cpu: cleanup ssl code, make sure -p works for any auth method

sys/src/cmd/cpu.c

@@ -24,7 +24,7 @@ void	writestr(int, char*, char*, int);
 int	readstr(int, char*, int);
 char	*rexcall(int*, char*, char*);
 int	setamalg(char*);
-char *keyspec = "";
+char	*keyspec = "";
 
 int 	notechan;
 int	exportpid;
@@ -43,6 +43,11 @@ char	*ealgs = "rc4_256 sha1";
 /* message size for exportfs; may be larger so we can do big graphics in CPU window */
 int	msgsize = Maxfdata+IOHDRSZ;
 
+/* encryption mechanisms */
+static int	clear(int);
+
+int (*encryption)(int) = clear;
+
 /* authentication mechanisms */
 static int	netkeyauth(int);
 static int	netkeysrvauth(int, char*);
@@ -56,8 +61,7 @@ struct AuthMethod {
 	char	*name;			/* name of method */
 	int	(*cf)(int);		/* client side authentication */
 	int	(*sf)(int, char*);	/* server side authentication */
-} authmethod[] =
+} authmethod[] = {
-{
 	{ "p9",		p9auth,		srvp9auth,},
 	{ "netkey",	netkeyauth,	netkeysrvauth,},
 	{ "none",	noauth,		srvnoauth,},
@@ -73,7 +77,7 @@ char	*aan = "/bin/aan";
 char	*anstring = "tcp!*!0";
 char	*filterp = nil;
 
-int	filter(int fd, char *host);
+int filter(int fd, char *host);
 
 void
 usage(void)
@@ -360,9 +364,12 @@ remoteside(int old)
 	} else
 		writestr(fd, "", "", 1);
 
-	fd = (*am->sf)(fd, user);
+	if((fd = (*am->sf)(fd, user)) < 0)
-	if(fd < 0)
 		fatal("srvauth: %r");
+	if((fd = filter(fd, nil)) < 0)
+		fatal("filter: %r");
+	if((fd = encryption(fd)) < 0)
+		fatal("encrypt: %r");
 
 	/* Now collect invoking cpu's current directory or possibly a command */
 	gotcmd = 0;
@@ -466,10 +473,13 @@ rexcall(int *fd, char *host, char *service)
 
 	/* authenticate */
 	procsetname("%s: auth via %s", origargs, am->name);
-	*fd = (*am->cf)(*fd);
+	if((*fd = (*am->cf)(*fd)) < 0)
-	if(*fd < 0)
 		return "can't authenticate";
-	return 0;
+	if((*fd = filter(*fd, system)) < 0)
+		return "can't filter";
+	if((*fd = encryption(*fd)) < 0)
+		return "can't encrypt";
+	return nil;
 }
 
 void
@@ -540,7 +550,7 @@ netkeyauth(int fd)
 		if(readstr(fd, chall, sizeof chall) < 0)
 			break;
 		if(*chall == 0)
-			return filter(fd, system);
+			return fd;
 		print("challenge: %s\nresponse: ", chall);
 		if(readln(resp, sizeof(resp)) < 0)
 			break;
@@ -580,7 +590,21 @@ netkeysrvauth(int fd, char *user)
 	if(auth_chuid(ai, 0) < 0)
 		fatal("newns: %r");
 	auth_freeAI(ai);
-	return filter(fd, nil);
+	return fd;
+}
+
+static int
+clear(int fd)
+{
+	return fd;
+}
+
+static char sslsecret[2][21];
+
+static int
+sslencrypt(int fd)
+{
+	return pushssl(fd, ealgs, sslsecret[0], sslsecret[1], nil);
 }
 
 static void
@@ -590,55 +614,63 @@ mksecret(char *t, uchar *f)
 		f[0], f[1], f[2], f[3], f[4], f[5], f[6], f[7], f[8], f[9]);
 }
 
