From: dyslexicatheist <dyslexicatheist@protonmail.com>
To: "netfilter-devel@vger.kernel.org" <netfilter-devel@vger.kernel.org>
Subject: invalid read in
Date: Mon, 03 Feb 2020 13:54:31 +0000 [thread overview]
Message-ID: <gwRjoIGUgI5MEgxSob7CBSUwPbYkxILRc4_ZrYWYNI7d1-T5Ej95p3XkEY_f9hLqHK5nVun7dk6RqObi0c_4482IJ6s6U33PyS6Hrm4z46E=@protonmail.com> (raw)
Hello,
I've written a filter to parse out punicode from DNS payloads and rewrite the packet in case it contains any IDN (xn--) marker unless the IDN is on a whitelist. Valgrind reports that nfq_create_queue() returns uninitialized
bytes resulting in thiserror:
sudo valgrind --tool=memcheck --leak-check=yes --show-reachable=yes \
--num-callers=20 --track-fds=yes --track-origins=yes -s \
./nfq --syslog --facility LOG_LOCAL0 --log-level info \
--port 53 --renice -20 --rewrite-answer
==714384==
==714384== Syscall param socketcall.sendto(msg) points to uninitialised byte(s)
==714384== at 0x4B977C7: sendto (sendto.c:27)
==714384== by 0x486BE02: nfnl_send (in /usr/lib/x86_64-linux-gnu/libnfnetlink.so.0.2.0)
==714384== by 0x486DBD2: nfnl_query (in /usr/lib/x86_64-linux-gnu/libnfnetlink.so.0.2.0)
==714384== by 0x4A73995: nfq_set_mode (libnetfilter_queue.c:639)
==714384== by 0x10B247: start_nfqueue_processing (nfq.c:532)
==714384== by 0x10C289: main (nfq.c:987)
==714384== Address 0x1ffefefbfd is on thread 1's stack
==714384== in frame #3, created by nfq_set_mode (libnetfilter_queue.c:623)
==714384== Uninitialised value was created by a stack allocation
==714384== at 0x10A1B0: ??? (in /src/nfq/src/nfq)
After searching on this list archive, I found 1 question but without a follow-up answer:
https://marc.info/?l=netfilter-devel&m=137132916826745&w=4
Having already spent over a day chasing this. Not having come across other cases on github except this person self reporting[1] made me think it must be indeed something in my code that I'm missing and that could have triggered this. Or is it really rare (harmless) bug in libnetfilter?
[1] https://github.com/misje/dhcpoptinj/issues/5
thanks for any help,
~DA
next reply other threads:[~2020-02-03 13:54 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-03 13:54 dyslexicatheist [this message]
2020-02-03 16:31 ` invalid read in Phil Sutter
2020-02-03 17:14 ` dyslexicatheist
2020-02-03 17:30 ` Phil Sutter
2020-02-03 17:49 ` dyslexicatheist
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