Bryan Drewery
2021-Oct-15 17:00 UTC
Disable tracing on FreeBSD using procctl. (OpenSSH Portable 8.8)
On 10/14/2021 5:44 PM, Darren Tucker wrote:> On Fri, 15 Oct 2021 at 10:48, mike tancsa <mike at sentex.net> wrote: >> With the commit below, OpenSSH portable 8.8 doesnt seem to work >> with sftp on FreeBSD with RELENG_12 and RELENG_13. sftp errors out with >> >> sftp-server[89445]: fatal: unable to make the process untraceable > > As a data point,our github CI tests on FreeBSD 12 & 13 VMs and our > test suite passes on them. I have confirmed that both set > HAVE_PROCCTL and that the code is being compiled in and just run a > manual test on 13 which worked. > > FreeBSD fbsd12 12.2-RELEASE-p3 FreeBSD 12.2-RELEASE-p3 GENERIC amd64 > > FreeBSD fbsd13 13.0-RELEASE FreeBSD 13.0-RELEASE #0 > releng/13.0-n244733-ea31abc261f: Fri Apr 9 04:24:09 UTC 2021 > root at releng1.nyi.freebsd.org:/usr/obj/usr/src/amd64.amd64/sys/GENERIC > amd64 >I think the tests may need to be improved as pid==0 represents a pseudo kernel process.> #include <sys/procctl.h> > #include <err.h> > #include <unistd.h> > > int > main(void) > { > int disable_trace = PROC_TRACE_CTL_DISABLE; > > if (procctl(P_PID, getpid(), PROC_TRACE_CTL, &disable_trace)) > err(1, "procctl"); > > return 0; > }With 0 it runs through truss fine. (Which I don't think it should but I'll take that up with FreeBSD)> procctl(P_PID,0,PROC_TRACE_CTL,0x7fffffffe478) = 0 (0x0)With getpid() truss gives an error since the process is already traced.> getpid() = 77976 (0x13098) > procctl(P_PID,77976,PROC_TRACE_CTL,0x7fffffffe478) ERR#16 'Device busy'-- Bryan Drewery -------------- next part -------------- A non-text attachment was scrubbed... Name: OpenPGP_signature Type: application/pgp-signature Size: 495 bytes Desc: OpenPGP digital signature URL: <http://lists.mindrot.org/pipermail/openssh-unix-dev/attachments/20211015/6ffe3fda/attachment-0001.asc>
Ed Maste
2021-Oct-19 17:40 UTC
Disable tracing on FreeBSD using procctl. (OpenSSH Portable 8.8)
On Fri, 15 Oct 2021 at 13:07, Bryan Drewery <bdrewery at freebsd.org> wrote:> > I think the tests may need to be improved as pid==0 represents a pseudo > kernel process.This is being fixed, but for compatibility with existing versions getpid() should indeed be used.
Ed Maste
2021-Nov-10 18:25 UTC
Disable tracing on FreeBSD using procctl. (OpenSSH Portable 8.8)
On Tue, 19 Oct 2021 at 13:40, Ed Maste <emaste at freebsd.org> wrote:> > On Fri, 15 Oct 2021 at 13:07, Bryan Drewery <bdrewery at freebsd.org> wrote: > > > > I think the tests may need to be improved as pid==0 represents a pseudo > > kernel process. > > This is being fixed, but for compatibility with existing versions > getpid() should indeed be used.This was fixed in FreeBSD by f833ab9dd187 but the procctl call should be changed in openssh.