull 
107 6e527fbc 2005-02-13 devnull Error:
108 6e527fbc 2005-02-13 devnull 	dsaprivfree(priv);
109 6e527fbc 2005-02-13 devnull 	return nil;
110 6e527fbc 2005-02-13 devnull }
111 6e527fbc 2005-02-13 devnull 
112 6e527fbc 2005-02-13 devnull static int
113 6e527fbc 2005-02-13 devnull dsacheck(Key *k)
114 6e527fbc 2005-02-13 devnull {
115 6e527fbc 2005-02-13 devnull 	static int first = 1;
116 fa325e9b 2020-01-10 cross 
117 6e527fbc 2005-02-13 devnull 	if(first){
118 6e527fbc 2005-02-13 devnull 		fmtinstall('B', mpfmt);
119 6e527fbc 2005-02-13 devnull 		first = 0;
120 6e527fbc 2005-02-13 devnull 	}
121 6e527fbc 2005-02-13 devnull 
122 6e527fbc 2005-02-13 devnull 	if((k->priv = readdsapriv(k)) == nil){
123 6e527fbc 2005-02-13 devnull 		werrstr("malformed key data");
124 6e527fbc 2005-02-13 devnull 		return -1;
125 6e527fbc 2005-02-13 devnull 	}
126 6e527fbc 2005-02-13 devnull 	return 0;
127 6e527fbc 2005-02-13 devnull }
128 6e527fbc 2005-02-13 devnull 
129 6e527fbc 2005-02-13 devnull static void
130 6e527fbc 2005-02-13 devnull dsaclose(Key *k)
131 6e527fbc 2005-02-13 devnull {
132 6e527fbc 2005-02-13 devnull 	dsaprivfree(k->priv);
133 6e527fbc 2005-02-13 devnull 	k->priv = nil;
134 6e527fbc 2005-02-13 devnull }
135 6e527fbc 2005-02-13 devnull 
136 6e527fbc 2005-02-13 devnull static Role
137 fa325e9b 2020-01-10 cross dsaroles[] =
138 6e527fbc 2005-02-13 devnull {
139 6e527fbc 2005-02-13 devnull 	"sign",	xdsasign,
140 6e527fbc 2005-02-13 devnull 	0
141 6e527fbc 2005-02-13 devnull };
142 6e527fbc 2005-02-13 devnull 
143 6e527fbc 2005-02-13 devnull Proto dsa = {
144 6e527fbc 2005-02-13 devnull 	"dsa",
145 6e527fbc 2005-02-13 devnull 	dsaroles,
146 6e527fbc 2005-02-13 devnull 	nil,
147 6e527fbc 2005-02-13 devnull 	dsacheck,
148 6e527fbc 2005-02-13 devnull 	dsaclose
149 6e527fbc 2005-02-13 devnull };