/*  * This file is part of the UCB release of Plan 9. It is subject to the license * terms in the LICENSE file found in the top-level directory of this * distribution and at http://akaros.cs.berkeley.edu/files/Plan9License. No * part of the UCB release of Plan 9, including this file, may be copied, * modified, propagated, or distributed except according to the terms contained * in the LICENSE file. */ #include <u.h>#include <libc.h>#include <mp.h>#include <libsec.h>#include "SConn.h" extern int verbose; typedef struct ConnState {	uchar secret[SHA1dlen];	ulong seqno;	RC4state rc4;} ConnState; typedef struct SS{	int fd;		// file descriptor for read/write of encrypted data	int alg;	// if nonzero, "alg sha rc4_128"	ConnState in, out;} SS; static intSC_secret(SConn *conn, uchar *sigma, int direction){	SS *ss = (SS*)(conn->chan);	int nsigma = conn->secretlen; 	if(direction != 0){		hmac_sha1(sigma, nsigma, (uchar*)"one", 3, ss->out.secret, nil);		hmac_sha1(sigma, nsigma, (uchar*)"two", 3, ss->in.secret, nil);	}else{		hmac_sha1(sigma, nsigma, (uchar*)"two", 3, ss->out.secret, nil);		hmac_sha1(sigma, nsigma, (uchar*)"one", 3, ss->in.secret, nil);	}	setupRC4state(&ss->in.rc4, ss->in.secret, 16); // restrict to 128 bits	setupRC4state(&ss->out.rc4, ss->out.secret, 16);	ss->alg = 1;	return 0;} static voidhash(uchar secret[SHA1dlen], uchar *data, int len, int seqno, uchar d[SHA1dlen]){	DigestState sha;	uchar seq[4]; 	seq[0] = seqno>>24;	seq[1] = seqno>>16;	seq[2] = seqno>>8;	seq[3] = seqno;	memset(&sha, 0, sizeof sha);	sha1(secret, SHA1dlen, nil, &sha);	sha1(data, len, nil, &sha);	sha1(seq, 4, d, &sha);} static intverify(uchar secret[SHA1dlen], uchar *data, int len, int seqno, uchar d[SHA1dlen]){	DigestState sha;	uchar seq[4];	uchar digest[SHA1dlen]; 	seq[0] = seqno>>24;	seq[1] = seqno>>16;	seq[2] = seqno>>8;	seq[3] = seqno;	memset(&sha, 0, sizeof sha);	sha1(secret, SHA1dlen, nil, &sha);	sha1(data, len, nil, &sha);	sha1(seq, 4, digest, &sha);	return memcmp(d, digest, SHA1dlen);} static intSC_read(SConn *conn, uchar *buf, int n){	SS *ss = (SS*)(conn->chan);	uchar count[2], digest[SHA1dlen];	int len, nr; 	if(read(ss->fd, count, 2) != 2 || (count[0]&0x80) == 0){		snprint((char*)buf,n,"!SC_read invalid count");		return -1;	}	len = (count[0]&0x7f)<<8 | count[1];	// SSL-style count; no pad	if(ss->alg){		len -= SHA1dlen;		if(len <= 0 || readn(ss->fd, digest, SHA1dlen) != SHA1dlen){			snprint((char*)buf,n,"!SC_read missing sha1");			return -1;		}		if(len > n || readn(ss->fd, buf, len) != len){			snprint((char*)buf,n,"!SC_read missing data");			return -1;		}		rc4(&ss->in.rc4, digest, SHA1dlen);		rc4(&ss->in.rc4, buf, len);		if(verify(ss->in.secret, buf, len, ss->in.seqno, digest) != 0){			snprint((char*)buf,n,"!SC_read integrity check failed");			return -1;		}	}else{		if(len <= 0 || len > n){			snprint((char*)buf,n,"!SC_read implausible record length");			return -1;		}		if( (nr = readn(ss->fd, buf, len)) != len){			snprint((char*)buf,n,"!SC_read expected %d bytes, but got %d", len, nr);			return -1;		}	}	ss->in.seqno++;	return len;} static intSC_write(SConn *conn, uchar *buf, int n){	SS *ss = (SS*)(conn->chan);	uchar count[2], digest[SHA1dlen], enc[Maxmsg+1];	int len; 	if(n <= 0 || n > Maxmsg+1){		werrstr("!SC_write invalid n %d", n);		return -1;	}	len = n;	if(ss->alg)		len += SHA1dlen;	count[0] = 0x80 | len>>8;	count[1] = len;	if(write(ss->fd, count, 2) != 2){		werrstr("!SC_write invalid count");		return -1;	}	if(ss->alg){		hash(ss->out.secret, buf, n, ss->out.seqno, digest);		rc4(&ss->out.rc4, digest, SHA1dlen);		memcpy(enc, buf, n);		rc4(&ss->out.rc4, enc, n);		if(write(ss->fd, digest, SHA1dlen) != SHA1dlen ||				write(ss->fd, enc, n) != n){			werrstr("!SC_write error on send");			return -1;		}	}else{		if(write(ss->fd, buf, n) != n){			werrstr("!SC_write error on send");			return -1;		}	}	ss->out.seqno++;	return n;} static voidSC_free(SConn *conn){	SS *ss = (SS*)(conn->chan); 	close(ss->fd);	free(ss);	free(conn);} SConn*newSConn(int fd){	SS *ss;	SConn *conn; 	if(fd < 0)		return nil;	ss = (SS*)emalloc(sizeof(*ss));	conn = (SConn*)emalloc(sizeof(*conn));	ss->fd  = fd;	ss->alg = 0;	conn->chan = (void*)ss;	conn->secretlen = SHA1dlen;	conn->free = SC_free;	conn->secret = SC_secret;	conn->read = SC_read;	conn->write = SC_write;	return conn;} voidwriterr(SConn *conn, char *s){	char buf[Maxmsg]; 	snprint(buf, Maxmsg, "!%s", s);	conn->write(conn, (uchar*)buf, strlen(buf));} intreadstr(SConn *conn, char *s){	int n; 	n = conn->read(conn, (uchar*)s, Maxmsg);	if(n >= 0){		s[n] = 0;		if(s[0] == '!'){			memmove(s, s+1, n);			n = -1;		}	}else{		strcpy(s, "connection read error");	}	return n;}