diff mbox series

[v4] cifs: decoding negTokenInit with generic ASN1 decoder

Message ID 20210606010608.105516-1-hyc.lee@gmail.com
State New
Headers show
Series [v4] cifs: decoding negTokenInit with generic ASN1 decoder | expand

Commit Message

Hyunchul Lee June 6, 2021, 1:06 a.m. UTC
Decode negTokenInit with lib/asn1_decoder. For that,
add OIDs in linux/oid_registry.h and a negTokenInit
ASN1 file, "spnego_negtokeninit.asn1".
And define decoder's callback functions, which
are the gssapi_this_mech for checking SPENGO oid and
the neg_token_init_mech_type for getting authentication
mechanisms supported by a server.

Signed-off-by: Hyunchul Lee <hyc.lee@gmail.com>
---
changes from v3:
 - Change Makefile to fix a compile error, "spnego_negtokeninit.asn1.h: No such file or directory".
changes from v2:
 - Change Makefile to fix a compile error(kernel test bot).
 - Add cifsproto.h into asn1.c to fix a compile warning(kernel test bot).
chnages from v1:
 - Select CONFIG_OID_REGISTRY

 fs/cifs/Kconfig                  |   2 +
 fs/cifs/Makefile                 |   8 +-
 fs/cifs/asn1.c                   | 623 ++-----------------------------
 fs/cifs/spnego_negtokeninit.asn1 |  40 ++
 include/linux/oid_registry.h     |   8 +
 5 files changed, 93 insertions(+), 588 deletions(-)
 create mode 100644 fs/cifs/spnego_negtokeninit.asn1

Comments

Steve French June 6, 2021, 7:11 a.m. UTC | #1
"make M=fs/cifs"  from the top of the kernel tree worked, but my usual
script failed

"cd fs/cifs"
then
"make C=1 -C /usr/src/linux-headers-`uname -r` M=`pwd` modules
CF=-D__CHECK_ENDIAN__"

failed with (even after generating the files with the "make M=fs/cifs" earlier):

ASN.1   /home/smfrench/cifs-2.6/fs/cifs/spnego_negtokeninit.asn1.[ch]
  CC [M]  /home/smfrench/cifs-2.6/fs/cifs/asn1.o
/home/smfrench/cifs-2.6/fs/cifs/asn1.c: In function ‘gssapi_this_mech’:
/home/smfrench/cifs-2.6/fs/cifs/asn1.c:28:13: error: ‘OID_spnego’
undeclared (first use in this function)
   28 |  if (oid != OID_spnego) {
      |             ^~~~~~~~~~
/home/smfrench/cifs-2.6/fs/cifs/asn1.c:28:13: note: each undeclared
identifier is reported only once for each function it appears in
/home/smfrench/cifs-2.6/fs/cifs/asn1.c: In function ‘neg_token_init_mech_type’:
/home/smfrench/cifs-2.6/fs/cifs/asn1.c:47:13: error: ‘OID_mskrb5’
undeclared (first use in this function); did you mean ‘OID_md5’?
   47 |  if (oid == OID_mskrb5)
      |             ^~~~~~~~~~
      |             OID_md5
/home/smfrench/cifs-2.6/fs/cifs/asn1.c:49:18: error: ‘OID_krb5u2u’
undeclared (first use in this function)
   49 |  else if (oid == OID_krb5u2u)
      |                  ^~~~~~~~~~~
/home/smfrench/cifs-2.6/fs/cifs/asn1.c:51:18: error: ‘OID_krb5’
undeclared (first use in this function)
   51 |  else if (oid == OID_krb5)
      |                  ^~~~~~~~
/home/smfrench/cifs-2.6/fs/cifs/asn1.c:53:18: error: ‘OID_ntlmssp’
undeclared (first use in this function)
   53 |  else if (oid == OID_ntlmssp)
      |                  ^~~~~~~~~~~
make[1]: *** [scripts/Makefile.build:272:
/home/smfrench/cifs-2.6/fs/cifs/asn1.o] Error 1
make: *** [Makefile:1845: /home/smfrench/cifs-2.6/fs/cifs] Error 2
make: Leaving directory
'/usr/src/linux-headers-5.13.0-051300rc3daily20210526-generic

