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sanity-check PNG read line size

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This commit is contained in:
John Cupitt 2012-03-15 12:53:38 +00:00
parent 8126d48717
commit 2e7f4b2900
2 changed files with 21 additions and 22 deletions
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2
ChangeLog
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@ -1,4 +1,6 @@
13/3/12 started 7.28.2 13/3/12 started 7.28.2
- better PNG alpha handling
- sanity-check PNG read geometry
13/3/12 started 7.28.1 13/3/12 started 7.28.1
- add ICC profile read/write for png files - add ICC profile read/write for png files

41
libvips/foreign/vipspng.c
View File

@ -40,6 +40,9 @@
* - add a longjmp() to our error handler to stop the default one running * - add a longjmp() to our error handler to stop the default one running
* 13/3/12 * 13/3/12
* - add ICC profile read/write * - add ICC profile read/write
* 15/3/12
* - better alpha handling
* - sanity check pixel geometry before allowing read
*/ */
/* /*
@ -213,32 +216,22 @@ png2vips_header( Read *read, VipsImage *out )
/* png_get_channels() gives us 1 band for palette images ... so look /* png_get_channels() gives us 1 band for palette images ... so look
* at colour_type for output bands. * at colour_type for output bands.
*
* Ignore alpha, we detect that separately below.
*/ */
switch( color_type ) { switch( color_type ) {
case PNG_COLOR_TYPE_PALETTE: case PNG_COLOR_TYPE_PALETTE:
bands = 3; bands = 3;
/* If there's transparency in the palette, we make an alpha.
*/
if( png_get_valid( read->pPng, read->pInfo, PNG_INFO_tRNS ) )
bands = 4;
break; break;
case PNG_COLOR_TYPE_GRAY_ALPHA:
case PNG_COLOR_TYPE_GRAY: case PNG_COLOR_TYPE_GRAY:
bands = 1; bands = 1;
break; break;
case PNG_COLOR_TYPE_GRAY_ALPHA:
bands = 2;
break;
case PNG_COLOR_TYPE_RGB: case PNG_COLOR_TYPE_RGB:
bands = 3;
break;
case PNG_COLOR_TYPE_RGB_ALPHA: case PNG_COLOR_TYPE_RGB_ALPHA:
bands = 4; bands = 3;
break; break;
default: default:
@ -264,17 +257,11 @@ png2vips_header( Read *read, VipsImage *out )
if( color_type == PNG_COLOR_TYPE_PALETTE ) if( color_type == PNG_COLOR_TYPE_PALETTE )
png_set_palette_to_rgb( read->pPng ); png_set_palette_to_rgb( read->pPng );
/* Expand transparency images too. /* Expand transparency.
*/ */
if( png_get_valid( read->pPng, read->pInfo, PNG_INFO_tRNS ) ) { if( png_get_valid( read->pPng, read->pInfo, PNG_INFO_tRNS ) ) {
png_set_tRNS_to_alpha( read->pPng ); png_set_tRNS_to_alpha( read->pPng );
bands += 1;
/* Some PNGs have an alpha but do not set color_type correctly
* .. make sure we add space for an alpha.
*/
if( color_type == PNG_COLOR_TYPE_GRAY ||
color_type == PNG_COLOR_TYPE_RGB )
bands += 1;
} }
/* Expand <8 bit images to full bytes. /* Expand <8 bit images to full bytes.
@ -345,6 +332,16 @@ png2vips_header( Read *read, VipsImage *out )
(VipsCallbackFn) vips_free, profile_copy, proflen ); (VipsCallbackFn) vips_free, profile_copy, proflen );
} }
/* Sanity-check lines sizes.
*/
png_read_update_info( read->pPng, read->pInfo );
if( png_get_rowbytes( read->pPng, read->pInfo ) !=
VIPS_IMAGE_SIZEOF_LINE( out ) ) {
vips_error( "vipspng",
"%s", _( "unable to read PNG header" ) );
return( -1 );
}
return( 0 ); return( 0 );
} }