From: James Morris <jmorris@namei.org>  on Friday, June 14, 2019 11:54 PM:
On Sat, 15 Jun 2019, Lubashev, Igor wrote:

quoted

Unfortunately, perf is using uid==0 and euid==0 as a "capability bits".


In tools/perf/util/evsel.c:
	static bool perf_event_can_profile_kernel(void)
	{
		return geteuid() == 0 || perf_event_paranoid() == -1;
	}

In tools/perf/util/symbol.c:
	static bool symbol__read_kptr_restrict(void)
	{
	...
		value = ((geteuid() != 0) || (getuid() != 0)) ?
				(atoi(line) != 0) :
				(atoi(line) == 2);
	...
	}

These are bugs. They should be checking for CAP_SYS_ADMIN.

Thanks for the suggestion.

Actually, the former one should be checking CAP_SYS_ADMIN, while the latter -- CAP_SYSLOG (see lib/vsprintf.c).

Just posted a patch to perf (http://lists.infradead.org/pipermail/linux-arm-kernel/2019-July/664552.html).

Thank you,

- Igor