io_uring: Fix incorrect sizeof operator for copy_from_user call

Static analysis is warning that the sizeof being used is should be
of *data->tags[i] and not data->tags[i]. Although these are the same
size on 64 bit systems it is not a portable assumption to assume
this is true for all cases.  Fix this by using a temporary pointer
tag_slot to make the code a clearer.

Addresses-Coverity: ("Sizeof not portable")
Fixes: d878c81610e1 ("io_uring: hide rsrc tag copy into generic helpers")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Reviewed-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/20210615130011.57387-1-colin.king@canonical.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/fs/io_uring.c b/fs/io_uring.c
index d665c9419ad3bc7762d3570a084d6eba23d8eaea..3692bbc7bd019792fdda3c75a546b0e6bba4adf2 100644 (file)
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -7230,8 +7230,10 @@ static int io_rsrc_data_alloc(struct io_ring_ctx *ctx, rsrc_put_fn *do_put,
        if (utags) {
                ret = -EFAULT;
                for (i = 0; i < nr; i++) {
-                       if (copy_from_user(io_get_tag_slot(data, i), &utags[i],
-                                          sizeof(data->tags[i])))
+                       u64 *tag_slot = io_get_tag_slot(data, i);
+
+                       if (copy_from_user(tag_slot, &utags[i],
+                                          sizeof(*tag_slot)))
                                goto fail;
                }
        }