1 files changed, 650 insertions, 650 deletions

diff --git a/linden/indra/libgcrypt/libgcrypt-1.2.2/mpi/mpicoder.c b/linden/indra/libgcrypt/libgcrypt-1.2.2/mpi/mpicoder.c
index ba0255c..4a90850 100755..100644
--- a/linden/indra/libgcrypt/libgcrypt-1.2.2/mpi/mpicoder.c
+++ b/linden/indra/libgcrypt/libgcrypt-1.2.2/mpi/mpicoder.c
@@ -1,650 +1,650 @@
-/* mpicoder.c  -  Coder for the external representation of MPIs

- * Copyright (C) 1998, 1999, 2000, 2001, 2002,

- *               2003 Free Software Foundation, Inc.

- *

- * This file is part of Libgcrypt.

- *

- * Libgcrypt is free software; you can redistribute it and/or modify

- * it under the terms of the GNU Lesser General Public License as

- * published by the Free Software Foundation; either version 2.1 of

- * the License, or (at your option) any later version.

- *

- * Libgcrypt 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 Lesser General Public License for more details.

- *

- * You should have received a copy of the GNU Lesser 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 <config.h>

-#include <stdio.h>

-#include <string.h>

-#include <stdlib.h>

-#include <assert.h>

-

-#include "mpi-internal.h"

-#include "g10lib.h"

-

-#define MAX_EXTERN_MPI_BITS 16384

-

-

-static gcry_mpi_t

-mpi_read_from_buffer (const unsigned char *buffer, unsigned int *ret_nread,

-                      int secure)

-{

-  int i, j;

-  unsigned int nbits, nbytes, nlimbs, nread=0;

-  mpi_limb_t a;

-  gcry_mpi_t val = MPI_NULL;

-

-  if (*ret_nread < 2)

-    goto leave;

-  nbits = buffer[0] << 8 | buffer[1];

-  if (nbits > MAX_EXTERN_MPI_BITS) 

-    {

-      log_error ("mpi too large (%u bits)\n", nbits);

-      goto leave;

-    }

-  else if (!nbits) 

-    {

-      log_error ("an mpi of size 0 is not allowed\n");

-      goto leave;

-    }

-  buffer += 2;

-  nread = 2;

-  

-  nbytes = (nbits+7) / 8;

-  nlimbs = (nbytes+BYTES_PER_MPI_LIMB-1) / BYTES_PER_MPI_LIMB;

-  val = secure? mpi_alloc_secure( nlimbs )

-    : mpi_alloc( nlimbs );

-  i = BYTES_PER_MPI_LIMB - nbytes % BYTES_PER_MPI_LIMB;

-  i %= BYTES_PER_MPI_LIMB;

-  j= val->nlimbs = nlimbs;

-  val->sign = 0;

-  for( ; j > 0; j-- ) 

-    {

-      a = 0;

-      for (; i < BYTES_PER_MPI_LIMB; i++ )

-        {

-          if ( ++nread > *ret_nread )

-            log_bug ("mpi larger than buffer");

-          a <<= 8;

-          a |= *buffer++;

-        }

-      i = 0;

-      val->d[j-1] = a;

-    }

-

- leave:

-  *ret_nread = nread;

-  return val;

-}

-

-

-/****************

- * Make an mpi from a hex character string.

- */

-static int

-mpi_fromstr(gcry_mpi_t val, const char *str)

-{

-    int sign=0, prepend_zero=0, i, j, c, c1, c2;

-    unsigned nbits, nbytes, nlimbs;

-    mpi_limb_t a;

-

-    if( *str == '-' ) {

-        sign = 1;

-        str++;

-    }

-

-    /* skip optional hex prefix */

-    if ( *str == '0' && str[1] == 'x' ) {

-        str += 2;

-    }

-

-    nbits = strlen(str)*4;

-    if( nbits % 8 )

-        prepend_zero = 1;

-    nbytes = (nbits+7) / 8;

-    nlimbs = (nbytes+BYTES_PER_MPI_LIMB-1) / BYTES_PER_MPI_LIMB;

-    if( val->alloced < nlimbs )

-        mpi_resize(val, nlimbs );

-    i = BYTES_PER_MPI_LIMB - nbytes % BYTES_PER_MPI_LIMB;

-    i %= BYTES_PER_MPI_LIMB;

-    j= val->nlimbs = nlimbs;

-    val->sign = sign;

-    for( ; j > 0; j-- ) {

-        a = 0;

-        for(; i < BYTES_PER_MPI_LIMB; i++ ) {

-            if( prepend_zero ) {

-                c1 = '0';

-                prepend_zero = 0;

-            }

-            else

-                c1 = *str++;

-            assert(c1);

-            c2 = *str++;

-            assert(c2);

-            if( c1 >= '0' && c1 <= '9' )

-                c = c1 - '0';

-            else if( c1 >= 'a' && c1 <= 'f' )

-                c = c1 - 'a' + 10;

-            else if( c1 >= 'A' && c1 <= 'F' )

-                c = c1 - 'A' + 10;

-            else {

-                mpi_clear(val);

-                return 1;

-            }

-            c <<= 4;

-            if( c2 >= '0' && c2 <= '9' )

-                c |= c2 - '0';

-            else if( c2 >= 'a' && c2 <= 'f' )

-                c |= c2 - 'a' + 10;

-            else if( c2 >= 'A' && c2 <= 'F' )

-                c |= c2 - 'A' + 10;

-            else {

-                mpi_clear(val);

-                return 1;

-            }

-            a <<= 8;

-            a |= c;

-        }

-        i = 0;

-        val->d[j-1] = a;

-    }

-

-    return 0;

-}

-

-

-/* Dump the value of A in a format suitable for debugging to

-   Libgcrypt's logging stream.  Note that one leading space but no

-   trailing space or linefeed will be printed.  It is okay to pass

-   NULL for A. */

-void 

-gcry_mpi_dump (const gcry_mpi_t a)

-{

-  int i;

