Segfault in examples/dns on a malformed DNS packet

UpstandingHackers / hammer

Parser combinators for binary formats, in C. Yes, in C. What? Don't look at me like that.

GNU General Public License v2.0

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Segfault in examples/dns on a malformed DNS packet #198

Open pictyeye opened 3 years ago

pictyeye commented 3 years ago

The attached packet (found using AFL) triggers a segmentation fault in act_domain (dns.c): segfaulter.txt (NB: I had to base64 encode the packet to submit the issue on GH)

To reproduce the bug, you must first run the dns server using

scons examples
build/opt/examples/dns

Then, you can trigger the segfault using

openssl enc -d -base64 < segfaulter.txt | nc localhost 53