1 a812ae4b 2004-12-27 devnull #include <u.h>
  2 a812ae4b 2004-12-27 devnull #include <libc.h>
  3 a812ae4b 2004-12-27 devnull #include <mp.h>
  4 a812ae4b 2004-12-27 devnull #include <libsec.h>
  5 a812ae4b 2004-12-27 devnull #include "SConn.h"
  6 a812ae4b 2004-12-27 devnull 
  7 a812ae4b 2004-12-27 devnull extern int verbose;
  8 a812ae4b 2004-12-27 devnull 
  9 a812ae4b 2004-12-27 devnull typedef struct ConnState {
 10 a812ae4b 2004-12-27 devnull 	uchar secret[SHA1dlen];
 11 a812ae4b 2004-12-27 devnull 	ulong seqno;
 12 a812ae4b 2004-12-27 devnull 	RC4state rc4;
 13 a812ae4b 2004-12-27 devnull } ConnState;
 14 a812ae4b 2004-12-27 devnull 
 15 a812ae4b 2004-12-27 devnull typedef struct SS{
 16 a812ae4b 2004-12-27 devnull 	int fd;		// file descriptor for read/write of encrypted data
 17 a812ae4b 2004-12-27 devnull 	int alg;	// if nonzero, "alg sha rc4_128"
 18 a812ae4b 2004-12-27 devnull 	ConnState in, out;
 19 a812ae4b 2004-12-27 devnull } SS;
 20 a812ae4b 2004-12-27 devnull 
 21 a812ae4b 2004-12-27 devnull static int
 22 a812ae4b 2004-12-27 devnull SC_secret(SConn *conn, uchar *sigma, int direction)
 23 a812ae4b 2004-12-27 devnull {
 24 a812ae4b 2004-12-27 devnull 	SS *ss = (SS*)(conn->chan);
 25 a812ae4b 2004-12-27 devnull 	int nsigma = conn->secretlen;
 26 a812ae4b 2004-12-27 devnull 
 27 a812ae4b 2004-12-27 devnull 	if(direction != 0){
 28 a812ae4b 2004-12-27 devnull 		hmac_sha1(sigma, nsigma, (uchar*)"one", 3, ss->out.secret, nil);
 29 a812ae4b 2004-12-27 devnull 		hmac_sha1(sigma, nsigma, (uchar*)"two", 3, ss->in.secret, nil);
 30 a812ae4b 2004-12-27 devnull 	}else{
 31 a812ae4b 2004-12-27 devnull 		hmac_sha1(sigma, nsigma, (uchar*)"two", 3, ss->out.secret, nil);
 32 a812ae4b 2004-12-27 devnull 		hmac_sha1(sigma, nsigma, (uchar*)"one", 3, ss->in.secret, nil);
 33 a812ae4b 2004-12-27 devnull 	}
 34 a812ae4b 2004-12-27 devnull 	setupRC4state(&ss->in.rc4, ss->in.secret, 16); // restrict to 128 bits
 35 a812ae4b 2004-12-27 devnull 	setupRC4state(&ss->out.rc4, ss->out.secret, 16);
 36 a812ae4b 2004-12-27 devnull 	ss->alg = 1;
 37 a812ae4b 2004-12-27 devnull 	return 0;
 38 a812ae4b 2004-12-27 devnull }
 39 a812ae4b 2004-12-27 devnull 
 40 a812ae4b 2004-12-27 devnull static void
 41 a812ae4b 2004-12-27 devnull hash(uchar secret[SHA1dlen], uchar *data, int len, int seqno, uchar d[SHA1dlen])
 42 a812ae4b 2004-12-27 devnull {
 43 a812ae4b 2004-12-27 devnull 	DigestState sha;
 44 a812ae4b 2004-12-27 devnull 	uchar seq[4];
 45 a812ae4b 2004-12-27 devnull 
 46 a812ae4b 2004-12-27 devnull 	seq[0] = seqno>>24;
 47 a812ae4b 2004-12-27 devnull 	seq[1] = seqno>>16;
 48 a812ae4b 2004-12-27 devnull 	seq[2] = seqno>>8;
 49 a812ae4b 2004-12-27 devnull 	seq[3] = seqno;
 50 a812ae4b 2004-12-27 devnull 	memset(&sha, 0, sizeof sha);
 51 a812ae4b 2004-12-27 devnull 	sha1(secret, SHA1dlen, nil, &sha);