-

-  log_printf (" ");

-  if (!a)

-    log_printf ("[MPI_NULL]");

-  else 

-    {

-      if (a->sign)

-        log_printf ( "-");

-#if BYTES_PER_MPI_LIMB == 2

-# define X "4"

-#elif BYTES_PER_MPI_LIMB == 4

-# define X "8"

-#elif BYTES_PER_MPI_LIMB == 8

-# define X "16"

-#elif BYTES_PER_MPI_LIMB == 16

-# define X "32"

-#else

-# error please define the format here

-#endif

-      for (i=a->nlimbs; i > 0 ; i-- )

-        {

-          log_printf (i != a->nlimbs? "%0" X "lX":"%lX", (ulong)a->d[i-1]);

-        }

-#undef X

-      if (!a->nlimbs)

-        log_printf ("0");

-    }

-}

-

-/* Convience function used internally. */

-void

-_gcry_log_mpidump (const char *text, gcry_mpi_t a)

-{

-  log_printf ("%s:", text);

-  gcry_mpi_dump (a);

-  log_printf ("\n");

-}

-

-

-/****************

- * Return an m_alloced buffer with the MPI (msb first).

- * NBYTES receives the length of this buffer. Caller must free the

- * return string (This function does return a 0 byte buffer with NBYTES

- * set to zero if the value of A is zero. If sign is not NULL, it will

- * be set to the sign of the A.

- */

-static byte *

-do_get_buffer( gcry_mpi_t a, unsigned *nbytes, int *sign, int force_secure )

-{

-    byte *p, *buffer;

-    mpi_limb_t alimb;

-    int i;

-    size_t n;

-

-    if( sign )

-        *sign = a->sign;

-    *nbytes = a->nlimbs * BYTES_PER_MPI_LIMB;

-    n = *nbytes? *nbytes:1; /* allocate at least one byte */

-    p = buffer = force_secure || mpi_is_secure(a) ? gcry_xmalloc_secure(n)

-                                                  : gcry_xmalloc(n);

-

-    for(i=a->nlimbs-1; i >= 0; i-- ) {

-        alimb = a->d[i];

-#if BYTES_PER_MPI_LIMB == 4

-        *p++ = alimb >> 24;

-        *p++ = alimb >> 16;

-        *p++ = alimb >>  8;

-        *p++ = alimb      ;

-#elif BYTES_PER_MPI_LIMB == 8

-        *p++ = alimb >> 56;

-        *p++ = alimb >> 48;

-        *p++ = alimb >> 40;

-        *p++ = alimb >> 32;

-        *p++ = alimb >> 24;

-        *p++ = alimb >> 16;

-        *p++ = alimb >>  8;

-        *p++ = alimb      ;

-#else

-        #error please implement for this limb size.

-#endif

-    }

-

-    /* this is sub-optimal but we need to do the shift oepration because

-     * the caller has to free the returned buffer */

-    for(p=buffer; !*p && *nbytes; p++, --*nbytes )

-        ;

-    if( p != buffer )

-        memmove(buffer,p, *nbytes);

-    return buffer;

-}

-

-

-byte *

-_gcry_mpi_get_buffer( gcry_mpi_t a, unsigned *nbytes, int *sign )

-{

-    return do_get_buffer( a, nbytes, sign, 0 );

-}

-

-byte *

-_gcry_mpi_get_secure_buffer( gcry_mpi_t a, unsigned *nbytes, int *sign )

-{

-    return do_get_buffer( a, nbytes, sign, 1 );

-}

-

-/****************

- * Use BUFFER to update MPI.

- */

-void

-_gcry_mpi_set_buffer( gcry_mpi_t a, const byte *buffer, unsigned nbytes, int sign )

-{

-    const byte *p;

-    mpi_limb_t alimb;

-    int nlimbs;

-    int i;

-

-    nlimbs = (nbytes + BYTES_PER_MPI_LIMB - 1) / BYTES_PER_MPI_LIMB;

-    RESIZE_IF_NEEDED(a, nlimbs);

-    a->sign = sign;

-

-    for(i=0, p = buffer+nbytes-1; p >= buffer+BYTES_PER_MPI_LIMB; ) {

-#if BYTES_PER_MPI_LIMB == 4

-        alimb  = *p--       ;

-        alimb |= *p-- <<  8 ;

-        alimb |= *p-- << 16 ;

-        alimb |= *p-- << 24 ;

-#elif BYTES_PER_MPI_LIMB == 8

-        alimb  = (mpi_limb_t)*p--       ;

-        alimb |= (mpi_limb_t)*p-- <<  8 ;

-        alimb |= (mpi_limb_t)*p-- << 16 ;

-        alimb |= (mpi_limb_t)*p-- << 24 ;

-        alimb |= (mpi_limb_t)*p-- << 32 ;

-        alimb |= (mpi_limb_t)*p-- << 40 ;

-        alimb |= (mpi_limb_t)*p-- << 48 ;

-        alimb |= (mpi_limb_t)*p-- << 56 ;

-#else

-        #error please implement for this limb size.

-#endif

-        a->d[i++] = alimb;

-    }

-    if( p >= buffer ) {

-#if BYTES_PER_MPI_LIMB == 4

-        alimb  = *p--       ;

-        if( p >= buffer ) alimb |= *p-- <<  8 ;

-        if( p >= buffer ) alimb |= *p-- << 16 ;

-        if( p >= buffer ) alimb |= *p-- << 24 ;

-#elif BYTES_PER_MPI_LIMB == 8

-        alimb  = (mpi_limb_t)*p-- ;

-        if( p >= buffer ) alimb |= (mpi_limb_t)*p-- <<  8 ;

-        if( p >= buffer ) alimb |= (mpi_limb_t)*p-- << 16 ;

-        if( p >= buffer ) alimb |= (mpi_limb_t)*p-- << 24 ;

-        if( p >= buffer ) alimb |= (mpi_limb_t)*p-- << 32 ;

-        if( p >= buffer ) alimb |= (mpi_limb_t)*p-- << 40 ;

-        if( p >= buffer ) alimb |= (mpi_limb_t)*p-- << 48 ;

-        if( p >= buffer ) alimb |= (mpi_limb_t)*p-- << 56 ;

-#else

-        #error please implement for this limb size.

