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limit number of PNG chunks

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reduces the threat of PNG decompression bombs
This commit is contained in:
John Cupitt 2021-08-06 10:55:08 +01:00
parent 5263686511
commit fd1a036cd8
1 changed files with 11 additions and 1 deletions
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12
libvips/foreign/vipspng.c
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@ -310,11 +310,21 @@ read_new( VipsSource *source, VipsImage *out, gboolean fail )
if( !(read->pInfo = png_create_info_struct( read->pPng )) )
return( NULL );
#ifdef HAVE_PNG_SET_CHUNK_MALLOC_MAX
/* By default, libpng refuses to open files with a metadata chunk
* larger than 8mb. We've seen real files with 20mb, so set 50mb.
*/
#ifdef HAVE_PNG_SET_CHUNK_MALLOC_MAX
png_set_chunk_malloc_max( read->pPng, 50 * 1024 * 1024 );
/* This limits the number of chunks. The limit from
* png_set_chunk_malloc_max() times this value is the maximum
* memory use.
*
* libnpng defaults to 1000, which is rather high.
*/
png_set_chunk_cache_max( read->pPng, 100 );
#endif /*HAVE_PNG_SET_CHUNK_MALLOC_MAX*/
png_read_info( read->pPng, read->pInfo );