Release 4.10 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;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
steve french
steve french
46
100.00%
1
100.00%
Total
46
100.00%
1
100.00%


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;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
steve french
steve french
52
100.00%
1
100.00%
Total
52
100.00%
1
100.00%

#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;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
steve french
steve french
69
100.00%
1
100.00%
Total
69
100.00%
1
100.00%


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;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
steve french
steve french
101
100.00%
1
100.00%
Total
101
100.00%
1
100.00%


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;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
steve french
steve french
130
88.44%
1
50.00%
chris wright
chris wright
17
11.56%
1
50.00%
Total
147
100.00%
2
100.00%


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;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
steve french
steve french
101
87.83%
3
75.00%
chris wright
chris wright
14
12.17%
1
25.00%
Total
115
100.00%
4
100.00%


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;
	}
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
steve french
steve french
119
100.00%
2
100.00%
Total
119
100.00%
2
100.00%

/* 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;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
steve french
steve french
69
100.00%
1
100.00%
Total
69
100.00%
1
100.00%


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;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
steve french
steve french
255
92.73%
2
50.00%
chris wright
chris wright
19
6.91%
1
25.00%
jan beulich
jan beulich
1
0.36%
1
25.00%
Total
275
100.00%
4
100.00%


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;
	}
}

	
Contributors
Person
Tokens
Prop
Commits
CommitProp
steve french
steve french
73
100.00%
2
100.00%
Total
73
100.00%
2
100.00%

/* 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;
}
Contributors
Person
Tokens
Prop
Commits
CommitProp
steve french
steve french
657
84.23%
8
53.33%
joe perches
joe perches
70
8.97%
2
13.33%
jeff layton
jeff layton
52
6.67%
4
26.67%
chris wright
chris wright
1
0.13%
1
6.67%
Total
780
100.00%
15
100.00%

Overall Contributors
Person
Tokens
Prop
Commits
CommitProp
steve french
steve french
2014
89.71%
14
58.33%
jeff layton
jeff layton
108
4.81%
4
16.67%
joe perches
joe perches
70
3.12%
2
8.33%
chris wright
chris wright
51
2.27%
2
8.33%
jan beulich
jan beulich
1
0.04%
1
4.17%
daniel mack
daniel mack
1
0.04%
1
4.17%
Total
2245
100.00%
24
100.00%
Directory: fs/cifs

Information contained on this website is for historical information purposes only and does not indicate or represent copyright ownership.