Fix getsockopt(..., IPPROTO_IP, IP_OPTIONS, ..., ...)

[tuexen]

Summary

r336616 copies inp->inp_options using the m_dup() function. However, this function expects an mbuf packet header at the beginning, which is not true in this case. Therefore, use m_copym() instead of m_dup().

Test Plan

Use the attached test program to verify that getsockopt(..., IPPROTO_IP, IP_OPTIONS, ..., ...) works. Without the patch, the system panics when running the test program.

This issue what found by running syzkaller.

ip_options.c526 BDownload