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1// SPDX-License-Identifier: GPL-2.0-or-later2/*3 * The ASB.1/BER parsing code is derived from ip_nat_snmp_basic.c which was in4 * turn derived from the gxsnmp package by Gregory McLean & Jochen Friedrich5 *6 * Copyright (c) 2000 RP Internet (www.rpi.net.au).7 */8 9#include <linux/module.h>10#include <linux/types.h>11#include <linux/kernel.h>12#include <linux/mm.h>13#include <linux/slab.h>14#include <linux/oid_registry.h>15 16#include "glob.h"17 18#include "asn1.h"19#include "connection.h"20#include "auth.h"21#include "ksmbd_spnego_negtokeninit.asn1.h"22#include "ksmbd_spnego_negtokentarg.asn1.h"23 24#define NTLMSSP_OID_LEN 1025 26static char NTLMSSP_OID_STR[NTLMSSP_OID_LEN] = { 0x2b, 0x06, 0x01, 0x04, 0x01,27 0x82, 0x37, 0x02, 0x02, 0x0a };28 29int30ksmbd_decode_negTokenInit(unsigned char *security_blob, int length,31 struct ksmbd_conn *conn)32{33 return asn1_ber_decoder(&ksmbd_spnego_negtokeninit_decoder, conn,34 security_blob, length);35}36 37int38ksmbd_decode_negTokenTarg(unsigned char *security_blob, int length,39 struct ksmbd_conn *conn)40{41 return asn1_ber_decoder(&ksmbd_spnego_negtokentarg_decoder, conn,42 security_blob, length);43}44 45static int compute_asn_hdr_len_bytes(int len)46{47 if (len > 0xFFFFFF)48 return 4;49 else if (len > 0xFFFF)50 return 3;51 else if (len > 0xFF)52 return 2;53 else if (len > 0x7F)54 return 1;55 else56 return 0;57}58 59static void encode_asn_tag(char *buf, unsigned int *ofs, char tag, char seq,60 int length)61{62 int i;63 int index = *ofs;64 char hdr_len = compute_asn_hdr_len_bytes(length);65 int len = length + 2 + hdr_len;66 67 /* insert tag */68 buf[index++] = tag;69 70 if (!hdr_len) {71 buf[index++] = len;72 } else {73 buf[index++] = 0x80 | hdr_len;74 for (i = hdr_len - 1; i >= 0; i--)75 buf[index++] = (len >> (i * 8)) & 0xFF;76 }77 78 /* insert seq */79 len = len - (index - *ofs);80 buf[index++] = seq;81 82 if (!hdr_len) {83 buf[index++] = len;84 } else {85 buf[index++] = 0x80 | hdr_len;86 for (i = hdr_len - 1; i >= 0; i--)87 buf[index++] = (len >> (i * 8)) & 0xFF;88 }89 90 *ofs += (index - *ofs);91}92 93int build_spnego_ntlmssp_neg_blob(unsigned char **pbuffer, u16 *buflen,94 char *ntlm_blob, int ntlm_blob_len)95{96 char *buf;97 unsigned int ofs = 0;98 int neg_result_len = 4 + compute_asn_hdr_len_bytes(1) * 2 + 1;99 int oid_len = 4 + compute_asn_hdr_len_bytes(NTLMSSP_OID_LEN) * 2 +100 NTLMSSP_OID_LEN;101 int ntlmssp_len = 4 + compute_asn_hdr_len_bytes(ntlm_blob_len) * 2 +102 ntlm_blob_len;103 int total_len = 4 + compute_asn_hdr_len_bytes(neg_result_len +104 oid_len + ntlmssp_len) * 2 +105 neg_result_len + oid_len + ntlmssp_len;106 107 buf = kmalloc(total_len, GFP_KERNEL);108 if (!buf)109 return -ENOMEM;110 111 /* insert main gss header */112 encode_asn_tag(buf, &ofs, 0xa1, 0x30, neg_result_len + oid_len +113 ntlmssp_len);114 115 /* insert neg result */116 encode_asn_tag(buf, &ofs, 0xa0, 0x0a, 1);117 buf[ofs++] = 1;118 119 /* insert oid */120 encode_asn_tag(buf, &ofs, 