#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, 0); switch(m->type){ case SSH_SMSG_FAILURE: debug(DBG_AUTH, "\tnot accepted\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, 0); 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, };