[linux-2.6-block.git] / fs / cifs / asn1.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 "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 length 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_array(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,
		    struct TCP_Server_Info *server)
{
	struct asn1_ctx ctx;
	unsigned char *end;
	unsigned char *sequence_end;
	unsigned long *oid = NULL;
	unsigned int cls, con, tag, oidlen, rc;

	/* 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) {
		cifs_dbg(FYI, "Error decoding negTokenInit header\n");
		return 0;
	} else if ((cls != ASN1_APL) || (con != ASN1_CON)
		   || (tag != ASN1_EOC)) {
		cifs_dbg(FYI, "cls = %d con = %d tag = %d\n", 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) {
		cifs_dbg(FYI, "Error decoding negTokenInit header\n");
		return 0;
	}

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

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

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

	/* sequence of */
	if (asn1_header_decode
	    (&ctx, &sequence_end, &cls, &con, &tag) == 0) {
		cifs_dbg(FYI, "Error decoding 2nd part of negTokenInit\n");
		return 0;
	} else if ((cls != ASN1_UNI) || (con != ASN1_CON)
		   || (tag != ASN1_SEQ)) {
		cifs_dbg(FYI, "cls = %d con = %d tag = %d end = %p (%d) exit 1\n",
			 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) {
			cifs_dbg(FYI, "Error decoding negTokenInit hdr exit2\n");
			return 0;
		}
		if ((tag == ASN1_OJI) && (con == ASN1_PRI)) {
			if (asn1_oid_decode(&ctx, end, &oid, &oidlen)) {

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

				if (compare_oid(oid, oidlen, MSKRB5_OID,
						MSKRB5_OID_LEN))
					server->sec_mskerberos = true;
				else if (compare_oid(oid, oidlen, KRB5U2U_OID,
						     KRB5U2U_OID_LEN))
					server->sec_kerberosu2u = true;
				else if (compare_oid(oid, oidlen, KRB5_OID,
						     KRB5_OID_LEN))
					server->sec_kerberos = true;
				else if (compare_oid(oid, oidlen, NTLMSSP_OID,
						     NTLMSSP_OID_LEN))
					server->sec_ntlmssp = true;

				kfree(oid);
			}
		} else {
			cifs_dbg(FYI, "Should be an oid what is going on?\n");
		}
	}

	/*
	 * We currently ignore anything at the end of the SPNEGO blob after
	 * the mechTypes have been parsed, since none of that info is
	 * used at the moment.
	 */
	return 1;
}
Commit	Line	Data
1a59d1b8	1	// SPDX-License-Identifier: GPL-2.0-or-later
50c2f753	2	/*
1da177e4 LT	3	* The ASB.1/BER parsing code is derived from ip_nat_snmp_basic.c which was in
1da177e4 LT	4	* turn derived from the gxsnmp package by Gregory McLean & Jochen Friedrich
50c2f753	5	*
1da177e4	6	* Copyright (c) 2000 RP Internet (www.rpi.net.au).
1da177e4 LT	7	*/
1da177e4 LT	8
1da177e4 LT	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 "cifspdu.h"
	15	#include "cifsglob.h"
	16	#include "cifs_debug.h"
	17	#include "cifsproto.h"
	18
	19	/*****************************************************************************
	20	*
	21	* Basic ASN.1 decoding routines (gxsnmp author Dirk Wisse)
	22	*
	23	*****************************************************************************/
	24
	25	/* Class */
	26	#define ASN1_UNI 0 /* Universal */
	27	#define ASN1_APL 1 /* Application */
	28	#define ASN1_CTX 2 /* Context */
	29	#define ASN1_PRV 3 /* Private */
	30
	31	/* Tag */
	32	#define ASN1_EOC 0 /* End Of Contents or N/A */
	33	#define ASN1_BOL 1 /* Boolean */
	34	#define ASN1_INT 2 /* Integer */
	35	#define ASN1_BTS 3 /* Bit String */
	36	#define ASN1_OTS 4 /* Octet String */
	37	#define ASN1_NUL 5 /* Null */
	38	#define ASN1_OJI 6 /* Object Identifier */
	39	#define ASN1_OJD 7 /* Object Description */
	40	#define ASN1_EXT 8 /* External */
f46c7234	41	#define ASN1_ENUM 10 /* Enumerated */
1da177e4 LT	42	#define ASN1_SEQ 16 /* Sequence */
	43	#define ASN1_SET 17 /* Set */
	44	#define ASN1_NUMSTR 18 /* Numerical String */
	45	#define ASN1_PRNSTR 19 /* Printable String */
	46	#define ASN1_TEXSTR 20 /* Teletext String */
	47	#define ASN1_VIDSTR 21 /* Video String */
	48	#define ASN1_IA5STR 22 /* IA5 String */
	49	#define ASN1_UNITIM 23 /* Universal Time */
	50	#define ASN1_GENTIM 24 /* General Time */
	51	#define ASN1_GRASTR 25 /* Graphical String */
	52	#define ASN1_VISSTR 26 /* Visible String */
	53	#define ASN1_GENSTR 27 /* General String */
	54
	55	/* Primitive / Constructed methods*/
	56	#define ASN1_PRI 0 /* Primitive */
	57	#define ASN1_CON 1 /* Constructed */
	58
	59	/*
	60	* Error codes.