0xa1, 0x06, NTLMSSP_OID_LEN);121 memcpy(buf + ofs, NTLMSSP_OID_STR, NTLMSSP_OID_LEN);122 ofs += NTLMSSP_OID_LEN;123 124 /* insert response token - ntlmssp blob */125 encode_asn_tag(buf, &ofs, 0xa2, 0x04, ntlm_blob_len);126 memcpy(buf + ofs, ntlm_blob, ntlm_blob_len);127 ofs += ntlm_blob_len;128 129 *pbuffer = buf;130 *buflen = total_len;131 return 0;132}133 134int build_spnego_ntlmssp_auth_blob(unsigned char **pbuffer, u16 *buflen,135 int neg_result)136{137 char *buf;138 unsigned int ofs = 0;139 int neg_result_len = 4 + compute_asn_hdr_len_bytes(1) * 2 + 1;140 int total_len = 4 + compute_asn_hdr_len_bytes(neg_result_len) * 2 +141 neg_result_len;142 143 buf = kmalloc(total_len, GFP_KERNEL);144 if (!buf)145 return -ENOMEM;146 147 /* insert main gss header */148 encode_asn_tag(buf, &ofs, 0xa1, 0x30, neg_result_len);149 150 /* insert neg result */151 encode_asn_tag(buf, &ofs, 0xa0, 0x0a, 1);152 if (neg_result)153 buf[ofs++] = 2;154 else155 buf[ofs++] = 0;156 157 *pbuffer = buf;158 *buflen = total_len;159 return 0;160}161 162int ksmbd_gssapi_this_mech(void *context, size_t hdrlen, unsigned char tag,163 const void *value, size_t vlen)164{165 enum OID oid;166 167 oid = look_up_OID(value, vlen);168 if (oid != OID_spnego) {169 char buf[50];170 171 sprint_oid(value, vlen, buf, sizeof(buf));172 ksmbd_debug(AUTH, "Unexpected OID: %s\n", buf);173 return -EBADMSG;174 }175 176 return 0;177}178 179int ksmbd_neg_token_init_mech_type(void *context, size_t hdrlen,180 unsigned char tag, const void *value,181 size_t vlen)182{183 struct ksmbd_conn *conn = context;184 enum OID oid;185 int mech_type;186 187 oid = look_up_OID(value, vlen);188 if (oid == OID_ntlmssp) {189 mech_type = KSMBD_AUTH_NTLMSSP;190 } else if (oid == OID_mskrb5) {191 mech_type = KSMBD_AUTH_MSKRB5;192 } else if (oid == OID_krb5) {193 mech_type = KSMBD_AUTH_KRB5;194 } else if (oid == OID_krb5u2u) {195 mech_type = KSMBD_AUTH_KRB5U2U;196 } else {197 char buf[50];198 199 sprint_oid(value, vlen, buf, sizeof(buf));200 ksmbd_debug(AUTH, "Unexpected OID: %s\n", buf);201 return -EBADMSG;202 }203 204 conn->auth_mechs |= mech_type;205 if (conn->preferred_auth_mech == 0)206 conn->preferred_auth_mech = mech_type;207 208 return 0;209}210 211static int ksmbd_neg_token_alloc(void *context, size_t hdrlen,212 unsigned char tag, const void *value,213 size_t vlen)214{215 struct ksmbd_conn *conn = context;216 217 if (!vlen)218 return -EINVAL;219 220 conn->mechToken = kmemdup_nul(value, vlen, GFP_KERNEL);221 if (!conn->mechToken)222 return -ENOMEM;223 224 conn->mechTokenLen = (unsigned int)vlen;225 226 return 0;227}228 229int ksmbd_neg_token_init_mech_token(void *context, size_t hdrlen,230 unsigned char tag, const void *value,231 size_t vlen)232{233 return ksmbd_neg_token_alloc(context, hdrlen, tag, value, vlen);234}235 236int ksmbd_neg_token_targ_resp_token(void *context, size_t hdrlen,237 unsigned char tag, const void *value,238 size_t vlen)239{240 return ksmbd_neg_token_alloc(context, hdrlen, tag, value, vlen);241}242