From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Date: Wed, 11 Dec 2019 16:17:11 +0000 (-0500)
Subject: rseq: Reject unknown flags on rseq unregister
X-Git-Tag: v5.5-rc7~14^2~1
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=66528a4575eee9f5a5270219894ab6178f146e84;p=thirdparty%2Flinux.git

rseq: Reject unknown flags on rseq unregister

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 <mathieu.desnoyers@efficios.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20191211161713.4490-2-mathieu.desnoyers@efficios.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---

diff --git a/kernel/rseq.c b/kernel/rseq.c
index 27c48eb7de402..a4f86a9d6937c 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;