sys/netsmb/smb_crypt.c

   1 /*-
   2  * SPDX-License-Identifier: BSD-4-Clause
   3  *
   4  * Copyright (c) 2000-2001, Boris Popov
   5  * All rights reserved.
   6  *
   7  * Copyright (c) 2003, 2004 Tim J. Robbins.
   8  * All rights reserved.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  * 3. All advertising materials mentioning features or use of this software
  19  *    must display the following acknowledgement:
  20  *    This product includes software developed by Boris Popov.
  21  * 4. Neither the name of the author nor the names of any co-contributors
  22  *    may be used to endorse or promote products derived from this software
  23  *    without specific prior written permission.
  24  *
  25  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  26  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  27  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  28  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  29  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  30  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  31  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  32  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  33  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  34  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  35  * SUCH DAMAGE.
  36  */
  37
  38 #include <sys/param.h>
  39 #include <sys/malloc.h>
  40 #include <sys/kernel.h>
  41 #include <sys/systm.h>
  42 #include <sys/conf.h>
  43 #include <sys/proc.h>
  44 #include <sys/fcntl.h>
  45 #include <sys/socket.h>
  46 #include <sys/socketvar.h>
  47 #include <sys/sysctl.h>
  48 #include <sys/endian.h>
  49 #include <sys/mbuf.h>
  50 #include <sys/mchain.h>
  51 #include <sys/md4.h>
  52 #include <sys/md5.h>
  53 #include <sys/iconv.h>
  54
  55 #include <netsmb/smb.h>
  56 #include <netsmb/smb_conn.h>
  57 #include <netsmb/smb_subr.h>
  58 #include <netsmb/smb_rq.h>
  59 #include <netsmb/smb_dev.h>
  60
  61 #include <crypto/des/des.h>
  62
  63 #include "opt_netsmb.h"
  64
  65 static u_char N8[] = {0x4b, 0x47, 0x53, 0x21, 0x40, 0x23, 0x24, 0x25};
  66
  67 static void
  68 smb_E(const u_char *key, u_char *data, u_char *dest)
  69 {
  70         des_key_schedule *ksp;
  71         u_char kk[8];
  72
  73         kk[0] = key[0] & 0xfe;
  74         kk[1] = key[0] << 7 | (key[1] >> 1 & 0xfe);
  75         kk[2] = key[1] << 6 | (key[2] >> 2 & 0xfe);
  76         kk[3] = key[2] << 5 | (key[3] >> 3 & 0xfe);
  77         kk[4] = key[3] << 4 | (key[4] >> 4 & 0xfe);
  78         kk[5] = key[4] << 3 | (key[5] >> 5 & 0xfe);
  79         kk[6] = key[5] << 2 | (key[6] >> 6 & 0xfe);
  80         kk[7] = key[6] << 1;
  81         ksp = malloc(sizeof(des_key_schedule), M_SMBTEMP, M_WAITOK);
  82         des_set_key(kk, *ksp);
  83         des_ecb_encrypt(data, dest, *ksp, 1);
  84         free(ksp, M_SMBTEMP);
  85 }
  86
  87 int
  88 smb_encrypt(const u_char *apwd, u_char *C8, u_char *RN)
  89 {
  90         u_char *p, *P14, *S21;
  91
  92         p = malloc(14 + 21, M_SMBTEMP, M_WAITOK);
  93         bzero(p, 14 + 21);
  94         P14 = p;
  95         S21 = p + 14;
  96         bcopy(apwd, P14, min(14, strlen(apwd)));
  97         /*
  98          * S21 = concat(Ex(P14, N8), zeros(5));
  99          */
 100         smb_E(P14, N8, S21);
 101         smb_E(P14 + 7, N8, S21 + 8);
 102
 103         smb_E(S21, C8, RN);
 104         smb_E(S21 + 7, C8, RN + 8);
 105         smb_E(S21 + 14, C8, RN + 16);
 106         free(p, M_SMBTEMP);
 107         return 0;
 108 }
 109
 110 int
 111 smb_ntencrypt(const u_char *apwd, u_char *C8, u_char *RN)
 112 {
 113         u_char S21[21];
 114         u_int16_t *unipwd;
 115         MD4_CTX *ctxp;
 116         u_int len;
 117
 118         len = strlen(apwd);
 119         unipwd = malloc((len + 1) * sizeof(u_int16_t), M_SMBTEMP, M_WAITOK);
 120         /*
 121          * S21 = concat(MD4(U(apwd)), zeros(5));
 122          */
 123         smb_strtouni(unipwd, apwd);
 124         ctxp = malloc(sizeof(MD4_CTX), M_SMBTEMP, M_WAITOK);
 125         MD4Init(ctxp);
 126         MD4Update(ctxp, (u_char*)unipwd, len * sizeof(u_int16_t));
 127         free(unipwd, M_SMBTEMP);
 128         bzero(S21, 21);
 129         MD4Final(S21, ctxp);
 130         free(ctxp, M_SMBTEMP);
 131
 132         smb_E(S21, C8, RN);
 133         smb_E(S21 + 7, C8, RN + 8);
 134         smb_E(S21 + 14, C8, RN + 16);
 135         return 0;
 136 }
 137
 138 /*
 139  * Calculate message authentication code (MAC) key for virtual circuit.
