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84 lines
3.0 KiB
ReStructuredText
84 lines
3.0 KiB
ReStructuredText
3.1.1
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-----
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Security
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========
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:cve:`2016-0740`: Buffer overflow in ``TiffDecode.c``
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^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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Pillow 3.1.0 and earlier when linked against libtiff >= 4.0.0 on x64
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may overflow a buffer when reading a specially crafted tiff file.
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Specifically, libtiff >= 4.0.0 changed the return type of
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``TIFFScanlineSize`` from ``int32`` to machine dependent
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``int32|64``. If the scanline is sized so that it overflows an
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``int32``, it may be interpreted as a negative number, which will then
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pass the size check in ``TiffDecode.c`` line 236. To do this, the
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logical scanline size has to be > 2gb, and for the test file, the
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allocated buffer size is 64k against a roughly 4gb scan line size. Any
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image data over 64k is written over the heap, causing a segfault.
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This issue was found by security researcher FourOne.
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:cve:`2016-0775`: Buffer overflow in ``FliDecode.c``
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^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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In all versions of Pillow, dating back at least to the last PIL 1.1.7
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release, FliDecode.c has a buffer overflow error (:cve:`2016-0775`).
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Around line 192:
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.. code-block:: c
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case 16:
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/* COPY chunk */
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for (y = 0; y < state->ysize; y++) {
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UINT8* buf = (UINT8*) im->image[y];
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memcpy(buf+x, data, state->xsize);
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data += state->xsize;
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}
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break;
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The memcpy has error where ``x`` is added to the target buffer
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address. ``X`` is used in several internal temporary variable roles,
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but can take a value up to the width of the image. ``Im->image[y]``
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is a set of row pointers to segments of memory that are the size of
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the row. At the max ``y``, this will write the contents of the line
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off the end of the memory buffer, causing a segfault.
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This issue was found by Alyssa Besseling at Atlassian.
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:cve:`2016-2533`: Buffer overflow in ``PcdDecode.c``
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^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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In all versions of Pillow, dating back at least to the last PIL 1.1.7
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release, ``PcdDecode.c`` has a buffer overflow error (:cve:`2016-2533`).
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The ``state.buffer`` for ``PcdDecode.c`` is allocated based on a 3
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bytes per pixel sizing, where ``PcdDecode.c`` wrote into the buffer
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assuming 4 bytes per pixel. This writes 768 bytes beyond the end of
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the buffer into other Python object storage. In some cases, this
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causes a segfault, in others an internal Python malloc error.
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Integer overflow in ``Resample.c``
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^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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If a large value was passed into the new size for an image, it is
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possible to overflow an ``int32`` value passed into malloc.
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.. code-block:: c
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kk = malloc(xsize * kmax * sizeof(float));
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...
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xbounds = malloc(xsize * 2 * sizeof(int));
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``xsize`` is trusted user input. These multiplications can overflow,
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leading the ``malloc``'d buffer to be undersized. These allocations are
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followed by a loop that writes out of bounds. This can lead to
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corruption on the heap of the Python process with attacker controlled
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float data.
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This issue was found by Ned Williamson.
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