-#endif

-        a->d[i++] = alimb;

-    }

-    a->nlimbs = i;

-    assert( i == nlimbs );

-}

-

-

-

-/* Convert the external representation of an integer stored in BUFFER

-   with a length of BUFLEN into a newly create MPI returned in

-   RET_MPI.  If NBYTES is not NULL, it will receive the number of

-   bytes actually scanned after a successful operation. */

-gcry_error_t

-gcry_mpi_scan( struct gcry_mpi **ret_mpi, enum gcry_mpi_format format,

-               const void *buffer_arg, size_t buflen, size_t *nscanned )

-{

-    const unsigned char *buffer = (const unsigned char*)buffer_arg;

-    struct gcry_mpi *a = NULL;

-    unsigned int len;

-    int secure = (buffer && gcry_is_secure (buffer));

-

-    if (format == GCRYMPI_FMT_SSH)

-      len = 0;

-    else

-      len = buflen;

-

-    if( format == GCRYMPI_FMT_STD ) {

-        const byte *s = buffer;

-

-        a = secure? mpi_alloc_secure ((len+BYTES_PER_MPI_LIMB-1)

-                                      /BYTES_PER_MPI_LIMB)

-                  : mpi_alloc ((len+BYTES_PER_MPI_LIMB-1)/BYTES_PER_MPI_LIMB);

-        if( len ) { /* not zero */

-            a->sign = *s & 0x80;

-            if( a->sign ) {

-                /* FIXME: we have to convert from 2compl to magnitude format */

-                mpi_free(a);

-                return gcry_error (GPG_ERR_INTERNAL);

-            }

-            else

-                _gcry_mpi_set_buffer( a, s, len, 0 );

-        }

-        if( ret_mpi ) {

-            mpi_normalize ( a );

-            *ret_mpi = a;

-        }

-        else

-            mpi_free(a);

-        return gcry_error (GPG_ERR_NO_ERROR);

-    }

-    else if( format == GCRYMPI_FMT_USG ) {

-        a = secure? mpi_alloc_secure ((len+BYTES_PER_MPI_LIMB-1)

-                                      /BYTES_PER_MPI_LIMB)

-                  : mpi_alloc ((len+BYTES_PER_MPI_LIMB-1)/BYTES_PER_MPI_LIMB);

-

-        if( len )  /* not zero */

-            _gcry_mpi_set_buffer( a, buffer, len, 0 );

-        if( ret_mpi ) {

-            mpi_normalize ( a );

-            *ret_mpi = a;

-        }

-        else

-            mpi_free(a);

-        return gcry_error (GPG_ERR_NO_ERROR);

-    }

-    else if( format == GCRYMPI_FMT_PGP ) {

-        a = mpi_read_from_buffer (buffer, &len, secure);

-        if( nscanned )

-            *nscanned = len;

-        if( ret_mpi && a ) {

-            mpi_normalize ( a );

-            *ret_mpi = a;

-        }

-        else

-            mpi_free(a);

-        return gcry_error (a ? GPG_ERR_NO_ERROR : GPG_ERR_INV_OBJ);

-    }

-    else if( format == GCRYMPI_FMT_SSH ) {

-        const unsigned char *s = buffer;

-        size_t n;

-

-        if( len && len < 4 )

-            return gcry_error (GPG_ERR_TOO_SHORT);

-        n = s[0] << 24 | s[1] << 16 | s[2] << 8 | s[3];

-        s += 4; 

-        if (len)

-          len -= 4;

-        if( len && n > len )

-            return gcry_error (GPG_ERR_TOO_LARGE); /* or should it be

-                                                      too_short */

-

-        a = secure? mpi_alloc_secure ((n+BYTES_PER_MPI_LIMB-1)

-                                      /BYTES_PER_MPI_LIMB)

-                  : mpi_alloc ((n+BYTES_PER_MPI_LIMB-1)/BYTES_PER_MPI_LIMB);

-        if( n ) { /* not zero */

-            a->sign = *s & 0x80;

-            if( a->sign ) {

-                /* FIXME: we have to convert from 2compl to magnitude format */

-                mpi_free(a);

-                return gcry_error (GPG_ERR_INTERNAL);

-            }

-            else

-                _gcry_mpi_set_buffer( a, s, n, 0 );

-        }

-        if( nscanned )

-            *nscanned = n+4;

-        if( ret_mpi ) {

-            mpi_normalize ( a );

-            *ret_mpi = a;

-        }

-        else

-            mpi_free(a);

-        return gcry_error (GPG_ERR_NO_ERROR);

-    }

-    else if( format == GCRYMPI_FMT_HEX ) {

-        if( buflen )

-            return gcry_error (GPG_ERR_INV_ARG); /* can only handle C

-                                                    strings for now */

-        a = secure? mpi_alloc_secure (0) : mpi_alloc(0);

-        if( mpi_fromstr ( a, (const char *)buffer ) )

-            return gcry_error (GPG_ERR_INV_OBJ);

-        if( ret_mpi ) {

-            mpi_normalize ( a );

-            *ret_mpi = a;

-        }

-        else

-            mpi_free(a);

-        return gcry_error (GPG_ERR_NO_ERROR);

-    }

-    else

-        return gcry_error (GPG_ERR_INV_ARG);

-}

-

-/* Convert the big integer A into the external representation

-   described by FORMAT and store it in the provided BUFFER which has

-   been allocated by the user with a size of BUFLEN bytes.  NWRITTEN

-   receives the actual length of the external representation unless it

-   has been passed as NULL.  BUFFER may be NULL to query the required

-   length.*/

-gcry_error_t

-gcry_mpi_print( enum gcry_mpi_format format,

-                unsigned char *buffer, size_t buflen,

-                size_t *nwritten, struct gcry_mpi *a)

