commoncap: don't alloc the credential unless needed in cap_task_prctl
In function cap_task_prctl(), we would allocate a credential unconditionally and then check if we support the requested function. If not we would release this credential with abort_creds() by using RCU method. But on some archs such as powerpc, the sys_prctl is heavily used to get/set the floating point exception mode. So the unnecessary allocating/releasing of credential not only introduce runtime overhead but also do cause OOM due to the RCU implementation. This patch removes abort_creds() from cap_task_prctl() by calling prepare_creds() only when we need to modify it. Reported-by:Kevin Hao <haokexin@gmail.com> Signed-off-by:
Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Reviewed-by:
Paul Moore <paul@paul-moore.com> Acked-by:
Serge E. Hallyn <serge.hallyn@ubuntu.com> Reviewed-by:
Kees Cook <keescook@chromium.org> Signed-off-by:
James Morris <james.l.morris@oracle.com>
parent
fd33c436
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