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#include <u.h>
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#include <libc.h>
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#include <mp.h>
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#include <fcall.h>
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#include <thread.h>
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#include <9p.h>
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#include <libsec.h>
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#include <ip.h>
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#include "netssh.h"
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extern Cipher *cryptos[];
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Packet *
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new_packet(Conn *c)
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{
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	Packet *p;
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	p = emalloc9p(sizeof(Packet));
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	init_packet(p);
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	p->c = c;
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	return p;
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}
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void
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init_packet(Packet *p)
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{
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	memset(p, 0, sizeof(Packet));
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	p->rlength = 1;
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}
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void
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add_byte(Packet *p, char c)
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{
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	p->payload[p->rlength-1] = c;
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	p->rlength++;
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}
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38 
void
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add_uint32(Packet *p, ulong l)
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{
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	hnputl(p->payload+p->rlength-1, l);
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	p->rlength += 4;
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}
44 
 
45 
ulong
46 
get_uint32(Packet *, uchar **data)
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{
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	ulong x;
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	x = nhgetl(*data);
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	*data += 4;
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	return x;
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}
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54 
int
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add_packet(Packet *p, void *data, int len)
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{
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	if(p->rlength + len > Maxpayload)
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		return -1;
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	memmove(p->payload + p->rlength - 1, data, len);
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	p->rlength += len;
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	return 0;
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}
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void
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add_block(Packet *p, void *data, int len)
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{
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	hnputl(p->payload + p->rlength - 1, len);
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	p->rlength += 4;
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	add_packet(p, data, len);
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}
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void
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add_string(Packet *p, char *s)
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{
75 
	uchar *q;
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	int n;
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	uchar nn[4];
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79 
	n = strlen(s);
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	hnputl(nn, n);
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	q = p->payload + p->rlength - 1;
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	memmove(q, nn, 4);
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	memmove(q+4, s, n);
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	p->rlength += n + 4;
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}
86 
 
87 
uchar *
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get_string(Packet *p, uchar *q, char *s, int lim, int *len)
89 
{
90 
	int n, m;
91 
 
92 
	if (p && q > p->payload + p->rlength)
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		s[0] = '\0';
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	m = nhgetl(q);
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	q += 4;
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	if(m < lim)
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		n = m;
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	else
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		n = lim - 1;
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	memmove(s, q, n);
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	s[n] = '\0';
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	q += m;
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	if(len)
104 
		*len = n;
105 
	return q;
106 
}
107 
 
108 
void
109 
add_mp(Packet *p, mpint *x)
110 
{
111 
	uchar *q;
112 
	int n;
113 
 
114 
	q = p->payload + p->rlength - 1;
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	n = mptobe(x, q + 4, Maxpktpay - p->rlength + 1 - 4, nil);
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	if(q[4] & 0x80){
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		memmove(q + 5, q + 4, n);
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		q[4] = 0;
119 
		n++;
120 
	}
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	hnputl(q, n);
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	p->rlength += n + 4;
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}
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125 
mpint *
126 
get_mp(uchar *q)
127 
{
128 
	return betomp(q + 4, nhgetl(q), nil);
129 
}
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131 
int
132 
finish_packet(Packet *p)
133 
{
134 
	Conn *c;
135 
	uchar *q, *buf;
136 
	int blklen, i, n2, n1, maclen;
137 
 
138 
	c = p->c;
139 
	blklen = 8;
140 
	if(c && debug > 1)
141 
		fprint(2, "%s: in finish_packet: enc %d outmac %d len %ld\n",
142 
			argv0, c->encrypt, c->outmac, p->rlength);
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	if(c && c->encrypt != -1){
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		blklen = cryptos[c->encrypt]->blklen;
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		if(blklen < 8)
146 
			blklen = 8;
147 
	}
148 
	n1 = p->rlength - 1;
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	n2 = blklen - (n1 + 5) % blklen;
150 
	if(n2 < 4)
151 
		n2 += blklen;
152 
	p->pad_len = n2;
153 
	for(i = 0, q = p->payload + n1; i < n2; ++i, ++q)
154 
		*q = fastrand();
155 
	p->rlength = n1 + n2 + 1;
156 
	hnputl(p->nlength, p->rlength);
157 
	maclen = 0;
158 
	if(c && c->outmac != -1){
159 
		maclen = SHA1dlen;
160 
		buf = emalloc9p(Maxpktpay);
161 
		hnputl(buf, c->outseq);
162 
		memmove(buf + 4, p->nlength, p->rlength + 4);
163 
		hmac_sha1(buf, p->rlength + 8, c->outik, maclen, q, nil);
164 
		free(buf);
165 
	}
166 
	if(c && c->encrypt != -1)
167 
		cryptos[c->encrypt]->encrypt(c->enccs, p->nlength, p->rlength + 4);
168 
	if (c)
169 
		c->outseq++;
170 
	if(debug > 1)
171 
		fprint(2, "%s: leaving finish packet: len %ld n1 %d n2 %d maclen %d\n",
172 
			argv0, p->rlength, n1, n2, maclen);
173 
	return p->rlength + 4 + maclen;
174 
}
175 
 
176 
/*
177 
 * The first blklen bytes are already decrypted so we could find the
178 
 * length.
179 
 */
180 
int
181 
undo_packet(Packet *p)
182 
{
183 
	Conn *c;
184 
	long nlength;
185 
	int nb;
186 
	uchar rmac[SHA1dlen], *buf;
187 
 
188 
	c = p->c;
189 
	nb = 4;
190 
	if(c->decrypt != -1)
191 
		nb = cryptos[c->decrypt]->blklen;
192 
	if(c->inmac != -1)
193 
		p->rlength -= SHA1dlen;			/* was magic 20 */
194 
	nlength = nhgetl(p->nlength);
195 
	if(c->decrypt != -1)
196 
		cryptos[c->decrypt]->decrypt(c->deccs, p->nlength + nb,
197 
			p->rlength + 4 - nb);
198 
	if(c->inmac != -1){
199 
		buf = emalloc9p(Maxpktpay);
200 
		hnputl(buf, c->inseq);
201 
		memmove(buf + 4, p->nlength, nlength + 4);
202 
		hmac_sha1(buf, nlength + 8, c->inik, SHA1dlen, rmac, nil);
203 
		free(buf);
204 
		if(memcmp(rmac, p->payload + nlength - 1, SHA1dlen) != 0){
205 
			fprint(2, "%s: received MAC verification failed: seq=%d\n",
206 
				argv0, c->inseq);
207 
			return -1;
208 
		}
209 
	}
210 
	c->inseq++;
211 
	p->rlength -= p->pad_len;
212 
	p->pad_len = 0;
213 
	return p->rlength - 1;
214 
}
215 
 
216 
void
217 
dump_packet(Packet *p)
218 
{
219 
	int i;
220 
	char *buf, *q, *e;
221 
 
222 
	fprint(2, "Length: %ld, Padding length: %d\n", p->rlength, p->pad_len);
223 
	q = buf = emalloc9p(Copybufsz);
224 
	e = buf + Copybufsz;
225 
	for(i = 0; i < p->rlength - 1; ++i){
226 
		q = seprint(q, e, " %02x", p->payload[i]);
227 
		if(i % 16 == 15)
228 
			q = seprint(q, e, "\n");
229 
		if(q - buf > Copybufsz - 4){
230 
			fprint(2, "%s", buf);
231 
			q = buf;
232 
		}
233 
	}
234 
	fprint(2, "%s\n", buf);
235 
	free(buf);
236 
}