On Sat, Jun 5, 2021 at 8:07 PM Hyunchul Lee <hyc.lee@gmail.com> wrote:
>
> Decode negTokenInit with lib/asn1_decoder. For that,
> add OIDs in linux/oid_registry.h and a negTokenInit
> ASN1 file, "spnego_negtokeninit.asn1".
> And define decoder's callback functions, which
> are the gssapi_this_mech for checking SPENGO oid and
> the neg_token_init_mech_type for getting authentication
> mechanisms supported by a server.
>
> Signed-off-by: Hyunchul Lee <hyc.lee@gmail.com>
> ---
> changes from v3:
>  - Change Makefile to fix a compile error, "spnego_negtokeninit.asn1.h: No such file or directory".
> changes from v2:
>  - Change Makefile to fix a compile error(kernel test bot).
>  - Add cifsproto.h into asn1.c to fix a compile warning(kernel test bot).
> chnages from v1:
>  - Select CONFIG_OID_REGISTRY
>
>  fs/cifs/Kconfig                  |   2 +
>  fs/cifs/Makefile                 |   8 +-
>  fs/cifs/asn1.c                   | 623 ++-----------------------------
>  fs/cifs/spnego_negtokeninit.asn1 |  40 ++
>  include/linux/oid_registry.h     |   8 +
>  5 files changed, 93 insertions(+), 588 deletions(-)
>  create mode 100644 fs/cifs/spnego_negtokeninit.asn1
>
> diff --git a/fs/cifs/Kconfig b/fs/cifs/Kconfig
> index bf52e9326ebe..7de5c893c181 100644
> --- a/fs/cifs/Kconfig
> +++ b/fs/cifs/Kconfig
> @@ -19,6 +19,8 @@ config CIFS
>         select CRYPTO_LIB_DES
>         select KEYS
>         select DNS_RESOLVER
> +       select ASN1
> +       select OID_REGISTRY
>         help
>           This is the client VFS module for the SMB3 family of NAS protocols,
>           (including support for the most recent, most secure dialect SMB3.1.1)
> diff --git a/fs/cifs/Makefile b/fs/cifs/Makefile
> index 3ee3b7de4ded..9d877eafd350 100644
> --- a/fs/cifs/Makefile
> +++ b/fs/cifs/Makefile
> @@ -6,12 +6,16 @@ ccflags-y += -I$(src)         # needed for trace events
>  obj-$(CONFIG_CIFS) += cifs.o
>
>  cifs-y := trace.o cifsfs.o cifssmb.o cifs_debug.o connect.o dir.o file.o \
> -         inode.o link.o misc.o netmisc.o smbencrypt.o transport.o asn1.o \
> +         inode.o link.o misc.o netmisc.o smbencrypt.o transport.o \
>           cifs_unicode.o nterr.o cifsencrypt.o \
>           readdir.o ioctl.o sess.o export.o smb1ops.o unc.o winucase.o \
>           smb2ops.o smb2maperror.o smb2transport.o \
>           smb2misc.o smb2pdu.o smb2inode.o smb2file.o cifsacl.o fs_context.o \
> -         dns_resolve.o
> +         dns_resolve.o spnego_negtokeninit.asn1.o asn1.o
> +
> +$(obj)/asn1.o: $(obj)/spnego_negtokeninit.asn1.h
> +
> +$(obj)/spnego_negtokeninit.asn1.o: $(obj)/spnego_negtokeninit.asn1.c $(obj)/spnego_negtokeninit.asn1.h
>
>  cifs-$(CONFIG_CIFS_XATTR) += xattr.o
>
> diff --git a/fs/cifs/asn1.c b/fs/cifs/asn1.c
> index 3150c19cdc2f..2db95fe3abfb 100644
> --- a/fs/cifs/asn1.c
> +++ b/fs/cifs/asn1.c
> @@ -1,612 +1,63 @@
>  // 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 <linux/oid_registry.h>
>  #include "cifsglob.h"
>  #include "cifs_debug.h"
>  #include "cifsproto.h"
> +#include "spnego_negtokeninit.asn1.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)
> +int
> +decode_negTokenInit(unsigned char *security_blob, int length,
> +                   struct TCP_Server_Info *server)
>  {
> -       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;
> -               }
> +       if (asn1_ber_decoder(&spnego_negtokeninit_decoder, server,
> +                            security_blob, length) == 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)
> +int gssapi_this_mech(void *context, size_t hdrlen,
> +                    unsigned char tag, const void *value, size_t vlen)
>  {
> -       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;
> +       enum OID oid;
>
> -       while (ctx->pointer < eoc) {
> -               if (++(*len) > size) {
> -                       ctx->error = ASN1_ERR_DEC_BADVALUE;
> -                       kfree(*oid);
> -                       *oid = NULL;
> -                       return 0;
> -               }
> +       oid = look_up_OID(value, vlen);
> +       if (oid != OID_spnego) {
> +               char buf[50];
>
> -               if (!asn1_subid_decode(ctx, optr++)) {
> -                       kfree(*oid);
> -                       *oid = NULL;
> -                       return 0;
> -               }
> +               sprint_oid(value, vlen, buf, sizeof(buf));
> +               cifs_dbg(FYI, "Error decoding negTokenInit header: unexpected OID %s\n",
> +                        buf);
> +               return -EBADMSG;
>         }
> -       return 1;
> +       return 0;
>  }
>
> -static int
> -compare_oid(unsigned long *oid1, unsigned int oid1len,
> -           unsigned long *oid2, unsigned int oid2len)
> +int neg_token_init_mech_type(void *context, size_t hdrlen,
> +                            unsigned char tag,
> +                            const void *value, size_t vlen)
>  {
> -       unsigned int i;