 140  */
 141 int
 142 smb_calcmackey(struct smb_vc *vcp)
 143 {
 144         const char *pwd;
 145         u_int16_t *unipwd;
 146         u_int len;
 147         MD4_CTX md4;
 148         u_char S16[16], S21[21];
 149
 150         KASSERT(vcp->vc_hflags2 & SMB_FLAGS2_SECURITY_SIGNATURE,
 151             ("signatures not enabled"));
 152
 153         if (vcp->vc_mackey != NULL) {
 154                 free(vcp->vc_mackey, M_SMBTEMP);
 155                 vcp->vc_mackey = NULL;
 156                 vcp->vc_mackeylen = 0;
 157                 vcp->vc_seqno = 0;
 158         }
 159
 160         /*
 161          * The partial MAC key is the concatenation of the 16 byte session
 162          * key and the 24 byte challenge response.
 163          */
 164         vcp->vc_mackeylen = 16 + 24;
 165         vcp->vc_mackey = malloc(vcp->vc_mackeylen, M_SMBTEMP, M_WAITOK);
 166
 167         /*
 168          * Calculate session key:
 169          *      MD4(MD4(U(PN)))
 170          */
 171         pwd = smb_vc_getpass(vcp);
 172         len = strlen(pwd);
 173         unipwd = malloc((len + 1) * sizeof(u_int16_t), M_SMBTEMP, M_WAITOK);
 174         smb_strtouni(unipwd, pwd);
 175         MD4Init(&md4);
 176         MD4Update(&md4, (u_char *)unipwd, len * sizeof(u_int16_t));
 177         MD4Final(S16, &md4);
 178         MD4Init(&md4);
 179         MD4Update(&md4, S16, 16);
 180         MD4Final(vcp->vc_mackey, &md4);
 181         free(unipwd, M_SMBTEMP);
 182
 183         /*
 184          * Calculate response to challenge:
 185          *      Ex(concat(MD4(U(pass)), zeros(5)), C8)
 186          */
 187         bzero(S21, 21);
 188         bcopy(S16, S21, 16);
 189         smb_E(S21, vcp->vc_ch, vcp->vc_mackey + 16);
 190         smb_E(S21 + 7, vcp->vc_ch, vcp->vc_mackey + 24);
 191         smb_E(S21 + 14, vcp->vc_ch, vcp->vc_mackey + 32);
 192
 193         return (0);
 194 }
 195
 196 /*
 197  * Sign request with MAC.
 198  */
 199 int
 200 smb_rq_sign(struct smb_rq *rqp)
 201 {
 202         struct smb_vc *vcp = rqp->sr_vc;
 203         struct mbchain *mbp;
 204         struct mbuf *mb;
 205         MD5_CTX md5;
 206         u_char digest[16];
 207
 208         KASSERT(vcp->vc_hflags2 & SMB_FLAGS2_SECURITY_SIGNATURE,
 209             ("signatures not enabled"));
 210
 211         if (vcp->vc_mackey == NULL)
 212                 /* XXX Should assert that cmd == SMB_COM_NEGOTIATE. */
 213                 return (0);
 214
 215         /*
 216          * This is a bit of a kludge. If the request is non-TRANSACTION,
 217          * or it is the first request of a transaction, give it the next
 218          * sequence number, and expect the reply to have the sequence number
 219          * following that one. Otherwise, it is a secondary request in
 220          * a transaction, and it gets the same sequence numbers as the
 221          * primary request.
