Em Mon, Oct 07, 2019 at 12:47:47PM +0200, Jiri Olsa escreveu:
> On Mon, Oct 07, 2019 at 10:02:21AM +0300, Adrian Hunter wrote:
> > slow_copyfile() opens the file by name, so "write" permissions must not
> > be removed in copyfile_mode_ns() before calling slow_copyfile().
> >
> > Example:
> >
> > Before:
> > $ sudo chmod +r /proc/kcore
> > $ sudo setcap "cap_sys_admin,cap_sys_ptrace,cap_syslog,cap_sys_rawio=ep"
> > tools/perf/perf
> > $ tools/perf/perf buildid-cache -k /proc/kcore
> > Couldn't add /proc/kcore
> >
> > After:
> > $ sudo chmod +r /proc/kcore
> > $ sudo setcap "cap_sys_admin,cap_sys_ptrace,cap_syslog,cap_sys_rawio=ep"
> > tools/perf/perf
> > $ tools/perf/perf buildid-cache -v -k /proc/kcore
> > kcore added to build-id cache directory
> > /home/ahunter/.debug/[kernel.kcore]/37e340b1b5a7cf4f57ba8de2bc777359588a957f/2019100709562289
> >
> > Signed-off-by: Adrian Hunter <[email protected]>
>
> Acked-by: Jiri Olsa <[email protected]>
Thanks, applied to perf/urgent.
- Arnaldo
> thanks,
> jirka
>
> > ---
> > tools/perf/util/copyfile.c | 8 +++++---
> > 1 file changed, 5 insertions(+), 3 deletions(-)
> >
> > diff --git a/tools/perf/util/copyfile.c b/tools/perf/util/copyfile.c
> > index 3fa0db136667..47e03de7c235 100644
> > --- a/tools/perf/util/copyfile.c
> > +++ b/tools/perf/util/copyfile.c
> > @@ -101,14 +101,16 @@ static int copyfile_mode_ns(const char *from, const
> > char *to, mode_t mode,
> > if (tofd < 0)
> > goto out;
> >
> > - if (fchmod(tofd, mode))
> > - goto out_close_to;
> > -
> > if (st.st_size == 0) { /* /proc? do it slowly... */
> > err = slow_copyfile(from, tmp, nsi);
> > + if (!err && fchmod(tofd, mode))
> > + err = -1;
> > goto out_close_to;
> > }
> >
> > + if (fchmod(tofd, mode))
> > + goto out_close_to;
> > +
> > nsinfo__mountns_enter(nsi, &nsc);
> > fromfd = open(from, O_RDONLY);
> > nsinfo__mountns_exit(&nsc);
> > --
> > 2.17.1
> >
--
- Arnaldo
