[linux.git] / fs / cifs / asn1.c

/*
 * 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).
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
 */

#include <linux/module.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include "cifspdu.h"
#include "cifsglob.h"
#include "cifs_debug.h"
#include "cifsproto.h"

/*****************************************************************************
 *
 * Basic ASN.1 decoding routines (gxsnmp author Dirk Wisse)
 *
 *****************************************************************************/

/* Class */
#define ASN1_UNI	0	/* Universal */
#define ASN1_APL	1	/* Application */
#define ASN1_CTX	2	/* Context */
#define ASN1_PRV	3	/* Private */

/* Tag */
#define ASN1_EOC	0	/* End Of Contents or N/A */
#define ASN1_BOL	1	/* Boolean */
#define ASN1_INT	2	/* Integer */
#define ASN1_BTS	3	/* Bit String */
#define ASN1_OTS	4	/* Octet String */
#define ASN1_NUL	5	/* Null */
#define ASN1_OJI	6	/* Object Identifier  */
#define ASN1_OJD	7	/* Object Description */
#define ASN1_EXT	8	/* External */
#define ASN1_ENUM	10	/* Enumerated */
#define ASN1_SEQ	16	/* Sequence */
#define ASN1_SET	17	/* Set */
#define ASN1_NUMSTR	18	/* Numerical String */
#define ASN1_PRNSTR	19	/* Printable String */
#define ASN1_TEXSTR	20	/* Teletext String */
#define ASN1_VIDSTR	21	/* Video String */
#define ASN1_IA5STR	22	/* IA5 String */
#define ASN1_UNITIM	23	/* Universal Time */
#define ASN1_GENTIM	24	/* General Time */
#define ASN1_GRASTR	25	/* Graphical String */
#define ASN1_VISSTR	26	/* Visible String */
#define ASN1_GENSTR	27	/* General String */

/* Primitive / Constructed methods*/
#define ASN1_PRI	0	/* Primitive */
#define ASN1_CON	1	/* Constructed */

/*
 * Error codes.
 */
#define ASN1_ERR_NOERROR		0
#define ASN1_ERR_DEC_EMPTY		2
#define ASN1_ERR_DEC_EOC_MISMATCH	3
#define ASN1_ERR_DEC_LENGTH_MISMATCH	4
#define ASN1_ERR_DEC_BADVALUE		5

#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 };

/*
 * ASN.1 context.
 */
struct asn1_ctx {
	int error;		/* Error condition */
	unsigned char *pointer;	/* Octet just to be decoded */
	unsigned char *begin;	/* First octet */
	unsigned char *end;	/* Octet after last octet */
};

/*
 * Octet string (not null terminated)
 */
struct asn1_octstr {
	unsigned char *data;
	unsigned int len;
};

static void
asn1_open(struct asn1_ctx *ctx, unsigned char *buf, unsigned int len)
{
	ctx->begin = buf;
	ctx->end = buf + len;
	ctx->pointer = buf;
	ctx->error = ASN1_ERR_NOERROR;
}

static unsigned char
asn1_octet_decode(struct asn1_ctx *ctx, unsigned char *ch)
{
	if (ctx->pointer >= ctx->end) {
		ctx->error = ASN1_ERR_DEC_EMPTY;
		return 0;
	}
	*ch = *(ctx->pointer)++;
	return 1;
}

#if 0 /* will be needed later by spnego decoding/encoding of ntlmssp */
static unsigned char
asn1_enum_decode(struct asn1_ctx *ctx, __le32 *val)
{
	unsigned char ch;

	if (ctx->pointer >= ctx->end) {
		ctx->error = ASN1_ERR_DEC_EMPTY;
		return 0;
	}

	ch = *(ctx->pointer)++; /* ch has 0xa, ptr points to lenght octet */
	if ((ch) == ASN1_ENUM)  /* if ch value is ENUM, 0xa */
		*val = *(++(ctx->pointer)); /* value has enum value */
	else
		return 0;

	ctx->pointer++;
	return 1;
}
#endif

static unsigned char
asn1_tag_decode(struct asn1_ctx *ctx, unsigned int *tag)
{
	unsigned char ch;

	*tag = 0;

	do {
		if (!asn1_octet_decode(ctx, &ch))
			return 0;
		*tag <<= 7;
		*tag |= ch & 0x7F;
	} while ((ch & 0x80) == 0x80);
	return 1;
}

static unsigned char
asn1_id_decode(struct asn1_ctx *ctx,
	       unsigned int *cls, unsigned int *con, unsigned int *tag)
{
	unsigned char ch;

	if (!asn1_octet_decode(ctx, &ch))
		return 0;

	*cls = (ch & 0xC0) >> 6;
	*con = (ch & 0x20) >> 5;
	*tag = (ch & 0x1F);

	if (*tag == 0x1F) {
		if (!asn1_tag_decode(ctx, tag))
			return 0;
	}
	return 1;
}

static unsigned char
asn1_length_decode(struct asn1_ctx *ctx, unsigned int *def, unsigned int *len)
{
	unsigned char ch, cnt;

	if (!asn1_octet_decode(ctx, &ch))
		return 0;

	if (ch == 0x80)
		*def = 0;
	else {
		*def = 1;

		if (ch < 0x80)
			*len = ch;
		else {
			cnt = (unsigned char) (ch & 0x7F);
			*len = 0;

			while (cnt > 0) {
				if (!asn1_octet_decode(ctx, &ch))
					return 0;
				*len <<= 8;
				*len |= ch;
				cnt--;
			}
		}
	}

	/* don't trust len bigger than ctx buffer */
	if (*len > ctx->end - ctx->pointer)
		return 0;

	return 1;
}

static unsigned char
asn1_header_decode(struct asn1_ctx *ctx,
		   unsigned char **eoc,
		   unsigned int *cls, unsigned int *con, unsigned int *tag)
{
	unsigned int def = 0;
	unsigned int len = 0;

	if (!asn1_id_decode(ctx, cls, con, tag))
		return 0;

	if (!asn1_length_decode(ctx, &def, &len))
		return 0;