+static int
+sslsetup(int fd, uchar *secret, int nsecret, int isclient)
+{
+	uchar key[16], digest[SHA1dlen];
+	int i;
+
+	if(ealgs == nil)
+		return fd;
+
+	if(nsecret < 8){
+		werrstr("secret too small to ssl");
+		return -1;
+	}
+	memmove(key+4, secret, 8);
+
+	/* exchange random numbers */
+	srand(truerand());
+
+	if(isclient){
+		for(i = 0; i < 4; i++)
+			key[i] = rand();
+		if(write(fd, key, 4) != 4)
+			return -1;
+		if(readn(fd, key+12, 4) != 4)
+			return -1;
+	} else {
+		for(i = 0; i < 4; i++)
+			key[i+12] = rand();
+		if(readn(fd, key, 4) != 4)
+			return -1;
+		if(write(fd, key+12, 4) != 4)
+			return -1;
+	}
+
+	/* scramble into two secrets */
+	sha1(key, sizeof(key), digest, nil);
+	mksecret(sslsecret[isclient == 0], digest);
+	mksecret(sslsecret[isclient != 0], digest+10);
+
+	encryption = sslencrypt;
+
+	return fd;
+}
+
 /*
  *  plan9 authentication followed by rc4 encryption
  */
 static int
 p9auth(int fd)
 {
-	uchar key[16], digest[SHA1dlen];
-	char fromclientsecret[21];
-	char fromserversecret[21];
 	AuthInfo *ai;
-	int i;
 
-	procsetname("%s: auth_proxy proto=%q role=client %s",
-		origargs, p9authproto, keyspec);
 	ai = auth_proxy(fd, auth_getkey, "proto=%q role=client %s", p9authproto, keyspec);
 	if(ai == nil)
 		return -1;
-	if(ealgs == nil){
+	fd = sslsetup(fd, ai->secret, ai->nsecret, 1);
-		auth_freeAI(ai);
-		return fd;
-	}
-	assert(ai->nsecret <= sizeof(key)-4);
-	memmove(key+4, ai->secret, ai->nsecret);
 	auth_freeAI(ai);
-
-	/* exchange random numbers */
-	srand(truerand());
-	for(i = 0; i < 4; i++)
-		key[i] = rand();
-	procsetname("writing p9 key");
-	if(write(fd, key, 4) != 4)
-		return -1;
-	procsetname("reading p9 key");
-	if(readn(fd, key+12, 4) != 4)
-		return -1;
-
-	/* scramble into two secrets */
-	sha1(key, sizeof(key), digest, nil);
-	mksecret(fromclientsecret, digest);
-	mksecret(fromserversecret, digest+10);
-
-	if((fd = filter(fd, system)) < 0)
-		return -1;
-
-	/* set up encryption */
-	procsetname("pushssl");
-	fd = pushssl(fd, ealgs, fromclientsecret, fromserversecret, nil);
-	if(fd < 0)
-		werrstr("can't establish ssl connection: %r");
 	return fd;
 }
 
@@ -658,25 +690,10 @@ srvnoauth(int fd, char *user)
 	return fd;
 }
 
-void
-loghex(uchar *p, int n)
-{
-	char buf[100];
-	int i;
-
-	for(i = 0; i < n; i++)
-		sprint(buf+2*i, "%2.2ux", p[i]);
-	syslog(0, "cpu", "%s", buf);
-}
-
 static int
 srvp9auth(int fd, char *user)
 {
-	uchar key[16], digest[SHA1dlen];
-	char fromclientsecret[21];
-	char fromserversecret[21];
 	AuthInfo *ai;
-	int i;
 
 	ai = auth_proxy(fd, nil, "proto=%q role=server %s", p9authproto, keyspec);
 	if(ai == nil)
@@ -684,35 +701,8 @@ srvp9auth(int fd, char *user)
 	if(auth_chuid(ai, nil) < 0)
 		fatal("newns: %r");
 	snprint(user, MaxStr, "%s", ai->cuid);
-	if(ealgs == nil){
+	fd = sslsetup(fd, ai->secret, ai->nsecret, 0);
-		auth_freeAI(ai);
-		return fd;
-	}
-	assert(ai->nsecret <= sizeof(key)-4);
-	memmove(key+4, ai->secret, ai->nsecret);
 	auth_freeAI(ai);
-
-	/* exchange random numbers */
-	srand(truerand());
-	for(i = 0; i < 4; i++)
-		key[i+12] = rand();
-	if(readn(fd, key, 4) != 4)
-		return -1;
-	if(write(fd, key+12, 4) != 4)
-		return -1;
-
-	/* scramble into two secrets */
-	sha1(key, sizeof(key), digest, nil);
-	mksecret(fromclientsecret, digest);
-	mksecret(fromserversecret, digest+10);
-
-	if((fd = filter(fd, nil)) < 0)
-		return -1;
-
-	/* set up encryption */
-	fd = pushssl(fd, ealgs, fromserversecret, fromclientsecret, nil);
-	if(fd < 0)
-		werrstr("can't establish ssl connection: %r");
 	return fd;
 }