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Commit 2976b10f authored by Stephane Eranian's avatar Stephane Eranian Committed by Ingo Molnar
Browse files

perf: Disable monitoring on setuid processes for regular users 



There was a a bug in setup_new_exec(), whereby
the test to disabled perf monitoring was not
correct because the new credentials for the
process were not yet committed and therefore
the get_dumpable() test was never firing.

The patch fixes the problem by moving the
perf_event test until after the credentials
are committed.

Signed-off-by: default avatarStephane Eranian <eranian@google.com>
Tested-by: default avatarJiri Olsa <jolsa@redhat.com>
Acked-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: <stable@kernel.org>
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent c790b0ad

fs/exec.c

+9 −7
Original line number Diff line number Diff line
@@ -1135,13 +1135,6 @@ void setup_new_exec(struct linux_binprm * bprm) 
			set_dumpable(current->mm, suid_dumpable);

	}



	/*

	 * Flush performance counters when crossing a

	 * security domain:

	 */

	if (!get_dumpable(current->mm))

		perf_event_exit_task(current);



	/* An exec changes our domain. We are no longer part of the thread

	   group */
@@ -1205,6 +1198,15 @@ void install_exec_creds(struct linux_binprm *bprm) 


	commit_creds(bprm->cred);

	bprm->cred = NULL;



	/*

	 * Disable monitoring for regular users

	 * when executing setuid binaries. Must

	 * wait until new credentials are committed

	 * by commit_creds() above

	 */

	if (get_dumpable(current->mm) != SUID_DUMP_USER)

		perf_event_exit_task(current);

	/*

	 * cred_guard_mutex must be held at least to this point to prevent

	 * ptrace_attach() from altering our determination of the task's