	/* primitive shall be definite, indefinite shall be constructed */
	if (*con == ASN1_PRI && !def)
		return 0;

	if (def)
		*eoc = ctx->pointer + len;
	else
		*eoc = NULL;
	return 1;
}

static unsigned char
asn1_eoc_decode(struct asn1_ctx *ctx, unsigned char *eoc)
{
	unsigned char ch;

	if (eoc == NULL) {
		if (!asn1_octet_decode(ctx, &ch))
			return 0;

		if (ch != 0x00) {
			ctx->error = ASN1_ERR_DEC_EOC_MISMATCH;
			return 0;
		}

		if (!asn1_octet_decode(ctx, &ch))
			return 0;

		if (ch != 0x00) {
			ctx->error = ASN1_ERR_DEC_EOC_MISMATCH;
			return 0;
		}
		return 1;
	} else {
		if (ctx->pointer != eoc) {
			ctx->error = ASN1_ERR_DEC_LENGTH_MISMATCH;
			return 0;
		}
		return 1;
	}
}

/* static unsigned char asn1_null_decode(struct asn1_ctx *ctx,
				      unsigned char *eoc)
{
	ctx->pointer = eoc;
	return 1;
}

static unsigned char asn1_long_decode(struct asn1_ctx *ctx,
				      unsigned char *eoc, long *integer)
{
	unsigned char ch;
	unsigned int len;

	if (!asn1_octet_decode(ctx, &ch))
		return 0;

	*integer = (signed char) ch;
	len = 1;

	while (ctx->pointer < eoc) {
		if (++len > sizeof(long)) {
			ctx->error = ASN1_ERR_DEC_BADVALUE;
			return 0;
		}

		if (!asn1_octet_decode(ctx, &ch))
			return 0;

		*integer <<= 8;
		*integer |= ch;
	}
	return 1;
}

static unsigned char asn1_uint_decode(struct asn1_ctx *ctx,
				      unsigned char *eoc,
				      unsigned int *integer)
{
	unsigned char ch;
	unsigned int len;

	if (!asn1_octet_decode(ctx, &ch))
		return 0;

	*integer = ch;
	if (ch == 0)
		len = 0;
	else
		len = 1;

	while (ctx->pointer < eoc) {
		if (++len > sizeof(unsigned int)) {
			ctx->error = ASN1_ERR_DEC_BADVALUE;
			return 0;
		}

		if (!asn1_octet_decode(ctx, &ch))
			return 0;

		*integer <<= 8;
		*integer |= ch;
	}
	return 1;
}

static unsigned char asn1_ulong_decode(struct asn1_ctx *ctx,
				       unsigned char *eoc,
				       unsigned long *integer)
{
	unsigned char ch;
	unsigned int len;

	if (!asn1_octet_decode(ctx, &ch))
		return 0;

	*integer = ch;
	if (ch == 0)
		len = 0;
	else
		len = 1;

	while (ctx->pointer < eoc) {
		if (++len > sizeof(unsigned long)) {
			ctx->error = ASN1_ERR_DEC_BADVALUE;
			return 0;
		}

		if (!asn1_octet_decode(ctx, &ch))
			return 0;

		*integer <<= 8;
		*integer |= ch;
	}
	return 1;
}

static unsigned char
asn1_octets_decode(struct asn1_ctx *ctx,
		   unsigned char *eoc,
		   unsigned char **octets, unsigned int *len)
{
	unsigned char *ptr;

	*len = 0;

	*octets = kmalloc(eoc - ctx->pointer, GFP_ATOMIC);
	if (*octets == NULL) {
		return 0;
	}

	ptr = *octets;
	while (ctx->pointer < eoc) {
		if (!asn1_octet_decode(ctx, (unsigned char *) ptr++)) {
			kfree(*octets);
			*octets = NULL;
			return 0;
		}
		(*len)++;
	}
	return 1;
} */

static unsigned char
asn1_subid_decode(struct asn1_ctx *ctx, unsigned long *subid)
{
	unsigned char ch;

	*subid = 0;

	do {
		if (!asn1_octet_decode(ctx, &ch))
			return 0;

		*subid <<= 7;
		*subid |= ch & 0x7F;
	} while ((ch & 0x80) == 0x80);
	return 1;
}

static int
asn1_oid_decode(struct asn1_ctx *ctx,
		unsigned char *eoc, unsigned long **oid, unsigned int *len)
{
	unsigned long subid;
	unsigned int size;
	unsigned long *optr;

	size = eoc - ctx->pointer + 1;

	/* first subid actually encodes first two subids */
	if (size < 2 || size > UINT_MAX/sizeof(unsigned long))
		return 0;

	*oid = kmalloc(size * sizeof(unsigned long), GFP_ATOMIC);
	if (*oid == NULL)
		return 0;

	optr = *oid;

	if (!asn1_subid_decode(ctx, &subid)) {
		kfree(*oid);
		*oid = NULL;
		return 0;
	}

	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;
	}

	*len = 2;
	optr += 2;

	while (ctx->pointer < eoc) {
		if (++(*len) > size) {
			ctx->error = ASN1_ERR_DEC_BADVALUE;
			kfree(*oid);
			*oid = NULL;
			return 0;
		}

		if (!asn1_subid_decode(ctx, optr++)) {
			kfree(*oid);
			*oid = NULL;
			return 0;
		}
	}
	return 1;
}

static int
compare_oid(unsigned long *oid1, unsigned int oid1len,
	    unsigned long *oid2, unsigned int oid2len)
{
	unsigned int i;

	if (oid1len != oid2len)
		return 0;
	else {
		for (i = 0; i < oid1len; i++) {
			if (oid1[i] != oid2[i])
				return 0;
		}
		return 1;
	}
}