-{

-    unsigned int nbits = mpi_get_nbits(a);

-    size_t len;

-    size_t dummy_nwritten;

-

-    if (!nwritten)

-      nwritten = &dummy_nwritten;

-

-    len = buflen;

-    *nwritten = 0;

-    if( format == GCRYMPI_FMT_STD ) {

-        unsigned char *tmp;

-        int extra = 0;

-        unsigned int n;

-

-        if( a->sign )

-            return gcry_error (GPG_ERR_INTERNAL); /* can't handle it yet */

-

-        tmp = _gcry_mpi_get_buffer( a, &n, NULL );

-        if( n && (*tmp & 0x80) ) {

-            n++;

-            extra=1;

-        }

-

-        if (buffer && n > len) {

-            /* The provided buffer is too short. */

-            gcry_free(tmp);

-            return gcry_error (GPG_ERR_TOO_SHORT);  

-        }

-        if( buffer ) {

-            byte *s = buffer;

-            if( extra )

-                *s++ = 0;

-

-            memcpy( s, tmp, n-extra );

-        }

-        gcry_free(tmp);

-        *nwritten = n;

-        return gcry_error (GPG_ERR_NO_ERROR);

-    }

-    else if( format == GCRYMPI_FMT_USG ) {

-        unsigned int n = (nbits + 7)/8;

-

-        /* we ignore the sign for this format */

-        /* FIXME: for performance reasons we should put this into

-         * mpi_aprint becuase we can then use the buffer directly */

-        if (buffer && n > len)

-            return gcry_error (GPG_ERR_TOO_SHORT);  /* the provided buffer is too short */

-        if( buffer ) {

-            unsigned char *tmp;

-            tmp = _gcry_mpi_get_buffer( a, &n, NULL );

-            memcpy( buffer, tmp, n );

-            gcry_free(tmp);

-        }

-        *nwritten = n;

-        return gcry_error (GPG_ERR_NO_ERROR);

-    }

-    else if( format == GCRYMPI_FMT_PGP ) {

-        unsigned int n = (nbits + 7)/8;

-

-        if( a->sign )

-            return gcry_error (GPG_ERR_INV_ARG); /* pgp format can only handle unsigned */

-

-        if (buffer && n+2 > len)

-            return gcry_error (GPG_ERR_TOO_SHORT);  /* the provided buffer is too short */

-        if( buffer ) {

-            unsigned char *tmp;

-            unsigned char *s = buffer;

-            s[0] = nbits >> 8;

-            s[1] = nbits;

-

-            tmp = _gcry_mpi_get_buffer( a, &n, NULL );

-            memcpy( s+2, tmp, n );

-            gcry_free(tmp);

-        }

-        *nwritten = n+2;

-        return gcry_error (GPG_ERR_NO_ERROR);

-    }

-    else if( format == GCRYMPI_FMT_SSH ) {

-        unsigned char *tmp;

-        int extra = 0;

-        unsigned int n;

-

-        if( a->sign )

-            return gcry_error (GPG_ERR_INTERNAL); /* can't handle it yet */

-

-        tmp = _gcry_mpi_get_buffer( a, &n, NULL );

-        if( n && (*tmp & 0x80) ) {

-            n++;

-            extra=1;

-        }

-

-        if (buffer && n+4 > len) {

-            gcry_free(tmp);

-            return gcry_error (GPG_ERR_TOO_SHORT);  /* the provided buffer is too short */

-        }

-        if( buffer ) {

-            byte *s = buffer;

-            *s++ = n >> 24;

-            *s++ = n >> 16;

-            *s++ = n >> 8;

-            *s++ = n;

-            if( extra )

-                *s++ = 0;

-

-            memcpy( s, tmp, n-extra );

-        }

-        gcry_free(tmp);

-        *nwritten = 4+n;

-        return gcry_error (GPG_ERR_NO_ERROR);

-    }

-    else if( format == GCRYMPI_FMT_HEX ) {

-        byte *tmp;

-        int i;

-        int extra = 0;

-        unsigned int n=0;

-

-        tmp = _gcry_mpi_get_buffer( a, &n, NULL );

-        if( !n || (*tmp & 0x80) )

-            extra=2;

-

-        if(buffer && 2*n + extra + !!a->sign + 1 > len) {

-            gcry_free(tmp);

-            return gcry_error (GPG_ERR_TOO_SHORT);  /* the provided buffer is too short */

-        }

-        if( buffer ) {

-            byte *s = buffer;

-            if( a->sign )

-                *s++ = '-';

-            if( extra ) {

-                *s++ = '0';

-                *s++ = '0';

-            }

-

-            for(i=0; i < n; i++ ) {

-                unsigned int c = tmp[i];

-                *s++ = (c >> 4) < 10? '0'+(c>>4) : 'A'+(c>>4)-10 ;

-                c &= 15;

-                *s++ = c < 10? '0'+c : 'A'+c-10 ;

-            }

-            *s++ = 0;

-            *nwritten = s - buffer;

-        }

-        else {

-            *nwritten = 2*n + extra + !!a->sign + 1;

-        }

-        gcry_free(tmp);

-        return gcry_error (GPG_ERR_NO_ERROR);

-    }

-    else

-        return gcry_error (GPG_ERR_INV_ARG);

-}

-

-/****************

- * Like gcry_mpi_print but this function allocates the buffer itself.

- * The caller has to supply the address of a pointer. NWRITTEN may be

- * NULL.

