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tif_jpeg.c: revise logic to detect potential excessive memory usage when decoding multiscan JPEG compressed images

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This commit is contained in:
Even Rouault 2020-04-24 20:29:06 +02:00
parent 1b4708f67f
commit daed3c04ab
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GPG Key ID: 33EBBFC47B3DD87D
1 changed files with 24 additions and 25 deletions
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39
libtiff/tif_jpeg.c
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@ -1206,35 +1206,34 @@ JPEGPreDecode(TIFF* tif, uint16 s)
/* store for all coefficients */
/* See call to jinit_d_coef_controller() from master_selection() */
/* in libjpeg */
toff_t nRequiredMemory = (toff_t)sp->cinfo.d.image_width *
sp->cinfo.d.image_height *
sp->cinfo.d.num_components *
((td->td_bitspersample+7)/8);
/* BLOCK_SMOOTHING_SUPPORTED is generally defined, so we need */
/* to replicate the logic of jinit_d_coef_controller() */
if( sp->cinfo.d.progressive_mode )
nRequiredMemory *= 3;
#ifndef TIFF_LIBJPEG_LARGEST_MEM_ALLOC
#define TIFF_LIBJPEG_LARGEST_MEM_ALLOC (100 * 1024 * 1024)
#endif
/* 1 MB for regular libjpeg usage */
toff_t nRequiredMemory = 1024 * 1024;
if( nRequiredMemory > TIFF_LIBJPEG_LARGEST_MEM_ALLOC &&
for (ci = 0; ci < sp->cinfo.d.num_components; ci++) {
const jpeg_component_info *compptr = &(sp->cinfo.d.comp_info[ci]);
nRequiredMemory += (toff_t)(
((compptr->width_in_blocks + compptr->h_samp_factor - 1) / compptr->h_samp_factor)) *
((compptr->height_in_blocks + compptr->v_samp_factor - 1) / compptr->v_samp_factor) *
sizeof(JBLOCK);
}
if( sp->cinfo.d.mem->max_memory_to_use > 0 &&
nRequiredMemory > (toff_t)(sp->cinfo.d.mem->max_memory_to_use) &&
getenv("LIBTIFF_ALLOW_LARGE_LIBJPEG_MEM_ALLOC") == NULL )
{
TIFFErrorExt(tif->tif_clientdata, module,
"Reading this strip would require libjpeg to allocate "
"Reading this image would require libjpeg to allocate "
"at least %u bytes. "
"This is disabled since above the %u threshold. "
"You may override this restriction by defining the "
"LIBTIFF_ALLOW_LARGE_LIBJPEG_MEM_ALLOC environment variable, "
"or recompile libtiff by defining the "
"TIFF_LIBJPEG_LARGEST_MEM_ALLOC macro to a value greater "
"than %u",
(unsigned)nRequiredMemory,
(unsigned)TIFF_LIBJPEG_LARGEST_MEM_ALLOC,
(unsigned)TIFF_LIBJPEG_LARGEST_MEM_ALLOC);
return (0);
"or setting the JPEGMEM environment variable to a value greater "
"or equal to '%uM'",
(unsigned)(nRequiredMemory),
(unsigned)(sp->cinfo.d.mem->max_memory_to_use),
(unsigned)((nRequiredMemory + 1000000 - 1) / 1000000));
return 0;
}
}