1OTS-VALIDATOR-CHECKER(1)         User Commands        OTS-VALIDATOR-CHECKER(1)
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NAME

6       ots-validator-checker - font validation checker
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SYNOPSIS

9       ots-validator-checker FONT_FILE
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DESCRIPTION

12       ots-validator-checker  is  a program which is intended to validate mal‐
13       formed fonts.  If the program detects that  the  font  is  invalid,  it
14       prints  “OK”  and  returns with 0 (success).  If it couldn’t detect any
15       errors, the program then opens the transcoded  font  and  renders  some
16       characters using FreeType:
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18              transcoded_font = ValidateAndTranscode(malicious_font);
19              if (validation_error)
20                Print("OK");
21              OpenAndRenderSomeCharacters(transcoded_font);  # may cause SIGSEGV
22              Print("OK");
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24       If  SEGV doesn’t raise inside FreeType library, the program prints “OK”
25       and returns with 0 as well.  You should run this tool under the  catch‐
26       segv(1)  or  valgrind(1) command so that you can easily verify that all
27       transformed fonts don’t crash the library (see the example below).
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EXAMPLES

30              $ for f in malformed/*.ttf ; do catchsegv ./ots-validator-checker "$f" ; done
31              OK: the malicious font was filtered: malformed/1.ttf
32              OK: the malicious font was filtered: malformed/2.ttf
33              OK: FreeType2 didn't crash: malformed/3.ttf
34              OK: the malicious font was filtered: malformed/4.ttf
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REPORTING BUGS

37       Report bugs to  <https://github.com/khaledhosny/ots/issues>
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SEE ALSO

40       ots-idempotent(1), ots-perf(1), ots-sanitize(1), ots-side-by-side(1)
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44OpenType Sanitizer                 May 2021           OTS-VALIDATOR-CHECKER(1)
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