REDHAT-BUG-844101

First published: Sat Jul 28 2012(Updated: )

Tom Lane (tgl) found an issue in ImageMagick. Basically <a href="https://access.redhat.com/security/cve/CVE-2011-3026">CVE-2011-3026</a> deals with libpng memory allocation, limitations have been added so that a bad PNG can't cause the system to allocate a lot of memory causing a denial of service. However on further investigation of ImageMagick Tom Lane found that PNG malloc function (Magick_png_malloc) in turn calls AcquireMagickMemory with an improper size argument: #ifdef PNG_USER_MEM_SUPPORTED static png_voidp Magick_png_malloc(png_structp png_ptr,png_uint_32 size) { (void) png_ptr; return((png_voidp) AcquireMagickMemory((size_t) size)); } This is incorrect, the size argument should be declared png_alloc_size_t according to 1.5, or png_size_t according to 1.2. "As this function stands, it invisibly does the wrong thing for any request over 4GB. On big-endian architectures it very possibly will do the wrong thing even for requests less than that. So the reason why the hard-wired 4GB limit prevents a core dump is that it masks the ABI mismatch here." So basically we have memory allocations problems that can probably lead to a denial of service.

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• collector/redhat-bugzilla
• alias/CVE-2012-3437
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• vendor/imagemagick
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