From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mathieu Desnoyers Subject: [PATCH for 5.4 1/3] rseq: Fix: Reject unknown flags on rseq unregister Date: Tue, 17 Sep 2019 14:29:57 -0400 Message-ID: <20190917182959.16333-2-mathieu.desnoyers@efficios.com> References: <20190917182959.16333-1-mathieu.desnoyers@efficios.com> Return-path: In-Reply-To: <20190917182959.16333-1-mathieu.desnoyers@efficios.com> Sender: linux-kernel-owner@vger.kernel.org To: Thomas Gleixner Cc: linux-kernel@vger.kernel.org, Peter Zijlstra , "Paul E . McKenney" , Boqun Feng , "H . Peter Anvin" , Paul Turner , linux-api@vger.kernel.org, stable@vger.kernel.org, Mathieu Desnoyers List-Id: linux-api@vger.kernel.org It is preferrable to reject unknown flags within rseq unregistration rather than to ignore them. It is an oversight caused by the fact that the check for unknown flags is after the rseq unregister flag check. Signed-off-by: Mathieu Desnoyers Cc: Thomas Gleixner Cc: Peter Zijlstra (Intel) Cc: "Paul E. McKenney" Cc: Boqun Feng Cc: "H . Peter Anvin" Cc: Paul Turner Cc: linux-api@vger.kernel.org Cc: # v4.18+ --- kernel/rseq.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/kernel/rseq.c b/kernel/rseq.c index 27c48eb7de40..a4f86a9d6937 100644 --- a/kernel/rseq.c +++ b/kernel/rseq.c @@ -310,6 +310,8 @@ SYSCALL_DEFINE4(rseq, struct rseq __user *, rseq, u32, rseq_len, int ret; if (flags & RSEQ_FLAG_UNREGISTER) { + if (flags & ~RSEQ_FLAG_UNREGISTER) + return -EINVAL; /* Unregister rseq for current thread. */ if (current->rseq != rseq || !current->rseq) return -EINVAL; -- 2.17.1