> +       struct TCP_Server_Info *server = context;
> +       enum OID oid;
>
> -       if (oid1len != oid2len)
> -               return 0;
> +       oid = look_up_OID(value, vlen);
> +       if (oid == OID_mskrb5)
> +               server->sec_mskerberos = true;
> +       else if (oid == OID_krb5u2u)
> +               server->sec_kerberosu2u = true;
> +       else if (oid == OID_krb5)
> +               server->sec_kerberos = true;
> +       else if (oid == OID_ntlmssp)
> +               server->sec_ntlmssp = true;
>         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);
> +               char buf[50];
>
> -       /* 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;
> +               sprint_oid(value, vlen, buf, sizeof(buf));
> +               cifs_dbg(FYI, "Decoding negTokenInit: unsupported OID %s\n",
> +                        buf);
>         }
> -
> -       /* 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 exit 0\n",
> -                        cls, con, tag, 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 exit 1\n",
> -                        cls, con, tag, 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 exit 0\n",
> -                        cls, con, tag, 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 sequence_end = %p exit 1\n",
> -                        cls, con, tag, sequence_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;
> +       return 0;
>  }
> diff --git a/fs/cifs/spnego_negtokeninit.asn1 b/fs/cifs/spnego_negtokeninit.asn1
> new file mode 100644
> index 000000000000..aa5b4a61b3f5
> --- /dev/null
> +++ b/fs/cifs/spnego_negtokeninit.asn1
> @@ -0,0 +1,40 @@
> +GSSAPI ::=
> +       [APPLICATION 0] IMPLICIT SEQUENCE {
> +               thisMech
> +                       OBJECT IDENTIFIER ({gssapi_this_mech}),
> +               negotiationToken
> +                       NegotiationToken
> +       }
> +
> +MechType ::= OBJECT IDENTIFIER ({neg_token_init_mech_type})
> +
> +MechTypeList ::= SEQUENCE OF MechType
> +
> +NegHints ::= SEQUENCE {
> +       hintName
> +               [0] GeneralString OPTIONAL,
> +       hintAddress
> +               [1] OCTET STRING OPTIONAL
> +       }
> +
> +NegTokenInit2 ::=
> +       SEQUENCE {
> +               mechTypes
> +                       [0] MechTypeList OPTIONAL,
> +               reqFlags
> +                       [1] BIT STRING OPTIONAL,
> +               mechToken
> +                       [2] OCTET STRING OPTIONAL,
> +               negHints
> +                       [3] NegHints OPTIONAL,
> +               mechListMIC
> +                       [3] OCTET STRING OPTIONAL
> +       }
> +
> +NegotiationToken ::=
> +       CHOICE {
> +               negTokenInit
> +                       [0] NegTokenInit2,
> +               negTokenTarg
> +                       [1] ANY
> +       }
> diff --git a/include/linux/oid_registry.h b/include/linux/oid_registry.h
> index 461b7aa587ba..3d8db1f6a5db 100644
> --- a/include/linux/oid_registry.h
> +++ b/include/linux/oid_registry.h
> @@ -54,6 +54,10 @@ enum OID {
>         OID_md4,                        /* 1.2.840.113549.2.4 */
>         OID_md5,                        /* 1.2.840.113549.2.5 */
>
> +       OID_mskrb5,                     /* 1.2.840.48018.1.2.2 */
> +       OID_krb5,                       /* 1.2.840.113554.1.2.2 */
> +       OID_krb5u2u,                    /* 1.2.840.113554.1.2.2.3 */
> +
>         /* Microsoft Authenticode & Software Publishing */
>         OID_msIndirectData,             /* 1.3.6.1.4.1.311.2.1.4 */
>         OID_msStatementType,            /* 1.3.6.1.4.1.311.2.1.11 */
> @@ -62,6 +66,10 @@ enum OID {
>         OID_msIndividualSPKeyPurpose,   /* 1.3.6.1.4.1.311.2.1.21 */
>         OID_msOutlookExpress,           /* 1.3.6.1.4.1.311.16.4 */
>
> +       OID_ntlmssp,                    /* 1.3.6.1.4.1.311.2.2.10 */
> +
> +       OID_spnego,                     /* 1.3.6.1.5.5.2 */
> +
>         OID_certAuthInfoAccess,         /* 1.3.6.1.5.5.7.1.1 */
>         OID_sha1,                       /* 1.3.14.3.2.26 */
>         OID_id_ansip384r1,              /* 1.3.132.0.34 */
> --
> 2.25.1
>
Hyunchul Lee June 6, 2021, 7:52 a.m. UTC | #2
2021년 6월 6일 (일) 오후 4:11, Steve French <smfrench@gmail.com>님이 작성:
>
> "make M=fs/cifs"  from the top of the kernel tree worked, but my usual
> script failed
>
> "cd fs/cifs"
> then
> "make C=1 -C /usr/src/linux-headers-`uname -r` M=`pwd` modules
> CF=-D__CHECK_ENDIAN__"
>
> failed with (even after generating the files with the "make M=fs/cifs" earlier):
>
> ASN.1   /home/smfrench/cifs-2.6/fs/cifs/spnego_negtokeninit.asn1.[ch]
>   CC [M]  /home/smfrench/cifs-2.6/fs/cifs/asn1.o
> /home/smfrench/cifs-2.6/fs/cifs/asn1.c: In function ‘gssapi_this_mech’:
> /home/smfrench/cifs-2.6/fs/cifs/asn1.c:28:13: error: ‘OID_spnego’
> undeclared (first use in this function)
>    28 |  if (oid != OID_spnego) {
>       |             ^~~~~~~~~~

