Re: [PATCH] RDMA/ionic: bound node_desc sysfs read with %.64s

[Jason Gunthorpe]

On Tue, Apr 07, 2026 at 12:20:22PM +0300, Kai Zen wrote:
> node_desc[64] in struct ib_device is not guaranteed to be NUL-
> terminated. The core IB sysfs handler uses "%.64s" for exactly this
> reason (drivers/infiniband/core/sysfs.c:1307), since node_desc_store()
> performs a raw memcpy of up to IB_DEVICE_NODE_DESC_MAX bytes with no
> NUL termination:
> 
>   memcpy(desc.node_desc, buf, min_t(int, count, IB_DEVICE_NODE_DESC_MAX));
> 
> If exactly 64 bytes are written via the node_desc sysfs file, the
> array contains no NUL byte. The ionic hca_type_show() handler uses
> unbounded "%s" and will read past the end of node_desc into adjacent
> fields of struct ib_device until it encounters a NUL.
> 
> Match the core handler and bound the format specifier.
> 
> Verified against torvalds/linux.git master at bfe62a45.
> 
> Signed-off-by: Kai Aizen <kai.aizen.dev@xxxxxxxxx>
> ---
>  drivers/infiniband/hw/ionic/ionic_ibdev.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

Your diff is malformed but I fixed it up and added a Fixes tag.

Thanks,
Jason