	61	*/
	62	#define ASN1_ERR_NOERROR 0
	63	#define ASN1_ERR_DEC_EMPTY 2
	64	#define ASN1_ERR_DEC_EOC_MISMATCH 3
	65	#define ASN1_ERR_DEC_LENGTH_MISMATCH 4
	66	#define ASN1_ERR_DEC_BADVALUE 5
	67
	68	#define SPNEGO_OID_LEN 7
	69	#define NTLMSSP_OID_LEN 10
e545937a	70	#define KRB5_OID_LEN 7
f46c7234	71	#define KRB5U2U_OID_LEN 8
e545937a	72	#define MSKRB5_OID_LEN 7
1da177e4 LT	73	static unsigned long SPNEGO_OID[7] = { 1, 3, 6, 1, 5, 5, 2 };
1da177e4 LT	74	static unsigned long NTLMSSP_OID[10] = { 1, 3, 6, 1, 4, 1, 311, 2, 2, 10 };
e545937a	75	static unsigned long KRB5_OID[7] = { 1, 2, 840, 113554, 1, 2, 2 };
f46c7234	76	static unsigned long KRB5U2U_OID[8] = { 1, 2, 840, 113554, 1, 2, 2, 3 };
e545937a	77	static unsigned long MSKRB5_OID[7] = { 1, 2, 840, 48018, 1, 2, 2 };
1da177e4	78
50c2f753	79	/*
1da177e4 LT	80	* ASN.1 context.
	81	*/
	82	struct asn1_ctx {
	83	int error; /* Error condition */
	84	unsigned char pointer; / Octet just to be decoded */
	85	unsigned char begin; / First octet */
	86	unsigned char end; / Octet after last octet */
	87	};
	88
	89	/*
	90	* Octet string (not null terminated)
	91	*/
	92	struct asn1_octstr {
	93	unsigned char *data;
	94	unsigned int len;
	95	};
	96
	97	static void
	98	asn1_open(struct asn1_ctx ctx, unsigned char buf, unsigned int len)
	99	{
	100	ctx->begin = buf;
	101	ctx->end = buf + len;
	102	ctx->pointer = buf;
	103	ctx->error = ASN1_ERR_NOERROR;
	104	}
	105
	106	static unsigned char
	107	asn1_octet_decode(struct asn1_ctx ctx, unsigned char ch)
	108	{
	109	if (ctx->pointer >= ctx->end) {
	110	ctx->error = ASN1_ERR_DEC_EMPTY;
	111	return 0;
	112	}
	113	ch = (ctx->pointer)++;
	114	return 1;
	115	}
	116
f46c7234 SF	117	#if 0 /* will be needed later by spnego decoding/encoding of ntlmssp */
	118	static unsigned char
	119	asn1_enum_decode(struct asn1_ctx ctx, __le32 val)
	120	{
	121	unsigned char ch;
	122
	123	if (ctx->pointer >= ctx->end) {
	124	ctx->error = ASN1_ERR_DEC_EMPTY;
	125	return 0;
	126	}
	127
1537a363	128	ch = (ctx->pointer)++; / ch has 0xa, ptr points to length octet */
f46c7234 SF	129	if ((ch) == ASN1_ENUM) /* if ch value is ENUM, 0xa */
	130	val = (++(ctx->pointer)); /* value has enum value */
	131	else
	132	return 0;
	133
	134	ctx->pointer++;
	135	return 1;
	136	}
	137	#endif
	138
1da177e4 LT	139	static unsigned char
	140	asn1_tag_decode(struct asn1_ctx ctx, unsigned int tag)
	141	{
	142	unsigned char ch;
	143
	144	*tag = 0;
	145
	146	do {
	147	if (!asn1_octet_decode(ctx, &ch))
	148	return 0;
	149	*tag <<= 7;
	150	*tag \|= ch & 0x7F;
	151	} while ((ch & 0x80) == 0x80);
	152	return 1;
	153	}
	154
	155	static unsigned char
	156	asn1_id_decode(struct asn1_ctx *ctx,
	157	unsigned int cls, unsigned int con, unsigned int *tag)
	158	{
	159	unsigned char ch;
	160
	161	if (!asn1_octet_decode(ctx, &ch))
	162	return 0;
	163
	164	*cls = (ch & 0xC0) >> 6;
