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// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
// vim: ts=8 sw=2 smarttab
/*
* Ceph - scalable distributed file system
*
* Copyright (C) 2004-2009 Sage Weil <sage@newdream.net>
*
* This is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License version 2.1, as published by the Free Software
* Foundation. See file COPYING.
*
*/
#include "CephxSessionHandler.h"
#include "CephxProtocol.h"
#include <errno.h>
#include <sstream>
#include "common/config.h"
#include "include/ceph_features.h"
#include "msg/Message.h"
#define dout_subsys ceph_subsys_auth
namespace {
#ifdef WITH_SEASTAR
crimson::common::ConfigProxy& conf(CephContext*) {
return crimson::common::local_conf();
}
#else
ConfigProxy& conf(CephContext* cct) {
return cct->_conf;
}
#endif
}
int CephxSessionHandler::_calc_signature(Message *m, uint64_t *psig)
{
const ceph_msg_header& header = m->get_header();
const ceph_msg_footer& footer = m->get_footer();
if (!HAVE_FEATURE(features, CEPHX_V2)) {
// legacy pre-mimic behavior for compatibility
// optimized signature calculation
// - avoid temporary allocated buffers from encode_encrypt[_enc_bl]
// - skip the leading 4 byte wrapper from encode_encrypt
struct {
__u8 v;
ceph_le64 magic;
ceph_le32 len;
ceph_le32 header_crc;
ceph_le32 front_crc;
ceph_le32 middle_crc;
ceph_le32 data_crc;
} __attribute__ ((packed)) sigblock = {
1, ceph_le64(AUTH_ENC_MAGIC), ceph_le32(4 * 4),
ceph_le32(header.crc), ceph_le32(footer.front_crc),
ceph_le32(footer.middle_crc), ceph_le32(footer.data_crc)
};
char exp_buf[CryptoKey::get_max_outbuf_size(sizeof(sigblock))];
try {
const CryptoKey::in_slice_t in {
sizeof(sigblock),
reinterpret_cast<const unsigned char*>(&sigblock)
};
const CryptoKey::out_slice_t out {
sizeof(exp_buf),
reinterpret_cast<unsigned char*>(&exp_buf)
};
key.encrypt(cct, in, out);
} catch (std::exception& e) {
lderr(cct) << __func__ << " failed to encrypt signature block" << dendl;
return -1;
}
*psig = *reinterpret_cast<ceph_le64*>(exp_buf);
} else {
// newer mimic+ signatures
struct {
ceph_le32 header_crc;
ceph_le32 front_crc;
ceph_le32 front_len;
ceph_le32 middle_crc;
ceph_le32 middle_len;
ceph_le32 data_crc;
ceph_le32 data_len;
ceph_le32 seq_lower_word;
} __attribute__ ((packed)) sigblock = {
ceph_le32(header.crc),
ceph_le32(footer.front_crc),
ceph_le32(header.front_len),
ceph_le32(footer.middle_crc),
ceph_le32(header.middle_len),
ceph_le32(footer.data_crc),
ceph_le32(header.data_len),
ceph_le32(header.seq)
};
char exp_buf[CryptoKey::get_max_outbuf_size(sizeof(sigblock))];
try {
const CryptoKey::in_slice_t in {
sizeof(sigblock),
reinterpret_cast<const unsigned char*>(&sigblock)
};
const CryptoKey::out_slice_t out {
sizeof(exp_buf),
reinterpret_cast<unsigned char*>(&exp_buf)
};
key.encrypt(cct, in, out);
} catch (std::exception& e) {
lderr(cct) << __func__ << " failed to encrypt signature block" << dendl;
return -1;
}
struct enc {
ceph_le64 a, b, c, d;
} *penc = reinterpret_cast<enc*>(exp_buf);
*psig = penc->a ^ penc->b ^ penc->c ^ penc->d;
}
ldout(cct, 10) << __func__ << " seq " << m->get_seq()
<< " front_crc_ = " << footer.front_crc
<< " middle_crc = " << footer.middle_crc
<< " data_crc = " << footer.data_crc
<< " sig = " << *psig
<< dendl;
return 0;
}
int CephxSessionHandler::sign_message(Message *m)
{
// If runtime signing option is off, just return success without signing.
if (!conf(cct)->cephx_sign_messages) {
return 0;
}
uint64_t sig;
int r = _calc_signature(m, &sig);
if (r < 0)
return r;
ceph_msg_footer& f = m->get_footer();
f.sig = sig;
f.flags = (unsigned)f.flags | CEPH_MSG_FOOTER_SIGNED;
ldout(cct, 20) << "Putting signature in client message(seq # " << m->get_seq()
<< "): sig = " << sig << dendl;
return 0;
}
int CephxSessionHandler::check_message_signature(Message *m)
{
// If runtime signing option is off, just return success without checking signature.
if (!conf(cct)->cephx_sign_messages) {
return 0;
}
if ((features & CEPH_FEATURE_MSG_AUTH) == 0) {
// it's fine, we didn't negotiate this feature.
return 0;
}
uint64_t sig;
int r = _calc_signature(m, &sig);
if (r < 0)
return r;
if (sig != m->get_footer().sig) {
// Should have been signed, but signature check failed. PLR
if (!(m->get_footer().flags & CEPH_MSG_FOOTER_SIGNED)) {
ldout(cct, 0) << "SIGN: MSG " << m->get_seq() << " Sender did not set CEPH_MSG_FOOTER_SIGNED." << dendl;
}
ldout(cct, 0) << "SIGN: MSG " << m->get_seq() << " Message signature does not match contents." << dendl;
ldout(cct, 0) << "SIGN: MSG " << m->get_seq() << "Signature on message:" << dendl;
ldout(cct, 0) << "SIGN: MSG " << m->get_seq() << " sig: " << m->get_footer().sig << dendl;
ldout(cct, 0) << "SIGN: MSG " << m->get_seq() << "Locally calculated signature:" << dendl;
ldout(cct, 0) << "SIGN: MSG " << m->get_seq() << " sig_check:" << sig << dendl;
// For the moment, printing an error message to the log and
// returning failure is sufficient. In the long term, we should
// probably have code parsing the log looking for this kind of
// security failure, particularly when there are large numbers of
// them, since the latter is a potential sign of an attack. PLR
ldout(cct, 0) << "Signature failed." << dendl;
return (SESSION_SIGNATURE_FAILURE);
}
return 0;
}
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