Because this patch have added some enum constants such as OID_spnego into
include/linux/oid_registry.h, compiling cifs with new linux headers is needed.

Thanks,
Hyunchul

> /home/smfrench/cifs-2.6/fs/cifs/asn1.c:28:13: note: each undeclared
> identifier is reported only once for each function it appears in
> /home/smfrench/cifs-2.6/fs/cifs/asn1.c: In function ‘neg_token_init_mech_type’:
> /home/smfrench/cifs-2.6/fs/cifs/asn1.c:47:13: error: ‘OID_mskrb5’
> undeclared (first use in this function); did you mean ‘OID_md5’?
>    47 |  if (oid == OID_mskrb5)
>       |             ^~~~~~~~~~
>       |             OID_md5
> /home/smfrench/cifs-2.6/fs/cifs/asn1.c:49:18: error: ‘OID_krb5u2u’
> undeclared (first use in this function)
>    49 |  else if (oid == OID_krb5u2u)
>       |                  ^~~~~~~~~~~
> /home/smfrench/cifs-2.6/fs/cifs/asn1.c:51:18: error: ‘OID_krb5’
> undeclared (first use in this function)
>    51 |  else if (oid == OID_krb5)
>       |                  ^~~~~~~~
> /home/smfrench/cifs-2.6/fs/cifs/asn1.c:53:18: error: ‘OID_ntlmssp’
> undeclared (first use in this function)
>    53 |  else if (oid == OID_ntlmssp)
>       |                  ^~~~~~~~~~~
> make[1]: *** [scripts/Makefile.build:272:
> /home/smfrench/cifs-2.6/fs/cifs/asn1.o] Error 1
> make: *** [Makefile:1845: /home/smfrench/cifs-2.6/fs/cifs] Error 2
> make: Leaving directory
> '/usr/src/linux-headers-5.13.0-051300rc3daily20210526-generic
>
> On Sat, Jun 5, 2021 at 8:07 PM Hyunchul Lee <hyc.lee@gmail.com> wrote:
> >
> > Decode negTokenInit with lib/asn1_decoder. For that,
> > add OIDs in linux/oid_registry.h and a negTokenInit
> > ASN1 file, "spnego_negtokeninit.asn1".
> > And define decoder's callback functions, which
> > are the gssapi_this_mech for checking SPENGO oid and
> > the neg_token_init_mech_type for getting authentication
> > mechanisms supported by a server.
> >
> > Signed-off-by: Hyunchul Lee <hyc.lee@gmail.com>
> > ---
> > changes from v3:
> >  - Change Makefile to fix a compile error, "spnego_negtokeninit.asn1.h: No such file or directory".
> > changes from v2:
> >  - Change Makefile to fix a compile error(kernel test bot).
> >  - Add cifsproto.h into asn1.c to fix a compile warning(kernel test bot).
> > chnages from v1:
> >  - Select CONFIG_OID_REGISTRY
> >
> >  fs/cifs/Kconfig                  |   2 +
> >  fs/cifs/Makefile                 |   8 +-
> >  fs/cifs/asn1.c                   | 623 ++-----------------------------
> >  fs/cifs/spnego_negtokeninit.asn1 |  40 ++
> >  include/linux/oid_registry.h     |   8 +
> >  5 files changed, 93 insertions(+), 588 deletions(-)
> >  create mode 100644 fs/cifs/spnego_negtokeninit.asn1
> >
> > diff --git a/fs/cifs/Kconfig b/fs/cifs/Kconfig
> > index bf52e9326ebe..7de5c893c181 100644
> > --- a/fs/cifs/Kconfig
> > +++ b/fs/cifs/Kconfig
> > @@ -19,6 +19,8 @@ config CIFS
> >         select CRYPTO_LIB_DES
> >         select KEYS
> >         select DNS_RESOLVER
> > +       select ASN1
> > +       select OID_REGISTRY
> >         help
> >           This is the client VFS module for the SMB3 family of NAS protocols,
> >           (including support for the most recent, most secure dialect SMB3.1.1)
> > diff --git a/fs/cifs/Makefile b/fs/cifs/Makefile
> > index 3ee3b7de4ded..9d877eafd350 100644
> > --- a/fs/cifs/Makefile
> > +++ b/fs/cifs/Makefile
> > @@ -6,12 +6,16 @@ ccflags-y += -I$(src)         # needed for trace events
> >  obj-$(CONFIG_CIFS) += cifs.o
> >
> >  cifs-y := trace.o cifsfs.o cifssmb.o cifs_debug.o connect.o dir.o file.o \
> > -         inode.o link.o misc.o netmisc.o smbencrypt.o transport.o asn1.o \
> > +         inode.o link.o misc.o netmisc.o smbencrypt.o transport.o \
