.TH OTS-VALIDATOR-CHECKER "1" "May 2021" "OpenType Sanitizer" "User Commands"
.SH NAME
ots-validator-checker \- font validation checker
.SH SYNOPSIS
.B ots-validator-checker
\fI\,FONT_FILE\/\fR
.SH DESCRIPTION
.PP
ots-validator-checker is a program which is intended to validate malformed fonts.
If the program detects that the font is invalid, it prints \(lqOK\(rq and
returns with 0 (success).
If it couldn’t detect any errors, the program then opens the transcoded font
and renders some characters using FreeType:
.PP
.RS
.nf
transcoded_font\ =\ ValidateAndTranscode(malicious_font);
if\ (validation_error)
\ \ Print("OK");
OpenAndRenderSomeCharacters(transcoded_font);\ \ #\ may\ cause\ SIGSEGV
Print("OK");
.fi
.RE
.PP
If SEGV doesn\(cqt raise inside FreeType library, the program prints \(lqOK\(rq
and returns with 0 as well.
You should run this tool under the
.BR catchsegv (1)
or
.BR valgrind (1)
command so that you can easily verify that all transformed fonts don\(cqt
crash the library (see the example below).
.SH EXAMPLES
.RS
.nf
$ for f in malformed/*.ttf ; do catchsegv ./ots-validator-checker "$f" ; done
OK: the malicious font was filtered: malformed/1.ttf
OK: the malicious font was filtered: malformed/2.ttf
OK: FreeType2 didn't crash: malformed/3.ttf
OK: the malicious font was filtered: malformed/4.ttf
.fi
.RE
.SH "REPORTING BUGS"
Report bugs to  <https://github.com/khaledhosny/ots/issues>
.SH "SEE ALSO"
.BR ots-idempotent (1),
.BR ots-perf (1),
.BR ots-sanitize (1),
.BR ots-side-by-side (1)