624 lines
14 KiB
C
624 lines
14 KiB
C
/*
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* The ASB.1/BER parsing code is derived from ip_nat_snmp_basic.c which was in
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* turn derived from the gxsnmp package by Gregory McLean & Jochen Friedrich
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*
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* Copyright (c) 2000 RP Internet (www.rpi.net.au).
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#include <linux/module.h>
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#include <linux/types.h>
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#include <linux/kernel.h>
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#include <linux/mm.h>
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#include <linux/slab.h>
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#include "cifspdu.h"
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#include "cifsglob.h"
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#include "cifs_debug.h"
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#include "cifsproto.h"
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/*****************************************************************************
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*
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* Basic ASN.1 decoding routines (gxsnmp author Dirk Wisse)
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*
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*****************************************************************************/
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/* Class */
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#define ASN1_UNI 0 /* Universal */
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#define ASN1_APL 1 /* Application */
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#define ASN1_CTX 2 /* Context */
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#define ASN1_PRV 3 /* Private */
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/* Tag */
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#define ASN1_EOC 0 /* End Of Contents or N/A */
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#define ASN1_BOL 1 /* Boolean */
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#define ASN1_INT 2 /* Integer */
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#define ASN1_BTS 3 /* Bit String */
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#define ASN1_OTS 4 /* Octet String */
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#define ASN1_NUL 5 /* Null */
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#define ASN1_OJI 6 /* Object Identifier */
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#define ASN1_OJD 7 /* Object Description */
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#define ASN1_EXT 8 /* External */
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#define ASN1_ENUM 10 /* Enumerated */
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#define ASN1_SEQ 16 /* Sequence */
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#define ASN1_SET 17 /* Set */
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#define ASN1_NUMSTR 18 /* Numerical String */
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#define ASN1_PRNSTR 19 /* Printable String */
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#define ASN1_TEXSTR 20 /* Teletext String */
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#define ASN1_VIDSTR 21 /* Video String */
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#define ASN1_IA5STR 22 /* IA5 String */
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#define ASN1_UNITIM 23 /* Universal Time */
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#define ASN1_GENTIM 24 /* General Time */
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#define ASN1_GRASTR 25 /* Graphical String */
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#define ASN1_VISSTR 26 /* Visible String */
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#define ASN1_GENSTR 27 /* General String */
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/* Primitive / Constructed methods*/
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#define ASN1_PRI 0 /* Primitive */
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#define ASN1_CON 1 /* Constructed */
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/*
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* Error codes.
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*/
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#define ASN1_ERR_NOERROR 0
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#define ASN1_ERR_DEC_EMPTY 2
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#define ASN1_ERR_DEC_EOC_MISMATCH 3
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#define ASN1_ERR_DEC_LENGTH_MISMATCH 4
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#define ASN1_ERR_DEC_BADVALUE 5
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#define SPNEGO_OID_LEN 7
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#define NTLMSSP_OID_LEN 10
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#define KRB5_OID_LEN 7
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#define KRB5U2U_OID_LEN 8
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#define MSKRB5_OID_LEN 7
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static unsigned long SPNEGO_OID[7] = { 1, 3, 6, 1, 5, 5, 2 };
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static unsigned long NTLMSSP_OID[10] = { 1, 3, 6, 1, 4, 1, 311, 2, 2, 10 };
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static unsigned long KRB5_OID[7] = { 1, 2, 840, 113554, 1, 2, 2 };
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static unsigned long KRB5U2U_OID[8] = { 1, 2, 840, 113554, 1, 2, 2, 3 };
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static unsigned long MSKRB5_OID[7] = { 1, 2, 840, 48018, 1, 2, 2 };
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/*
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* ASN.1 context.
