Date: Mon, 16 Mar 2015 11:15:45 -0400 From: John Baldwin <jhb@freebsd.org> To: Ian Lepore <ian@freebsd.org> Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org Subject: Re: svn commit: r279997 - head/sys/netinet Message-ID: <3051755.qWx5SR0ixE@ralph.baldwin.cx> In-Reply-To: <1426377491.39727.4.camel@freebsd.org> References: <201503141811.t2EIBPeE006504@svn.freebsd.org> <12123739.Rz3jP8R4fM@ralph.baldwin.cx> <1426377491.39727.4.camel@freebsd.org>
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On Saturday, March 14, 2015 05:58:11 PM Ian Lepore wrote: > On Sat, 2015-03-14 at 17:52 -0400, John Baldwin wrote: > > On Saturday, March 14, 2015 06:11:25 PM Ian Lepore wrote: > > > Author: ian > > > Date: Sat Mar 14 18:11:24 2015 > > > New Revision: 279997 > > > URL: https://svnweb.freebsd.org/changeset/base/279997 > > > > > > Log: > > > Use sbuf_new_for_sysctl() instead of plain sbuf_new() to ensure sysctl > > > string returned to userland is nulterminated. > > > > > > PR: 195668 > > > > This is not safe. sbuf_printf() is invoked with a lock held, so it isn't > > safe for the sbuf code to do a drain here. With sbuf_new_for_sysctl(), > > any call to an sbuf routine is a potential page fault, so the handler must > > either use sysctl_wire_old_buffer(), or the contents need to be output in > > one go. For this case I would prefer to use sbuf_len(sb) + 1 (or add > > INCLUDENUL to the args when creating it) and leave the sole SYSCTL_OUT() > > at the end. > > > > You will want to check the one or two other places you converted for this > > same issue as well. > > > > Doh! I was trying to keep an eye out for locks, but I missed that one. > Fixed in r280014. > > I'm at that point in a big maintenance task where I've looked at too > much code in too short a time, thanks for keeping a watchful eye on all > this. No problem. I've replied to a few others that I think need a similar fix. However, fixing the larger bug is much appreciated. :) -- John Baldwin
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