	/* BB check for endian conversion issues here */

int
decode_negTokenInit(unsigned char *security_blob, int length,
		    enum securityEnum *secType)
{
	struct asn1_ctx ctx;
	unsigned char *end;
	unsigned char *sequence_end;
	unsigned long *oid = NULL;
	unsigned int cls, con, tag, oidlen, rc;
	bool use_ntlmssp = false;
	bool use_kerberos = false;
	bool use_kerberosu2u = false;
	bool use_mskerberos = false;

	/* cifs_dump_mem(" Received SecBlob ", security_blob, length); */

	asn1_open(&ctx, security_blob, length);

	/* GSSAPI header */
	if (asn1_header_decode(&ctx, &end, &cls, &con, &tag) == 0) {
		cFYI(1, ("Error decoding negTokenInit header"));
		return 0;
	} else if ((cls != ASN1_APL) || (con != ASN1_CON)
		   || (tag != ASN1_EOC)) {
		cFYI(1, ("cls = %d con = %d tag = %d", cls, con, tag));
		return 0;
	}

	/* Check for SPNEGO OID -- remember to free obj->oid */
	rc = asn1_header_decode(&ctx, &end, &cls, &con, &tag);
	if (rc) {
		if ((tag == ASN1_OJI) && (con == ASN1_PRI) &&
		    (cls == ASN1_UNI)) {
			rc = asn1_oid_decode(&ctx, end, &oid, &oidlen);
			if (rc) {
				rc = compare_oid(oid, oidlen, SPNEGO_OID,
						 SPNEGO_OID_LEN);
				kfree(oid);
			}
		} else
			rc = 0;
	}

	/* SPNEGO OID not present or garbled -- bail out */
	if (!rc) {
		cFYI(1, ("Error decoding negTokenInit header"));
		return 0;
	}

	/* SPNEGO */
	if (asn1_header_decode(&ctx, &end, &cls, &con, &tag) == 0) {
		cFYI(1, ("Error decoding negTokenInit"));
		return 0;
	} else if ((cls != ASN1_CTX) || (con != ASN1_CON)
		   || (tag != ASN1_EOC)) {
		cFYI(1,
		     ("cls = %d con = %d tag = %d end = %p (%d) exit 0",
		      cls, con, tag, end, *end));
		return 0;
	}

	/* negTokenInit */
	if (asn1_header_decode(&ctx, &end, &cls, &con, &tag) == 0) {
		cFYI(1, ("Error decoding negTokenInit"));
		return 0;
	} else if ((cls != ASN1_UNI) || (con != ASN1_CON)
		   || (tag != ASN1_SEQ)) {
		cFYI(1,
		     ("cls = %d con = %d tag = %d end = %p (%d) exit 1",
		      cls, con, tag, end, *end));
		return 0;
	}

	/* sequence */
	if (asn1_header_decode(&ctx, &end, &cls, &con, &tag) == 0) {
		cFYI(1, ("Error decoding 2nd part of negTokenInit"));
		return 0;
	} else if ((cls != ASN1_CTX) || (con != ASN1_CON)
		   || (tag != ASN1_EOC)) {
		cFYI(1,
		     ("cls = %d con = %d tag = %d end = %p (%d) exit 0",
		      cls, con, tag, end, *end));
		return 0;
	}

	/* sequence of */
	if (asn1_header_decode
	    (&ctx, &sequence_end, &cls, &con, &tag) == 0) {
		cFYI(1, ("Error decoding 2nd part of negTokenInit"));
		return 0;
	} else if ((cls != ASN1_UNI) || (con != ASN1_CON)
		   || (tag != ASN1_SEQ)) {
		cFYI(1,
		     ("cls = %d con = %d tag = %d end = %p (%d) exit 1",
		      cls, con, tag, end, *end));
		return 0;
	}

	/* list of security mechanisms */
	while (!asn1_eoc_decode(&ctx, sequence_end)) {
		rc = asn1_header_decode(&ctx, &end, &cls, &con, &tag);
		if (!rc) {
			cFYI(1,
			     ("Error decoding negTokenInit hdr exit2"));
			return 0;
		}
		if ((tag == ASN1_OJI) && (con == ASN1_PRI)) {
			if (asn1_oid_decode(&ctx, end, &oid, &oidlen)) {

				cFYI(1, ("OID len = %d oid = 0x%lx 0x%lx "
					 "0x%lx 0x%lx", oidlen, *oid,
					 *(oid + 1), *(oid + 2), *(oid + 3)));

				if (compare_oid(oid, oidlen, MSKRB5_OID,
						MSKRB5_OID_LEN) &&
						!use_mskerberos)
					use_mskerberos = true;
				else if (compare_oid(oid, oidlen, KRB5U2U_OID,
						     KRB5U2U_OID_LEN) &&
						     !use_kerberosu2u)
					use_kerberosu2u = true;
				else if (compare_oid(oid, oidlen, KRB5_OID,
						     KRB5_OID_LEN) &&
						     !use_kerberos)
					use_kerberos = true;
				else if (compare_oid(oid, oidlen, NTLMSSP_OID,
						     NTLMSSP_OID_LEN))
					use_ntlmssp = true;

				kfree(oid);
			}
		} else {
			cFYI(1, ("Should be an oid what is going on?"));
		}
	}

	/* mechlistMIC */
	if (asn1_header_decode(&ctx, &end, &cls, &con, &tag) == 0) {
		/* Check if we have reached the end of the blob, but with
		   no mechListMic (e.g. NTLMSSP instead of KRB5) */
		if (ctx.error == ASN1_ERR_DEC_EMPTY)
			goto decode_negtoken_exit;
		cFYI(1, ("Error decoding last part negTokenInit exit3"));
		return 0;
	} else if ((cls != ASN1_CTX) || (con != ASN1_CON)) {
		/* tag = 3 indicating mechListMIC */
		cFYI(1, ("Exit 4 cls = %d con = %d tag = %d end = %p (%d)",
			 cls, con, tag, end, *end));
		return 0;
	}

