Obviously any reasonable input validation or length limit would disallow it.
The time requirement is only quadratic, not exponential, so it takes ridiculously long inputs to cause a problem. Andy > On Jun 11, 2020, at 12:26 PM, Robert Engels <reng...@ix.netcom.com> wrote: > > Why would you ever allow that regex? > >> On Jun 11, 2020, at 11:01 AM, Andy Balholm <andybalh...@gmail.com> wrote: >> >> It’s apparently quadratic in some cases. Yesterday fuzzing on >> github.com/andybalholm/cascadia <http://github.com/andybalholm/cascadia> >> found an input that triggered a timeout. The time was being spent compiling >> a 180-KB regex (which I’m attaching to this message). If I concatenate two >> copies of this file, the combined regex takes at least four times as long to >> compile. >> >> I plan to investigate further, and see if I can find a way to reproduce the >> issue that doesn’t look like it was generated by a fuzzer. >> >> Andy >> >> >> -- >> You received this message because you are subscribed to the Google Groups >> "golang-nuts" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to golang-nuts+unsubscr...@googlegroups.com >> <mailto:golang-nuts+unsubscr...@googlegroups.com>. >> To view this discussion on the web visit >> https://groups.google.com/d/msgid/golang-nuts/885CBC71-3268-4BEA-983E-A67B824AC654%40gmail.com >> >> <https://groups.google.com/d/msgid/golang-nuts/885CBC71-3268-4BEA-983E-A67B824AC654%40gmail.com?utm_medium=email&utm_source=footer>. >> <regex.txt> >> >> >>> On Jun 9, 2020, at 8:42 AM, 'Thomas Bushnell, BSG' via golang-nuts >>> <golang-nuts@googlegroups.com <mailto:golang-nuts@googlegroups.com>> wrote: >>> >>> On Tue, Jun 9, 2020 at 11:23 AM Axel Wagner <axel.wagner...@googlemail.com >>> <mailto:axel.wagner...@googlemail.com>> wrote: >>> If you actually read OPs second E-Mail, they did and they didn't find it >>> very clear. With that in mind, your message isn't very nice. >>> (Also, not to be repetitive or anything: ~80% of the messages in this >>> thread aren't actually concerned with what the complexity class *is*, but >>> whether it matters) >>> >>> The OP stopped participating in this exciting thread a long time ago. I >>> went and read through the code, and it seems pretty clear to me that it's >>> linear. >>> >>> -- >>> You received this message because you are subscribed to the Google Groups >>> "golang-nuts" group. >>> To unsubscribe from this group and stop receiving emails from it, send an >>> email to golang-nuts+unsubscr...@googlegroups.com >>> <mailto:golang-nuts+unsubscr...@googlegroups.com>. >>> To view this discussion on the web visit >>> https://groups.google.com/d/msgid/golang-nuts/CA%2BYjuxvQgnTKMM4FF4%3D4pspM-2nBJScNfCNinDv-2cNA09N%3DaQ%40mail.gmail.com >>> >>> <https://groups.google.com/d/msgid/golang-nuts/CA%2BYjuxvQgnTKMM4FF4%3D4pspM-2nBJScNfCNinDv-2cNA09N%3DaQ%40mail.gmail.com?utm_medium=email&utm_source=footer>. >> >> >> -- >> You received this message because you are subscribed to the Google Groups >> "golang-nuts" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to golang-nuts+unsubscr...@googlegroups.com >> <mailto:golang-nuts+unsubscr...@googlegroups.com>. >> To view this discussion on the web visit >> https://groups.google.com/d/msgid/golang-nuts/885CBC71-3268-4BEA-983E-A67B824AC654%40gmail.com >> >> <https://groups.google.com/d/msgid/golang-nuts/885CBC71-3268-4BEA-983E-A67B824AC654%40gmail.com?utm_medium=email&utm_source=footer>. -- You received this message because you are subscribed to the Google Groups "golang-nuts" group. To unsubscribe from this group and stop receiving emails from it, send an email to golang-nuts+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/golang-nuts/FB6E7B2F-E80E-4DAC-8A35-5029C205F565%40gmail.com.
