Bug #40011 for dhcp-public: dhcpd 4.3.2 crash

Hi, I'm having a bug report [1] that dhcpd 4.3.2 crashes upon first DHCPDISCOVER if specific configuration file [2] is used. There's also a packet dump [3], but I've been able to reproduce with any DHCPDISCOVER. I did a git-bisect and it led me to [4]. I don't see the problem with this commit reverted. With regards, -- Jiri [1] https://bugzilla.redhat.com/show_bug.cgi?id=1236324 [2] https://bugzilla.redhat.com/attachment.cgi?id=1045991 [3] https://bugzilla.redhat.com/attachment.cgi?id=1049534 [4] https://source.isc.org/cgi-bin/gitweb.cgi?p=dhcp.git;a=commitdiff;h=d9b2a590e835ec9d27f4c059ee07893b1acca110

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Thanks for relaying this to us and for your additional research. We are evaluating it currently.

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The configuration contains the line "option host-name = config-option server.ddns-hostname;". The default definition of "server.ddns-hostname" was changed in 4.3.2 to pick from one of three values; one of which is "config-option host-name". This rendered the configuration line above, infinitely recursive. We decided this was not a security issue, because there are many ways an operator could program their DCHP configurations to cause other infinite loops. We will be writing and publishing an Operational Note and updating our documentation about this soon. If you'd like to ask the original reporter why they used the offending string, we may be able to provide guidance on what they should do instead.

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