 52 a812ae4b 2004-12-27 devnull 	sha1(data, len, nil, &sha);
 53 a812ae4b 2004-12-27 devnull 	sha1(seq, 4, d, &sha);
 54 a812ae4b 2004-12-27 devnull }
 55 a812ae4b 2004-12-27 devnull 
 56 a812ae4b 2004-12-27 devnull static int
 57 a812ae4b 2004-12-27 devnull verify(uchar secret[SHA1dlen], uchar *data, int len, int seqno, uchar d[SHA1dlen])
 58 a812ae4b 2004-12-27 devnull {
 59 a812ae4b 2004-12-27 devnull 	DigestState sha;
 60 a812ae4b 2004-12-27 devnull 	uchar seq[4];
 61 a812ae4b 2004-12-27 devnull 	uchar digest[SHA1dlen];
 62 a812ae4b 2004-12-27 devnull 
 63 a812ae4b 2004-12-27 devnull 	seq[0] = seqno>>24;
 64 a812ae4b 2004-12-27 devnull 	seq[1] = seqno>>16;
 65 a812ae4b 2004-12-27 devnull 	seq[2] = seqno>>8;
 66 a812ae4b 2004-12-27 devnull 	seq[3] = seqno;
 67 a812ae4b 2004-12-27 devnull 	memset(&sha, 0, sizeof sha);
 68 a812ae4b 2004-12-27 devnull 	sha1(secret, SHA1dlen, nil, &sha);
 69 a812ae4b 2004-12-27 devnull 	sha1(data, len, nil, &sha);
 70 a812ae4b 2004-12-27 devnull 	sha1(seq, 4, digest, &sha);
 71 a812ae4b 2004-12-27 devnull 	return memcmp(d, digest, SHA1dlen);
 72 a812ae4b 2004-12-27 devnull }
 73 a812ae4b 2004-12-27 devnull 
 74 a812ae4b 2004-12-27 devnull static int
 75 a812ae4b 2004-12-27 devnull SC_read(SConn *conn, uchar *buf, int n)
 76 a812ae4b 2004-12-27 devnull {
 77 a812ae4b 2004-12-27 devnull 	SS *ss = (SS*)(conn->chan);
 78 a812ae4b 2004-12-27 devnull 	uchar count[2], digest[SHA1dlen];
 79 a812ae4b 2004-12-27 devnull 	int len, nr;
 80 a812ae4b 2004-12-27 devnull 
 81 a812ae4b 2004-12-27 devnull 	if(read(ss->fd, count, 2) != 2 || (count[0]&0x80) == 0){
 82 a812ae4b 2004-12-27 devnull 		snprint((char*)buf,n,"!SC_read invalid count");
 83 a812ae4b 2004-12-27 devnull 		return -1;
 84 a812ae4b 2004-12-27 devnull 	}
 85 a812ae4b 2004-12-27 devnull 	len = (count[0]&0x7f)<<8 | count[1];	// SSL-style count; no pad
 86 a812ae4b 2004-12-27 devnull 	if(ss->alg){
 87 a812ae4b 2004-12-27 devnull 		len -= SHA1dlen;
 88 a812ae4b 2004-12-27 devnull 		if(len <= 0 || readn(ss->fd, digest, SHA1dlen) != SHA1dlen){
 89 a812ae4b 2004-12-27 devnull 			snprint((char*)buf,n,"!SC_read missing sha1");
 90 a812ae4b 2004-12-27 devnull 			return -1;
 91 a812ae4b 2004-12-27 devnull 		}
 92 a812ae4b 2004-12-27 devnull 		if(len > n || readn(ss->fd, buf, len) != len){
 93 a812ae4b 2004-12-27 devnull 			snprint((char*)buf,n,"!SC_read missing data");
 94 a812ae4b 2004-12-27 devnull 			return -1;
 95 a812ae4b 2004-12-27 devnull 		}
 96 a812ae4b 2004-12-27 devnull 		rc4(&ss->in.rc4, digest, SHA1dlen);
 97 a812ae4b 2004-12-27 devnull 		rc4(&ss->in.rc4, buf, len);
 98 a812ae4b 2004-12-27 devnull 		if(verify(ss->in.secret, buf, len, ss->in.seqno, digest) != 0){
 99 a812ae4b 2004-12-27 devnull 			snprint((char*)buf,n,"!SC_read integrity check failed");
