Infinite loop on corrupted JPEG input.

[adambuchbinder]

Running exifprobe -L hang.jpg leads to an infinite loop. (Without -L, it does the same, but it's harder to read.) The beginning of the output looks like:

FileName = hang.jpg
FileType = JPEG
FileSize = 911
JPEG.APP0           = @2:16       
JPEG.APP0.Version       = 1.1
JPEG.APP0.Units         = 'dots/inch'
JPEG.APP0.Xdensity      = 96
JPEG.APP0.Ydensity      = 96
JPEG.APP0.XThumbnail    = 0
JPEG.APP0.YThumbnail    = 0
JPEG.APP1           = @20:294      
JPEG.APP1.Ifd0.DateTime                    = 'AAAAAAAAAAAAAAAAAAA'
JPEG.APP1.Ifd0.TAG_0x5100                  = 0
JPEG.APP1.Ifd0.TAG_0x5101                  = 1
JPEG.APP1.Ifd0.JPEGInterchangeFormatLength = 00,00,00,ff,ff,ff,ff,ff,ff,00,00,00
JPEG.APP1.Ifd0.TAG_0x5103                  = 0
JPEG.APP1.Ifd0.TAG_0x5104                  = 2
JPEG.APP1.Ifd0.ExifIFDPointer              = @198
JPEG.APP1.Ifd0.PreviewDateTime             = 'CCCC !"#$%&'()*+,-./<=>?@'
JPEG.APP1.Ifd0.Exif.Version                     = '0231'
JPEG.APP1.Ifd0.Exif.DateTimeOriginal            = 'A:.B:.C:.D:.E:.F:.G|'
JPEG.APP1.Ifd0.Exif.DateTimeDigitized           = 'BBBBBBBBBBBBBBBBBBB'
JPEG.APP1.Ifd0.Exif.ComponentsConfiguration     = 1,2,3,0 = 'YCbCr'
JPEG.APP1.Ifd0.Exif.FlashPixVersion             = '0100'
JPEG.APP1.Ifd0.Exif.ColorSpace                  = 65535 = 'uncalibrated'
JPEG.APP1.APP0           = @2:16       
JPEG.APP1.APP0.Version       = 1.1
JPEG.APP1.APP0.Units         = 'dots/inch'
JPEG.APP1.APP0.Xdensity      = 96
JPEG.APP1.APP0.Ydensity      = 96
JPEG.APP1.APP0.XThumbnail    = 0
JPEG.APP1.APP0.YThumbnail    = 0
JPEG.APP1.APP1           = @20:294      
JPEG.APP1.APP1.Ifd0.DateTime                    = 'AAAAAAAAAAAAAAAAAAA'
JPEG.APP1.APP1.Ifd0.TAG_0x5100                  = 0
JPEG.APP1.APP1.Ifd0.TAG_0x5101                  = 1
JPEG.APP1.APP1.Ifd0.JPEGInterchangeFormatLength = 00,00,00,ff,ff,ff,ff,ff,ff,00,00,00
JPEG.APP1.APP1.Ifd0.TAG_0x5103                  = 0
JPEG.APP1.APP1.Ifd0.TAG_0x5104                  = 2
JPEG.APP1.APP1.Ifd0.ExifIFDPointer              = @198
JPEG.APP1.APP1.Ifd0.PreviewDateTime             = 'CCCC !"#$%&'()*+,-./<=>?@'
JPEG.APP1.APP1.Ifd0.Exif.Version                     = '0231'
JPEG.APP1.APP1.Ifd0.Exif.DateTimeOriginal            = 'A:.B:.C:.D:.E:.F:.G|'
JPEG.APP1.APP1.Ifd0.Exif.DateTimeDigitized           = 'BBBBBBBBBBBBBBBBBBB'
JPEG.APP1.APP1.Ifd0.Exif.ComponentsConfiguration     = 1,2,3,0 = 'YCbCr'
JPEG.APP1.APP1.Ifd0.Exif.FlashPixVersion             = '0100'
JPEG.APP1.APP1.Ifd0.Exif.ColorSpace                  = 65535 = 'uncalibrated'
JPEG.APP1.APP1.APP0           = @2:16       
JPEG.APP1.APP1.APP0.Version       = 1.1
JPEG.APP1.APP1.APP0.Units         = 'dots/inch'
JPEG.APP1.APP1.APP0.Xdensity      = 96
JPEG.APP1.APP1.APP0.Ydensity      = 96
JPEG.APP1.APP1.APP0.XThumbnail    = 0
JPEG.APP1.APP1.APP0.YThumbnail    = 0
JPEG.APP1.APP1.APP1           = @20:294      
JPEG.APP1.APP1.APP1.Ifd0.DateTime                    = 'AAAAAAAAAAAAAAAAAAA'

And eventually:

JPEG.APP1.APP1.APP1.APP1.APP1.APP1.APP1.APP1.APP1.APP1.APP1.APP1.APP1.APP1.APP1.APP1.APP1.APP1.APP1.APP1.APP1.APP1.APP1.APP1.APP1           = @20:294      
JPEG.APP1.APP1.APP1.APP1.APP1.APP1.APP1.APP1.APP1.APP1.APP1.APP1.APP1.APP1.APP1.APP1.APP1.APP1.APP1.APP1.APP1.APP1.APP1.APP1.APP1.Ifd0.DateTime                    = 'AAAAAAAAAAAAAAAAAAA'
JPEG.APP1.APP1.APP1.APP1.APP1.APP1.APP1.APP1.APP1.APP1.APP1.APP1.APP1.APP1.APP1.APP1.APP1.APP1.APP1.APP1.APP1.APP1.APP1.APP1.APP1.Ifd0.TAG_0x5100                  = 0

And so on. It looks like there's some sort of infinite loop here.

The image is attached here:

This issue was discovered using american fuzzy lop, with a starting image from AlexAltea's collection.