	165	*con = (ch & 0x20) >> 5;
	166	*tag = (ch & 0x1F);
	167
	168	if (*tag == 0x1F) {
	169	if (!asn1_tag_decode(ctx, tag))
	170	return 0;
	171	}
	172	return 1;
	173	}
	174
	175	static unsigned char
	176	asn1_length_decode(struct asn1_ctx ctx, unsigned int def, unsigned int *len)
	177	{
	178	unsigned char ch, cnt;
	179
	180	if (!asn1_octet_decode(ctx, &ch))
	181	return 0;
	182
	183	if (ch == 0x80)
	184	*def = 0;
	185	else {
	186	*def = 1;
	187
	188	if (ch < 0x80)
	189	*len = ch;
	190	else {
	191	cnt = (unsigned char) (ch & 0x7F);
	192	*len = 0;
	193
	194	while (cnt > 0) {
	195	if (!asn1_octet_decode(ctx, &ch))
	196	return 0;
	197	*len <<= 8;
	198	*len \|= ch;
	199	cnt--;
	200	}
	201	}
	202	}
ddb2c435 CW	203
	204	/* don't trust len bigger than ctx buffer */
	205	if (*len > ctx->end - ctx->pointer)
	206	return 0;
	207
1da177e4 LT	208	return 1;
	209	}
	210
	211	static unsigned char
	212	asn1_header_decode(struct asn1_ctx *ctx,
	213	unsigned char **eoc,
	214	unsigned int cls, unsigned int con, unsigned int *tag)
	215	{
50c2f753	216	unsigned int def = 0;
ab2f218f	217	unsigned int len = 0;
1da177e4 LT	218
	219	if (!asn1_id_decode(ctx, cls, con, tag))
	220	return 0;
	221
	222	if (!asn1_length_decode(ctx, &def, &len))
	223	return 0;
	224
ddb2c435 CW	225	/* primitive shall be definite, indefinite shall be constructed */
	226	if (*con == ASN1_PRI && !def)
	227	return 0;
	228
1da177e4 LT	229	if (def)
	230	*eoc = ctx->pointer + len;
	231	else
	232	*eoc = NULL;
	233	return 1;
	234	}
	235
	236	static unsigned char
	237	asn1_eoc_decode(struct asn1_ctx ctx, unsigned char eoc)
	238	{
	239	unsigned char ch;
	240
	241	if (eoc == NULL) {
	242	if (!asn1_octet_decode(ctx, &ch))
	243	return 0;
	244
	245	if (ch != 0x00) {
	246	ctx->error = ASN1_ERR_DEC_EOC_MISMATCH;
	247	return 0;
	248	}
	249
	250	if (!asn1_octet_decode(ctx, &ch))
	251	return 0;
	252
	253	if (ch != 0x00) {
	254	ctx->error = ASN1_ERR_DEC_EOC_MISMATCH;
	255	return 0;
	256	}
	257	return 1;
	258	} else {
	259	if (ctx->pointer != eoc) {
	260	ctx->error = ASN1_ERR_DEC_LENGTH_MISMATCH;
	261	return 0;
	262	}
	263	return 1;
	264	}
	265	}
	266
	267	/* static unsigned char asn1_null_decode(struct asn1_ctx *ctx,
	268	unsigned char *eoc)
	269	{
	270	ctx->pointer = eoc;
	271	return 1;
	272	}
	273
	274	static unsigned char asn1_long_decode(struct asn1_ctx *ctx,
	275	unsigned char eoc, long integer)
	276	{
	277	unsigned char ch;
	278	unsigned int len;
	279
	280	if (!asn1_octet_decode(ctx, &ch))
	281	return 0;
	282
	283	*integer = (signed char) ch;
	284	len = 1;
	285
	286	while (ctx->pointer < eoc) {
	287	if (++len > sizeof(long)) {
	288	ctx->error = ASN1_ERR_DEC_BADVALUE;
	289	return 0;
	290	}
	291
	292	if (!asn1_octet_decode(ctx, &ch))
293	return 0;
294
295	*integer <<= 8;
296	*integer \|= ch;
297	}
298	return 1;
299	}
300
301	static unsigned char asn1_uint_decode(struct asn1_ctx *ctx,
