#include <u.h>#include <libc.h>#include <mp.h>#include <libsec.h>#include <auth.h>#include <bio.h> voidusage(void){	fprint(2, "usage: dsasign [-i id] [-v] key <data\n");	exits("usage");} static void doverify(void);static char *getline(int*); char *id;Biobuf b;int nid;char *key; voidmain(int argc, char **argv){	int n, verify, afd;	char *text, *p;	uchar digest[SHA1dlen];	AuthRpc *rpc;	Fmt fmt;		fmtinstall('[', encodefmt);	fmtinstall('H', encodefmt);		verify = 0;	id = "";	ARGBEGIN{	case 'i':		id = EARGF(usage());		break;	case 'v':		verify = 1;		break;	default:		usage();	}ARGEND		if(argc != 1)		usage();	key = argv[0];	nid = strlen(id); 	Binit(&b, 0, OREAD);	if(verify) {		doverify();		exits(nil);	} 	if((afd = open("/mnt/factotum/rpc", ORDWR)) < 0)		sysfatal("open /mnt/factotum/rpc: %r"); 	if((rpc = auth_allocrpc(afd)) == nil){		fprint(2, "dsasign: auth_allocrpc: %r\n");		exits("rpc");	}	key = smprint("proto=dsa role=sign %s", key);	if(auth_rpc(rpc, "start", key, strlen(key)) != ARok){		fprint(2, "dsasign: auth 'start' failed: %r\n");		auth_freerpc(rpc);		exits("rpc");	}		print("+%s\n", id); 	Binit(&b, 0, OREAD);	fmtstrinit(&fmt);	while((p = getline(&n)) != nil) {		if(p[0] == '-' || p[0] == '+')			print("+");		print("%s\n", p);		fmtprint(&fmt, "%s\n", p);	}	text = fmtstrflush(&fmt);	sha1((uchar*)text, strlen(text), digest, nil); 	if(auth_rpc(rpc, "write", digest, SHA1dlen) != ARok)		sysfatal("auth write in sign failed: %r");	if(auth_rpc(rpc, "read", nil, 0) != ARok)		sysfatal("auth read in sign failed: %r"); 	print("-%s %.*H\n", id, rpc->narg, rpc->arg);	exits(nil);} static mpint*keytomp(Attr *a, char *name){	char *p;	mpint *m;		p = _strfindattr(a, name);	if(p == nil)		sysfatal("missing key attribute %s", name);	m = strtomp(p, nil, 16, nil);	if(m == nil)		sysfatal("malformed key attribute %s=%s", name, p);	return m;} static voiddoverify(void){	char *p, *text;	uchar digest[SHA1dlen], sig[1024];	int n;	Fmt fmt;	Attr *a;	DSAsig dsig;	DSApub dkey;		a = _parseattr(key);	if(a == nil)		sysfatal("invalid key");	dkey.alpha = keytomp(a, "alpha");	dkey.key = keytomp(a, "key");	dkey.p = keytomp(a, "p");	dkey.q = keytomp(a, "q");	if(!probably_prime(dkey.p, 20) && !probably_prime(dkey.q, 20))		sysfatal("p or q not prime"); 	while((p = getline(&n)) != nil)		if(p[0] == '+' && strcmp(p+1, id) == 0)			goto start;	sysfatal("no message found"); start:	fmtstrinit(&fmt);	while((p = getline(&n)) != nil) {		if(n >= 1+nid+1+16 && p[0] == '-' && strncmp(p+1, id, nid) == 0 && p[1+nid] == ' ')			goto end;		if(p[0] == '+')			p++;		fmtprint(&fmt, "%s\n", p);	}	sysfatal("did not find end of message"); end:	if(dec16(sig, sizeof sig, p+1+nid+1, n-(1+nid+1)) != 20+20)		sysfatal("malformed signture");	text = fmtstrflush(&fmt);	sha1((uchar*)text, strlen(text), digest, nil); 	dsig.r = betomp(sig, 20, nil);	dsig.s = betomp(sig+20, 20, nil); 	if(dsaverify(&dkey, &dsig, betomp(digest, sizeof digest, nil)) < 0)		sysfatal("signature failed to verify: %r");		write(1, text, strlen(text));	exits("");} static char*getline(int *np){	char *p;	int n;		if((p = Brdline(&b, '\n')) == nil)		return nil;	n = Blinelen(&b);	while(n > 0 && (p[n-1] == '\n' || p[n-1] == ' ' || p[n-1] == '\t'))		n--;	p[n] = '\0';	*np = n;	return p;}