- */

-gcry_error_t

-gcry_mpi_aprint( enum gcry_mpi_format format,

-                 unsigned char **buffer, size_t *nwritten,

-                 struct gcry_mpi *a )

-{

-    size_t n;

-    gcry_error_t rc;

-

-    *buffer = NULL;

-    rc = gcry_mpi_print( format, NULL, 0, &n, a );

-    if( rc )

-        return rc;

-    *buffer = mpi_is_secure(a) ? gcry_xmalloc_secure( n ) : gcry_xmalloc( n );

-    rc = gcry_mpi_print( format, *buffer, n, &n, a );

-    if( rc ) {

-        gcry_free(*buffer);

-        *buffer = NULL;

-    }

-    else if( nwritten )

-        *nwritten = n;

-    return rc;

-}

-

+/* mpicoder.c  -  Coder for the external representation of MPIs
+ * Copyright (C) 1998, 1999, 2000, 2001, 2002,
+ *               2003 Free Software Foundation, Inc.
+ *
+ * This file is part of Libgcrypt.
+ *
+ * Libgcrypt is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as
+ * published by the Free Software Foundation; either version 2.1 of
+ * the License, or (at your option) any later version.
+ *
+ * Libgcrypt 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 Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser 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 <config.h>
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <assert.h>
+
+#include "mpi-internal.h"
+#include "g10lib.h"
+
+#define MAX_EXTERN_MPI_BITS 16384
+
+
+static gcry_mpi_t
+mpi_read_from_buffer (const unsigned char *buffer, unsigned int *ret_nread,
+                      int secure)
+{
+  int i, j;
+  unsigned int nbits, nbytes, nlimbs, nread=0;
+  mpi_limb_t a;
+  gcry_mpi_t val = MPI_NULL;
+
+  if (*ret_nread < 2)
+    goto leave;
+  nbits = buffer[0] << 8 | buffer[1];
+  if (nbits > MAX_EXTERN_MPI_BITS) 
+    {
+      log_error ("mpi too large (%u bits)\n", nbits);
+      goto leave;
+    }
+  else if (!nbits) 
+    {
+      log_error ("an mpi of size 0 is not allowed\n");
+      goto leave;
+    }
+  buffer += 2;
+  nread = 2;
+  
+  nbytes = (nbits+7) / 8;
+  nlimbs = (nbytes+BYTES_PER_MPI_LIMB-1) / BYTES_PER_MPI_LIMB;
+  val = secure? mpi_alloc_secure( nlimbs )
+    : mpi_alloc( nlimbs );
+  i = BYTES_PER_MPI_LIMB - nbytes % BYTES_PER_MPI_LIMB;
+  i %= BYTES_PER_MPI_LIMB;
+  j= val->nlimbs = nlimbs;
+  val->sign = 0;
+  for( ; j > 0; j-- ) 
+    {
+      a = 0;
+      for (; i < BYTES_PER_MPI_LIMB; i++ )
+        {
+          if ( ++nread > *ret_nread )
+            log_bug ("mpi larger than buffer");
+          a <<= 8;
+          a |= *buffer++;
+        }
+      i = 0;
+      val->d[j-1] = a;
+    }
+
+ leave:
+  *ret_nread = nread;
+  return val;
+}
+
+
+/****************
+ * Make an mpi from a hex character string.
+ */
+static int
+mpi_fromstr(gcry_mpi_t val, const char *str)
+{
+    int sign=0, prepend_zero=0, i, j, c, c1, c2;
+    unsigned nbits, nbytes, nlimbs;
+    mpi_limb_t a;
+
+    if( *str == '-' ) {
+        sign = 1;
+        str++;
+    }
+
+    /* skip optional hex prefix */
+    if ( *str == '0' && str[1] == 'x' ) {
+        str += 2;
+    }
+
+    nbits = strlen(str)*4;
+    if( nbits % 8 )
+        prepend_zero = 1;
+    nbytes = (nbits+7) / 8;
+    nlimbs = (nbytes+BYTES_PER_MPI_LIMB-1) / BYTES_PER_MPI_LIMB;
+    if( val->alloced < nlimbs )
+        mpi_resize(val, nlimbs );
+    i = BYTES_PER_MPI_LIMB - nbytes % BYTES_PER_MPI_LIMB;
+    i %= BYTES_PER_MPI_LIMB;
+    j= val->nlimbs = nlimbs;
+    val->sign = sign;
+    for( ; j > 0; j-- ) {
+        a = 0;
+        for(; i < BYTES_PER_MPI_LIMB; i++ ) {
+            if( prepend_zero ) {
+                c1 = '0';
+                prepend_zero = 0;
+            }
+            else
+                c1 = *str++;
+            assert(c1);
+            c2 = *str++;
+            assert(c2);
+            if( c1 >= '0' && c1 <= '9' )
+                c = c1 - '0';
+            else if( c1 >= 'a' && c1 <= 'f' )
+                c = c1 - 'a' + 10;
+            else if( c1 >= 'A' && c1 <= 'F' )
+                c = c1 - 'A' + 10;
+            else {
+                mpi_clear(val);
+                return 1;
+            }
+            c <<= 4;
+            if( c2 >= '0' && c2 <= '9' )
+                c |= c2 - '0';
+            else if( c2 >= 'a' && c2 <= 'f' )
+                c |= c2 - 'a' + 10;
+            else if( c2 >= 'A' && c2 <= 'F' )
+                c |= c2 - 'A' + 10;
+            else {
+                mpi_clear(val);
+                return 1;
+            }
+            a <<= 8;
+            a |= c;
+        }
+        i = 0;
+        val->d[j-1] = a;
+    }
+
+    return 0;
+}
+
+
+/* Dump the value of A in a format suitable for debugging to
+   Libgcrypt's logging stream.  Note that one leading space but no
+   trailing space or linefeed will be printed.  It is okay to pass
+   NULL for A. */
+void 
+gcry_mpi_dump (const gcry_mpi_t a)
+{
+  int i;
+
+  log_printf (" ");
+  if (!a)
+    log_printf ("[MPI_NULL]");