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*/
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struct asn1_ctx {
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int error; /* Error condition */
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unsigned char *pointer; /* Octet just to be decoded */
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unsigned char *begin; /* First octet */
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unsigned char *end; /* Octet after last octet */
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};
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/*
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* Octet string (not null terminated)
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*/
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struct asn1_octstr {
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unsigned char *data;
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unsigned int len;
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};
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static void
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asn1_open(struct asn1_ctx *ctx, unsigned char *buf, unsigned int len)
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{
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ctx->begin = buf;
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ctx->end = buf + len;
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ctx->pointer = buf;
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ctx->error = ASN1_ERR_NOERROR;
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}
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static unsigned char
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asn1_octet_decode(struct asn1_ctx *ctx, unsigned char *ch)
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{
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if (ctx->pointer >= ctx->end) {
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ctx->error = ASN1_ERR_DEC_EMPTY;
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return 0;
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}
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*ch = *(ctx->pointer)++;
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return 1;
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}
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#if 0 /* will be needed later by spnego decoding/encoding of ntlmssp */
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static unsigned char
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asn1_enum_decode(struct asn1_ctx *ctx, __le32 *val)
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{
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unsigned char ch;
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if (ctx->pointer >= ctx->end) {
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ctx->error = ASN1_ERR_DEC_EMPTY;
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return 0;
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}
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ch = *(ctx->pointer)++; /* ch has 0xa, ptr points to length octet */
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if ((ch) == ASN1_ENUM) /* if ch value is ENUM, 0xa */
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*val = *(++(ctx->pointer)); /* value has enum value */
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else
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return 0;
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ctx->pointer++;
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return 1;
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}
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#endif
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static unsigned char
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asn1_tag_decode(struct asn1_ctx *ctx, unsigned int *tag)
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{
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unsigned char ch;
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*tag = 0;
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do {
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if (!asn1_octet_decode(ctx, &ch))
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return 0;
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*tag <<= 7;
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*tag |= ch & 0x7F;
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} while ((ch & 0x80) == 0x80);
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return 1;
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}
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static unsigned char
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asn1_id_decode(struct asn1_ctx *ctx,
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unsigned int *cls, unsigned int *con, unsigned int *tag)
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{
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unsigned char ch;
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if (!asn1_octet_decode(ctx, &ch))
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return 0;
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*cls = (ch & 0xC0) >> 6;
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*con = (ch & 0x20) >> 5;
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*tag = (ch & 0x1F);
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if (*tag == 0x1F) {
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if (!asn1_tag_decode(ctx, tag))
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return 0;
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}
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return 1;
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}
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static unsigned char
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asn1_length_decode(struct asn1_ctx *ctx, unsigned int *def, unsigned int *len)
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{
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unsigned char ch, cnt;
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if (!asn1_octet_decode(ctx, &ch))
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return 0;
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if (ch == 0x80)
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*def = 0;
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else {
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*def = 1;
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if (ch < 0x80)
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*len = ch;
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else {
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cnt = (unsigned char) (ch & 0x7F);
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*len = 0;
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while (cnt > 0) {
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if (!asn1_octet_decode(ctx, &ch))
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return 0;
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*len <<= 8;
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*len |= ch;
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cnt--;
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}
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}
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}
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/* don't trust len bigger than ctx buffer */
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if (*len > ctx->end - ctx->pointer)
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return 0;
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return 1;
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}
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static unsigned char
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asn1_header_decode(struct asn1_ctx *ctx,
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unsigned char **eoc,
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unsigned int *cls, unsigned int *con, unsigned int *tag)
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{
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unsigned int def = 0;
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unsigned int len = 0;
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if (!asn1_id_decode(ctx, cls, con, tag))
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return 0;
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if (!asn1_length_decode(ctx, &def, &len))
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return 0;
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/* primitive shall be definite, indefinite shall be constructed */
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if (*con == ASN1_PRI && !def)
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return 0;
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if (def)
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*eoc = ctx->pointer + len;
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else
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*eoc = NULL;
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return 1;
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}
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static unsigned char
