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-rw-r--r--fs/smb/server/asn1.c238
1 files changed, 238 insertions, 0 deletions
diff --git a/fs/smb/server/asn1.c b/fs/smb/server/asn1.c
new file mode 100644
index 000000000000..cc6384f79675
--- /dev/null
+++ b/fs/smb/server/asn1.c
@@ -0,0 +1,238 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * The ASB.1/BER parsing code is derived from ip_nat_snmp_basic.c which was in
+ * turn derived from the gxsnmp package by Gregory McLean & Jochen Friedrich
+ *
+ * Copyright (c) 2000 RP Internet (www.rpi.net.au).
+ */
+
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/slab.h>
+#include <linux/oid_registry.h>
+
+#include "glob.h"
+
+#include "asn1.h"
+#include "connection.h"
+#include "auth.h"
+#include "ksmbd_spnego_negtokeninit.asn1.h"
+#include "ksmbd_spnego_negtokentarg.asn1.h"
+
+#define NTLMSSP_OID_LEN 10
+
+static char NTLMSSP_OID_STR[NTLMSSP_OID_LEN] = { 0x2b, 0x06, 0x01, 0x04, 0x01,
+ 0x82, 0x37, 0x02, 0x02, 0x0a };
+
+int
+ksmbd_decode_negTokenInit(unsigned char *security_blob, int length,
+ struct ksmbd_conn *conn)
+{
+ return asn1_ber_decoder(&ksmbd_spnego_negtokeninit_decoder, conn,
+ security_blob, length);
+}
+
+int
+ksmbd_decode_negTokenTarg(unsigned char *security_blob, int length,
+ struct ksmbd_conn *conn)
+{
+ return asn1_ber_decoder(&ksmbd_spnego_negtokentarg_decoder, conn,
+ security_blob, length);
+}
+
+static int compute_asn_hdr_len_bytes(int len)
+{
+ if (len > 0xFFFFFF)
+ return 4;
+ else if (len > 0xFFFF)
+ return 3;
+ else if (len > 0xFF)
+ return 2;
+ else if (len > 0x7F)
+ return 1;
+ else
+ return 0;
+}
+
+static void encode_asn_tag(char *buf, unsigned int *ofs, char tag, char seq,
+ int length)
+{
+ int i;
+ int index = *ofs;
+ char hdr_len = compute_asn_hdr_len_bytes(length);
+ int len = length + 2 + hdr_len;
+
+ /* insert tag */
+ buf[index++] = tag;
+
+ if (!hdr_len) {
+ buf[index++] = len;
+ } else {
+ buf[index++] = 0x80 | hdr_len;
+ for (i = hdr_len - 1; i >= 0; i--)
+ buf[index++] = (len >> (i * 8)) & 0xFF;
+ }
+
+ /* insert seq */
+ len = len - (index - *ofs);
+ buf[index++] = seq;
+
+ if (!hdr_len) {
+ buf[index++] = len;
+ } else {
+ buf[index++] = 0x80 | hdr_len;
+ for (i = hdr_len - 1; i >= 0; i--)
+ buf[index++] = (len >> (i * 8)) & 0xFF;
+ }
+
+ *ofs += (index - *ofs);
+}
+
+int build_spnego_ntlmssp_neg_blob(unsigned char **pbuffer, u16 *buflen,
+ char *ntlm_blob, int ntlm_blob_len)
+{
+ char *buf;
+ unsigned int ofs = 0;
+ int neg_result_len = 4 + compute_asn_hdr_len_bytes(1) * 2 + 1;
+ int oid_len = 4 + compute_asn_hdr_len_bytes(NTLMSSP_OID_LEN) * 2 +
+ NTLMSSP_OID_LEN;
+ int ntlmssp_len = 4 + compute_asn_hdr_len_bytes(ntlm_blob_len) * 2 +
+ ntlm_blob_len;
+ int total_len = 4 + compute_asn_hdr_len_bytes(neg_result_len +
+ oid_len + ntlmssp_len) * 2 +
+ neg_result_len + oid_len + ntlmssp_len;
+
+ buf = kmalloc(total_len, GFP_KERNEL);
+ if (!buf)
+ return -ENOMEM;
+
+ /* insert main gss header */
+ encode_asn_tag(buf, &ofs, 0xa1, 0x30, neg_result_len + oid_len +
