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190b2c4f8a
attacks and is required to connect to Windows 2003 servers in their default configuration. This adds an extra field to the SMB header containing the truncated 64-bit MD5 digest of a key (a function of the user's password and the server's authentication challenge), an implicit sequence number, and the message data itself. As signing each message imposes a significant performance penalty, we only enable it if the server will not let us connect without it; this should eventually become an option to mount_smbfs.
340 lines
9.0 KiB
C
340 lines
9.0 KiB
C
/*
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* Copyright (c) 2000-2001, Boris Popov
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* All rights reserved.
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*
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* Copyright (c) 2003, 2004 Tim J. Robbins.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by Boris Popov.
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* 4. Neither the name of the author nor the names of any co-contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/param.h>
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#include <sys/malloc.h>
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#include <sys/kernel.h>
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#include <sys/systm.h>
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#include <sys/conf.h>
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#include <sys/proc.h>
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#include <sys/fcntl.h>
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#include <sys/socket.h>
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#include <sys/socketvar.h>
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#include <sys/sysctl.h>
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#include <sys/endian.h>
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#include <sys/mbuf.h>
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#include <sys/mchain.h>
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#include <sys/md4.h>
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#include <sys/md5.h>
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#include <sys/iconv.h>
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#include <netsmb/smb.h>
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#include <netsmb/smb_conn.h>
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#include <netsmb/smb_subr.h>
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#include <netsmb/smb_rq.h>
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#include <netsmb/smb_dev.h>
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#include "opt_netsmb.h"
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#ifdef NETSMBCRYPTO
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#include <crypto/des/des.h>
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static u_char N8[] = {0x4b, 0x47, 0x53, 0x21, 0x40, 0x23, 0x24, 0x25};
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static void
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smb_E(const u_char *key, u_char *data, u_char *dest)
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{
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des_key_schedule *ksp;
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u_char kk[8];
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kk[0] = key[0] & 0xfe;
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kk[1] = key[0] << 7 | (key[1] >> 1 & 0xfe);
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kk[2] = key[1] << 6 | (key[2] >> 2 & 0xfe);
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kk[3] = key[2] << 5 | (key[3] >> 3 & 0xfe);
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kk[4] = key[3] << 4 | (key[4] >> 4 & 0xfe);
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kk[5] = key[4] << 3 | (key[5] >> 5 & 0xfe);
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kk[6] = key[5] << 2 | (key[6] >> 6 & 0xfe);
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kk[7] = key[6] << 1;
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ksp = malloc(sizeof(des_key_schedule), M_SMBTEMP, M_WAITOK);
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des_set_key((des_cblock *)kk, *ksp);
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des_ecb_encrypt((des_cblock *)data, (des_cblock *)dest, *ksp, 1);
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free(ksp, M_SMBTEMP);
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}
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#endif
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int
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smb_encrypt(const u_char *apwd, u_char *C8, u_char *RN)
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{
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#ifdef NETSMBCRYPTO
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u_char *p, *P14, *S21;
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p = malloc(14 + 21, M_SMBTEMP, M_WAITOK);
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bzero(p, 14 + 21);
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P14 = p;
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S21 = p + 14;
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bcopy(apwd, P14, min(14, strlen(apwd)));
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/*
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* S21 = concat(Ex(P14, N8), zeros(5));
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*/
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smb_E(P14, N8, S21);
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smb_E(P14 + 7, N8, S21 + 8);
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smb_E(S21, C8, RN);
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smb_E(S21 + 7, C8, RN + 8);
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smb_E(S21 + 14, C8, RN + 16);
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free(p, M_SMBTEMP);
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return 0;
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#else
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SMBERROR("password encryption is not available\n");
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bzero(RN, 24);
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return EAUTH;
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#endif
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}
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int
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smb_ntencrypt(const u_char *apwd, u_char *C8, u_char *RN)
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{
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#ifdef NETSMBCRYPTO
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u_char S21[21];
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u_int16_t *unipwd;
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MD4_CTX *ctxp;
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int len;
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len = strlen(apwd);
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unipwd = malloc((len + 1) * sizeof(u_int16_t), M_SMBTEMP, M_WAITOK);
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/*
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* S21 = concat(MD4(U(apwd)), zeros(5));
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*/
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smb_strtouni(unipwd, apwd);
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ctxp = malloc(sizeof(MD4_CTX), M_SMBTEMP, M_WAITOK);
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MD4Init(ctxp);
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MD4Update(ctxp, (u_char*)unipwd, len * sizeof(u_int16_t));
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free(unipwd, M_SMBTEMP);
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bzero(S21, 21);
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MD4Final(S21, ctxp);
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free(ctxp, M_SMBTEMP);
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smb_E(S21, C8, RN);
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smb_E(S21 + 7, C8, RN + 8);
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smb_E(S21 + 14, C8, RN + 16);
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return 0;
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#else
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SMBERROR("password encryption is not available\n");
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bzero(RN, 24);
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return EAUTH;
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#endif
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}
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/*
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* Calculate message authentication code (MAC) key for virtual circuit.