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asn1_eoc_decode(struct asn1_ctx *ctx, unsigned char *eoc)
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{
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unsigned char ch;
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if (eoc == NULL) {
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if (!asn1_octet_decode(ctx, &ch))
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return 0;
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if (ch != 0x00) {
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ctx->error = ASN1_ERR_DEC_EOC_MISMATCH;
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return 0;
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}
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if (!asn1_octet_decode(ctx, &ch))
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return 0;
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if (ch != 0x00) {
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ctx->error = ASN1_ERR_DEC_EOC_MISMATCH;
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return 0;
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}
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return 1;
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} else {
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if (ctx->pointer != eoc) {
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ctx->error = ASN1_ERR_DEC_LENGTH_MISMATCH;
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return 0;
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}
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return 1;
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}
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}
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/* static unsigned char asn1_null_decode(struct asn1_ctx *ctx,
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unsigned char *eoc)
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{
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ctx->pointer = eoc;
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return 1;
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}
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static unsigned char asn1_long_decode(struct asn1_ctx *ctx,
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unsigned char *eoc, long *integer)
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{
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unsigned char ch;
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unsigned int len;
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if (!asn1_octet_decode(ctx, &ch))
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return 0;
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*integer = (signed char) ch;
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len = 1;
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while (ctx->pointer < eoc) {
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if (++len > sizeof(long)) {
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ctx->error = ASN1_ERR_DEC_BADVALUE;
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return 0;
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}
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if (!asn1_octet_decode(ctx, &ch))
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return 0;
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*integer <<= 8;
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*integer |= ch;
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}
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return 1;
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}
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static unsigned char asn1_uint_decode(struct asn1_ctx *ctx,
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unsigned char *eoc,
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unsigned int *integer)
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{
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unsigned char ch;
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unsigned int len;
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if (!asn1_octet_decode(ctx, &ch))
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return 0;
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*integer = ch;
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if (ch == 0)
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len = 0;
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else
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len = 1;
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while (ctx->pointer < eoc) {
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if (++len > sizeof(unsigned int)) {
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ctx->error = ASN1_ERR_DEC_BADVALUE;
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return 0;
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}
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if (!asn1_octet_decode(ctx, &ch))
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return 0;
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*integer <<= 8;
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*integer |= ch;
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}
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return 1;
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}
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static unsigned char asn1_ulong_decode(struct asn1_ctx *ctx,
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unsigned char *eoc,
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unsigned long *integer)
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{
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unsigned char ch;
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unsigned int len;
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if (!asn1_octet_decode(ctx, &ch))
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return 0;
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*integer = ch;
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if (ch == 0)
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len = 0;
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else
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len = 1;
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while (ctx->pointer < eoc) {
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if (++len > sizeof(unsigned long)) {
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ctx->error = ASN1_ERR_DEC_BADVALUE;
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return 0;
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}
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if (!asn1_octet_decode(ctx, &ch))
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return 0;
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*integer <<= 8;
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*integer |= ch;
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}
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return 1;
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}
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static unsigned char
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asn1_octets_decode(struct asn1_ctx *ctx,
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unsigned char *eoc,
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unsigned char **octets, unsigned int *len)
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{
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unsigned char *ptr;
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*len = 0;
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*octets = kmalloc(eoc - ctx->pointer, GFP_ATOMIC);
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if (*octets == NULL) {
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return 0;
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}
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ptr = *octets;
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while (ctx->pointer < eoc) {
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if (!asn1_octet_decode(ctx, (unsigned char *) ptr++)) {
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kfree(*octets);
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*octets = NULL;
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return 0;
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}
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(*len)++;
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}
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return 1;
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} */
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static unsigned char
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asn1_subid_decode(struct asn1_ctx *ctx, unsigned long *subid)
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{
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unsigned char ch;
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*subid = 0;
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do {
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if (!asn1_octet_decode(ctx, &ch))
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return 0;
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*subid <<= 7;