> >           cifs_unicode.o nterr.o cifsencrypt.o \
> >           readdir.o ioctl.o sess.o export.o smb1ops.o unc.o winucase.o \
> >           smb2ops.o smb2maperror.o smb2transport.o \
> >           smb2misc.o smb2pdu.o smb2inode.o smb2file.o cifsacl.o fs_context.o \
> > -         dns_resolve.o
> > +         dns_resolve.o spnego_negtokeninit.asn1.o asn1.o
> > +
> > +$(obj)/asn1.o: $(obj)/spnego_negtokeninit.asn1.h
> > +
> > +$(obj)/spnego_negtokeninit.asn1.o: $(obj)/spnego_negtokeninit.asn1.c $(obj)/spnego_negtokeninit.asn1.h
> >
> >  cifs-$(CONFIG_CIFS_XATTR) += xattr.o
> >
> > diff --git a/fs/cifs/asn1.c b/fs/cifs/asn1.c
> > index 3150c19cdc2f..2db95fe3abfb 100644
> > --- a/fs/cifs/asn1.c
> > +++ b/fs/cifs/asn1.c
> > @@ -1,612 +1,63 @@
> >  // 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 <linux/oid_registry.h>
> >  #include "cifsglob.h"
> >  #include "cifs_debug.h"
> >  #include "cifsproto.h"
> > +#include "spnego_negtokeninit.asn1.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)
> > +int
> > +decode_negTokenInit(unsigned char *security_blob, int length,
> > +                   struct TCP_Server_Info *server)
> >  {
> > -       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;
> > -               }
> > +       if (asn1_ber_decoder(&spnego_negtokeninit_decoder, server,
> > +                            security_blob, length) == 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)
> > +int gssapi_this_mech(void *context, size_t hdrlen,
> > +                    unsigned char tag, const void *value, size_t vlen)
> >  {
> > -       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;
> > +       enum OID oid;
> >
> > -       while (ctx->pointer < eoc) {
> > -               if (++(*len) > size) {
> > -                       ctx->error = ASN1_ERR_DEC_BADVALUE;
> > -                       kfree(*oid);
> > -                       *oid = NULL;
> > -                       return 0;
> > -               }
> > +       oid = look_up_OID(value, vlen);
> > +       if (oid != OID_spnego) {
> > +               char buf[50];
> >
> > -               if (!asn1_subid_decode(ctx, optr++)) {
> > -                       kfree(*oid);
> > -                       *oid = NULL;
> > -                       return 0;
> > -               }
> > +               sprint_oid(value, vlen, buf, sizeof(buf));
> > +               cifs_dbg(FYI, "Error decoding negTokenInit header: unexpected OID %s\n",
> > +                        buf);
> > +               return -EBADMSG;
> >         }
> > -       return 1;
> > +       return 0;
> >  }
> >
> > -static int
> > -compare_oid(unsigned long *oid1, unsigned int oid1len,
> > -           unsigned long *oid2, unsigned int oid2len)
> > +int neg_token_init_mech_type(void *context, size_t hdrlen,
> > +                            unsigned char tag,
> > +                            const void *value, size_t vlen)
> >  {
> > -       unsigned int i;
> > +       struct TCP_Server_Info *server = context;
> > +       enum OID oid;
> >
> > -       if (oid1len != oid2len)
> > -               return 0;
> > +       oid = look_up_OID(value, vlen);
> > +       if (oid == OID_mskrb5)
> > +               server->sec_mskerberos = true;
> > +       else if (oid == OID_krb5u2u)
> > +               server->sec_kerberosu2u = true;
> > +       else if (oid == OID_krb5)
> > +               server->sec_kerberos = true;
> > +       else if (oid == OID_ntlmssp)
> > +               server->sec_ntlmssp = true;
> >         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);
> > +               char buf[50];
> >
> > -       /* 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;