+  else 
+    {
+      if (a->sign)
+        log_printf ( "-");
+#if BYTES_PER_MPI_LIMB == 2
+# define X "4"
+#elif BYTES_PER_MPI_LIMB == 4
+# define X "8"
+#elif BYTES_PER_MPI_LIMB == 8
+# define X "16"
+#elif BYTES_PER_MPI_LIMB == 16
+# define X "32"
+#else
+# error please define the format here
+#endif
+      for (i=a->nlimbs; i > 0 ; i-- )
+        {
+          log_printf (i != a->nlimbs? "%0" X "lX":"%lX", (ulong)a->d[i-1]);
+        }
+#undef X
+      if (!a->nlimbs)
+        log_printf ("0");
+    }
+}
+
+/* Convience function used internally. */
+void
+_gcry_log_mpidump (const char *text, gcry_mpi_t a)
+{
+  log_printf ("%s:", text);
+  gcry_mpi_dump (a);
+  log_printf ("\n");
+}
+
+
+/****************
+ * Return an m_alloced buffer with the MPI (msb first).
+ * NBYTES receives the length of this buffer. Caller must free the
+ * return string (This function does return a 0 byte buffer with NBYTES
+ * set to zero if the value of A is zero. If sign is not NULL, it will
+ * be set to the sign of the A.
+ */
+static byte *
+do_get_buffer( gcry_mpi_t a, unsigned *nbytes, int *sign, int force_secure )
+{
+    byte *p, *buffer;
+    mpi_limb_t alimb;
+    int i;
+    size_t n;
+
+    if( sign )
+        *sign = a->sign;
+    *nbytes = a->nlimbs * BYTES_PER_MPI_LIMB;
+    n = *nbytes? *nbytes:1; /* allocate at least one byte */
+    p = buffer = force_secure || mpi_is_secure(a) ? gcry_xmalloc_secure(n)
+                                                  : gcry_xmalloc(n);
+
+    for(i=a->nlimbs-1; i >= 0; i-- ) {
+        alimb = a->d[i];
+#if BYTES_PER_MPI_LIMB == 4
+        *p++ = alimb >> 24;
+        *p++ = alimb >> 16;
+        *p++ = alimb >>  8;
+        *p++ = alimb      ;
+#elif BYTES_PER_MPI_LIMB == 8
+        *p++ = alimb >> 56;
+        *p++ = alimb >> 48;
+        *p++ = alimb >> 40;
+        *p++ = alimb >> 32;
+        *p++ = alimb >> 24;
+        *p++ = alimb >> 16;
+        *p++ = alimb >>  8;
+        *p++ = alimb      ;
+#else
+        #error please implement for this limb size.
+#endif
+    }
+
+    /* this is sub-optimal but we need to do the shift oepration because
+     * the caller has to free the returned buffer */
+    for(p=buffer; !*p && *nbytes; p++, --*nbytes )
+        ;
+    if( p != buffer )
+        memmove(buffer,p, *nbytes);
+    return buffer;
+}
+
+
+byte *
+_gcry_mpi_get_buffer( gcry_mpi_t a, unsigned *nbytes, int *sign )
+{
+    return do_get_buffer( a, nbytes, sign, 0 );
+}
+
+byte *
+_gcry_mpi_get_secure_buffer( gcry_mpi_t a, unsigned *nbytes, int *sign )
+{
+    return do_get_buffer( a, nbytes, sign, 1 );
+}
+
+/****************
+ * Use BUFFER to update MPI.
+ */
+void
+_gcry_mpi_set_buffer( gcry_mpi_t a, const byte *buffer, unsigned nbytes, int sign )
+{
+    const byte *p;
+    mpi_limb_t alimb;
+    int nlimbs;
+    int i;
+
+    nlimbs = (nbytes + BYTES_PER_MPI_LIMB - 1) / BYTES_PER_MPI_LIMB;
+    RESIZE_IF_NEEDED(a, nlimbs);
+    a->sign = sign;
+
+    for(i=0, p = buffer+nbytes-1; p >= buffer+BYTES_PER_MPI_LIMB; ) {
+#if BYTES_PER_MPI_LIMB == 4
+        alimb  = *p--       ;
+        alimb |= *p-- <<  8 ;
+        alimb |= *p-- << 16 ;
+        alimb |= *p-- << 24 ;
+#elif BYTES_PER_MPI_LIMB == 8
+        alimb  = (mpi_limb_t)*p--       ;
+        alimb |= (mpi_limb_t)*p-- <<  8 ;
+        alimb |= (mpi_limb_t)*p-- << 16 ;
+        alimb |= (mpi_limb_t)*p-- << 24 ;
+        alimb |= (mpi_limb_t)*p-- << 32 ;
+        alimb |= (mpi_limb_t)*p-- << 40 ;
+        alimb |= (mpi_limb_t)*p-- << 48 ;
+        alimb |= (mpi_limb_t)*p-- << 56 ;
+#else
+        #error please implement for this limb size.
+#endif
+        a->d[i++] = alimb;
+    }
+    if( p >= buffer ) {
+#if BYTES_PER_MPI_LIMB == 4
+        alimb  = *p--       ;
+        if( p >= buffer ) alimb |= *p-- <<  8 ;
+        if( p >= buffer ) alimb |= *p-- << 16 ;
+        if( p >= buffer ) alimb |= *p-- << 24 ;
+#elif BYTES_PER_MPI_LIMB == 8
+        alimb  = (mpi_limb_t)*p-- ;
+        if( p >= buffer ) alimb |= (mpi_limb_t)*p-- <<  8 ;
+        if( p >= buffer ) alimb |= (mpi_limb_t)*p-- << 16 ;
+        if( p >= buffer ) alimb |= (mpi_limb_t)*p-- << 24 ;
+        if( p >= buffer ) alimb |= (mpi_limb_t)*p-- << 32 ;
+        if( p >= buffer ) alimb |= (mpi_limb_t)*p-- << 40 ;
+        if( p >= buffer ) alimb |= (mpi_limb_t)*p-- << 48 ;
+        if( p >= buffer ) alimb |= (mpi_limb_t)*p-- << 56 ;
+#else
+        #error please implement for this limb size.
+#endif
+        a->d[i++] = alimb;
+    }
+    a->nlimbs = i;
+    assert( i == nlimbs );
+}
+
+
+
+/* Convert the external representation of an integer stored in BUFFER
+   with a length of BUFLEN into a newly create MPI returned in
+   RET_MPI.  If NBYTES is not NULL, it will receive the number of
+   bytes actually scanned after a successful operation. */
+gcry_error_t
+gcry_mpi_scan( struct gcry_mpi **ret_mpi, enum gcry_mpi_format format,
