io_uring: fix off-by-one in sync cancelation file check

The passed in index should be validated against the number of registered
files we have, it needs to be smaller than the index value to avoid going
one beyond the end.

Fixes: 78a861b949 ("io_uring: add sync cancelation API through io_uring_register()")
Reported-by: Luo Likang <luolikang@nsfocus.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Jens Axboe 2022-08-23 07:26:08 -06:00
parent e1d0c6d05a
commit 47abea041f

View File

@ -218,7 +218,7 @@ static int __io_sync_cancel(struct io_uring_task *tctx,
(cd->flags & IORING_ASYNC_CANCEL_FD_FIXED)) { (cd->flags & IORING_ASYNC_CANCEL_FD_FIXED)) {
unsigned long file_ptr; unsigned long file_ptr;
if (unlikely(fd > ctx->nr_user_files)) if (unlikely(fd >= ctx->nr_user_files))
return -EBADF; return -EBADF;
fd = array_index_nospec(fd, ctx->nr_user_files); fd = array_index_nospec(fd, ctx->nr_user_files);
file_ptr = io_fixed_file_slot(&ctx->file_table, fd)->file_ptr; file_ptr = io_fixed_file_slot(&ctx->file_table, fd)->file_ptr;