Diffstat (limited to 'pwmanager/libcrypt/mpi/mpicoder.c') (more/less context) (show whitespace changes)
| -rw-r--r-- | pwmanager/libcrypt/mpi/mpicoder.c | 643 |
1 files changed, 643 insertions, 0 deletions
diff --git a/pwmanager/libcrypt/mpi/mpicoder.c b/pwmanager/libcrypt/mpi/mpicoder.c new file mode 100644 index 0000000..d501fe4 --- a/dev/null +++ b/pwmanager/libcrypt/mpi/mpicoder.c @@ -0,0 +1,643 @@ +/* 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(byte *buffer, unsigned *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 unsigned char *buffer, size_t buflen, size_t *nscanned ) +{ + 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( (char*)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 byte *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, 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 ) { + 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) { + gcry_free(tmp); + return gcry_error (GPG_ERR_TOO_SHORT); /* the provided buffer is 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 ) { + 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 ) { + char *tmp; + byte *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 ) { + 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; +} + |