 222          */
 223         if (rqp->sr_t2 == NULL ||
 224             (rqp->sr_t2->t2_flags & SMBT2_SECONDARY) == 0) {
 225                 rqp->sr_seqno = vcp->vc_seqno++;
 226                 rqp->sr_rseqno = vcp->vc_seqno++;
 227         } else {
 228                 /*
 229                  * Sequence numbers are already in the struct because
 230                  * smb_t2_request_int() uses the same one for all the
 231                  * requests in the transaction.
 232                  * (At least we hope so.)
 233                  */
 234                 KASSERT(rqp->sr_t2 == NULL ||
 235                     (rqp->sr_t2->t2_flags & SMBT2_SECONDARY) == 0 ||
 236                     rqp->sr_t2->t2_rq == rqp,
 237                     ("sec t2 rq not using same smb_rq"));
 238         }
 239
 240         /* Initialize sec. signature field to sequence number + zeros. */
 241         le32enc(rqp->sr_rqsig, rqp->sr_seqno);
 242         le32enc(rqp->sr_rqsig + 4, 0);
 243
 244         /*
 245          * Compute HMAC-MD5 of packet data, keyed by MAC key.
 246          * Store the first 8 bytes in the sec. signature field.
 247          */
 248         smb_rq_getrequest(rqp, &mbp);
 249         MD5Init(&md5);
 250         MD5Update(&md5, vcp->vc_mackey, vcp->vc_mackeylen);
 251         for (mb = mbp->mb_top; mb != NULL; mb = mb->m_next)
 252                 MD5Update(&md5, mtod(mb, void *), mb->m_len);
 253         MD5Final(digest, &md5);
 254         bcopy(digest, rqp->sr_rqsig, 8);
 255
 256         return (0);
 257 }
 258
 259 /*
 260  * Verify reply signature.
 261  */
 262 int
 263 smb_rq_verify(struct smb_rq *rqp)
 264 {
 265         struct smb_vc *vcp = rqp->sr_vc;
 266         struct mdchain *mdp;
 267         u_char sigbuf[8];
 268         MD5_CTX md5;
 269         u_char digest[16];
 270         struct mbuf *mb;
 271
 272         KASSERT(vcp->vc_hflags2 & SMB_FLAGS2_SECURITY_SIGNATURE,
 273             ("signatures not enabled"));
 274
 275         if (vcp->vc_mackey == NULL)
 276                 /* XXX Should check that this is a SMB_COM_NEGOTIATE reply. */
 277                 return (0);
 278
 279         /*
 280          * Compute HMAC-MD5 of packet data, keyed by MAC key.
 281          * We play games to pretend the security signature field
 282          * contains their sequence number, to avoid modifying
 283          * the packet itself.
 284          */
 285         smb_rq_getreply(rqp, &mdp);
 286         mb = mdp->md_top;
 287         KASSERT(mb->m_len >= SMB_HDRLEN, ("forgot to m_pullup"));
 288         MD5Init(&md5);
 289         MD5Update(&md5, vcp->vc_mackey, vcp->vc_mackeylen);
 290         MD5Update(&md5, mtod(mb, void *), 14);
 291         *(u_int32_t *)sigbuf = htole32(rqp->sr_rseqno);
 292         *(u_int32_t *)(sigbuf + 4) = 0;
 293         MD5Update(&md5, sigbuf, 8);
 294         MD5Update(&md5, mtod(mb, u_char *) + 22, mb->m_len - 22);
 295         for (mb = mb->m_next; mb != NULL; mb = mb->m_next)
 296                 MD5Update(&md5, mtod(mb, void *), mb->m_len);
 297         MD5Final(digest, &md5);
 298
 299         /*
 300          * Now verify the signature.
 301          */
 302         if (bcmp(mtod(mdp->md_top, u_char *) + 14, digest, 8) != 0)
 303                 return (EAUTH);
 304
 305         return (0);
 306 }