> > +               sprint_oid(value, vlen, buf, sizeof(buf));
> > +               cifs_dbg(FYI, "Decoding negTokenInit: unsupported OID %s\n",
> > +                        buf);
> >         }
> > -
> > -       /* 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 exit 0\n",
> > -                        cls, con, tag, 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 exit 1\n",
> > -                        cls, con, tag, 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 exit 0\n",
> > -                        cls, con, tag, 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 sequence_end = %p exit 1\n",
> > -                        cls, con, tag, sequence_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;
> > +       return 0;
> >  }
> > diff --git a/fs/cifs/spnego_negtokeninit.asn1 b/fs/cifs/spnego_negtokeninit.asn1
> > new file mode 100644
> > index 000000000000..aa5b4a61b3f5
> > --- /dev/null
> > +++ b/fs/cifs/spnego_negtokeninit.asn1
> > @@ -0,0 +1,40 @@
> > +GSSAPI ::=
> > +       [APPLICATION 0] IMPLICIT SEQUENCE {
> > +               thisMech
> > +                       OBJECT IDENTIFIER ({gssapi_this_mech}),
> > +               negotiationToken
> > +                       NegotiationToken
> > +       }
> > +
> > +MechType ::= OBJECT IDENTIFIER ({neg_token_init_mech_type})
> > +
> > +MechTypeList ::= SEQUENCE OF MechType
> > +
> > +NegHints ::= SEQUENCE {
> > +       hintName
> > +               [0] GeneralString OPTIONAL,
> > +       hintAddress
> > +               [1] OCTET STRING OPTIONAL
> > +       }
> > +
> > +NegTokenInit2 ::=
> > +       SEQUENCE {
> > +               mechTypes
> > +                       [0] MechTypeList OPTIONAL,
> > +               reqFlags
> > +                       [1] BIT STRING OPTIONAL,
> > +               mechToken
> > +                       [2] OCTET STRING OPTIONAL,
> > +               negHints
> > +                       [3] NegHints OPTIONAL,
> > +               mechListMIC
> > +                       [3] OCTET STRING OPTIONAL
> > +       }
> > +
> > +NegotiationToken ::=
> > +       CHOICE {
> > +               negTokenInit
> > +                       [0] NegTokenInit2,
> > +               negTokenTarg
> > +                       [1] ANY
> > +       }
> > diff --git a/include/linux/oid_registry.h b/include/linux/oid_registry.h
> > index 461b7aa587ba..3d8db1f6a5db 100644
> > --- a/include/linux/oid_registry.h
> > +++ b/include/linux/oid_registry.h
> > @@ -54,6 +54,10 @@ enum OID {
> >         OID_md4,                        /* 1.2.840.113549.2.4 */
> >         OID_md5,                        /* 1.2.840.113549.2.5 */
> >
> > +       OID_mskrb5,                     /* 1.2.840.48018.1.2.2 */
> > +       OID_krb5,                       /* 1.2.840.113554.1.2.2 */
> > +       OID_krb5u2u,                    /* 1.2.840.113554.1.2.2.3 */
> > +
> >         /* Microsoft Authenticode & Software Publishing */
> >         OID_msIndirectData,             /* 1.3.6.1.4.1.311.2.1.4 */
> >         OID_msStatementType,            /* 1.3.6.1.4.1.311.2.1.11 */
> > @@ -62,6 +66,10 @@ enum OID {
> >         OID_msIndividualSPKeyPurpose,   /* 1.3.6.1.4.1.311.2.1.21 */
> >         OID_msOutlookExpress,           /* 1.3.6.1.4.1.311.16.4 */
> >
> > +       OID_ntlmssp,                    /* 1.3.6.1.4.1.311.2.2.10 */
> > +
> > +       OID_spnego,                     /* 1.3.6.1.5.5.2 */
> > +
> >         OID_certAuthInfoAccess,         /* 1.3.6.1.5.5.7.1.1 */
> >         OID_sha1,                       /* 1.3.14.3.2.26 */
> >         OID_id_ansip384r1,              /* 1.3.132.0.34 */
> > --
> > 2.25.1
> >
>
>
> --
> Thanks,
>
> Steve
diff mbox series

