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41 lines
1.3 KiB
ReStructuredText
41 lines
1.3 KiB
ReStructuredText
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3.3.2
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=====
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Integer overflow in Map.c
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-------------------------
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Pillow prior to 3.3.2 may experience integer overflow errors in map.c
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when reading specially crafted image files. This may lead to memory
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disclosure or corruption.
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Specifically, when parameters from the image are passed into
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``Image.core.map_buffer``, the size of the image was calculated with
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``xsize`` * ``ysize`` * ``bytes_per_pixel``. This will overflow if the
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result is larger than SIZE_MAX. This is possible on a 32-bit system.
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Furthermore this ``size`` value was added to a potentially attacker
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provided ``offset`` value and compared to the size of the buffer
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without checking for overflow or negative values.
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These values were then used for creating pointers, at which point
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Pillow could read the memory and include it in other images. The image
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was marked readonly, so Pillow would not ordinarily write to that
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memory without duplicating the image first.
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This issue was found by Cris Neckar at Divergent Security.
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Sign Extension in Storage.c
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---------------------------
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Pillow prior to 3.3.2 and PIL 1.1.7 (at least) do not check for
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negative image sizes in ``ImagingNew`` in ``Storage.c``. A negative
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image size can lead to a smaller allocation than expected, leading to
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arbitrary writes.
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This issue was found by Cris Neckar at Divergent Security.
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