	/* sequence */
	if (asn1_header_decode(&ctx, &end, &cls, &con, &tag) == 0) {
		cFYI(1, ("Error decoding last part negTokenInit exit5"));
		return 0;
	} else if ((cls != ASN1_UNI) || (con != ASN1_CON)
		   || (tag != ASN1_SEQ)) {
		cFYI(1, ("cls = %d con = %d tag = %d end = %p (%d)",
			cls, con, tag, end, *end));
	}

	/* sequence of */
	if (asn1_header_decode(&ctx, &end, &cls, &con, &tag) == 0) {
		cFYI(1, ("Error decoding last part negTokenInit exit 7"));
		return 0;
	} else if ((cls != ASN1_CTX) || (con != ASN1_CON)) {
		cFYI(1, ("Exit 8 cls = %d con = %d tag = %d end = %p (%d)",
			 cls, con, tag, end, *end));
		return 0;
	}

	/* general string */
	if (asn1_header_decode(&ctx, &end, &cls, &con, &tag) == 0) {
		cFYI(1, ("Error decoding last part negTokenInit exit9"));
		return 0;
	} else if ((cls != ASN1_UNI) || (con != ASN1_PRI)
		   || (tag != ASN1_GENSTR)) {
		cFYI(1, ("Exit10 cls = %d con = %d tag = %d end = %p (%d)",
			 cls, con, tag, end, *end));
		return 0;
	}
	cFYI(1, ("Need to call asn1_octets_decode() function for %s",
		 ctx.pointer));	/* is this UTF-8 or ASCII? */
decode_negtoken_exit:
	if (use_kerberos)
		*secType = Kerberos;
	else if (use_mskerberos)
		*secType = MSKerberos;
	else if (use_ntlmssp)
		*secType = RawNTLMSSP;

