Created attachment 108147 [details] pdftoppm-eternalloop-stderr.pdf OS: Fedora 20 (running in virtualbox) Dependencies installed with: yum-builddep poppler Version: GIT Master Command line for loop demonstration: master/utils/pdftoppm <attached.pdf> /dev/null ############################################################################# GDB output: Starting program: /home/foobar/poppler/utils/.libs/lt-pdftoppm eternalloop-stderr-909-pdftoppmfuzz-3.pdf /dev/null Syntax Error: XObject 'x257' is wrong typeSyntax Error (59739): Bad 'Length' attribute in stream Syntax Error (59826): Unknown operator '<16>33' Syntax Error (59826): Too few (1) args to 'l' operator Syntax Error (60476): Bad 'Length' attribute in stream Syntax Error (60512): Unknown operator 'x<9c>+<e4>2P' Syntax Error: Unterminated string <<< Syntax Error: Unknown operator '<c1>' Syntax Error: Unknown operator 'w<05><fd>D<03><85><f4>b.<03>=<0b><85>r<a0><a8><17><10>gqE<c7>*<18><e8><19>' Syntax Error: Leftover args in content stream Syntax Error (60476): Bad 'Length' attribute in stream Syntax Error (60512): Unknown operator 'x<9c>+<e4>2P' Syntax Error: Unterminated string >>> <-- repeats infinitely
It would help if you tells us exactly what has been fuzzed in the pdf. If I have to spend more than 15 minutes trying to figure out the cause I will give up and find something more interesting to work on.
I have no idea, I just run it through a mutational fuzzer and wait for a crash. Besides, if you mutate hard enough it becomes almost impossible to figure out what the parser interprets the mutation as anyway, or if the problem is in the parser or later. I try to minimize the file size with the bug, but honestly I don't even have any way of analyzing a PDF's contents anyway. What do you use to get detailed information out of a PDF?
(In reply to MH from comment #2) > but honestly I don't even have any way of analyzing a PDF's contents > anyway. If you attach the original I can figure out what changed, > What do you use to get detailed information out of a PDF? A text editor and a copy of the PDF Reference.
Created attachment 108166 [details] Unfuzzed file Ah! Of course! Do you want unfuzzed files to the other reports as well? 3767c3767 < << /Length 318 0 R --- > << �/Length 318 0 R Guessing it's this one, unknown operator etc.
(In reply to MH from comment #4) > Do you want unfuzzed files to the other reports as well? Yes
Done. Also changed a lot of MIME types to application/pdf, didn't even notice that was a thing, whoops :)
Honestly i don't think it's eternal at all, it's just that there's a veeeeeeeeeeeeeeery big pattern fill (with 28954318 steps) and patterns are slow to draw, but if you give it enough time, i'm almost sure it'll finish.
File processed without issues in real 317m49.546s user 244m13.872s.
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