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From:   Dylan Yudaken <dylany@fb.com>
To:     <io-uring@vger.kernel.org>
CC:     <axboe@kernel.dk>, <asml.silence@gmail.com>,
        <linux-kernel@vger.kernel.org>, <kernel-team@fb.com>,
        Dylan Yudaken <dylany@fb.com>
Subject: [PATCH 3/4] io_uring: verify resv is 0 in ringfd register/unregister
Date:   Tue, 12 Apr 2022 09:30:41 -0700
Message-ID: <20220412163042.2788062-4-dylany@fb.com>
In-Reply-To: <20220412163042.2788062-1-dylany@fb.com>
References: <20220412163042.2788062-1-dylany@fb.com>
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Only allow resv field to be 0 in struct io_uring_rsrc_update user
arguments.

Fixes: e7a6c00dc77a ("io_uring: add support for registering ring file des=
criptors")
Signed-off-by: Dylan Yudaken <dylany@fb.com>
---
 fs/io_uring.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index e899192ffb77..a84bfec97d0d 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -10533,6 +10533,11 @@ static int io_ringfd_register(struct io_ring_ctx=
 *ctx, void __user *__arg,
 			break;
 		}
=20
+		if (reg.resv) {
+			ret =3D -EINVAL;
+			break;
+		}
+
 		if (reg.offset =3D=3D -1U) {
 			start =3D 0;
 			end =3D IO_RINGFD_REG_MAX;
@@ -10579,7 +10584,7 @@ static int io_ringfd_unregister(struct io_ring_ct=
x *ctx, void __user *__arg,
 			ret =3D -EFAULT;
 			break;
 		}
-		if (reg.offset >=3D IO_RINGFD_REG_MAX) {
+		if (reg.resv || reg.offset >=3D IO_RINGFD_REG_MAX) {
 			ret =3D -EINVAL;
 			break;
 		}
--=20
2.30.2