diff options
Diffstat (limited to 'fs/smb/server/asn1.c')
| -rw-r--r-- | fs/smb/server/asn1.c | 238 |
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); +} |