302	unsigned char *eoc,
303	unsigned int *integer)
304	{
305	unsigned char ch;
306	unsigned int len;
307
308	if (!asn1_octet_decode(ctx, &ch))
309	return 0;
310
311	*integer = ch;
312	if (ch == 0)
313	len = 0;
314	else
315	len = 1;
316
317	while (ctx->pointer < eoc) {
318	if (++len > sizeof(unsigned int)) {
319	ctx->error = ASN1_ERR_DEC_BADVALUE;
320	return 0;
321	}
322
323	if (!asn1_octet_decode(ctx, &ch))
324	return 0;
325
326	*integer <<= 8;
327	*integer \|= ch;
328	}
329	return 1;
330	}
331
332	static unsigned char asn1_ulong_decode(struct asn1_ctx *ctx,
333	unsigned char *eoc,
334	unsigned long *integer)
335	{
336	unsigned char ch;
337	unsigned int len;
338
339	if (!asn1_octet_decode(ctx, &ch))
340	return 0;
341
342	*integer = ch;
343	if (ch == 0)
344	len = 0;
345	else
346	len = 1;
347
348	while (ctx->pointer < eoc) {
349	if (++len > sizeof(unsigned long)) {
350	ctx->error = ASN1_ERR_DEC_BADVALUE;
351	return 0;
352	}
353
354	if (!asn1_octet_decode(ctx, &ch))
355	return 0;
356
357	*integer <<= 8;
358	*integer \|= ch;
359	}
360	return 1;
50c2f753	361	}
1da177e4 LT	362
	363	static unsigned char
	364	asn1_octets_decode(struct asn1_ctx *ctx,
	365	unsigned char *eoc,
	366	unsigned char *octets, unsigned int len)
	367	{
	368	unsigned char *ptr;
	369
	370	*len = 0;
	371
	372	*octets = kmalloc(eoc - ctx->pointer, GFP_ATOMIC);
	373	if (*octets == NULL) {
	374	return 0;
	375	}
	376
	377	ptr = *octets;
	378	while (ctx->pointer < eoc) {
	379	if (!asn1_octet_decode(ctx, (unsigned char *) ptr++)) {
	380	kfree(*octets);
	381	*octets = NULL;
	382	return 0;
	383	}
	384	(*len)++;
	385	}
	386	return 1;
	387	} */
	388
	389	static unsigned char
	390	asn1_subid_decode(struct asn1_ctx ctx, unsigned long subid)
	391	{
	392	unsigned char ch;
	393
	394	*subid = 0;
	395
	396	do {
	397	if (!asn1_octet_decode(ctx, &ch))
	398	return 0;
	399
	400	*subid <<= 7;
	401	*subid \|= ch & 0x7F;
	402	} while ((ch & 0x80) == 0x80);
	403	return 1;
	404	}
	405
50c2f753	406	static int
1da177e4 LT	407	asn1_oid_decode(struct asn1_ctx *ctx,
	408	unsigned char eoc, unsigned long oid, unsigned int len)
	409	{
	410	unsigned long subid;
	411	unsigned int size;
	412	unsigned long *optr;
	413
	414	size = eoc - ctx->pointer + 1;
ddb2c435 CW	415
ddb2c435 CW	416	/* first subid actually encodes first two subids */
04e1e0cc	417	if (size < 2 \|\| size > UINT_MAX/sizeof(unsigned long))
ddb2c435 CW	418	return 0;
ddb2c435 CW	419
6da2ec56	420	*oid = kmalloc_array(size, sizeof(unsigned long), GFP_ATOMIC);
26f57364	421	if (*oid == NULL)
1da177e4	422	return 0;
1da177e4 LT	423
	424	optr = *oid;
	425
	426	if (!asn1_subid_decode(ctx, &subid)) {
	427	kfree(*oid);
	428	*oid = NULL;
	429	return 0;
	430	}
	431
	432	if (subid < 40) {
	433	optr[0] = 0;
	434	optr[1] = subid;
	435	} else if (subid < 80) {
	436	optr[0] = 1;
	437	optr[1] = subid - 40;
	438	} else {
	439	optr[0] = 2;