	return 1;
}
Commit	Line	Data
50c2f753	1	/*
1da177e4 LT	2	* The ASB.1/BER parsing code is derived from ip_nat_snmp_basic.c which was in
1da177e4 LT	3	* turn derived from the gxsnmp package by Gregory McLean & Jochen Friedrich
50c2f753	4	*
1da177e4 LT	5	* Copyright (c) 2000 RP Internet (www.rpi.net.au).
	6	*
	7	* This program is free software; you can redistribute it and/or modify
	8	* it under the terms of the GNU General Public License as published by
	9	* the Free Software Foundation; either version 2 of the License, or
	10	* (at your option) any later version.
	11	* This program is distributed in the hope that it will be useful,
	12	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	13	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	14	* GNU General Public License for more details.
	15	* You should have received a copy of the GNU General Public License
	16	* along with this program; if not, write to the Free Software
	17	* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
	18	*/
	19
1da177e4 LT	20	#include <linux/module.h>
	21	#include <linux/types.h>
	22	#include <linux/kernel.h>
	23	#include <linux/mm.h>
	24	#include <linux/slab.h>
	25	#include "cifspdu.h"
	26	#include "cifsglob.h"
	27	#include "cifs_debug.h"
	28	#include "cifsproto.h"
	29
	30	/*****************************************************************************
	31	*
	32	* Basic ASN.1 decoding routines (gxsnmp author Dirk Wisse)
	33	*
	34	*****************************************************************************/
	35
	36	/* Class */
	37	#define ASN1_UNI 0 /* Universal */
	38	#define ASN1_APL 1 /* Application */
	39	#define ASN1_CTX 2 /* Context */
	40	#define ASN1_PRV 3 /* Private */
	41
	42	/* Tag */
	43	#define ASN1_EOC 0 /* End Of Contents or N/A */
	44	#define ASN1_BOL 1 /* Boolean */
	45	#define ASN1_INT 2 /* Integer */
	46	#define ASN1_BTS 3 /* Bit String */
	47	#define ASN1_OTS 4 /* Octet String */
	48	#define ASN1_NUL 5 /* Null */
	49	#define ASN1_OJI 6 /* Object Identifier */
	50	#define ASN1_OJD 7 /* Object Description */
	51	#define ASN1_EXT 8 /* External */
f46c7234	52	#define ASN1_ENUM 10 /* Enumerated */
1da177e4 LT	53	#define ASN1_SEQ 16 /* Sequence */
	54	#define ASN1_SET 17 /* Set */
	55	#define ASN1_NUMSTR 18 /* Numerical String */
	56	#define ASN1_PRNSTR 19 /* Printable String */
	57	#define ASN1_TEXSTR 20 /* Teletext String */
	58	#define ASN1_VIDSTR 21 /* Video String */
	59	#define ASN1_IA5STR 22 /* IA5 String */
	60	#define ASN1_UNITIM 23 /* Universal Time */
	61	#define ASN1_GENTIM 24 /* General Time */
	62	#define ASN1_GRASTR 25 /* Graphical String */
	63	#define ASN1_VISSTR 26 /* Visible String */
	64	#define ASN1_GENSTR 27 /* General String */
	65
	66	/* Primitive / Constructed methods*/
	67	#define ASN1_PRI 0 /* Primitive */
	68	#define ASN1_CON 1 /* Constructed */
	69
	70	/*
	71	* Error codes.
	72	*/
	73	#define ASN1_ERR_NOERROR 0
	74	#define ASN1_ERR_DEC_EMPTY 2
	75	#define ASN1_ERR_DEC_EOC_MISMATCH 3
	76	#define ASN1_ERR_DEC_LENGTH_MISMATCH 4
	77	#define ASN1_ERR_DEC_BADVALUE 5
	78
	79	#define SPNEGO_OID_LEN 7
	80	#define NTLMSSP_OID_LEN 10
e545937a	81	#define KRB5_OID_LEN 7
f46c7234	82	#define KRB5U2U_OID_LEN 8
e545937a	83	#define MSKRB5_OID_LEN 7
1da177e4 LT	84	static unsigned long SPNEGO_OID[7] = { 1, 3, 6, 1, 5, 5, 2 };
1da177e4 LT	85	static unsigned long NTLMSSP_OID[10] = { 1, 3, 6, 1, 4, 1, 311, 2, 2, 10 };
e545937a	86	static unsigned long KRB5_OID[7] = { 1, 2, 840, 113554, 1, 2, 2 };
f46c7234	87	static unsigned long KRB5U2U_OID[8] = { 1, 2, 840, 113554, 1, 2, 2, 3 };
e545937a	88	static unsigned long MSKRB5_OID[7] = { 1, 2, 840, 48018, 1, 2, 2 };
1da177e4	89
50c2f753	90	/*
1da177e4 LT	91	* ASN.1 context.
	92	*/
	93	struct asn1_ctx {
	94	int error; /* Error condition */
	95	unsigned char pointer; / Octet just to be decoded */
	96	unsigned char begin; / First octet */
	97	unsigned char end; / Octet after last octet */
	98	};
	99
	100	/*
	101	* Octet string (not null terminated)
	102	*/
	103	struct asn1_octstr {
	104	unsigned char *data;
	105	unsigned int len;
	106	};
	107
	108	static void
	109	asn1_open(struct asn1_ctx ctx, unsigned char buf, unsigned int len)
	110	{
	111	ctx->begin = buf;
	112	ctx->end = buf + len;
	113	ctx->pointer = buf;
	114	ctx->error = ASN1_ERR_NOERROR;
	115	}
	116
	117	static unsigned char
	118	asn1_octet_decode(struct asn1_ctx ctx, unsigned char ch)
	119	{
	120	if (ctx->pointer >= ctx->end) {
	121	ctx->error = ASN1_ERR_DEC_EMPTY;
	122	return 0;
	123	}
	124	ch = (ctx->pointer)++;
	125	return 1;
	126	}
	127
f46c7234 SF	128	#if 0 /* will be needed later by spnego decoding/encoding of ntlmssp */
	129	static unsigned char
	130	asn1_enum_decode(struct asn1_ctx ctx, __le32 val)
	131	{