100 a812ae4b 2004-12-27 devnull 			return -1;
101 a812ae4b 2004-12-27 devnull 		}
102 a812ae4b 2004-12-27 devnull 	}else{
103 a812ae4b 2004-12-27 devnull 		if(len <= 0 || len > n){
104 a812ae4b 2004-12-27 devnull 			snprint((char*)buf,n,"!SC_read implausible record length");
105 a812ae4b 2004-12-27 devnull 			return -1;
106 a812ae4b 2004-12-27 devnull 		}
107 a812ae4b 2004-12-27 devnull 		if( (nr = readn(ss->fd, buf, len)) != len){
108 a812ae4b 2004-12-27 devnull 			snprint((char*)buf,n,"!SC_read expected %d bytes, but got %d", len, nr);
109 a812ae4b 2004-12-27 devnull 			return -1;
110 a812ae4b 2004-12-27 devnull 		}
111 a812ae4b 2004-12-27 devnull 	}
112 a812ae4b 2004-12-27 devnull 	ss->in.seqno++;
113 a812ae4b 2004-12-27 devnull 	return len;
114 a812ae4b 2004-12-27 devnull }
115 a812ae4b 2004-12-27 devnull 
116 a812ae4b 2004-12-27 devnull static int
117 a812ae4b 2004-12-27 devnull SC_write(SConn *conn, uchar *buf, int n)
118 a812ae4b 2004-12-27 devnull {
119 a812ae4b 2004-12-27 devnull 	SS *ss = (SS*)(conn->chan);
120 a812ae4b 2004-12-27 devnull 	uchar count[2], digest[SHA1dlen], enc[Maxmsg+1];
121 a812ae4b 2004-12-27 devnull 	int len;
122 a812ae4b 2004-12-27 devnull 
123 a812ae4b 2004-12-27 devnull 	if(n <= 0 || n > Maxmsg+1){
124 a812ae4b 2004-12-27 devnull 		werrstr("!SC_write invalid n %d", n);
125 a812ae4b 2004-12-27 devnull 		return -1;
126 a812ae4b 2004-12-27 devnull 	}
127 a812ae4b 2004-12-27 devnull 	len = n;
128 a812ae4b 2004-12-27 devnull 	if(ss->alg)
129 a812ae4b 2004-12-27 devnull 		len += SHA1dlen;
130 a812ae4b 2004-12-27 devnull 	count[0] = 0x80 | len>>8;
131 a812ae4b 2004-12-27 devnull 	count[1] = len;
132 a812ae4b 2004-12-27 devnull 	if(write(ss->fd, count, 2) != 2){
133 a812ae4b 2004-12-27 devnull 		werrstr("!SC_write invalid count");
134 a812ae4b 2004-12-27 devnull 		return -1;
135 a812ae4b 2004-12-27 devnull 	}
136 a812ae4b 2004-12-27 devnull 	if(ss->alg){
137 a812ae4b 2004-12-27 devnull 		hash(ss->out.secret, buf, n, ss->out.seqno, digest);
138 a812ae4b 2004-12-27 devnull 		rc4(&ss->out.rc4, digest, SHA1dlen);
139 a812ae4b 2004-12-27 devnull 		memcpy(enc, buf, n);
140 a812ae4b 2004-12-27 devnull 		rc4(&ss->out.rc4, enc, n);
141 a812ae4b 2004-12-27 devnull 		if(write(ss->fd, digest, SHA1dlen) != SHA1dlen ||
142 a812ae4b 2004-12-27 devnull 				write(ss->fd, enc, n) != n){
143 a812ae4b 2004-12-27 devnull 			werrstr("!SC_write error on send");
144 a812ae4b 2004-12-27 devnull 			return -1;
145 a812ae4b 2004-12-27 devnull 		}
146 a812ae4b 2004-12-27 devnull 	}else{
147 a812ae4b 2004-12-27 devnull 		if(write(ss->fd, buf, n) != n){
148 a812ae4b 2004-12-27 devnull 			werrstr("!SC_write error on send");
149 a812ae4b 2004-12-27 devnull 			return -1;
150 a812ae4b 2004-12-27 devnull 		}
151 a812ae4b 2004-12-27 devnull 	}