	440	optr[1] = subid - 80;
	441	}
	442
	443	*len = 2;
	444	optr += 2;
	445
	446	while (ctx->pointer < eoc) {
	447	if (++(*len) > size) {
	448	ctx->error = ASN1_ERR_DEC_BADVALUE;
	449	kfree(*oid);
	450	*oid = NULL;
	451	return 0;
	452	}
	453
	454	if (!asn1_subid_decode(ctx, optr++)) {
	455	kfree(*oid);
	456	*oid = NULL;
	457	return 0;
	458	}
	459	}
	460	return 1;
	461	}
	462
	463	static int
	464	compare_oid(unsigned long *oid1, unsigned int oid1len,
	465	unsigned long *oid2, unsigned int oid2len)
	466	{
	467	unsigned int i;
	468
	469	if (oid1len != oid2len)
	470	return 0;
	471	else {
	472	for (i = 0; i < oid1len; i++) {
	473	if (oid1[i] != oid2[i])
	474	return 0;
	475	}
	476	return 1;
	477	}
	478	}
	479
	480	/* BB check for endian conversion issues here */
	481
	482	int
	483	decode_negTokenInit(unsigned char *security_blob, int length,
26efa0ba	484	struct TCP_Server_Info *server)
1da177e4 LT	485	{
	486	struct asn1_ctx ctx;
	487	unsigned char *end;
	488	unsigned char *sequence_end;
	489	unsigned long *oid = NULL;
	490	unsigned int cls, con, tag, oidlen, rc;
1da177e4	491
1da177e4 LT	492	/* cifs_dump_mem(" Received SecBlob ", security_blob, length); */
	493
	494	asn1_open(&ctx, security_blob, length);
	495
2f0e58ac	496	/* GSSAPI header */
1da177e4	497	if (asn1_header_decode(&ctx, &end, &cls, &con, &tag) == 0) {
f96637be	498	cifs_dbg(FYI, "Error decoding negTokenInit header\n");
1da177e4 LT	499	return 0;
	500	} else if ((cls != ASN1_APL) \|\| (con != ASN1_CON)
	501	\|\| (tag != ASN1_EOC)) {
f96637be	502	cifs_dbg(FYI, "cls = %d con = %d tag = %d\n", cls, con, tag);
1da177e4	503	return 0;
2f0e58ac	504	}
1da177e4	505
2f0e58ac JL	506	/* Check for SPNEGO OID -- remember to free obj->oid */
	507	rc = asn1_header_decode(&ctx, &end, &cls, &con, &tag);
	508	if (rc) {
	509	if ((tag == ASN1_OJI) && (con == ASN1_PRI) &&
	510	(cls == ASN1_UNI)) {
	511	rc = asn1_oid_decode(&ctx, end, &oid, &oidlen);
	512	if (rc) {
	513	rc = compare_oid(oid, oidlen, SPNEGO_OID,
	514	SPNEGO_OID_LEN);
	515	kfree(oid);
	516	}
	517	} else
	518	rc = 0;
	519	}
1da177e4	520
2f0e58ac JL	521	/* SPNEGO OID not present or garbled -- bail out */
2f0e58ac JL	522	if (!rc) {
f96637be	523	cifs_dbg(FYI, "Error decoding negTokenInit header\n");
2f0e58ac JL	524	return 0;
2f0e58ac JL	525	}
1da177e4	526
f46c7234	527	/* SPNEGO */
2f0e58ac	528	if (asn1_header_decode(&ctx, &end, &cls, &con, &tag) == 0) {
f96637be	529	cifs_dbg(FYI, "Error decoding negTokenInit\n");
2f0e58ac JL	530	return 0;
	531	} else if ((cls != ASN1_CTX) \|\| (con != ASN1_CON)
	532	\|\| (tag != ASN1_EOC)) {
f96637be JP	533	cifs_dbg(FYI, "cls = %d con = %d tag = %d end = %p (%d) exit 0\n",
f96637be JP	534	cls, con, tag, end, *end);
2f0e58ac JL	535	return 0;
2f0e58ac JL	536	}
1da177e4	537
f46c7234	538	/* negTokenInit */
2f0e58ac	539	if (asn1_header_decode(&ctx, &end, &cls, &con, &tag) == 0) {
