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improve base64 encode

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- better data source too large check
- could write up to three bytes too far in worst case
- remove dead base64.h
- add an assert for overflow

see https://github.com/libvips/libvips/issues/1263
This commit is contained in:
John Cupitt 2019-03-20 12:50:44 +00:00
parent 16d6e995a3
commit d7f9ad8b41
3 changed files with 11 additions and 33 deletions
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1
libvips/iofuncs/Makefile.am
View File

@ -9,7 +9,6 @@ libiofuncs_la_SOURCES = \
gate.c \
enumtypes.c \
object.c \
base64.h \
base64.c \
error.c \
image.c \

17
libvips/iofuncs/base64.c
View File

@ -67,6 +67,10 @@ Modified on:
31/5/15
- oops siged/unsigned mess-up meant we were not padding correctly
20/3/19
- larger output allocate
- better max size check
*/
/*
@ -84,8 +88,7 @@ Modified on:
#include <assert.h>
#include <vips/vips.h>
#include "base64.h"
#include <vips/internal.h>
static unsigned char b64_list[] =
"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
@ -159,20 +162,20 @@ char *
vips__b64_encode( const unsigned char *data, size_t data_length )
{
/* Worst case: 1.333 chars per byte, plus 10% for extra carriage
* returns and stuff. And the \n\0 at the end.
* returns and stuff, plus the final \n\0.
*/
const size_t output_data_length = data_length * 44 / 30 + 2;
const size_t output_data_length = data_length * 44 / 30 + 10;
char *buffer;
char *p;
int i;
int cursor;
if( output_data_length > 10 * 1024 * 1024 ) {
if( data_length > 10 * 1024 * 1024 ) {
/* We shouldn't really be used for large amounts of data, plus
* we are using int offsets.
*
* A large ICC profile can be 1MB, so allow 10MB of b64.
* A large ICC profile can be 1MB, so allow 10MB.
*/
vips_error( "vips__b64_encode", "%s", _( "too much data" ) );
return( NULL );
@ -202,6 +205,8 @@ vips__b64_encode( const unsigned char *data, size_t data_length )
*p++ = '\n';
*p++ = '\0';
g_assert( (size_t) (p - buffer) < output_data_length );
#ifdef DEBUG
{
unsigned int total;

26
libvips/iofuncs/base64.h
View File

@ -1,26 +0,0 @@
/*
Copyright (C) 1991-2005 The National Gallery
This library 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.
This library 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 library; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301 USA
*/
/* base64 encode/decode functions.
*/
char *im__b64_encode( const unsigned char *data, size_t data_length );
unsigned char *im__b64_decode( const char *buffer, size_t *data_length );