	132	unsigned char ch;
	133
	134	if (ctx->pointer >= ctx->end) {
	135	ctx->error = ASN1_ERR_DEC_EMPTY;
	136	return 0;
	137	}
	138
	139	ch = (ctx->pointer)++; / ch has 0xa, ptr points to lenght octet */
	140	if ((ch) == ASN1_ENUM) /* if ch value is ENUM, 0xa */
	141	val = (++(ctx->pointer)); /* value has enum value */
	142	else
	143	return 0;
	144
	145	ctx->pointer++;
	146	return 1;
	147	}
	148	#endif
	149
1da177e4 LT	150	static unsigned char
	151	asn1_tag_decode(struct asn1_ctx ctx, unsigned int tag)
	152	{
	153	unsigned char ch;
	154
	155	*tag = 0;
	156
	157	do {
	158	if (!asn1_octet_decode(ctx, &ch))
	159	return 0;
	160	*tag <<= 7;
	161	*tag \|= ch & 0x7F;
	162	} while ((ch & 0x80) == 0x80);
	163	return 1;
	164	}
	165
	166	static unsigned char
	167	asn1_id_decode(struct asn1_ctx *ctx,
	168	unsigned int cls, unsigned int con, unsigned int *tag)
	169	{
	170	unsigned char ch;
	171
	172	if (!asn1_octet_decode(ctx, &ch))
	173	return 0;
	174
	175	*cls = (ch & 0xC0) >> 6;
	176	*con = (ch & 0x20) >> 5;
	177	*tag = (ch & 0x1F);
	178
	179	if (*tag == 0x1F) {
	180	if (!asn1_tag_decode(ctx, tag))
	181	return 0;
	182	}
	183	return 1;
	184	}
	185
	186	static unsigned char
	187	asn1_length_decode(struct asn1_ctx ctx, unsigned int def, unsigned int *len)
	188	{
	189	unsigned char ch, cnt;
	190
	191	if (!asn1_octet_decode(ctx, &ch))
	192	return 0;
	193
	194	if (ch == 0x80)
	195	*def = 0;
	196	else {
	197	*def = 1;
	198
	199	if (ch < 0x80)
	200	*len = ch;
	201	else {
	202	cnt = (unsigned char) (ch & 0x7F);
	203	*len = 0;
	204
	205	while (cnt > 0) {
	206	if (!asn1_octet_decode(ctx, &ch))
	207	return 0;
	208	*len <<= 8;
	209	*len \|= ch;
	210	cnt--;
	211	}
	212	}
	213	}
ddb2c435 CW	214
	215	/* don't trust len bigger than ctx buffer */
	216	if (*len > ctx->end - ctx->pointer)
	217	return 0;
	218
1da177e4 LT	219	return 1;
	220	}
	221
	222	static unsigned char
	223	asn1_header_decode(struct asn1_ctx *ctx,
	224	unsigned char **eoc,
	225	unsigned int cls, unsigned int con, unsigned int *tag)
	226	{
50c2f753	227	unsigned int def = 0;
ab2f218f	228	unsigned int len = 0;
1da177e4 LT	229
	230	if (!asn1_id_decode(ctx, cls, con, tag))
	231	return 0;
	232
	233	if (!asn1_length_decode(ctx, &def, &len))
	234	return 0;
	235
ddb2c435 CW	236	/* primitive shall be definite, indefinite shall be constructed */
	237	if (*con == ASN1_PRI && !def)
	238	return 0;
	239
1da177e4 LT	240	if (def)
	241	*eoc = ctx->pointer + len;
	242	else
	243	*eoc = NULL;
	244	return 1;
	245	}
	246
	247	static unsigned char
	248	asn1_eoc_decode(struct asn1_ctx ctx, unsigned char eoc)
	249	{
	250	unsigned char ch;
	251
	252	if (eoc == NULL) {
	253	if (!asn1_octet_decode(ctx, &ch))
	254	return 0;
	255
	256	if (ch != 0x00) {
	257	ctx->error = ASN1_ERR_DEC_EOC_MISMATCH;
	258	return 0;
	259	}
	260
	261	if (!asn1_octet_decode(ctx, &ch))
	262	return 0;
	263
	264	if (ch != 0x00) {
	265	ctx->error = ASN1_ERR_DEC_EOC_MISMATCH;
	266	return 0;
	267	}
	268	return 1;
	269	} else {
	270	if (ctx->pointer != eoc) {
	271	ctx->error = ASN1_ERR_DEC_LENGTH_MISMATCH;
	272	return 0;
	273	}
	274	return 1;
	275	}
	276	}
	277
	278	/* static unsigned char asn1_null_decode(struct asn1_ctx *ctx,
	279	unsigned char *eoc)
	280	{
	281	ctx->pointer = eoc;
	282	return 1;
	283	}
	284
	285	static unsigned char asn1_long_decode(struct asn1_ctx *ctx,
	286	unsigned char eoc, long integer)
	287	{
	288	unsigned char ch;
	289	unsigned int len;
	290
	291	if (!asn1_octet_decode(ctx, &ch))
	292	return 0;
	293
	294	*integer = (signed char) ch;
	295	len = 1;
	296
	297	while (ctx->pointer < eoc) {
	298	if (++len > sizeof(long)) {
	299	ctx->error = ASN1_ERR_DEC_BADVALUE;
	300	return 0;
	301	}
	302
	303	if (!asn1_octet_decode(ctx, &ch))
304	return 0;
305
306	*integer <<= 8;
307	*integer \|= ch;
308	}
309	return 1;
310	}
311
312	static unsigned char asn1_uint_decode(struct asn1_ctx *ctx,
313	unsigned char *eoc,
314	unsigned int *integer)
315	{
316	unsigned char ch;
317	unsigned int len;
318
319	if (!asn1_octet_decode(ctx, &ch))
320	return 0;
321
322	*integer = ch;
323	if (ch == 0)
324	len = 0;
325	else
326	len = 1;
327
328	while (ctx->pointer < eoc) {
329	if (++len > sizeof(unsigned int)) {
330	ctx->error = ASN1_ERR_DEC_BADVALUE;
331	return 0;
332	}
333
334	if (!asn1_octet_decode(ctx, &ch))
335	return 0;
336
337	*integer <<= 8;
338	*integer \|= ch;
339	}
340	return 1;
341	}
342
343	static unsigned char asn1_ulong_decode(struct asn1_ctx *ctx,
344	unsigned char *eoc,
345	unsigned long *integer)
346	{
347	unsigned char ch;
348	unsigned int len;
349
350	if (!asn1_octet_decode(ctx, &ch))
351	return 0;
352
353	*integer = ch;
354	if (ch == 0)
355	len = 0;
356	else
357	len = 1;
358
359	while (ctx->pointer < eoc) {
360	if (++len > sizeof(unsigned long)) {