152 a812ae4b 2004-12-27 devnull 	ss->out.seqno++;
153 a812ae4b 2004-12-27 devnull 	return n;
154 a812ae4b 2004-12-27 devnull }
155 a812ae4b 2004-12-27 devnull 
156 a812ae4b 2004-12-27 devnull static void
157 a812ae4b 2004-12-27 devnull SC_free(SConn *conn)
158 a812ae4b 2004-12-27 devnull {
159 a812ae4b 2004-12-27 devnull 	SS *ss = (SS*)(conn->chan);
160 a812ae4b 2004-12-27 devnull 
161 a812ae4b 2004-12-27 devnull 	close(ss->fd);
162 a812ae4b 2004-12-27 devnull 	free(ss);
163 a812ae4b 2004-12-27 devnull 	free(conn);
164 a812ae4b 2004-12-27 devnull }
165 a812ae4b 2004-12-27 devnull 
166 a812ae4b 2004-12-27 devnull SConn*
167 a812ae4b 2004-12-27 devnull newSConn(int fd)
168 a812ae4b 2004-12-27 devnull {
169 a812ae4b 2004-12-27 devnull 	SS *ss;
170 a812ae4b 2004-12-27 devnull 	SConn *conn;
171 a812ae4b 2004-12-27 devnull 
172 a812ae4b 2004-12-27 devnull 	if(fd < 0)
173 a812ae4b 2004-12-27 devnull 		return nil;
174 a812ae4b 2004-12-27 devnull 	ss = (SS*)emalloc(sizeof(*ss));
175 a812ae4b 2004-12-27 devnull 	conn = (SConn*)emalloc(sizeof(*conn));
176 a812ae4b 2004-12-27 devnull 	ss->fd  = fd;
177 a812ae4b 2004-12-27 devnull 	ss->alg = 0;
178 a812ae4b 2004-12-27 devnull 	conn->chan = (void*)ss;
179 a812ae4b 2004-12-27 devnull 	conn->secretlen = SHA1dlen;
180 a812ae4b 2004-12-27 devnull 	conn->free = SC_free;
181 a812ae4b 2004-12-27 devnull 	conn->secret = SC_secret;
182 a812ae4b 2004-12-27 devnull 	conn->read = SC_read;
183 a812ae4b 2004-12-27 devnull 	conn->write = SC_write;
184 a812ae4b 2004-12-27 devnull 	return conn;
185 a812ae4b 2004-12-27 devnull }
186 a812ae4b 2004-12-27 devnull 
187 a812ae4b 2004-12-27 devnull void
188 a812ae4b 2004-12-27 devnull writerr(SConn *conn, char *s)
189 a812ae4b 2004-12-27 devnull {
190 a812ae4b 2004-12-27 devnull 	char buf[Maxmsg];
191 a812ae4b 2004-12-27 devnull 
192 a812ae4b 2004-12-27 devnull 	snprint(buf, Maxmsg, "!%s", s);
193 a812ae4b 2004-12-27 devnull 	conn->write(conn, (uchar*)buf, strlen(buf));
194 a812ae4b 2004-12-27 devnull }
195 a812ae4b 2004-12-27 devnull 
196 a812ae4b 2004-12-27 devnull int
197 a812ae4b 2004-12-27 devnull readstr(SConn *conn, char *s)
198 a812ae4b 2004-12-27 devnull {
199 a812ae4b 2004-12-27 devnull 	int n;
200 a812ae4b 2004-12-27 devnull 
201 a812ae4b 2004-12-27 devnull 	n = conn->read(conn, (uchar*)s, Maxmsg);
202 a812ae4b 2004-12-27 devnull 	if(n >= 0){
203 a812ae4b 2004-12-27 devnull 		s[n] = 0;
204 a812ae4b 2004-12-27 devnull 		if(s[0] == '!'){
205 a812ae4b 2004-12-27 devnull 			memmove(s, s+1, n);
206 a812ae4b 2004-12-27 devnull 			n = -1;
207 a812ae4b 2004-12-27 devnull 		}
208 a812ae4b 2004-12-27 devnull 	}else{
209 a812ae4b 2004-12-27 devnull 		strcpy(s, "read error");
210 a812ae4b 2004-12-27 devnull 	}
211 a812ae4b 2004-12-27 devnull 	return n;
212 a812ae4b 2004-12-27 devnull }
213 a812ae4b 2004-12-27 devnull