diff options
Diffstat (limited to 'g10/misc.c')
| -rw-r--r-- | g10/misc.c | 180 |
1 files changed, 135 insertions, 45 deletions
diff --git a/g10/misc.c b/g10/misc.c index 7e8e85a9e..4d7644f4c 100644 --- a/g10/misc.c +++ b/g10/misc.c @@ -34,10 +34,13 @@ #include <gcrypt.h> #include "util.h" #include "main.h" +#include "memory.h" #include "options.h" #include "i18n.h" +#define MAX_EXTERN_MPI_BITS 16384 + #if defined(__linux__) && defined(__alpha__) && __GLIBC__ < 2 #warning using trap_unaligned @@ -86,23 +89,140 @@ disable_core_dumps() -u16 -checksum_u16( unsigned n ) +/**************** + * write an mpi to out. + */ +int +mpi_write( IOBUF out, MPI a ) { - u16 a; + char buffer[(MAX_EXTERN_MPI_BITS+7)/8]; + size_t nbytes; + int rc; - a = (n >> 8) & 0xff; - if( opt.emulate_bugs & EMUBUG_GPGCHKSUM ) { - a |= n & 0xff; - log_debug("csum_u16 emulated for n=%u\n", n); + nbytes = (MAX_EXTERN_MPI_BITS+7)/8; + rc = gcry_mpi_print( GCRYMPI_FMT_PGP, buffer, &nbytes, a ); + if( !rc ) + rc = iobuf_write( out, buffer, nbytes ); + + return rc; +} + +/**************** + * Writye a MPI to out, but in this case it is an opaque one, + * s used vor v3 protected keys. + */ +int +mpi_write_opaque( IOBUF out, MPI a ) +{ + size_t nbytes, nbits; + int rc; + + assert( gcry_mpi_get_flag( a, GCRYMPI_FLAG_OPAQUE ) ); + p = gcry_mpi_get_opaque( a, &nbits ); + nbytes = (nbits+7) / 8; + iobuf_put( out, nbits >> 8 ); + iobuf_put( out, nbits ) + rc = iobuf_write( out, p, nbytes ); + return rc; +} + + +/**************** + * Read an external representation of an mpi and return the MPI + * The external format is a 16 bit unsigned value stored in network byte order, + * giving the number of bits for the following integer. The integer is stored + * with MSB first (left padded with zeroes to align on a byte boundary). + */ +MPI +mpi_read(IOBUF inp, unsigned *ret_nread, int secure) +{ + int c, c1, c2, i; + unsigned nbits, nbytes, nread=0; + MPI a = NULL; + byte *buf = NULL; + byte *p; + + if( (c = c1 = iobuf_get(inp)) == -1 ) + goto leave; + nbits = c << 8; + if( (c = c2 = iobuf_get(inp)) == -1 ) + goto leave; + nbits |= c; + if( nbits > MAX_EXTERN_MPI_BITS ) { + log_error("mpi too large (%u bits)\n", nbits); + goto leave; + } + nread = 2; + nbytes = (nbits+7) / 8; + buf = secure? m_alloc_secure( nbytes+2 ) : m_alloc( nbytes+2 ); + p = buf; + p[0] = c1; + p[1] = c2; + for( i=0 ; i < nbytes; i++ ) { + p[i+2] = iobuf_get(inp) & 0xff; + nread++; + } + nread += nbytes; + /* FIXME: replace with the gcry_scan function */ + a = mpi_read_from_buffer( buf, &nread, secure ); + + leave: + m_free(buf); + if( nread > *ret_nread ) + log_bug("mpi larger than packet"); + else + *ret_nread = nread; + return a; +} + +/**************** + * Same as mpi_read but the value is stored as an opaque MPI. + * This function is used to read encrpted MPI of v3 packets. + */ +GCRY_MPI +mpi_read_opaque(IOBUF inp, unsigned *ret_nread ) +{ + int c, c1, c2, i; + unsigned nbits, nbytes, nread=0; + GCRY_MPI a = NULL; + byte *buf = NULL; + byte *p; + + if( (c = c1 = iobuf_get(inp)) == -1 ) + goto leave; + nbits = c << 8; + if( (c = c2 = iobuf_get(inp)) == -1 ) + goto leave; + nbits |= c; + if( nbits > MAX_EXTERN_MPI_BITS ) { + log_error("mpi too large (%u bits)\n", nbits); + goto leave; } + nread = 2; + nbytes = (nbits+7) / 8; + buf = m_alloc( nbytes ); + p = buf; + for( i=0 ; i < nbytes; i++ ) { + p[i] = iobuf_get(inp) & 0xff; + nread++; + } + nread += nbytes; + a = gcry_mpi_set_opaque(NULL, buf, nbits ); + buf = NULL; + + leave: + m_free(buf); + if( nread > *ret_nread ) + log_bug("mpi larger than packet"); else - a += n & 0xff; + *ret_nread = nread; return a; } -static u16 -checksum_u16_nobug( unsigned n ) + + +u16 +checksum_u16( unsigned n ) { u16 a; @@ -130,43 +250,13 @@ checksum_mpi( MPI a ) unsigned nbits; buffer = mpi_get_buffer( a, &nbytes, NULL ); - /* some versions of gpg encode wrong values for the length of an mpi - * so that mpi_get_nbits() which counts the mpi yields another (shorter) - * value than the one store with the mpi. mpi_get_nbit_info() returns - * this stored value if it is still available. - */ - - if( opt.emulate_bugs & EMUBUG_GPGCHKSUM ) - nbits = 0; - else - nbits = mpi_get_nbit_info(a); - if( !nbits ) - nbits = mpi_get_nbits(a); + nbits = mpi_get_nbits(a); csum = checksum_u16( nbits ); csum += checksum( buffer, nbytes ); m_free( buffer ); return csum; } -/**************** - * This is the correct function - */ -u16 -checksum_mpi_counted_nbits( MPI a ) -{ - u16 csum; - byte *buffer; - unsigned nbytes; - unsigned nbits; - - buffer = mpi_get_buffer( a, &nbytes, NULL ); - nbits = mpi_get_nbits(a); - mpi_set_nbit_info(a,nbits); - csum = checksum_u16_nobug( nbits ); - csum += checksum( buffer, nbytes ); - m_free( buffer ); - return csum; -} u32 @@ -213,10 +303,10 @@ print_cipher_algo_note( int algo ) { if( algo >= 100 && algo <= 110 ) no_exp_algo(); - else if( algo == CIPHER_ALGO_3DES - || algo == CIPHER_ALGO_CAST5 - || algo == CIPHER_ALGO_BLOWFISH - || algo == CIPHER_ALGO_TWOFISH + else if( algo == GCRY_CIPHER_3DES + || algo == GCRY_CIPHER_CAST5 + || algo == GCRY_CIPHER_BLOWFISH + || algo == GCRY_CIPHER_TWOFISH ) ; else { |