RE: Patch "perf ftrace: Use CAP_SYS_ADMIN instead of euid==0" has been added to the 5.3-stable tree

[Lubashev, Igor]

> On Thu, Oct 3, 2019 at 3:50 AM Greg KH <greg@xxxxxxxxx> wrote:
> Sent: Thursday, October 3, 2019 3:50 AM
> 
> On Tue, Oct 01, 2019 at 01:15:54PM -0400, Sasha Levin wrote:
> > This is a note to let you know that I've just added the patch titled
> >
> >     perf ftrace: Use CAP_SYS_ADMIN instead of euid==0
> >
> > to the 5.3-stable tree which can be found at:
> >
> > http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;
> > a=summary
> >
> > The filename of the patch is:
> >      perf-ftrace-use-cap_sys_admin-instead-of-euid-0.patch
> > and it can be found in the queue-5.3 subdirectory.
> >
> > If you, or anyone else, feels it should not be added to the stable
> > tree, please let <stable@xxxxxxxxxxxxxxx> know about it.
> >
> >
> >
> > commit 54a277c389061fc501624f51a13426d7b797f5f7
> > Author: Igor Lubashev <ilubashe@xxxxxxxxxx>
> > Date:   Wed Aug 7 10:44:17 2019 -0400
> >
> >     perf ftrace: Use CAP_SYS_ADMIN instead of euid==0
> >
> >     [ Upstream commit c766f3df635de14295e410c6dd5410bc416c24a0 ]
> 
> 
> Sasha, this patch is breaking the build of perf in the stable branches.
> Can you fix it up, or drop it?

This patch is fixing what's been broken forever in perf, so it is improving perf tool.  But it is not fixing a vuln in the kernel itself.

In any case, this patch is a part of a series.  You would need the following to make that patch compile:
97993bd6eb89 perf tools: Add NO_LIBCAP=1 to the minimal build test
c22e150e3afa perf tools: Add helpers to use capabilities if present

Also, if you believe this update to perf tool warrants inclusion in a stable update, I'd rather point you at the entire series:

d06e5fad8c46 perf tools: Warn that perf_event_paranoid can restrict kernel symbols
8859aedefefe perf symbols: Use CAP_SYSLOG with kptr_restrict checks
aa97293ff129 perf evsel: Kernel profiling is disallowed only when perf_event_paranoid > 1
dda1bf8ea78a perf tools: Use CAP_SYS_ADMIN with perf_event_paranoid checks
e9a6882f267a perf event: Check ref_reloc_sym before using it
73e5de70dca0 perf ftrace: Improve error message about capability to use ftrace
c766f3df635d perf ftrace: Use CAP_SYS_ADMIN instead of euid==0
083c1359b0e0 perf tools: Add CAP_SYSLOG define for older systems
97993bd6eb89 perf tools: Add NO_LIBCAP=1 to the minimal build test
c22e150e3afa perf tools: Add helpers to use capabilities if present
74d5f3d06f70 tools build: Add capability-related feature detection

Best,

- Igor