linux-kernel - [PATCH 2/2] io_uring: fix openat/statx's filename leak

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Message-Id: <14f45901fa84b4f9f46e7cf9afa20ac1324f6ebd.1581157341.git.asml.silence@gmail.com>
Date:   Sat,  8 Feb 2020 13:28:03 +0300
From:   Pavel Begunkov <asml.silence@...il.com>
To:     Jens Axboe <axboe@...nel.dk>, io-uring@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH 2/2] io_uring: fix openat/statx's filename leak

As in the previous patch, make openat*_prep() and statx_prep() to
handle double prepartion to avoid resource leakage.

Signed-off-by: Pavel Begunkov <asml.silence@...il.com>
---
 fs/io_uring.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index f5aa2fdccf7a..c3bac9d850a5 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -2536,6 +2536,8 @@ static int io_openat_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 		return -EINVAL;
 	if (sqe->flags & IOSQE_FIXED_FILE)
 		return -EINVAL;
+	if (req->flags & REQ_F_NEED_CLEANUP)
+		return 0;
 
 	req->open.dfd = READ_ONCE(sqe->fd);
 	req->open.how.mode = READ_ONCE(sqe->len);
@@ -2564,6 +2566,8 @@ static int io_openat2_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 		return -EINVAL;
 	if (sqe->flags & IOSQE_FIXED_FILE)
 		return -EINVAL;
+	if (req->flags & REQ_F_NEED_CLEANUP)
+		return 0;
 
 	req->open.dfd = READ_ONCE(sqe->fd);
 	fname = u64_to_user_ptr(READ_ONCE(sqe->addr));
@@ -2763,6 +2767,8 @@ static int io_statx_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 		return -EINVAL;
 	if (sqe->flags & IOSQE_FIXED_FILE)
 		return -EINVAL;
+	if (req->flags & REQ_F_NEED_CLEANUP)
+		return 0;
 
 	req->open.dfd = READ_ONCE(sqe->fd);
 	req->open.mask = READ_ONCE(sqe->len);
-- 
2.24.0