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*/
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int
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smb_calcmackey(struct smb_vc *vcp)
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{
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#ifdef NETSMBCRYPTO
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const char *pwd;
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u_int16_t *unipwd;
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int len;
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MD4_CTX md4;
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u_char S16[16], S21[21];
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KASSERT(vcp->vc_hflags2 & SMB_FLAGS2_SECURITY_SIGNATURE,
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("signatures not enabled"));
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if (vcp->vc_mackey != NULL) {
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free(vcp->vc_mackey, M_SMBTEMP);
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vcp->vc_mackey = NULL;
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vcp->vc_mackeylen = 0;
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vcp->vc_seqno = 0;
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}
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/*
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* The partial MAC key is the concatenation of the 16 byte session
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* key and the 24 byte challenge response.
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*/
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vcp->vc_mackeylen = 16 + 24;
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vcp->vc_mackey = malloc(vcp->vc_mackeylen, M_SMBTEMP, M_WAITOK);
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/*
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* Calculate session key:
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* MD4(MD4(U(PN)))
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*/
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pwd = smb_vc_getpass(vcp);
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len = strlen(pwd);
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unipwd = malloc((len + 1) * sizeof(u_int16_t), M_SMBTEMP, M_WAITOK);
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smb_strtouni(unipwd, pwd);
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MD4Init(&md4);
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MD4Update(&md4, (u_char *)unipwd, len * sizeof(u_int16_t));
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MD4Final(S16, &md4);
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MD4Init(&md4);
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MD4Update(&md4, S16, 16);
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MD4Final(vcp->vc_mackey, &md4);
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free(unipwd, M_SMBTEMP);
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/*
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* Calculate response to challenge:
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* Ex(concat(MD4(U(pass)), zeros(5)), C8)
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*/
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bzero(S21, 21);
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bcopy(S16, S21, 16);
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smb_E(S21, vcp->vc_ch, vcp->vc_mackey + 16);
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smb_E(S21 + 7, vcp->vc_ch, vcp->vc_mackey + 24);
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smb_E(S21 + 14, vcp->vc_ch, vcp->vc_mackey + 32);
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return (0);
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#else
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panic("smb_calcmackey: encryption not available");
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return (0);
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#endif /* NETSMBCRYPTO */
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}
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/*
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* Sign request with MAC.
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*/
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int
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smb_rq_sign(struct smb_rq *rqp)
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{
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#ifdef NETSMBCRYPTO
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struct smb_vc *vcp = rqp->sr_vc;
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struct mbchain *mbp;
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struct mbuf *mb;
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MD5_CTX md5;
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u_char digest[16];
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KASSERT(vcp->vc_hflags2 & SMB_FLAGS2_SECURITY_SIGNATURE,
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("signatures not enabled"));
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if (vcp->vc_mackey == NULL)
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/* XXX Should assert that cmd == SMB_COM_NEGOTIATE. */
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return (0);
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/*
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* This is a bit of a kludge. If the request is non-TRANSACTION,
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* or it is the first request of a transaction, give it the next
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* sequence number, and expect the reply to have the sequence number
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* following that one. Otherwise, it is a secondary request in
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* a transaction, and it gets the same sequence numbers as the
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* primary request.