+               const void *buffer_arg, size_t buflen, size_t *nscanned )
+{
+    const unsigned char *buffer = (const unsigned char*)buffer_arg;
+    struct gcry_mpi *a = NULL;
+    unsigned int len;
+    int secure = (buffer && gcry_is_secure (buffer));
+
+    if (format == GCRYMPI_FMT_SSH)
+      len = 0;
+    else
+      len = buflen;
+
+    if( format == GCRYMPI_FMT_STD ) {
+        const byte *s = buffer;
+
+        a = secure? mpi_alloc_secure ((len+BYTES_PER_MPI_LIMB-1)
+                                      /BYTES_PER_MPI_LIMB)
+                  : mpi_alloc ((len+BYTES_PER_MPI_LIMB-1)/BYTES_PER_MPI_LIMB);
+        if( len ) { /* not zero */
+            a->sign = *s & 0x80;
+            if( a->sign ) {
+                /* FIXME: we have to convert from 2compl to magnitude format */
+                mpi_free(a);
+                return gcry_error (GPG_ERR_INTERNAL);
+            }
+            else
+                _gcry_mpi_set_buffer( a, s, len, 0 );
+        }
+        if( ret_mpi ) {
+            mpi_normalize ( a );
+            *ret_mpi = a;
+        }
+        else
+            mpi_free(a);
+        return gcry_error (GPG_ERR_NO_ERROR);
+    }
+    else if( format == GCRYMPI_FMT_USG ) {
+        a = secure? mpi_alloc_secure ((len+BYTES_PER_MPI_LIMB-1)
+                                      /BYTES_PER_MPI_LIMB)
+                  : mpi_alloc ((len+BYTES_PER_MPI_LIMB-1)/BYTES_PER_MPI_LIMB);
+
+        if( len )  /* not zero */
+            _gcry_mpi_set_buffer( a, buffer, len, 0 );
+        if( ret_mpi ) {
+            mpi_normalize ( a );
+            *ret_mpi = a;
+        }
+        else
+            mpi_free(a);
+        return gcry_error (GPG_ERR_NO_ERROR);
+    }
+    else if( format == GCRYMPI_FMT_PGP ) {
+        a = mpi_read_from_buffer (buffer, &len, secure);
+        if( nscanned )
+            *nscanned = len;
+        if( ret_mpi && a ) {
+            mpi_normalize ( a );
+            *ret_mpi = a;
+        }
+        else
+            mpi_free(a);
+        return gcry_error (a ? GPG_ERR_NO_ERROR : GPG_ERR_INV_OBJ);
+    }
+    else if( format == GCRYMPI_FMT_SSH ) {
+        const unsigned char *s = buffer;
+        size_t n;
+
+        if( len && len < 4 )
+            return gcry_error (GPG_ERR_TOO_SHORT);
+        n = s[0] << 24 | s[1] << 16 | s[2] << 8 | s[3];
+        s += 4; 
+        if (len)
+          len -= 4;
+        if( len && n > len )
+            return gcry_error (GPG_ERR_TOO_LARGE); /* or should it be
+                                                      too_short */
+
+        a = secure? mpi_alloc_secure ((n+BYTES_PER_MPI_LIMB-1)
+                                      /BYTES_PER_MPI_LIMB)
+                  : mpi_alloc ((n+BYTES_PER_MPI_LIMB-1)/BYTES_PER_MPI_LIMB);
+        if( n ) { /* not zero */
+            a->sign = *s & 0x80;
+            if( a->sign ) {
+                /* FIXME: we have to convert from 2compl to magnitude format */
+                mpi_free(a);
+                return gcry_error (GPG_ERR_INTERNAL);
+            }
+            else
+                _gcry_mpi_set_buffer( a, s, n, 0 );
+        }
+        if( nscanned )
+            *nscanned = n+4;
+        if( ret_mpi ) {
+            mpi_normalize ( a );
+            *ret_mpi = a;
+        }
+        else
+            mpi_free(a);
+        return gcry_error (GPG_ERR_NO_ERROR);
+    }
+    else if( format == GCRYMPI_FMT_HEX ) {
+        if( buflen )
+            return gcry_error (GPG_ERR_INV_ARG); /* can only handle C
+                                                    strings for now */
+        a = secure? mpi_alloc_secure (0) : mpi_alloc(0);
+        if( mpi_fromstr ( a, (const char *)buffer ) )
+            return gcry_error (GPG_ERR_INV_OBJ);
+        if( ret_mpi ) {
+            mpi_normalize ( a );
+            *ret_mpi = a;
+        }
+        else
+            mpi_free(a);
+        return gcry_error (GPG_ERR_NO_ERROR);
+    }
+    else
+        return gcry_error (GPG_ERR_INV_ARG);
+}
+
+/* Convert the big integer A into the external representation
+   described by FORMAT and store it in the provided BUFFER which has
+   been allocated by the user with a size of BUFLEN bytes.  NWRITTEN
+   receives the actual length of the external representation unless it
+   has been passed as NULL.  BUFFER may be NULL to query the required
+   length.*/
+gcry_error_t
+gcry_mpi_print( enum gcry_mpi_format format,
+                unsigned char *buffer, size_t buflen,
+                size_t *nwritten, struct gcry_mpi *a)
+{
+    unsigned int nbits = mpi_get_nbits(a);
+    size_t len;
+    size_t dummy_nwritten;
+
+    if (!nwritten)
+      nwritten = &dummy_nwritten;
+
+    len = buflen;
+    *nwritten = 0;
+    if( format == GCRYMPI_FMT_STD ) {
+        unsigned char *tmp;
+        int extra = 0;
+        unsigned int n;
+
+        if( a->sign )
