K 10
svn:author
V 3
kib
K 8
svn:date
V 27
2017-03-12T13:48:24.636400Z
K 7
svn:log
V 665
Ktracing kevent(2) calls with unusual arguments might leads to an
overly large allocation requests.

When ktrace-ing io, sys_kevent() allocates memory to copy the
requested changes and reported events.  Allocations are sized by the
incoming syscall lengths arguments, which are user-controlled, and
might cause overflow in calculations or too large allocations.

Since io trace chunks are limited by ktr_geniosize, there is no sense
it even trying to satisfy unbounded allocations.  Export ktr_geniosize
and clamp the buffers sizes in advance.

PR:	217435
Reported by:	Tim Newsham <tim.newsham@nccgroup.trust>
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week

END