There is a regular need in the kernel to provide a way to declare having
a dynamically sized set of trailing elements in a structure. Kernel code
should always use “flexible array members”[1] for these cases. The older
style of one-element or zero-length arrays should no longer be used[2].
Refactor the code a bit according to the use of a flexible-array member
in struct nfs4_file_layout_dsaddr instead of a one-element array, and
use the struct_size() helper.
This helps with the ongoing efforts to globally enable -Warray-bounds
and get us closer to being able to tighten the FORTIFY_SOURCE routines
on memcpy().
This issue was found with the help of Coccinelle and audited and fixed,
manually.
[1] https://en.wikipedia.org/wiki/Flexible_array_member
[2] https://www.kernel.org/doc/html/v5.10/process/deprecated.html#zero-length-and-one-element-arrays
Link: https://github.com/KSPP/linux/issues/79
Link: https://github.com/KSPP/linux/issues/109
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
u32 stripe_count;
u8 *stripe_indices;
u32 ds_num;
- struct nfs4_pnfs_ds *ds_list[1];
+ struct nfs4_pnfs_ds *ds_list[];
};
struct nfs4_filelayout_segment {
goto out_err_free_stripe_indices;
}
- dsaddr = kzalloc(sizeof(*dsaddr) +
- (sizeof(struct nfs4_pnfs_ds *) * (num - 1)),
- gfp_flags);
+ dsaddr = kzalloc(struct_size(dsaddr, ds_list, num), gfp_flags);
if (!dsaddr)
goto out_err_free_stripe_indices;