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#include "ssh.h"
2 
 
3 
static int
4 
authrsafn(Conn *c)
5 
{
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	uchar chalbuf[32+SESSIDLEN], response[MD5dlen];
7 
	char *s, *p;
8 
	int afd, ret;
9 
	AuthRpc *rpc;
10 
	Msg *m;
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	mpint *chal, *decr, *unpad, *mod;
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13 
	debug(DBG_AUTH, "rsa!\n");
14 
 
15 
	if((afd = open("/mnt/factotum/rpc", ORDWR)) < 0){
16 
		debug(DBG_AUTH, "open /mnt/factotum/rpc: %r\n");
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		return -1;
18 
	}
19 
	if((rpc = auth_allocrpc(afd)) == nil){
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		debug(DBG_AUTH, "auth_allocrpc: %r\n");
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		close(afd);
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		return -1;
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	}
24 
	s = "proto=rsa role=client";
25 
	if(auth_rpc(rpc, "start", s, strlen(s)) != ARok){
26 
		debug(DBG_AUTH, "auth_rpc start %s failed: %r\n", s);
27 
		auth_freerpc(rpc);
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		close(afd);
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		return -1;
30 
	}
31 
 
32 
	ret = -1;
33 
	debug(DBG_AUTH, "trying factotum rsa keys\n");
34 
	while(auth_rpc(rpc, "read", nil, 0) == ARok){
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		debug(DBG_AUTH, "try %s\n", (char*)rpc->arg);
36 
		mod = strtomp(rpc->arg, nil, 16, nil);
37 
		m = allocmsg(c, SSH_CMSG_AUTH_RSA, 16+(mpsignif(mod)+7/8));
38 
		putmpint(m, mod);
39 
		sendmsg(m);
40 
		mpfree(mod);
41 
		m = recvmsg(c, -1);
42 
		switch(m->type){
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		case SSH_SMSG_FAILURE:
44 
			debug(DBG_AUTH, "\tnot accepted %s\n", (char*)rpc->arg);
45 
			free(m);
46 
			continue;
47 
		default:
48 
			badmsg(m, 0);
49 
		case SSH_SMSG_AUTH_RSA_CHALLENGE:
50 
			break;
51 
		}
52 
		chal = getmpint(m);
53 
		debug(DBG_AUTH, "\tgot challenge %B\n", chal);
54 
		free(m);
55 
		p = mptoa(chal, 16, nil, 0);
56 
		mpfree(chal);
57 
		if(p == nil){
58 
			debug(DBG_AUTH, "\tmptoa failed: %r\n");
59 
			unpad = mpnew(0);
60 
			goto Keepgoing;
61 
		}
62 
		if(auth_rpc(rpc, "write", p, strlen(p)) != ARok){
63 
			debug(DBG_AUTH, "\tauth_rpc write failed: %r\n");
64 
			free(p);
65 
			unpad = mpnew(0);	/* it will fail, we'll go round again */
66 
			goto Keepgoing;
67 
		}
68 
		free(p);
69 
		if(auth_rpc(rpc, "read", nil, 0) != ARok){
70 
			debug(DBG_AUTH, "\tauth_rpc read failed: %r\n");
71 
			unpad = mpnew(0);
72 
			goto Keepgoing;
73 
		}
74 
		decr = strtomp(rpc->arg, nil, 16, nil);
75 
		debug(DBG_AUTH, "\tdecrypted %B\n", decr);
76 
		unpad = rsaunpad(decr);
77 
		debug(DBG_AUTH, "\tunpadded %B\n", unpad);
78 
		mpfree(decr);
79 
	Keepgoing:
80 
		mptoberjust(unpad, chalbuf, 32);
81 
		mpfree(unpad);
82 
		debug(DBG_AUTH, "\trjusted %.*H\n", 32, chalbuf);
83 
		memmove(chalbuf+32, c->sessid, SESSIDLEN);
84 
		debug(DBG_AUTH, "\tappend sesskey %.*H\n", 32, chalbuf);
85 
		md5(chalbuf, 32+SESSIDLEN, response, nil);
86 
		m = allocmsg(c, SSH_CMSG_AUTH_RSA_RESPONSE, MD5dlen);
87 
		putbytes(m, response, MD5dlen);
88 
		sendmsg(m);
89 
 
90 
		m = recvmsg(c, -1);
91 
		switch(m->type){
92 
		case SSH_SMSG_FAILURE:
93 
			free(m);
94 
			continue;
95 
		default:
96 
			badmsg(m, 0);
97 
		case SSH_SMSG_SUCCESS:
98 
			break;
99 
		}
100 
		ret = 0;
101 
		break;
102 
	}
103 
	auth_freerpc(rpc);
104 
	close(afd);
105 
	return ret;
106 
}
107 
 
108 
Auth authrsa =
109 
{
110 
	SSH_AUTH_RSA,
111 
	"rsa",
112 
	authrsafn,
113 
};