+            return gcry_error (GPG_ERR_INTERNAL); /* can't handle it yet */
+
+        tmp = _gcry_mpi_get_buffer( a, &n, NULL );
+        if( n && (*tmp & 0x80) ) {
+            n++;
+            extra=1;
+        }
+
+        if (buffer && n > len) {
+            /* The provided buffer is too short. */
+            gcry_free(tmp);
+            return gcry_error (GPG_ERR_TOO_SHORT);  
+        }
+        if( buffer ) {
+            byte *s = buffer;
+            if( extra )
+                *s++ = 0;
+
+            memcpy( s, tmp, n-extra );
+        }
+        gcry_free(tmp);
+        *nwritten = n;
+        return gcry_error (GPG_ERR_NO_ERROR);
+    }
+    else if( format == GCRYMPI_FMT_USG ) {
+        unsigned int n = (nbits + 7)/8;
+
+        /* we ignore the sign for this format */
+        /* FIXME: for performance reasons we should put this into
+         * mpi_aprint becuase we can then use the buffer directly */
+        if (buffer && n > len)
+            return gcry_error (GPG_ERR_TOO_SHORT);  /* the provided buffer is too short */
+        if( buffer ) {
+            unsigned char *tmp;
+            tmp = _gcry_mpi_get_buffer( a, &n, NULL );
+            memcpy( buffer, tmp, n );
+            gcry_free(tmp);
+        }
+        *nwritten = n;
+        return gcry_error (GPG_ERR_NO_ERROR);
+    }
+    else if( format == GCRYMPI_FMT_PGP ) {
+        unsigned int n = (nbits + 7)/8;
+
+        if( a->sign )
+            return gcry_error (GPG_ERR_INV_ARG); /* pgp format can only handle unsigned */
+
+        if (buffer && n+2 > len)
+            return gcry_error (GPG_ERR_TOO_SHORT);  /* the provided buffer is too short */
+        if( buffer ) {
+            unsigned char *tmp;
+            unsigned char *s = buffer;
+            s[0] = nbits >> 8;
+            s[1] = nbits;
+
+            tmp = _gcry_mpi_get_buffer( a, &n, NULL );
+            memcpy( s+2, tmp, n );
+            gcry_free(tmp);
+        }
+        *nwritten = n+2;
+        return gcry_error (GPG_ERR_NO_ERROR);
+    }
+    else if( format == GCRYMPI_FMT_SSH ) {
+        unsigned char *tmp;
+        int extra = 0;
+        unsigned int n;
+
+        if( a->sign )
+            return gcry_error (GPG_ERR_INTERNAL); /* can't handle it yet */
+
+        tmp = _gcry_mpi_get_buffer( a, &n, NULL );
+        if( n && (*tmp & 0x80) ) {
+            n++;
+            extra=1;
+        }
+
+        if (buffer && n+4 > len) {
+            gcry_free(tmp);
+            return gcry_error (GPG_ERR_TOO_SHORT);  /* the provided buffer is too short */
+        }
+        if( buffer ) {
+            byte *s = buffer;
+            *s++ = n >> 24;
+            *s++ = n >> 16;
+            *s++ = n >> 8;
+            *s++ = n;
+            if( extra )
+                *s++ = 0;
+
+            memcpy( s, tmp, n-extra );
+        }
+        gcry_free(tmp);
+        *nwritten = 4+n;
+        return gcry_error (GPG_ERR_NO_ERROR);
+    }
+    else if( format == GCRYMPI_FMT_HEX ) {
+        byte *tmp;
+        int i;
+        int extra = 0;
+        unsigned int n=0;
+
+        tmp = _gcry_mpi_get_buffer( a, &n, NULL );
+        if( !n || (*tmp & 0x80) )
+            extra=2;
+
+        if(buffer && 2*n + extra + !!a->sign + 1 > len) {
+            gcry_free(tmp);
+            return gcry_error (GPG_ERR_TOO_SHORT);  /* the provided buffer is too short */
+        }
+        if( buffer ) {
+            byte *s = buffer;
+            if( a->sign )
+                *s++ = '-';
+            if( extra ) {
+                *s++ = '0';
+                *s++ = '0';
+            }
+
+            for(i=0; i < n; i++ ) {
+                unsigned int c = tmp[i];
+                *s++ = (c >> 4) < 10? '0'+(c>>4) : 'A'+(c>>4)-10 ;
+                c &= 15;
+                *s++ = c < 10? '0'+c : 'A'+c-10 ;
+            }
+            *s++ = 0;
+            *nwritten = s - buffer;
+        }
+        else {
+            *nwritten = 2*n + extra + !!a->sign + 1;
+        }
+        gcry_free(tmp);
+        return gcry_error (GPG_ERR_NO_ERROR);
+    }
+    else
+        return gcry_error (GPG_ERR_INV_ARG);
+}
+
+/****************
+ * Like gcry_mpi_print but this function allocates the buffer itself.
+ * The caller has to supply the address of a pointer. NWRITTEN may be
+ * NULL.
+ */
+gcry_error_t
+gcry_mpi_aprint( enum gcry_mpi_format format,
+                 unsigned char **buffer, size_t *nwritten,
+                 struct gcry_mpi *a )
+{
+    size_t n;
+    gcry_error_t rc;
+
+    *buffer = NULL;
+    rc = gcry_mpi_print( format, NULL, 0, &n, a );
+    if( rc )
+        return rc;
+    *buffer = mpi_is_secure(a) ? gcry_xmalloc_secure( n ) : gcry_xmalloc( n );
+    rc = gcry_mpi_print( format, *buffer, n, &n, a );
+    if( rc ) {
+        gcry_free(*buffer);
+        *buffer = NULL;
+    }
+    else if( nwritten )
+        *nwritten = n;
+    return rc;
+}
+