linux/fs/ksmbd/asn1.c
Namjae Jeon 1a93084b9a ksmbd: move fs/cifsd to fs/ksmbd
Move fs/cifsd to fs/ksmbd and rename the remaining cifsd name to ksmbd.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2021-06-28 16:28:31 +09:00

344 lines
7.6 KiB
C

// 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 SPNEGO_OID_LEN 7
#define NTLMSSP_OID_LEN 10
#define KRB5_OID_LEN 7
#define KRB5U2U_OID_LEN 8
#define MSKRB5_OID_LEN 7
static unsigned long SPNEGO_OID[7] = { 1, 3, 6, 1, 5, 5, 2 };
static unsigned long NTLMSSP_OID[10] = { 1, 3, 6, 1, 4, 1, 311, 2, 2, 10 };
static unsigned long KRB5_OID[7] = { 1, 2, 840, 113554, 1, 2, 2 };
static unsigned long KRB5U2U_OID[8] = { 1, 2, 840, 113554, 1, 2, 2, 3 };
static unsigned long MSKRB5_OID[7] = { 1, 2, 840, 48018, 1, 2, 2 };
static char NTLMSSP_OID_STR[NTLMSSP_OID_LEN] = { 0x2b, 0x06, 0x01, 0x04, 0x01,
0x82, 0x37, 0x02, 0x02, 0x0a };
static bool
asn1_subid_decode(const unsigned char **begin, const unsigned char *end,
unsigned long *subid)
{
const unsigned char *ptr = *begin;
unsigned char ch;
*subid = 0;
do {
if (ptr >= end)
return false;
ch = *ptr++;
*subid <<= 7;
*subid |= ch & 0x7F;
} while ((ch & 0x80) == 0x80);
*begin = ptr;
return true;
}
static bool asn1_oid_decode(const unsigned char *value, size_t vlen,
unsigned long **oid, size_t *oidlen)
{
const unsigned char *iptr = value, *end = value + vlen;
unsigned long *optr;
unsigned long subid;
vlen += 1;
if (vlen < 2 || vlen > UINT_MAX / sizeof(unsigned long))
goto fail_nullify;
*oid = kmalloc(vlen * sizeof(unsigned long), GFP_KERNEL);
if (!*oid)
return false;
optr = *oid;
if (!asn1_subid_decode(&iptr, end, &subid))
goto fail;
if (subid < 40) {
optr[0] = 0;
optr[1] = subid;
} else if (subid < 80) {
optr[0] = 1;
optr[1] = subid - 40;
} else {
optr[0] = 2;
optr[1] = subid - 80;
}
*oidlen = 2;
optr += 2;
while (iptr < end) {
if (++(*oidlen) > vlen)
goto fail;
if (!asn1_subid_decode(&iptr, end, optr++))
goto fail;
}
return true;
fail:
kfree(*oid);
fail_nullify:
*oid = NULL;
return false;
}
static bool oid_eq(unsigned long *oid1, unsigned int oid1len,
unsigned long *oid2, unsigned int oid2len)
{
if (oid1len != oid2len)
return false;
return memcmp(oid1, oid2, oid1len) == 0;
}
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)
{
unsigned long *oid;
size_t oidlen;
int err = 0;
if (!asn1_oid_decode(value, vlen, &oid, &oidlen)) {
err = -EBADMSG;
goto out;
}
if (!oid_eq(oid, oidlen, SPNEGO_OID, SPNEGO_OID_LEN))
err = -EBADMSG;
kfree(oid);
out:
if (err) {
char buf[50];
sprint_oid(value, vlen, buf, sizeof(buf));
ksmbd_debug(AUTH, "Unexpected OID: %s\n", buf);
}
return err;
}
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;
unsigned long *oid;
size_t oidlen;
int mech_type;
char buf[50];
if (!asn1_oid_decode(value, vlen, &oid, &oidlen))
goto fail;
if (oid_eq(oid, oidlen, NTLMSSP_OID, NTLMSSP_OID_LEN))
mech_type = KSMBD_AUTH_NTLMSSP;
else if (oid_eq(oid, oidlen, MSKRB5_OID, MSKRB5_OID_LEN))
mech_type = KSMBD_AUTH_MSKRB5;
else if (oid_eq(oid, oidlen, KRB5_OID, KRB5_OID_LEN))
mech_type = KSMBD_AUTH_KRB5;
else if (oid_eq(oid, oidlen, KRB5U2U_OID, KRB5U2U_OID_LEN))
mech_type = KSMBD_AUTH_KRB5U2U;
else
goto fail;
conn->auth_mechs |= mech_type;
if (conn->preferred_auth_mech == 0)
conn->preferred_auth_mech = mech_type;
kfree(oid);
return 0;
fail:
kfree(oid);
sprint_oid(value, vlen, buf, sizeof(buf));
ksmbd_debug(AUTH, "Unexpected OID: %s\n", buf);
return -EBADMSG;
}
int ksmbd_neg_token_init_mech_token(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_targ_resp_token(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;
}