Patch

diff --git a/fs/cifs/Kconfig b/fs/cifs/Kconfig
index bf52e9326ebe..7de5c893c181 100644
--- a/fs/cifs/Kconfig
+++ b/fs/cifs/Kconfig
@@ -19,6 +19,8 @@  config CIFS
 	select CRYPTO_LIB_DES
 	select KEYS
 	select DNS_RESOLVER
+	select ASN1
+	select OID_REGISTRY
 	help
 	  This is the client VFS module for the SMB3 family of NAS protocols,
 	  (including support for the most recent, most secure dialect SMB3.1.1)
diff --git a/fs/cifs/Makefile b/fs/cifs/Makefile
index 3ee3b7de4ded..9d877eafd350 100644
--- a/fs/cifs/Makefile
+++ b/fs/cifs/Makefile
@@ -6,12 +6,16 @@  ccflags-y += -I$(src)		# needed for trace events
 obj-$(CONFIG_CIFS) += cifs.o
 
 cifs-y := trace.o cifsfs.o cifssmb.o cifs_debug.o connect.o dir.o file.o \
-	  inode.o link.o misc.o netmisc.o smbencrypt.o transport.o asn1.o \
+	  inode.o link.o misc.o netmisc.o smbencrypt.o transport.o \
 	  cifs_unicode.o nterr.o cifsencrypt.o \
 	  readdir.o ioctl.o sess.o export.o smb1ops.o unc.o winucase.o \
 	  smb2ops.o smb2maperror.o smb2transport.o \
 	  smb2misc.o smb2pdu.o smb2inode.o smb2file.o cifsacl.o fs_context.o \
-	  dns_resolve.o
+	  dns_resolve.o spnego_negtokeninit.asn1.o asn1.o
+
+$(obj)/asn1.o: $(obj)/spnego_negtokeninit.asn1.h
+
+$(obj)/spnego_negtokeninit.asn1.o: $(obj)/spnego_negtokeninit.asn1.c $(obj)/spnego_negtokeninit.asn1.h
 
 cifs-$(CONFIG_CIFS_XATTR) += xattr.o
 
diff --git a/fs/cifs/asn1.c b/fs/cifs/asn1.c
index 3150c19cdc2f..2db95fe3abfb 100644
--- a/fs/cifs/asn1.c
+++ b/fs/cifs/asn1.c
@@ -1,612 +1,63 @@ 
 // 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 <linux/oid_registry.h>
 #include "cifsglob.h"
 #include "cifs_debug.h"
 #include "cifsproto.h"
+#include "spnego_negtokeninit.asn1.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)
+int
+decode_negTokenInit(unsigned char *security_blob, int length,
+		    struct TCP_Server_Info *server)
 {
-	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;
-		}
+	if (asn1_ber_decoder(&spnego_negtokeninit_decoder, server,
+			     security_blob, length) == 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)
+int gssapi_this_mech(void *context, size_t hdrlen,
+		     unsigned char tag, const void *value, size_t vlen)
 {
-	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;
+	enum OID oid;
 
-	while (ctx->pointer < eoc) {
-		if (++(*len) > size) {
-			ctx->error = ASN1_ERR_DEC_BADVALUE;
-			kfree(*oid);
-			*oid = NULL;
-			return 0;
-		}
+	oid = look_up_OID(value, vlen);
+	if (oid != OID_spnego) {
+		char buf[50];
 
-		if (!asn1_subid_decode(ctx, optr++)) {
-			kfree(*oid);
-			*oid = NULL;
-			return 0;
-		}
+		sprint_oid(value, vlen, buf, sizeof(buf));
+		cifs_dbg(FYI, "Error decoding negTokenInit header: unexpected OID %s\n",
+			 buf);
+		return -EBADMSG;
 	}
-	return 1;
+	return 0;
 }
 
