io_uring: set table->files[i] to NULL when io_sqe_file_register failed

While io_sqe_file_register() failed in __io_sqe_files_update(),
table->files[i] still point to the original file which may freed
soon, and that will trigger use-after-free problems.

Cc: stable@vger.kernel.org
Fixes: f3bd9dae3708 ("io_uring: fix memleak in __io_sqe_files_update()")
Signed-off-by: Jiufei Xue <jiufei.xue@linux.alibaba.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/fs/io_uring.c b/fs/io_uring.c
index a06b562..b1ccd70 100644 (file)
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -7353,6 +7353,7 @@ static int __io_sqe_files_update(struct io_ring_ctx *ctx,
                        table->files[index] = file;
                        err = io_sqe_file_register(ctx, file, i);
                        if (err) {
+                               table->files[index] = NULL;
                                fput(file);
                                break;
                        }