361	ctx->error = ASN1_ERR_DEC_BADVALUE;
362	return 0;
363	}
364
365	if (!asn1_octet_decode(ctx, &ch))
366	return 0;
367
368	*integer <<= 8;
369	*integer \|= ch;
370	}
371	return 1;
50c2f753	372	}
1da177e4 LT	373
	374	static unsigned char
	375	asn1_octets_decode(struct asn1_ctx *ctx,
	376	unsigned char *eoc,
	377	unsigned char *octets, unsigned int len)
	378	{
	379	unsigned char *ptr;
	380
	381	*len = 0;
	382
	383	*octets = kmalloc(eoc - ctx->pointer, GFP_ATOMIC);
	384	if (*octets == NULL) {
	385	return 0;
	386	}
	387
	388	ptr = *octets;
	389	while (ctx->pointer < eoc) {
	390	if (!asn1_octet_decode(ctx, (unsigned char *) ptr++)) {
	391	kfree(*octets);
	392	*octets = NULL;
	393	return 0;
	394	}
	395	(*len)++;
	396	}
	397	return 1;
	398	} */
	399
	400	static unsigned char
	401	asn1_subid_decode(struct asn1_ctx ctx, unsigned long subid)
	402	{
	403	unsigned char ch;
	404
	405	*subid = 0;
	406
	407	do {
	408	if (!asn1_octet_decode(ctx, &ch))
	409	return 0;
	410
	411	*subid <<= 7;
	412	*subid \|= ch & 0x7F;
	413	} while ((ch & 0x80) == 0x80);
	414	return 1;
	415	}
	416
50c2f753	417	static int
1da177e4 LT	418	asn1_oid_decode(struct asn1_ctx *ctx,
	419	unsigned char eoc, unsigned long oid, unsigned int len)
	420	{
	421	unsigned long subid;
	422	unsigned int size;
	423	unsigned long *optr;
	424
	425	size = eoc - ctx->pointer + 1;
ddb2c435 CW	426
ddb2c435 CW	427	/* first subid actually encodes first two subids */
04e1e0cc	428	if (size < 2 \|\| size > UINT_MAX/sizeof(unsigned long))
ddb2c435 CW	429	return 0;
ddb2c435 CW	430
26f57364 SF	431	oid = kmalloc(size sizeof(unsigned long), GFP_ATOMIC);
26f57364 SF	432	if (*oid == NULL)
1da177e4	433	return 0;
1da177e4 LT	434
	435	optr = *oid;
	436
	437	if (!asn1_subid_decode(ctx, &subid)) {
	438	kfree(*oid);
	439	*oid = NULL;
	440	return 0;
	441	}
	442
	443	if (subid < 40) {
	444	optr[0] = 0;
	445	optr[1] = subid;
	446	} else if (subid < 80) {
	447	optr[0] = 1;
	448	optr[1] = subid - 40;
	449	} else {
	450	optr[0] = 2;
	451	optr[1] = subid - 80;
	452	}
	453
	454	*len = 2;
	455	optr += 2;
	456
	457	while (ctx->pointer < eoc) {
	458	if (++(*len) > size) {
	459	ctx->error = ASN1_ERR_DEC_BADVALUE;
	460	kfree(*oid);
	461	*oid = NULL;
	462	return 0;
	463	}
	464
	465	if (!asn1_subid_decode(ctx, optr++)) {
	466	kfree(*oid);
	467	*oid = NULL;
	468	return 0;
	469	}
	470	}
	471	return 1;
	472	}
	473
	474	static int
	475	compare_oid(unsigned long *oid1, unsigned int oid1len,
	476	unsigned long *oid2, unsigned int oid2len)
	477	{
	478	unsigned int i;
	479
	480	if (oid1len != oid2len)
	481	return 0;
	482	else {
	483	for (i = 0; i < oid1len; i++) {
	484	if (oid1[i] != oid2[i])
	485	return 0;
	486	}
	487	return 1;
	488	}
	489	}
	490
	491	/* BB check for endian conversion issues here */
	492
	493	int
	494	decode_negTokenInit(unsigned char *security_blob, int length,
	495	enum securityEnum *secType)
	496	{
	497	struct asn1_ctx ctx;
498	unsigned char *end;
499	unsigned char *sequence_end;
500	unsigned long *oid = NULL;
501	unsigned int cls, con, tag, oidlen, rc;
4b18f2a9 SF	502	bool use_ntlmssp = false;
4b18f2a9 SF	503	bool use_kerberos = false;
f46c7234	504	bool use_kerberosu2u = false;
c16fefa5	505	bool use_mskerberos = false;
1da177e4	506
1da177e4 LT	507	/* cifs_dump_mem(" Received SecBlob ", security_blob, length); */
	508
	509	asn1_open(&ctx, security_blob, length);
	510
2f0e58ac	511	/* GSSAPI header */
1da177e4	512	if (asn1_header_decode(&ctx, &end, &cls, &con, &tag) == 0) {
26a21b98	513	cFYI(1, ("Error decoding negTokenInit header"));
1da177e4 LT	514	return 0;
	515	} else if ((cls != ASN1_APL) \|\| (con != ASN1_CON)
	516	\|\| (tag != ASN1_EOC)) {
	517	cFYI(1, ("cls = %d con = %d tag = %d", cls, con, tag));
	518	return 0;
2f0e58ac	519	}
1da177e4	520
2f0e58ac JL	521	/* Check for SPNEGO OID -- remember to free obj->oid */
	522	rc = asn1_header_decode(&ctx, &end, &cls, &con, &tag);
	523	if (rc) {
	524	if ((tag == ASN1_OJI) && (con == ASN1_PRI) &&
	525	(cls == ASN1_UNI)) {
	526	rc = asn1_oid_decode(&ctx, end, &oid, &oidlen);
	527	if (rc) {
	528	rc = compare_oid(oid, oidlen, SPNEGO_OID,
	529	SPNEGO_OID_LEN);
	530	kfree(oid);
	531	}
	532	} else
	533	rc = 0;
	534	}
1da177e4	535
2f0e58ac JL	536	/* SPNEGO OID not present or garbled -- bail out */
	537	if (!rc) {
	538	cFYI(1, ("Error decoding negTokenInit header"));
	539	return 0;
	540	}
1da177e4	541
f46c7234	542	/* SPNEGO */
2f0e58ac JL	543	if (asn1_header_decode(&ctx, &end, &cls, &con, &tag) == 0) {
	544	cFYI(1, ("Error decoding negTokenInit"));
	545	return 0;
	546	} else if ((cls != ASN1_CTX) \|\| (con != ASN1_CON)
	547	\|\| (tag != ASN1_EOC)) {
	548	cFYI(1,
	549	("cls = %d con = %d tag = %d end = %p (%d) exit 0",
	550	cls, con, tag, end, *end));
	551	return 0;