-static int
-compare_oid(unsigned long *oid1, unsigned int oid1len,
-	    unsigned long *oid2, unsigned int oid2len)
+int neg_token_init_mech_type(void *context, size_t hdrlen,
+			     unsigned char tag,
+			     const void *value, size_t vlen)
 {
-	unsigned int i;
+	struct TCP_Server_Info *server = context;
+	enum OID oid;
 
-	if (oid1len != oid2len)
-		return 0;
+	oid = look_up_OID(value, vlen);
+	if (oid == OID_mskrb5)
+		server->sec_mskerberos = true;
+	else if (oid == OID_krb5u2u)
+		server->sec_kerberosu2u = true;
+	else if (oid == OID_krb5)
+		server->sec_kerberos = true;
+	else if (oid == OID_ntlmssp)
+		server->sec_ntlmssp = true;
 	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);
+		char buf[50];
 
-	/* 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;
+		sprint_oid(value, vlen, buf, sizeof(buf));
+		cifs_dbg(FYI, "Decoding negTokenInit: unsupported OID %s\n",
+			 buf);
 	}
-
-	/* 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 exit 0\n",
-			 cls, con, tag, 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 exit 1\n",
-			 cls, con, tag, 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 exit 0\n",
-			 cls, con, tag, 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 sequence_end = %p exit 1\n",
-			 cls, con, tag, sequence_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;
+	return 0;
 }
diff --git a/fs/cifs/spnego_negtokeninit.asn1 b/fs/cifs/spnego_negtokeninit.asn1
new file mode 100644
index 000000000000..aa5b4a61b3f5
--- /dev/null
+++ b/fs/cifs/spnego_negtokeninit.asn1
@@ -0,0 +1,40 @@ 
+GSSAPI ::=
+	[APPLICATION 0] IMPLICIT SEQUENCE {
+		thisMech
+			OBJECT IDENTIFIER ({gssapi_this_mech}),
+		negotiationToken
+			NegotiationToken
+	}
+
+MechType ::= OBJECT IDENTIFIER ({neg_token_init_mech_type})
+
+MechTypeList ::= SEQUENCE OF MechType
+
+NegHints ::= SEQUENCE {
+	hintName
+		[0] GeneralString OPTIONAL,
+	hintAddress
+		[1] OCTET STRING OPTIONAL
+	}
+
+NegTokenInit2 ::=
+	SEQUENCE {
+		mechTypes
+			[0] MechTypeList OPTIONAL,
+		reqFlags
+			[1] BIT STRING OPTIONAL,
+		mechToken
+			[2] OCTET STRING OPTIONAL,
+		negHints
+			[3] NegHints OPTIONAL,
+		mechListMIC
+			[3] OCTET STRING OPTIONAL
+	}
+
+NegotiationToken ::=
+	CHOICE {
+		negTokenInit
+			[0] NegTokenInit2,
+		negTokenTarg
+			[1] ANY
+	}
diff --git a/include/linux/oid_registry.h b/include/linux/oid_registry.h
index 461b7aa587ba..3d8db1f6a5db 100644
--- a/include/linux/oid_registry.h
+++ b/include/linux/oid_registry.h
@@ -54,6 +54,10 @@  enum OID {
 	OID_md4,			/* 1.2.840.113549.2.4 */
 	OID_md5,			/* 1.2.840.113549.2.5 */
 
+	OID_mskrb5,			/* 1.2.840.48018.1.2.2 */
+	OID_krb5,			/* 1.2.840.113554.1.2.2 */
+	OID_krb5u2u,			/* 1.2.840.113554.1.2.2.3 */
+
 	/* Microsoft Authenticode & Software Publishing */
 	OID_msIndirectData,		/* 1.3.6.1.4.1.311.2.1.4 */
 	OID_msStatementType,		/* 1.3.6.1.4.1.311.2.1.11 */
@@ -62,6 +66,10 @@  enum OID {
 	OID_msIndividualSPKeyPurpose,	/* 1.3.6.1.4.1.311.2.1.21 */
 	OID_msOutlookExpress,		/* 1.3.6.1.4.1.311.16.4 */
 
+	OID_ntlmssp,			/* 1.3.6.1.4.1.311.2.2.10 */
+
+	OID_spnego,			/* 1.3.6.1.5.5.2 */
+
 	OID_certAuthInfoAccess,		/* 1.3.6.1.5.5.7.1.1 */
 	OID_sha1,			/* 1.3.14.3.2.26 */
 	OID_id_ansip384r1,		/* 1.3.132.0.34 */