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#include "ssh.h"
static int
authrsafn(Conn *c)
{
uchar chalbuf[32+SESSIDLEN], response[MD5dlen];
char *s, *p;
int afd, ret;
AuthRpc *rpc;
Msg *m;
mpint *chal, *decr, *unpad, *mod;
debug(DBG_AUTH, "rsa!\n");
if((afd = open("/mnt/factotum/rpc", ORDWR)) < 0){
debug(DBG_AUTH, "open /mnt/factotum/rpc: %r\n");
return -1;
}
if((rpc = auth_allocrpc(afd)) == nil){
debug(DBG_AUTH, "auth_allocrpc: %r\n");
close(afd);
return -1;
}
s = "proto=rsa role=client";
if(auth_rpc(rpc, "start", s, strlen(s)) != ARok){
debug(DBG_AUTH, "auth_rpc start %s failed: %r\n", s);
auth_freerpc(rpc);
close(afd);
return -1;
}
ret = -1;
debug(DBG_AUTH, "trying factotum rsa keys\n");
while(auth_rpc(rpc, "read", nil, 0) == ARok){
debug(DBG_AUTH, "try %s\n", (char*)rpc->arg);
mod = strtomp(rpc->arg, nil, 16, nil);
m = allocmsg(c, SSH_CMSG_AUTH_RSA, 16+(mpsignif(mod)+7/8));
putmpint(m, mod);
sendmsg(m);
mpfree(mod);
m = recvmsg(c, -1);
switch(m->type){
case SSH_SMSG_FAILURE:
debug(DBG_AUTH, "\tnot accepted %s\n", (char*)rpc->arg);
free(m);
continue;
default:
badmsg(m, 0);
case SSH_SMSG_AUTH_RSA_CHALLENGE:
break;
}
chal = getmpint(m);
debug(DBG_AUTH, "\tgot challenge %B\n", chal);
free(m);
p = mptoa(chal, 16, nil, 0);
mpfree(chal);
if(p == nil){
debug(DBG_AUTH, "\tmptoa failed: %r\n");
unpad = mpnew(0);
goto Keepgoing;
}
if(auth_rpc(rpc, "write", p, strlen(p)) != ARok){
debug(DBG_AUTH, "\tauth_rpc write failed: %r\n");
free(p);
unpad = mpnew(0); /* it will fail, we'll go round again */
goto Keepgoing;
}
free(p);
if(auth_rpc(rpc, "read", nil, 0) != ARok){
debug(DBG_AUTH, "\tauth_rpc read failed: %r\n");
unpad = mpnew(0);
goto Keepgoing;
}
decr = strtomp(rpc->arg, nil, 16, nil);
debug(DBG_AUTH, "\tdecrypted %B\n", decr);
unpad = rsaunpad(decr);
debug(DBG_AUTH, "\tunpadded %B\n", unpad);
mpfree(decr);
Keepgoing:
mptoberjust(unpad, chalbuf, 32);
mpfree(unpad);
debug(DBG_AUTH, "\trjusted %.*H\n", 32, chalbuf);
memmove(chalbuf+32, c->sessid, SESSIDLEN);
debug(DBG_AUTH, "\tappend sesskey %.*H\n", 32, chalbuf);
md5(chalbuf, 32+SESSIDLEN, response, nil);
m = allocmsg(c, SSH_CMSG_AUTH_RSA_RESPONSE, MD5dlen);
putbytes(m, response, MD5dlen);
sendmsg(m);
m = recvmsg(c, -1);
switch(m->type){
case SSH_SMSG_FAILURE:
free(m);
continue;
default:
badmsg(m, 0);
case SSH_SMSG_SUCCESS:
break;
}
ret = 0;
break;
}
auth_freerpc(rpc);
close(afd);
return ret;
}
Auth authrsa =
{
SSH_AUTH_RSA,
"rsa",
authrsafn,
};
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