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*/
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if (rqp->sr_t2 == NULL ||
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(rqp->sr_t2->t2_flags & SMBT2_SECONDARY) == 0) {
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rqp->sr_seqno = vcp->vc_seqno++;
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rqp->sr_rseqno = vcp->vc_seqno++;
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} else {
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/*
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* Sequence numbers are already in the struct because
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* smb_t2_request_int() uses the same one for all the
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* requests in the transaction.
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* (At least we hope so.)
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*/
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KASSERT(rqp->sr_t2 == NULL ||
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(rqp->sr_t2->t2_flags & SMBT2_SECONDARY) == 0 ||
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rqp->sr_t2->t2_rq == rqp,
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("sec t2 rq not using same smb_rq"));
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}
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/* Initialize sec. signature field to sequence number + zeros. */
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*(u_int32_t *)rqp->sr_rqsig = htole32(rqp->sr_seqno);
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*(u_int32_t *)(rqp->sr_rqsig + 4) = 0;
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/*
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* Compute HMAC-MD5 of packet data, keyed by MAC key.
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* Store the first 8 bytes in the sec. signature field.
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*/
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smb_rq_getrequest(rqp, &mbp);
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MD5Init(&md5);
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MD5Update(&md5, vcp->vc_mackey, vcp->vc_mackeylen);
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for (mb = mbp->mb_top; mb != NULL; mb = mb->m_next)
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MD5Update(&md5, mtod(mb, void *), mb->m_len);
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MD5Final(digest, &md5);
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bcopy(digest, rqp->sr_rqsig, 8);
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return (0);
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#else
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panic("smb_rq_sign: encryption not available");
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return (0);
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#endif /* NETSMBCRYPTO */
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}
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/*
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* Verify reply signature.
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*/
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int
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smb_rq_verify(struct smb_rq *rqp)
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{
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#ifdef NETSMBCRYPTO
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struct smb_vc *vcp = rqp->sr_vc;
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struct mdchain *mdp;
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u_char sigbuf[8];
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MD5_CTX md5;
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u_char digest[16];
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struct mbuf *mb;
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KASSERT(vcp->vc_hflags2 & SMB_FLAGS2_SECURITY_SIGNATURE,
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("signatures not enabled"));
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if (vcp->vc_mackey == NULL)
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/* XXX Should check that this is a SMB_COM_NEGOTIATE reply. */
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return (0);
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/*
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* Compute HMAC-MD5 of packet data, keyed by MAC key.
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* We play games to pretend the security signature field
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* contains their sequence number, to avoid modifying
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* the packet itself.
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*/
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smb_rq_getreply(rqp, &mdp);
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mb = mdp->md_top;
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KASSERT(mb->m_len >= SMB_HDRLEN, ("forgot to m_pullup"));
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MD5Init(&md5);
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MD5Update(&md5, vcp->vc_mackey, vcp->vc_mackeylen);
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MD5Update(&md5, mtod(mb, void *), 14);
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*(u_int32_t *)sigbuf = htole32(rqp->sr_rseqno);
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*(u_int32_t *)(sigbuf + 4) = 0;
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MD5Update(&md5, sigbuf, 8);
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MD5Update(&md5, mtod(mb, u_char *) + 22, mb->m_len - 22);
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for (mb = mb->m_next; mb != NULL; mb = mb->m_next)
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MD5Update(&md5, mtod(mb, void *), mb->m_len);
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MD5Final(digest, &md5);
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/*
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* Now verify the signature.
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*/
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if (bcmp(mtod(mdp->md_top, u_char *) + 14, digest, 8) != 0)
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return (EAUTH);
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return (0);
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#else
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panic("smb_rq_verify: encryption not available");
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return (0);
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#endif /* NETSMBCRYPTO */
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}
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