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perf: Disable monitoring on setuid processes for regular users

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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: Stephane Eranian <eranian@google.com>
Tested-by: Jiri Olsa <jolsa@redhat.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: <stable@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Stephane Eranian 2013-06-20 11:36:28 +02:00 committed by Ingo Molnar
parent c790b0ad23
commit 2976b10f05
1 changed files with 9 additions and 7 deletions
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16
fs/exec.c
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@ -1135,13 +1135,6 @@ void setup_new_exec(struct linux_binprm * bprm)
set_dumpable(current->mm, suid_dumpable); 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 /* An exec changes our domain. We are no longer part of the thread
group */ group */
@ -1205,6 +1198,15 @@ void install_exec_creds(struct linux_binprm *bprm)
commit_creds(bprm->cred); commit_creds(bprm->cred);
bprm->cred = NULL; 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 * cred_guard_mutex must be held at least to this point to prevent
* ptrace_attach() from altering our determination of the task's * ptrace_attach() from altering our determination of the task's