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*subid |= ch & 0x7F;
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} while ((ch & 0x80) == 0x80);
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return 1;
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}
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static int
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asn1_oid_decode(struct asn1_ctx *ctx,
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unsigned char *eoc, unsigned long **oid, unsigned int *len)
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{
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unsigned long subid;
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unsigned int size;
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unsigned long *optr;
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size = eoc - ctx->pointer + 1;
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/* first subid actually encodes first two subids */
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if (size < 2 || size > UINT_MAX/sizeof(unsigned long))
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return 0;
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*oid = kmalloc_array(size, sizeof(unsigned long), GFP_ATOMIC);
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if (*oid == NULL)
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return 0;
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optr = *oid;
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if (!asn1_subid_decode(ctx, &subid)) {
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kfree(*oid);
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*oid = NULL;
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return 0;
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}
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if (subid < 40) {
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optr[0] = 0;
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optr[1] = subid;
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} else if (subid < 80) {
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optr[0] = 1;
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optr[1] = subid - 40;
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} else {
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optr[0] = 2;
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optr[1] = subid - 80;
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}
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*len = 2;
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optr += 2;
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while (ctx->pointer < eoc) {
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if (++(*len) > size) {
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ctx->error = ASN1_ERR_DEC_BADVALUE;
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kfree(*oid);
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*oid = NULL;
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return 0;
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}
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if (!asn1_subid_decode(ctx, optr++)) {
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kfree(*oid);
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*oid = NULL;
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return 0;
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}
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}
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return 1;
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}
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static int
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compare_oid(unsigned long *oid1, unsigned int oid1len,
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unsigned long *oid2, unsigned int oid2len)
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{
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unsigned int i;
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if (oid1len != oid2len)
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return 0;
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else {
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for (i = 0; i < oid1len; i++) {
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if (oid1[i] != oid2[i])
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return 0;
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}
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return 1;
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}
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}
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/* BB check for endian conversion issues here */
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int
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decode_negTokenInit(unsigned char *security_blob, int length,
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struct TCP_Server_Info *server)
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{
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struct asn1_ctx ctx;
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unsigned char *end;
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unsigned char *sequence_end;
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unsigned long *oid = NULL;
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unsigned int cls, con, tag, oidlen, rc;
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/* cifs_dump_mem(" Received SecBlob ", security_blob, length); */
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asn1_open(&ctx, security_blob, length);
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/* GSSAPI header */
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if (asn1_header_decode(&ctx, &end, &cls, &con, &tag) == 0) {
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cifs_dbg(FYI, "Error decoding negTokenInit header\n");
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return 0;
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} else if ((cls != ASN1_APL) || (con != ASN1_CON)
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|| (tag != ASN1_EOC)) {
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cifs_dbg(FYI, "cls = %d con = %d tag = %d\n", cls, con, tag);
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return 0;
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}
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/* Check for SPNEGO OID -- remember to free obj->oid */
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rc = asn1_header_decode(&ctx, &end, &cls, &con, &tag);
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if (rc) {
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if ((tag == ASN1_OJI) && (con == ASN1_PRI) &&
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(cls == ASN1_UNI)) {
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rc = asn1_oid_decode(&ctx, end, &oid, &oidlen);
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if (rc) {
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rc = compare_oid(oid, oidlen, SPNEGO_OID,
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SPNEGO_OID_LEN);
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kfree(oid);
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}
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} else
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rc = 0;
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}
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/* SPNEGO OID not present or garbled -- bail out */
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if (!rc) {
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cifs_dbg(FYI, "Error decoding negTokenInit header\n");
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return 0;
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}
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/* SPNEGO */
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if (asn1_header_decode(&ctx, &end, &cls, &con, &tag) == 0) {
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cifs_dbg(FYI, "Error decoding negTokenInit\n");
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return 0;
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} else if ((cls != ASN1_CTX) || (con != ASN1_CON)
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|| (tag != ASN1_EOC)) {
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cifs_dbg(FYI, "cls = %d con = %d tag = %d end = %p (%d) exit 0\n",
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cls, con, tag, end, *end);
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return 0;
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}
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/* negTokenInit */
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if (asn1_header_decode(&ctx, &end, &cls, &con, &tag) == 0) {
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cifs_dbg(FYI, "Error decoding negTokenInit\n");
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return 0;
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} else if ((cls != ASN1_UNI) || (con != ASN1_CON)
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|| (tag != ASN1_SEQ)) {
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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;
|
|
}
|