From 31c6679bf12bbcd6626bfd5066bb2e751314e9c2 Mon Sep 17 00:00:00 2001 From: Stefan Metzmacher Date: Fri, 22 May 2009 22:58:39 +0200 Subject: s3:smbd: add support for SMB2 signing metze --- source3/smbd/smb2_signing.c | 135 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 135 insertions(+) create mode 100644 source3/smbd/smb2_signing.c (limited to 'source3/smbd/smb2_signing.c') diff --git a/source3/smbd/smb2_signing.c b/source3/smbd/smb2_signing.c new file mode 100644 index 0000000000..55ed4f6d1c --- /dev/null +++ b/source3/smbd/smb2_signing.c @@ -0,0 +1,135 @@ +/* + Unix SMB/CIFS implementation. + SMB2 signing + + Copyright (C) Stefan Metzmacher 2009 + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see . +*/ + +#include "includes.h" +#include "smbd/globals.h" +#include "../source4/libcli/smb2/smb2_constants.h" +#include "../lib/crypto/crypto.h" + +NTSTATUS smb2_signing_sign_pdu(DATA_BLOB session_key, + struct iovec *vector, + int count) +{ + uint8_t *hdr; + uint64_t session_id; + struct HMACSHA256Context m; + uint8_t res[SHA256_DIGEST_LENGTH]; + int i; + + if (count < 2) { + return NT_STATUS_INVALID_PARAMETER; + } + + if (vector[0].iov_len != SMB2_HDR_BODY) { + return NT_STATUS_INVALID_PARAMETER; + } + + hdr = (uint8_t *)vector[0].iov_base; + + session_id = BVAL(hdr, SMB2_HDR_SESSION_ID); + if (session_id == 0) { + /* + * do not sign messages with a zero session_id. + * See MS-SMB2 3.2.4.1.1 + */ + return NT_STATUS_OK; + } + + if (session_key.length == 0) { + DEBUG(2,("Wrong session key length %u for SMB2 signing\n", + (unsigned)session_key.length)); + return NT_STATUS_ACCESS_DENIED; + } + + memset(hdr + SMB2_HDR_SIGNATURE, 0, 16); + + SIVAL(hdr, SMB2_HDR_FLAGS, IVAL(hdr, SMB2_HDR_FLAGS) | SMB2_HDR_FLAG_SIGNED); + + ZERO_STRUCT(m); + hmac_sha256_init(session_key.data, MIN(session_key.length, 16), &m); + for (i=0; i < count; i++) { + hmac_sha256_update((const uint8_t *)vector[i].iov_base, + vector[i].iov_len, &m); + } + hmac_sha256_final(res, &m); + DEBUG(5,("signed SMB2 message\n")); + + memcpy(hdr + SMB2_HDR_SIGNATURE, res, 16); + + return NT_STATUS_OK; +} + +NTSTATUS smb2_signing_check_pdu(DATA_BLOB session_key, + const struct iovec *vector, + int count) +{ + const uint8_t *hdr; + const uint8_t *sig; + uint64_t session_id; + struct HMACSHA256Context m; + uint8_t res[SHA256_DIGEST_LENGTH]; + static const uint8_t zero_sig[16]; + int i; + + if (count < 2) { + return NT_STATUS_INVALID_PARAMETER; + } + + if (vector[0].iov_len != SMB2_HDR_BODY) { + return NT_STATUS_INVALID_PARAMETER; + } + + hdr = (const uint8_t *)vector[0].iov_base; + + session_id = BVAL(hdr, SMB2_HDR_SESSION_ID); + if (session_id == 0) { + /* + * do not sign messages with a zero session_id. + * See MS-SMB2 3.2.4.1.1 + */ + return NT_STATUS_OK; + } + + if (session_key.length == 0) { + /* we don't have the session key yet */ + return NT_STATUS_OK; + } + + sig = hdr+SMB2_HDR_SIGNATURE; + + ZERO_STRUCT(m); + hmac_sha256_init(session_key.data, MIN(session_key.length, 16), &m); + hmac_sha256_update(hdr, SMB2_HDR_SIGNATURE, &m); + hmac_sha256_update(zero_sig, 16, &m); + for (i=1; i < count; i++) { + hmac_sha256_update((const uint8_t *)vector[i].iov_base, + vector[i].iov_len, &m); + } + hmac_sha256_final(res, &m); + + if (memcmp(res, sig, 16) != 0) { + DEBUG(0,("Bad SMB2 signature for message\n")); + dump_data(0, sig, 16); + dump_data(0, res, 16); + return NT_STATUS_ACCESS_DENIED; + } + + return NT_STATUS_OK; +} -- cgit