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alistair23-linux/fs/cifs/asn1.c
Jeff Layton e545937a51 [CIFS] add OIDs for KRB5 and MSKRB5 to ASN1 parsing routines 
Also, fix the parser to recognize them and set the secType
accordingly. Make CIFSSMBNegotiate not error out automatically
after parsing the securityBlob.

Also thanks to Q (Igor) and Simo for their help on this
set of kerberos patches (and Dave Howells for help on the
upcall).

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
2007-11-03 05:11:06 +00:00

634 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
* 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_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 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 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;
}
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--;
}
}
}
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;
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;
*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;
int use_ntlmssp = FALSE;
int use_kerberos = FALSE;
*secType = NTLM; /* BB eventually make Kerberos or NLTMSSP the default*/
/* cifs_dump_mem(" Received SecBlob ", security_blob, length); */
asn1_open(&ctx, security_blob, length);
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;
} else {
/* remember to free obj->oid */
rc = asn1_header_decode(&ctx, &end, &cls, &con, &tag);
if (rc) {
if ((tag == ASN1_OJI) && (cls == ASN1_PRI)) {
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;
}
if (!rc) {
cFYI(1, ("Error decoding negTokenInit header"));
return 0;
}
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;
}
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;
}
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;
}
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;
}
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_kerberos = TRUE;
else if (compare_oid(oid, oidlen,
KRB5_OID,
KRB5_OID_LEN))
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?"));
}
}
if (asn1_header_decode(&ctx, &end, &cls, &con, &tag) == 0) {
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;
}
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));
}
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;
}
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? */
}
if (use_kerberos)
*secType = Kerberos;
else if (use_ntlmssp)
*secType = NTLMSSP;
return 1;
}
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