+ ntlmssp_len);
+
+ /* insert neg result */
+ encode_asn_tag(buf, &ofs, 0xa0, 0x0a, 1);
+ buf[ofs++] = 1;
+
+ /* insert oid */
+ encode_asn_tag(buf, &ofs, 0xa1, 0x06, NTLMSSP_OID_LEN);
+ memcpy(buf + ofs, NTLMSSP_OID_STR, NTLMSSP_OID_LEN);
+ ofs += NTLMSSP_OID_LEN;
+
+ /* insert response token - ntlmssp blob */
+ encode_asn_tag(buf, &ofs, 0xa2, 0x04, ntlm_blob_len);
+ memcpy(buf + ofs, ntlm_blob, ntlm_blob_len);
+ ofs += ntlm_blob_len;
+
+ *pbuffer = buf;
+ *buflen = total_len;
+ return 0;
+}
+
+int build_spnego_ntlmssp_auth_blob(unsigned char **pbuffer, u16 *buflen,
+ int neg_result)
+{
+ char *buf;
+ unsigned int ofs = 0;
+ int neg_result_len = 4 + compute_asn_hdr_len_bytes(1) * 2 + 1;
+ int total_len = 4 + compute_asn_hdr_len_bytes(neg_result_len) * 2 +
+ neg_result_len;
+
+ buf = kmalloc(total_len, GFP_KERNEL);
+ if (!buf)
+ return -ENOMEM;
+
+ /* insert main gss header */
+ encode_asn_tag(buf, &ofs, 0xa1, 0x30, neg_result_len);
+
+ /* insert neg result */
+ encode_asn_tag(buf, &ofs, 0xa0, 0x0a, 1);
+ if (neg_result)
+ buf[ofs++] = 2;
+ else
+ buf[ofs++] = 0;
+
+ *pbuffer = buf;
+ *buflen = total_len;
+ return 0;
+}
+
+int ksmbd_gssapi_this_mech(void *context, size_t hdrlen, unsigned char tag,
+ const void *value, size_t vlen)
+{
+ enum OID oid;
+
+ oid = look_up_OID(value, vlen);
+ if (oid != OID_spnego) {
+ char buf[50];
+
+ sprint_oid(value, vlen, buf, sizeof(buf));
+ ksmbd_debug(AUTH, "Unexpected OID: %s\n", buf);
+ return -EBADMSG;
+ }
+
+ return 0;
+}
+
+int ksmbd_neg_token_init_mech_type(void *context, size_t hdrlen,
+ unsigned char tag, const void *value,
+ size_t vlen)
+{
+ struct ksmbd_conn *conn = context;
+ enum OID oid;
+ int mech_type;
+
+ oid = look_up_OID(value, vlen);
+ if (oid == OID_ntlmssp) {
+ mech_type = KSMBD_AUTH_NTLMSSP;
+ } else if (oid == OID_mskrb5) {
+ mech_type = KSMBD_AUTH_MSKRB5;
+ } else if (oid == OID_krb5) {
+ mech_type = KSMBD_AUTH_KRB5;
+ } else if (oid == OID_krb5u2u) {
+ mech_type = KSMBD_AUTH_KRB5U2U;
+ } else {
+ char buf[50];
+
+ sprint_oid(value, vlen, buf, sizeof(buf));
+ ksmbd_debug(AUTH, "Unexpected OID: %s\n", buf);
+ return -EBADMSG;
+ }
+
+ conn->auth_mechs |= mech_type;
+ if (conn->preferred_auth_mech == 0)
+ conn->preferred_auth_mech = mech_type;
+
+ return 0;
+}
+
+static int ksmbd_neg_token_alloc(void *context, size_t hdrlen,
+ unsigned char tag, const void *value,
+ size_t vlen)
+{
+ struct ksmbd_conn *conn = context;
+
+ conn->mechToken = kmalloc(vlen + 1, GFP_KERNEL);
+ if (!conn->mechToken)
+ return -ENOMEM;
+
+ memcpy(conn->mechToken, value, vlen);
+ conn->mechToken[vlen] = '\0';
+ return 0;
+}
+
+int ksmbd_neg_token_init_mech_token(void *context, size_t hdrlen,
+ unsigned char tag, const void *value,
+ size_t vlen)
+{
+ return ksmbd_neg_token_alloc(context, hdrlen, tag, value, vlen);
+}
+
+int ksmbd_neg_token_targ_resp_token(void *context, size_t hdrlen,
+ unsigned char tag, const void *value,
+ size_t vlen)
+{
+ return ksmbd_neg_token_alloc(context, hdrlen, tag, value, vlen);
+}