f96637be	540	cifs_dbg(FYI, "Error decoding negTokenInit\n");
2f0e58ac JL	541	return 0;
	542	} else if ((cls != ASN1_UNI) \|\| (con != ASN1_CON)
	543	\|\| (tag != ASN1_SEQ)) {
f96637be JP	544	cifs_dbg(FYI, "cls = %d con = %d tag = %d end = %p (%d) exit 1\n",
f96637be JP	545	cls, con, tag, end, *end);
2f0e58ac JL	546	return 0;
2f0e58ac JL	547	}
1da177e4	548
f46c7234	549	/* sequence */
2f0e58ac	550	if (asn1_header_decode(&ctx, &end, &cls, &con, &tag) == 0) {
f96637be	551	cifs_dbg(FYI, "Error decoding 2nd part of negTokenInit\n");
2f0e58ac JL	552	return 0;
	553	} else if ((cls != ASN1_CTX) \|\| (con != ASN1_CON)
	554	\|\| (tag != ASN1_EOC)) {
f96637be JP	555	cifs_dbg(FYI, "cls = %d con = %d tag = %d end = %p (%d) exit 0\n",
f96637be JP	556	cls, con, tag, end, *end);
2f0e58ac JL	557	return 0;
2f0e58ac JL	558	}
1da177e4	559
f46c7234	560	/* sequence of */
2f0e58ac JL	561	if (asn1_header_decode
2f0e58ac JL	562	(&ctx, &sequence_end, &cls, &con, &tag) == 0) {
f96637be	563	cifs_dbg(FYI, "Error decoding 2nd part of negTokenInit\n");
2f0e58ac JL	564	return 0;
	565	} else if ((cls != ASN1_UNI) \|\| (con != ASN1_CON)
	566	\|\| (tag != ASN1_SEQ)) {
f96637be JP	567	cifs_dbg(FYI, "cls = %d con = %d tag = %d end = %p (%d) exit 1\n",
f96637be JP	568	cls, con, tag, end, *end);
2f0e58ac JL	569	return 0;
2f0e58ac JL	570	}
1da177e4	571
f46c7234	572	/* list of security mechanisms */
2f0e58ac JL	573	while (!asn1_eoc_decode(&ctx, sequence_end)) {
	574	rc = asn1_header_decode(&ctx, &end, &cls, &con, &tag);
	575	if (!rc) {
f96637be	576	cifs_dbg(FYI, "Error decoding negTokenInit hdr exit2\n");
1da177e4 LT	577	return 0;
1da177e4 LT	578	}
2f0e58ac JL	579	if ((tag == ASN1_OJI) && (con == ASN1_PRI)) {
	580	if (asn1_oid_decode(&ctx, end, &oid, &oidlen)) {
	581
f96637be JP	582	cifs_dbg(FYI, "OID len = %d oid = 0x%lx 0x%lx 0x%lx 0x%lx\n",
	583	oidlen, oid, (oid + 1), *(oid + 2),
	584	*(oid + 3));
2f0e58ac JL	585
2f0e58ac JL	586	if (compare_oid(oid, oidlen, MSKRB5_OID,
26efa0ba JL	587	MSKRB5_OID_LEN))
26efa0ba JL	588	server->sec_mskerberos = true;
c8e56f1f	589	else if (compare_oid(oid, oidlen, KRB5U2U_OID,
26efa0ba JL	590	KRB5U2U_OID_LEN))
26efa0ba JL	591	server->sec_kerberosu2u = true;
c8e56f1f	592	else if (compare_oid(oid, oidlen, KRB5_OID,
26efa0ba JL	593	KRB5_OID_LEN))
26efa0ba JL	594	server->sec_kerberos = true;
c8e56f1f	595	else if (compare_oid(oid, oidlen, NTLMSSP_OID,
2f0e58ac	596	NTLMSSP_OID_LEN))
26efa0ba	597	server->sec_ntlmssp = true;
2f0e58ac JL	598
	599	kfree(oid);
	600	}
	601	} else {
f96637be	602	cifs_dbg(FYI, "Should be an oid what is going on?\n");
1da177e4	603	}
2f0e58ac	604	}
1da177e4	605
f853c616 JL	606	/*
	607	* We currently ignore anything at the end of the SPNEGO blob after
	608	* the mechTypes have been parsed, since none of that info is
	609	* used at the moment.
	610	*/
1da177e4 LT	611	return 1;
1da177e4 LT	612	}