	552	}
1da177e4	553
f46c7234	554	/* negTokenInit */
2f0e58ac JL	555	if (asn1_header_decode(&ctx, &end, &cls, &con, &tag) == 0) {
	556	cFYI(1, ("Error decoding negTokenInit"));
	557	return 0;
	558	} else if ((cls != ASN1_UNI) \|\| (con != ASN1_CON)
	559	\|\| (tag != ASN1_SEQ)) {
	560	cFYI(1,
	561	("cls = %d con = %d tag = %d end = %p (%d) exit 1",
	562	cls, con, tag, end, *end));
	563	return 0;
	564	}
1da177e4	565
f46c7234	566	/* sequence */
2f0e58ac JL	567	if (asn1_header_decode(&ctx, &end, &cls, &con, &tag) == 0) {
	568	cFYI(1, ("Error decoding 2nd part of negTokenInit"));
	569	return 0;
	570	} else if ((cls != ASN1_CTX) \|\| (con != ASN1_CON)
	571	\|\| (tag != ASN1_EOC)) {
	572	cFYI(1,
	573	("cls = %d con = %d tag = %d end = %p (%d) exit 0",
	574	cls, con, tag, end, *end));
	575	return 0;
	576	}
1da177e4	577
f46c7234	578	/* sequence of */
2f0e58ac JL	579	if (asn1_header_decode
	580	(&ctx, &sequence_end, &cls, &con, &tag) == 0) {
	581	cFYI(1, ("Error decoding 2nd part of negTokenInit"));
	582	return 0;
	583	} else if ((cls != ASN1_UNI) \|\| (con != ASN1_CON)
	584	\|\| (tag != ASN1_SEQ)) {
	585	cFYI(1,
	586	("cls = %d con = %d tag = %d end = %p (%d) exit 1",
	587	cls, con, tag, end, *end));
	588	return 0;
	589	}
1da177e4	590
f46c7234	591	/* list of security mechanisms */
2f0e58ac JL	592	while (!asn1_eoc_decode(&ctx, sequence_end)) {
	593	rc = asn1_header_decode(&ctx, &end, &cls, &con, &tag);
	594	if (!rc) {
1da177e4	595	cFYI(1,
2f0e58ac	596	("Error decoding negTokenInit hdr exit2"));
1da177e4 LT	597	return 0;
1da177e4 LT	598	}
2f0e58ac JL	599	if ((tag == ASN1_OJI) && (con == ASN1_PRI)) {
	600	if (asn1_oid_decode(&ctx, end, &oid, &oidlen)) {
	601
	602	cFYI(1, ("OID len = %d oid = 0x%lx 0x%lx "
	603	"0x%lx 0x%lx", oidlen, *oid,
	604	(oid + 1), (oid + 2), *(oid + 3)));
	605
	606	if (compare_oid(oid, oidlen, MSKRB5_OID,
c16fefa5	607	MSKRB5_OID_LEN) &&
f46c7234	608	!use_mskerberos)
c16fefa5	609	use_mskerberos = true;
f46c7234 SF	610	else if (compare_oid(oid, oidlen, KRB5U2U_OID,
	611	KRB5U2U_OID_LEN) &&
	612	!use_kerberosu2u)
	613	use_kerberosu2u = true;
2f0e58ac	614	else if (compare_oid(oid, oidlen, KRB5_OID,
c16fefa5	615	KRB5_OID_LEN) &&
f46c7234	616	!use_kerberos)
2f0e58ac JL	617	use_kerberos = true;
	618	else if (compare_oid(oid, oidlen, NTLMSSP_OID,
	619	NTLMSSP_OID_LEN))
	620	use_ntlmssp = true;
	621
	622	kfree(oid);
	623	}
	624	} else {
	625	cFYI(1, ("Should be an oid what is going on?"));
1da177e4	626	}
2f0e58ac	627	}
1da177e4	628
f46c7234	629	/* mechlistMIC */
2f0e58ac	630	if (asn1_header_decode(&ctx, &end, &cls, &con, &tag) == 0) {
f46c7234 SF	631	/* Check if we have reached the end of the blob, but with
	632	no mechListMic (e.g. NTLMSSP instead of KRB5) */
	633	if (ctx.error == ASN1_ERR_DEC_EMPTY)
	634	goto decode_negtoken_exit;
2f0e58ac JL	635	cFYI(1, ("Error decoding last part negTokenInit exit3"));
	636	return 0;
	637	} else if ((cls != ASN1_CTX) \|\| (con != ASN1_CON)) {
	638	/* tag = 3 indicating mechListMIC */
	639	cFYI(1, ("Exit 4 cls = %d con = %d tag = %d end = %p (%d)",
	640	cls, con, tag, end, *end));
	641	return 0;
	642	}
f46c7234 SF	643
f46c7234 SF	644	/* sequence */
2f0e58ac JL	645	if (asn1_header_decode(&ctx, &end, &cls, &con, &tag) == 0) {
	646	cFYI(1, ("Error decoding last part negTokenInit exit5"));
	647	return 0;
	648	} else if ((cls != ASN1_UNI) \|\| (con != ASN1_CON)
	649	\|\| (tag != ASN1_SEQ)) {
	650	cFYI(1, ("cls = %d con = %d tag = %d end = %p (%d)",
	651	cls, con, tag, end, *end));
	652	}
	653
f46c7234	654	/* sequence of */
2f0e58ac JL	655	if (asn1_header_decode(&ctx, &end, &cls, &con, &tag) == 0) {
	656	cFYI(1, ("Error decoding last part negTokenInit exit 7"));
	657	return 0;
	658	} else if ((cls != ASN1_CTX) \|\| (con != ASN1_CON)) {
	659	cFYI(1, ("Exit 8 cls = %d con = %d tag = %d end = %p (%d)",
	660	cls, con, tag, end, *end));
	661	return 0;
	662	}
f46c7234 SF	663
f46c7234 SF	664	/* general string */
2f0e58ac JL	665	if (asn1_header_decode(&ctx, &end, &cls, &con, &tag) == 0) {
	666	cFYI(1, ("Error decoding last part negTokenInit exit9"));
	667	return 0;
	668	} else if ((cls != ASN1_UNI) \|\| (con != ASN1_PRI)
	669	\|\| (tag != ASN1_GENSTR)) {
	670	cFYI(1, ("Exit10 cls = %d con = %d tag = %d end = %p (%d)",
	671	cls, con, tag, end, *end));
	672	return 0;
1da177e4	673	}
2f0e58ac JL	674	cFYI(1, ("Need to call asn1_octets_decode() function for %s",
2f0e58ac JL	675	ctx.pointer)); /* is this UTF-8 or ASCII? */
f46c7234	676	decode_negtoken_exit:
e545937a JL	677	if (use_kerberos)
e545937a JL	678	*secType = Kerberos;
c16fefa5 SF	679	else if (use_mskerberos)
c16fefa5 SF	680	*secType = MSKerberos;
e545937a	681	else if (use_ntlmssp)
f46c7234	682	*secType = RawNTLMSSP;
1da177e4 LT	683
	684	return 1;
	685	}